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WO2013161242A1 - Method for correcting mechanism error of articulated robot - Google Patents

Method for correcting mechanism error of articulated robot Download PDF

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Publication number
WO2013161242A1
WO2013161242A1 PCT/JP2013/002665 JP2013002665W WO2013161242A1 WO 2013161242 A1 WO2013161242 A1 WO 2013161242A1 JP 2013002665 W JP2013002665 W JP 2013002665W WO 2013161242 A1 WO2013161242 A1 WO 2013161242A1
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WO
WIPO (PCT)
Prior art keywords
articulated robot
jig
hand
error
spherical
Prior art date
Application number
PCT/JP2013/002665
Other languages
French (fr)
Japanese (ja)
Inventor
高野　健
末藤　伸幸
藤原　茂喜
法上　司
Original Assignee
パナソニック株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by パナソニック株式会社 filed Critical パナソニック株式会社
Priority to CN201380021242.2A priority Critical patent/CN104245243B/en
Priority to JP2014512338A priority patent/JP5914831B2/en
Publication of WO2013161242A1 publication Critical patent/WO2013161242A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J9/00—Programme-controlled manipulators
    • B25J9/16—Programme controls
    • B25J9/1615—Programme controls characterised by special kind of manipulator, e.g. planar, scara, gantry, cantilever, space, closed chain, passive/active joints and tendon driven manipulators
    • B25J9/1623—Parallel manipulator, Stewart platform, links are attached to a common base and to a common platform, plate which is moved parallel to the base
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00—Program-control systems
    • G05B2219/30—Nc systems
    • G05B2219/39—Robotics, robotics to robotics hand
    • G05B2219/39044—Estimate error model from error at different attitudes and points

