JP3435828B2 - Automatic lead angle determination method for phase controlled servo system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an advance angle control for correcting a phase delay of an electronic cam application machine applied to a phase control of a transfer robot or other simple robots. And a method for automatically determining the advance correction amount. 2. Description of the Related Art FIG. 6 is a block diagram of a conventional servo system for performing phase control. In the figure, 1 is a controller,
2 is a servo driver, 3 is a servo motor, 4 is a pulse generator, 11 is a phase command, 12 is a position pattern generating circuit for generating a position command having a position pattern uniquely associated with the phase command 11, 21 is a position command, 22 is a feed forward speed command, 23 is a position control gain, 24 is a DA converter, 25 is a counter, 26
Is position feedback, 30 and 31 are DA converters, 51
Is a pen recorder. As shown in FIG.
When phase control is performed by giving a position command 21 generated by the position pattern generation circuit 12 to the position loop for 1 and after strictly adjusting the speed control gain, the position control gain 23, and the feedforward speed command 22 of the servo driver 2 However, a position error finally occurs due to an output delay of the D / A converter 24, an input delay of the servo system, and a response delay. As a means for solving this, as shown in FIG.
(Hereinafter referred to as advance angle control). In the figure, 13 is a differentiating circuit, 14 is a phase advance circuit, 12 is a position pattern generating circuit that has advanced the phase, and 15 is a switch that closes when performing advance angle compensation. Here, the phase advance circuit 14 receives an advance amount Δ with respect to the input of the phase transition speed ω.
a function generator for outputting a theta, relationship ω and Δθ is proportional with the constant slope (proportional constant a), as shown in FIG. Conventionally, the position command 21 is used to determine the advance amount.
The position feedback 26 is output via the D / A converter 24 and is drawn on the pen recorder 51 or the like to measure Δθ in a diagrammatic manner as shown in FIG. Also, this amount Δ
Since θ is almost proportional to the phase transition speed ω, as shown in FIG.
The proportionality constant a was determined by the equation θ = a · ω, and was incorporated as the phase advance circuit 14. The ω obtained in this way
6 is set in the phase advance circuit 14 in FIG. 6 and the advance amount correction is performed by adding the advance amount Δθ obtained according to the input ω to the phase command 11, so that the controller and the servo circuit itself are used. Can be compensated for. However, in such a conventional technique, in order to obtain the slope (proportional constant) a, the output D of the position command 21 and the position feedback 26 is required.
A / A converter 24 is required, and a pen recorder 51 is provided externally.
Required. In addition, it requires time and effort to obtain a gradient (proportional constant) a in a drawing using a diagram drawn on the pen recorder 51 or the like, and no accuracy is obtained. Therefore, the present invention provides a method for automatically determining a lead angle correction amount for automatically correcting a phase delay of an electronic cam applied machine without using a pen recorder. [0004] In order to solve the above-mentioned problems, the present invention provides a phase command corrected by a phase advance circuit.
θ, the position pattern generation circuit is
Generate a position command according to the position pattern, and
Of the controller that controls the servomotor according to
In the phase control method, the controller
When the command of the fixed command button is received, the lead angle constant a is calculated and
Equipped with a lead angle proportional constant calculation means that outputs to the phase advance circuit
Characterized by the following steps:
A method for automatically determining the advance angle of the servo system to be controlled. (1) Lead angle complement
The switch that closes when the compensation is made is opened.
(2) The speed of the servo driver that drives the servo motor
Degree control gain and position control gain, feed forward speed
After adjusting the degree command, perform phase control operation. (3)
The advance angle determination command when the servo motor is at a constant speed.
