JPH03296107A - Robot controller - Google Patents

Abstract

PURPOSE:To form an optimum system according to the number of joints of a robot by making a main processor share the functions of a track generation part and a mechanism conversion part and also secure an interface to a work condition setting part and controlling the number of servo processors in response to the number of robot joints. CONSTITUTION:A main processor 10 operates an interpolation point to secure the connection between the present and 16 target positions of a robot to be controlled through a track generating part 17 based on the contents shown by a work condition setting means 20. Then the processor 10 operates the angle of each joint to attain those present and target positions of the robot through a mechanism conversion part 17. Meanwhile a servo processor 40 contains the position/speed control part for each joint of the robot. Each of these position/speed control part operates a finer secondary interpolation point through a higher-order operation that presents a smooth curve based on an interpolation point given via a bus. Then the processor 40 controls the angles of robot joints in order to drive the robot on its target track. Thus it is possible to obtain an inexpensive robot controller that can be widely applied to the robot to be controlled through a smooth robot track.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to improvements that increase the versatility and controllability of a robot control device.

<Prior Art> A robot control device is known from Japanese Patent Laid-Open No. 62-232.006 (tJsP No. 4,833,624).

FIG. 5 is a functional block diagram of a conventional device. In the figure, in the work condition setting section, the initial position regarding the hand to robot 1!
Specify (X, Y, Z), moving speed F, waypoints, target position, etc. The trajectory generation section calculates the movement trajectory of the robot from the points P sent from the work condition setting section, and uses interpolation points Q to specify in detail between the designated points P using linear interpolation or circular interpolation.

The m-configuration conversion unit calculates the joint rotation angle Q'' that realizes the interpolation point Q calculated by the trajectory generation unit, and depending on the type of robot to be controlled, it can be used for cylindrical coordinates, horizontal joints, or orthogonal coordinates. The suitable one is selected from among the vertical joints and vertical joints.The position/velocity control section uses the joint rotation angle Q obtained by the mechanism conversion section.
'' is executed smoothly, and the command value R is sent to the robot 1, and the actual joint angles of the robot 1 are adjusted back to improve controllability.

Conventional devices usually perform distributed control using multiple processors. For example, in the above-mentioned application, the main processor is in charge of the work condition setting section, and the sub-processor is responsible for the trajectory generation section, mechanism conversion section, and position/speed control section. It is in charge.

When there are a plurality of robots to be controlled, a sub-processor is provided for each robot, and a main processor is provided in common to enable cooperative operation of the robots.

<Problems to be Solved by the Invention> FIG. 6 is an explanatory diagram of interpolation calculations of a conventional position/velocity control section. Interpolation points Qi, Qi+1, Ql+2 from the trajectory generator
It is sent in coordinates or time series. The time interval between these interpolation points is, for example, 20 m5, and the position/velocity control section performs linear interpolation to obtain more detailed quadratic interpolation points R, . . . , Ri.
, 10, and control 1.1. Set the interval to, for example, -2 ms.

However, in linear interpolation, when interpolation points are given to represent arcuate curves, there is a problem in that the trajectory obtained by quadratic interpolation becomes a polygon. On the other hand, it is possible to use curve interpolation for -order interpolation because the subprocessor performs calculations for the trajectory generation section and position/velocity control section in a time-sharing manner, so there may be a problem of insufficient calculation time. .

In addition, it has been conventional practice to provide a dedicated control device for each robot to be controlled, but in factories and other places where the robot is used, the control device is managed differently for each robot introduced. The problem was that it became complicated.

The present invention solves these problems and provides a low-cost robot control device that can be used universally for the robot I to be controlled and that allows the robot I to have a smooth trajectory. The purpose is to

Means for Solving the Problems> FIG. 1 is a configuration block diagram illustrating the present invention that achieves the above objects. In the figure, the main processor (10) is
A file (15) that stores information from the work condition setting means (20) that defines the initial position, target position, movement speed, etc. of the robot, and interpolation points are calculated for the target position described in this file. The robot 1 includes a trajectory generating section (16) for calculating the interpolation points obtained by the trajectory generating section, and a mechanism converting section (17) for calculating the joint angles of the robot 1 to realize the interpolation points determined by the trajectory generating section.