Definitions

  • the present invention relates to a technology for correcting a mechanical error of an articulated robot.
  • the present invention has been made in view of such problems, and it is an object of the present invention to provide correction of a mechanical error of an articulated robot that does not deteriorate the correction accuracy of the mechanical error.
  • a method of correcting mechanical errors of an articulated robot is a method of correcting mechanical errors of an articulated robot that corrects mechanical errors of an articulated robot having six degrees of freedom. Acquiring an angle of a joint of the multi-joint robot while restraining the hand of the multi-joint robot at each of at least four different positions on the surface of the flat jig or the spherical jig; And correcting the mechanical error of the articulated robot using the angles of the joints of the articulated robot acquired in the acquiring step.
  • the deterioration of the correction accuracy of the mechanical error can be prevented.
  • FIG. 1 is a view showing the attitude of the articulated robot according to the first embodiment of the present invention
  • FIG. 1 (a) is a view showing the attitude of the flat jig at a first position.
  • (B) is a view showing the attitude of the plane jig at the second position
  • (c) of FIG. 1 is a view showing the attitude of the plane jig at the third position
  • (d) of FIG. It is a figure which shows the attitude
  • FIG. 2 is a block diagram showing a control unit of the articulated robot according to Embodiment 1 of the present invention.
  • FIG. 1 is a view showing the attitude of the articulated robot according to Embodiment 1 of the present invention.
  • FIG. 3 is a flowchart showing a method of correcting a mechanical error of the articulated robot according to the first embodiment of the present invention.
  • FIG. 4 is a flowchart showing a specific example of a method of correcting a mechanical error of the articulated robot according to the first embodiment of the present invention.
  • FIG. 5 is a view showing the attitude of the articulated robot according to the second embodiment of the present invention, and FIG. 5 (a) is a view showing the attitude of the spherical jig at the first position. (B) is a view showing the attitude of the spherical jig at the second position, (c) of FIG. 5 is a view showing the attitude of the spherical jig at the third position, (d) of FIG.
  • FIG. 6 is a view showing a posture of an articulated robot according to a third embodiment of the present invention
  • FIG. 6 (a) is a view showing a posture at a first position of a plane jig;
  • B) is a figure which shows the attitude
  • (c) of FIG. 6 is a figure which shows the attitude
  • FIG. 7 is a view showing the posture of a conventional articulated robot.
  • the conventional articulated robot 100 includes a fixing unit 102, a plurality of joints 101, arms 104 and 105, and a hand 103.
  • the fixed part 102 of the articulated robot 100 and the hand 103 are connected by the arms 104 and 105 which connect a plurality of joints 101 with each other.
  • the hand 103 of the articulated robot 100 moves as the angle of each joint 101 changes.
  • the tip end 111 of the member 110 attached to the end 103 of the articulated robot 100 is engaged by being fitted into the hole 113 of the plate 112, and this is based on the angle of the joint 101 of the articulated robot 100 in the restrained state.
  • the mechanical error of the articulated robot 100 is estimated and corrected.
  • the method of correcting mechanical errors of an articulated robot includes correcting mechanical errors of an articulated robot that corrects mechanical errors of an articulated robot having six degrees of freedom. Obtaining an angle of a joint of the articulated robot in a state in which the hand of the articulated robot is restrained at each of at least four different positions on the surface of a planar jig or a spherical jig; And correcting the mechanical error of the articulated robot using the angles of the joints of the articulated robot acquired in the acquiring step.
  • the shape of the surface of the jig is used to correct the mechanical error, the shape of the surface of the jig is maintained even if the temperature of the jig fluctuates. Therefore, it is possible to prevent the deterioration of the correction accuracy of the mechanism error.
  • FIG. 1 is a view showing a posture of an articulated robot according to Embodiment 1 of the present invention.
  • 1A is a view showing the attitude of the plane jig 7 at the first position 51
  • FIG. 1B is a view showing the attitude of the plane jig 7 at the second position 52
  • FIG. 1C is a view showing the attitude of the plane jig 7 at the third position 53
  • FIG. 1D is a view showing the attitude of the plane jig 7 at the fourth position 54.
  • the first position 51, the second position 52, the third position 53, and the fourth position 54 are positions different from each other on the surface of the plane jig 7.
  • the articulated robot 31 in Embodiment 1 of this invention is a parallel link robot, as shown in FIG.
  • the basic configuration of the articulated robot 31 of the first embodiment will be described with reference to FIG.
  • the articulated robot 31 includes a base 21, a hand 2, six pairs of links 3 and arms 4 connecting the base 21 and the hand 2. , 6 motors 5 as an example of a drive source, and a control unit 40 that controls these.
  • the base 21 and the arm 4 are connected by joints 1 a.
  • the link 3 and the arm 4 are each connected by a joint 1 b.
  • the link 3 and the hand 2 are respectively connected by a joint 1c.
  • the joint 1a is configured by a turning pair, and the joints 1b and 1c are configured by a spherical pair.
  • the base 21 and the hand 2 are connected by six power transmission units.
  • the power transmission unit is a member that is mainly composed of the link 3 and the arm 4 and transmits power between the base 21 and the hand 2.
  • the base 21 and the hand 2 are plate members of a regular hexagon.
  • the arm 4 is rotatable around the rotation axis of the motor 5 fixed to the base 21.
  • Each motor 5 is provided with an encoder 6 as an example of joint angle detection means.
  • the articulated robot 31 can detect the angle of the arm 4 by using the encoder 6.
  • the flat contact portion 8 is fixed to the hand 2.
  • the flat contact portion 8 is a member for stabilizing the posture of the hand 2 when pressed against the surface of the flat jig 7.
  • the flat contact portion 8 is a member for making the posture of the hand 2 always be the same with the surface of the flat jig 7 when pressed against the surface of the flat jig 7.
  • the flat contact portion 8 of the first embodiment is a rectangular solid whose bottom surface is square.
  • the shape of the flat contact portion 8 is not limited as long as the top surface and the bottom surface are parallel to each other and the hand 2 makes surface contact in parallel to the flat surface of the flat jig 7.
  • the flat contact portion 8 is an example of the contact portion.
  • the plane jig 7 is an example of a jig, and the surface thereof is formed of a plane.
  • the six power transmission units are divided into three groups, with two arranged in parallel as one group. That is, in the first embodiment, the base 21 and the hand 2 are connected by three sets of power transmission units. Further, in each of the base 21 and the hand 2, three sets of power transmission units are connected at equal intervals of an angle of 120 °.
  • the articulated robot 31 of the first embodiment functions as a parallel link robot.
  • the hand 2 of the articulated robot 31 according to the first embodiment can perform an operation with six degrees of freedom.
  • the first embodiment makes it possible to perform such correction of the mechanical error of the articulated robot 31 using the plane jig 7. Specifically, the flat contact portion 8 fixed to the hand 2 of the articulated robot 31 is pressed to contact at four different positions 51 to 54 on the surface of the flat jig 7, and the four different positions 51 to 54 are obtained. Control is performed so that the angle of the tip 2 with respect to the normal direction in the above becomes the same, and the mechanism error of the articulated robot 31 is measured and corrected based on the joint angle in each posture. That is, in the first embodiment, when measuring a mechanical error, the posture of the hand 2 is always the same posture with respect to the surface of the plane jig 7 at four different positions 51 to 54 of the plane jig 7.
  • the flat jig 7 according to the first embodiment is a member whose surface is flat, and is fixed so that the positional relationship between the articulated robot 31 and the base 21 does not change. Detailed contents of the method of correcting the mechanical error in the first embodiment will be described later.
  • FIG. 2 is a block diagram showing the control unit 40 that performs each process of the method of correcting mechanical errors of the articulated robot according to the first embodiment.
  • the control unit 40 includes an acquisition unit 41 and a correction unit 42.
  • the acquiring unit 41 acquires the value of the encoder 6 in a state in which the hand 2 is restrained by the planar jig 7 at each of the four positions 51 to 54 on the surface of the planar jig 7.
  • the correction unit 42 calculates and corrects a mechanism error of the articulated robot 31 using the value of the encoder 6 acquired by the acquisition unit 41.
  • FIG. 3 is a flowchart showing a method of correcting a mechanical error of the articulated robot 31 according to the first embodiment.
  • the acquiring unit 41 acquires the angle of the joint 1 a of the articulated robot 31 in a state in which the hand 2 of the articulated robot 31 is restrained at each of four different positions 51 to 54 on the surface of the plane jig 7. (Step S01: acquisition step).
  • the correction unit 42 calculates and corrects a mechanical error of the articulated robot 31 using the angle of the joint 1a of the articulated robot 31 acquired in the acquisition step of step S01 (step S02: correction step) .
  • FIG. 4 is a flowchart showing a specific example of a method of correcting a mechanical error of the articulated robot 31 according to the first embodiment.
  • the posture of the hand 2 is restrained such that the angle of the hand 2 is pressed to the surface of the jig 7 so that the angle of the hand 2 becomes the same as the normal direction of the plane jig 7.
  • the acquisition unit 41 acquires and stores the value ⁇ i of the encoder 6 (step S12).
  • the acquisition unit 41 determines whether the index i is 4 or more, that is, ii4 (step S13).
  • step S12 to step S14 the acquiring unit 41 determines that the angle of the tip 2 of the four arbitrary positions 51 to 54 on the surface of the plane jig 7 is the method of the surface of the plane jig 7
  • values ⁇ 1 to ⁇ 4 of the encoder 6 in that state are acquired and stored.
  • Steps S11 to S15 are an example of the acquisition process of step S01.
  • step S15 is an example of the correction process of step S02.
  • Step S15 is calculation to calculate the mechanism error of the first embodiment from the obtained value ⁇ i of the encoder 6.
  • An example of the mechanism error according to the first embodiment is an error of the length L of the link 3.
  • the kinematics equation representing the relationship between the angle of the arm 4 and the position and posture of the hand 2 is (Equation 1), and is expressed by variables P i , ⁇ i and L. It is derived as the represented function F1.
  • ⁇ i ( ⁇ 1 i, ⁇ 2 i, ⁇ 3 i, ⁇ 4 i, ⁇ 5 i, ⁇ 6 i) is a six-dimensional vector are the respective values of the encoder 6 of the motor 5 of the articulated robot 31. That is, ⁇ i is a value obtained by restraining the hand 2 at four different positions 51 to 54 of the plane jig 7.
  • L (L1, L2, L3, L4, L5, L6) indicates the length of six links 3 to be corrected, and is a six-dimensional vector.
  • the length L of the link 3 is an unknown value.
  • the error of the length L of the link 3 is calculated and corrected by calculating the value of the length L of the link 3 by calculation from now on.
  • the mechanical dimensions of the articulated robot 31 other than the length L of the link 3 are the same as the design values.
  • the actual length L of the link 3 determined by the following description is an example of the measurement value.
  • the posture of the tip 2 of the articulated robot 31 at four different positions 51 to 54 is constrained in the same direction (the normal direction of the plane jig 7) at each of the positions 51 to 54. Therefore, as shown in the following (Equation 2), a function N represented by variables P i , ⁇ , ⁇ is derived. That is, in the first embodiment, the relationship indicating that the posture of the hand 2 is in the constrained state is derived as the function N of (Expression 2).
  • Equation (3) X h , Y h and Z h represent the position of the hand 2 in the coordinate system, and X b , Y b and Z b represent the position after conversion to the fixed coordinate system.
  • the predetermined condition is that the unit vector in the Z direction in the coordinate system of the hand 2 of the articulated robot 31 is constrained in the normal direction of the surface of the plane jig 7 and the rotation of the hand coordinate system around the Z axis is , Not constrained.
  • Equation (5) ⁇ and ⁇ are unknown values, and values will be obtained by calculation in the future.
  • Equation (6) is a one-dimensional equation, and X i , Y i and Z i are components in three directions of the X-axis direction, the Y-axis direction, and the Z-axis direction, which indicate the position of P i .
  • a, b, c, d are unknown values representing a plane in a three-dimensional space, and are obtained by calculation in the future.
  • Example 5 is a relational expression showing the posture in the normal direction at four different positions 51 to 54 of the plane jig 7, and (Expression 6) is a plane of the surface of the plane jig 7. It is a relational expression showing four different positions 51-54.
  • the 36 unknown parameters can be determined by calculating the above 36 simultaneous equations by numerical analysis using, for example, the Newton method.
  • a measurement value of the length L of the link 3 is obtained.
  • an error of the length L of the link 3 can be calculated.
  • by correcting the error of the length L of the link 3 it is possible to correct the mechanical error of the articulated robot 31.
  • the temperature is higher than that of the conventional correction of the mechanical error using the holes of the plate. It is hard for the change of the state to change to occur. This is because, when the planar jig 7 having a planar shape expands or contracts due to a temperature change, the distance between the holes used for the correction of the conventional mechanism error changes, but the mechanism error of the first embodiment is corrected. It is because the shape of the used surface does not change easily. Therefore, by using the method of correcting mechanical errors of the articulated robot according to the first embodiment, it is possible to correct mechanical errors of the articulated robot which is less likely to decrease in accuracy with respect to temperature change.
  • the four positions on the surface of the plane jig 7 pressing the plane contact portion 8 of the hand 2 may be any different positions, it is necessary that the positions of the articulated robot 31 change at each position. There is.
  • the articulated robot 31 of the first embodiment is a parallel link robot, it is preferable that the four positions on the surface of the plane jig 7 be positions different in distance from the center of the robot. Further, the four different positions 51 to 54 may be positions at which the distances between the respective positions are approximately equal. By these, the correction
  • the posture of the articulated robot 31 changes indicates that the angles of one or more joints 1a, 1b, and 1c change.
  • the four different positions 51 to 54 are positions where the mutual distance is as long as possible within the movable range of the articulated robot 31, and the shape connecting the four is It may be a square shape.
  • the shape of the surface of the plane jig 7 is described as a plane parallel to the base 21. However, even if the plane is inclined with respect to the base 21, the above-mentioned (formula 1) The correction method of the mechanism error using equation (5) and equation (6) can be applied.
  • the solution is obtained by measuring with the hand 2 restrained at four different positions 51 to 54 on the surface of the plane jig 7
  • the solution can not be uniquely determined.
  • FIG. 5 is a view showing the posture of an articulated robot 32 according to Embodiment 2 of the present invention.
  • FIG. 5A is a view showing the attitude of the spherical jig 9 at the first position 61
  • FIG. 5B is a view showing the attitude of the spherical jig 9 at the second position 62.
  • FIG. 5C shows the attitude of the spherical jig 9 at the third position 63
  • FIG. 5D shows the attitude of the spherical jig 9 at the fourth position 64.
  • the first position 61, the second position 62, the third position 63 and the fourth position 64 are positions different from each other on the surface of the spherical jig 9.
  • the components of the articulated robot 32 according to the second embodiment are the same as the articulated robot 31 of FIG. 1 except that the flat contact portion 8 of FIG. Since there is a description, the description will be omitted appropriately.
  • the correction of the mechanical error of the articulated robot 32 according to the second embodiment is performed using a spherical jig 9 whose surface is a spherical surface.
  • the spherical jig 9 is fixed so that the positional relationship between the articulated robot 32 and the base 21 does not change.
  • the spherical contact portion 10 fixed to the hand 2 has a concave surface (concave curved surface) of the same radius as the spherical jig 9.
  • the concave surface of the spherical contact portion 10 is a surface that can contact the spherical jig 9 without a gap.
  • the spherical contact portion 10 may have at least a shape that uniquely determines an attitude and a position when contacting the spherical jig 9.
  • the spherical contact portion 10 may be, for example, a hollow cylindrical shape, but in order to ensure contact with the spherical jig 9, the spherical contact portion 10 having a concave curved surface as shown in FIG. 5 is desirable.
  • the spherical contact portion 10 is an example of the contact portion.
  • the spherical jig 9 is an example of a jig, and the surface thereof is formed of a spherical surface.
  • the spherical contact portion 10 of the hand 2 is brought into contact with four different positions 61 to 64 of the surface of the spherical jig 9 to obtain four different positions 61.
  • the posture of the hand 2 is restrained by the spherical jig 9 so that the angles of the hand 2 with respect to the normal direction in the range of to 64 are the same.
  • the spherical contact portion 10 of the hand 2 is spherical jig 9 at four different positions 61 to 64.
  • the center position of the spherical surface of the spherical contact portion 10 in the hand 2 coordinate system of the hand 2 coincides with the center of the spherical surface of the spherical jig 9 at each of four different positions 61 to 64 Restrain as. That is, the hand 2 is fixed by the spherical contact portion 10 so that an axis (for example, Z axis) extending in a predetermined direction in the hand coordinate system always coincides with the center of the spherical surface of the spherical jig 9.
  • an axis for example, Z axis
  • the processing of the method of correcting mechanical errors of the articulated robot 32 according to the second embodiment is the same as the processing of the method of correcting mechanical errors of the articulated robot according to the first embodiment except for the calculation formula. The description of the process is omitted.
  • T (T x , T y , T z ) is a three-dimensional vector representing the position of the center of the spherical surface of the spherical contact portion 10 of the hand 2.
  • T is an unknown value, which can be calculated by a future calculation.
  • B (Bx, By, Bz) is a three-dimensional vector representing the central coordinates of the spherical jig 9 in the fixed coordinate system of the articulated robot 32.
  • B is an unknown value, which can be obtained by calculation in the future.
  • the 36 unknown parameters can be determined by calculating the above 36 simultaneous equations by numerical analysis using, for example, the Newton method. Thereby, the measurement value of the length L of the link 3 can be obtained.
  • the tip 2 of the articulated robot 32 is pressed against the four different positions 61 to 64 on the surface of the spherical jig 9 so that the tip 2 is moved.
  • the mechanical error of the articulated robot 32 (the design value and the value obtained for the length L of the link 3 ) Can be calculated and corrected.
  • a spherical jig 9 having a spherical shape that is not easily deformed even when the temperature changes is used. Therefore, it is possible to correct the mechanical error of the articulated robot which is less likely to reduce the accuracy with respect to the temperature change.
  • the four positions on the surface of the spherical jig 9 pressing the hand 2 may be any different positions, but the positions of the articulated robot 32 need to be different from one another at each position. .
  • the four different positions 61 to 64 are approximately equally spaced apart from one another, and the angles of the posture of the hand 2 at the four different positions 61 to 64 differ as much as possible, It is desirable to improve the correction accuracy of the mechanism error.
  • the solution is obtained by measuring with the hand 2 restrained at four different positions 61 to 64 on the surface of the spherical jig 9
  • the solution can not be uniquely determined.
  • the configuration obtained by using the least square method or the average or the like of the value obtained by measuring in a state in which the hand 2 is restrained to the surface of the spherical jig 9 at five or more positions of the spherical jig 9 Accuracy can be improved.
  • the method of correcting mechanical errors of the articulated robot according to the second embodiment includes the correction of the articulated robot 32 incorporated in an apparatus in which it is difficult to install the large plane flat jig 7 as in the first embodiment. It is effective when doing.
  • FIG. 6 is a view showing the attitude of the articulated robot 33 according to Embodiment 3 of the present invention
  • FIG. 6 (a) is a view showing the attitude of the plane jig 7 at the first position 71.
  • 6 (b) shows the attitude of the plane jig 7 at the second position 72
  • FIG. 6 (c) shows the attitude of the plane jig 7 at the third position 73.
  • FIG. 6D is a view showing the attitude of the plane jig 7 at the fourth position 74.
  • the first position 71, the second position 72, the third position 73, and the fourth position 74 are positions different from each other on the surface of the plane jig 7.
  • the articulated robot 33 according to the third embodiment is different from the articulated robot 31 according to the first embodiment and the parallel link robot of the articulated robot 32 according to the second embodiment, and is a serial link. It is a robot.
  • the articulated robot 33 has a hand 12, a robot fixing unit 18, and six links 13 connecting the hand 12 and the robot fixing unit 18.
  • the hand 12 and the robot fixing portion 18 are connected in series by six links 13.
  • the hand 12 is fixed to one of the links 13, and the six links 13 and the robot fixing portion 18 are connected by six joints 11 respectively.
  • the hand 12 can perform an operation with six degrees of freedom by the six motors 14 provided to the six joints 11, respectively.
  • the motor 14 is provided with an encoder 15 as joint angle detection means, and the angle of each joint 11 can be detected using this encoder 15.
  • the hand contact 12 has a flat contact portion 16 for stabilizing the posture of the hand 12 so as to always be the same posture with respect to the surface of the plane jig 7 when pressed against the surface of the plane jig 7. It is fixed.
  • the flat contact portion 16 is an example of the contact portion.
  • the flat contact portion 16 is a rectangular solid whose bottom is a square, but if the top and bottom surfaces are parallel and the tip 12 is in plane contact with the flat surface of the flat jig 7 in parallel,
  • the shape is not limited.
  • the flat jig 7 is fixed so that the positional relationship between the articulated robot 33 and the robot fixing unit 18 does not change.
  • the posture and position of the tip 12 are planarized at four different positions 71 to 74 on the surface of the planar jig 7.
  • the mechanical error of the articulated robot 33 can be corrected using the value of the encoder 15 acquired by restraining the tool 7.
  • the process of the method of correcting the mechanical error of the articulated robot 33 according to the third embodiment is the same as the process of the method of correcting the mechanical error of the articulated robot 31 according to the first embodiment except for the calculation formula. The description of the process flow is omitted.
  • the kinematics equation representing the relationship between the angle of the motor 14 and the position and posture of the hand 12 in the articulated robot 33 according to the third embodiment shown in FIG. 6 is P i , ⁇ i as shown in (Expression 9) , And is derived as a function F2 represented by variables.
  • Equation (9) is a six-dimensional equation.
  • P i (X i , Y i , Z i , ⁇ xi , ⁇ yi , ⁇ zi ) is a six-dimensional vector representing the position and posture of the hand 12 and i (i is an integer of 1 to 4) is at four points Is an index that indicates the hand of P i is an unknown value, which can be calculated by a future calculation.
  • ⁇ i ( ⁇ 1 i, ⁇ 2 i, ⁇ 3 i, ⁇ 4 i, ⁇ 5 i, ⁇ 6 i) is a six-dimensional vector which is the value of the encoder 15 of each motor 14 of the articulated robot 33. That is, ⁇ i is a value acquired by restraining the hand 2 at four different positions 71 to 74 of the plane jig 7 and is known.
  • K (K1, K2, K3, K4, K5, K6) is the length of the six links 13 to be corrected (dimension 17 in FIG. 6) and is a six-dimensional vector. K is an unknown value, which can be calculated by a future calculation. In the third embodiment, it is assumed that the mechanical dimensions of the articulated robot 33 other than the length K of the link 13 are as ideal as design values.
  • the length K of the link 13 can be determined as in the first embodiment.
  • the tip 12 of the articulated robot 33 is pressed against four different positions 71 to 74 on the surface of the plane jig 7.
  • the multi-joint robot 33 difference between the design value and the measurement value for the length K of the link 13 using the value of the encoder 15 in the state restrained by the surface of the plane jig 7 calculate.
  • the flat jig 7 having a planar shape that is not easily deformed even when the temperature changes is used. Therefore, the possibility that the accuracy decreases with respect to the temperature change is reduced, and the mechanical error of the articulated robot 33 can be corrected with high accuracy.
  • the four positions 71 to 74 on the surface of the plane jig 7 pressing the end 12 are any different positions, they need to be four positions at which the posture of the articulated robot 33 changes at each position. . It is desirable that the four different positions 71 to 74 be approximately equally spaced apart from each other in order to improve the correction accuracy of the mechanism error.
  • the shape of the surface of the flat jig 7 is described as a plane parallel to the surface on which the robot fixing portion 18 is attached, but the surface on which the robot fixing portion 18 is attached is On the other hand, even if it is an inclined plane, the method of correcting a mechanical error using the above (Equation 5), (Equation 6) and (Equation 9) is applicable.
  • the solution is measured by constraining the hand 12 at four different positions 71 to 74 on the surface of the plane jig 7. Although it can be determined, if the position restrained by the plane jig 7 is less than four, the solution can not be uniquely determined.
  • the configuration accuracy can be further improved by using the method of least squares or averaging the value obtained by measuring with the hand 12 restrained to the surface of the plane jig 7 at five or more positions at four or more positions. Can be enhanced.
  • the hands 2 and 12 of the articulated robots 31 to 33 are at four different positions on the surface of the plane jig 7 or the spherical jig 9.
  • the values of the encoders 6 and 15 were obtained while being constrained by 51 to 54, 61 to 64, and 71 to 74.
  • the encoder 6 is moved while moving the tips 2 and 12 in a state in which the tips 2 and 12 of the articulated robots 31 to 33 are pressed against the surface of the plane jig 7 or the spherical jig 9 and the posture is restrained.
  • a plurality of the fifteen values may be obtained continuously and automatically at predetermined timings (for example, at intervals of 0.1 s).
  • the acquisition step of acquiring and storing the values of the encoders 6 and 15 which are angles of the joints of the articulated robots 31 to 33 is continuously and automatically performed a plurality of times while moving the hands 2 and 12.
  • the correction of the mechanical error of the articulated robots 31 to 33 can be easily performed in a short time.
  • angles of the articulated robots 31 to 33 stored in the acquisition step are planar jigs in which the hands 2 and 12 are restrained. 7.
  • the hand 2 and 12 for the pressure sensor or the like is used as a method for the multi-joint robots 31 to 33 to determine the state in which the hands 2 and 12 are restrained by the flat jig 7 and the spherical jig 9. It is conceivable to use a sensor capable of detecting the magnitude of such a force. According to the above configuration, the step of pressing the tips 2 and 12 against the flat jig 7 and the spherical jig 9 can be performed automatically.
  • the method of correcting mechanical errors of an articulated robot according to the present invention is useful as a method of correcting mechanical errors of an industrial articulated robot.

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  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Orthopedic Medicine & Surgery (AREA)
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Abstract

The present invention relates to a method for correcting a mechanism error of an articulated robot (31) by using a value obtained by restricting the position and posture of a finger (2) of the articulated robot (31) which has six degrees of freedom by a plane jig (7). The present invention comprises: a step of acquiring the angle of a joint of the articulated robot (31) in a state of restriction in which the finger (2) is restricted by the plane jig (7) at each of at least four different positions (51 to 54) on a surface of the plane jig (7) so that the relationship between the posture of the finger (2) and a normal line on surfaces of the positions (51 to 54) is identical; and a step of correcting the mechanical error of the articulated robot (31) by using the angle obtained in the acquisition step.

