JPS5922104A - Method and device for controlling movable arm of robot - Google Patents

Abstract

PURPOSE:To perform high-precision position control by calculating the speed and displacement of the tip part of the movable arm of a robot from the detected acceleration of the tip part. CONSTITUTION:A detector 5 is provided near a working part 4 which is the tip part of the movable arm 3 to detect the acceleration of the tip part, and the speed and displacement of the tip part are calculated by processing the detected acceleration as a function of continuous time. Those calculated speed and displacement of the tip part are compared with values corresponding to a preset speed and a preset position and the tip part is driven to the set position on the basis of the comparison results.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for controlling a movable arm of a robot, and more particularly to a method and apparatus for detecting and controlling the position of the tip of the movable arm.

Generally, a robot movable arm is controlled so that the tip of the movable arm moves to a predetermined position to perform a required work operation.

In order to correctly control a robot's movable arm, it is necessary to accurately detect the position of the tip of the movable arm, and conventionally, various means have been taken for this purpose depending on the structure of the movable arm.

In a conventional movable arm control means having an articulated robot movable arm as shown in FIG. joint e
, f are each provided with a rotation angle sensor, and the position of the working part d as the tip is detected from the rotation angle.

In the conventional movable arm control means having an orthogonal robot movable arm as shown in FIG. The position of d is detected.

However, in these conventional means, the sensor is located at a distance from the working part d as the tip and its position is detected. If deflection occurs up to the working part d, there is a problem that the position of the tip cannot be accurately detected.

One way to deal with this is to increase the rigidity of the movable arms, but this would make Robono I's arms heavier, and the main body that supports them would also have to have a heavier structure, which would make the robot as a whole heavier. There is one problem.

Furthermore, with these conventional means, due to the effects of free vibration of the movable arm and deformation of the arm due to the load held by the tip d,
There is also the problem that highly accurate position detection and control cannot be performed.

Therefore, as a means to improve accuracy, there is a conventional method in which multiple sources of position signals are installed outside the robot, and a sensor installed at the tip of the robot detects the position signals to perform highly accurate position detection. Although such methods have been developed, there is a problem in that they lose the degree of freedom inherent in robots, and there are many restrictions on their use.

The present invention aims to solve these problems.
By calculating the speed and displacement of the tip of the robot movable arm from the acceleration detected at the tip, it is possible to accurately detect the position of the tip of the movable arm, and the speed and displacement are instantaneous and continuous. It is an object of the present invention to provide a method and apparatus for controlling a movable robot arm, which enables real-time automatic control of the movable arm of the robot.

This method of controlling a movable robot arm of the present invention first detects the acceleration of the tip of the movable arm when driving and controlling the tip of the movable arm, and then converts the detected acceleration into a continuous time function. The speed and displacement of the tip are calculated, the calculated speed and displacement are compared with values corresponding to the preset speed and position, and based on the comparison results, the speed and displacement of the tip are calculated. of"-
It is characterized in that it is controlled so as to be driven to the set position as described above.

Furthermore, the robot movable arm control device of the present invention includes a drive source for driving the distal end of the movable arm, and a detector having an accelerometer for detecting the acceleration of the distal end of the dual movable arm. a computing unit that calculates the velocity and displacement of the tip by calculating the acceleration detected by the detector as a function of time, and divides the position of the double tip; and the tip of the movable arm. A setting device that sets the position of the movable arm is compared with the position calculated by the dual computing device and the position set in the dual setting device to move the tip of the movable arm to the dual set position. A dual detector is provided at the tip of the movable arm, and includes a comparator wired to send a control signal to the movable movable source.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method and apparatus for controlling a robot movable arm as an embodiment of the present invention will be described below with reference to the drawings.

3 to 5 show a control device for a robot movable arm according to the present invention. FIG. 3 is an overall configuration diagram thereof, FIG. 4 is an explanatory diagram showing a detector at the tip of the movable arm, and FIG. It is a block diagram of the control device.

As shown in Figure 3, the robot's support column 1, movable arm 2, and
: The movable arm 2 and the movable arm 3 are connected to the joint 7 so that they can move freely.

There is a detector 5 near the working part 4 at the tip of the arm 3.
is installed.

As shown in FIG. 4, the detectors 5 are
Y, 7. Accelerometer 8.9.10 to measure the axial accelerations x, y, z and X respectively.

