JPS59706A - Controller of industrial robot - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a control device for an industrial robot, and more particularly to an industrial robot control device that accurately positions the tip of a robot.

[Background of the invention]

The prior art will be explained with reference to FIGS. 1 and 2.

FIG. 1 shows a side view of the robot projected onto the xz plane, a top view of the same robot projected from above onto the xy horizontal plane, and FIG. 2 shows a control circuit diagram. P.

Q and R are connection points of operating axes connected in series in order to be able to move arbitrarily within the work space, respectively, and F is the tip point of the robot. eI=pQ.

/2=QR, and θ1 is such that the plane containing l+ and 12 is
The angle between the y-horizontal plane and the X-axis, θ2 is the angle between the vertical axis passing through point P and l
The angle between + and θ3 is the angle between 12 and the extension line QQ' of l+. Now, assuming that 11 and 12 are each a constant length, the operating amount θ1. θ2. When positioning the robot tip point F by controlling θ3, conventionally, as shown in Fig. 2, the command value of the operation amount θ, (meaning any one of θ5, θ2, and θ3) is The amount of motion is applied to an actuator 2, such as an electric motor or a hydraulic motor, through an amplifier 1, and the amount of motion detected by a detector 3 directly connected to the motion axis is fed back to the input side of the amplifier. The position of point F) was being determined. In this way, conventionally, each motion axis was controlled independently of the other motion axes. In addition, in the description of the conventional example in Section 2, e
It is assumed that L and 12 are constant lengths, but even when L+ and 12 are made into a minus film and have six variable lengths, conventionally a method has been adopted in which each variable amount is controlled independently.

However, in the case of a robot having a plurality of motion axes, the load applied to the actuator of each motion axis varies greatly depending on the position and orientation specified in space. For example, in the case of FIG. 1, the influence of the load mass M at point R on point P varies greatly depending on the magnitude of θ3. That is, the robot tip point F
Both θ2 and θ3 have a joint influence on the positioning accuracy in relation to each other. In order to cope with this, it has also been practiced to calculate the rotational moment l that causes the load mass M at the point R to be χ;1 at the point P, and to perform control using this calculation result. That is, in FIG. 1, let /-PR be the inclination angle of l as θ2I
Then, the rotational moment I is 1=M-/cosθ2I...
...(1) 1 :lI2+122-21+ 12c
O503...---(2) θ21---θ2-
cos'(u”)・・・・・・・・・(3)2
It is indicated by 211+.

However, each operation amount θ2. (1) every time θ1 is detected.

(2+, (To calculate and control the rotational moment I using Equation 31, it was necessary to provide a complicated calculation circuit.In addition, in the conventional circuit shown in Fig. 2, each operation amount θ is independently controlled. Even when controlling, in order to ensure positioning accuracy at any point in the operating space, setting the amplifier gain according to the position and orientation of the maximum load may cause oscillation when the load is small, so it is necessary to suppress oscillation. There was an inconvenience that positioning accuracy was not guaranteed if the gain was set to .

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an industrial robot control device that solves the above problems of the prior art, has a simple circuit configuration, and can maintain good positioning accuracy.

[Summary of the invention]

A feature of the present invention is that the gain of an amplifier that sends a signal to the actuator of a certain motion axis is controlled not only in response to the motion amount of that motion axis but also in response to the motion amount of other motion axes. be.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG.

In FIG. 3, 10 is a control command section that indicates a plurality of operation amounts θ.
1. θ2. θ3. . . . , each command value of θN is increased by 1'j. 12 and 13 amplifiers sending output signals to actuator 22 at point P and actuator 23 at point Q in FIG. 1, respectively; 32. , 33 are detectors directly connected to the respective operating axes, and 20 is each actuator 22 .
23 shows a robot mechanism driven by the robot mechanism 23. 51,
52 and 53 are arithmetic circuits, sl, s2. s3
is the output amount of each arithmetic circuit 51, 52, 53, 61 is an arithmetic circuit that takes the absolute value 1θ21 of the operation amount θ2, 63 is the absolute value 1θ2+θ31 of the sum θ2+θi of the operation amount θ2 and θ3
An arithmetic circuit that takes k, , k2. k3 are output amounts sl, s2. Indicates the constant to which s3 is multiplied.