Description

多関節ロボットの機構誤差の補正方法Correction method of mechanical error of articulated robot
　本発明は、多関節ロボットの機構誤差を補正する技術に関する。 The present invention relates to a technology for correcting a mechanical error of an articulated robot.
　多関節ロボットの機構誤差の補正方法として、穴と穴の距離が予め測定された複数の穴を有するプレートを治具として用いた方法がある（例えば、特許文献１参照）。 As a correction method of a mechanical error of the articulated robot, there is a method using a plate having a plurality of holes in which the distance between the holes is measured in advance as a jig (see, for example, Patent Document 1).
　このような従来の多関節ロボットの機構誤差の補正方法では、多関節ロボットの手先をプレートの穴に嵌合させることで拘束し、拘束された状態の多関節ロボットの関節の角度に基づいてこの多関節ロボットの機構誤差を推定して補正する。 In such a conventional method of correcting mechanical errors of the articulated robot, the hand of the articulated robot is restrained by fitting it in the hole of the plate, and the angle of the joint of the articulated robot in the restrained state is used. Estimate and correct mechanical errors of articulated robots.
特許第３３８８０１６号公報Patent No. 3388016
　しかしながら、従来の機構誤差の補正方法では、プレートの状態や穴の精度によっては、機構誤差の補正精度が悪化する可能性があるという課題がある。 However, in the conventional method of correcting the mechanical error, there is a problem that the correction accuracy of the mechanical error may be deteriorated depending on the state of the plate and the accuracy of the hole.
　本発明は、このような課題に鑑みてなされたものであり、機構誤差の補正精度が悪化しない多関節ロボットの機構誤差の補正を提供することを目的とする。 The present invention has been made in view of such problems, and it is an object of the present invention to provide correction of a mechanical error of an articulated robot that does not deteriorate the correction accuracy of the mechanical error.
　上記目的を達成するために、本発明の一態様に係る多関節ロボットの機構誤差の補正方法は、６自由度を有する多関節ロボットの機構誤差を補正する多関節ロボットの機構誤差の補正方法であって、平面治具又は球面治具の表面の少なくとも４箇所の異なる位置それぞれにおいて、前記多関節ロボットの手先を拘束した状態で、前記多関節ロボットの関節の角度を取得する取得工程と、前記取得工程において取得された前記多関節ロボットの関節の角度を用いて、前記多関節ロボットの機構誤差を算出して補正する補正工程と、を有することを特徴とする。 In order to achieve the above object, a method of correcting mechanical errors of an articulated robot according to an aspect of the present invention is a method of correcting mechanical errors of an articulated robot that corrects mechanical errors of an articulated robot having six degrees of freedom. Acquiring an angle of a joint of the multi-joint robot while restraining the hand of the multi-joint robot at each of at least four different positions on the surface of the flat jig or the spherical jig; And correcting the mechanical error of the articulated robot using the angles of the joints of the articulated robot acquired in the acquiring step.
　本発明の多関節ロボットの機構誤差の補正によれば、機構誤差の補正精度の悪化を防ぐことができる。 According to the correction of the mechanical error of the articulated robot of the present invention, the deterioration of the correction accuracy of the mechanical error can be prevented.
図１は本発明の実施の形態１に係る多関節ロボットの姿勢を示す図であって、図１の（ａ）は平面治具の第一の位置における姿勢を示す図であり、図１の（ｂ）は平面治具の第二の位置における姿勢を示す図であり、図１の（ｃ）は平面治具の第三の位置における姿勢を示す図であり、図１の（ｄ）は平面治具の第四の位置における姿勢を示す図である。FIG. 1 is a view showing the attitude of the articulated robot according to the first embodiment of the present invention, and FIG. 1 (a) is a view showing the attitude of the flat jig at a first position. (B) is a view showing the attitude of the plane jig at the second position, (c) of FIG. 1 is a view showing the attitude of the plane jig at the third position, (d) of FIG. It is a figure which shows the attitude | position in the 4th position of a plane jig. 図２は本発明の実施の形態１に係る多関節ロボットの制御部を示すブロック図である。FIG. 2 is a block diagram showing a control unit of the articulated robot according to Embodiment 1 of the present invention. 図３は本発明の実施の形態１に係る多関節ロボットの機構誤差の補正方法を示すフローチャートである。FIG. 3 is a flowchart showing a method of correcting a mechanical error of the articulated robot according to the first embodiment of the present invention. 図４は本発明の実施の形態１に係る多関節ロボットの機構誤差の補正方法の具体的な一例を示すフローチャートである。FIG. 4 is a flowchart showing a specific example of a method of correcting a mechanical error of the articulated robot according to the first embodiment of the present invention. 図５は本発明の実施の形態２に係る多関節ロボットの姿勢を示す図であって、図５の（ａ）は球面治具の第一の位置における姿勢を示す図であり、図５の（ｂ）は球面治具の第二の位置における姿勢を示す図であり、図５の（ｃ）は球面治具の第三の位置における姿勢を示す図であり、図５の（ｄ）は球面治具の第四の位置における姿勢を示す図である。FIG. 5 is a view showing the attitude of the articulated robot according to the second embodiment of the present invention, and FIG. 5 (a) is a view showing the attitude of the spherical jig at the first position. (B) is a view showing the attitude of the spherical jig at the second position, (c) of FIG. 5 is a view showing the attitude of the spherical jig at the third position, (d) of FIG. It is a figure which shows the attitude | position in the 4th position of a spherical surface jig | tool. 図６は本発明の実施の形態３に係る多関節ロボットの姿勢を示す図であって、図６の（ａ）は平面治具の第一の位置における姿勢を示す図であり、図６の（ｂ）は平面治具の第二の位置における姿勢を示す図であり、図６の（ｃ）は平面治具の第三の位置における姿勢を示す図であり、図６の（ｄ）は平面治具の第四の位置における姿勢を示す図である。FIG. 6 is a view showing a posture of an articulated robot according to a third embodiment of the present invention, and FIG. 6 (a) is a view showing a posture at a first position of a plane jig; (B) is a figure which shows the attitude | position in the 2nd position of a plane jig | tool, (c) of FIG. 6 is a figure which shows the attitude | position in the 3rd position of a plane jig, (d) of FIG. It is a figure which shows the attitude | position in the 4th position of a plane jig. 図７は従来の多関節ロボットの姿勢を示す図である。FIG. 7 is a view showing the posture of a conventional articulated robot.
　（本発明の基礎となった知見）
　本発明者は、「背景技術」の欄において記載した、多関節ロボットの機構誤差の補正方法に関し、以下の問題が生じることを見出した。 (Findings that formed the basis of the present invention)
The present inventor has found that the following problems occur with respect to the method of correcting mechanical errors of the articulated robot described in the "Background Art" section.
　図７に示すように、従来の多関節ロボット１００は、固定部１０２、複数の関節１０１、アーム１０４、１０５、手先１０３を備える。多関節ロボット１００の固定部１０２と手先１０３とは、複数の関節１０１同士をつなぐアーム１０４、１０５により接続されている。この多関節ロボット１００の手先１０３は、各関節１０１の角度が変わることで移動する。 As shown in FIG. 7, the conventional articulated robot 100 includes a fixing unit 102, a plurality of joints 101, arms 104 and 105, and a hand 103. The fixed part 102 of the articulated robot 100 and the hand 103 are connected by the arms 104 and 105 which connect a plurality of joints 101 with each other. The hand 103 of the articulated robot 100 moves as the angle of each joint 101 changes.
　そして、多関節ロボット１００の手先１０３に取り付けた部材１１０の先端１１１をプレート１１２の穴１１３に嵌合させることで拘束し、拘束された状態の多関節ロボット１００の関節１０１の角度に基づいてこの多関節ロボット１００の機構誤差を推定して補正する。 Then, the tip end 111 of the member 110 attached to the end 103 of the articulated robot 100 is engaged by being fitted into the hole 113 of the plate 112, and this is based on the angle of the joint 101 of the articulated robot 100 in the restrained state. The mechanical error of the articulated robot 100 is estimated and corrected.
　しかしながら、従来の機構誤差の補正方法では、相互間の距離が正確に計測された複数の穴１１３を有するプレート１１２を用いる必要がある。このため、例えば、室温変動などによりプレート１１２の温度が変動し、プレート１１２が膨張又は収縮して複数の穴１１３間の距離が変動した場合、機構誤差の補正精度が悪化するという問題がある。 However, in the conventional method of correcting mechanical errors, it is necessary to use a plate 112 having a plurality of holes 113 in which the distance between them is accurately measured. Therefore, for example, when the temperature of the plate 112 fluctuates due to room temperature fluctuation and the plate 112 expands or contracts and the distance between the plurality of holes 113 fluctuates, there is a problem that the correction accuracy of the mechanism error is deteriorated.
　このような問題を解決するために、本発明の一態様に係る多関節ロボットの機構誤差の補正方法は、６自由度を有する多関節ロボットの機構誤差を補正する多関節ロボットの機構誤差の補正方法であって、平面治具又は球面治具の表面の少なくとも４箇所の異なる位置それぞれにおいて前記多関節ロボットの手先を拘束した状態で、前記多関節ロボットの関節の角度を取得する取得工程と、前記取得工程において取得された前記多関節ロボットの関節の角度を用いて、前記多関節ロボットの機構誤差を算出して補正する補正工程と、を有することを特徴とする。 In order to solve such a problem, the method of correcting mechanical errors of an articulated robot according to an aspect of the present invention includes correcting mechanical errors of an articulated robot that corrects mechanical errors of an articulated robot having six degrees of freedom. Obtaining an angle of a joint of the articulated robot in a state in which the hand of the articulated robot is restrained at each of at least four different positions on the surface of a planar jig or a spherical jig; And correcting the mechanical error of the articulated robot using the angles of the joints of the articulated robot acquired in the acquiring step.
　これによれば、機構誤差の補正にジグの表面の形状を利用しているため、ジグの温度が変動しても、ジグの表面の形状は維持される。このため、機構誤差の補正精度の悪化を防ぐことができる。 According to this, since the shape of the surface of the jig is used to correct the mechanical error, the shape of the surface of the jig is maintained even if the temperature of the jig fluctuates. Therefore, it is possible to prevent the deterioration of the correction accuracy of the mechanism error.
　以下、本発明の一態様に係る実施の形態について、図面を参照しながら説明する。なお、以下で説明する実施の形態は、いずれも本発明の一具体例を示すものである。以下の実施の形態で示される数値、形状、構成要素、構成要素の配置位置及び接続形態、ステップ、ステップの順序などは、本発明の一例である。また、以下の実施の形態における構成要素のうち、最上位概念を示す独立請求項に記載されていない構成要素については、任意の構成要素として説明される。また、以下の説明において、同じ構成には同じ符号を付して、適宜説明を省略している。 Hereinafter, an embodiment according to one aspect of the present invention will be described with reference to the drawings. Each embodiment described below shows one specific example of the present invention. Numerical values, shapes, components, arrangement positions and connection forms of components, steps, order of steps, and the like shown in the following embodiments are an example of the present invention. Further, among the components in the following embodiments, components not described in the independent claim indicating the highest concept are described as arbitrary components. Moreover, in the following description, the same code | symbol is attached | subjected to the same structure and description is abbreviate | omitted suitably.
　（実施の形態１）
　図１は本発明の実施の形態１に係る多関節ロボットの姿勢を示す図である。図１の（ａ）は平面治具７の第一の位置５１における姿勢を示す図であり、図１の（ｂ）は平面治具７の第二の位置５２における姿勢を示す図であり、図１の（ｃ）は平面治具７の第三の位置５３における姿勢を示す図であり、図１の（ｄ）は平面治具７の第四の位置５４における姿勢を示す図である。なお、第一の位置５１、第二の位置５２、第三の位置５３及び第四の位置５４は、平面治具７の表面において、互いに異なる位置である。 Embodiment 1
FIG. 1 is a view showing a posture of an articulated robot according to Embodiment 1 of the present invention. 1A is a view showing the attitude of the plane jig 7 at the first position 51, and FIG. 1B is a view showing the attitude of the plane jig 7 at the second position 52, FIG. 1C is a view showing the attitude of the plane jig 7 at the third position 53, and FIG. 1D is a view showing the attitude of the plane jig 7 at the fourth position 54. The first position 51, the second position 52, the third position 53, and the fourth position 54 are positions different from each other on the surface of the plane jig 7.
　本発明の実施の形態１における多関節ロボット３１は、図１に示すように、パラレルリンクロボットである。図１を用いて、本実施の形態１の多関節ロボット３１の基本構成を説明する。 The articulated robot 31 in Embodiment 1 of this invention is a parallel link robot, as shown in FIG. The basic configuration of the articulated robot 31 of the first embodiment will be described with reference to FIG.
　図１の（ａ）に示すように、本実施の形態１の多関節ロボット３１は、基台２１と、手先２と、基台２１及び手先２を接続する６組のリンク３及びアーム４と、駆動源の一例としての６つのモータ５と、これらを制御する制御部４０と、を備える。 As shown in (a) of FIG. 1, the articulated robot 31 according to the first embodiment includes a base 21, a hand 2, six pairs of links 3 and arms 4 connecting the base 21 and the hand 2. , 6 motors 5 as an example of a drive source, and a control unit 40 that controls these.
　基台２１とアーム４とは、それぞれ関節１ａにより接続されている。リンク３とアーム４とは、それぞれ関節１ｂにより接続されている。リンク３と手先２とは、それぞれ関節１ｃにより接続されている。関節１ａは回り対偶で構成され、関節１ｂ、１ｃは球面対偶で構成されている。 The base 21 and the arm 4 are connected by joints 1 a. The link 3 and the arm 4 are each connected by a joint 1 b. The link 3 and the hand 2 are respectively connected by a joint 1c. The joint 1a is configured by a turning pair, and the joints 1b and 1c are configured by a spherical pair.
　本実施の形態１では、基台２１と手先２とは、６つの動力伝達部によって接続されている。ここで、動力伝達部とは、主にリンク３及びアーム４で構成されて、基台２１と手先２との間で動力を伝達するための部材である。また、本実施の形態１では、図１に示すように、基台２１及び手先２は、正六角形の板状部材である。アーム４は、基台２１に固定されたモータ５の回転軸を中心として回転可能である。各モータ５は、関節角度検出手段の一例としてのエンコーダ６をそれぞれ備えている。多関節ロボット３１は、エンコーダ６を用いることで、アーム４の角度を検出することができる。手先２には、平面接触部８が固定されている。平面接触部８は、平面治具７の表面に押し付けられたときに、手先２の姿勢を安定させるための部材である。具体的には、平面接触部８は、平面治具７の表面に押し付けられたときに、手先２の姿勢を平面治具７の表面に対して常に同じにするための部材である。本実施の形態１の平面接触部８は、底面が正方形の直方体である。なお、平面接触部８は、天面と底面とが平行であり、手先２が平面治具７の平面である表面に対して平行に面接触するものであれば、その形状は限定されない。平面接触部８は、接触部の一例である。また、平面治具７は、治具の一例であり、その表面が平面で構成されている。 In the first embodiment, the base 21 and the hand 2 are connected by six power transmission units. Here, the power transmission unit is a member that is mainly composed of the link 3 and the arm 4 and transmits power between the base 21 and the hand 2. In the first embodiment, as shown in FIG. 1, the base 21 and the hand 2 are plate members of a regular hexagon. The arm 4 is rotatable around the rotation axis of the motor 5 fixed to the base 21. Each motor 5 is provided with an encoder 6 as an example of joint angle detection means. The articulated robot 31 can detect the angle of the arm 4 by using the encoder 6. The flat contact portion 8 is fixed to the hand 2. The flat contact portion 8 is a member for stabilizing the posture of the hand 2 when pressed against the surface of the flat jig 7. Specifically, the flat contact portion 8 is a member for making the posture of the hand 2 always be the same with the surface of the flat jig 7 when pressed against the surface of the flat jig 7. The flat contact portion 8 of the first embodiment is a rectangular solid whose bottom surface is square. The shape of the flat contact portion 8 is not limited as long as the top surface and the bottom surface are parallel to each other and the hand 2 makes surface contact in parallel to the flat surface of the flat jig 7. The flat contact portion 8 is an example of the contact portion. The plane jig 7 is an example of a jig, and the surface thereof is formed of a plane.
　本実施の形態１では、６つの動力伝達部は、平行に配置された２つを１組として、３組に分けられる。すなわち、本実施の形態１では、３組の動力伝達部により、基台２１と手先２とが接続されている。また、基台２１及び手先２それぞれにおいて、３組の動力伝達部は、１２０°の角度で均等な間隔で接続されている。 In the first embodiment, the six power transmission units are divided into three groups, with two arranged in parallel as one group. That is, in the first embodiment, the base 21 and the hand 2 are connected by three sets of power transmission units. Further, in each of the base 21 and the hand 2, three sets of power transmission units are connected at equal intervals of an angle of 120 °.
　以上の構成により、本実施の形態１の多関節ロボット３１は、パラレルリンクロボットとして機能する。また、本実施の形態１の多関節ロボット３１の手先２は、６自由度の動作を行うことができる。 With the above configuration, the articulated robot 31 of the first embodiment functions as a parallel link robot. In addition, the hand 2 of the articulated robot 31 according to the first embodiment can perform an operation with six degrees of freedom.
　本実施の形態１は、このような多関節ロボット３１の機構誤差の補正を、平面治具７を用いて行うことを可能とする。具体的には、平面治具７の表面において異なる位置５１～５４の４箇所に多関節ロボット３１の手先２に固定された平面接触部８を押し付けて接触させ、４箇所の異なる位置５１～５４における法線方向に対する手先２の角度が同一となる姿勢に制御し、それぞれの姿勢での関節角度に基づいて多関節ロボット３１の機構誤差を測定して補正する。すなわち、本実施の形態１では、機構誤差を測定する際に、平面治具７の４箇所の異なる位置５１～５４において、手先２の姿勢を平面治具７の表面に対して常に同じ姿勢にすると共に、手先２の位置及び姿勢を拘束している。なお、本実施の形態１に係る平面治具７は、その表面が平面な部材であり、多関節ロボット３１の基台２１との位置関係が変化しないように固定されている。本実施の形態１における機構誤差の補正方法の詳しい内容については、後述する。 The first embodiment makes it possible to perform such correction of the mechanical error of the articulated robot 31 using the plane jig 7. Specifically, the flat contact portion 8 fixed to the hand 2 of the articulated robot 31 is pressed to contact at four different positions 51 to 54 on the surface of the flat jig 7, and the four different positions 51 to 54 are obtained. Control is performed so that the angle of the tip 2 with respect to the normal direction in the above becomes the same, and the mechanism error of the articulated robot 31 is measured and corrected based on the joint angle in each posture. That is, in the first embodiment, when measuring a mechanical error, the posture of the hand 2 is always the same posture with respect to the surface of the plane jig 7 at four different positions 51 to 54 of the plane jig 7. And constrain the position and posture of the hand 2. The flat jig 7 according to the first embodiment is a member whose surface is flat, and is fixed so that the positional relationship between the articulated robot 31 and the base 21 does not change. Detailed contents of the method of correcting the mechanical error in the first embodiment will be described later.
