JPH0332383A - Check system for servo system - Google Patents

Abstract

PURPOSE:To alleviate a load of a CPU calculation and to facilitate confirmation of operation of a servo motor by approximating current loop characteristic based on a servo motor by a simple function. CONSTITUTION:An approximate calculator 21 corresponding to a current loop from an input unit of a current command i* to an output unit of a current (i) is provided. A position regulator 1, a speed regulator 2 and a position detec tor having a torque constant Kt 12, a term 13 by an inertial J, an integrating term 15 are provided. A software program approximated to the characteristic of a current loop composed of them is provided, a simulation software program easy of a CPU calculation is calculated by a CPU of existing controller by using the software program, and checked by the result of the simulation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a checker system using simulation calculations for a servo system using, for example, a servo motor.

[Prior Art] FIG. 3 is a block diagram showing an example of the configuration of a conventional digital servo system. In the figure, (5) is the main circuit of the servo amplifier, and the diode (
5I), smoothing capacitor (52), transistor (53
) and a current detector (54). <6
〉 is a servo motor section, which is composed of a motor body (61) and a speed and position detector (62〉).(30
) is a digital control circuit for the servo amplifier (5), and the internal CPU (31) is connected to various memory devices 34) by a husk 33), and also connected to the digital control circuit (30) by an interface circuit (35a). The interface circuit (35b) is connected to the second controller (60) that controls the servo system at the higher level, and the display device (32) that monitors the operating status of the servo system is connected to the analog monitor device (60) that is controlled by the D/A converter (39). It is connected to the.

Furthermore, the detected values of the position and speed of the servo motor (61) are given to the hash (33) by the counter (36), and the output current value of the servo amplifier (5) is given to the lotus (33) by the A/D converter 37). An operation signal is transmitted to the amplifier (5) by a PWM circuit (38).

FIG. 4 is a block diagram showing the configuration of a control loop of a servo system using a DC servo motor. ■
and τ are motor position, speed, current, voltage and l・
θ, ω**1*v* indicate each command value. In the figure, (1
) is a position regulator, (2) is a speed regulator, and (3) is a current regulator, all of which are processed by a CPU (3) that executes control program software.

G (S) is each transfer function. (5) is a servo amplifier with a gain of 1, (11) is a resistance R, a time constant T and a
a The electrical characteristics of the motor, ri12) are the torque constant Kt(13
) is a term due to inertia J, (14) is a voltage feedback term with gain Kv, and (15) is a position detection section having an integral term.

The performance and mechanical characteristics of the control operations of the servo system as described above can be checked by monitoring various operating data while the actual machine is in operation, or by separating drive system hardware such as motors and detectors. A method may be used in which the characteristics of the drive system are replaced with a simulation program, and this and the control program are executed in the same system to simulate the operation of the Zaho system and the results are obtained in advance.

For example, in Fig. 4, if we focus on the current loop from the human power part of current command l* to the output part of current 1 and rewrite it, we obtain Fig. 5(a), which is further transformed into Fig. 5(b). It can also be rewritten as Is it possible to perform simulation calculations using a software program for the transfer function of this current loop?However, this transfer function includes a lead term and a quadratic lag term, and the CPU calculation requires considerable processing time. In order to perform this calculation, a method is proposed in which a separate CPU device is provided for this calculation.

FIG. 6 is a block diagram showing an example of an apparatus for performing this simulation disclosed in Japanese Patent Application Laid-Open No. 58-222357. Transfer (7) to the device shown in Figure 3 (=1
With the added simulation processing circuit, CPU (7
1), a memory (72), etc., and a bus <73
> is connected to the bus (33) of the digital control circuit (30). When performing a simulation, a simulation processing circuit (7) is connected to the control loop in place of the drive system, a simulation of the control operation is executed, and the results are checked on a monitor.

[Problems to be Solved by the Invention] In the servo system configured as described above, it is not practical to check the operation of the system including the host controller while the control circuit and motor section are connected. It is difficult to do this satisfactorily due to the following restrictions.

