JPH09155776A - Robot controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a cycle time by finding acceleration in accordance with a load marginal value computed from a stored maximum allowable load current in a motor and a load current in the motor when a robot is operated, to control the movement of the robot. SOLUTION: A six-axis multiarticulated robot has encoders E1-E6 to detect the rotating angles of six-axis driving servo motors 21-26 and current detectors 61-66 to detect a current value Ii, these output signals being input to a host CPU 400. Load currents in the respective motors are detected from the outputs of the current detectors 61-66 and the maximum load current flowing when the robot is operated at a fixed acceleration is stored in a memory means. The ratio of the stored maximum allowable load current to the maximum load current is computed, an acceleration to determine a moving speed in accordance with the computed load margin ratio is computed and the moving speed is determined to control the movement of the robot in a accordance with an interpolation point.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixed acceleration value and a speed during deceleration based on a fixed acceleration value and a fixed speed value that are permissible for a motor to drive the robot when a maximum load acts on the robot. The present invention relates to a robot control device capable of high-speed positioning in a robot whose pattern is determined.

[0002]

2. Description of the Related Art In a conventional robot controller, the load current of all-axis motors does not exceed the maximum allowable load current regardless of whether or not the work is transported and the weight of the work (see FIG. 15).
A fixed acceleration value and a fixed speed value are set so as to always control the moving operation of the robot by determining the speed pattern (see FIG. 14) based on the fixed acceleration value and the fixed speed value. .

[0003]

Since the conventional robot control device always determines the speed pattern based on the fixed acceleration value and speed value as described above, when the work is not transported or when the light work is not performed. Even when carrying the robot, the motor current is controlled based on the same fixed acceleration value and fixed speed value as at the time of maximum load, and the movement operation of the robot is controlled. Therefore, the capacity of the motor is not effectively used. Therefore, there is a problem that the cycle time becomes long.

Therefore, the present inventors have noticed that the robot can be moved quickly when the load current of the all-axis motor does not reach the maximum load current, and the maximum allowable load current of the motor and the robot are operated. The load margin value is calculated from the ratio of the maximum load current based on the fixed acceleration at this time, the acceleration is calculated based on the calculated load margin value, and the motor is controlled by the control characteristic according to the calculated acceleration. As a result of further research and development focused on the technical idea of the present invention, the present invention has been achieved which achieves the purpose of effectively using the motor capacity and shortening the cycle time.

[0005]

A robot control apparatus according to the present invention (a first invention according to claim 1) is a robot for positioning a robot hand at a teaching point given according to an operation trajectory, and has a maximum load. A robot control device comprising a control means for controlling a movement operation of the robot by determining a movement speed based on a fixed acceleration allowable by the motor for driving the robot when the robot is actuated. Load current detection means for detecting the load current of the motor, maximum allowable load current storage means for storing the maximum allowable load current of the motor, and the robot operates at the maximum allowable load current of the motor and the fixed acceleration. Load margin value calculating means for calculating a load margin value from the maximum load current at the time, and based on the calculated load margin value and the fixed acceleration In which and a acceleration calculating means for calculating an acceleration to determine the moving speed.

A robot controller according to the present invention (a second invention according to claim 2) is a robot for positioning a robot hand at a teaching point given according to a motion locus, when a maximum load acts on the robot. Fixed acceleration storage means for storing a fixed acceleration allowable for driving the robot by a plurality of motors provided on each axis, and movement of the robot by determining a moving speed based on the stored fixed acceleration. In a controller of a robot having a control means for controlling an operation, a load current detecting means for detecting load currents of the plurality of motors for driving the robot, and a maximum allowance for storing a maximum allowable load current of the motors. A load current storage means and a maximum load memory for storing the maximum load current detected by the load current detection means when the robot operates at the fixed acceleration. Load current storage means, load margin ratio calculation means for calculating a load margin ratio from the ratio of the maximum allowable load current of the motor and the maximum load current, and the plurality of motors based on the calculated load margin ratio. And an acceleration calculating means for calculating an acceleration that determines a moving speed for driving.

