CN114079411A

CN114079411A - Online automatic identification method for servo motor

Info

Publication number: CN114079411A
Application number: CN202111309337.7A
Authority: CN
Inventors: 江建斌; 宋祥
Original assignee: Minli Intelligent Technology Zhejiang Co ltd
Current assignee: Minli Intelligent Technology Zhejiang Co ltd
Priority date: 2021-11-06
Filing date: 2021-11-06
Publication date: 2022-02-22

Abstract

The invention discloses a method for automatically identifying a servo motor on line, which belongs to the technical field of servo motor calibration systems and solves the problems of complex steps, complex operation and higher cost of servo motor identification and parameter calibration of enterprises.

Description

Online automatic identification method for servo motor

Technical Field

The invention relates to the field of servo motor systems, in particular to an online automatic identification method for a servo motor.

Background

A servo motor: the servo motor is a motor which is controlled by a servo driver to realize accurate control on the position, the speed and the torque of a relevant machine, and the servo motor is mainly a Permanent Magnet Synchronous Motor (PMSM) and is provided with position encoders of different types and resolutions according to requirements.

A position encoder: the sensor is used for tracking the angle or position of a motor rotor, and is divided into photoelectric, magnetoelectric, rotary transformer, sine and cosine according to a sensing technology, an incremental type, an absolute type, an analog type and an incremental type according to signal types, and is divided into a multi-wire type, a wire-saving type and a bus type according to a wiring mode, wherein the bus type is divided into multiple types such as NRZ, Endat, bis, SSI and the like according to a bus data protocol.

The servo motor has wide application scenes, different application requirements, different motor design schemes and manufacturing processes and different types of position encoders, so that the servo motors are very various, the first calibration work of the servo motor and a servo driver with a new model is finished in a factory laboratory at present, and the main reason is that a servo motor current loop is a bottommost loop which is a basis for the excellent performance of an outer-layer speed loop and a position loop, so that the reasonable setting of current loop parameters is very important. The current loop control parameters are directly related to an internal model of the servo motor, current loop PI parameters need to be set according to electrical parameters (stator inductance, stator resistance, back electromotive force, pole pair number, rated current, peak current and the like) of the servo motor, in addition, the type and precision of a position encoder, the zero offset of the electric angle, the rotational inertia of a rotor and the like are related factors for realizing parameter transmission between the current loop and a speed loop, detection and calibration are also needed in a factory, the processes need to be carried out in a laboratory environment, a professional engineer is driven by the motor to repeatedly try and adjust by means of a professional testing instrument and a simulation debugging system, and the whole adaptation process is time-consuming and labor-consuming. When the servo driver is applied to a field, the servo driver only can use the type of the calibrated servo motor, if the servo driver is replaced by the servo motor which is not matched on the field, the servo driver cannot normally and reliably operate at all, even if the servo driver can rotate reluctantly, the control effect is greatly reduced, the close coupling relation between the servo driver and the servo motor increases the difficulty of the manufacturing link and inventory management of the servo driver, and after-sale maintenance is greatly influenced, for example, even if the original servo motor of a client is damaged and stops, even if the original servo motor of the client is similar to the existing servo motor, the servo driver cannot be replaced in time as long as the original servo motor of the client is not calibrated, and the satisfaction degree of the client is reduced.

Disclosure of Invention

Aiming at the defects of the prior art, the invention at least solves the technical problems in the related technology to a certain extent, the calibration of the current loop control parameters of the servo motor with a new model is completed by professional technicians by means of special instruments and equipment in a factory laboratory environment, and cannot be replaced and used in an application field in real time, so that the flexible configuration and after-sale maintenance of a servo driving system are greatly limited, and the current loop online identification method of the servo motor can well solve the problems of field adaptation and after-sale maintenance of the servo motor.

In order to solve the technical problems, the technical scheme of the invention is as follows: an on-line automatic identification method of a servo motor, which arranges an on-line automatic identification device in a servo driver and is characterized in that: the on-line automatic identification device starts to operate after receiving a starting command, and the method comprises the following steps:

step 1: acquiring the motor class input by an external user or the manufacturing parameters which can be selectively input, selecting a corresponding encoder identification model according to the motor class and the manufacturing parameters, and identifying and correcting the servo motor encoder;

step 2: identifying the phase sequence and the pole pair number of the servo motor;

and step 3: current loop PI parameters are intelligently adjusted;

and 4, step 4: and calibrating the rotational inertia of the servo motor and the gain of the speed loop.

