JP2015003361A - Compliance device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide compliance in a plane inward direction to be capable of performing a detailed power control of a movable part.SOLUTION: A compliance device comprises: a first plate 11 and a second plate 12 which are arranged opposing each other; three link mechanisms 13 which relatively displace the first plate 11 and the second plate 12 within the opposing surfaces; and a controller 14 which respectively controls the operation of the link mechanisms 13. The link mechanism 13 comprises: a first frame 131 and a second frame 132; a first rolling mechanism 133 which rotatably connects the first frame 131 with the first plate 11; a second rolling mechanism 134 which rotatably connects the second frame 132 with the second plate 12; a linear-movement mechanism 135 which relatively and displaceably connect the first frame 131 with the second frame 132; an angle sensor 136 which detects a rotation angle of the first rolling mechanism 133; and a rotary motor 137 which controls generation torque of the first rolling mechanism 133. The controller 14 controls the rotary motor 137 on the basis of the detection result by the angle sensor 136.

Description

  The present invention relates to a compliance device that absorbs positional errors between a robot and an assembly target component in an automatic assembly facility.

Conventionally, in production equipment, when an automatic machine such as a robot (hereinafter referred to as a robot) is used to perform component supply, assembly, component mounting process, etc., position error (target component dimensional error, robot positioning error, etc.) ) May be attached between the robot and the hand or on the jig for the purpose of absorbing the). In this compliance apparatus, an apparatus (active compliance apparatus) that can freely change the magnitude of compliance depending on the type of work is known (see, for example, Patent Document 1).
In addition, there is an operation that requires a multi-degree-of-freedom compliance device having compliance in a plurality of directions. In response to this requirement, an active compliance device with 6 degrees of freedom is known (see, for example, Patent Document 2).

JP 2009-271883 A JP 2012-61564 A

  Here, the direction in which compliance is required differs depending on the contents of the process. For example, in a process using a SCARA (horizontal type) robot, compliance in the in-plane (XYθ) direction may be effective. On the other hand, the apparatus disclosed in Patent Document 1 has a problem that the degree of freedom is insufficient. In the device disclosed in Patent Document 2, actuators and sensors are arranged on the movable part of the link, and the reaction force generated by these cables is not constant depending on the position and posture of the link. It becomes a factor that hinders the fine force control.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an active compliance device having compliance in the in-plane direction and capable of fine force control of a movable portion. .

  The compliance device according to the present invention includes three first and second plates arranged opposite to each other, and three plates arranged between the first and second plates to relatively displace the first and second plates in the opposed surface. The link mechanism and a control unit that controls the operation of each link mechanism are provided, and the link mechanism is connected to the first and second frames and a first plate that rotatably connects the first frame to the first plate. A rotation mechanism, a second rotation mechanism that rotatably connects the second frame to the second plate, a linear motion mechanism that connects the first and second frames so as to be relatively displaceable, An angle sensor that detects the rotation angle of the first rotation mechanism and a rotation motor that controls the torque generated by the first rotation mechanism, and the control unit controls the rotation motor based on the detection result of the angle sensor. It is.

  According to the present invention, since it is configured as described above, it is possible to obtain an active compliance device having compliance in the in-plane direction and capable of fine force control of the movable portion.

It is a perspective view which shows the structure of the compliance apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the structure of the control part in Embodiment 1 of this invention. It is a figure which shows arrangement | positioning of the 1st, 2nd rotation mechanism of the compliance apparatus which concerns on Embodiment 1 of this invention, and the 1st-3rd link mechanism. It is a figure which shows the example of the relationship between the displacement with respect to the 1st plate of the 2nd plate to which the compliance apparatus which concerns on Embodiment 1 of this invention is applied, and the torque which generate | occur | produces with a rotary motor. It is a flowchart which shows the control action by the control part in Embodiment 1 of this invention. It is a perspective view which shows the case where the compliance apparatus which concerns on Embodiment 1 of this invention is attached between the robot and the hand. It is a perspective view which shows the case where the compliance apparatus which concerns on Embodiment 1 of this invention is attached to a jig | tool. It is a perspective view explaining the example of a work for showing the example of operation of the compliance apparatus concerning Embodiment 1 of this invention. It is a perspective view which shows the state which attached the compliance apparatus to the jig | tool of FIG. It is a perspective view which shows the operation | movement in the example of operation of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a perspective view showing a configuration of a compliance device 1 according to Embodiment 1 of the present invention.
The compliance device 1 is a device having compliance with respect to a position (XY) direction and a posture (θ) direction in a plane. That is, it is a device having compliance with three degrees of freedom of XYθ. As shown in FIG. 1, the compliance device 1 includes first and second plates 11 and 12 that are disposed to face each other, and first to third link mechanisms 13 a to 13 c that are disposed between the first and second plates. The control unit 14 controls the operation of the first to third link mechanisms 13a to 13c.