The rotational moment given to P by point Q in Figure 1 is the operating amount θ2
Therefore, the rotational moment given by point R to point P is the operating amount θ
Since the gain of the amplifier 12 changes depending on the combined amount of 2 and 03, the gain of the amplifier 12 is determined by the absolute value 1θ2 of the operation amount obtained by the arithmetic circuit 61.
1 is converted into the value of the first quadrant (0≦θ,≦πA) by the arithmetic circuit 51, and the output amount S is multiplied by the proportionality constant kl, which is 1·Sl.
The gain of the amplifier 13 is set to 3·S3, which is obtained by multiplying the output amount S obtained by converting the absolute value 1θ2+θ31 obtained by the arithmetic circuit 63 into the value of the first quadrant by the proportionality constant by 3. Furthermore, in the present invention, the output amount s2 obtained by converting 1θ2+θ31 obtained by the arithmetic circuit 63 by the arithmetic circuit 52
2.s2, which is obtained by multiplying the proportionality constant by 2, is added as the gain of the amplifier 12. By doing this, the calculation formula (1) becomes as complicated as in the conventional example.

(Instead of solving 21, +3+, the motion amount θ1.θ2.θ
3 (In this case, from the configuration of the motion axes shown in Figure 1, θ1
is another θ2. It is possible to achieve highly accurate positioning control by simply controlling .theta.3 (which is controlled separately from .theta.3).

As described above, the arithmetic circuits 51, 52, and 53 calculate the operation amount angle θ1 corresponding to any quadrant from the value of the first quadrant (0≦θ
, ≦π//2). For example, in the arithmetic circuit 51, if θ-1θ21, then when θ<πA
When θl=θ θ>π/2, a function value of θ′−π−θ with θ′ as a variable is output. Similarly, in the arithmetic circuit 53, if θ-1θ2+θ31, first θ>π
When θ'-θ-π, an output similar to that of the arithmetic circuit 51 is obtained. In the arithmetic circuit 52, similar outputs are obtained as θ-1θ2+θ31, 0×θ<π, θ1, θl=θ, and θ>π/2, θ′=π−θ. However, in the calculation circuit 52, θ=0. When θ−π, it is set as θ′−〇. This is the first
In the figure, it means that point R is on the vertical line Q//Q/# passing through point Q, and in this case, the gain of amplifier J2 is the operating amount θ2
Controlled only by. In addition, the arithmetic circuit 52
．． When θ〉π, point R passes through point Q, vertical line QJF Q/
This is a case where the point P is further approached after passing through II, and even if θ'-0 is used in this case, the positioning accuracy will not particularly deteriorate.

When a calculation processor such as a microcomputer is incorporated in the control command unit IO, the operation amount θ2
．． Since θ can be easily processed as a digital quantity, there is no need to provide the absolute value calculation circuits 61 and 63 and the quadrant conversion calculation circuits 5], 52, and 53 in FIG. Shown in Figure 4.

According to the embodiment shown in FIG. 3 or FIG.
It can be controlled by the amount of direct motion corresponding to 1.12.

Depending on the configuration of the robot, or when strict positional accuracy is not required, there is no need to perform continuous control according to the amount of movement, and in this case, as shown in one embodiment in FIG. The output amount S1 is passed through the comparator 30 and adjusted to several preset operating amounts. 1□、・・・・・・
+"in can be selected by a switch 40 that opens and closes in conjunction with the comparator 30 and outputs the selected one.

〔Effect of the invention〕

As explained above, since the present invention is configured to control a plurality of motion quantities, it is possible to perform precise positioning control without the need for complicated arithmetic circuits as in the case of conventional devices. can be done.

[Brief explanation of drawings]

Figure 1 is a side view showing an example of the configuration of the mouth and pot;
FIG. 2 is a conventional positioning circuit diagram, and FIGS. 3, 4, and 5 are circuit configuration diagrams showing embodiments of the present invention, respectively. Explanation of the scoop 10...Control command unit 12.13...Amplifier 20...Robot mechanism 22.23...Actuator 30...Comparator 32.33...Detector 40...Switch 51 , 52.53.6] , 63...Arithmetic circuit agent Junnosuke Nakamura〒 1 (￥) '7V211D Left 3, Leap

Claims (1)

[Claims] In an industrial robot that has a plurality of operating axes connected in series in order to be able to move arbitrarily within a work space,
A detector for detecting the motion amount of the motion axis, an amplifier for amplifying the deviation signal between the detected motion amount and the command motion amount, and a drive means for driving the motion axis according to the output of this amplifier are provided for each motion axis. . An industrial robot control device, wherein the amplification gain of an amplifier provided for each of the operating axes is controlled in accordance with the amount of movement of the other operating axes.