JPS60214018A - Positioning controller - Google Patents

Abstract

PURPOSE:To stabilize a positioning speed by correcting the difference signals between position signals on the basis of the rate of the reference speed reduction ratio of the moving part of an industrial robot and an actual speed reduction ratio. CONSTITUTION:A signal from a position detector E is added AD1 to a command position signal from a control part C to obtain a speed command signal. This signal is added AD2 to an actual detected speed signal to drive a motor M through an amplifer so that the difference is eliminated, thereby rotating the fulcrum RJ of a robot arm to a specific position. For the purpose, a storage part 1 for storing the speed reduction ratio of an actual speed reduction ratio at every fine rotational angle position within the movable range of said fulcrum RJ and the reference speed reduction ratio and a correcting circuit 2 which multiplied the speed signal from the adder AD1 by the speed reduction ratio read out according to the rotational position of the fulcrum RJ are provided. Consequently, a speed command signal to the motor M is large where the actual speed reduction ratio is large and stable speed control is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a positioning control device for positioning, for example, a control device of a Japanese bot.

[Prior art]

Conventionally, as a positioning control device for a robot control device,
There is one disclosed in Japanese Patent Publication No. 5B-43220%.

This will be explained using FIG. 1. In the figure, (a) is.

A control unit that outputs a step-like command position signal,
(Gl) is a well-known gear type reducer that decelerates the rotation of this morph wholesaler, (RJ) is this reducer (
G1) is the fulcrum of the robot arm driven by G1), (T) is a speed detector such as a tacho generator connected to the motor (T), and (G1) is connected to the fulcrum (RJ);
A position detector such as an encoder (ADI) that detects the position of the trout and outputs a detected position signal compares the command position signal from the control unit (0) with the detected position signal from the position detector (trout). The adder (ADII) outputs the difference signal as a speed command signal, and the (ADII) is an adder that compares the deceleration command signal from the adder (ADI) and the detected speed signal of the speed detector (T), and outputs the difference as a signal. (AMP) is a motor so that the difference signal from this adder (ADII) becomes zero)
This is an amplifier that drives the .

Next, the operation will be explained. First, the control section (c
The command position signal Vc from l is added to the detected position signal from the position detector (g) in an adder (ADl), so the adder (ADI) calculates the difference between the two and the speed command. Output as . This speed command is added to the actual detected speed signal in an adder (AD2), and the difference signal is used to drive the motor (b) from the amplifier (AMP) VC so that it becomes zero. The fulcrum (RJ) of the arm is driven via a reduction gear (()l) and rotated to a predetermined position. By the way, the position detector (K) is located at the fulcrum (RJ) VC
Since they are connected together, the position of the arm itself cannot be reliably detected, and the detected position signal is fed back to the adder (ADl) VC. In this case, a gear type reducer (()l)
Since the speed reduction ratio is always constant, the output signal to the motor (driving the fulcrum (RJ')) is always controlled in speed based on a constant constant. In other words, even if the position of the robot arm changes moment by moment, a constant constant is always given to the speed command signal.

However, when the deceleration mechanism shown in FIG. 2 is used in the VC, the following problems occur. Next, let me explain about Figure 2. In the figure, (G2) is a speed reduction mechanism consisting of a ball screw, which includes a threaded rod (Gza) driven by a motor (M), a nut portion (G21) that moves by the rotation of this threaded rod (Gza), and this Nut part (G2b
) and the fulcrum of the arm (R, T) (G2
C).

For devices with such a speed reduction mechanism, a patent application filed in 1973
8-212901, so the explanation will be omitted. Now, when considering the reduction ratio of the reduction mechanism (G2), as shown in Fig. 3, the amount of movement of the nut part (G2t) with respect to the threaded rod (Gza) VC is determined by the rotation of the threaded rod (GQa). It is proportional to the number of times, but the nut part (Ggb) and the link (
In order to move on the trajectory of circular motion of G2c), the nut part (
Gsb) Even if the movement #itH is the same, the trajectory of circular motion J
:, Depending on the positions A and B of the nut part (G2b) in the VC, there will be a difference in the movement angle between them, as shown by 01 and 02. That is, the reduction ratio of the reduction mechanism (G2) changes depending on the movement position of the nut portion (Gab).

