JP4577979B2 - Servo motor with reduction gear and drive control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a servomotor with a reduction gear and a drive control device thereof, and more particularly to a technique for generalizing the drive control device.
[0002]
[Prior art]
In the servo motor with reducer, the detection signal of the encoder attached to the motor rotation shaft (reduction gear input shaft) is used so that the load side member connected to the reduction gear output shaft is at the target rotation position or movement position. Based on this, drive control of the motor is performed. In such a servomotor drive controller with a reducer, at the initial setting, the maximum drive current, rated current, and position control are used according to the type, model number, and speed ratio of the reducer attached to the servomotor with a reducer. It is necessary to set and change various gains.
[0003]
In order to improve the positioning accuracy of the output shaft of the servomotor with a reduction gear, it is desirable to measure the angle transmission error of the reduction gear in advance and correct the position control based on the measured error data.
[0004]
[Problems to be solved by the invention]
As described above, in the servo motor with a reduction gear, if the reduction gear combined with the motor is different, it is necessary to change the setting on the drive control device side in accordance with the model, model number, speed ratio, and the like. This setting or setting change takes time. Further, since it is necessary to set the drive control device at 1: 1 with respect to the servo motor with a reduction gear, in a strict sense, the drive control device is not generalized.
[0005]
Similarly, when the angle transmission error data of the speed reducer is stored and held and the position control is corrected based on this data, the angle transmission error has individual differences, so that such data is stored and held in the drive control device. In this case, the servomotor with a speed reducer and the drive control device are completely in a 1: 1 relationship, which is disadvantageous for generalization of the drive control device.
[0006]
In view of the above, an object of the present invention is to propose a servo motor with a reduction gear having a configuration advantageous for generalization of a drive control device.
[0007]
Another object of the present invention is to propose such a drive control device for a servo motor with a reduction gear.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides:
In a servomotor with a speed reducer comprising a motor (4), an encoder (7) for detecting the rotational position of the motor rotating shaft (5), and a speed reducer (6) connected to the motor rotating shaft (5) ,
The speed reducer (6) is a wave gear speed reducer;
The encoder (7)
A detection unit (11) comprising a rotary disk with slits and an optical detection element attached to the motor rotation shaft (5);
A signal processing unit (12) for encoding a detection signal output from the detection unit (11) and converting it into a pulse signal representing a rotational position;
An interface (13) for transmitting the encode signal generated by the signal processing unit (12) to a drive control device (3) for driving and controlling the motor (4);
Initial setting information (15) regarding the speed reducer including the model, model number, and speed ratio of the speed reducer (6), and error correction data for compensating for positioning errors caused by the angle transmission error of the speed reducer (6) A storage unit (14) in which (16) is stored and held in advance;
Positioning caused by an angle transmission error of the speed reducer (6) by adding a correction pulse number to the encode signal output from the signal processing unit (12) based on the error correction data (16). A correction unit (19) that removes an error and outputs the corrected encoded signal obtained thereby to the drive control device (3) side through the interface (13);
When the power is turned on and when a transfer request is received from the drive control device (3) side, the initial setting information (15) related to the speed reducer (6) stored in the storage unit (14) is stored in the storage unit (14). An information output unit (18) for outputting to the drive control device (3) side through an interface (13),
The error correction data (16) is angle transmission error correction data for each rotation angle position of one rotation of the speed reducer input shaft detected by the encoder (7).
[0009]
Next, the present invention is a drive control device (3) for driving and controlling the servo motor with a speed reducer having the above-described configuration,
A feedback control unit that receives the corrected encoded signal from the encoder (7) and feedback-controls the motor (4) based on the corrected encoded signal and a position command signal supplied from a host device. 22)
A reading unit (23) for reading the initial setting information (15) held in the storage unit (14) of the encoder (7);
An initial setting unit (24) for performing initial setting of a maximum current value and a rated current value for driving the motor and a gain for position feedback control based on the read initial setting information (15) when the power is turned on. It is characterized by having.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of a servo motor with a reduction gear and a drive control apparatus thereof to which the present invention is applied will be described with reference to the drawings.
[0011]
FIG. 1 is a schematic block diagram showing an example of a servo motor system with a reduction gear to which the present invention is applied. As shown in this figure, the servomotor system 1 with a speed reducer of this example has an actuator 2 and a drive control device 3 that drives and controls the actuator 2.
[0012]
The actuator 2 includes a motor 4, a speed reducer 6 whose input side is connected to the motor rotation shaft 5, and an encoder 7 that detects the rotational position of the motor rotation shaft 5, and a speed reducer output shaft 8 (actuator) A load side member (not shown) connected to the output shaft) is driven.
