JPH07225615A - Full closed loop position control servo driver - Google Patents

Abstract

PURPOSE:To speed up full closed position control by the full closed position control servo driver and simplify a controller. CONSTITUTION:A position loop is formed by feeding the full closed position signal from a position detector on the side of a load such as a linear scale 11 back to the deviation counter of the driver 15. Speed feedback is provided to the driver 15 by using a rotary encoder 9 fitted to a motor 8 as a detector to form a speed loop. While a conventional position control driver uses the position feedback signal of the rotary encoder fitted to the motor as a speed feedback signal in common, this full closed position control driver 15 requires both the signals individually and has input parts corresponding to both the signals. The full closed loop position control is performed only by the driver 15 and semiclosed loop control is not performed at the time of signal processing, so the full closed loop control is speeded up and controller software and hardware are simplified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor drive control driver (hereinafter abbreviated as driver) for performing positioning control, which is capable of detecting a signal from a position detector on the load side and performing full closed loop control. The present invention relates to a closed loop position control servo driver.

[0002]

2. Description of the Related Art In recent years, position control servo drivers / motors have been used in component mounting machines, robots, semiconductor manufacturing equipment, F
It is used in various fields in the field A for position control by a motor.

To perform load positioning control by a motor, a stepping motor (also referred to as a pulse motor) or a servo motor in which a position detector is attached to a synchronous motor or an induction motor is used by a driver according to a command from a controller. A drive control method is generally used.

When position control is performed by a motor, a forward / reverse rotation position command pulse is input to the driver from the controller, the driver amplifies the current, and the motor is driven by an angle corresponding to the command pulse.

An example of the conventional position control by the above-mentioned motor will be described below with reference to the drawings.

FIG. 2 shows an example in which position control is performed by a stepping motor. In FIG. 2, reference numeral 1 is a controller that outputs a command pulse. 2 is a stepping driver,
Reference numeral 3 is a stepping motor, 4 is a table to be subjected to position control, 5 is a ball screw, and 6 is a forward / reverse position command pulse.

Since the stepping motor is a position control motor which is originally driven by a pulse, it can be controlled by an open loop which does not require position detection by a position detector.

FIG. 3 shows an example in which position control is performed by a servo motor. In FIG. 3, reference numeral 1 is a controller that outputs a command pulse. 4 is a table to be position controlled, 5 is a ball screw, 6 is a forward / reverse position command pulse, 7 is a position control servo driver, 8 is a servo motor,
Reference numeral 9 is a rotary encoder, and 10 is a semi-closed position feedback signal.

In order to perform position control by the servo motor, it is necessary to perform closed loop control in which the position detection signal from the position detector is fed back to the driver. A rotary encoder is used as the position detector and is generally mounted on the opposite side of the motor shaft.

The position resolution of the stepping motor cannot be expected to be high because it is limited by the magnetization of the motor. However, the position resolution of the servo motor depends on the resolution of the rotary encoder, and is therefore higher than that of the stepping motor.

Therefore, a servo motor is used for high-precision positioning control of several tens of μ or less.

However, in the position detection by the rotary encoder attached to this motor, strictly speaking, the final position control of the load is not performed due to the influence of mechanical errors on the load side. Therefore, although this control is closed loop control, it is called semi-closed loop control.

When performing high-accuracy positioning control of several μ or less, it is impossible to realize high-accuracy positioning not only due to backlash of the machine but also due to elongation of the ball screw due to temperature rise due to friction. It is difficult, and in this case, full-closed loop control is required in which a position detector is attached to the load subject to final positioning control and position control is performed. A linear scale or a laser scale is generally used for this position detector.

FIG. 4 shows an example in which full-closed loop position control is performed by a servo motor. 1 in FIG.
Outputs a command pulse with the controller and performs correction control. 4 is a table to be position controlled, 5 is a ball screw, 6 is a position command pulse for forward / reverse rotation, 7 is a position control servo driver, 8 is a servo motor, 9 is a rotary encoder, 10 is a semi-closed position feedback signal, 11 is a linear scale attached to the table,
Reference numeral 12 is a full-closed position feedback signal, and 13 is a positioning completion signal.

[0015]

When performing full-closed loop position control, a position counter is provided in the controller and the position control motor is first driven by inputting a pulse command corresponding to the target movement amount to the driver. . After the positioning is completed, the controller reads the position information of the position detector attached to the load to be subjected to the final positioning control, and inputs the correction pulse for the error with respect to the target position to the driver again. By repeating this control, high-precision positioning control of the load is realized.

