JPH07303390A - Servomotor system - Google Patents

Abstract

PURPOSE:To easily manage the error data characteristic to a servomotor and a motor sensor of each motor unit by storing in a data memory the error data and motor parameters, which are characteristic to the servomotor and the motor sensor of each motor unit. CONSTITUTION:The error data and motor parameters, which are characteristic to a servomotor 3 and a motor sensor 5 of a motor unit 1, are stored in a data memory 6 which is built in the motor unit 1. Based on the error data and the motor parameters stored in the data memory 6, a servodriver 2 corrects a detected error characteristic to the motor sensor 5 and the pulsation of a generated torque characteristic to the servomotor 3 by means of a sensor error correcting means 22 and a torque error correcting means 23. Then, based on the correction result and the motor parameters, the torque and the speed are controlled and the motor is protected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo motor system used for various automatic control equipment including NC machine tools and various robots.

[0002]

2. Description of the Related Art A servo motor system includes a motor unit which is integrated with a servo motor and a motor sensor for detecting the angle and speed of the servo motor, and the servo motor based on a detection signal fed back from the motor sensor. It is needless to say that it is constituted by a servo driver for controlling the driving of the motor, and very high driving accuracy is required. That is, a servo motor is required to have high stability of generated torque, and a motor sensor integrated with the servo motor is required to have high detection accuracy.

However, in a servo motor, for example, a permanent magnet type AC servo motor, due to magnetizing conditions of the magnets, assembling conditions of the armature, etc., the generated torque within one rotation is inherently pulsating, that is, specific to the expected value. There is an error of. Further, a motor sensor, for example, a reluctance synchro-resolver type angle sensor also has an error in a detected value within one rotation depending on an assembly condition to a motor shaft and the like. If the servo driver drives and controls the servo motor on the basis of the detection signal with this error, naturally, the pulsation of the torque and speed of the servo motor and the deterioration of the positioning accuracy will be caused.

Therefore, conventionally, in order to realize a high-precision servo motor system, high-precision parts have been adopted, the motor unit has been assembled with high precision, and multiple feedback to the servo driver has been set.

Further, as in the servo control method disclosed in Japanese Patent Application Laid-Open No. 4-60704, various motor parameters necessary for control are stored in advance in the storage means in the control device for each type of output of the servo motor. A method has also been proposed in which the parameters are stored and automatically read from the storage means according to the type of the servomotor to be controlled, and the drive is controlled.

[0006]

However, the use of high-precision parts, high-accuracy assembly of the motor unit, setting of multiple feedback to the servo driver, and the like, as described above, cause a great increase in cost. become.

Further, like the servo control method described above, even if various parameters necessary for control are automatically read and controlled according to the type of the servo motor, the pulsation of the torque unique to each servo motor, Further, since the detection error peculiar to each motor sensor integrated with the servo motor is not taken into consideration, it is difficult to greatly improve the accuracy of the servo motor system.

For each servo motor and motor sensor of each motor unit that is mass-produced, the error data peculiar to each is managed together with various parameters according to the type of servo motor and set in the servo driver. This is a complicated task that is almost impossible, and if the wrong data is set, the servo motor and servo driver may be damaged.

The present invention has been proposed to solve the above-mentioned problems, and it is possible to easily manage error data unique to each servo motor and motor sensor of each motor unit. It is an object of the present invention to provide a servo motor system that is easy to handle, highly accurate, and inexpensive.

[0010]

In order to achieve the above object, in the servo motor system according to the present invention, in the motor unit (1), torque error data relating to the pulsation of the generated torque peculiar to the servo motor (3) is stored. , Sensor error data relating to a detection error peculiar to the motor sensor (5), and motor parameters necessary for controlling the servo motor (3),
A non-volatile data memory (6) storing therein, and a servo driver (2) for reading data of each error and motor parameter stored in the data memory (6) in the motor unit (1). Means (21), and a sensor error correction means (22) for correcting a detection error specific to the motor sensor (5) based on the sensor error data read by the data reading means (21),
Based on the torque error data read by the data reading means (21) and the detection signal of the motor sensor (5) corrected by the sensor error correction means (22), the pulsation of the generated torque peculiar to the servo motor (3) is determined. A torque error correction means (23) for correction is incorporated, and the servo driver (2) corrects the correction results of the sensor error correction means (22) and the torque error correction means (23) and the data reading means (21). ) Is configured to drive and control the servo motor (3) based on the motor parameters read by the above.