  The first to third link mechanisms 13a to 13c are for displacing the first and second plates 11 and 12 relatively in the XYθ directions within the opposing surfaces (in the plane). In the following description, the first to third link mechanisms 13a to 13c are referred to as a link mechanism 13 unless it is particularly necessary to distinguish them.

  The link mechanism 13 is provided with first and second frames 131 and 132. One end of the first frame 131 is provided with a first rotation mechanism 133 for rotatably connecting the first frame 131 to the first plate 11. Similarly, the second frame 132 is provided with a second rotating mechanism 134 for rotatably connecting the second frame 132 to the second plate 12. Further, a linear motion mechanism 135 that connects the first and second frames 131 and 132 so as to be relatively displaceable is provided between the first and second frames 131 and 132. With this linear motion mechanism 135, the distance between the first and second rotation mechanisms 133, 134 can be made variable, and the length of the link mechanism 13 can be extended and retracted.

  In addition, an angle sensor 136 that detects the rotation angle of the first rotation mechanism 133 and a rotation motor 137 that controls the torque generated by the first rotation mechanism 133 are connected to the first rotation mechanism 133. By the rotation control by the rotation motor 137, each link mechanism 13 can perform a swinging operation relative to the first plate 11.

  The control unit 14 controls the rotation motor 137 based on the rotation angle of the first rotation mechanism 133 detected by the angle sensor 136. As shown in FIG. 2, the control unit 14 includes a compliance value setting unit 141, a sensor value acquisition unit 142, an angle calculation unit 143, a motor torque calculation unit 144, a motor torque output unit 145, and a compliance value change determination unit 146. Has been.

  The compliance value setting unit 141 sets a compliance value in the XYθ direction that occurs in the second plate 12. In addition, when the compliance value change determination unit 146 determines that the compliance value needs to be changed, the compliance value is changed. For example, the compliance is changed when a command from the host controller is given when the work process is changed.

  The sensor value acquisition unit 142 acquires a sensor value indicating a detection result by the angle sensor 136.

  The angle calculation unit 143 calculates the rotation angle of the first rotation mechanism 133 based on the sensor value of the angle sensor 136 acquired by the sensor value acquisition unit 142.

  The motor torque calculation unit 144 calculates the torque required for the rotary motor 137 based on the rotation angle of the first rotation mechanism 133 calculated by the angle calculation unit 143.

  The motor torque output unit 145 outputs the torque calculated by the motor torque calculation unit 144 to the rotary motor 137.

  The compliance value change determination unit 146 determines the compliance set by the compliance value setting unit 141 when, for example, the host controller determines to change the compliance setting according to the type of work in the automatic assembly facility to which the compliance device 1 is applied. This determines whether or not the value needs to be changed.

  Then, the relative displacement generated in the XYθ direction by the first and second plates 11 and 12 due to the external force appears as an angle change of the first rotating mechanism 133. Therefore, the angle is detected by the angle sensor 136 and the control unit 14 The rotational torque is calculated using the detection result and the preset compliance value, and the rotational motor 137 generates the rotational torque. Thereby, the compliance apparatus 1 can be used as an active compliance apparatus having free compliance in each of the in-plane (XYθ) directions.

Next, calculation of torque generated by the rotary motor 137 of the compliance device 1 configured as described above will be described.
First, as shown in FIG. 3, the compliance device 1 of the present invention includes three rotation mechanism connecting portions (B _{1 to} B ₃ ) on the first plate 11 and three portions on the second plate 12. rotation mechanism connecting portion and _(E 1 _{~E 3),} linked via a first and second rotation mechanisms 133 and 134 in the first to third link mechanism 13 a to 13 c (length _L 1 ~L ₃₎ configuration And

Further, as a coordinate system, set the coordinate system .SIGMA.X _B -Y _B on the first plate 11, the coordinate system? X _e -y _e on the second plate 12. Coordinate system? X _e -y _e is a coordinate system that changes the relative position and angle with respect to the coordinate system .SIGMA.X _B -Y _B.

At this time, the position of the second rotation mechanism 134 expressed by the coordinate system ΣX _B -Y _B is expressed by the following equation (8).

In particular,

とする。つまり、

とする。 Next, each element of the matrix J is obtained. In equation (10)

And That means

And

At this time, each element of the matrix J can be calculated as in the following equation (14).

が得られる。そして、式（１８）を変形すると、

が得られる。つまり、下式（２０）が成立する。

Here, from the principle of virtual work, [virtual work by the actuator mounted on the first rotating mechanism 133 = virtual work of the second plate 12] is established.

Is obtained. And when transforming equation (18),

Is obtained. That is, the following formula (20) is established.

となる。この式（２１）を（２０）に代入すると

が得られる。

It becomes. Substituting this equation (21) into (20)

Is obtained.

