JPS63214812A - Positioning control device for servo motor - Google Patents

Abstract

PURPOSE:To minimize a residual vibration with a high accuracy by specifying a speed command value as a non-linear function to a position deviation, obtaining a speed command value from the function in accordance with the detecting signal of the position deviation and outputting it to a servo amplifier. CONSTITUTION:The positioning of a servo motor 1 is composed of a speed detecting device 2, a pulse encoder 3, a counter 4, a servo amplifier (speed amplifier) 5 and a D/A-converter 6. The rotation angle signal of the above- mentioned motor 1 is sent to a control device 7, and the speed control of the servo motor 1 is executed by the deviation with a speed command. At the control device 7, a desired speed reducing curve is given as the time function of the position deviation and the relational expression of both is obtained from the time function of a speed obtained by differentiating this and the time function of the above-mentioned position deviation. The speed command value is calculated from the above-mentioned relational expression in accordance with the position deviation of the servo motor 1, and thus, the speed of the servo motor 1 is controlled through the servo amplifier 5.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a positioning control device for a servo motor, and in particular, a highly functional positioning control device for a servo motor suitable for obtaining an arbitrary deceleration curve depending on the application. Regarding.

[Conventional technology]

In the conventional servo motor positioning control device, it is stated from Proceedings Op 11th I-Nis IR (1981), p. 405 that a cam curve is suitable as a deceleration curve for positioning control with low residual vibration. 41st
2 pages (Prooeedings of the 11 t
hl5IR (1981) pp, 405-412)
K has been discussed. However, in this case, the target position obtained according to the cam curve is given to the positioning control device as the command position, and changes in the response due to disturbance during the delay in the response of the servo motor are not fed back to the command position calculation, so the actual The response of the servo motor will be different from the cam curve.

The effect of reducing residual vibration was not sufficient.

In addition, in a normal servo motor positioning control device, the speed command value is proportional to the position deviation or the speed command value is proportional to the 1A power of the deviation. 1/2 of
In the case of proportionality to the power, there was a problem in terms of residual vibration.

[Problem that the invention seeks to solve]

The above-mentioned conventional technology does not give consideration to obtaining an arbitrary deceleration curve that reduces residual vibration, and has problems in terms of response speed and residual vibration.

SUMMARY OF THE INVENTION An object of the present invention is to provide a positioning control device for a servo motor with high accuracy and little residual vibration, which can determine a speed command value as a function of a feedback signal of positional deviation to obtain a required deceleration curve.

[Means for solving problems]

The above purpose is to provide a means for determining a speed command value as a nonlinear function of the position deviation in order to obtain a deceleration curve of the required position deviation with respect to time, and a means for determining the speed command value from the nonlinear function in response to a detection signal of the position deviation to control the servo control. This is accomplished by a servo motor positioning control device comprising means for outputting to an amplifier.

[Effect]

In the above servo motor positioning control device, when a desired deceleration curve is given as a time function of position deviation, the time variable is eliminated from the speed time function obtained by differentiating this curve and the position deviation time function. Find the relational expression between positional deviation and speed, calculate the speed command value that is 'OE' in the above relational expression according to the detection result of the positional deviation of the servo motor, and set the gain sufficiently high to reduce the delay in quick response. By controlling the speed of the servo motor by outputting K from the servo amplifier (speed amplifier), a predetermined deceleration curve can be realized, and positioning control with a desired response speed and low residual vibration can be achieved.

〔Example〕

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

FIG. 1 is a block diagram showing an embodiment of a servo motor positioning control device according to the present invention. In Figure 1, %
1 company servo motor, 2 is speed detector, 5 is pulse encoder, 4 is counter, 5 is servo amplifier (speed amplifier)
, 6 is a Q/A converter.