The servo processor (40,) calculates a quadratic interpolation point by high-order calculation on the interpolation point sent from the trajectory generation unit provided for each joint of the robot, and calculates the quadratic interpolation point and the interpolation point. The position/velocity control unit for at least one joint sequentially controls the angle of the joint using the target value as a time-series signal. Here, since the robot has six joints, it is equipped with six position/velocity control units or one servo processor.

The bus connects the main processor and the servo processor, and sends information such as interpolation points and target positions of the main processor to the servo processor.

Functions Each component of the present invention has the following functions. The main processor calculates an interpolation point connecting the current position and the target position for the robot to be controlled in accordance with the contents instructed by the work condition setting means in the trajectory generation part, and each joint that realizes this position in the mechanism conversion part. I am looking for the angle of Based on the interpolation points given via the bus, the position/velocity control section calculates finer quadratic interpolation points by high-order calculations that provide a smooth curve, controls the angle of the joint, and The 6 position/speed control units that allow the robot to move along the target trajectory are provided according to the number of joints on the robot 1, so the number of servo processors is adjusted to obtain quadratic interpolation points with the required precision. It is good to select.

<Example> The present invention will be explained below using the drawings.

FIG. 2 is a block diagram showing an embodiment of the present invention. In the figure, the work condition setting section 20 is a programming console 21 in charge of the man-machine interface.
, a teaching box 22 used for teaching the robot, and a programmable controller (PC) 23 whose operation contents are predetermined. These devices send the initial position, target position, necessary waypoints, and movement speed to the main processor 10, and also send the information of the robot to be controlled. We provide structural conversion formulas suitable for fA construction.

The main processor 10 includes a language interpreter 11 for controlling the robot 1 such as BASIC and a control language, and an execution area TI for parallelizing two tasks at the same time.

Common area 1 that enables T2 and mutual data exchange
It has 4. Note that a compiler-type language may be used in place of the language interpreter 11, and when only a single task is executed, only one execution area is required, and the common area 14 may also be omitted. The file 15 is temporarily stored with information sent from the work condition setting section 20, and here, in order to speed up reading and writing, the file 15 is a ram disk (
RAMDISK) and language interpreter 11
or access and interpret the stored contents.

The trajectory generation unit 16 calculates interpolation points using a predetermined calculation formula (for example, a spline curve) for the target point of the file 15 sent via the language interpreter 11, and calculates interpolation points from time to time on the trajectory with respect to the target point. I am looking for the position and posture at every moment. The mechanism conversion unit 17 calculates the joint angles of the robot l- to realize the interpolation points determined by the trajectory generation unit 16, and calculates the rotation angle (number of pulses) of the motor provided at each joint at each moment. . The input/output control section 18 manages human output of contact signals and analog signals.

The T10 processor 30 specializes in managing input/output and reduces the load on the main processor 10. The data conversion unit 31 converts data between the input/output control unit 18 and each device, and performs, for example, scaling and ribbing. Transistor/relay output and DC input are used for switches and relays, and R32 is used for PCs and computers.
A communication line such as 32C is used, and the sensor uses analog input/output. For example, a visual sensor or a tactile sensor is connected here, and serves as a feedback signal for the robot control device.

The servo processor 40 has a position/speed control section provided for each joint of the robot. The position/velocity control unit performs high-order calculations (other than linear interpolation, such as circular interpolation, quadratic curve, or polynomial approximation of third or higher order) based on the auxiliary points obtained by the trajectory generation unit 16, and It has a spline interpolation unit 41 that calculates the next interpolation point. Spline interpolation involves assigning a plurality of four points to a predetermined equation to obtain the required trajectory equation, and selecting secondary auxiliary points from points that satisfy this equation. The adder/subtractor 42 uses this secondary auxiliary point as a target value and the signal from the pulse integrator 47 as a detected value, and calculates the deviation between the two.

The position control section 43 inputs the signal from the adder/subtractor 42, and outputs a position control signal to the adder/subtractor 44 if it is necessary to further rotate the joint to be controlled. The adder/subtractor 44 uses this position control signal and the detection signal from the speed detector 46 to
Calculate speed deviation. The speed control unit 45 outputs a command to the servo driver 50 so that the movement speed is within a predetermined range. The servo driver 50 amplifies the command output and drives the motor 51. Then, since the joint rotates, the encoder 52 is used to detect whether the rotation is short or not, and this is fed back to the servo driver 50. Furthermore, the detection signal of the encoder 52 is
The encoder feedback signal is used by the speed detection section 46 to detect the current speed, and by the pulse integration section 47 to detect the current position.

