A calibration system and method for open-loop self-calibration of a motor

Abstract

The present application relates to the field of encoders, and in particular to a calibration system and method for open-loop self-calibration of a motor, the system comprising an angle sensor and a controller, the angle sensor being used to detect the rotation angle of the motor, wherein the angle sensor comprises an angle correction module for outputting a real-time angle after correcting the rotation angle according to an angle correction parameter, and the angle correction module having an angle correction parameter self-calibration function, so as to self-calibrate the angle correction parameter in response to a calibration signal when the motor is in uniform rotation; the controller is configured to obtain the operating physical parameters of the motor, generate a drive signal according to the operating physical parameters, and send the drive signal to a driver, wherein the operating physical parameters can reflect the operating conditions of the motor. The present application can start and complete the self-calibration of the angle correction parameters without the need to install or remove additional equipment such as a reference encoder or a host computer.

Description

Technical Field

[0001] The present application relates to the field of encoders, and in particular to a calibration system and method for open-loop self-calibration of a motor. Background Art

[0002] Angle sensors (encoders) play a key role in control systems, but they generally have nonlinear errors. These errors affect the stability of the system and usually appear as periodic fluctuations in speed.

[0003] Nonlinear error refers to the error caused by the nonlinear relationship between the encoder measurement output and the actual physical quantity. Nonlinear error occurs when the relationship between the encoder output and the actual physical quantity is not a simple linear relationship. This error is usually caused by some factors in the design, manufacturing or installation process of the encoder, such as the nonlinear characteristics of the optical system, magnetic system or mechanical structure.

[0004] The relationship between the encoder output angle and the actual angle is not a simple linear relationship and cannot be expressed by a function. It is necessary to create a lookup table to record some key reference points and their angle correction parameters to map the encoder output to the actual position or angle. The angle between key reference points can be fitted to the nonlinear output of the encoder using a polynomial function in a local range. By finding an appropriate polynomial fit, nonlinear errors can be reduced over the entire measurement range. The order of the polynomial fit can be selected according to the specific situation.

[0005] When the angle correction parameters need to be calibrated, a reference encoder (such as an optical encoder) can be used for calibration. This method is called "Torching".

[0006] refer to Figure 1 , Figure 1 The following is a block diagram of a system that implements the "drag-and-drop" method to calibrate a motor. The basic principle of drag-and-drop is to superimpose an additional reference encoder on the actual output of the encoder to be calibrated. The purpose of this is to measure the actual output of the encoder to be calibrated and compare it with the accurate output of the reference encoder.

[0007] exist Figure 1In the system block diagram shown, the calibration system includes a motor, a driver for driving the motor to run, and a controller for controlling the driver. Among them, in addition to installing an angle sensor (i.e., a magnet and an encoder to be calibrated) on the motor, an additional reference encoder needs to be superimposed. The reference encoder and the encoder to be calibrated are both used to detect the rotation angle of the motor; the reference encoder can be an encoder with higher measurement accuracy than the encoder to be calibrated. Generally, a calibrated optical encoder is selected to output an accurate reference angle. At the same time, a computer host computer is also included, which is used to determine the angle error (i.e., angle correction parameter) based on the reference angle sent by the reference encoder and the angle to be calibrated sent by the encoder to be calibrated, and send the angle error to the encoder to be calibrated to complete the calibration. When the calibration is completed, the reference encoder and the computer host computer need to be removed, and then the motor will run again. At this time, the motor is in a normal working state. The encoder to be calibrated that has completed the calibration detects the rotation angle of the motor in real time, and sends the real-time angle generated according to the rotation angle and the angle correction parameter to the controller. The controller generates a drive signal based on the real-time angle and sends the drive signal to the driver. The driver adjusts the rotation of the motor in real time according to the drive signal. This requires additional installation and removal of the reference encoder and the host computer, which is very inconvenient.

[0008] Therefore, the related technology of non-sensing calibration has been produced. In the related technology, when it is necessary to self-calibrate the angle correction parameters, a closed-loop control system can be used to enable the controller to directly generate a drive signal according to the real-time angle and send the drive signal to the driver. The driver adjusts the rotation of the motor in real time according to the drive signal so that the motor can correct and maintain uniform rotation. At the same time, the angle correction parameter self-calibration method is used to continuously self-calibrate the angle correction parameters according to the real-time angle and the stored angle correction parameters, and then continuously output a more accurate real-time angle.