Preferably, the step 1 includes dividing the position encoder into a photoelectric type, a magnetoelectric type, a rotary transformer and a sine-cosine type according to a sensing technology, an incremental type, an absolute type and an analog type according to a signal type, a multi-wire type, a wire-saving type and a bus type according to a wiring mode, classifying the identification models of the encoders into NRZ, Endat, bis and SSI types according to a bus data protocol to form corresponding encoder identification modules, determining a specific encoder type according to input information, and calling the corresponding encoder identification modules.

Preferably, step 2 includes controlling the electric field scalar Vd, Vq value, electrical angle and step length by open loop control, where the electric field scalar Vd is K, Vq-0, the electrical angle is set to zero and stays for 2s, and the current encoder value is recorded; the values of electric field scalars Vd and Vq are unchanged, the step length of the electric angle is increased by 60 degrees and stays for 2s, and the current encoder value is recorded until the full 2-turn operation is completed;

and evaluating and checking whether the resolution, the pole pair number, the electric angle zero offset and the power phase sequence of the encoder are correct, if not, closing the PWM, displaying an alarm number, storing an alarm record, ending, and if correct, closing the PWM to record the precision, the pole pair number, the power phase sequence and the electric angle zero offset information of the encoder.

Preferably, step 3 includes testing inductance and resistance of the motor according to basic parameters, general parameters of the motor and manufacturing parameters of the motor, then setting initial values and maximum values of identification of PI parameters of the current loop, Iq _ ref test standard values, initial points of Kp and Ki, and adjustment step length parameters of Kp and Ki respectively, ensuring that the optimal PI parameters are within the interval, identifying and measuring Iq _ ref reasonably set according to rated current, giving step input Iq _ ref, observing a response curve of Iq _ fbd, continuously adjusting Kp and Ki of the current loop, and performing statistical analysis on the optimal Kp parameters and Ki parameters.

Preferably, step 3 includes starting the Iq response attempt, recording the Iq response curve, determining whether the Iq _ fdb overshoot reaches an upper limit, if so, statistically analyzing an optimal Kp parameter, if not, determining whether the Kp reaches the upper limit, if so, statistically analyzing the optimal Kp parameter, otherwise, increasing the step size of the Kp parameter, and entering the Iq response attempt again until the Iq _ fdb overshoot or the Kp reaches the upper limit, and statistically analyzing the optimal Kp parameter.

Preferably, step 3 includes starting the Iq response attempt, recording the Iq response curve, determining whether the Iq _ fdb overshoot reaches an upper limit, if so, statistically analyzing an optimal Ki parameter, otherwise, determining whether Ki reaches an upper limit, if so, statistically analyzing an optimal Ki parameter, and if not, increasing the step size of the Ki parameter, entering the Iq response attempt again until the Iq _ fdb overshoot or the Ki reaches the upper limit, and statistically analyzing the optimal Ki parameter.

Preferably, the step 4 of calibrating the rotational inertia and the speed loop gain comprises: during calibration, the calculation is carried out by back-stepping according to the time width of the Iq _ fdb step response motor rotor speed from zero to the preset speed, and the reference speed loop unit gains Knp0 and Kni0 are obtained according to the time constant, so that the rotational inertia and the speed loop gain are calibrated.

Compared with the background technology, the technical effects of the invention are mainly reflected in the following aspects: the core invention point of the invention is that through deep analysis of principle models of each component in the servo motor, an automatic identification test calibration method is adopted, and the relatively complex motor calibration process which can be operated by professional technicians is simplified into one-key automatic identification calibration. The whole identification process does not need manual intervention, and the identification time is finished within 1-3 minutes.

Drawings

FIG. 1 is a first part of a flowchart of a method according to an embodiment;

FIG. 2 is a second part of the flowchart of the method in the embodiment;

FIG. 3 is a third part of the flowchart of the method in the embodiment.

