JPH0293914A - Method and device for accurate positioning - Google Patents

Abstract

PURPOSE:To attain accurate positioning even when an accurate angle sensor is disconnected by storing the error data of an accurate angle sensor, and driving a controller by using the data. CONSTITUTION:The title device is provided with an adder 13 for comparing an output signal from a motor rotational angle measuring device 11 with a highly accurate position signal from the accurate angle sensor 12 to form an error signal E. The error signal E is stored in a memory 14 by using the rotational angle signal of a motor as its address. When the error signals of respective rotational angles of the motor are stored over the whole angle 360 deg., the sensor 12 is detached. After storing the practical error signal E of a subtracter 3 corresponding to the rotational angle of the motor 2 in the memory 14, the rotational angle of the motor 2 is used as an address signal and the contents, i.e. the error signal, of the memory 14 are read out by specifying the address. Thus, highly accurate positioning can be attained.

Description

Detailed Description of the Invention Field of the Invention The present invention relates to a high-precision positioning method and device, and in particular to a speed reducer connected to the motor, which drives a motor using a controller based on an input positioning command. The present invention relates to a method and apparatus for positioning an object such as an indexing board with high accuracy by detecting the rotation angle of a motor and feeding back a positioning command signal to a controller.

Conventional technology A controller is used to drive a motor based on an input positioning command, a reducer connected to the motor positions an object such as an indexing board, and the rotation angle of the motor is detected to generate a positioning command signal. Feedback to a controller is already being used to position an object with high precision.

This positioning method is very common and is often used because it provides a certain degree of accuracy. For example, it is used for positioning an indexing board, etc., and has an accuracy of about 15 to 20 seconds. This accuracy is not a problem in normal cases, but
This is insufficient for precision grade indexing machines. For this reason, in the case of a precision indexing machine, j:.

In this method, a high-precision sensor is attached to the output of the speed reducer to perform high-precision indexing of, for example, about 1 to 3 seconds.

Problems to be Solved by the Invention If the above-mentioned high-precision indexing of about 1 to 3 seconds is performed, the cost of the high-precision sensor installed at the output of the reducer becomes high, and the following are: Accordingly, the cost of the entire positioning system becomes high.

Therefore, an object of the present invention is to provide a positioning method and apparatus that can perform highly accurate positioning using inexpensive angle sensors used in general positioning systems.

Means for Solving the Problems In order to achieve the object, according to the present invention, the rotation angle of the motor is measured from a detection signal of the rotation angle of the motor,
On the other hand, the output of the reducer detects the actual position of the object,
Compare the angle signal of the motor with the position signal of the object to generate an error signal; Store the error signal in a memory using the motor angle signal as an address; and use the error signal from the memory to send the error signal to the positioning system. The positioning signal is feedback-controlled, and the step of detecting the position of the object and the step of storing it in the memory are performed for correction, and after the correction, the error signal is adjusted by the angle signal of the motor. A positioning method is provided, characterized in that it is read from a memory.

Further, according to the present invention, in order to achieve the above object, a controller that drives a motor based on a positioning command;
a reducer connected to the motor to position the object;
A positioning device comprising an angle sensor that detects the rotation angle of a motor and feeds back the angle signal to control a positioning command signal input to the controller is improved, and in the present invention, this positioning device A measuring means that is connected to the output of the sensor and measures the rotation angle of the motor, a precision angle sensor that detects the position of the actual object with high accuracy from the output of the reducer, and the rotation of the motor from the measuring means. means for generating an error signal by comparing the angle signal with a high-precision position signal from the precision angle sensor; storing the error signal as an address using the rotation angle signal of the motor; and reading the error signal using the address signal. a memory connected to input an error signal to the controller, and the precision angle sensor is configured to be removable from the device after writing the error signal to the memory.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

In the drawings, a positioning device 1 according to the present invention drives a motor 2 based on a positioning command I, and operates, for example, an indexing board (not shown) via a reduction gear 3 by driving the motor 2. It is configured to position an object placed on the separate plate.

In order to position an object on the indexing board, the positioning device 1 is provided with a controller 4 that receives a positioning command signal I, and a driver 5 that drives the motor 2 is connected to the controller 4. A speed reducer 3 is connected to the output shaft of the motor 2 driven by the driver 5, and in this embodiment, the output shaft of the speed reducer 3 is connected so as to position the indexing board. It should be noted that a flexible mesh large gear device known as a so-called harmonic gear is suitable as the reducer used in this example because it performs accurate angle transmission and has little play.

When the positioning command signal I is input to the controller 4, the controller 4 sends a signal to the driver 5, and the motor 2
to drive. By driving this motor 2, an indexing board is driven via a reduction gear 3. In this drive, an angle sensor 6 with normal accuracy is connected to the output shaft of the motor 2.
The rotation angle of the motor 2 is detected, and this angle is input to an adder (actually a subtracter) 7 provided at the input of the controller 4 and fed back. It may be.