A robot controller according to the present invention (the third invention according to claim 3) is the robot according to the second invention, wherein the maximum load current storage means is an acceleration state of the robot, a constant speed state,
The maximum load current in the decelerated state is stored.

(Operation) In the robot controller according to the first aspect of the present invention, the load current detecting means detects the load current of the motor driving the robot, and the load margin value calculating means makes the maximum. A load margin value is calculated from the maximum allowable load current of the motor stored in the allowable load current storage means and the maximum load current when the robot operates at the fixed acceleration, and the acceleration calculation means calculates the load margin value. An acceleration for determining the moving speed is calculated based on a margin value and the fixed acceleration, and the moving speed is determined based on the calculated acceleration to control the moving operation of the robot.

In the robot controller according to the second aspect of the present invention, the load current detecting means detects the load currents of the plurality of motors for driving the robot, and the maximum load current storing means detects the fixed acceleration. And stores the maximum load current detected by the load current detection means when the robot operates, and the load margin ratio calculation means stores the maximum allowable load current of the motor stored in the maximum allowable load current storage means. The ratio of the maximum load current is calculated, the acceleration calculation means calculates an acceleration that determines the moving speed for driving the plurality of motors based on the calculated load margin ratio, and the calculated acceleration is calculated. The moving speed is determined on the basis of the moving speed, and the moving operation of the robot is controlled based on the next interpolation point obtained by the moving speed.

In the robot controller according to the third aspect of the present invention having the above-described structure, in addition to the operation of the second aspect, the maximum load current storage means causes the maximum load current in the acceleration state, constant speed state, and deceleration state of the robot. The load margin ratio calculating means calculates the load margin ratio in each state based on the maximum load current.

[0011]

The robot controller according to the first aspect of the present invention, which has the above-described operation, calculates from the maximum allowable load current of the motor stored in the maximum allowable load current storage means and the load current of the motor when the robot operates. The acceleration is obtained based on the load margin value determined, and the movement speed is determined based on this acceleration to control the movement operation of the robot. Therefore, it is possible to effectively use the capacity of the motor and shorten the cycle time. Play.

The robot controller according to the second aspect of the present invention, which has the above-described operation, has the maximum allowable load current of the motor stored in the maximum allowable load current storage means and the maximum load of the plurality of motors when the robot operates. Since the acceleration for determining the moving speed for driving the plurality of motors based on the load margin ratio calculated from the current is obtained, and the moving speed of the robot is controlled by determining the moving speed based on the obtained acceleration, There is an effect that the ability of the motor is more effectively used and the cycle time is effectively shortened.

In addition to the effect of the second aspect of the invention, in the robot controller according to the third aspect of the present invention, the maximum load current storage means causes the maximum load current in the acceleration state, constant speed state, and deceleration state of the robot. Since the load margin ratio is calculated on the basis of the maximum load current, it is possible to perform control according to each of the acceleration state, the constant speed state, and the deceleration state of the robot.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) The first embodiment of the present invention will be described below. FIG. 1 is a diagram showing a configuration of a 6-axis articulated robot. Reference numeral 1 denotes a robot, a base 11 for fixing the robot 1 to a floor, a column 12 fixedly mounted on the base 11, a body 13 rotatably arranged on the column 12 around an a-axis, An upper arm 14 rotatably supported on the body 13 about the b-axis.
A forearm 15 rotatably supported on the upper arm 14 about the c-axis, and the forearm 15
At the tip end of the twist list 16 rotatably supported around the d-axis, the twist list 16 is rotatably supported around the e-axis, and the bend list 17 is provided at the tip of the bend list 17. a swivel wrist 18 having a flange 181 rotatably supported about the f-axis,
And a hand 19 attached to the flange 181.

FIG. 2 is a block diagram showing the configuration of the robot controller according to the first embodiment. In FIG. 2, servomotors 21 to 26 are a to f in FIG.
Drive 6 axes. The respective rotation angles of the servomotors 21 to 26 are detected by the encoders E1 to E6, and the servomotors 21 to 26 have current detectors 61 to 66 constituting the load current detecting means.
Is attached to detect the current value Ii (i = 1 to 6) of each servo motor 21 to 26, and the host CPU 400
And the host CPU 4 which is input to the servo driver 5
00 is used for the calculation of the moment of inertia and gravity torque of each axis, and the servo driver 5 for position feedback control, speed feedback control, and current feedback control.