Detailed Description

The following detailed description of the embodiments of the present invention is provided in order to make the technical solution of the present invention easier to understand and understand.

Example (b):

referring to fig. 1, 2 and 3, an online automatic identification method for a servo motor, in which an online automatic identification device is built in a servo driver, is characterized in that: the on-line automatic identification device starts to operate after receiving a starting command, and the method comprises the following steps:

step 1: acquiring the motor class input by an external user or the manufacturing parameters which can be selectively input, selecting a corresponding encoder identification model according to the motor class and the manufacturing parameters, and identifying and correcting the servo motor encoder; the position encoder is divided into photoelectric, magnetoelectric, rotary transformer and sine and cosine according to sensing technology, is divided into increment type, absolute type and analog type according to signal types, is divided into multi-wire type, wire-saving type and bus type according to a wiring mode, the bus type is divided into NRZ type, Endat type, bis type and SSI type according to a bus data protocol, identification models of the encoders of the types are classified to form corresponding encoder identification modules, specific encoder types are determined according to input information, and the corresponding encoder identification modules are called.

The servo motor encoder is a sensor for tracking the angle or position of a motor rotor, is a core component in a servo motor, and the resolution and installation angle deviation of the encoder are closely related to the performance of the motor, so that the first process of online identification of the servo motor is to identify and correct the motor position encoder.

Step 2: and identifying the phase sequence and the pole pair number of the servo motor. The values, the electrical angles and the step sizes of the electric field scalars Vd and Vq are controlled by open loop control, wherein the electric field scalar Vd is K, Vq is 0, and K is a constant. Setting the electrical angle to zero and staying for 2s, and recording the current encoder value; the values of electric field scalars Vd and Vq are unchanged, the step length of the electric angle is increased by 60 degrees and stays for 2s, and the current encoder value is recorded until the full 2-turn operation is completed;

and evaluating and checking whether the resolution, the pole pair number, the electric angle zero offset and the power phase sequence of the encoder are correct, if not, closing PWM (pulse width modulation), displaying an alarm number, storing an alarm record, ending, and if so, closing the PWM and recording the information of the precision, the pole pair number, the power phase sequence and the electric angle zero offset of the encoder.

The power line phase sequence and the pole pair number of the servo motors of different manufacturers may be different, even the power lines and the pole pair numbers of the servo motors of different models of the same manufacturer may be different, and the difference cannot be distinguished by naked eyes. Therefore, through the step 2, the identification of the phase sequence and the pole pair number of the servo motor is completed. Scalar Vd and Vq of the motor are set through open loop, the motor rotates in a preset electrical angle direction, and the rotating direction fed back by a motor position encoder is observed to judge whether the phase sequence of the power line is positive or negative. The discrimination principle of the number of pole pairs of the motor is the same, the open loop sets the rotation angle or the number of turns of the servo motor, and the actual movement angle or the number of turns of the motor is observed for discrimination. The identification of the phase sequence and the number of pole pairs must be possible after the encoder identification.

And step 3: and intelligently adjusting the PI parameter of the current loop. The performance of a servo motor is directly related to the PI parameter of a current loop, the reasonable setting of the current loop parameter is very important, the winding inductance L, the resistance R, the counter electromotive force, the overload multiplying power and the pole pair number of different motors are difficult to be consistent, even if different materials are adopted in the same design scheme, such as iron cores, enameled wires, magnetic steel sheets and the like, the inductance L, the resistance R and the counter electromotive force E of the motors, the reference of the PI parameter is derived from the key parameters, the transfer function relation among the key parameters is researched, the inductance and the resistance of the motors are tested according to the basic parameters, the large-class parameters of the motors and the manufacturing parameters of the motors, then the initial value, the maximum value, the Iq _ ref (test standard value), the initial points of Kp and Ki and the adjustment step length parameters of the Kp and Ki of the PI parameter identification of the current loop are respectively set, and the optimal PI parameter is ensured in the interval, and (3) reasonably setting Iq _ ref according to rated current by identification and measurement, giving a step input Iq _ ref, observing a response curve of Iq _ fbd, continuously adjusting current loops Kp and Ki, and carrying out statistical analysis on an optimal Kp parameter and an optimal Ki parameter.