Next, the case where the compliance apparatus 1 of the present invention is used as a device that generates arbitrary compliance characteristics (when used as active compliance) will be described.

Substituting this equation (23) into equation (22)

Next, FIG. 4 shows an example of calculation regarding the relationship between the displacement of the second plate 12 with respect to the first plate 11 to which the compliance device 1 of the present invention is applied and the torque generated by the rotary motor 137.
The position of each rotating _{mechanism, Bx 1 = 21.2mm, By 1} = 21.2mm, Bx 2 = -29.0mm, By 2 = 7.8mm, Bx 3 = 7.8mm, By 3 = -29.0mm were _{ex 1 = -21.2mm, ey 1 =} 21.2mm, ex 2 = -7.8mm, ey 2 = -29.0mm, ex 3 = 29.0mm, and ey 3 = 7.8 mm.
Further, in the following calculation example, the compliance device 1 moves as a soft spring in the Y direction and moves as a hard spring in the X and θ directions as KX = 10 N / mm, KY = 0.1 N / mm, Kθ = 10 N / rad, and inertia and viscosity were omitted.

  For example, starting from the position of the origin position (X, Y, θ) = (0, 0, 0), it is moved by external force to (X, Y, θ) = (0.1 mm, 5.0 mm, 0.1 deg) When this is done, the torque of each rotary motor 137 may be generated as shown in FIG.

Next, the control operation by the control unit 14 of the compliance device 1 configured as described above will be described with reference to FIG.
In the control operation by the control unit 14, as shown in FIG. 5, first, the compliance value setting unit 141 sets the compliance value of each link mechanism 13 (step ST61).

  Next, the sensor value acquisition unit 142 acquires a sensor value indicating a detection result by the angle sensor 136 (step ST62).

  Next, the angle calculation unit 143 calculates the rotation angle of the first rotation mechanism 133 from the sensor value of the angle sensor 136 (step ST63).

  Next, the motor torque output unit 145 outputs the torque calculated by the motor torque calculation unit 144 to the rotary motor 137 (step ST65).

  Next, the compliance value change determination unit 146 determines whether it is necessary to change the compliance value set by the compliance value setting unit 141 according to a command from the host controller, for example (step ST66). In this step ST66, when the compliance value change determination unit 146 determines that the compliance value needs to be changed, the sequence returns to step ST61, and a new compliance value is set. On the other hand, when the compliance value change determination unit 146 determines in step ST66 that the compliance value does not need to be changed, the sequence returns to step ST62.

Next, an application example of the compliance device 1 configured as described above will be described with reference to FIGS.
FIG. 6 is a perspective view showing a case where the compliance device 1 according to the first embodiment of the present invention is attached between the robot 51 and the hand 52.
As shown in FIG. 6, by using the compliance device 1 shown in FIG. 1 between the robot 51 and the hand 52 in the automatic assembly facility, the assembly target component 54 housed in the robot 51 and the pallet 53 can be obtained. Thus, it is possible to avoid an excessive force from being applied to the hand 52 and the component 54. At that time, the compliance value can be set and changed freely (active compliance device), so that the spring constant setting value is increased for various parts and operations (parts that are tightly fitted, and parts that are easily damaged) To reduce the setting value). Further, by making it possible to independently change the compliance value in the XYθ direction, it is possible to cope with work from a plurality of directions (when a plurality of parts are assembled and the abutting direction is different). In the present invention, the motor and the sensor are arranged so as not to move relative to the first plate 11, so that the influence of the reaction force of those cables is not given to the second plate 12. For this reason, it is possible to perform a work on a component that is easily damaged with a finer force than before.

FIG. 7 is a perspective view showing a case where the compliance device 1 according to Embodiment 1 of the present invention is attached to the jig 55.
As shown in FIG. 7, by installing the compliance device 1 shown in FIG. 1 on a jig 55 for assembling parts, a position error between the robot 51 and the part 54 to be assembled is absorbed, and an excessive force is applied to the hand 52. And it can avoid adding to the component 54. FIG. At this time, by making it possible to independently change the compliance value in the XYθ direction in the plane, it is possible to cope with various parts 54 and work. For example, when the part 54b gripped by the hand 52 of the robot 51 is inserted into the part 54a fixed to the jig 55, the parts are centered by the hand 52 in the X direction and the θ direction, so that high positional accuracy is obtained. However, the position may be shifted in the Y direction. In that case, by setting only the Y direction softly, the hand 52 and the parts 54a and 54b are not precisely aligned due to position errors (dimensional errors of the parts 54a and 54b, positioning errors of the robot 51), etc. Even if it exists, the position error can be absorbed by the compliance apparatus 1 of the present invention. At this time, in the present invention, as described above, it is possible to perform a work of a component that is easily damaged with a finer force than before.