As shown in FIG. 2, the control device 4 includes a host CPU 400, an operation start instruction, a jog operation instruction,
It comprises an operation panel 401 for instructing teaching points, a memory 402 in which programs and the like are stored in advance, and a tool drive circuit 403 for controlling the opening / closing operation of the hand 19.

The servo driver 5 is composed of servo CPUs 51 to 56 corresponding to the respective axes, and the respective axes i (i = 1 to 6) output from the host CPU 400.
The output torque output to the servomotors 21 to 26 is controlled based on the angle command values θ1 to θ6, the inertia moment Di, and the gravity torque Ti.

In the memory 402 of the control device 4, a PDA area for storing teaching point data representing the position and posture of the hand 19 and the teaching point data PD for the robot 1 are stored.
P in which a program for operating according to A is stored
Command value of area A and fixed speed V ₀ and fixed acceleration a ₀ , maximum allowable load current I ₀ , acceleration Am and deceleration An set so that the load current of all-axis motor does not exceed the maximum allowable load current And an SDA area that stores the target speed,
Maximum load current value I _{mi of the} servomotors 21 to 26
The ITA area storing (i = 1 to 6) and the angle command values θ1 to θ of each axis at the interpolation point obtained by the interpolation calculation
6 and an ANG area for storing the detected angles α1 to α6 output from the encoders E1 to E6.

The operation program stored in the PA area is for moving the tip of the hand 19 of the robot 1 as shown in FIG. 7 in accordance with the instruction shown in FIG. In FIG. 6, line number 1 is an instruction word for positioning the tip of the hand 19 at the machine origin ORG, and line number 2 is M for positioning at the teaching point P2 by linear interpolation.
It is an OVE command word, and line number 3 is a MOVE command word for positioning the teaching point P1 by linear interpolation. Line number 4
Is a command for closing the hand 19 and gripping an article, line number 5 is a MOVE command for positioning to teaching point P2 by linear interpolation, and line number 6 is positioning for teaching point P3 by linear interpolation. Line No. 7 is a MOVE command word that is used to position the teaching point P4 by linear interpolation.
It is a VE command word. The line number 8 is a command for opening the hand 19 and leaving the article, the line number 9 is a MOVE command for positioning at the teaching point P4 by linear interpolation, and the line number 10 is for the hand 19. Machine tip O at the tip
It is an instruction word for positioning to RG.

According to the operation program of FIG. 6, the robot stops at the teaching point P1 from the machine origin ORG via the teaching point P2 as shown in FIG. 7, and then closes the hand 19 to grip the object and teach the teaching point P2. , P3 via P3, open the hand 19 to leave the object, and move to the machine origin ORG via the teaching point P3.

The main program for decoding the operation program by the host CPU 400 is a flowchart as shown in FIG. In step 100, M
When the OVE command is decoded, in step 102, an interpolation calculation for moving the hand 19 from the current position to the designated teaching point is executed. Then, the angle command values θ1 to θ6 of the respective axes obtained by the interpolation calculation
Is output to the servo CPUs 51 to 56.

In step 104, HAND OF
When the F command is decoded, in step 106, the tool driving circuit 403 is instructed to close the hand 19, and the process returns to step 100.

In step 110, HAND ON
When the command is decoded, in step 112, the tool driving circuit 403 is instructed to open the hand 19, and the process returns to step 100.

Next, M for positioning by the linear interpolation
A detailed processing procedure of the OVE instruction will be described with reference to FIGS. The program of FIG. 4 starts the process from step 200 when the MOVE command word is given, and then repeats from step 208 at every interpolation cycle ΔT until the movement to the teaching point designated by the MOVE command word is completed. To be executed. When the movement to the teaching point designated by the MOVE command is completed, the process returns to the main block in FIG.

