JPH01190280A - Motor controller - Google Patents

Abstract

PURPOSE:To follow up with high quick response, by increasing or reducing motor driving current in accordance with the working pattern of a load. CONSTITUTION:To the rotary shaft of a motor 1, a rotary encoder 2 is bonded, and the pulse signal of frequency in accordance with motor rotational-frequency is counted by a counter 3. The input of the signal to a processor 4 is provided, and by the algorithm of a ROM 6, the actual rotational frequency of the motor 1 and the set rotational frequency of a working directing section 5 are compared with each other, and arithmetic is performed on the rotational frequency and current value of current applied to the motor 1. Besides, a current command value on which arithmetic is performed is compared with motor actual-current with motor current read by a current detector 7 via an A/D converter 8, and the current command value is corrected so that its deviation may come to zero. The input of the corrected current command value to a PWM signal generator 9 is provided, and the output of motor driving current in accordance with the duty of specified pulse signal is generated. Then, the input of the varying pattern of load torque to the processor 4 from the working command section 5 is provided, and a set value is changed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a motor control device for controlling the motor speed of industrial robots, VTRs, and the like.

[Conventional technology]

Conventionally, in devices such as industrial robots and VTRs that use the rotational force of a motor (DC motor or AC motor) as a driving power source, in order to make the motor rotation speed match the set rotation speed, the actual rotation speed of the motor is A control system that detects the rotation speed with a rotation speed detector such as a 0-tari encoder, compares the detected rotation speed with the set rotation speed, and performs feedback control of the frequency and current value of the motor applied current so that the deviation becomes zero. It is equipped with

However, with only a feedback control system for controlling the rotation speed, the motor current fluctuates depending on the size of the load, so it is necessary to develop a control system that also detects the motor current value itself and performs feedback control to maintain an appropriate current value. There is something added as a minor loop.

[Problem to be solved by the invention]

However, even in the case where a control system for motor If flow control is added, it only absorbs changes in the motor current according to load fluctuations, that is, it is possible to adjust the excess or deficiency of the motor current caused by load fluctuations over time. Since the correction is only made after a delay, the problem is that when the load starts to change significantly, for example when the robot starts lifting the workpiece, the required motor current becomes too much or too little, causing a delay in the movement of the workpiece. was there.

An object of the present invention is to provide a motor control device that can follow a load with high adaptability.

[Means to solve the problem]

The present invention achieves the above object by adding a control means that generates a command to increase or decrease the motor drive current in accordance with a required change pattern of load torque.

[Effect]

For example, in a robot, when lifting a workpiece, the load torque is large and the motor current is also large; in the opposite case, the load torque is small and the motor current is also small. Such a change in load torque is uniquely determined by the movement pattern of the robot. Therefore, when looking at the motor that moves the workpiece, in response to changes in the movement pattern of the workpiece, an increase command is issued to increase the motor current when lifting the workpiece, and a decrease command is issued to decrease the motor current in the opposite case. to correct the motor current. This allows the load such as the workpiece to follow the predetermined movement pattern with high adaptability.

【Example〕

FIG. 1 is a block diagram showing an embodiment of the present invention, in which a rotary encoder 2 for detecting the rotational speed of a motor 1 is coupled to a rotating shaft of a motor 1. As shown in FIG.

A pulse signal having a frequency corresponding to the motor rotation speed output from the rotary encoder 2 is counted by a counter 3. As a result, the counter 3 outputs a rotation speed detection signal representing the actual rotation speed of the motor 1. This rotation speed detection signal is input to the processor 4. The processor 4 compares the actual rotation speed of the motor 1 with the set rotation speed input from the operation instruction unit 5 (for example, a host computer such as a robot controller) according to an algorithm stored in a read-only memory (ROM) 6. The frequency and current value of the current applied to the motor are calculated so that the deviation becomes zero. Furthermore, the current command value that has been performed is detected by current detection! The motor mR value detected by g7 (for example, a Hall element or a shunt resistor) is compared with the actual motor current read through the AD converter 8, and the current command value is corrected so that the deviation becomes zero ( Incoming current (minor loop).

The corrected current command value is input to the PWM signal generator 9. The PWM signal generator 9 generates a pulse signal with a duty ratio corresponding to the input current command value, and increases #A.
L! ! ! Enter 10. The motor 1 of the width width device 10 is
When configured with a C motor, it is configured with an inverter device, which outputs a motor drive 111N flow corresponding to the duty ratio of the pulse signal input from the pulse generator 9 and inputs it to the motor 1. As a result, motor 1
The rotation speed changes in accordance with the load operation pattern input from the operation instruction section.

Here, in the present invention, the change pattern of the load torque is further inputted from the operation instruction section 5 to the processor 4, and the set value of the current command value is changed accordingly. That is, when the load is large (when large torque is required), the current value is increased in advance.

For example, if the load torque required to operate the load changes over time as shown in FIG. 2, the motor drive current vJ changes as shown in FIG. 3 according to the change in load torque. The current command value is increased or decreased so as to change with continuous temporal changes, and this current command value reduced by yt1 is input to the PWM Buddha Pi generator 9.

As a result, when a large load torque is required, the current command value is increased in advance, so that the load can quickly follow the required speed.

In this way, by adding a control system that increases or decreases the motor drive current in accordance with the operating pattern of the load, it is possible to follow the load with great adaptability.

Note that although the rotational speed of the motor 1 is detected by the rotary encoder 2 and the counter 3, it can be easily replaced with a known rotational speed detector such as a tachogenerator.

Moreover, it can be applied not only to industrial robots but also to motor control of VTRs and the like.

[Effects of the Invention] As described above, according to the present invention, since the motor drive current is increased or decreased in accordance with the operation pattern of the load, it is possible to follow the load with high degree of coordination.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram showing an example of a temporal change in load torque, and FIG. 3 is an explanatory diagram showing an example of a temporal change in motor drive current. It is. 1...Motor, 2...Rotary encoder, 3...
- Counter, 4... Processor, 5... Operation instruction unit, 6... Read-only memory, 7... Current detector, 8
...AD converter, 9...PWM signal generator, 10.
··amplifier. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] A rotation speed detection means for detecting the rotation speed of the motor, a current detection means for detecting the drive current of the motor, and a drive current for the motor having a frequency and a current value corresponding to the set rotation speed. A motor control device comprising a control means for performing feedback control, characterized in that a current control means for generating an increase/decrease command for motor drive current in response to a required change pattern of load torque is provided in the control means. Motor control device.