Also, when installing the motor on the machine after the check is completed, there are problems such as shortening the construction period or not being able to do so.

In order to avoid this problem, if a method is used in which the driving operation is checked by performing calculations using a drive system simulation program without connecting the motor, a separate CPU and other peripheral devices are required for the simulation program calculations. The problem was that it was expensive.

This invention was made to solve the above-mentioned problems, and it is possible to easily check the operation of a servo motor without using a servo motor or a detector, and without requiring a separate CPU device. This provides a check method that allows for

[Means for Solving the Problems] The servo system check method according to the present invention provides a software program that approximates the characteristics of a current loop consisting of a servo motor and a detector for its output, etc., and uses this software program to check the servo system. A simulation software program that can be easily operated by the CPU is operated by the CPU of an existing control circuit, and the simulation results are used for checking.

[Embodiment] FIG. 1 is a block diagram of a simulation control loop composed of software in a servo system check method according to an embodiment of the present invention. In the figure, (
1), (2), (12), (1g),
(1, 5) are the same parts as the parts with the same symbols in FIG. 4 showing the conventional example. (21) is an approximate calculation unit corresponding to the current loop from the input part of the current command l* to the output part of the current i in FIG. This current loop is originally expressed as shown in FIG. 5 (1), but in the present invention, it is expressed as a transfer function G (S) that approximates this as e ] T1. T2 uses a current time constant.

Software program calculation for current loop simulation using this approximate formula is relatively easy, and the load on the CPU that executes it is light, so it is possible to use the existing CPU (31,) and peripheral devices in the control circuit (30). It is possible to perform a simulation calculation according to FIG. 1 to check the operational function.

Further, since the current loop section using such an approximation formula is a minor loop, the approximation has little influence on the response of variables used as operation check items, such as motor position θ and speed ω.

During normal operation of the servo system in this embodiment, calculations are performed up to the step of outputting the voltage V to the servo motor section (6) based on the command θ* from the control circuit (30) or the host controller (60). By switching this with a switch or changing a parameter, the control loop filtering shown in Fig. 1 is executed by the software program in the above control circuit (30), and the control loop filtering shown in Fig. In the disconnected state, the motor position θ, speed ω, current l, and other system operations are checked. Figure 2 is a front view of the display unit (2) that monitors these values.
A display example of 0 rpm is shown.

In the above embodiment, the case where a DC servomotor is used has been described, but even in the case of an AC servomotor, the same method as in the above embodiment can be used.

[Effects of the Invention] As explained above, the present invention reduces the load on CPU calculations by approximating the current loop characteristics mainly in the servo motor section with a simple function, and requires a separate CPU device etc. during simulation calculations. Even if installation is required, it is possible to use the CPU of the existing control circuit in the servo system to execute it, which is effective in reducing costs and facilitating system checks.

[Brief explanation of drawings]

Fig. 1 is a block diagram of simulation control for executing a servo system check method according to an embodiment of the present invention, Fig. 2 is a front view of a display, and Fig. 3 shows an example of the configuration of a normal servo system. Block diagram, Figure 4 is a block diagram of simulation control for executing the conventional servo system check method, Figure 5 (a) = (
b) is a block diagram of the current loop in FIG. 4, and FIG. 6 is a block diagram showing an example in which a CPU is separately added to the servo system of FIG. 3. In the figure, (6) is the motor section, (21) is the current loop approximation calculation section, (30) is the control circuit, (31) is the CPU,
(32) is a display, and (61) is a motor body. iS
The same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] A digital control circuit equipped with a CPU and its peripheral equipment, a servo motor driven by the digital control circuit, and a detection means for displaying the position, speed, etc. of the servo motor in its operating state. In the servo system, a software program is provided that approximates the characteristics of the current loop mainly consisting of the servo motor section, the servo motor and the detection means are separated from the control loop, and the servo motor and the detection means are replaced with this, and the simulation is performed using the software program. A servo system check method characterized by executing calculations.