[0013]
The encoder 7 of this example encodes a detection unit 11 composed of a rotating disk with slits and an optical detection element attached to the motor rotating shaft 5, and encodes a detection signal output therefrom to convert it into a pulse signal representing a rotational position. And an interface 13 for transmitting the generated encoded signal to the drive control device 3 side.
[0014]
In addition to this, the encoder 7 of this example includes a storage unit 14, in which initial setting information 15 regarding the speed reducer including the model, model number, speed ratio, and the like of the speed reducer 6, Error correction data 16 for compensating for the positioning error of the actuator 2 caused by the angle transmission error is stored and held in advance. The encoder 7 includes an information output unit 18 and a correction unit 19. The information output unit 18 is stored and held in the storage unit 14 when the power is turned on and when a transfer request is received from the drive control device 3 side. The initial setting information 15 regarding the reduction gear is output to the drive control device 3 via the interface 13. Further, the correction unit 19 adds the number of pulses for correction to the encode signal output from the signal processing unit 12 based on the error correction data 16, and removes the positioning error caused by the angle transmission error of the speed reducer. Is. The corrected encode signal is output to the drive control device 3 via the interface 13.
[0015]
Here, the speed reducer 6 of the present example is a wave gear speed reducer, and includes an annular rigid internal gear, an annular flexible external gear disposed on the inner side, and a wave generator fitted on the inner side. It is configured. In a typical configuration, the wave generator has an elliptical shape, and the flexible external gear is bent into an elliptical shape by the wave generator, and external teeth located at both ends of the elliptical long axis direction. The portion meshes with a corresponding internal tooth portion in the internal gear. The wave generator is connected to the motor rotating shaft 5, and when the wave generator rotates, the meshing position of both gears moves in the circumferential direction, and relative rotation according to the difference in the number of teeth of both gears is generated between both gears. To do. In general, a rigid internal gear is fixed, and reduced speed rotation is taken out from an output shaft 8 attached to a flexible external gear.
[0016]
Next, the drive control device 3 that drives and controls the actuator 2 configured as described above receives the detection signal from the encoder 7 via the interface 21, and based on the detection signal and a position command signal supplied from a host device. A feedback control unit 22 that feedback-controls the motor 4 of the actuator 2 is provided. In addition, the drive control device 3 of this example includes a reading unit 23 that reads the reduction gear initial setting information 15 held in the storage unit 14 of the encoder 7 via the interface 21, and an initial setting that is read when the power is turned on. And an initial setting unit 24 that performs initial settings such as a maximum current value for motor driving, a rated current value, and various gains for position feedback control based on the information 15.
[0017]
In the servomotor system 1 with a speed reducer of this example configured in this way, information 15 about the speed reducer is transmitted from the encoder 7 side to the drive control device 3 when the power is turned on, and the drive control device 3 based on the information 15. Initial setting operation is performed. Therefore, in the system of this example, even if the speed reducer 6 incorporated on the actuator 2 side is changed, the operator performs an input operation or the like for changing the initial setting in accordance with the change on the drive control device 3 side. There is no need.
[0018]
In addition, information on the positioning error of the actuator 2 caused by the angle transmission error inherent to each of the reduction gears 6 is also stored and held on the encoder 7 side, and a position detection signal from which the positioning error has been eliminated is driven from the encoder 7. It is output to the control device 3. Therefore, a positioning error caused by an angle transmission error unique to each reduction gear can be eliminated by using a general-purpose drive control device 3.
[0019]
(Error correction data)
Here, the error correction data 16 of this example is created as follows. First, the positioning error of the motor rotation shaft 5 in the actuator 2 is compressed to one reduction ratio of the reduction gear by the reduction of the wave gear reduction gear 6 connected thereto. For example, when the speed ratio of the wave gear reducer 6 is 50 or 100, the positioning error of the motor itself is compressed to 1/50 or 1/100. Therefore, since the positioning error of the actuator 2 is mainly caused by the angle transmission error of the wave gear reducer 6, the one-way positioning accuracy of the actuator 2 is determined by the angle transmission error of the wave gear reducer 6.
[0020]
One-way positioning accuracy means positioning one after another in a certain rotational direction, and at each position, the difference between the angle actually rotated from the reference position and the angle to be rotated is obtained, and during these one rotation Represents the maximum value at.
[0021]
In this example, the one-way positioning accuracy of the actuator 2, that is, the positioning error of the actuator is measured for one rotation of the actuator output shaft 8 based on the absolute position of the motor rotating shaft 5. For example, when the speed ratio of the wave gear reducer 6 is 1/50, when the motor rotation shaft 5 rotates 50 times, the output shaft 8 rotates once.