[0011]

In the servo motor system having the above structure, the data memory (6) incorporated in the motor unit (1).
Of the servo motor (3) of the motor unit (1), the error data peculiar to each of the servo motor (3) and the motor sensor (5) and the motor parameter are stored. ) And the motor sensor (5), it is possible to easily manage their own error data.

The servo driver (2) uses the sensor error correction means (22) and the torque error correction means (23) to detect the detection error specific to the motor sensor (5) and the pulsation of the generated torque specific to the servo motor (3). Are corrected, and torque control, speed control, and motor protection are performed based on the correction results and the motor parameters. Therefore, the servo motor (3) of each motor unit (1)
Can be appropriately drive-controlled with extremely high accuracy. Moreover, the accuracy of the servo motor (3) and the motor sensor (5) itself, and the assembly accuracy of the motor unit (1) are also corrected during drive control, so that particularly high accuracy is not required, resulting in a large cost. It is possible to lower it.

The reference numerals in the above parentheses are for the purpose of comparison with the drawings and do not limit the structure of the present invention.

[0014]

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

FIG. 1 is a block diagram showing the main configuration of a servo motor system according to the present invention.

As shown in the figure, this servo motor system is
It is composed of a motor unit 1 and a servo driver 2. Inside the motor unit 1, a servo motor (here, a permanent magnet type three-phase AC servo motor) 3 and the angle and speed of the servo motor 3 are detected. The motor sensor 5 is provided in an integrated state, and a non-volatile data memory 6 is incorporated. The data memory 6 has torque error data relating to pulsation of the generated torque peculiar to the servo motor 3 within one rotation, sensor error data relating to detection error peculiar to the motor sensor 3, and data measured as described later. It stores various motor parameters such as maximum current, maximum rotation speed, torque constant, winding impedance, number of motor poles, thermal time constant, etc. necessary for controlling the servo motor 3, and a clock for synchronizing data reading. And a command for controlling data storage are input from a control device (not shown).

As the motor sensor 5, for example, a reluctance synchro-resolver type angle sensor as shown in the schematic diagram of FIG. 2 is used. In this motor sensor 5, yokes 51u, 51v, 51 for three phases are provided.
A rotor 52 is arranged in a fixed core 51 having w in a state of being eccentric with respect to the shaft 3a of the servo motor 3, and each yoke 51u, 51v, 5 is rotated with rotation.
The distance from 1w is changing. Therefore, the inductances of the windings 53u, 53v, 53w wound around the yokes 51u, 51v, 51w respectively change according to the angle of the rotor 52.

The three-phase windings 53u, 53v, 5
An alternating current is supplied from the OSC (oscillator) 55 to 3w and is input to the electronic Scott circuit 56. The electronic Scott circuit 56 processes the inflowing current according to the inductance of the windings 53u, 53v, 53w of each phase, and detects the sin θ, cos θ analog voltages according to the rotation angle θ of the rotor 52. Output as a signal.

The error data relating to the detection error peculiar to the motor sensor 5 is stored in the data memory 6 as described above. Therefore, the detection accuracy of the motor sensor 5 does not need to be particularly high.

As the motor sensor 5, an angle sensor such as an optical or magnetic rotary encoder may be used in addition to the reluctance synchro resolver type.

On the other hand, the servo driver 2 has two adders 11 and 11 'and two PIDs as components necessary for torque control of a normal three-phase servomotor.
Arithmetic unit 12, 12 ', two-phase / three-phase converter 13, power amplifier 15, two armature current detectors 16, 16',
A three-phase / two-phase converter 17 and a sensor reader 19 are provided.

In these ordinary configurations, each PID calculator 12, 12 'is passed through each adder 11, 11'
A d-axis component (ineffective component, usually 0) and a q-axis component (effective component) are input as torque commands from a control device (not shown). Further, of the three-phase armature currents supplied from the power amplifier 15 to the servo motor 3, the two-phase armature currents are
When the armature current detectors 16 and 16 'detect,
The phase-to-two-phase converter 17 has a current component iq effective for generating torque.
And an invalid current component id. At that time, the three-phase / two-phase converter 17 reads the detection signal (sin) read by the sensor reader 19 and fed back from the motor sensor 5.
θ, cos θ), and converts the armature current into the above two current components iq, id.

Then, the adders 11 and 11 'calculate respective deviations from the current components iq and id and the d-axis component and the q-axis component of the torque command, and the respective PID calculators 1
2, 12 'perform proportional amplification, integral amplification, and differential amplification of the deviation. The two-phase / three-phase converter 13 converts the results of these PID calculations into three phases, and the power amplifier 15 amplifies the result to supply a current to the armature of the servomotor 3. The detection signal fed back from the motor sensor 5 which is read by the sensor reader 19 is also sent to a speed control unit (not shown) and used for speed control of the servo motor 3.

