JPH0460708A - Rotating/moving device for object and position detection method for its object - Google Patents

Abstract

PURPOSE:To detect a highly precise absolute position with an inexpensive sensor for absolute position detection by using a motor and an incremental rotary encoder by means of combining them. CONSTITUTION:The sensor for absolute position detection 6 is fitted to the shaft of a rotary table 2 as a load which operates by the motion of a motor 3 shaft through the incremental rotary encoder 4 fitted to the shaft of the motor 3 and a reduction gear 5. The sensor for absolute position detection 6 outputs data on an absolute position in the movable range of the load having an object, clears the pulse count value of the incremental rotary encoder 4 when data changes, counts the pulse of the incremental rotary encoder 4 and detects the absolute position higher than the resolution of the sensor for absolute position detection 6.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a rotational movement device for moving an object to a fixed position and a method for detecting the absolute position of the object.

(Prior art and its problems) Conventionally, this type of position detection means has been to count the number of pulses of an incremental rotary encoder mounted on the motor shaft, and to detect the position by relative movement. Ta.

However, the load is generally moved to a certain predetermined position, and when the power is turned on (counter value is clear), a certain predetermined position (mechanical origin) is searched, and at that position, a certain predetermined It was necessary to add the received value to the counter.

By performing this "work," by relative movement,
Movement to a certain defined position can be achieved.

For this reason, an origin search operation was always required when the power was turned on, but in order to avoid the origin search operation when the power was turned on,
Counter values were stored sequentially and used for memory back-amplification.

However, problems with data reliability due to battery voltage drop due to long-term storage, instantaneous power outages, and count deviations due to coasting of the load after the power is cut off result in relative movement deviations, resulting in accurate positioning. There was a problem that the counter could not be moved to (the counter does not count after a momentary power outage or power cut).

Furthermore, if the counter value goes off due to noise during operation, or if the position of the load is moved due to external force during a break (while the power is cut off), it is necessary to search for the origin again when restarting. Ta.

On the other hand, with the position detection method in which an absolute position detection sensor is attached to the motor shaft, the resolution of the absolute position detection sensor is limited, making it difficult to detect the position with high precision. However, the absolute position could not be detected unless it was used within a limited range (the range of one rotation of the motor).

In general, this type of position detection requires the use of expensive and highly accurate sensors, and the installation of absolute position detection sensors requires highly accurate installation and electrical correction means. However, installation errors could only be corrected within the resolution of the absolute position detection sensor.

In order to solve the above-mentioned problems, the present invention detects the absolute position of an object in a rotary movement device for an object without using an expensive and highly accurate sensor for detecting the absolute position. No installation work required.
It is an object of the present invention to provide a rotationally moving device for an object that can obtain high resolution and a method for detecting the position of the object.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a rotary movement device for moving an object to a fixed position, which includes an incremental rotary encoder mounted on a motor shaft, and a movement of the motor shaft. an absolute position detection sensor that is attached to the shaft of the load having the object that is operated by the object, and has a lower resolution than the incremental rotary encoder, a signal from the absolute position detection sensor, and the incremental rotary encoder. A control device that counts the number of pulses in the frame, and the absolute position detection sensor,
Absolute position data is output in the movable range of the load having the object, and the absolute position is detected based on the relationship with the pulse count value of the incremental encoder, regardless of the mounting accuracy of the absolute position detection sensor. The sensor is equipped with means for detecting an absolute position that exceeds the resolution of the sensor.

In addition, in a method for detecting the position of an object in a rotary moving device that moves an object to a fixed position, incremental measurements are performed using an incremental rotary encoder attached to a motor shaft, and the object that moves in response to the movement of the motor shaft is detected. The absolute position is measured by an absolute position detection sensor that is attached to the shaft of the load and has lower resolution than the incremental rotary encoder, and the signal from the absolute position detection sensor and the signal from the incremental rotary encoder are The number of pulses is counted by the control device, and the absolute position detection sensor outputs absolute position data in the movable range of the load having the object, and when the data changes, the pulse count value of the incremental rotary encoder is is cleared, the pulses of the incremental rotary encoder are counted, and an absolute position exceeding the resolution of the absolute position detection sensor is detected.

(Operation) According to the present invention, as described above, a signal from an absolute position detection sensor attached to the shaft of a load having an object that moves in response to the movement of the motor shaft, and an incremental sensor attached to the motor shaft are detected. type rotary encoder (A phase, B phase
In combination with phase) pulse signals, the absolute position can be detected with an accuracy approximately equivalent to the resolution of an incremental rotary encoder.

Therefore, a highly accurate absolute position can be detected using an inexpensive absolute position detection sensor.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

First, the principle of the present invention will be explained.

an incremental type rotary encoder mounted on a motor shaft; and an absolute position detection sensor installed on the shaft of a load having the object that operates in response to the movement of the motor shaft and having a lower resolution than the incremental type rotary encoder. , the output of the absolute position detection sensor is Z, and the total value of the amplifier count and down-count value of the incremental rotary encoder is I, then the absolute position χ is as follows: X=KIXZ+2Xl... (1) (Tatashi, K1, and K2 are coefficients converted into sensor output images or angles, and the count value in ■ shall be cleared once when Z changes. Also, due to the structure,
Accuracy of Z (There is a relationship with the accuracy of Absolute position can be detected by managing the pulse count value.