In step 200, the direction vector of the rotation axis is calculated from the position and orientation of the starting point and the position and orientation of the next positioning target point given as the teaching data expressed in the world coordinate system, and in step 202, A rotation angle Θ about the rotation axis is calculated.

Next, at step 204, it is judged if the moving speed V _m at that time is 0, that is, if it is in a stopped state. If it is in the stopped state, in step 206, the moving speed V _m on the operation locus is fixed to the fixed acceleration a based on the equation 1.
It is incremented by ₀ using ₀ .

(Equation 1)

In step 208, the interpolation distance ΔL from the section start teaching point on the motion locus is updated based on the equation 2.

(Equation 2) V _m · ΔT represents the moving distance on the motion locus in one interpolation cycle.

Next, in step 210, the MO
The remaining distance R on the motion locus with respect to the target position given by the VE command is calculated based on Equation 3.

(Equation 3) However, L is the section distance on the motion locus to be moved after the movement command.

In step 212, it is judged whether or not the interpolation distance ΔL is larger than the section distance L. If it is larger, the interpolation point exceeds the target position. Therefore, in step 214, the interpolation distance ΔL is set to the section distance L. Equal to.

Next, in step 215, the interpolation angle ΔΘ around the rotation axis is calculated based on the equation (4).

(Equation 4) That is, the ratio of the length of the interpolation point on the operation locus is made equal to the ratio of the angle around the rotation axis. In step 216, a posture conversion matrix R (4 × 4 homogeneous coordinate matrix) for converting the position and posture of the start point into the position and posture at the interpolation point using the interpolation angle ΔΘ and the interpolation ratio ΔL / L is obtained. Is calculated.

Next, in step 217, the attitude transformation matrix is applied to the homogeneous coordinate matrix representing the position and orientation of the starting point, and the homogeneous coordinate matrix representing the position and orientation at the interpolation point is calculated. In step 218, the homogeneous coordinate matrix of the position and orientation expressed in the world coordinate system at the interpolation point is converted into joint coordinates, and the value in the joint coordinate system, that is, the rotation angle θi (θ1 to θ6) of each axis.
Is calculated and this value is stored in the INA area of the memory 402.

In step 219, the rotation angle θ of each axis
i is output to the servo CPUs 51 to 56. As a result, each axis of the robot rotates to the target rotation angle during the interpolation cycle ΔT, and the tip of the hand 19 moves on the movement trajectory to the interpolation point at the moving speed V _m .

Next, at step 220, the current value I _{i of} the servo motors 21 to 26 provided on each axis is detected and is equal to the current value I _{j-1i of} the servo motors 21 to 26 previously detected at step 222. If it is not equal, then in step 224 I _ji
Be I _i .

If they are equal, in step 226, the maximum allowable load current I ₀ of the servo motor I ₀ is the load margin ratio a _i (= I ₀ / I _i) which is the ratio to the current value I _i of the servomotors 21 to 26 of each axis. ) Is calculated to obtain the minimum value a of the load margin ratio a _i (that is, I _i is maximum). With then performing the calculation of the fixed acceleration a ₀ to the load margin ratio a _i acceleration A _m based on the number 5 for multiplying the minimum value a of, and at the end the inertia I _s at the start of the maximum allowable load current I ₀ The deceleration A _n is calculated based on the equation 5 by multiplying the inertia I _e by

(Equation 5)

If not equal, in step 232,
The remaining distance R and the required stop distance (V _m ² / 2A _m ) are compared. The required stop distance is the distance required to decelerate at a deceleration commanded from the speed V _m at that time and stop at the target position. If the remaining distance R is equal to or greater than the stop distance, it is not necessary to decelerate yet, so the routine proceeds to step 236.

In step 232, the remaining distance R
Is smaller than the required stop distance, step 23 is performed to perform deceleration processing for positioning with respect to the target position.
In 4, the subtraction of the moving speed V _m is executed based on the equation 6.

(Equation 6)

In step 236, the magnitude relationship between the fixed speed V ₀ and the moving speed V _m is determined according to the _{equation (} 7).