In the control loop having the above-mentioned normal configuration,
The pulsation of the generated torque peculiar to the servo motor 3 and the detection error peculiar to the motor sensor 5 affect the drive control.

Therefore, the servo driver 2 in the servo motor system according to the present invention reads the sensor error data, the torque error data, and the motor parameters stored in the data memory 6 in the motor unit 1 in addition to the above-mentioned normal configuration. Data reader (data reading means) 21
And a sensor error corrector (sensor error correction means) 22 for correcting a detection error specific to the motor sensor 5 based on the sensor error data read by the data reader 21, and a torque error read by the data reader 21. A torque error corrector (torque error correction means) 23 for correcting the pulsation of the generated torque unique to the servomotor 3 based on the data and the detection signal of the motor sensor 5 corrected by the sensor error corrector 22 is incorporated. There is. The sensor error corrector 22 includes a sensor reader 19 and a three-phase / two-phase converter 1
7, the torque error corrector 23 is
It is inserted between the two-phase converter 17 and each adder 11, 11 '.

In the servo driver 2 in which the data reader 21, the sensor error compensator 22, and the torque error compensator 23 are incorporated, at the time of start-up, the data reader 21 first reads each error from the data memory 6 in the motor unit 1. Read data and motor parameters. This data memory 6,
Regarding the data transmission method between the data readers 21, since the motor unit 1 and the servo driver 2 are often installed at a considerable distance from each other, they are transmitted serially in order to reduce the number of signal lines. Is preferred.

The sensor error corrector 22 stores the sensor error data received from the data reader 21 as a sensor reading value correction table, and the motor sensor 5 read by the sensor reader 19 based on the correction table.
Correct the detection signal of. Thereby, the detection error peculiar to the motor sensor 5 is corrected.

Further, the torque error corrector 23 stores the torque error data received from the data reader 21 as a torque error correction table, and the correction table and the motor sensor 5 corrected by the sensor error corrector 22. The three-phase / two-phase converter 17 based on the detection signal of
The two current components iq and id converted by are corrected. As a result, the pulsation of the generated torque peculiar to the servo motor 3 is corrected.

Further, each PID calculator 12, 12 'is
The motor parameter such as the winding impedance received from the data reader 21 is stored as a PID calculation coefficient, and the PID calculation is performed based on the coefficient. Other motor parameters such as maximum current and maximum rotation speed, which are motor protection constants, are sent to the speed control unit and used for motor protection.

As described above, in the servo motor system according to the present invention, the servo driver 2 is the motor unit 1
Based on each error data read from the internal data memory 6, the detection error peculiar to the motor sensor 5 and the servo motor 3 are detected.
The pulsation of the inherent generated torque is corrected, and torque control, speed control, motor protection, etc. are performed based on the correction results and various motor parameters read from the data memory 6. The servo motor 3 can be appropriately drive-controlled with extremely high accuracy. Moreover, the accuracy of the servo motor 3 and the motor sensor 5 itself, and the assembly accuracy of the motor unit 1 are also corrected at the time of drive control, so that particularly high accuracy is not required, and multiple feedback to the servo driver 2 is set. Etc. are not necessary, and the cost can be greatly reduced.

Further, the data memory 6 storing the error data specific to the motor sensor 5, the error data specific to the servomotor 3, and the motor parameters is provided in the motor unit 1.
Since the sensor 5 and the motor 3 are incorporated into the inside, the error data peculiar to each of the servo motor 3 and the motor sensor 5 of each motor unit 1 to be mass-produced are stored in various parameters according to the type of the servo motor 3. Can be easily managed with. Further, it is not necessary to set error data and various parameters specific to each motor unit 1 in the servo driver 2. That is, the motor unit 1 that is driven and controlled by one servo driver 2
Even if you replace the other motor unit of the same type, immediately
The new motor unit can be appropriately drive-controlled with extremely high accuracy.

Next, an example of a method of measuring error data specific to each motor unit 1 will be described.

As shown in the schematic diagram of FIG. 3, a servo motor 3 of the motor unit 1 to be measured includes a high-precision angle detector 71 such as a high-precision rotary encoder, and a flywheel 72 for absorbing speed ripple. , Drive motor 7
3 and 3 are connected in series.

Then, the drive motor 73 is rotated at a constant speed, and the reference detection signal output from the high precision angle detector 71 at that time, the counter electromotive voltage of each phase of the servo motor 3, and the detection signal of the motor sensor 5 are detected. Is input to the data processing device 75. The measurement data of these signals and the back electromotive force are accumulated in the data processing device 75 by the number corresponding to the resolution of the high precision angle detector 71.