The scan time t1 immediately after the trigger by pressing the button
The position command A of the controller and the position feedback
The memory B is stored. (4) Position feed after n scans
The back C is stored. (5) Proportional constant a = (AB) /
An operation of (CB) × n · Ts / 1000 is performed. (6)
The proportionality constant a is output to the phase advance circuit. According to the above means, the advance correction amount can be automatically determined without using a recording device such as a pen colletor and without performing an artificial drawing operation. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of the present invention. The configuration of only the portions different from FIG. 6 will be described. Reference numeral 16 denotes an advance angle determination command button, and 17 denotes an advance angle amount proportional constant calculation circuit that receives the signal and calculates a proportional constant a for determining the advance amount. . FIG. 2 is a diagram for explaining the principle of the present invention. The horizontal axis represents time t, and the vertical axis represents position x. A position command at a constant speed (for example, speed = ω in FIG. 4) and a servo axis following the position command are shown. Represents the change in the position feedback. Ts (m
s) represents the scan time of the controller, and it is assumed that the scan time of the controller of the present invention is a fixed time Ts (ms). First, the switch 15 is opened to adjust the speed control gain, the position control gain 23, and the feedforward speed command 22 of the servo driver 2, and then the phase control operation is performed. When the servo motor 3 is at a constant speed, the position command and the position feedback are in parallel as shown in FIG. At this time, a trigger such as the advance angle determination command 16 causes a scan time t1 immediately thereafter.
, The position command 21 and the position feedback 26 inside the controller 1 are stored. The values are A,
B (FIG. 2). Then, at time t3 after n scans, the position feedback signal is read and stored again, and then the following arithmetic processing is performed. From FIG. 2, the delay time td (ms) of the position feedback with respect to the position command is td = ( AB ) / ( CB ) × n · Ts. When this is converted into the amount of phase (°), Δθ (°) = ω × td / 1000 = ω × ( AB ) / ( CB ) × n · Ts / 1000 Δθ = a · ω The coefficient a is as follows: a = (AB) / ( CB ) × n · Ts / 1000 The lead angle proportional constant calculating means 17 in FIG. 1 calculates the proportional constant using the above principle, and FIG. 3 shows the processing procedure. The proportional constant a obtained by this operation is set in the phase advance circuit 14 of FIG. Switch 1
5, the phase command 11 is added by the advance angle amount Δθ, and the position command 21 is given. Once determined, this value can be used thereafter without changing the mechanical structure, the gain of the control system, and the like. As described above, the present invention does not require any device such as a D / A converter and a pen colletor in advance angle control as a means for correcting a phase delay in a servo phase control system. It is possible to automatically determine a highly accurate advance angle correction amount without requiring any manual drawing work.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing an embodiment of the present invention. FIG. 2 illustrates the principle of the present invention. FIG. 3 is a diagram showing a procedure for determining an advance angle amount. FIG. 4 is a diagram illustrating a phase shift and a speed of a position command and a position feedback. FIG. 5 is a diagram showing a phase advance amount with respect to a phase velocity. FIG. 6 is a diagram showing a method for measuring a phase shift between a position command and a position feedback according to the related art. [Description of Signs] 1 Controller 2 Servo driver 3 Servo motor 4 Pulse generator 11 Phase command 12 Position pattern generation circuit 13 Differentiation circuit 14 Phase advance circuit 21 Position command 22 Feed forward speed command 23 Position control gain 24 DA converter 25 Counter 26 Position feedback 51 Pen recorder etc. 61 Lead angle decision signal push button

Claims (1)

(57) [Claims 1] The phase command θ corrected by the phase advance circuit
When the position pattern generation circuit receives the
A position command is generated according to the position pattern, and
Therefore, the electronic cam of the controller that controls the servomotor
In the phase control method, when the controller receives a command of the advance angle determination command button,
Calculates the lead angle constant a and outputs it to the phase advance circuit
A lead angle constant calculation means is provided, and is processed in the following procedure.
Advance of a phase controlled servo system characterized by controlling
Automatic decision method. (1) The switch that closes when performing lead angle compensation is open
To (2) The speed of the servo driver that drives the servo motor
Degree control gain and position control gain, feed forward speed
After adjusting the degree command, perform phase control operation. (3) When the servo motor is at a constant speed,
Scan immediately after the triggering by and pressing the advance decision instruction button
Said controller position command A and position in down time t1
The position feedback B is stored. (4) Store position feedback C after n scans
You. (5) Proportional constant a = (AB) / (CB) × n · Ts
/ 1000 is calculated . (6) The proportionality constant a is output to the phase advance circuit.