(Equation 7)

Next, at step 236, when the moving speed V _m calculated based on the above equation 7 is smaller than the fixed speed V _0, at step 238 the moving speed V _m is determined by the following _equation 8.
Acceleration correction is performed based on.

(Equation 8)

Next, at step 240, the interpolation distance Δ
It is determined whether L is equal to the section distance L. If they are equal, the process proceeds to the next step 242, which means that the interpolation point has reached the target teaching point, and the interpolation cycle ΔT, that is, the next control time is awaited. Therefore, in this case, the velocity control according to this MOVE command is ended while the corrected movement velocity V _m is held, and the process returns to the main program shown in FIG. If the next command is MOVE again, speed control by the moving speed V _m is executed.

In step 240, the interpolation distance Δ
When L is not equal to the section distance, the execution of this MOVE command is completed.

The controller of the robot of the first embodiment is
Through the above processing, the maximum allowable load current I ₀ of the servo motor and the current values I _i of the servo motors 21 to 26 for each axis are set.
The ratio of which calculates the load margin ratio a _i and a _i minimum value a
And a fixed acceleration a ₀ is multiplied by the minimum value a of the load margin ratio to obtain an acceleration A _m and a deceleration A _n.
Is calculated and the moving speed V _m is calculated based on the calculated accelerations A _m and A _n , and the moving speed V _m is controlled in real time by the calculated moving speed V _m . Looking at the current value applied to, the applied current value can be brought close to the maximum allowable load current I ₀ , as shown by the solid lines in FIGS. 8 and 9, and the capacity of the servomotor 2 can be made effective. It has the effect of using it and shortening the cycle time. The solid line 0 to t ₁ in FIG. 9 overlaps the dotted line because it is controlled by the fixed acceleration a ₀ when the movement control starts.

Further, the robot controller of the first embodiment makes the operating speed variable according to the load current of the servo motor for each axis of the robot. For example, the robot hand 19 grips the same operating locus. The movement speed can be changed according to the weight of the work, and the acceleration and speed for driving the servo motor of each axis are determined based on the load margin ratio as described above, so the operation locus changes. Never. In addition, the cycle time can be shortened even when the robot does not repeat.

Further, since the control device for the robot of the first embodiment uses the current value detected by the current feedback originally provided in the robot, it is necessary to provide the load detecting means separately provided. In addition, there is an effect that speed control according to a load is possible with a simple configuration.

(Second Embodiment) The robot control device of the second embodiment monitors the switching of the type of the work held by the robot, in comparison with the device of the first embodiment which controls in real time, and when the switched is acceleration zone a ₀ as shown in FIG. 14 for example when the robot moves between two points, deceleration section -a _0, to not each of the servo motors 21 in one cycle consisting of constant speed section a _c 26 is added with a function of monitoring the change in the current value of 26 and calculating the optimum acceleration and speed of each section based on the monitored current value. Only the difference will be described with reference to FIGS. 10 to 12. .

The main program for deciphering the operation program by the host CPU 400 is the flowchart shown in FIG. 3 similar to the first embodiment, but when it is judged to be the MOVE instruction in step 100 of FIG. Go to step 102. The details of this step 102 are performed according to the flowchart shown in FIG.

If it is determined in step 300 that the work has been switched by determining the instruction in the program or the operation panel 401, in step 302, the movement control by the MOVE command for one cycle is first performed, and at the same time, in step 304. The current value I _{i of} each servomotor 21-26 is monitored.

The movement control in step 302 is as follows.
Since it is the same as steps 200 to 219 of the flowchart of the first embodiment shown in FIG. 4, description thereof will be omitted.

The current monitor in step 304 captures the current during acceleration / deceleration and constant speed for each movement command, which will be described in detail below with reference to FIG. In step 402, it is compared whether or not the previous moving speed V _{j m-1} on the motion locus and the current moving speed V _jm are equal.

Previous moving speed V _{j-1 m} and present moving speed V
_{If jm} is not equal, it is determined to be an acceleration state or a deceleration state, and it is determined in step 404 whether the current moving speed V _jm is higher than the previous moving speed V _{j-1 m.} The value I _i is detected, and if smaller, the current value I _i is detected in step 412.