It is composed of angular accelerometers 11, 12, and 13 that detect angular accelerations 0X, θY, and θZ of 1 dimension. I'm here.

The output from this detector 5 is supplied to a computing unit 14, and the output of this computing unit 14 is supplied via a comparator 15 to the drive σ) 21G of the robot movable arm.
Furthermore, the arithmetic unit 14 is supplied with the set time t, which is the output from the reference time setter 17, and the comparator 15 is supplied with the work position X, which is the output from the target coordinate setter 18. +Vn+Zn and working time t
o is supplied.

! Also, the target coordinate setter 18 is also supplied with a preset working posture (rotation angle).

By the way, the position and d used here are - fixed points determined by the spatial coordinate system (X, Y, Z), and the displacements are the two positions (XI + V I + Z 1) and ( The deviation in ((X2+ )′2+ 22 )
X+ ), (ys-y+), (
22y, 1) l −.

The posture is the rotation angle (θX, θY, θZ) around the X axis, Y yoke+, ZIll+, and the angular displacement and the two postures (θXI+ θYI+θ, 1) and (θX2
1θY2+07.2) ((θX, -〇X1
).

(θY2'Yl), (θZ, -θZ,))
is the angle of

Since the robot movable arm control device of the present invention is configured as described above, when the working part 4 as the tip of the movable arms 2 and 3 moves, its accelerations X, y, Z and angular acceleration θX
+OY +θZ is the accelerometer 8 as the detector 5
．． 9.10 and the angular acceleration side 11, 12.13.

Then, the detection of acceleration X'+3'+Z' and angular acceleration OX+'Y+θ as this instantaneous value,
, are supplied to the arithmetic unit 14.

The calculator 14 integrates the acceleration X+ Y+ Z and the angular acceleration θX+ i''Y, θl within the required reference time to determine the current detected position X+ of the working part 4 as the tip.
: Calculate V+Z and detected attitude (rotation angle).

The detection position X+3'+Z of the working part 4 is the comparator 15
The comparator 15 compares this detected position 8°).

Deviation signals ΔX, Δy, and ΔZ are sent to the drive source 16 according to (y yn ), (Z z, ), and time 1o.

Depending on the magnitudes and positive/negative signs of the deviation signals ΔX, Δy, and ΔZ, the driving force of the driving source 16 is 1. 'X, I'Y・p
z, and the movable arms 2 and 3 of the robot are driven so that the working parts 4 of the robot movable arms 2 and 3 reach the target working position.

However, the drive source 16 can also correct the deviation between the detected posture and the working posture.

By the way, in the robot movable arm control method of the present invention, the working parts of the movable arms 2 and 3 are controlled at the required time interval t so that the error between the detected displacement by the integration of acceleration and angular acceleration and the actual displacement does not accumulate. 4 is interrupted, and the tip of the movable arm 2.3 is returned to a predetermined origin (for example, a fixed point away from the working position).

The position corresponding to this origin is stored in advance in a memory or the like (not shown), and this set position is compared with the position corresponding to the detected displacement at the time of return to calibrate this detected displacement. ing.

After performing this calibration, the distal ends of the movable arms 2 and 3 are returned to the working position before the work was interrupted, and the interrupted work operation is resumed.

Furthermore, in order to calibrate the acceleration X + 3' + bar degree angular acceleration '' The work is interrupted, and the tip is caused to pass through two preset points (for example, two fixed points distant from the work position) in a predetermined motion.

At this time, the velocity, angular velocity, displacement, and angular displacement that are detected and determined by integration are compared with the accurate velocity, angular velocity, displacement, and angular displacement that have been set in advance, and the error and Calibrate the sensitivity.

1. After this calibration, the tips gl of the movable arms 2 and 3 are returned to the working position before the work was interrupted, and the interrupted work operation is resumed.

By automatically performing such calibration at the required time interval t, errors will not accumulate even if the robot's movable arm is controlled for a long time, and it will not only be possible to calibrate the position but also to improve the sensitivity of instruments 8 to 13. Since the robot can also be calibrated, the robot's movable arm can be controlled with high precision.

Note that a high-response rate gyro may be used as the angular acceleration side 11, 12, 13.