Starting the Iq response attempt, recording the Iq response curve, judging whether the Iq _ fdb overshoot reaches the upper limit, if so, statistically analyzing an optimal Kp parameter, otherwise, judging whether the Kp reaches the upper limit, if so, statistically analyzing an optimal Kp parameter, otherwise, increasing the step length of the Kp parameter, and entering the Iq response attempt again until the Iq _ fdb overshoot or the Kp reaches the upper limit, and statistically analyzing the optimal Kp parameter.

Starting the Iq response attempt, recording the Iq response curve, judging whether the Iq _ fdb overshoot reaches the upper limit, if so, statistically analyzing an optimal Ki parameter, otherwise, judging whether the Ki reaches the upper limit, if so, statistically analyzing the optimal Ki parameter, and if not, increasing the step length of the Ki parameter, entering the Iq response attempt again until the Iq _ fdb overshoot or the Ki reaches the upper limit, and statistically analyzing the optimal Ki parameter.

And 4, step 4: and calibrating the rotational inertia of the servo motor and the gain of the speed loop. The calibration of the moment of inertia and the gain of the speed loop comprises the following steps: during calibration, the calculation is carried out by back-stepping according to the time width of the Iq _ fdb step response motor rotor speed from zero to the preset speed, and the reference current loop unit gains Knp0 and Kni0 are obtained according to the time constant, so that the rotational inertia and the speed loop gain are calibrated.

The optical axis moment of inertia of the servo motor is related to the unity gain of the velocity rings Knp0, Kni 0. The servo motors are often connected to other mechanical transmission mechanisms in application fields, the mechanical structures can be converted into rotational inertia ratios of several times or dozens of times, the rotational inertia ratios are different, the Knp and Kni gains of the speed rings are required to be adjusted correspondingly, the rotational inertia ratios can be simply equivalent to Knp Jr Knp0, Kni Jr Kni0, Jr is the rotational inertia ratio calculated by all the machines connected to the servo motors, and Knp0 and Kni0 are speed ring unit gains. The unit gain is a basic parameter of the actual field speed loop and gain, too large deviation cannot exist, and the parameter self-adaption of the speed loop cannot achieve the perfect control effect.

The method is used for automatically identifying all the electrical parameters of the servo motor, such as the pole pair number, the encoder resolution, the mechanical zero electrical angle deviation value, the current loop PI parameter, the speed loop PI unit gain and the like, within a few minutes only by correctly connecting the drive controller and the servo motor and providing basic electrical parameters, no matter which servo motor is manufactured and which type of position sensor is configured.

Before a user prepares to start the on-line identification function of the current loop, firstly, the driver is required to be determined to be in a non-enabled state, then whether the identified servo motor wiring (a power line and a position encoder line) is correct is checked, after the correctness is confirmed, the motor category can be selected or basic motor electrical parameters can be input through a driver panel menu, the on-line identification function is activated, the function is in an automatic operation state once the function is started, the whole process does not need to be interfered, the parameters are automatically stored and taken effect after the identification is successfully completed, the adaptation effect is equivalent to that of a professional, the detection efficiency is obviously superior to that of the traditional calibration method, and the user can confirm the identification effect by observing a current loop response curve through upper computer software.

The functional method can be used for automatically calibrating the newly added servo motor instead of professionals in a factory, can also be used for calibrating and correcting when a client replaces an unregistered servo motor on site, and has strong operability.

At present, when a new motor supplier is added or raw materials are replaced, the calibration work of the current loop of the servo motor is repeated in order to achieve the best performance. As mentioned above, the current loop calibration of the servo motor is performed by professional technicians in a laboratory environment with the aid of special detection instruments and simulation equipment, and enterprises pay a lot of labor and time costs. On the other hand, because of the strong coupling relationship between the servo driver and the servo motor, if the servo driver or the servo motor is not operated in a customer application field, the product of the original model must be replaced, once the original model is out of stock or stops production, the whole set of the original model must be replaced to continue working, the after-sale maintenance cost is high, and great resource waste is caused. The invention aims to provide a brand-new online automatic identification method for the servo motor, which has the characteristics of rapidness, accuracy and effectiveness, has the identification effect equivalent to that of professional technicians, can obviously improve the detection calibration and after-sale service efficiency of servo motor products, and controls the operation cost of enterprises.