　図２は、本実施の形態１の多関節ロボットの機構誤差の補正方法の各処理を行う制御部４０を示すブロック図である。 FIG. 2 is a block diagram showing the control unit 40 that performs each process of the method of correcting mechanical errors of the articulated robot according to the first embodiment.
　図２に示すように、制御部４０は、取得部４１と、補正部４２とを有する。取得部４１は、平面治具７の表面の４箇所の位置５１～５４のそれぞれにおいて、手先２が平面治具７により拘束された状態で、エンコーダ６の値を取得する。補正部４２は、取得部４１により取得されたエンコーダ６の値を用いて、多関節ロボット３１の機構誤差を算出し、補正する。 As shown in FIG. 2, the control unit 40 includes an acquisition unit 41 and a correction unit 42. The acquiring unit 41 acquires the value of the encoder 6 in a state in which the hand 2 is restrained by the planar jig 7 at each of the four positions 51 to 54 on the surface of the planar jig 7. The correction unit 42 calculates and corrects a mechanism error of the articulated robot 31 using the value of the encoder 6 acquired by the acquisition unit 41.
　図１に示す多関節ロボット３１の動作について、図３を用いて説明する。図３は、本実施の形態１における多関節ロボット３１の機構誤差の補正方法を示すフローチャートである。 The operation of the articulated robot 31 shown in FIG. 1 will be described with reference to FIG. FIG. 3 is a flowchart showing a method of correcting a mechanical error of the articulated robot 31 according to the first embodiment.
　まず、取得部４１は、平面治具７の表面の４箇所の異なる位置５１～５４のそれぞれにおいて、多関節ロボット３１の手先２を拘束した状態で、多関節ロボット３１の関節１ａの角度を取得する（ステップＳ０１：取得工程）。 First, the acquiring unit 41 acquires the angle of the joint 1 a of the articulated robot 31 in a state in which the hand 2 of the articulated robot 31 is restrained at each of four different positions 51 to 54 on the surface of the plane jig 7. (Step S01: acquisition step).
　次に、補正部４２は、ステップＳ０１の取得工程において取得された多関節ロボット３１の関節１ａの角度を用いて、多関節ロボット３１の機構誤差を算出して補正する（ステップＳ０２：補正工程）。 Next, the correction unit 42 calculates and corrects a mechanical error of the articulated robot 31 using the angle of the joint 1a of the articulated robot 31 acquired in the acquisition step of step S01 (step S02: correction step) .
　図４は、本実施の形態１における多関節ロボット３１の機構誤差の補正方法の具体的な一例を示すフローチャートである。 FIG. 4 is a flowchart showing a specific example of a method of correcting a mechanical error of the articulated robot 31 according to the first embodiment.
　まず、取得部４１は、インデックスｉを設定し、このインデックスｉをｉ＝１に初期化する（ステップＳ１１）。インデックスｉは、本実施の形態１では、ｉ＝１が第一の位置５１に定義され、ｉ＝２が第二の位置５２に定義され、ｉ＝３が第三の位置５３に定義され、ｉ＝４が第四の位置５４に定義されている。また、本実施の形態１では、少なくとも４箇所の異なる位置５１～５４で多関節ロボット３１の関節１ａの角度を取得すればよいため、ｉ＝４までを用いた場合について説明する。 First, the acquisition unit 41 sets an index i, and initializes the index i to i = 1 (step S11). In the first embodiment, the index i is defined such that i = 1 at the first position 51, i = 2 at the second position 52, and i = 3 at the third position 53. i = 4 is defined in the fourth position 54. Further, in the first embodiment, since it is sufficient to acquire the angles of the joints 1a of the articulated robot 31 at at least four different positions 51 to 54, the case of using i up to 4 will be described.
　続いて、取得部４１は、インデックスｉ＝１で定義された第一の位置５１（図１の（ａ）に示す平面治具７の表面の位置）において、手先２の平面接触部８を平面治具７の表面に押し付けて、手先２の角度が平面治具７の法線方向と同じになるように手先２の姿勢を拘束する。そして、その状態で、取得部４１は、エンコーダ６の値θｉを取得して、記憶する（ステップＳ１２）。 Subsequently, the acquiring unit 41 planarizes the plane contact portion 8 of the hand 2 at the first position 51 (the position of the surface of the plane jig 7 shown in FIG. 1A) defined by the index i = 1. The posture of the hand 2 is restrained such that the angle of the hand 2 is pressed to the surface of the jig 7 so that the angle of the hand 2 becomes the same as the normal direction of the plane jig 7. Then, in that state, the acquisition unit 41 acquires and stores the value θi of the encoder 6 (step S12).
　次に、取得部４１は、インデックスｉが４以上であるか否か、すなわちｉ≧４を判定する（ステップＳ１３）。 Next, the acquisition unit 41 determines whether the index i is 4 or more, that is, ii4 (step S13).
　インデックスｉが４未満の場合（ステップＳ１３のＮｏ）、インデックスｉを１増やして、ｉ＝ｉ＋１とする（ステップＳ１４）。その後、ステップＳ１２、Ｓ１３を実行する。 If the index i is less than 4 (No in step S13), the index i is incremented by 1 to be i = i + 1 (step S14). Thereafter, steps S12 and S13 are performed.
　つまり、ステップＳ１２～ステップＳ１４を繰り返すことにより、取得部４１は、平面治具７の表面の４つの任意の異なる位置５１～５４のそれぞれにおいて、手先２の角度が平面治具７の表面の法線方向と同じになるように手先２の姿勢が拘束された状態で、その状態におけるエンコーダ６の値θ１～θ４を取得して、記憶する。このステップＳ１１～ステップＳ１５が、ステップＳ０１の取得工程の一例である。 That is, by repeating step S12 to step S14, the acquiring unit 41 determines that the angle of the tip 2 of the four arbitrary positions 51 to 54 on the surface of the plane jig 7 is the method of the surface of the plane jig 7 In a state in which the posture of the hand 2 is constrained so as to be the same as the linear direction, values θ1 to θ4 of the encoder 6 in that state are acquired and stored. Steps S11 to S15 are an example of the acquisition process of step S01.
　そして、インデックスｉが４以上の場合（ステップＳ１３のＹｅｓ）、４箇所の異なる位置５１～５４のそれぞれで取得した４つのエンコーダ６の値θ１～θ４を用いて、以下の計算を行って機構誤差を算出し、算出された機構誤差を補正する（ステップＳ１５）。このステップＳ１５が、ステップＳ０２の補正工程の一例である。 Then, if the index i is 4 or more (Yes in step S13), the following calculation is performed using the values θ1 to θ4 of the four encoders 6 acquired at each of the four different positions 51 to 54, and the mechanism error Is calculated, and the calculated mechanism error is corrected (step S15). This step S15 is an example of the correction process of step S02.
　ステップＳ１５について、説明する。ステップＳ１５は、取得したエンコーダ６の値θｉから、本実施の形態１の機構誤差を算出する計算である。本実施の形態１の機構誤差の一例は、リンク３の長さＬの誤差である。本実施の形態１の多関節ロボット３１において、アーム４の角度と手先２の位置及び姿勢との関係を表す運動学方程式は、（式１）であり、Ｐｉ、θｉ、Ｌの変数で表される関数Ｆ１として導かれる。 Step S15 will be described. Step S15 is calculation to calculate the mechanism error of the first embodiment from the obtained value θi of the encoder 6. An example of the mechanism error according to the first embodiment is an error of the length L of the link 3. In the articulated robot 31 according to the first embodiment, the kinematics equation representing the relationship between the angle of the arm 4 and the position and posture of the hand 2 is (Equation 1), and is expressed by variables P i , θ i and L. It is derived as the represented function F1.
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　（式１）は６次元の式である。ここで、Ｐｉ＝（Ｘｉ，Ｙｉ，Ｚｉ，θｘｉ，θｙｉ，θｚｉ）は、手先２の位置及び姿勢を表す６次元ベクトルである。なお、Ｆ１は、パラレルリンクロボットの一般的な運動学方程式であるため、詳細な説明は省略する。また、Ｐｉは未知の値であり、今後の計算により求める。 (Expression 1) is a six-dimensional expression. Here, P i = (X i , Y i , Z i , θ xi , θ yi , θ zi ) is a six-dimensional vector representing the position and posture of the hand 2. In addition, since F1 is a general kinematics equation of a parallel link robot, the detailed description is omitted. Also, P i is an unknown value, which is obtained by calculation in the future.
　θｉ＝（θ１ｉ，θ２ｉ，θ３ｉ，θ４ｉ，θ５ｉ，θ６ｉ）は、多関節ロボット３１のそれぞれのモータ５のエンコーダ６の値である６次元ベクトルである。つまり、θｉは、平面治具７の４箇所の異なる位置５１～５４において手先２を拘束することにより取得された値である。Ｌ＝（Ｌ１，Ｌ２，Ｌ３，Ｌ４，Ｌ５，Ｌ６）は、補正対象の６本のリンク３の長さを示しており、６次元ベクトルである。 θ i = (θ1 i, θ2 i, θ3 i, θ4 i, θ5 i, θ6 i) is a six-dimensional vector are the respective values of the encoder 6 of the motor 5 of the articulated robot 31. That is, θ i is a value obtained by restraining the hand 2 at four different positions 51 to 54 of the plane jig 7. L = (L1, L2, L3, L4, L5, L6) indicates the length of six links 3 to be corrected, and is a six-dimensional vector.
　本実施の形態１では、リンク３の長さＬは、未知の値である。本実施の形態１では、今後の計算により、このリンク３の長さＬの値を求めることで、リンク３の長さＬの誤差を算出して補正する。なお、本実施の形態１では、リンク３の長さＬ以外の多関節ロボット３１の機構寸法は、設計値と同じであると仮定している。以下の説明により求めるリンク３の実際の長さＬは、計測値の一例である。 In the first embodiment, the length L of the link 3 is an unknown value. In the first embodiment, the error of the length L of the link 3 is calculated and corrected by calculating the value of the length L of the link 3 by calculation from now on. In the first embodiment, it is assumed that the mechanical dimensions of the articulated robot 31 other than the length L of the link 3 are the same as the design values. The actual length L of the link 3 determined by the following description is an example of the measurement value.
　ここで、４箇所の異なる位置５１～５４での多関節ロボット３１の手先２の姿勢が、それぞれの位置５１～５４において同一の方向（平面治具７の法線方向）に拘束された状態にあるため、次の（式２）に示すとおり、Ｐｉ、α、βの変数で表される関数Ｎが導かれる。つまり、実施の形態１において手先２の姿勢が拘束状態であることを示す関係は、（式２）の関数Ｎとして導かれる。 Here, the posture of the tip 2 of the articulated robot 31 at four different positions 51 to 54 is constrained in the same direction (the normal direction of the plane jig 7) at each of the positions 51 to 54. Therefore, as shown in the following (Equation 2), a function N represented by variables P i , α, β is derived. That is, in the first embodiment, the relationship indicating that the posture of the hand 2 is in the constrained state is derived as the function N of (Expression 2).
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
　（式２）は２次元の式であり、Ｐｉは（式１）と同じである。また、α及びβは、平面治具７の法線の方向を表す値である。 (Expression 2) is a two-dimensional expression, and P i is the same as (Expression 1). Further, α and β are values representing the direction of the normal of the plane jig 7.
　なお、ここで、多関節ロボット３１の手先２の座標系から固定座標系への変換行列は、（式３）のように表される。 Here, the transformation matrix from the coordinate system of the hand 2 of the articulated robot 31 to the fixed coordinate system is expressed as (Expression 3).
Figure JPOXMLDOC01-appb-M000003
Figure JPOXMLDOC01-appb-M000003
　（式３）において、Ｘｈ、Ｙｈ及びＺｈは手先２の座標系における位置を表し、Ｘｂ、Ｙｂ及びＺｂは固定座標系に変換した後の位置を表す。ここで、所定の条件で単位ベクトル変換を行うことを考える場合、次の（式４）を導くことができる。所定の条件とは、多関節ロボット３１の手先２の座標系におけるＺ方向の単位ベクトルが、平面治具７の表面の法線方向に拘束されており、手先座標系のＺ軸回りの回転が、拘束されていないという条件である。 In Equation (3), X h , Y h and Z h represent the position of the hand 2 in the coordinate system, and X b , Y b and Z b represent the position after conversion to the fixed coordinate system. Here, when considering performing unit vector conversion under predetermined conditions, the following (Expression 4) can be derived. The predetermined condition is that the unit vector in the Z direction in the coordinate system of the hand 2 of the articulated robot 31 is constrained in the normal direction of the surface of the plane jig 7 and the rotation of the hand coordinate system around the Z axis is , Not constrained.
Figure JPOXMLDOC01-appb-M000004
Figure JPOXMLDOC01-appb-M000004
　ここで、α、β、γは、単位ベクトルであるため、α２＋β２＋γ２＝１の関係が成り立つ。この関係を用いることで、（式４）においてγを消去することができ、次の（式５）の２式を導くことができる。 Here, since α, β and γ are unit vectors, the relationship of α 2 + β 2 + γ 2 = 1 holds. By using this relationship, γ can be eliminated in (Equation 4), and the following two (Equation 5) equations can be derived.
Figure JPOXMLDOC01-appb-M000005
Figure JPOXMLDOC01-appb-M000005
　　（式５）において、α、βは未知の値であり、今後の計算により値を求める。 In Equation (5), α and β are unknown values, and values will be obtained by calculation in the future.
　さらに、４箇所の異なる位置５１～５４での多関節ロボット３１の手先２は、平面治具７で同一平面上にあるため、次の（式６）が導かれる。 Furthermore, since the tips 2 of the articulated robot 31 at four different positions 51 to 54 are on the same plane by the plane jig 7, the following (Expression 6) is derived.
Figure JPOXMLDOC01-appb-M000006
Figure JPOXMLDOC01-appb-M000006
　（式６）は１次元の式であり、Ｘｉ，Ｙｉ，Ｚｉは、Ｐｉの位置を示すＸ軸方向、Ｙ軸方向、及びＺ軸方向の３方向の成分である。ａ，ｂ，ｃ，ｄは、３次元空間上で平面を表す未知の値であり、今後の計算により求める。 Equation (6) is a one-dimensional equation, and X i , Y i and Z i are components in three directions of the X-axis direction, the Y-axis direction, and the Z-axis direction, which indicate the position of P i . a, b, c, d are unknown values representing a plane in a three-dimensional space, and are obtained by calculation in the future.
　なお、（式５）は、平面治具７の４箇所の異なる位置５１～５４における法線方向の姿勢を示す関係式であり、（式６）は、平面治具７の表面である平面の４箇所の異なる位置５１～５４を示す関係式である。 (Expression 5) is a relational expression showing the posture in the normal direction at four different positions 51 to 54 of the plane jig 7, and (Expression 6) is a plane of the surface of the plane jig 7. It is a relational expression showing four different positions 51-54.
　インデックスｉがｉ＝１～４の４つの場合において各エンコーダ６の値が得られるため、（式１）、（式５）及び（式６）について４個ずつの式が得られる。つまり、（式１）の６次元式が４個であり、（式５）の２次元式が４個であり、（式６）の１次元式が４個であることから、４つのエンコーダθｉに基づいて３６個（６次元×４個＋２次元×４個＋１次元×４個）の連立方程式が得られる。未知数は、Ｐｉを構成するＸｉ、Ｙｉ、Ｚｉ、θｘｉ、θｙｉ及びθｚｉ（ｉ＝１～４）の２４個（６次元×４個）と、Ｌを構成するＬ１、Ｌ２、Ｌ３、Ｌ４、Ｌ５及びＬ６の６個と、α、β、ａ、ｂ、ｃ、及びｄの６個と、の計３６個である。上記の３６個の連立方程式を例えばニュートン法などによる数値解析により計算することで、３６個の未知のパラメータを求めることができる。これによりリンク３の長さＬの計測値が求められる。求めたリンク３の長さＬの計測値をリンク３の設計値と比較することで、リンク３の長さＬの誤差を算出することができる。そして、このリンク３の長さＬの誤差を補正することで、多関節ロボット３１の機構誤差の補正を行うことができる。 Since the value of each encoder 6 is obtained when the index i is four in the case of i = 1 to 4, four equations are obtained for each of (Equation 1), (Equation 5) and (Equation 6). That is, since there are four six-dimensional expressions of (Expression 1), four two-dimensional expressions of (Expression 5), and four one-dimensional expressions of (Expression 6), four encoders θi 36 (6 dimensions x 4 + 2 dimensions x 4 + 1 dimensions x 4) simultaneous equations are obtained. The unknowns are 24 (6 dimensions × 4) of X i , Y i , Z i , θ xi , θ yi and θ zi (i = 1 to 4) constituting P i and L 1 constituting L There are a total of 36 of six L2, L3, L4, L5 and L6 and six of α, β, a, b, c and d. The 36 unknown parameters can be determined by calculating the above 36 simultaneous equations by numerical analysis using, for example, the Newton method. Thus, a measurement value of the length L of the link 3 is obtained. By comparing the obtained measurement value of the length L of the link 3 with the design value of the link 3, an error of the length L of the link 3 can be calculated. Then, by correcting the error of the length L of the link 3, it is possible to correct the mechanical error of the articulated robot 31.
　本実施の形態１によれば、多関節ロボット３１の機構誤差の補正に平面治具７の表面を用いているため、プレートの穴を用いる従来の機構誤差の補正の場合と比較して、温度変化に対する状態の変化が生じにくい。これは、平面形状を有する平面治具７が温度変化により膨張又は収縮した場合、従来の機構誤差の補正に用いた穴間の距離は変化するが、本実施の形態１の機構誤差の補正に用いた表面の形状は変化しにくいためである。そのため、本実施の形態１の多関節ロボットの機構誤差の補正方法を用いることで、温度変化に対し精度が低下する可能性が低い多関節ロボットの機構誤差の補正を、行うことができる。 According to the first embodiment, since the surface of the plane jig 7 is used to correct the mechanical error of the articulated robot 31, the temperature is higher than that of the conventional correction of the mechanical error using the holes of the plate. It is hard for the change of the state to change to occur. This is because, when the planar jig 7 having a planar shape expands or contracts due to a temperature change, the distance between the holes used for the correction of the conventional mechanism error changes, but the mechanism error of the first embodiment is corrected. It is because the shape of the used surface does not change easily. Therefore, by using the method of correcting mechanical errors of the articulated robot according to the first embodiment, it is possible to correct mechanical errors of the articulated robot which is less likely to decrease in accuracy with respect to temperature change.
　なお、手先２の平面接触部８を押し付ける平面治具７の表面における４箇所の位置は、任意の異なる位置でよいが、それぞれの位置で多関節ロボット３１の姿勢が変化する４箇所である必要がある。なお、本実施の形態１の多関節ロボット３１はパラレルリンクロボットであるため、平面治具７の表面における４箇所の位置は、ロボットの中心からの距離が異なる位置であることが望ましい。また、この４箇所の異なる位置５１～５４は、それぞれの間の距離がおよそ均等に離れた位置としてもよい。これらにより、機構誤差の補正精度をより高めることができる。 Although the four positions on the surface of the plane jig 7 pressing the plane contact portion 8 of the hand 2 may be any different positions, it is necessary that the positions of the articulated robot 31 change at each position. There is. In addition, since the articulated robot 31 of the first embodiment is a parallel link robot, it is preferable that the four positions on the surface of the plane jig 7 be positions different in distance from the center of the robot. Further, the four different positions 51 to 54 may be positions at which the distances between the respective positions are approximately equal. By these, the correction | amendment precision of a mechanism error can be raised more.