As described in detail above, according to the robot movable arm I control device of the present invention, the position of the tip of the movable arm that requires position control is determined by the accelerometer and angular accelerometer provided at the tip. Direct detection is possible, and even if the movable arm is deflected, the position of the tip can be accurately detected, which has the advantage of being able to reduce the weight of the movable arm, and the robot body that supports this movable arm can also be made smaller. It is also lightweight, eliminates the effects of free vibration of the tip of the movable arm and displacement due to deformation of the arm when holding a heavy object, and enables highly accurate position control.

Furthermore, according to the method for controlling a robot movable arm of the present invention, position errors and instrument sensitivity can be calibrated by simply passing the origin or between two points at predetermined time intervals, resulting in highly accurate position control. It has the advantage of being possible.

[Brief explanation of drawings]

1 and 2 are elevational views of conventional articulated and orthogonal robot movable arms, respectively, and FIGS. 3 to 5 illustrate an embodiment of the present invention and a method for controlling a robot movable arm according to the present invention. Fig. 3 is an overall configuration diagram of the device, Fig. 4 is an explanatory diagram showing a detector at the tip of its movable arm, and Fig. 5 is a 7672 diagram of its control device. ■...Strut, 2, 3...Movable arm, 4...Working part as tip, 5...Detector, 6.7...Joint, 8,9.10
・・x, y, z direction accelerometer, 11, 12.13 ・・x
, y, z axis rotation υ angular accelerometer, 14... Arithmetic unit, 15...
・Comparator, 16... Drive source, 17... Reference time setter,
18...Target coordinate setter. Agent Patent Attorney Yoshihiko Iinuma

Claims (1)

[Scope of Claims] (1) In a robot having a movable arm whose tip is driven and controlled by a drive source, when driving and controlling the tip, first the acceleration of the tip is detected, and then the detected acceleration is detected. The calculated acceleration is calculated as a continuous function of time, the velocity and displacement of the dual tip are calculated, and the calculated velocity and displacement are combined with the values corresponding to the preset force, velocity, and position, respectively. A method for controlling a robot movable arm, comprising comparing the two ends and controlling the two end portions to move to the set position based on the comparison result. (2) Detect the angular acceleration of the tip, then calculate the detected angular velocity as a continuous time function to calculate the angular displacement of the tip, and combine this calculated angular displacement with the The robot according to claim 1, wherein the robot compares the set posture with a value corresponding to the set posture, and controls the dual tip portion to move to the set posture based on the comparison result. How to control movable arms. (8) In order to eliminate the error between the calculated displacement and the actual displacement, the tip of the movable arm is moved to a predetermined origin at required time intervals during the robot's work operation. The robot according to claim 1 or 2, wherein the robot returns to the working operation after calibrating the calculated displacement based on the actual position of the origin. How to control movable arms. (4) In order to eliminate the errors between the detected acceleration, velocity and displacement calculated as a function of time and the actual acceleration, velocity and displacement, the necessary The tip of the movable arm is moved to pass two predetermined fixed points at each time interval, and the calculated acceleration is calculated based on the actual instantaneous acceleration, velocity, and displacement between the two fixed points. After calibrating the calculated acceleration and calibrating the speed and displacement by calculating the calculated acceleration as a function of time, the "double robot I." is returned to the working operation, as claimed in claim 1. The method for controlling a robot movable arm according to any one of items 3 to 3. (5) Detection in a robot that has a movable arm whose tip is driven and controlled, and which has a drive source that drives the tip of the movable arm and an accelerometer that detects the acceleration of the tip of the movable arm. an arithmetic unit that calculates the velocity and displacement of the tip by calculating the acceleration detected by the detector as a function of time, and subtracts the position of the tip;
- Compare the position calculated by the setting device that sets the position of the tip of the movable arm with the position calculated by the calculator above with the position set in the setting device. and a comparator wired to send a control signal to the dual drive source to drive the robot to a position, the detector being provided at the tip of the movable arm. Arm control device. (6) The detector described in - is provided with an angular accelerometer for detecting the angular acceleration of the tip of the movable arm, and the angular acceleration detected by the angular accelerometer is calculated and processed as a function of time to calculate the angular acceleration of the tip of the movable arm. and ``-a computing unit for calculating the attitude of the light distribution end, a setting machine for setting the attitude of the tip of the movable arm, and the attitude calculated by the computing unit.'' - Compare the tip of the movable arm with the posture set on the position setting device.
- A comparator connected to send a control signal to the drive source to drive the movable arm of the robot to the set posture.