In the above equation (1), the first item Z is rough absolute position data, and the absolute position detection sensor itself can be inexpensive. Rather, it can be seen that the position accuracy is determined by the second item I.

Furthermore, by setting the count value in ■ to an arbitrary count value once Z changes (adding subsequent pulses), the mounting accuracy of the absolute position detection sensor can be corrected within the resolution range in ■. can do.

FIG. 1 shows the configuration of a rotary movement device showing an embodiment of the present invention.

In this figure, an incremental rotary encoder 4 is attached to the shaft of a motor 3, and an absolute position detection sensor is attached to the shaft of a rotary table 2, which is a load that operates in conjunction with the three axes of the motor, via a reducer 5. 6 is installed.

A workpiece 1 is set on the rotary table 2, and the workpiece 1 is a device that rotates and moves to a predetermined position.

Therefore, when the motor 3 performs rotational motion, the incremental rotary encoder 4 outputs pulses.

Further, the rotary motion of the motor 3 is decelerated via the reducer 5, and the rotary table 2 rotates.

Every time the rotary table 2 rotates once, the absolute position detection sensor 6 also rotates once. This absolute position detection sensor 6 uses the absolute position as a digital signal to detect AU, AI, etc. in FIG.
... is output.

In Fig. 2, the minimum unit bit of the digital signal output of the absolute position detection sensor 6 is (AO), and the minimum resolution is (A
).

Also, let the pulse of the incremental rotary encoder be (CP) and the resolution of one pulse be (P).

Now, the minimum unit bit of the absolute position detection sensor 6 (A
By clearing the counter in Figure 3 at the point (L) where O) changes and counting the number of pulses of CP (1),
The absolute position at any point (X) can be determined using the above equation (1).

In addition, the minimum unit pitch of the absolute position detection sensor 6) (AO
) is changed, by setting arbitrary data in the counter shown in FIG. 3, the error in the installation of the absolute position detection sensor 6 can be corrected within the resolution of the incremental rotary encoder.

Note that the present invention is not limited to the above embodiments,
Various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

(Effects of the Invention) As described above in detail, according to the present invention, the following effects can be achieved.

(1) Since the accuracy of the absolute position is determined by the resolution of the incremental rotary encoder, it is possible to detect the absolute position over a wide range and with high precision at low cost without using an expensive absolute position detection sensor.

(2) The mounting accuracy of the absolute position detection sensor can be corrected within the resolution range of the incremental rotary encoder, making it easy to mount the absolute position detection sensor.

(3) Even if a momentary power outage occurs during movement and the load coasts (without installing an external home sensor and searching for the home sensor once), it will continue to move to the absolute position after power is restored. can be made to do so.

Therefore, it is extremely effective in applications where objects are moved to a predetermined work location.

(4) It is highly reliable because there is no need to back-amplify the position data from the memory power supply when t#i is off, and when @B is off, there is a possibility that the count value may deviate from the count value due to coasting of the load, or the load may be affected by external force. Even if the position of the object shifts, it does not result in a relative displacement shift, and the object can be moved to a predetermined accurate position.

(5) The absolute position detection sensor outputs absolute position data within the load's movable range, and based on the pulse count value of the incremental rotary encoder, the absolute position detection sensor outputs absolute position data regardless of the installation accuracy of the absolute position detection sensor. Absolute position detection can be performed that exceeds the resolution of the sensor.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a rotational movement device showing an embodiment of the present invention;
FIG. 2 is a timing chart of the output signal of the sensor of the rotational movement device, and FIG. 3 is a schematic control circuit diagram of the rotational movement device. 1... Work (object), 2... Rotary table (load), 3... Motor, 4... Incremental type rotary encoder, 5... Reducer, 6... Absolute position detection sensor . Patent applicant: Akatsuki Electric Manufacturing Co., Ltd.

Claims (2)

[Claims] (1) A rotational movement device for moving an object to a fixed position, which includes: (a) an incremental rotary encoder mounted on a motor shaft; and (b) a shaft of a load having the object that operates in response to the movement of the motor shaft. (c) a control device that counts signals from the absolute position detection sensor and the number of pulses from the incremental rotary encoder; (d) The absolute position detection sensor outputs absolute position data in the movable range of the load having the object, and the absolute position data is determined based on the relationship with the pulse count value of the incremental rotary encoder. 2. A rotational movement device for an object, comprising: means for detecting an absolute position that exceeds the resolution of the absolute position detection sensor, regardless of mounting accuracy. (2) In a method for detecting the position of an object in a rotary moving device that moves the object to a fixed position, (a) incremental measurements are performed using an incremental rotary encoder mounted on the motor shaft, and (b) movement of the motor shaft is detected. The absolute position is measured by an absolute position detection sensor that is attached to the shaft of the load having the object that is operated by the object and has a lower resolution than the incremental rotary encoder; The signal and the number of pulses from the incremental rotary encoder are counted by a control device; (d) the absolute position detection sensor outputs absolute position data in the movable range of the load having the object; An object in a rotational movement device that clears the pulse count value of the incremental rotary encoder at the time of change, counts the pulses of the incremental rotary encoder, and detects an absolute position exceeding the resolution of the absolute position detection sensor. position detection method.