　なお、「多関節ロボット３１の姿勢が変化する」とは、１つ以上の関節１ａ，１ｂ，１ｃの角度が変化することを指す。 Note that "the posture of the articulated robot 31 changes" indicates that the angles of one or more joints 1a, 1b, and 1c change.
　なお、４箇所の異なる位置５１～５４は、具体的には、多関節ロボット３１の可動範囲内で互いの距離が可能な限り長くなるようにした位置であって、４箇所を結んだ形状が正方形の形状としてもよい。 Specifically, the four different positions 51 to 54 are positions where the mutual distance is as long as possible within the movable range of the articulated robot 31, and the shape connecting the four is It may be a square shape.
　なお、本実施の形態１において、平面治具７の表面の形状を基台２１に対して平行な平面で説明したが、基台２１に対して、傾いた平面であっても上記の（式１）、（式５）及び（式６）を用いた機構誤差の補正方法を適用できる。 In the first embodiment, the shape of the surface of the plane jig 7 is described as a plane parallel to the base 21. However, even if the plane is inclined with respect to the base 21, the above-mentioned (formula 1) The correction method of the mechanism error using equation (5) and equation (6) can be applied.
　また、本実施の形態１に係る多関節ロボットの機構誤差の補正方法では、平面治具７の表面における４箇所の異なる位置５１～５４において手先２を拘束した状態で測定することで解が求めることができるが、平面治具７に拘束される位置が４箇所より少ない場合は一意的に解を求めることができない。 Further, in the method of correcting mechanical errors of the articulated robot according to the first embodiment, the solution is obtained by measuring with the hand 2 restrained at four different positions 51 to 54 on the surface of the plane jig 7 However, if the number of positions constrained by the planar jig 7 is less than four, the solution can not be uniquely determined.
　なお、４箇所よりも多い５箇所以上の位置において手先２を平面治具７の表面に拘束した状態で測定することにより得られた値に対して最小二乗法や平均などを用いることで、さらに機構誤差の補正精度を高めることができる。 In addition, by using the method of least squares or the average with respect to the value obtained by measuring in a state in which the hand 2 is restrained to the surface of the plane jig 7 at five or more positions more than four, It is possible to enhance the correction accuracy of the mechanism error.
　（実施の形態２）
　図５は、本発明の実施の形態２に係る多関節ロボット３２の姿勢を示す図である。図５の（ａ）は球面治具９の第一の位置６１における姿勢を示す図であり、図５の（ｂ）は球面治具９の第二の位置６２における姿勢を示す図であり、図５の（ｃ）は球面治具９の第三の位置６３における姿勢を示す図であり、図５の（ｄ）は球面治具９の第四の位置６４における姿勢を示す図である。第一の位置６１、第二の位置６２、第三の位置６３及び第四の位置６４は、球面治具９の表面のそれぞれ互いに異なる位置である。 Second Embodiment
FIG. 5 is a view showing the posture of an articulated robot 32 according to Embodiment 2 of the present invention. FIG. 5A is a view showing the attitude of the spherical jig 9 at the first position 61, and FIG. 5B is a view showing the attitude of the spherical jig 9 at the second position 62. FIG. 5C shows the attitude of the spherical jig 9 at the third position 63, and FIG. 5D shows the attitude of the spherical jig 9 at the fourth position 64. As shown in FIG. The first position 61, the second position 62, the third position 63 and the fourth position 64 are positions different from each other on the surface of the spherical jig 9.
　図５に示すように、本実施の形態２に係る多関節ロボット３２の構成要素は、図１の平面接触部８を球面接触部１０に置き換えた以外は図１の多関節ロボット３１と同じであるため、適宜説明を省略する。 As shown in FIG. 5, the components of the articulated robot 32 according to the second embodiment are the same as the articulated robot 31 of FIG. 1 except that the flat contact portion 8 of FIG. Since there is a description, the description will be omitted appropriately.
　また、実施の形態２に係る多関節ロボット３２の機構誤差の補正は、表面が球面である球面治具９を用いて行う。球面治具９は、多関節ロボット３２の基台２１との位置関係が変化しないように固定されている。 The correction of the mechanical error of the articulated robot 32 according to the second embodiment is performed using a spherical jig 9 whose surface is a spherical surface. The spherical jig 9 is fixed so that the positional relationship between the articulated robot 32 and the base 21 does not change.
　手先２に固定された球面接触部１０は、球面治具９と同じ半径の凹面（凹型の曲面）を有する。ここで、球面接触部１０の凹面は球面治具９と隙間なく接触できる面である。球面接触部１０は、最低限、球面治具９に接触したときの姿勢及び位置が一意的に決まるような形状であればよい。球面接触部１０は、例えば中空の円筒形状であってもよいが、球面治具９と確実に接触させるためには、図５に図示したような凹型の曲面を有する球面接触部１０が望ましい。球面接触部１０は、接触部の一例である。球面治具９は、治具の一例であり、その表面が球面で構成されている。 The spherical contact portion 10 fixed to the hand 2 has a concave surface (concave curved surface) of the same radius as the spherical jig 9. Here, the concave surface of the spherical contact portion 10 is a surface that can contact the spherical jig 9 without a gap. The spherical contact portion 10 may have at least a shape that uniquely determines an attitude and a position when contacting the spherical jig 9. The spherical contact portion 10 may be, for example, a hollow cylindrical shape, but in order to ensure contact with the spherical jig 9, the spherical contact portion 10 having a concave curved surface as shown in FIG. 5 is desirable. The spherical contact portion 10 is an example of the contact portion. The spherical jig 9 is an example of a jig, and the surface thereof is formed of a spherical surface.
　このような多関節ロボット３２の機構誤差の補正を行う場合、球面治具９の表面の４箇所の異なる位置６１～６４に手先２の球面接触部１０を接触させて、４箇所の異なる位置６１～６４における法線方向に対する手先２の角度がそれぞれ同一となるように、球面治具９により手先２の姿勢が拘束された状態とする。具体的には、図５の（ａ）、（ｂ）、（ｃ）及び（ｄ）に示すように、４箇所の異なる位置６１～６４において、手先２の球面接触部１０を球面治具９の表面である球面に押し付けることにより、手先２の手先座標系での球面接触部１０の球面の中心位置が４箇所の異なる位置６１～６４のそれぞれで球面治具９の球面の中心と一致するように拘束する。つまり、手先２は、手先座標系における所定の方向に延びる軸（例えばＺ軸）が常に球面治具９の球面の中心と一致するように、球面接触部１０により固定されることになる。このようにして、手先２の球面接触部１０が球面治具９により拘束された後、４箇所の異なる位置６１～６４のそれぞれにおいて、エンコーダ６の値を取得して、記憶する。なお、本実施の形態２に係る多関節ロボット３２の機構誤差の補正方法の処理は、計算式以外が実施の形態１に係る多関節ロボットの機構誤差の補正方法の処理と同様であるため、処理の説明は省略する。 When correcting the mechanical error of the multi-joint robot 32 as described above, the spherical contact portion 10 of the hand 2 is brought into contact with four different positions 61 to 64 of the surface of the spherical jig 9 to obtain four different positions 61. The posture of the hand 2 is restrained by the spherical jig 9 so that the angles of the hand 2 with respect to the normal direction in the range of to 64 are the same. Specifically, as shown in (a), (b), (c) and (d) of FIG. 5, the spherical contact portion 10 of the hand 2 is spherical jig 9 at four different positions 61 to 64. The center position of the spherical surface of the spherical contact portion 10 in the hand 2 coordinate system of the hand 2 coincides with the center of the spherical surface of the spherical jig 9 at each of four different positions 61 to 64 Restrain as. That is, the hand 2 is fixed by the spherical contact portion 10 so that an axis (for example, Z axis) extending in a predetermined direction in the hand coordinate system always coincides with the center of the spherical surface of the spherical jig 9. Thus, after the spherical surface contact portion 10 of the hand 2 is restrained by the spherical surface jig 9, the value of the encoder 6 is obtained and stored at each of the four different positions 61 to 64. The processing of the method of correcting mechanical errors of the articulated robot 32 according to the second embodiment is the same as the processing of the method of correcting mechanical errors of the articulated robot according to the first embodiment except for the calculation formula. The description of the process is omitted.
　次に、取得したエンコーダ６の値からの計算の内容を説明する。図５に示す本実施の形態２の多関節ロボット３２において、アーム４の角度と手先２の位置及び姿勢との関係を表す運動学方程式は、図１に示す実施の形態１の多関節ロボット３１の場合と同様に、前述の（式１）である。ここで、Ｐｉ、θｉ及びＬは実施の形態１の場合と同じであり、インデックスｉ＝１～４である。 Next, the contents of calculation from the value of the acquired encoder 6 will be described. In the multi-joint robot 32 of the second embodiment shown in FIG. 5, the kinematics equation representing the relationship between the angle of the arm 4 and the position and posture of the hand 2 is the multi-joint robot 31 of the first embodiment shown in FIG. In the same manner as in the above, (Equation 1) described above. Here, P i , θ i and L are the same as in the case of the first embodiment, and the index i is 1 to 4.
　本実施の形態２では、４箇所の異なる位置６１～６４のそれぞれにおいて、手先２の球面接触部１０の球面の中心が球面治具９の中心と一致することから、（式７）のように、Ｐｉ、Ｔ及びＢの変数で表される関数Ｇが導かれる。つまり、実施の形態２において手先２の姿勢が拘束状態であることを示す関係は、（式７）の関数Ｇとして導かれる。 In the second embodiment, since the center of the spherical surface of the spherical contact portion 10 of the hand 2 coincides with the center of the spherical jig 9 at each of the four different positions 61 to 64, as shown in equation (7) , P i , T and B variables G are derived. That is, in the second embodiment, the relationship indicating that the posture of the hand 2 is in the restricted state is derived as a function G of (Expression 7).
Figure JPOXMLDOC01-appb-M000007
Figure JPOXMLDOC01-appb-M000007
　（式７）は３次元の式である。Ｔ＝（Ｔｘ，Ｔｙ，Ｔｚ）は、手先２の球面接触部１０の球面の中心の位置を表す３次元ベクトルである。Ｔは未知の値であり、今後の計算により求められる。Ｂ＝（Ｂｘ，Ｂｙ，Ｂｚ）は、多関節ロボット３２の固定座標系における球面治具９の中心座標を表す３次元ベクトルである。Ｂは未知の値であり、今後の計算により求められる。 (Expression 7) is a three-dimensional expression. T = (T x , T y , T z ) is a three-dimensional vector representing the position of the center of the spherical surface of the spherical contact portion 10 of the hand 2. T is an unknown value, which can be calculated by a future calculation. B = (Bx, By, Bz) is a three-dimensional vector representing the central coordinates of the spherical jig 9 in the fixed coordinate system of the articulated robot 32. B is an unknown value, which can be obtained by calculation in the future.
　ここで、（式７）のＧを具体的に表すと、次の（式８）のように表される。（式８）は、手先座標系におけるＴ＝（Ｔｘ，Ｔｙ，Ｔｚ）を固定座標系に変換したＢ＝（Ｂｘ，Ｂｙ，Ｂｚ）が、多関節ロボット３２の手先２の位置及び姿勢によらず一定であるという関係に基づいて表される。 Here, when G in (Equation 7) is specifically represented, it is represented as the following (Equation 8). (Equation 8) is obtained by converting T = (T x , T y , T z ) in the hand coordinate system to a fixed coordinate system, but B = (B x , B y , B z ) is the hand 2 of the articulated robot 32 It is expressed based on the relation that it is constant regardless of the position and posture of
Figure JPOXMLDOC01-appb-M000008
Figure JPOXMLDOC01-appb-M000008
　インデックスｉがｉ＝１～４の４つの場合、（式１）及び（式８）について４個ずつの式が得られる。本実施の形態２では、（式１）の６次元式が４個であり、（式８）の３次元式が４個であるため、３６個（６次元×４個＋３次元×４個）の連立方程式が得られる。未知数は、Ｐｉを構成するＸｉ、Ｙｉ、Ｚｉ、θｘｉ、θｙｉ及びθｚｉ（ｉ＝１～４）の２４個（６次元×４個）と、Ｌを構成するＬ１、Ｌ２、Ｌ３、Ｌ４、Ｌ５及びＬ６の６個と、Ｔを構成するＴｘ、Ｔｙ及びＴｚの３個と、Ｂを構成するＢｘ、Ｂｙ及びＢｚの３個と、の計３６個である。上記の３６個の連立方程式を例えばニュートン法などによる数値解析により計算することで、３６個の未知のパラメータを求めることができる。これによりリンク３の長さＬの計測値を求めることができる。求めたリンク３の長さＬをリンク３の設計値と比較することで、リンク３の長さＬの誤差を算出することができる。そして、このリンク３の長さＬの誤差を補正することで、多関節ロボット３２の機構誤差の補正を行うことができる。 When the index i is four with i = 1 to 4, four equations are obtained for (Equation 1) and (Equation 8). In the second embodiment, there are four six-dimensional expressions of (Expression 1) and four three-dimensional expressions of (Expression 8), so 36 (6 dimensions × 4 + 3 dimensions × 4) Simultaneous equations of are obtained. The unknowns are 24 (6 dimensions × 4) of X i , Y i , Z i , θ xi , θ yi and θ zi (i = 1 to 4) constituting P i and L 1 constituting L A total of six L2, L3, L4, L5 and L6, three T x , T y and T z constituting T, and three B x , B y and B z constituting B It is 36 pieces. The 36 unknown parameters can be determined by calculating the above 36 simultaneous equations by numerical analysis using, for example, the Newton method. Thereby, the measurement value of the length L of the link 3 can be obtained. By comparing the calculated length L of the link 3 with the design value of the link 3, an error of the length L of the link 3 can be calculated. Then, by correcting the error of the length L of the link 3, it is possible to correct the mechanical error of the articulated robot 32.
　本実施の形態２に係る多関節ロボットの機構誤差の補正方法によれば、多関節ロボット３２の手先２を球面治具９の表面の４箇所の異なる位置６１～６４に押し付けることにより、手先２が球面治具９の表面に拘束された状態とし、その状態におけるエンコーダ６の値を用いることで、多関節ロボット３２の機構誤差（リンク３の長さＬについて、設計値と求められた値との差）を計算して補正することができる。本実施の形態２では、多関節ロボット３２の機構誤差の補正を行うために、温度が変化しても変形しにくい球面形状を有する球面治具９を用いている。そのため、温度変化に対し精度が低下する可能性が低い多関節ロボットの機構誤差の補正を行うことができる。 According to the method of correcting mechanical errors of the articulated robot according to the second embodiment, the tip 2 of the articulated robot 32 is pressed against the four different positions 61 to 64 on the surface of the spherical jig 9 so that the tip 2 is moved. Is constrained to the surface of the spherical jig 9 and the value of the encoder 6 in that state is used, the mechanical error of the articulated robot 32 (the design value and the value obtained for the length L of the link 3 ) Can be calculated and corrected. In the second embodiment, in order to correct a mechanical error of the articulated robot 32, a spherical jig 9 having a spherical shape that is not easily deformed even when the temperature changes is used. Therefore, it is possible to correct the mechanical error of the articulated robot which is less likely to reduce the accuracy with respect to the temperature change.
　なお、手先２を押し付ける球面治具９の表面における４箇所の位置は、任意の異なる位置であればよいが、それぞれの位置で多関節ロボット３２の姿勢が互いに変化する４箇所である必要がある。当該４箇所の異なる位置６１～６４はそれぞれの間の距離がおよそ均等に離れており、かつ、当該４箇所の異なる位置６１～６４における手先２の姿勢の角度がそれぞれ可能な限り異なることが、機構誤差の補正精度を高める上で望ましい。 The four positions on the surface of the spherical jig 9 pressing the hand 2 may be any different positions, but the positions of the articulated robot 32 need to be different from one another at each position. . The four different positions 61 to 64 are approximately equally spaced apart from one another, and the angles of the posture of the hand 2 at the four different positions 61 to 64 differ as much as possible, It is desirable to improve the correction accuracy of the mechanism error.
　また、本実施の形態２に係る多関節ロボットの機構誤差の補正方法では、球面治具９の表面における４箇所の異なる位置６１～６４において手先２を拘束した状態で測定することで解が求めることができるが、球面治具９に拘束される位置が４箇所より少ない場合は一意的に解を求めることができない。なお、球面治具９の５箇所以上の位置において、手先２を球面治具９の表面に拘束した状態で測定することにより得られた値を最小二乗法や平均などを用いることで、さらに構成精度を高めることができる。 Further, in the method of correcting mechanical errors of the articulated robot according to the second embodiment, the solution is obtained by measuring with the hand 2 restrained at four different positions 61 to 64 on the surface of the spherical jig 9 However, if the number of positions constrained by the spherical jig 9 is smaller than four, the solution can not be uniquely determined. In addition, the configuration obtained by using the least square method or the average or the like of the value obtained by measuring in a state in which the hand 2 is restrained to the surface of the spherical jig 9 at five or more positions of the spherical jig 9 Accuracy can be improved.
　実施の形態２に係る多関節ロボットの機構誤差の補正方法は、実施の形態１のような大きい平面の平面治具７を設置することが困難な装置に組み込まれた多関節ロボット３２の補正を行う場合に有効である。 The method of correcting mechanical errors of the articulated robot according to the second embodiment includes the correction of the articulated robot 32 incorporated in an apparatus in which it is difficult to install the large plane flat jig 7 as in the first embodiment. It is effective when doing.
　（実施の形態３）
　図６は、本発明の実施の形態３に係る多関節ロボット３３の姿勢を示す図であって、図６の（ａ）は平面治具７の第一の位置７１における姿勢を示す図であり、図６の（ｂ）は平面治具７の第二の位置７２における姿勢を示す図であり、図６の（ｃ）は平面治具７の第三の位置７３における姿勢を示す図であり、図６の（ｄ）は平面治具７の第四の位置７４における姿勢を示す図である。なお、第一の位置７１、第二の位置７２、第三の位置７３及び第四の位置７４は、平面治具７の表面上のそれぞれ互いに異なる位置である。 Third Embodiment
FIG. 6 is a view showing the attitude of the articulated robot 33 according to Embodiment 3 of the present invention, and FIG. 6 (a) is a view showing the attitude of the plane jig 7 at the first position 71. 6 (b) shows the attitude of the plane jig 7 at the second position 72, and FIG. 6 (c) shows the attitude of the plane jig 7 at the third position 73. FIG. 6D is a view showing the attitude of the plane jig 7 at the fourth position 74. As shown in FIG. The first position 71, the second position 72, the third position 73, and the fourth position 74 are positions different from each other on the surface of the plane jig 7.
　図６に示すように、実施の形態３に係る多関節ロボット３３は、実施の形態１に係る多関節ロボット３１及び実施の形態２に係る多関節ロボット３２のパラレルリンクロボットとは異なり、シリアルリンクロボットである。 As shown in FIG. 6, the articulated robot 33 according to the third embodiment is different from the articulated robot 31 according to the first embodiment and the parallel link robot of the articulated robot 32 according to the second embodiment, and is a serial link. It is a robot.