[0009] However, when using the above-mentioned sensorless calibration technology, in some special circumstances, such as in the initial state, error state, or when switching scenes with large speed changes, the stored or set angle correction parameters may differ too much from the accurate angle correction parameters. If the real-time angle is obtained and the drive signal is generated based on these stored or set angle correction parameters, the motor may deviate more and more, or the motor may not be able to reach a stable operating state for a long time, making it difficult to achieve the self-calibration effect of the angle correction parameters.

[0010] It can be seen that in the system of the above-mentioned related technology, the inventor believes that the following problems exist: 1. It is necessary to compare and calibrate with the reference encoder, which adds additional equipment; 2. It is necessary to install additional equipment such as the reference encoder and the host computer before calibrating the angle correction parameters; after the calibration is completed, it is necessary to remove the installed reference encoder, the host computer and other additional equipment before restoring the normal working state. The normal working state and the non-working state here cannot be switched in a senseless manner by internal instructions; 3. It may cause the motor to deviate more and more, and the self-calibration effect of the angle correction parameters cannot be achieved.

[0011] Therefore, there is a need for a calibration system that can automatically calibrate angle correction parameters without installing or removing additional equipment. Summary of the invention

[0012] In order to automatically calibrate the angle correction parameters without installing or removing additional equipment, the present application provides a calibration system and method for open-loop self-calibration of a motor.

[0013] In a first aspect, the present application provides a calibration system for open-loop self-calibration of a motor, which adopts the following technical solution: a calibration system for open-loop self-calibration of a motor, comprising: an angle sensor, which is arranged on the motor, and is used to detect the rotation angle of the motor, wherein the angle sensor includes an angle correction module, and the angle correction module is used to correct the rotation angle according to an angle correction parameter and then output a real-time angle, and the angle correction module has an angle correction parameter self-calibration function, so as to self-calibrate the angle correction parameter when the motor is in uniform rotation in response to a calibration signal; and a controller, which is communicatively connected to a driver for driving the motor to operate, and the controller is configured to obtain the operating physical parameters of the motor, generate a drive signal according to the operating physical parameters, and send the drive signal to the driver, wherein the operating physical parameters can reflect the operating conditions of the motor, and the drive signal is used to control the driver to adjust at least one drive physical parameter to adjust the motor to uniform rotation.

[0014] A further solution is that the angle correction module includes: a parameter calculator, which is used to receive the rotation angle, and calculate the angle correction parameter based on the rotation angle in response to the calibration signal and output a new angle correction parameter.

[0015] A further solution is that the angle correction module also includes: an error corrector, which is communicatively connected to the parameter calculator to receive the new angle correction parameter, and outputs the real-time angle after correcting the rotation angle according to the new angle correction parameter; wherein the rotation angle is simultaneously input into the angle input end of the parameter calculator and the angle input end of the error corrector, the output end of the parameter calculator is connected to the parameter input end of the error corrector, and the output end of the error corrector is used to output the real-time angle.

[0016] A further solution is that the angle correction module also includes: a system stability monitor, which is used to receive the rotation angle, and determine whether the system is stable based on the rotation angle, and enable the parameter calculator when the system is stable; wherein the rotation angle is first input into the system stability monitor, and then input into the parameter calculator through the system stability monitor, and the output end of the system stability monitor is connected to the angle input end of the parameter calculator.

[0017] A further solution is that the angle correction module also includes: a trigger button, which accepts the operator's input to output the calibration signal, and is used to manually trigger the calibration of the angle correction parameters in an initial state or an error state, and its output end is connected to the system stability monitor.

[0018] A further solution is that the output end of the trigger button is connected to the system stability monitor and the parameter calculator at the same time.

[0019] A further solution is that the angle correction module further includes: a non-volatile memory for storing the new angle correction parameters and providing them to the parameter calculator after the system is powered on again.

[0020] A further solution is that the angle correction module also includes: a trigger button, which accepts the operator's input to output the calibration signal, and is used to manually trigger the calibration of the angle correction parameters in an initial state or an error state, and its output end is connected to the parameter calculator.

[0021] A further solution is that the controller includes: a FOC algorithm module, which is used to obtain current parameters associated with the operation of the motor and generate the drive signal according to the current parameters, wherein the operating physical parameter is the current parameter.

[0022] A further solution is that the angle sensor is one of a magnetic angle sensor, a photoelectric angle sensor, and a resistive angle sensor.