The above are only typical examples of the present invention, and besides, the present invention may have other embodiments, and all the technical solutions formed by equivalent substitutions or equivalent changes are within the scope of the present invention as claimed.

Claims

1. An on-line automatic identification method of a servo motor, which arranges an on-line automatic identification device in a servo driver and is characterized in that: the on-line automatic identification device starts to operate after receiving a starting command, and the method comprises the following steps:

and step 3: current loop PI parameters are intelligently adjusted;

2. The method for on-line automatic identification of the servo motor as claimed in claim 1, wherein: the method comprises the following steps of 1, dividing a position encoder into a photoelectric type, a magnetoelectric type, a rotary transformer and a sine-cosine type according to a sensing technology, dividing the position encoder into an increment type, an absolute type and an analog type according to a signal type, dividing the position encoder into a multi-wire type, a wire-saving type and a bus type according to a wiring mode, dividing the bus type into an NRZ type, an Endat type, a bis type and an SSI type according to a bus data protocol, classifying identification models of the encoders of the types to form corresponding encoder identification modules, determining a specific encoder type according to input information and calling the corresponding encoder identification modules.

3. The method for on-line automatic identification of the servo motor as claimed in claim 2, wherein: step 2, controlling the values of electric field scalars Vd and Vq, the electrical angle and the step length in an open-loop control mode, wherein the electric field scalars Vd are K, Vq and 0, the electrical angle is set to zero and stays for 2s, and the current encoder value is recorded; the values of electric field scalars Vd and Vq are unchanged, the step length of the electric angle is increased by 60 degrees and stays for 2s, and the current encoder value is recorded until the full 2-turn operation is completed;

4. A method for on-line automatic identification of servo motor as claimed in claim 1, 2 or 3, wherein: and step 3, testing the inductance and the resistance of the motor according to basic parameters, general parameters and manufacturing parameters of the motor, then respectively setting an initial value and a maximum value of the identification of the PI parameter of the current loop, an Iq _ ref test standard value, starting points of Kp and Ki and adjustment step length parameters of Kp and Ki, ensuring that the optimal PI parameter is in the interval, reasonably setting Iq _ ref according to rated current in identification measurement, giving step input Iq _ ref, observing a response curve of Iq _ fbd, continuously adjusting the Kp and Ki of the current loop, and carrying out statistical analysis on the optimal Kp parameter and the Ki parameter.

5. The method for on-line automatic identification of the servo motor as claimed in claim 4, wherein: and 3, starting the Iq response attempt, recording the Iq response curve, judging whether the Iq _ fdb overshoot reaches an upper limit, if so, statistically analyzing an optimal Kp parameter, otherwise, judging whether the Kp reaches the upper limit, if so, statistically analyzing the optimal Kp parameter, otherwise, increasing the step length of the Kp parameter, entering the Iq response attempt again, and until the Iq _ fdb overshoot or the Kp reaches the upper limit, statistically analyzing the optimal Kp parameter.

6. The method for on-line automatic identification of the servo motor as claimed in claim 4, wherein: and 3, starting the Iq response attempt, recording the Iq response curve, judging whether the Iq _ fdb overshoot reaches an upper limit, if so, statistically analyzing an optimal Ki parameter, otherwise, judging whether Ki reaches an upper limit, if so, statistically analyzing an optimal Ki parameter, otherwise, increasing the step length of the Ki parameter, and entering the Iq response attempt again until the Iq _ fdb overshoot or the Ki reaches the upper limit, and statistically analyzing the optimal Ki parameter.

7. The method for on-line automatic identification of the servo motor as claimed in claim 1, wherein: the calibration of the rotational inertia and the velocity loop gain in the step 4 comprises the following steps: during calibration, the calculation is carried out by back-stepping according to the time width of the Iq _ fdb step response motor rotor speed from zero to the preset speed, and the reference speed loop unit gains Knp0 and Kni0 are obtained according to the time constant, so that the rotational inertia and the speed loop gain are calibrated.