As a result, the number of the speed command output from the adder (AD) changes depending on the position of the nut (G ab ), resulting in a diamond positioning speed, which has the disadvantage of making speed control unstable. Summary] This invention was made with the aim of improving the above drawbacks, and includes a moving part driven by a drive source via a speed reduction mechanism, a position command signal to this moving part, and an actual position of the moving part. and a control section that controls the movement of the moving section to a predetermined position based on the difference signal, and the reduction ratio of the speed reduction mechanism changes according to the moving position of the moving section, The positioning speed can be stabilized by providing a correction means that corrects the difference signal based on the ratio of the actual reduction ratio at the moving position of the moving section L to the standard reduction ratio in the possible range of the transferring section. This paper proposes a positioning control device that can

[Embodiments of the invention]

FIG. 4 is a block diagram showing an embodiment of the present invention,
il+ is a storage unit (2) that stores the actual reduction ratio for each minute rotation angle position in the movable range of the fulcrum (R, T) of the arm and the reference reduction ratio in the movable range;
) is the deceleration ratio (hereinafter KBj
) is read from the storage section fil and the adder (ADI
) is a correction circuit that multiplies the speed command signal [KBj and outputs the result. Descriptions of other symbols are omitted as they are the same as in the conventional device.

In the device configured as above, the control section (0
) is added to the detected position from the position detector (E) in an adder (ADI), and the difference signal is output as the speed command @. Here, the position detector (
The detection position from 1 depends on the number, and a signal corresponding to the position of the fulcrum (RJ) is input to the storage unit, so the flt
KBj corresponding to tc is output to the correction circuit (2), and this KBj is multiplied by one speed command word, so the fulcrum (RJ
) The difference between the actual reduction ratio and the reference reduction ratio at the position is corrected, and the fulcrum (RJ) is rotated at a stable speed.

That is, at a position where the actual speed reduction ratio is larger than the reference value of the speed reduction ratio in the movable range of the fulcrum (RJ), it is larger than KBj Kl, and conversely, at a smaller position, it is smaller than l. Therefore,
At a position where the actual reduction ratio is large, the speed command to the motor (M) becomes large, and conversely, at a position where the reduction ratio is small, the speed command to the motor (M) becomes small, and the speed command to the motor (M) becomes small at a position where the actual reduction ratio is small. The positioning speed of the arm driven by the arm is constant, and the speed is stably controlled.

Note that if the calculation formula for KBjVi is simple enough to allow high-speed calculation, the storage section is not necessarily essential;
j may be determined by arithmetic processing at any time.

〔Effect of the invention〕

As described above, the present invention compares a moving part driven by a drive source via a speed reduction mechanism, and a position command signal to this moving part with the actual position of the moving part marked L, and the difference therebetween. A controller is provided for controlling the movement of the moving part to a predetermined position π by a signal, and the reduction ratio of the speed reduction mechanism changes according to the moving position of the moving part, and the standard in the possible range of the moving part E is Since the correction means is provided for correcting the difference signal according to the ratio of the actual reduction ratio in the moving part of the moving part to the reduction ratio, changes in the reduction ratio due to the position of the moving part are reliably corrected, and the positioning speed is This has the effect of stabilizing the positioning and improving the coordination of positioning operations.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a conventional device, Fig. 2 is a block diagram showing another example of the conventional device, Fig. 3 is an operation explanatory diagram showing the operation of Fig. 2, and Fig. 4 is an example of an actual structure of the present invention. FIG. 2 is a block diagram illustrating an example. In the figure, +11 is a storage unit, (2) is a correction circuit, (cl is a control unit, (ADl) (AD2) is an adder, true)
ke motor, (G2) is the reduction mechanism, (T)V! Speed detector, (K) is position detector, (AMP) is speed amplifier, (R
J) is the fulcrum. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Agent Masuo OdaiFigure 1Figure 2Figure 3Figure 4

Claims (1)

[Claims] The moving part is driven by a drive source via a deceleration mechanism, and the position command to this moving part is compared with the actual position of the moving part, and the moving part is moved to a predetermined position based on the difference signal. A control unit is provided to control the moving position v of the moving unit.
In the case where the reduction ratio of the reduction mechanism changes over time, the difference signal is corrected based on the ratio of the actual reduction ratio at the movement position of the movement part to the reference reduction ratio in the possible range of the movement part. A positioning control device comprising means.