The counter electromotive voltages U, V, W of the respective phases of the servo motor 3 are absolute values (U ² + V ² + W ² ) of the respective phases.
^Captured at ^1/2 . This is because this absolute value becomes a value proportional to the torque generated by the servo motor 3 when sine wave currents having different electrical angles of 120 degrees are applied to the respective phases.

By the way, generally, various errors that a rotating body has are represented by a function obtained by synthesizing a sine wave having a longest cycle having one cycle as one rotation and a sine wave having an integral multiple of the cycle, that is, a Fourier series. . For example, the rotation angle θ of the motor sensor 5
Let E (θ) be the sensor error function with respect to E (θ) = a ₁ · sin (θ + α ₁ ) + a ₂ · sin
(2θ + α ₂ ) + a ₃ · sin (3θ + α ₃ ) + ...
+ A _n · sin (nθ + α _n ).

The data processing device 75 uses the gains a ₁ , a ₂ , a ₃ of the respective terms of the sensor error function E (θ),
... and the phases α ₁ , α ₂ , α ₃ , ... are extracted from the measurement data by arithmetic processing and are written in the data memory 6 in the motor unit 1 for the next term corresponding to the required accuracy. . Further, with respect to the torque error function indicating the pulsation of the torque generated by the servo motor 3 within one rotation, the gain and the phase are extracted by the same process and written in the data memory 6.

In this way, the error data peculiar to the motor sensor 5 and the error data peculiar to the servomotor 3 are stored in the data memory 6 by using the gain and phase of each term of the error function represented by Fourier series. As a result, the memory capacity required for the data memory 6 can be significantly reduced as compared with the method of continuously storing all the measured error data. In other words, it is possible to use an inexpensive storage element having a small memory capacity, and it is possible to reduce the cost.

[0039]

As described above, in the servo motor system according to the present invention, the data memory is incorporated in the motor unit, and the error data unique to the servo motor and the motor sensor and the servo motor are incorporated in the data memory. Since various motor parameters required for control of the servo motor are stored, and the error data and motor parameters are read by the servo driver to drive and control the servo motor, the servo motor and motor sensor of each motor unit , Error data unique to each can be easily managed.

In order to correct the detection error peculiar to the motor sensor and the pulsation of the generated torque peculiar to the servo motor, and to perform torque control, speed control, and motor protection based on the correction results and the motor parameters. ,
The servomotors of the individual motor units can be appropriately drive-controlled with extremely high accuracy. In addition, the accuracy of the servo motor and the motor sensor itself, and the assembly accuracy of the motor unit are also corrected at the time of drive control, so that particularly high accuracy is not required, so that the cost can be greatly reduced.

That is, according to the present invention, it is possible to provide a servo motor system that is easy to handle, highly accurate, and inexpensive.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main configuration of a servo motor system according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing an example of a motor sensor.

FIG. 3 is a schematic configuration diagram illustrating an example of a method of measuring error data specific to a motor unit.

[Explanation of symbols]

 1 Motor Unit 2 Servo Driver 3 Servo Motor 5 Motor Sensor 6 Data Memory 21 Data Reader (Data Reading Means) 22 Sensor Error Corrector (Sensor Error Correcting Means) 23 Torque Error Corrector (Torque Error Correcting Means)

Claims (2)

[Claims] 1. A servomotor and an angle between the servomotor,
A servo motor system comprising: a motor unit that is integrated with a motor sensor that detects a speed; and a servo driver that drives and controls the servo motor based on a detection signal fed back from the motor sensor. A non-volatile nonvolatile memory that stores torque error data relating to pulsation of generated torque peculiar to the servo motor, sensor error data relating to detection error peculiar to the motor sensor, and motor parameters necessary for controlling the servo motor in the unit. A data memory is incorporated, and in the servo driver, data reading means for reading each error data and motor parameter stored in the data memory in the motor unit, and the sensor error data read by the data reading means Motorsen A pulsation of generated torque peculiar to the servo motor based on the sensor error correction means for correcting a peculiar detection error, the torque error data read by the data reading means, and the detection signal of the motor sensor corrected by the sensor error correction means. And a torque error correction means for correcting the servo motor, based on the correction result of the sensor error correction means and the torque error correction means, and the motor parameter read by the data reading means. A servo motor system characterized by drive control. 2. The data memory in the motor unit stores each of the error data by using a gain and a phase of each term of an error function represented by a Fourier series. Servo motor system.