　多関節ロボット３３は、手先１２と、ロボット固定部１８と、手先１２及びロボット固定部１８を接続する６本のリンク１３とを有する。手先１２及びロボット固定部１８は、６本のリンク１３により直列に接続されている。手先１２はリンク１３の一つに固定され、６本のリンク１３及びロボット固定部１８はそれぞれ６個の関節１１により接続されている。この６個の関節１１にそれぞれ設けられた６個のモータ１４により、手先１２は６自由度の動作を行うことができる。また、モータ１４は関節角度検出手段としてのエンコーダ１５を備えており、このエンコーダ１５を用いて各関節１１の角度を検出することができる。また、手先１２には、平面治具７の表面に押し付けられたときに、手先１２の姿勢を平面治具７の表面に対して常に同じ姿勢となるように安定させるための平面接触部１６が固定されている。平面接触部１６は、接触部の一例である。 The articulated robot 33 has a hand 12, a robot fixing unit 18, and six links 13 connecting the hand 12 and the robot fixing unit 18. The hand 12 and the robot fixing portion 18 are connected in series by six links 13. The hand 12 is fixed to one of the links 13, and the six links 13 and the robot fixing portion 18 are connected by six joints 11 respectively. The hand 12 can perform an operation with six degrees of freedom by the six motors 14 provided to the six joints 11, respectively. Further, the motor 14 is provided with an encoder 15 as joint angle detection means, and the angle of each joint 11 can be detected using this encoder 15. Further, the hand contact 12 has a flat contact portion 16 for stabilizing the posture of the hand 12 so as to always be the same posture with respect to the surface of the plane jig 7 when pressed against the surface of the plane jig 7. It is fixed. The flat contact portion 16 is an example of the contact portion.
　つまり、平面接触部１６が平面治具７に押し付けられることで、手先１２の位置及び姿勢は、実施の形態１に係る多関節ロボット３１の手先２と同様に平面治具７により拘束される。平面接触部１６は、底面が正方形の直方体であるが、天面と底面とが平行であると共に手先１２が平面治具７の平面である表面に対して平行に面接触するものであれば、その形状は限定されない。なお、平面治具７は、多関節ロボット３３のロボット固定部１８との位置関係が変化しないように固定されている。 That is, when the flat contact portion 16 is pressed against the flat jig 7, the position and posture of the hand 12 are restrained by the flat jig 7 in the same manner as the hand 2 of the articulated robot 31 according to the first embodiment. The flat contact portion 16 is a rectangular solid whose bottom is a square, but if the top and bottom surfaces are parallel and the tip 12 is in plane contact with the flat surface of the flat jig 7 in parallel, The shape is not limited. The flat jig 7 is fixed so that the positional relationship between the articulated robot 33 and the robot fixing unit 18 does not change.
　以上のような構成により、実施の形態１と同様の方法で、図６に示すように、平面治具７の表面の４箇所の異なる位置７１～７４において、手先１２の姿勢及び位置を平面治具７に拘束させることにより取得されたエンコーダ１５の値を用いて、多関節ロボット３３の機構誤差の補正を行うことができる。なお、本実施の形態３に係る多関節ロボット３３の機構誤差の補正方法の処理は、計算式以外が実施の形態１に係る多関節ロボット３１の機構誤差の補正方法の処理と同様であるため、処理の流れの説明は省略する。 With the above configuration, in the same manner as in the first embodiment, as shown in FIG. 6, the posture and position of the tip 12 are planarized at four different positions 71 to 74 on the surface of the planar jig 7. The mechanical error of the articulated robot 33 can be corrected using the value of the encoder 15 acquired by restraining the tool 7. The process of the method of correcting the mechanical error of the articulated robot 33 according to the third embodiment is the same as the process of the method of correcting the mechanical error of the articulated robot 31 according to the first embodiment except for the calculation formula. The description of the process flow is omitted.
　次に、取得したエンコーダ１５の値からの計算の内容を説明する。図６に示す本実施の形態３の多関節ロボット３３における、モータ１４の角度と手先１２の位置及び姿勢との関係を表す運動学方程式は、（式９）に示すとおり、Ｐｉ、θｉ、Ｋの変数で表される関数Ｆ２として導かれる。 Next, the contents of calculation from the value of the acquired encoder 15 will be described. The kinematics equation representing the relationship between the angle of the motor 14 and the position and posture of the hand 12 in the articulated robot 33 according to the third embodiment shown in FIG. 6 is P i , θ i as shown in (Expression 9) , And is derived as a function F2 represented by variables.
Figure JPOXMLDOC01-appb-M000009
Figure JPOXMLDOC01-appb-M000009
　（式９）は６次元の式である。Ｐｉ＝（Ｘｉ，Ｙｉ，Ｚｉ，θｘｉ，θｙｉ，θｚｉ）は手先１２の位置及び姿勢を表す６次元ベクトルであり、ｉ（ｉ＝１～４の整数）は４箇所での手先を示すインデックスである。Ｐｉは未知の値であり、今後の計算により求められる。 Equation (9) is a six-dimensional equation. P i = (X i , Y i , Z i , θ xi , θ yi , θ zi ) is a six-dimensional vector representing the position and posture of the hand 12 and i (i is an integer of 1 to 4) is at four points Is an index that indicates the hand of P i is an unknown value, which can be calculated by a future calculation.
　θｉ＝（θ１ｉ，θ２ｉ，θ３ｉ，θ４ｉ，θ５ｉ，θ６ｉ）は、多関節ロボット３３のそれぞれのモータ１４のエンコーダ１５の値である６次元ベクトルである。つまり、θｉは、平面治具７の４箇所の異なる位置７１～７４において手先２を拘束することにより取得された値であり、既知である。Ｋ＝（Ｋ１，Ｋ２，Ｋ３，Ｋ４，Ｋ５，Ｋ６）は、補正対象である６本のリンク１３の長さ（図６の寸法１７）であり、６次元ベクトルである。Ｋは未知の値であり、今後の計算により求められる。なお、本実施の形態３では、リンク１３の長さＫ以外の多関節ロボット３３の機構寸法は、設計値の理想どおりであると仮定している。 θ i = (θ1 i, θ2 i, θ3 i, θ4 i, θ5 i, θ6 i) is a six-dimensional vector which is the value of the encoder 15 of each motor 14 of the articulated robot 33. That is, θ i is a value acquired by restraining the hand 2 at four different positions 71 to 74 of the plane jig 7 and is known. K = (K1, K2, K3, K4, K5, K6) is the length of the six links 13 to be corrected (dimension 17 in FIG. 6) and is a six-dimensional vector. K is an unknown value, which can be calculated by a future calculation. In the third embodiment, it is assumed that the mechanical dimensions of the articulated robot 33 other than the length K of the link 13 are as ideal as design values.
　また、各４箇所の異なる位置７１～７４での多関節ロボット３３の手先１２の姿勢は、それぞれの位置７１～７４において同一の方向（平面治具７の法線方向）に拘束されている。また、このとき、多関節ロボット３３の手先１２の位置は平面治具７で同一平面上にある。これらの拘束条件から（式５）及び（式６）が実施の形態１と同様に得られる。 Further, the postures of the tips 12 of the articulated robot 33 at four different positions 71 to 74 are constrained in the same direction (the normal direction of the plane jig 7) at the respective positions 71 to 74. At this time, the position of the tip 12 of the articulated robot 33 is on the same plane by the plane jig 7. From these constraint conditions, (Equation 5) and (Equation 6) are obtained as in the first embodiment.
　（式５）、（式６）及び（式９）の連立方程式を数値解析で解くことで、実施の形態１と同様にリンク１３の長さＫを求めることができる。 By solving the simultaneous equations (5), (6) and (9) by numerical analysis, the length K of the link 13 can be determined as in the first embodiment.
　本実施の形態３に係る多関節ロボット３３の機構誤差の補正方法によれば、多関節ロボット３３の手先１２を平面治具７の表面の４箇所の異なる位置７１～７４に押し付けることにより手先１２を平面治具７の表面に拘束された状態とし、その状態におけるエンコーダ１５の値を用いて多関節ロボット３３の機構誤差（リンク１３の長さＫについて、設計値と計測値との差）を計算する。 According to the method of correcting mechanical errors of the articulated robot 33 according to the third embodiment, the tip 12 of the articulated robot 33 is pressed against four different positions 71 to 74 on the surface of the plane jig 7. Of the multi-joint robot 33 (difference between the design value and the measurement value for the length K of the link 13) using the value of the encoder 15 in the state restrained by the surface of the plane jig 7 calculate.
　本実施の形態３でも、多関節ロボット３３の機構誤差の補正を行うために、温度が変化しても変形しにくい平面形状を有する平面治具７を用いている。そのため、温度変化に対して精度が低下する可能性が低くなり、多関節ロボット３３の機構誤差の補正を精度よく行うことができる。 Also in the third embodiment, in order to correct the mechanical error of the articulated robot 33, the flat jig 7 having a planar shape that is not easily deformed even when the temperature changes is used. Therefore, the possibility that the accuracy decreases with respect to the temperature change is reduced, and the mechanical error of the articulated robot 33 can be corrected with high accuracy.
　なお、手先１２を押し付ける平面治具７の表面における４箇所の位置７１～７４は、任意の異なる位置であるが、それぞれの位置で多関節ロボット３３の姿勢が変化する４箇所である必要がある。当該４箇所の異なる位置７１～７４は、それぞれの間の距離がおよそ均等に離れていることが機構誤差の補正精度を高める上で望ましい。 Although the four positions 71 to 74 on the surface of the plane jig 7 pressing the end 12 are any different positions, they need to be four positions at which the posture of the articulated robot 33 changes at each position. . It is desirable that the four different positions 71 to 74 be approximately equally spaced apart from each other in order to improve the correction accuracy of the mechanism error.
　なお、本実施の形態３において、平面治具７の表面の形状をロボット固定部１８が取り付けられている面に対して平行な平面で説明したが、ロボット固定部１８が取り付けられている面に対し、傾いた平面であっても上記の（式５）、（式６）及び（式９）を用いた機構誤差の補正方法を適用できる。 In the third embodiment, the shape of the surface of the flat jig 7 is described as a plane parallel to the surface on which the robot fixing portion 18 is attached, but the surface on which the robot fixing portion 18 is attached is On the other hand, even if it is an inclined plane, the method of correcting a mechanical error using the above (Equation 5), (Equation 6) and (Equation 9) is applicable.
　また、本実施の形態３に係る多関節ロボット３３の機構誤差の補正方法では、平面治具７の表面における４箇所の異なる位置７１～７４において手先１２を拘束した状態で測定することで解を求めることができるが、平面治具７に拘束される位置が４箇所より少ない場合は一意的に解を求めることができない。なお、４箇所よりも多い５箇所以上の位置において手先１２を平面治具７の表面に拘束した状態で測定することにより得られた値を最小二乗法や平均などを用いることで、さらに構成精度を高めることができる。 Further, in the method of correcting mechanical errors of the articulated robot 33 according to the third embodiment, the solution is measured by constraining the hand 12 at four different positions 71 to 74 on the surface of the plane jig 7. Although it can be determined, if the position restrained by the plane jig 7 is less than four, the solution can not be uniquely determined. The configuration accuracy can be further improved by using the method of least squares or averaging the value obtained by measuring with the hand 12 restrained to the surface of the plane jig 7 at five or more positions at four or more positions. Can be enhanced.
　（他の実施の形態１）
　上記実施の形態１～３に係る多関節ロボットの機構誤差の補正方法では、多関節ロボット３１～３３の手先２、１２を、平面治具７又は球面治具９の表面における４箇所の異なる位置５１～５４、６１～６４、７１～７４で拘束した状態で、エンコーダ６、１５の値を取得した。だが、このときに、多関節ロボット３１～３３の手先２、１２を平面治具７又は球面治具９の表面に押し付けて姿勢を拘束した状態で、手先２、１２を移動させながら、エンコーダ６、１５の値を予め定められたタイミング（例えば０．１ｓ間隔のタイミング）で連続的かつ自動的に複数取得するようにしてもよい。このように、多関節ロボット３１～３３の関節の角度であるエンコーダ６、１５の値を取得し記憶する取得工程を、手先２、１２を移動させながら連続的かつ自動的に複数回行うことにより、多関節ロボット３１～３３の機構誤差の補正を容易かつ短時間に実施することができる。ここで、取得工程において記憶される多関節ロボット３１～３３の角度を、多数個（例えば１０００個）取得されたエンコーダ６、１５の値のうちで、手先２、１２が拘束される平面治具７、球面治具９の表面の複数の位置の間の距離がおよそ均等に離れる４箇所における値を用いて計算することにより、より高精度に機構誤差の補正を行うことができる。なお、この場合の手先２、１２が拘束される平面治具７、球面治具９の表面の複数の位置の間の距離がおよそ均等に離れる４箇所は、設計値として予め記憶されている長さＬ、Ｋの値に基づいて導出される手先２の位置に基づいて導出される。 (Other Embodiment 1)
In the method of correcting mechanical errors of the articulated robot according to the first to third embodiments, the hands 2 and 12 of the articulated robots 31 to 33 are at four different positions on the surface of the plane jig 7 or the spherical jig 9. The values of the encoders 6 and 15 were obtained while being constrained by 51 to 54, 61 to 64, and 71 to 74. However, at this time, the encoder 6 is moved while moving the tips 2 and 12 in a state in which the tips 2 and 12 of the articulated robots 31 to 33 are pressed against the surface of the plane jig 7 or the spherical jig 9 and the posture is restrained. Alternatively, a plurality of the fifteen values may be obtained continuously and automatically at predetermined timings (for example, at intervals of 0.1 s). In this manner, the acquisition step of acquiring and storing the values of the encoders 6 and 15 which are angles of the joints of the articulated robots 31 to 33 is continuously and automatically performed a plurality of times while moving the hands 2 and 12. The correction of the mechanical error of the articulated robots 31 to 33 can be easily performed in a short time. Here, among the values of the encoders 6 and 15 acquired in large numbers (for example, 1000), angles of the articulated robots 31 to 33 stored in the acquisition step are planar jigs in which the hands 2 and 12 are restrained. 7. By calculating using values at four points at which the distances between the plurality of positions on the surface of the spherical jig 9 are approximately equally spaced, it is possible to correct the mechanical error with higher accuracy. In this case, four points at which the distance between a plurality of positions on the surface of the plane jig 7 and the surface of the spherical jig 9 at which the tips 2 and 12 are restrained are approximately equally long are stored in advance as design values. It is derived based on the position of the hand 2 derived based on the values of L and K.
　（他の実施の形態２）
　上記実施の形態１、２に係る多関節ロボット３１、３２の機構誤差の補正方法では、リンク３の長さＬの誤差を補正しているが、リンク３の長さだけでなく、アーム４の長さ、手先２の位置を把握するための基準となる手先２上の位置である原点位置（例えば、多関節ロボット３１、３２の電源をＯＦＦにした場合に手先２が収束する位置）の設計値と計測値との誤差の補正についても、同様にして算出することができる。なお、原点位置の誤差の補正については、上記実施の形態３に係る多関節ロボットの機構誤差の補正方法でも適用できる。 (Other embodiment 2)
In the method of correcting mechanical errors of the articulated robots 31 and 32 according to the first and second embodiments, although the error of the length L of the link 3 is corrected, not only the length of the link 3 but the arm 4 Design of an origin position (for example, a position at which the hand 2 converges when the power of the articulated robot 31 or 32 is turned off) which is a position on the hand 2 serving as a reference for grasping the length and the position of the hand 2 The correction of the error between the value and the measurement value can also be calculated in the same manner. The correction of the error of the origin position can also be applied to the method of correcting the mechanical error of the articulated robot according to the third embodiment.
　（他の実施の形態３）
　上記実施の形態１～３に係る多関節ロボットの機構誤差の補正方法では、多関節ロボット３１～３３の駆動機構が電源ＯＦＦの状態で、ユーザが手先２、１２を４箇所の異なる位置５１～５４、６１～６４、７１～７４に移動させてエンコーダ６、１５の値を取得した場合について説明したが、例えば、多関節ロボット３１～３３が自動的に手先２、１２を４箇所の異なる位置５１～５４、６１～６４、７１～７４に移動させてエンコーダ６、１５の値を取得するようにしてもよい。なお、この場合に、手先２、１２が平面治具７、球面治具９に拘束されている状態を多関節ロボット３１～３３が判定する方法としては、押圧センサなどの手先２、１２に対してかかる力の大きさを検出できるセンサを利用することが考えられる。上記の構成により、平面治具７、球面治具９に手先２、１２を押し当てる工程を自動的に行なうことができる。 (Other embodiment 3)
In the method of correcting mechanical errors of the articulated robot according to the first to third embodiments, when the power of the driving mechanism of the articulated robots 31 to 33 is OFF, the user can move the hand tips 2 and 12 at four different positions 51 to Although the case where the values of the encoders 6 and 15 are acquired by moving to 54, 61 to 64, and 71 to 74 has been described, for example, the articulated robots 31 to 33 automatically automatically move hands 2 and 12 to four different positions. The values of the encoders 6 and 15 may be acquired by moving to 51 to 54, 61 to 64, and 71 to 74. In this case, as a method for the multi-joint robots 31 to 33 to determine the state in which the hands 2 and 12 are restrained by the flat jig 7 and the spherical jig 9, the hand 2 and 12 for the pressure sensor or the like is used. It is conceivable to use a sensor capable of detecting the magnitude of such a force. According to the above configuration, the step of pressing the tips 2 and 12 against the flat jig 7 and the spherical jig 9 can be performed automatically.
　以上、本発明の一つまたは複数の態様に係る多関節ロボットの機構誤差の補正方法について、実施の形態に基づいて説明したが、本発明は、この実施の形態に限定されるものではない。本発明の趣旨を逸脱しない限り、当業者が思いつく各種変形を本実施の形態に施したものや、異なる実施の形態における構成要素を組み合わせて構築される形態も、本発明の一つまたは複数の態様の範囲内に含まれてもよい。 As mentioned above, although the correction method of the mechanism error of the articulated robot which concerns on one or several aspects of this invention was demonstrated based on embodiment, this invention is not limited to this embodiment. Without departing from the spirit of the present invention, various modifications as may occur to those skilled in the art may be applied to this embodiment, or a configuration constructed by combining components in different embodiments may be one or more of the present invention. It may be included within the scope of the embodiments.
　本発明の多関節ロボットの機構誤差の補正方法は、産業用の多関節ロボットの機構誤差の補正方法として有用である。 The method of correcting mechanical errors of an articulated robot according to the present invention is useful as a method of correcting mechanical errors of an industrial articulated robot.
　　１ａ，１ｂ，１ｃ，１１，１０１　　関節
　　２，１２　　手先
　　３，１３　　リンク
　　４，１０４，１０５　　アーム
　　５，１４　　モータ
　　６，１５　　エンコーダ
　　７　　平面治具
　　８，１６　　平面接触部
　　９　　球面治具
　１０　　球面接触部
　１７　　寸法
　２１　　基台
　３１，３２，３３，１００　　多関節ロボット
　４０　　制御部
　４１　　取得部
　４２　　補正部
　５１，６１，７１　　第一の位置
　５２，６２，７２　　第二の位置
　５３，６３，７３　　第三の位置
　５４，６４，７４　　第四の位置
１０２　　固定部
１０３　　手先
１１０　　部材
１１１　　先端
１１２　　プレート
１１３　　穴
１１４　　距離 1a, 1b, 1c, 11, 101 joints 2, 12 hands 3, 13 links 4, 104, 105 arms 5, 14 motors 6, 15 encoders 7 plane jigs 8, 16 plane contact portions 9 spherical jigs 10 spherical contact portions 17 Dimensions 21 Base 31, 32, 33, 100 Articulated Robot 40 Control Unit 41 Acquisition Unit 42 Correction Unit 51, 61, 71 First Position 52, 62, 72 Second Position 53, 63, 73 Third Position 54, 64, 74 Fourth position 102 Fixing part 103 Hand 110 Member 111 Tip 112 Plate 113 Hole 114 Distance