7 is a control device. The rotational speed of the servo motor 10 in the same figure is detected by the speed detector 2, the rotation angle of the servo motor 10 is detected by the pulse encoder 3 and the counter 4, and a detection signal of the rotation angle is sent to the control device 7. The speed command output from the control device 7 is converted into an analog voltage by the I/A converter 6, and the difference between the output and the detection output of the speed detector 2 is converted to a servo amplifier (speed amplifier) 5. After amplification, a mark is placed on the servo motor 1 to control the speed of the servo motor. If this velocity feedback gain is sufficiently high, the servo motor 1 will respond to the output of the line converter 6 without delay.

In the control device 1, the positioning target value θ and the counter 5
The position deviation △0 from the detected rotation angle 0 of the output is Δe =
e, -# (1) Calculate K.

Now, the deceleration curve is expressed as a function of time, Δe = r (t) (2)
By differentiating this.

becomes. If we eliminate time t from equations (2) and (3), we get
= 2(Δθ) (4) The relational expression between the deviation Δ0 and the speed δ is found. Therefore, the control device 7 calculates the value of the speed according to the deviation Δθ of the equation (1) from the equation (4), and outputs this as the speed command value to the line converter 6, thereby giving the value given by the equation (2). Slow down! f
(t). Incidentally, the smaller value of equation (4) is actually output as the speed command value for the servo motor. Also, if necessary, define the acceleration curve in the same way as a function of the amount of movement θ2 from the start of movement, and δ = h (θ) (5) is better.In this case, -, Equation (4) Equation (5)
+7) The minimum value among the values (7) may be output as the speed command value.

This control device 7 has a function of determining the relational expression of Equation (4) according to the deceleration curve given by Equation (2), or stores a plurality of functions of Equation (4) determined in advance. If there is a function to select by designation or a function to store the separately calculated equation (4) as an equation or a table, it becomes possible to control the positioning of the servo motor according to various deceleration curves.

Next, the deceleration curve is △θ=a(t,-t)' a, t: constant Consider the case given by . At this time.

θ=-Δθ=-ma(t,-t)ll-1 and nasi, 5 1=-,62)u (Δθ) ma” l ΔD l
”.Here, when m = 2, % When m = ω, n = 1, and the conventional proportional control corresponds to m = ψ, and the 1/2 power proportional control corresponds to the deceleration curve of m = 2. However, in m-2, as the deviation becomes smaller, the speed becomes extremely low and positioning takes time, and in m:2, the jerk becomes infinite when stopped and residual vibration remains. If the jerk is constant, - Δθ = c, o: constant dt', and the deceleration curve is m-3.If the
If it is set to 4, the jerk at stop will be zero and the residual vibration will be low. Also, various cam curves have been proposed as ones with less residual vibration, and the control of this method can realize such response.

〔Effect of the invention〕

According to the present invention, a response having an arbitrary deceleration curve can be realized in positioning control of a servo motor, so that it is possible to obtain a desired response speed and a response with low residual vibration.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a servo motor positioning control device according to the present invention. 1... Servo motor, 2... Speed detector. 3...Pulse encoder, 4...Counter, 5...
- Servo amplifier, 6...D/A converter, 7...control device.

Claims (1)

[Scope of Claims] 1. Means for determining a speed command value as a nonlinear function with respect to positional deviation in order to obtain a required deceleration curve of positional deviation with respect to time; and means for determining a speed command value from the nonlinear function according to a detection signal of positional deviation. A servo motor positioning control device comprising means for driving and positioning a servo motor by determining and outputting it to a servo amplifier. 2. The servo motor positioning control device according to claim 1, which has a function of automatically determining or selecting a nonlinear function according to the specified deceleration curve. 3. As the above nonlinear function, v=-Agn(Δx)k|Δx|＾n v: Speed command value Δx: Position deviation k: Constant n: Give a constant of 0.5≦n≦1 and specify the constant n. Therefore, 1/(
2. The servo motor positioning control device according to claim 1, wherein a deceleration curve of the 1-n) power is obtained. 4. The servo motor positioning control device according to claim 1, wherein values of speed command values for positional deviations are set as a table in accordance with the specified deceleration curve.