[0023] In a second aspect, the present application also provides a calibration method for open-loop self-calibration of a motor, which adopts the following technical solution: a calibration method for open-loop self-calibration of a motor, comprising: setting an angle sensor on the motor, the angle sensor being used to detect the rotation angle of the motor, wherein the angle sensor includes an angle correction module, and the angle correction module has an angle correction parameter self-calibration function; configuring a controller to be communicatively connected to a driver for driving the motor to operate, and configuring the controller to obtain operating physical parameters of the motor, generate a drive signal according to the operating physical parameters, and send the drive signal to the driver, wherein the operating physical parameters can reflect the operating conditions of the motor, and the drive signal is used to control the driver to adjust at least one drive physical parameter to adjust the motor to uniform rotation; self-calibrating the angle correction parameter when the motor is in uniform rotation according to the calibration signal; using the angle sensor to correct the rotation angle according to the calibrated angle correction parameter and then output a real-time angle.

[0024] In summary, the present application can start and complete the self-calibration of the angle correction parameters without the need to install or remove additional equipment such as a reference encoder or a host computer. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The figure is a system block diagram for realizing “drag-and-drop” calibration in the prior art.

[0026] Figure 2 This is a block diagram of the calibration system used for open-loop self-calibration of a motor in this application.

[0027] Figure 3 This is a block diagram of the internal structure of an angle correction module according to an embodiment of the present application.

[0028] Figure 4 This is a block diagram of the internal structure of an angle correction module according to another embodiment of the present application. DETAILED DESCRIPTION

[0029] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0030] The following describes an embodiment of the present application in conjunction with the drawings in the specification, but the embodiment should not be construed as limiting the present application.

[0031] refer to Figure 2 , Figure 2The block diagram of the calibration system for open-loop self-calibration of a motor in the present application is shown in FIG. The embodiment of the present application provides a calibration system for open-loop self-calibration of a motor, including a driver, an angle sensor and a controller.

[0032] The driver is used to drive the motor to operate, and the controller is communicatively connected to the driver. The controller is configured to obtain operating physical parameters that can reflect the operating conditions of the motor (such as the angle, speed, current, voltage, etc. of the motor operation), generate a drive signal according to the operating physical parameters (for example, in some embodiments, the drive signal can be a drive current value), and send the drive signal to the driver. The drive signal is used to control the driver to adjust at least one drive physical parameter to adjust the motor to a uniform speed. For example, the driver can adjust the motor operating current, voltage, and other drive physical parameters associated with the motor drive to adjust the rotation speed of the motor so that the motor reaches a uniform speed rotation state.

[0033] The angle sensor can be a magnetic angle sensor, a photoelectric angle sensor, a resistive angle sensor, etc., and the physical quantity sensed by the sensor is not limited. For the convenience of explanation, the embodiment of the present application uses a magnetic angle sensor (i.e., a magnetic encoder) for specific introduction. The magnetic encoder is fixedly arranged on the motor mover or stator. In the embodiment of the present application, the magnetic encoder is fixed relative to the stator of the motor, and the motor shaft is provided with a magnet, which rotates synchronously with the shaft, and the magnetic encoder is used to detect the rotation angle of the magnet. In other embodiments of the present application, an optical encoder can also be used to implement it. For example, the optical encoder can be fixed relative to the stator of the motor, and the motor shaft is provided with a grating, which rotates synchronously with the shaft, and the optical encoder is used to detect the rotation angle of the magnet.

[0034] Regarding the position of the magnetic encoder relative to the magnet, the magnetic encoder can adopt an on-axis detection scheme or an off-axis detection scheme. On-axis detection and off-axis detection are two different ways of magnetic induction detection in the art. It is understandable that the magnetic encoder provided in the present application adopts an on-axis detection scheme, and the magnetic encoder is located on the axial side of the magnet along the output shaft of the motor to obtain a higher angle detection accuracy.

[0035] It can be understood that in the embodiment of the present application, the angle sensor includes an angle correction module, which has an angle correction parameter self-calibration function, for outputting a real-time angle after correcting the rotation angle according to the angle correction parameter, and self-calibrating the angle correction parameter when the motor is in uniform rotation in response to a calibration signal.

[0036] Since the present patent application adopts a self-calibration method to obtain the angle correction parameters, referring to the implementation method of the parameter calculator disclosed later in the present patent application, a relatively accurate angle correction parameter can be obtained only when the motor keeps rotating at a constant speed.