Claims (6)

  1. 　６自由度を有する多関節ロボットの機構誤差を補正する多関節ロボットの機構誤差の補正方法であって、
    　平面治具又は球面治具の表面の少なくとも４箇所の異なる位置それぞれにおいて、前記多関節ロボットの手先を拘束した状態で前記多関節ロボットの関節の角度を取得する取得工程と、
    　前記取得工程において取得された前記多関節ロボットの関節の角度を用いて、前記多関節ロボットの機構誤差を算出して補正する補正工程と、を有する、
    　多関節ロボットの機構誤差の補正方法。     A method of correcting a mechanical error of an articulated robot for correcting mechanical errors of an articulated robot having six degrees of freedom, comprising:
    An acquiring step of acquiring an angle of a joint of the articulated robot in a state in which the hand of the articulated robot is restrained at each of at least four different positions on the surface of a planar jig or a spherical jig;
    And correcting the mechanical error of the articulated robot using the angles of the joints of the articulated robot acquired in the acquiring step.
    Correction method of mechanical error of articulated robot.
  2. 　前記取得工程は、前記平面治具又は前記球面治具の表面の少なくとも４箇所の異なる位置それぞれにおいて、前記手先の姿勢が前記平面治具又は前記球面治具の表面の法線と同じになるように前記手先を拘束した状態で、前記多関節ロボットの関節の角度を取得する、
    　請求項１に記載の多関節ロボットの機構誤差の補正方法。     In the acquisition step, the posture of the hand is the same as the normal to the surface of the flat jig or the spherical jig at each of at least four different positions on the surface of the flat jig or the spherical jig. Acquiring the angle of the joint of the articulated robot while the hand is restrained at the
    A method of correcting a mechanical error of an articulated robot according to claim 1.
  3. 　前記多関節ロボットが、パラレルリンクロボットである、
    請求項１又は２に記載の多関節ロボットの機構誤差の補正方法。     The articulated robot is a parallel link robot,
    The correction method of the mechanism error of the articulated robot according to claim 1 or 2.
  4. 　前記取得工程は、前記治具の表面の少なくとも４箇所の異なる位置それぞれを通るように、前記平面治具又は前記球面治具の表面に接触させた状態の前記手先を移動させながら前記関節の角度を取得する、
    　請求項１から３のいずれか１項に記載の多関節ロボットの機構誤差の補正方法。     In the acquisition step, the angle of the joint is moved while moving the hand in a state of being in contact with the surface of the flat jig or the spherical jig so as to pass through at least four different positions on the surface of the jig. To get
    The correction method of the mechanism error of the articulated robot according to any one of claims 1 to 3.
  5. 　前記機構誤差は、前記多関節ロボットの手先と基台とを接続するリンクの長さの設計値と計測値との差である、
    　請求項１から４のいずれか１項に記載の多関節ロボットの機構誤差の補正方法。     The mechanical error is a difference between a design value and a measurement value of a length of a link connecting the hand of the articulated robot and the base.
    The correction method of the mechanism error of the articulated robot according to any one of claims 1 to 4.
  6. 　前記機構誤差は、前記手先の原点位置の設計値と計測値との差である、
    　請求項１から４のいずれか１項に記載の多関節ロボットの機構誤差の補正方法。     The mechanism error is a difference between a design value and a measurement value of the origin position of the hand.
    The correction method of the mechanism error of the articulated robot according to any one of claims 1 to 4.
PCT/JP2013/002665 2012-04-25 2013-04-19 Method for correcting mechanism error of articulated robot WO2013161242A1 (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104354166A (en) * 2014-07-28 2015-02-18 天津大学 Zero-point calibration method of three-degree-of-freedom parallel robot
CN106239510A (en) * 2016-08-25 2016-12-21 芜湖瑞思机器人有限公司 A kind of 3-dof parallel robot Zero calibration method
US11221642B2 (en) * 2017-05-19 2022-01-11 Kawasaki Jukogyo Kabushiki Kaisha Manipulating device