Previous moving speed V _{j-1 m} and current moving speed V
_{When jm} is equal to each other, that is, when the speed is constant, the process _proceeds to step 406, the current value I _ji is detected, and in step 408, the detected current value I _{j-1 i} of the servo motor 21 to 26 of each axis is detected. Is greater than or equal to the current value I _ji . If the determination is NO, the process proceeds to step 422, and the current value i is set as the current maximum load current value Mi. At the start of current monitoring, the determination at step 408 is NO, so the processing at step 422 is executed.

If the determination in step 408 is YES, the process proceeds to step 420, and the current maximum load current value M _i set in step 422 is stored as the maximum load current value I _Vi in the constant speed state.

Step 410 and step 412
When the current value I _ji is detected at step 414 and 416, the detected servo motor 21 of each axis is detected.
To current I _{j-1 i} before the 26 present current I _ji
Greater than or equal is determined. If this determination is NO, the routine proceeds to step 422, where the current value i is set as the current maximum load current value M _i . At the time of starting the current monitoring, the above steps 414 and 416
Since the determination is NO, the process of step 422 is executed. Step 424 and Step 426
If the determination is YES, step 42
4, the current maximum load current value M _i set in step 422 is stored as the maximum load current values I _mi and I _ni in the acceleration state and the deceleration state.

The current monitor process including steps 402 to 426 is executed in parallel with the movement control in step 302.

In step 306, it is judged whether or not the work is the second work. In the case of the second work, in step 308, the maximum allowable load current I ₀ and the constant speed of the servomotors 21 to 26 of the respective axes monitored in step 304 are monitored. Load margin ratio a _vi (= I _0), which is the ratio of the maximum load current values I _vi , I _ni , and I _{mi in the} states, acceleration states, and deceleration states.
/ I _vi ), a _mi (= I ₀ / I _mi ), a _ni (= I ₀ /
Calculates the I _ni), a load margin ratio a _vi, a _mi, a _ni minimum a _v a, a _m, seek a _n. Next, the acceleration A _m , the deceleration A _n and the speed V _m are calculated from the fixed acceleration a ₀ and the fixed speed V _{0 according} to the following _equation 9, and the memory 402
Stored in the SDA area of.

(Equation 9)

In step 312, the acceleration A _m , the deceleration A _n, and the speed V _m calculated as shown in FIG.
The movement control shown in 13 is executed. In FIGS. 12 and 13, the same steps as those in FIGS. 4 and 5 of the above-described first embodiment have the same step numbers. In FIG. 12, in step 205, the SD of the memory 402 in step 308.
Acceleration stored in the A area A _m, deceleration A _n, velocity V _m
Is different in that it reads out. In this step 205, memory 4
Acceleration A _m , deceleration A _n , and speed V _m read from No. 02.
Based on, the movement control is executed with the same value until the work is switched. Further, FIG. 13 is the same except that steps 220 to 226 in FIG. 5 are not provided.

In the case of the second line, FIG.
In step 205 shown in, reading the acceleration A _m stored in the memory 402, the deceleration A _n, the velocity V _m,
The movement control is executed similarly to the step 312.

In the robot controller according to the second embodiment, the maximum load current storage means 42 monitors the current change in one cycle of the acceleration section, the deceleration section, and the constant velocity section when the work is switched, and the maximum load current storage means 42 monitors each work. The maximum load current in each of the robot acceleration state, constant speed state, and deceleration state is stored, and the load margin ratio is calculated based on the maximum load current in each state for each workpiece, so the robot acceleration state , The constant speed state and the deceleration state are controlled based on the speed pattern according to each state. In addition, since the same work can be controlled from the second work on the basis of acceleration according to the load margin ratio from the start of movement control, the cycle time can be shortened.

The robot control apparatus of the second embodiment having the above-described operation calculates the load margin ratio based on the load current in one cycle of the acceleration section, the deceleration section, and the constant velocity section when the work is switched, and the load margin ratio is calculated. The servomotor for each axis is controlled based on the margin ratio, and is controlled based on the speed pattern corresponding to each state of the robot such as the acceleration state, the constant velocity state, and the deceleration state, so that the operation locus does not change. Further, there is an effect that accurate and optimum adaptive control is possible.

