JPS61290512A - Multipoint position control system - Google Patents

Abstract

PURPOSE:To execute a multipoint position control of an object by a simple circuit, by controlling a motor by comparing a position signal of the object and a multipoint position analog data of the object, and moving the object to a prescribed position. CONSTITUTION:A position signal generating circuit 3 outputs an analog signal correlated to a position of a movable object, through a potentiometer 31. A memory 1 stores plural position control data of the movable object driven by a motor 5, and outputs the position control data of an address which has been designated by a digital signal. This output signal is converted to an analog through a D/A conversion circuit 2. A differential amplifier 4 rotates the motor 5 in the direction where an output of a position signal approaches an output of the circuit 2. In this state, when a difference of inputted voltages becomes '0', the movable object stops at a prescribed position. When executing a position control to the next position, the desital signal for designating an address is sent out to the memory 1.

Description

[Detailed Description of the Invention] [Summary] This is a position control method for an object driven by a motor, which converts the object position signal and the data in a memory storing data on the multi-point positions of the object into a digital/analog signal conversion circuit. Through the comparison, the motor can be configured to be controlled, and by addressing the memory, the object can be moved to a predetermined position.

[Industrial application field]

The present invention relates to position control of a movable object having a plurality of predetermined positions.

In the field of industrial machinery or measuring equipment, the movement position or rotation angle of an object is determined, and various control methods are used to control the drive motor and move the object to the specified position. There is.

In that case, the predetermined position data of the movable object and the signal detected using a sensor of the position occupied by the movable object are compared in analog or digital quantities, the motor is rotated in a direction to reduce the difference, and the predetermined data and the position detection signal are compared. The motor is controlled to stop at the point where the correlation values of the two match.

When a large number of such predetermined positions are required,
Requires multiple circuits to store predetermined position data;
The circuit configuration becomes complicated, or the position sensor and comparison circuit become expensive.

Therefore, there is a need for a position control system that can move objects to a large number of desired positions with a simple configuration.

[Conventional technology]

Let us take as an example a control method used for rotational position control.

In rotational position control, a rotary encoder that generates pulses at every predetermined rotation angle is attached to the motor shaft for position detection, and a pulse counter counts the number of pulses from the motor's reference position; A comparing circuit calculates the difference in the number of pulses between the data in the register storing the number of pulses as data and the aforementioned pulses, and when the motor rotates in the direction of a predetermined position, a circuit is used to reduce the difference in the number of pulses.
The motor is rotated until the difference becomes O.

When changing the position of an object, the data in another register is read and the object is moved by controlling the procedure described above.

[Problem that the invention seeks to solve]

In this conventional method, in order to use an encoder as a position detection sensor, the control method compares the number of pulses, and is equipped with a counter for counting pulses and registers for the number of multi-point positions, and the data value read from the register and The circuit configuration of the comparator circuit for comparison is complicated, and when used in fields that do not require high accuracy, the performance becomes excessive and expensive.

The present invention was created in view of these points, and an object of the present invention is to provide a motor-driven multi-point position control system that can perform multi-point position control with a simple configuration.

[Means for solving problems]

FIG. 1 shows a block diagram of the principle of the multi-point position control system of the present invention.

In FIG. 1, 2 is a memory storing position control data for the moving position of an object, and 2 is a digital/analog signal conversion circuit which converts digital data read from the memory 1 into an analog signal.

Reference numeral 3 denotes a position signal generation circuit, which extracts the position of an object from a reference point as an analog signal.

Reference numeral 4 denotes a differential amplifier circuit, which receives the output of the digital/analog signal conversion circuit 2 and the output of the position signal generation circuit 3 as inputs, and uses the difference between them to rotate the drive motor 5.

Therefore, the entire system is configured as a negative feedback circuit.

[Effect]

If the predetermined position signal is stored in a memory, for example a semiconductor ROM, in the form of digital data, a large amount of data can be stored in an extremely small space.

Furthermore, by detecting the position of the object with a sensor and converting the generated signal into an analog signal, an inexpensive potentiometer, for example, can be used as the sensor.