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6823795B2 (en) * 2015-12-01 2021-02-03 パナソニックＩｐマネジメント株式会社 Work equipment and teaching methods in work equipment
CN107351078A (en) * 2017-06-20 2017-11-17 天津市青创空间科技企业孵化器有限公司 A kind of robotically-driven executing agency
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KR102671823B1 (en) 2022-05-02 2024-06-03 한국전자기술연구원 Apparatus and method for calibration of articulated robot using constraint condition of end effector
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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58160086A (en) * 1982-03-19 1983-09-22 富士通株式会社 Method of determining coordinate of robot arm
JPS5958504A (en) * 1982-09-28 1984-04-04 Matsushita Electric Ind Co Ltd Origin offset adjusting method for arthrosis type robot
JPS5959394A (en) * 1982-09-29 1984-04-05 株式会社日立製作所 Device for estimating error of robot mechanism
JPS6228809A (en) * 1985-07-31 1987-02-06 Fujitsu Ltd Calibrating method for robot coordinate system
JPS6228808A (en) * 1985-07-31 1987-02-06 Fujitsu Ltd Calibrating method for robot coordinate system
JP2000097306A (en) * 1998-09-24 2000-04-04 Olympus Optical Co Ltd Parallel link mechanism

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06143166A (en) * 1992-11-06 1994-05-24 Meidensha Corp Method for correcting displacement in position of articulated robot
JP3443030B2 (en) * 1999-03-31 2003-09-02 オークマ株式会社 measuring device
JP4275632B2 (en) * 2005-03-01 2009-06-10 新日本工機株式会社 Calibration method for parallel mechanism mechanism, calibration verification method, calibration verification program, data collection method, and correction data collection method for spatial position correction
JP4638327B2 (en) * 2005-10-17 2011-02-23 新日本工機株式会社 Parallel mechanism device, parallel mechanism device calibration method, calibration program, and recording medium

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58160086A (en) * 1982-03-19 1983-09-22 富士通株式会社 Method of determining coordinate of robot arm
JPS5958504A (en) * 1982-09-28 1984-04-04 Matsushita Electric Ind Co Ltd Origin offset adjusting method for arthrosis type robot
JPS5959394A (en) * 1982-09-29 1984-04-05 株式会社日立製作所 Device for estimating error of robot mechanism
JPS6228809A (en) * 1985-07-31 1987-02-06 Fujitsu Ltd Calibrating method for robot coordinate system
JPS6228808A (en) * 1985-07-31 1987-02-06 Fujitsu Ltd Calibrating method for robot coordinate system
JP2000097306A (en) * 1998-09-24 2000-04-04 Olympus Optical Co Ltd Parallel link mechanism

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104354166A (en) * 2014-07-28 2015-02-18 天津大学 Zero-point calibration method of three-degree-of-freedom parallel robot
CN104354166B (en) * 2014-07-28 2016-05-04 天津大学 A kind of Zero calibration method of 3-dof parallel robot
CN106239510A (en) * 2016-08-25 2016-12-21 芜湖瑞思机器人有限公司 A kind of 3-dof parallel robot Zero calibration method
US11221642B2 (en) * 2017-05-19 2022-01-11 Kawasaki Jukogyo Kabushiki Kaisha Manipulating device

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