JPH0677222B2 - Positioning control device - Google Patents

Description

The present invention relates to a positioning control device for machine tools and the like, and more particularly to a positioning control device with improved positioning response accuracy.

[Conventional technology]

A conventional device of this type is shown in FIG. FIG. 3 shows an overall circuit block diagram of a conventional device. In FIG. 3, (1) is a position command circuit for inputting a command of a moving position of a machine (8), and (2) is a position of the position command circuit (1). A position deviation calculating circuit that detects command data and position feedback data and outputs a position deviation, (3) a speed amplifier that outputs electric power corresponding to the position deviation output by the position deviation calculating circuit (2), ( 4) is a motor driven by the electric power output from the speed amplifier (3), (5a) is a speed detector of the motor (4), (5b) is detected by the speed detector (5a) The speed value thus obtained is compared with the position deviation of the position deviation calculation circuit (2) and output to the speed amplifier (3), and a comparator constituting a feedback circuit (6) is rotated by the motor (4). A gear that causes the machine (8) to move, and (7) rotates the gear (6). A ball screw (8) is the control object machine to move the machine (8) is converted into a linear movement,
(9) is a position detector that detects the amount of movement of the machine (8) and returns it to the position deviation calculation circuit (2).

Next, the operation of the conventional device based on the above configuration will be described with reference to FIG. FIG. 4 shows a waveform diagram of the control pulse. First, when the operation command pulse corresponding to the movement of the machine (8) to the target position is given from the position command circuit (1),
The position deviation calculation circuit (2) compares the current position data of the machine (8) detected by the position detector (9) and outputs the position deviation until the deviation becomes "0" (reaching the target position). to continue.

Further, the speed amplifier (3) rotates the motor (4) at a speed corresponding to the position deviation, and moves the machine (8) to the target position via the rotary gear (6) and the ball screw (7). The position of the machine (8) is detected by the position detector (9), and the detected value is fed back to the position deviation calculation circuit (2),
The operation is completed by detecting the arrival at the target position.

[Problems to be solved by the invention]

Since the conventional positioning control device is configured as described above, a dead zone element such as backlash is included in the mechanical system of the control loop. Therefore, if the response characteristics of the position control loop and the speed control loop are improved, The limit cycle phenomenon that the motor moves back and forth will occur in the backlash of the system, the final machine position will not remain stationary, the fluctuation will continue, and the response characteristics of the position control loop and speed control loop can be improved. It had a problem that it could not be done.

The present invention has been made to solve the above problems, and to obtain a positioning control device capable of quickly fixing the final machine position and improving the response characteristics of the position control loop and the speed control loop. With the goal.

[Means for solving problems]

The positioning control device according to the present invention is inputted with position command data for instructing a moving position of a machine and current position data representing a current position of the machine, calculates a deviation of each of the above data, and rotates normally according to its polarity. Position deviation calculating means for outputting a position signal of a pulse number or a reverse rotation pulse in proportion to the deviation, a polarity holding means for holding the polarity of the calculation result of the position deviation calculating means, and the position deviation calculating means. From the deviation pulse and the polarity from the polarity holding means are input, and a dead band is formed by canceling the first pulse of the deviation pulse and outputting a control signal formed by the remaining pulses on condition that the polarity is inverted. Means for controlling the moving position of the machine based on a control signal from the means and the dead zone forming means.

[Action]

In the positioning control device according to the present invention, when the polarity of the calculation result of the position deviation calculation means is reversed, the first pulse of the reversed deviation pulse is canceled and the dead zone forming means sends out a control signal with a reduced number of pulses. The machine is positioned by this control signal.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 shows an overall circuit block diagram of this embodiment, and FIG. 2 shows a control pulse output waveform diagram. The positioning control device according to this embodiment includes a position command circuit (1) and a position deviation calculation circuit of the conventional device. (2), speed amplifier (3),
In addition to the motor (4), speed detector (5a), comparator (5b), gear (6), ball screw (7), machine (8) and position detector (9), the position deviation calculation circuit (2) A polarity holding circuit (10) for holding the polarity of the deviation output, and the polarity of the polarity holding circuit (10) and the deviation output of the position deviation calculation circuit (2) are input, and the polarity is inverted A dead band circuit (11) for canceling the first pulse in the deviation pulse of the deviation output to form a control signal, and driving the motor (4) based on the control signal of the dead band circuit (11) to drive the machine (8 ) Is controlled.

