JPH08234843A - Servo mechanism - Google Patents

Abstract

PURPOSE: To detect the rotating speed of a servo motor at high speed without separately providing any speed detector by deriving stored data as speed data based on the conversion data between the change data of a count value and the rotating speed of the servo motor. CONSTITUTION: A controlled variable such as the position of a moving object is detected by a detector 3 and a detection pulse from this detector 3 is counted by an up-down counter 11. The change data of the count value at the up-down counter 11 are latched for each prescribed sampling synchronization by a latch means 13 and those change data are stored in a storage means 14. Then, the stored data in the storage means 14 are derived as the speed data by a deriving means 12 based on the conversion data between the change data of the count value at the up-down counter 11 corresponding to the sampling sychronization and the rotating speed of a servo motor 2. Therefore, the data stored in the storage means 14 are utilized as the speed data as they are and the rotating speed detection of the servo motor 2 can be accelerated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo mechanism used in machine tools, carrier machines, robots, automatic assembly / processing machines, OA equipment and the like.

[0002]

2. Description of the Related Art Servo mechanisms are used in the mechanical parts of machine tools, transfer machines, robots, automatic assembly / processing machines, office automation equipment, etc. This is an automatic control system that is configured to follow an arbitrary change in a target value (input) with a controlled variable (output) such as position, azimuth, and attitude, and is generally configured as shown in FIG.

That is, a drive signal corresponding to the target rotation speed from the servo control device 1 is output to the servo motor 2 to drive the servo motor 2, and the servo motor 2 drives a moving body (not shown). For example, the position, which is the control amount of the moving body, is detected by the encoder 3 as a detector, and a detection pulse is output to the servo control device 1. Based on the detection pulse from the encoder 3, the servo control device 1 moves the position of the moving body. The rotation control of the servo motor 2 is performed so that the control amount such as the above or the rotation speed of the servo motor becomes a target value.

By the way, the conventional encoder 3 of this kind of servo mechanism can detect the control amount such as the position, azimuth and attitude of the moving body as described above, but cannot detect the rotation speed of the servo motor 2. Further, since it is not easy to detect the speed externally in the servo mechanism that does not have the speed detector, the output of the encoder 3 is conventionally used to derive the rotational speed of the servo motor 2. ,
For example, it is realized by the configuration as shown in FIG.

As shown in FIG. 5, a drive signal is output from the servo driver 1b to the servo motor 2 based on a control command from the control unit 1a to drive the servo motor 2,
The detection pulse from the encoder 3 is counted by the up / down counter 1c, the position of the moving body is detected by this count value, and on the other hand, from the timing of reading the count value of the counter 1c, that is, the constant reading timed by the timer 1d. The rotation speed of the servo motor 2 is calculated by the control unit 1a from the change in the count value over time.

[0006]

However, in the case of the conventional servomechanism not equipped with the speed detector as described above,
Since the rotation speed of the servo motor 2 must be obtained by calculation, it takes a long time to perform the calculation processing, and the rotation speed of the servo motor 2 cannot be detected at high speed.

Therefore, the present invention has been made in order to solve the above-mentioned problems, and does not require a speed detector separately and does not require the conventional calculation, and the rotation speed of the servomotor can be calculated. The purpose is to enable high-speed detection.

[0008]

The present invention provides a machine tool,
In the servo mechanism used in transfer machines, robots, automatic assembly / processing machines, office automation equipment, etc., a moving table, table,
A servo motor that drives a moving body such as a wheel, a detector that outputs a detection pulse by detecting a control amount such as the position, orientation, and attitude of the moving body, and an up-down counter that counts the number of the detection pulses. Latching means for latching change data of the count value of the up / down counter in every predetermined sampling cycle by the sampling means, storage means for storing the data latched by the latching means, and sampling cycle by the sampling means It is characterized by further comprising: deriving means for deriving stored data of the storage means as speed data based on conversion data of corresponding count value change of the up / down counter and rotation speed of the servo motor.

[0009]

According to the present invention, the detector detects the control amount of the position of the moving body, the detection pulse from the detector is counted by the up / down counter, and the latch means up / down the counter every predetermined sampling period. Change data of the count value is latched and the change data is stored in the storage means, and based on conversion data of the count value change data of the up / down counter and the rotation speed of the servo motor corresponding to the sampling period, the deriving means Since the storage data of the storage means is derived as the speed data by the above, it is not necessary to separately provide a speed detector, and it is necessary to calculate the rotation speed of the servo motor from the change of the count value at a constant reading time unlike the conventional case. The data stored in the storage means is directly used as speed data. Speed can be of the servo motor rotational speed.

[0010]

1 is a block diagram for explaining the principle of an embodiment of the present invention, FIG. 2 is an operation explanatory diagram, and FIG. 3 is a detailed block diagram.

First, the principle of the present invention will be described with reference to FIG.

As shown in FIG. 1, a moving body such as a moving table, a table, and a wheel (not shown) is driven by a servo motor 2 driven by a servo driver (not shown), and a position (that is, a controlled amount) of this moving body (that is, The rotation amount of the servo motor 2) is detected by the encoder 3 as a detector attached to the rotary shaft of the servo motor 2, and the detection pulse output from the encoder 3 is counted by the up / down counter 11.

Then, a sampling pulse (not shown) in the control unit 12 outputs a sampling pulse having a constant period to the latch unit 13, and the latch unit 13 counts the up-down counter 11 in each sampling period based on this sampling pulse. The change data of the value is latched, and the change data is stored in the storage means 14.