A simple method can be used in which a voltage is applied to both ends of a potentiometer, the slider is linked to the position of a movable object, and an analog signal is directly taken out as a voltage divider.

The present invention makes it possible to perform multi-point position control with a simple circuit configuration by converting predetermined position data into digital quantities and converting the position signal of a movable object into analog quantities.

〔Example〕

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

FIG. 2 is a block diagram of an embodiment of the present invention, and FIG. 3 is an explanatory diagram of rotation angle control.

Note that the same reference numerals indicate the same objects throughout the figures.

The position signal generation circuit 3 includes a potentiometer 31 and an analog signal circuit 32.

The potentiometer 31 is attached to the drive shaft of the motor 5 via the coupling 11, and an analog signal corresponding to the rotation angle of the motor 5 is outputted by the analog signal circuit 32. For example, the potentiometer 31 has a voltage supplied to both ends thereof. The voltage is divided and output.

On the other hand, the rotation angle of the controlled rotation shaft 10 is controlled by the motor 5.
It is driven from a rotating shaft of the motor via a transmission gear 12.

Therefore, since the voltage obtained from the potentiometer 31 is kept in correlation with the controlled rotating wheel 10 by the transmission gear 12, the installation location of the potentiometer 31 in FIG. Not contrary to

In order to smoothly control the entire device, it is necessary to monitor the condition at various locations in the device, and a condition detection sensor 6 is installed.

One of them is a state detection sensor 6 for detecting the rotation limit of the controlled rotating shaft 10 to prevent damage caused by excessive rotation.

For example, a photoelectric sensor is used as the state detection sensor 6, and a transmission gear 12 is connected between a light source and a photoelectric converter installed facing each other.
However, when it rotates to the critical angle position, the photoelectric converter receives the light through the light passing hole opened at that position and generates an electrical signal, which is converted into a predetermined digital signal and sent to the memory 1. Enter address bus.

A desired rotation angle position is given in advance by a digital signal specifying an address in the memory 1, and when that signal is input to the memory 1, data at the corresponding address is output.

The output of the digital/analog signal conversion circuit Ia2 and the output of the position signal generation circuit 3 both have the same rotation angle correlation position,
The same voltage is input to the differential amplifier circuit 4.

The differential amplifier circuit 4 rotates the motor 5 in a direction in which the output of the first signal approaches the output of the digital/analog signal conversion circuit 2.

The motor 5 is a DC motor, and rotates in positive and reverse directions depending on the positive and negative sides of the applied voltage, and the differential amplifier circuit 4 applies positive and negative voltages to the motor 5 depending on the positive and negative sides of the input difference.

Then, the difference between the voltages input to the differential amplifier circuit 4 becomes O, the motor 4 stops, and the controlled rotary wheel 10 stands still at a predetermined rotation angle position.

In order to rotate to the next rotation angle position, a digital signal specifying the address is sent to the memory l.

Further, the differential amplifier circuit 4 sends out a busy signal indicating that the motor 5 is rotating to necessary circuits.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to perform position control of multiple points with a simple circuit configuration, and it is extremely useful in practice.

[Brief Description of the Drawings] Figure 1 is a principle block diagram of the multi-point position control method of the present invention, Figure 2 is a block diagram of an embodiment of the present invention, and Figure 3 is an explanatory diagram of rotation angle control. . In the figure, 1 is a memory, 2 is a digital/analog signal conversion circuit, 3 is a position signal generation circuit, 4 is a differential amplifier circuit, and 5 is a motor. #FJfi4W7-0.7gl! III Figure

Claims (1)

[Scope of Claims] A memory (1) that stores a plurality of position control data of a movable object driven by a motor (5) and outputs the position control data at an address specified by a digital signal; a digital/analog signal conversion circuit (2) that converts the output data of 1) into an analog signal; a position signal generation circuit (3) that generates an analog signal correlated to the position of the movable object; and the position signal generation circuit. (3) and a differential amplifier circuit (4) that amplifies the difference between the output of the digital/analog signal conversion circuit; and the motor (5) that drives the movable object using the output of the differential amplifier circuit. A multi-point position control system, characterized in that the position of the movable object is controlled by a digital signal specifying an address in the memory (1).