The configuration and operation described so far are almost the same as those in conventional positioning devices, and is a basic positioning device of the so-called feedback control type.

In the present invention, feedback of data from the angle sensor 6 is further added. In this example, the output of the angle sensor 6 is differentiated by a differentiator 8 to produce an angular velocity signal, and this signal is input to an adder (actually, a subtracter) 9 between the controller 4 and the driver 5, and the 5
The motor 2.'r) is configured to adjust the drive by the motor 2.'r).

In the present invention, the angle sensor 6 is connected to the output of the angle sensor 6, and the rotation angle of the motor is determined by an absolute angle (not a relative angle from the previous angle to the current angle, but an absolute angle from a reference angle (for example, 0°)). motor rotation angle measuring device 11
This measuring instrument 11 may be provided with a counter for integration (or, if the angle sensor 6 is an absolute encoder, it may be a register).

Also, in the present invention, a high precision precision angle sensor 12 is used which detects the actual position of the object with high accuracy from the output of the deceleration@3. In other words, the accuracy of this angle sensor 12 is high (and the cost is high, but -
Since it is used occasionally, this angle sensor 12 does not add cost to the positioning method and apparatus of the present invention. This point will be discussed further later.

An adder (actually a subtracter) 13 is provided which compares the output signal of the motor rotation angle measuring device 11 with the high precision position signal from the precision angle sensor 12 to generate an error signal E. In the present invention, the error signal E is stored in the memory 14 using the rotation angle signal of the motor as an address. For this storage, the error signal E from the adder 13 is connected to the data input bus of the memory, and the motor rotation angle measuring device 11
The output of is connected to the address bus of memory 14,
An error signal E corresponding to the absolute angle of the motor rotation angle measuring device 11 is stored at the address.

Note that this memory 14 is preferably a non-volatile memory whose contents do not disappear once they are stored. After the error signal for each rotation angle of the motor is stored over the entire 360° angle, the precision angle sensor 12 is removed.

Subtractor 3 corresponding to the rotation angle of motor 2 in Memo 'J14
After the actual error signal E of is stored: Well, the motor 2 of
The rotation angle becomes an address signal, and the contents of the memory 14, that is, the error signal, are read out to the reading section 15 by specifying this address. This error signal is transmitted to the controller 4
The adder 70 at the 0 input stage is fed back to the adder (actually a subtracter) 16 provided at the input stage, and a more accurate correction signal is input to the controller 4 to perform highly accurate positioning.

Effects of the Invention According to the present invention, since the error data of the precision angle sensor is stored and the controller is operated using this data, extremely high precision positioning is possible even if the precision angle sensor is separated. Go naru. In actual results, highly accurate positioning of about 1 to 2 seconds was obtained. Therefore, during actual operation, the same positioning accuracy as using an ultra-precise angle sensor can be obtained without requiring a precise angle sensor. According to the device of the present invention, a precise angle sensor is only required temporarily and is not required during actual operation, so that the overall cost of the device can be kept low.

[Brief explanation of drawings]

The drawing is a circuit diagram of a device implementing the positioning method according to the invention. Explanation of symbols 1... Positioning device 2... Motor 3... Speed reducer 4... Controller 5... Driver 6...・・・
Angle sensor 8...Differentiator 11...
...Rotation angle measuring device 12...Precision grade angle sensor 15...Error signal memory

Claims (2)

[Claims] (1) A positioning method in which a motor is driven based on a positioning command, a reduction gear connected to the motor positions the object, and the rotation angle of the motor is detected and fed back to control the positioning command signal. In,
The rotation angle of the motor is measured from a detection signal of the rotation angle of the motor, the actual position of the object is detected from the output of the reducer, and the angle signal of the motor is compared with the position signal of the object. the step of detecting the position of the object; A positioning method characterized in that the storing step in a memory is performed for correction, and after the correction, the error signal is read out from the memory by the angle signal of the motor. (2) A controller that drives the motor based on the positioning command, a reducer that is connected to the motor to position the object, and a positioning command that detects the rotation angle of the motor and inputs the angle signal to the controller. A positioning device comprising: an angle sensor that feeds back a signal to control; a measuring means that is connected to the output of the angle sensor and measures the rotation angle of the motor; and a measuring means that measures the actual position of the object from the output of the reducer. a precision angle sensor that detects with high accuracy; a means for generating an error signal by comparing the rotation angle signal of the motor from the measuring means with a high precision position signal from the precision angle sensor; The precision angle sensor includes a memory connected to store a motor rotation angle signal as an address and input an error signal read out by the address signal to the controller, and the precision angle sensor inputs the error signal to the memory. A positioning device characterized in that it is configured to be detachable from the device after writing.