[0037] Through observation and comparison, the inventor found that when the motor speed is not much different (for example, the motor speed fluctuation can achieve a good effect within 5%, for example, 1000 revolutions per minute, the speed fluctuation error is less than 50rpm, it can be understood that the speed fluctuation of 5% is not an absolute value, but the greater the speed fluctuation, the worse the calibration effect will be, not to say invalid.), different operating speeds correspond to basically the same angle correction parameters. Within the normal operating range of the motor, you can arbitrarily select a speed to keep the motor rotating at the speed, and the angle correction parameter calculated can be applied to other operating speeds of the motor that are not much different. Therefore, the key to calibrating the angle correction parameter is to maintain the uniform rotation of the motor at a certain speed, and it is not necessary to use the real-time angle output by the motor after calibration for motor speed control. Therefore, in the embodiment of the present application, the closed-loop control system can be changed to an open-loop control system, that is, in the calibration stage, it is not necessary to feed back the real-time angle output by the angle sensor to the controller, but other technical means are used to maintain the uniform rotation of the motor at a certain speed. In this way, it can be avoided that the initial angle correction parameter is too unstable and excessively affects the motor speed control.

[0038] Specifically, a certain sensor can be used to obtain a certain operating physical parameter of the motor. For example, a current sensor can be used to obtain the current parameter of the motor, or a resistor can be used to convert the current parameter into a voltage parameter. It can be understood that the current sensor, resistor and other devices here can be on the driver, so as to directly obtain the current or voltage parameters of the motor and feed them back to the controller. In the driver of the motor system, there is generally a current sensor, and there is no need to add an additional current sensor. In addition, the controller, driver, current sensor, drive tube and other devices can be integrated on the same PCB board or set separately, and this application does not limit it. Then, using algorithms such as FOC (Field-Oriented Control, magnetic field oriented control or vector control), a drive signal is generated according to the obtained motor operation physical parameters (such as current parameters) to keep the motor rotating at a constant speed, eliminating the interference caused by the large difference between the stored or set angle correction parameters and the accurate angle correction parameters in an error or abnormal state, so as to self-calibrate the angle correction parameters faster and more accurately.

[0039] In other embodiments of the present application, an external controller and / or driver can even be used to control the motor to achieve a uniform rotation state. Although this method also requires the connection of an external device, it only requires the connection of a signal line, while related technologies such as "drag and drop" require manual operations such as assembly and disassembly of the reference encoder and the motor. Therefore, this method is also simpler and more convenient than related technologies such as "drag and drop".

[0040] When the real-time angle is generated according to the rotation angle, it can be determined whether the angle correction parameter needs to be self-calibrated according to the calibration signal. The calibration signal indicates whether the angle correction parameter needs to be self-calibrated at present. When the angle correction parameter does not need to be self-calibrated, the angle correction module will correct the rotation angle according to the set angle correction parameter and output the real-time angle; when the angle correction parameter needs to be self-calibrated, the angle correction module will calculate the set angle correction parameter according to the rotation angle and the set angle correction parameter and output a new angle correction parameter, and the angle correction module will correct the rotation angle according to the new angle correction parameter and output the real-time angle. The new angle correction parameter will also replace the set angle correction parameter, and repeat the calculation process of the angle correction parameter, so as to continuously iterate and update, thereby obtaining more and more accurate angle correction parameters and realizing self-calibration of the angle correction parameters.

[0041] Reference Figure 3 , Figure 3 The figure is a block diagram of the internal structure of the angle correction module of an embodiment of the present application. The angle correction module may include a parameter calculator and an error corrector. As shown in the figure, the rotation angle is simultaneously input to the angle input end of the parameter calculator and the angle input end of the error corrector, the output end of the parameter calculator is connected to the parameter input end of the error corrector, and the output end of the error corrector is used to output the real-time angle. Among them, the parameter calculator is used to receive the rotation angle, and respond to the calibration signal and calculate the angle correction parameter based on the rotation angle and then output a new angle correction parameter. The error corrector is communicatively connected to the parameter calculator to receive the new angle correction parameter, and corrects the rotation angle according to the new angle correction parameter and then outputs the real-time angle.

[0042] The rotation angle is simultaneously input to the angle input end of the parameter calculator and the angle input end of the error corrector, the output end of the parameter calculator is connected to the parameter input end of the error corrector, and the output end of the error corrector is used to output the real-time angle.

[0043] For the implementation of parameter calculator and error trimmer, please refer to the attached Figure 4 Description.