Next, an operation example of the compliance device 1 according to the first embodiment of the present invention will be described with reference to FIGS.
The configuration in which the compliance setting can be individually set / changed in each direction as in the compliance device 1 of the present invention is effective in the following case work.

In the operation shown in FIG. 8, the parts 54d and 54e are used on the surface 541 and the surface 542, respectively, with respect to the parts 54c that are easily damaged and mounted on the workpiece 56 firmly clamped on the jig 55a. To be mounted. It is assumed that the component 54d needs to be positioned (precise) in the Y direction, and the component 54e needs to be positioned (precise) in the X direction.
In such an operation, since the workpiece 56 is fixed to the jig 55, the dimensional variation of the components 54c to 54e, the variation of the mounting position of the component 54c, the variation of the clamping position of the workpiece 56 by the jig 55a, the robot Due to the positioning error 51, an excessive load may be applied to the component 54c when mounting the components 54d and 54e.

When the compliance device 1 of the present invention is mounted on the lower part of the jig 55a, it becomes as shown in FIG.
Then, as shown in FIG. 10A, when the component 54d is mounted by this compliance device 1, the spring constant settings in the X direction and the θ direction are reduced, and the spring constant settings in the Y direction are extremely increased. As a result, the component 54d can be abutted and mounted without placing an excessive load on the component 54c in the positioning state in the Y direction and in the X direction and the θ direction.

Next, as shown in FIG. 10B, when the component 54e is mounted by this compliance device 1, the spring constant settings in the Y direction and the θ direction are made small, and the spring constant settings in the X direction are made very large. Thus, the component 54e can be abutted and mounted without placing an excessive load on the component 54c in the positioning state in the X direction and in the Y direction and the θ direction.
In this way, different processes can be mounted using the same jig 55a.

  As described above, according to the first embodiment, the first and second plates 11 and 12 disposed opposite to each other and the first and second plates 11 and 12 are disposed between the first and second plates 11 and 12. 11 and 12 are provided with three link mechanisms 13 for relatively displacing the opposing surfaces within the opposing surface, and a control unit 14 for controlling the operation of each link mechanism 13, and the link mechanism 13 includes first and second frames 131 and 132. A first rotation mechanism 133 that rotatably connects the first frame 131 to the first plate 11, and a second frame 132 that pivotally connects to the second plate 12. A second rotation mechanism 134; a linear motion mechanism 135 that connects the first and second frames 131 and 132 so as to be relatively displaceable; an angle sensor 136 that detects a rotation angle of the first rotation mechanism 133; 1 Rotation mechanism 133 And the control unit 14 is configured to control the rotation motor 137 based on the detection result of the angle sensor 136. Therefore, the control unit 14 has compliance in the in-plane direction, and the movable portion is fine. It is possible to obtain an active compliance device that can perform force control.

  In the present invention, any constituent element of the embodiment can be modified or any constituent element of the embodiment can be omitted within the scope of the invention.

DESCRIPTION OF SYMBOLS 1 Compliance apparatus 11, 12 1st, 2nd plate 13, 13a-13c 1st-3rd link mechanism 14 Control part 51 Robot 52 Hand 53 Palette 54, 54a-54e Parts 55, 55a Jig 56 Work 131, 132 1st 1 and 2 frames 133 and 134 1st and 2nd rotation mechanism 135 linear motion mechanism 136 angle sensor 137 rotation motor 141 compliance value setting unit 142 sensor value acquisition unit 143 angle calculation unit 144 motor torque calculation unit 145 motor torque output unit 146 Compliance value change determination sections 541 and 542

Claims (2)

First and second plates opposed to each other;
Three link mechanisms arranged between the first and second plates and relatively displacing the first and second plates within the opposing surface;
A control unit for controlling the operation of each link mechanism,
The link mechanism is
First and second frames;
A first rotation mechanism that rotatably connects the first frame to the first plate;
A second rotation mechanism for rotatably connecting the second frame to the second plate;
A linear motion mechanism for connecting the first and second frames so as to be relatively displaceable;
An angle sensor for detecting a rotation angle of the first rotation mechanism;
A rotation motor for controlling the torque generated by the first rotation mechanism,
The said control part controls the said rotary motor based on the detection result by the said angle sensor. The compliance apparatus characterized by the above-mentioned. The controller is
A compliance value setting unit for setting a compliance value generated in the second plate;
An angle acquisition unit for acquiring a sensor value indicating a detection result by the angle sensor;
An angle calculation unit that calculates a rotation angle of the first rotation mechanism based on the sensor value acquired by the angle acquisition unit;
A motor torque calculator that calculates a torque required for the rotary motor based on the rotation angle of the first rotating mechanism calculated by the angle calculator;
The compliance device according to claim 1, further comprising: a motor torque output unit that outputs the torque calculated by the motor torque calculation unit to the rotary motor.

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