The above-described embodiments have been described by way of example only, and the present invention is not limited to these embodiments. Those skilled in the art will recognize from the claims, the detailed description of the invention, and the drawings. Modifications and additions are possible without departing from the technical idea of the present invention.

For example, in the above-described embodiment, an example in which the maximum load current is detected by comparing the magnitudes of the load current values output from the load current detecting means has been described.
The present invention is not limited to these, and for example, the gradient of the load current is calculated by differential processing or the like to detect the maximum load current, or other methods can be adopted.

Further, in the above-mentioned embodiment, the example of the linear interpolation is representatively described, but the present invention is not limited to them. For example, the circular interpolation can be carried out by the same procedure. That is, when the central angle is Γ and the radius is r in the arc, the substitution may be made based on the following equation 9 in the above equation.

(Equation 10) However, Ωm is the angular velocity of the central angle of circular interpolation, and Π is the angular acceleration of the central angle.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment device in the present invention.

FIG. 2 is a block diagram showing a configuration of a control device of the first embodiment device.

FIG. 3 is a flowchart showing a main processing procedure of instruction word decoding by the host CPU.

FIG. 4 is a flowchart showing a processing procedure for determining an interpolation angle by a host CPU.

FIG. 5 is a flowchart showing a processing procedure of speed control by a host CPU.

FIG. 6 is an explanatory diagram showing an operation program.

FIG. 7 is an explanatory diagram showing an operation path.

FIG. 8 is a diagram showing a change in load current in the device of the first embodiment.

FIG. 9 is a diagram showing a velocity pattern in the device of the first embodiment.

FIG. 10 is a workpiece switching control flowchart of the second embodiment device of the present invention.

FIG. 11 is a flowchart of a current monitor of the second embodiment device.

FIG. 12 is a movement control flowchart of the second embodiment device.

FIG. 13 is a speed control flowchart of the second embodiment device.

FIG. 14 is a diagram showing a speed pattern of a conventional device.

FIG. 15 is a diagram showing a change in load current of a conventional device.

[Explanation of symbols]

 1 Robot 2 Motor 4 Control Device 5 Servo Driver 21-26 Servo Motor 61-66 Current Detector 400 Host CPU 402 Memory

Claims (3)

[Claims] 1. A robot for positioning a robot hand at a teaching point given according to a movement trajectory, wherein a moving speed is based on a fixed acceleration allowable by a motor for driving the robot when a maximum load is applied. In a controller of a robot having a control means for controlling the movement operation of the robot by determining a load current detecting means for detecting a load current of the motor for driving the robot, and a maximum allowable load current of the motor is stored. Maximum allowable load current storage means, load margin value calculating means for calculating a load margin value from the maximum allowable load current of the motor and the maximum load current when the robot operates at the fixed acceleration, And an acceleration calculation means for calculating an acceleration for determining the moving speed based on the load margin value and the fixed acceleration. Control apparatus for a robot according to claim and. 2. A robot for positioning a robot hand at a teaching point given according to a motion trajectory, wherein a plurality of motors provided on respective axes are allowed to drive the robot when a maximum load is applied to the robot. A robot controller having fixed acceleration storage means for storing possible fixed accelerations, and control means for controlling a moving operation of a robot by determining a moving speed based on the stored fixed accelerations. Load current detection means for detecting load currents of the plurality of motors for driving, maximum allowable load current storage means for storing maximum allowable load current of the motor, and when the robot operates at the fixed acceleration. A maximum load current storage means for storing the maximum load current detected by the load current detection means, a maximum allowable load current of the motor, and Load margin ratio calculating means for calculating a load margin ratio from the ratio of the maximum load current, and acceleration calculation for calculating an acceleration for determining a moving speed for driving the plurality of motors based on the calculated load margin ratio. And a control device for the robot. 3. The robot control device according to claim 2, wherein the maximum load current storage means stores maximum load currents in an acceleration state, a constant speed state, and a deceleration state of the robot.