However, this correction requires a considerably long time, making it difficult to increase the speed, and the software / hardware of the controller is complicated.

[0017]

In view of the above problems, the present invention focuses on having a position control loop at the time of semi-closed loop control by a servomotor, and the format of output signals of commercially available linear scales and laser scales. Is used as the output signal of the rotary encoder attached to the motor, realizing full-closed loop position control without the need for correction work in the controller, providing faster positioning and simplification of the controller. It is a thing.

[0018]

In the semi-closed loop control of the servo motor, the driver is provided with a deviation counter and the counter value is controlled to 0 to perform the positioning control. The command in this case is a forward / reverse position pulse command from the controller, and the feedback is a detection pulse signal of the rotary encoder of the motor.

Here, by making the feedback signal a detection pulse signal of the position detector attached to the load, it becomes possible to realize the fully closed position control only by the driver without the need for correction control by the controller. .

Further, in the correction control by the controller, the command pulse amount for the correction is only a few pulses and it is difficult to output the torque of the motor. Therefore, in addition to the correction control time of the controller, a longer time is required for positioning. In the present invention, since there is no correction time by the controller and a small pulse command such as a correction pulse is also eliminated, it is possible to realize the positioning time by full closed loop control as fast as a semi-closed loop.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In FIG. 1, reference numeral 1 is a controller that outputs a command pulse. 4 is a table to be position controlled, 5 is a ball screw, 6 is a position command pulse for forward / reverse rotation, 8 is a servo motor, 9 is a rotary encoder, 11 is a linear scale attached to the table, and 12 is a fully closed position. A feedback signal, 13 is a positioning completion signal, 14 is a velocity feedback signal, and 15 is a fully closed position control servo driver.

Position detection is mounted on the table 11
Position detector to output a pulse signal with a two-phase 90 ° phase difference. Since a speed loop is necessary for position control of the servo motor, a speed detector 9 is required. The speed detector is a rotary encoder or tacho-generator attached to the motor. 2 for rotary encoders
A pulse signal with a 90 ° phase difference is output. In the case of a tacho generator, the output will be an analog voltage. When viewed from the controller of No. 1, in the present invention, it can be controlled by an open loop,
It only outputs the forward / reverse position pulse command. 15
The input signal of the full-closed loop position control servo driver is required to have 6 command pulses, 12 full-closed position feedback signals, and 14 velocity feedback signals. In the conventional driver for semi-closed loop positioning control, since the position detection pulse signal of the rotary encoder is also used as the speed detection signal, there are no 14 speed feedback signal input sections.

Operationally, it is no different from a semi-closed loop servo motor. When the command pulse is input from the controller to the deviation counter in the driver, the driver performs current amplification to generate the torque necessary to drive the table load, and rotates the motor for the command pulse to move the load (table). When the table load moves, position detection feedback pulses from 11 position detectors mounted on the table are input to a deviation counter in the driver. The driver of 15 controls the counter value to 0 to complete the positioning control in the fully closed loop. When the positioning is completed, the 15 driver outputs the 13 positioning completion signal to the controller,
The controller determines the positioning completion.

[0025]

As described above, the present invention enables full-closed loop position control only by the servo driver.
In addition, positioning is possible at a higher speed than the conventional controller-based correction method. Further, since the controller performs open loop control, simplification of both software and hardware of the controller can be realized.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram of an example in which position control is performed by a conventional stepping motor.

FIG. 3 is an explanatory diagram of an example in which position control is performed by a conventional servo motor.

FIG. 4 is an explanatory diagram of an example of a case where full-closed loop position control is performed by a conventional servo motor.

[Explanation of symbols]

 1 Controller 2 Stepping Driver 3 Stepping Motor 4 Table 5 Ball Screw 6 Forward / Reverse Position Command Pulse 7 Position Control Servo Driver 8 Servo Motor 9 Rotary Encoder 10 Semi-closed Position Feedback Signal 11 Linear Scale 12 Full-closed Position Feedback Signal 13 Positioning Completion Signal 14 Speed feedback signal 15 Fully closed position control servo driver

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Claims (1)

[Claims] 1. A servo motor including at least a rotary encoder, a position control driver for controlling the servo motor, a full-closed loop position control servo driver including a controller and a linear scale, and a position detection signal from the linear scale and a rotary. A full-closed loop position control servo driver, characterized in that the speed detection signal from the encoder is fed back to the position control driver to perform positioning control, and after the positioning is completed, the position control driver outputs a positioning completion signal to the controller.