Next, the operation of this embodiment based on the above configuration will be described. First, if the target position pulse is output from the position command of the position command circuit (1), the machine (8) moves until the target pulse is fed back from the position detector (9). At this time, when the machine (8) has little friction or the like or the response characteristic is made extremely high, the machine (8) goes too far, and the pulse amount according to this too far distance is returned to the side. At this time, the position deviation calculation circuit (2) outputs the position deviation having a polarity which is the reverse of the polarity thus far. The polarity holding circuit (10) to which this position deviation is input detects that the previous polarity has been inverted, and the dead band circuit (11) cancels the first pulse and outputs a control signal based on the hysteresis characteristic. The deviation is converged to "0" by operating the motor (4). Therefore, finally, the absolute position of the machine (8) is stably stopped at a position within the pulse canceled by the dead zone circuit (11), and a continuous phenomenon such as a limit cycle does not occur.

More specifically, the position command circuit (1) is "0".
When the machine (8) has gone too far by α pulses while the output is, the position deviation output of the position deviation calculation circuit (2) is
At this time, the deviation for the α pulse having the opposite polarity to the previous one is output. Due to the inverted polarity of the polarity holding circuit (10), the output of the dead band circuit (11) outputs (α-γ) pulses when the number of pulses to be canceled is pulse γ. At this time, the motor (4) moves between the backlashes of the gears, and (α-
γ) Continue to invert until it moves by the amount of pulses. Further, if the machine (8) goes too far in the reversing direction by β pulses due to this reversal, similarly, this time, (β-γ) pulses are output so as to move in the normal direction. When the above operation is repeated, the fluctuation in the backlash of the machine (8) is forcibly damped. Eventually the machine (8) will steadily rest at a position within the pulse γ that is being canceled.

〔The invention's effect〕

As described above, the positioning control device according to the present invention receives the position command data for instructing the moving position of the machine and the current position data representing the current position of the machine, calculates the deviation of each data, and calculates the polarity of the data. Depending on the forward rotation pulse or the reverse rotation pulse, position deviation calculation means for outputting a speed command of the number of pulses exemplifying the deviation, polarity holding means for holding the polarity of the calculation result of the position deviation calculation means, and The speed command from the position deviation computing means and the polarity from the polarity holding means are respectively inputted, and the control signal formed by the remaining pulses is canceled by canceling the first pulse of the speed command on condition that the polarities are inverted. Dead band forming means for outputting,
Since the motor is configured to rotate at a speed proportional to the control signal from the dead zone forming means and control the moving position of the machine, the final machine position can be quickly fixed, and the position control loop and the speed control loop can be fixed. The response characteristic can be improved.

[Brief description of drawings]

FIG. 1 is an overall circuit block diagram of a positioning control device according to an embodiment of the present invention, FIG. 2 is a control pulse output waveform diagram for operating this embodiment, and FIG. 3 is an overall circuit block diagram of a conventional device. FIG. 4 shows a control pulse waveform diagram for operating the conventional device. (1) is a position command circuit, (2) is a position deviation calculation circuit, (3) is a speed amplifier, (4) is a motor, (5) is a speed detector, (8) is a machine, and (9) is position detection. Vessel, (10) is the polarity holding circuit, and (11) is the dead zone circuit. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A position command data for commanding a moving position of a machine and a current position data representing a current position of a machine are respectively inputted, a deviation of each data is calculated, and a forward rotation pulse or a reverse rotation pulse is generated according to its polarity. The position deviation calculating means for outputting a deviation pulse having a pulse number proportional to the deviation, the polarity holding means for holding the polarity of the calculation result of the position deviation calculating means, and the deviation pulse from the position deviation calculating means And a polarity input from the polarity holding means, and a dead zone forming means for canceling the first pulse of the deviation pulse and outputting a control signal formed by the remaining pulses on condition that the polarity is inverted, A positioning control device characterized in that the moving position of the machine is controlled based on a control signal from the dead zone forming means.