[0022]
This positioning error is measured, for example, every time the motor rotating shaft 5 rotates 3 ° using a general encoder. In this case, the measurement point is 120 points (360 ° / 3 °) for the motor rotation shaft 5 and 120 points × (speed ratio) for the actuator output shaft 8.
[0023]
The correction data may be measured for one rotation of the actuator output shaft 8. In this case, the absolute position of the output shaft is detected by some method, and correction data is measured using the absolute position as a reference.
[0024]
Next, error data at each measurement point, for example, error data at 120 locations is averaged, and error correction data 16 for one rotation of the motor rotating shaft 5 is created.
[0025]
The format of the created error correction data 16 can be the number of correction pulses for error correction for each rotation angle position in one rotation of the motor rotating shaft 5. For example, it is possible to use a correspondence table in which the number of correction pulses measured every 3 ° as described above is assigned to the rotational position of the motor rotation shaft 5 every 3 °.
[0026]
Instead of this, error correction data for one rotation of the motor rotating shaft 5 is expanded into a Fourier series to obtain an approximate curve, and each coefficient of the Fourier series representing the approximate curve is stored and held as error correction data 16. Good. In this case, in the initialization process after the drive power supply of the drive control device 3 is turned on, the correction data is calculated by applying the stored coefficient to the approximate expression and the correction pulse data string is created. Good.
[0027]
【The invention's effect】
As described above, in the present invention, information on the speed reducer is stored and held on the encoder side of the servo motor with a speed reducer, and this is read into the drive control device side to perform various initial settings for motor control. To do. Accordingly, a general-purpose drive control device can be used, and even if the speed reducer model is changed, the operator does not need to perform setting change processing.
[0028]
In addition, since error correction data for eliminating positioning errors due to the angle transmission error of the reducer is stored and held in the encoder and positioning control is performed based on this, accurate positioning can be realized. In particular, since such data is held on the encoder side and read on the drive control device side, the drive control device can be widely used.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram of a servo motor system with a reduction gear to which the present invention is applied.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Servo motor system with a reduction gear 2 Actuator 3 Drive control apparatus 4 Motor 5 Motor rotating shaft 6 Reduction gear 7 Encoder 8 Actuator output shaft 11 Detection part 12 Signal processing part 13 Interface 14 Storage part 15 Reduction gear initial setting information 16 Error correction Data 18 Information output unit 19 Correction unit 21 Interface 22 Feedback control unit 23 Reading unit 24 Initial setting unit

Claims (2)

In a servomotor with a speed reducer comprising a motor (4), an encoder (7) for detecting the rotational position of the motor rotating shaft (5), and a speed reducer (6) connected to the motor rotating shaft (5) ,
The speed reducer (6) is a wave gear speed reducer;
The encoder (7)
A detection unit (11) comprising a rotary disk with slits and an optical detection element attached to the motor rotation shaft (5);
A signal processing unit (12) for encoding a detection signal output from the detection unit (11) and converting it into a pulse signal representing a rotational position;
An interface (13) for transmitting the encode signal generated by the signal processing unit (12) to a drive control device (3) for driving and controlling the motor (4);
Initial setting information (15) regarding the speed reducer including the model, model number, and speed ratio of the speed reducer (6), and error correction data for compensating for positioning errors caused by the angle transmission error of the speed reducer (6) A storage unit (14) in which (16) is stored and held in advance;
Positioning caused by an angle transmission error of the speed reducer (6) by adding a correction pulse number to the encode signal output from the signal processing unit (12) based on the error correction data (16). A correction unit (19) that removes an error and outputs the corrected encoded signal obtained thereby to the drive control device (3) side through the interface (13);
When the power is turned on and when a transfer request is received from the drive control device (3) side, the initial setting information (15) related to the speed reducer (6) stored in the storage unit (14) is stored in the storage unit (14). An information output unit (18) for outputting to the drive control device (3) side through an interface (13),
The servo motor with a speed reducer, wherein the error correction data (16) is angle transmission error correction data for each rotation angle position of the speed reducer input shaft detected by the encoder (7). A drive control device (3) for driving and controlling the servo motor with a reduction gear according to claim 1,
A feedback control unit that receives the corrected encoded signal from the encoder (7) and feedback-controls the motor (4) based on the corrected encoded signal and a position command signal supplied from a host device. 22)
A reading unit (23) for reading the initial setting information (15) held in the storage unit (14) of the encoder (7);
An initial setting unit (24) for performing initial setting of a maximum current value and a rated current value for driving the motor and a gain for position feedback control based on the read initial setting information (15) when the power is turned on. A drive control device (3) for a servo motor with a speed reducer, characterized by comprising:

Images