At this time, since the count value of the up / down counter 11 is cleared by the read control signal output from the control section 12 at the same time as the latch by the latch means 13, the sampling means is used as described above. The change data of the count value of the up / down counter 11 in each sampling cycle is the latch means 1.
3 will be latched.

On the other hand, the control section 12 has a function as a derivation means, and the built-in memory or the external memory of the control section 12 stores change data of the count value of the up / down counter 11 corresponding to the sampling cycle by the sampling means. Conversion data for the rotation speed of the servomotor 2 is stored in advance, and the control unit 12 searches and converts which of the conversion data the data stored in the storage means 14 corresponds to, and the result is converted to the servomotor. It is derived as speed data indicating the rotation speed of 2.

Therefore, it is not necessary to additionally provide a speed detector, and it is not necessary to calculate the rotation speed of the servo motor from the change of the count value in a constant reading time as in the conventional case, and the storage means 14 is therefore required. The data stored in can be used as it is as the speed data, and the speed of detection of the rotation speed of the servo motor 2 can be easily increased.

Further, even in the case of obtaining the acceleration, the velocity data thus obtained need only be differentiated once, and the acceleration data can be obtained easily and at high speed.

Further, since the history of the speed data is stored in the storage means 14, the speed change graph of the servo motor 2 as shown in FIG. 2 can be easily obtained.

By the way, a concrete configuration for realizing the principle of FIG. 1 is as shown in, for example, FIG. 3, in which the first and second counters composed of 24 bit counters correspond to the up / down counter 11, and the latch and multiplexer operates. This corresponds to the latch unit 13, the memory including the D-RAM corresponds to the storage unit 14, and the ASIC and the counter controller correspond to the control unit 12.

Then, the detection pulse from the encoder 3 is input to the first and second counters, which are the up / down counters 11, via the connector CN2, and the first and second counters are operated by the read control signals from the counter controller. The detection pulse is counted, and the first and second latch and multiplexer are used based on the sampling pulse input through the counter controller.
The count value of the counter is latched and the count values of the first and second counters are cleared, while the data latched by the latch and multiplexer by the ASIC is stored in the memory.

Further, the change data of the count values of the first and second counters and the servo motor 2 corresponding to the sampling period of the sampling pulse generated by the ASIC.
The converted data with respect to the rotation speed is previously stored in the memory, and the latch data of the latch and multiplexer stored in the memory is converted into speed data based on the converted data.

In FIG. 3, a connector CN1 is used to obtain a sampling pulse from the outside, a general-purpose counter composed of a 16-bit counter is used when performing a predetermined timer operation, and a bus interface and an expansion bus are shown. Not what is used to connect to a personal computer.

In the above embodiment, the case where the sampling period is fixed has been described, but the sampling period may be variable, and in this case, the up / down counter 11 corresponding to each variable sampling period. The conversion data of the count value change data and the rotation speed of the servo motor 2 are stored in the memory in advance, and the conversion data corresponding to the changed sampling cycle is selected from the plurality of conversion data. The speed should be converted.

Further, in the above embodiment, the case where the detector is an encoder has been described, but the detector is not limited to this, and of course a linear gauge may be used, for example.

Further, it goes without saying that the control amount of the moving body is not limited to the above-mentioned position, but the control amount of the azimuth, the posture and the like may be detected by the detector.

[0026]

As described above, according to the present invention, the up / down counter counts the detection pulses which are manually output by detecting the control amount such as the position of the moving body by the detector and the predetermined sampling by the latch means. The change data of the count value of the up / down counter in each cycle is latched and the change data is stored in the storage means, and the change data of the count value of the up / down counter corresponding to the sampling cycle and the rotation speed of the servo motor are converted. Since the storage data of the storage means is derived as speed data by the derivation means based on the data, it is not necessary to provide a speed detector separately, and the rotation of the servo motor is changed from the change of the count value at a constant reading time unlike the conventional case. It is not necessary to calculate the speed, and the data stored in the storage means can be used as is. Can be used as, it is possible to shorten the processing time, it is possible to increase the speed of the servo motor rotational speed is suitable for servo control that requires high-speed control.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating the principle of an embodiment of the present invention.

FIG. 2 is a diagram illustrating the operation of the embodiment.

FIG. 3 is a detailed block diagram of one embodiment.

FIG. 4 is a block diagram of a general servo mechanism.

FIG. 5 is a block diagram of a conventional example.

[Explanation of symbols]

 2 servo motor 3 encoder 11 up / down counter 12 controller 13 latch means 14 storage means

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Claims (1)

[Claims] 1. A servo mechanism used in a machine tool, a carrier machine, a robot, an automatic assembly / processing machine, an OA equipment, or the like, and a servo motor for driving a moving body such as a moving table, a table, or a wheel, and the moving body. Detector for detecting a control amount such as position, azimuth, attitude, etc., and outputting a detection pulse, an up / down counter for counting the number of the detection pulses, and an up / down counter for each predetermined sampling period by sampling means. Latch means for latching the count value change data, storage means for storing the data latched by the latch means, change data of the count value of the up / down counter corresponding to the sampling cycle by the sampling means, and a servo motor The stored data in the storage means is speeded up based on the converted data of the rotation speed of And a deriving means for deriving as degree data.