Note that the number of servo processors 40 is determined depending on the number of joints to be controlled, the calculation time of quadratic interpolation points, and the ability of the servo processors 40. For example, one servo processor 40 may be used for two position/speed control units. should be established.

The system bus is main processor 10, I10 processor 3
The servo processor 40 is connected to the servo processor 40 as well as the servo processor 40, and commands/buttons are exchanged with protocols 1 to 1. Since each processor can operate autonomously, the transmission speed may be low. As a result, there is an advantage that the hardware load on the bus interface is reduced and that it can be extended over long distances.

The operation of the device configured in this manner will be described next. The main processor 10 loads the target user program on the file 15 into the execution area and executes it in accordance with a startup command from the programming console 21 or the like. When performing parallel operations, both execution areas Tl and T2 are used, and a common area is used for mutual data exchange. The trajectory generation unit 16 coordinately controls the servo motors of each joint, and calculates the trajectory from the position and orientation given by the language interpreter 11.The mechanism conversion unit 17 calculates the rotation speed of the motor, and It is given as a command value to the controlling servo processor 40 via the bus.

The servo processor 40 has a software servo type position/speed control section, and when the servo driver 50 is a torque input type, it performs position/speed control, and when it is a speed input type, it performs only axis position control. The spline interpolation section 41 uses a spline function to interpolate the rotation angle of the motor given from the trajectory generation section 16, thereby making the operation extremely smooth during high-speed operation. FIG. 3 is an example in which a certain joint is interpolated using a cubic equation, with time 1 being plotted on the horizontal axis and joint angle θ being plotted on the vertical axis.

In the figure, black dots are auxiliary points and solid lines are interpolation curves, and quadratic auxiliary points are selected on this curve. FIG. 4 is a diagram showing the positions of the hands of the robot. Linear interpolation results in a polygonal shape, but cubic interpolation using the spline interpolation unit 41 yields a much better locus.

In the above embodiment, the main processor 10 is described as one, but functions may be distributed among a plurality of processors. Further, the number of axis position/speed control units mounted on the servo processor 40 may be one axis/unit, or more than one axis/unit.

<Effects of the Invention> As explained above, according to the present invention, as shown in FIG.
The robot processor 40 can be increased or decreased depending on the number of joints, so an optimal system can be configured according to the number of joints of the robot. can. Furthermore, since the servo processor is dedicated to quadratic interpolation, it has the effect of being able to calculate quadratic interpolation points in a short cycle, making full use of the processor's capabilities.

[Brief explanation of drawings]

Fig. 1 is a block diagram illustrating the present invention that achieves the above object, Fig. 2 is a block diagram illustrating an embodiment of the present invention, and Fig. 3 is a block diagram illustrating a joint using a cubic equation. The explanatory diagram, FIG. 4, is a diagram showing the position of the hand toward the robot 1. FIG. 5 is a functional block diagram of a conventional device, and FIG. 6 is an explanatory diagram of interpolation calculations of a conventional position/velocity control section. 10... Main processor, 15... File, 16.
...Trajectory generation unit, 17...Ils conversion unit, 20...
Working conditions ≦ 1 hour E-@6

Claims (1)

[Claims] A file that stores information from a work condition setting means that defines the robot's initial position, target position, movement speed, etc., and a trajectory that calculates interpolation points for the target position described in this file. a main processor comprising a generation unit, a mechanism conversion unit that calculates joint angles of the robot that realizes the interpolation points determined by the trajectory generation unit, and an interpolation point sent from the trajectory generation unit that is provided for each joint of the robot. A position/velocity control unit for at least one joint that calculates a quadratic interpolation point by high-order calculation for the target and controls the angle of the joint by sequentially using the quadratic interpolation point and the interpolation point as a target value in time series. a bus that connects the main processor and the servo processor and sends information such as interpolation points and target positions of the main processor to the servo processor. Control device.