[0044] Reference Figure 4 , Figure 4 This is a block diagram of the internal structure of an angle correction module according to another embodiment of the present application. In this embodiment, the angle correction module includes a parameter calculator, an error corrector, a system stability monitor, a non-volatile memory and a trigger button.

[0045] Continue to refer to Figure 4In this embodiment, the rotation angle is simultaneously input to the input end of the system stability monitor and the angle input end of the error corrector. The output end of the system stability monitor is connected to the angle input end of the parameter calculator. The system stability monitor is used to receive the rotation angle, and judge whether the system is stable according to the rotation angle, and enable the parameter calculator when the system is stable. The output end of the parameter calculator is connected to the parameter input end of the error corrector. The parameter calculator is used to receive the rotation angle, and respond to the calibration signal and calculate the angle correction parameter based on the rotation angle and output a new angle correction parameter. The error corrector is used to receive the rotation angle, and correct the rotation angle according to the new angle correction parameter and output the real-time angle. There is a two-way communication between the parameter calculator and the non-volatile memory. The parameter calculator can write the new angle correction parameter into the non-volatile memory, and can also read the stored angle correction parameter from the non-volatile memory. The trigger button accepts the input of the operator to output the calibration signal, which is used to manually trigger the calibration of the angle correction parameter in the initial state or error state. Its output end can be connected to the system stability monitor to trigger the start of the system stability monitor. Therefore, professionals can make a more professional judgment on whether to start the system stability monitoring according to different use environments and conditions. This judgment can also indirectly trigger whether to perform self-calibration on the angle correction parameters and / or whether to perform error correction on the rotation angle. The trigger button output end can also be connected to the trigger end of the parameter calculator to trigger the parameter calculator to calculate the angle correction parameters to complete self-calibration. In this way, in some scenarios where the calibration error is too large, this function can be manually turned off, and the angle correction parameters stored in the previous system are used to perform error correction on the rotation angle output by the magnetic encoder; it can also be used to indirectly trigger whether to perform error correction on the rotation angle; it can also be used to trigger the parameter calculator to write new angle correction parameters to the non-volatile memory or read the stored angle correction parameters from the non-volatile memory. Professionals can decide whether to read or store the angle correction parameters based on the current correction effect.

[0046] There are many ways to implement the system stability monitor. You can use a speed stability detection sensor commonly used in the field, or you can use a self-detection method disclosed in the patent with publication number CN116892970A to detect speed stability. The method is as follows. Set N angle reference points {ref[0], ref[1]...ref[n-1], ref[n]...ref[N-1]} in sequence from 0 to 360 degrees, and record the time points {TS[0], TS[1]...TS[n-1], TS[n]...TS[N-1]} when the angle output value of the magnetic encoder passes through each angle reference point. These time points are called timestamps. For the angle reference point ref[n], the qth period of the shaft passing through ref[n] is recorded as Pq. Ref[n] is measured multiple times and the period of the shaft is recorded to form a period data set: {P1, P2…Pq-1, Pq…PQ}. Taking ref[n] as an example, the time when the angle output value of the magnetic encoder passes through ref[n] for the second and first time is the period P1 of the shaft measured by ref[n]; when the angle output value of the magnetic encoder passes through ref[n] for the third and second time, it is the period P2 of the shaft measured by ref[n], and so on. Then the period set {P1, P2…Pq-1, Pq…PQ} is calculated to obtain the average period P of the shaft. The system can also use the average period P of the shaft as an indicator for judging the stability of the magnetic encoder. Then, the system can be judged according to one of the following methods to determine whether it meets the prerequisites for entering a stable state: (1) Calculate whether the absolute value of the difference between the current period Pq and the previous period Pq-1 is less than the first preset value Rlim1, that is, determine whether the formula |Pq-Pq-1|<Rlim1 is established; (2) Determine by the relationship between the difference between the timestamps TS[n] and TS[n-1] of two adjacent reference points ref[n] and ref[n-1] and the angle between the two reference points ref[n] and ref[n-1], that is, determine whether the formula |Pq-Pq-1|<Rlim1 is established; (3) Determine by the relationship between the timestamps TS[n] and TS[n-1] of two adjacent reference points ref[n] and ref[n-1] and the angle between the two reference points ref[n] and ref[n-1]. (3) Calculate whether the absolute value of the difference between the current period Pq and P is less than the third preset value Rlim3, that is, determine whether the formula |Pq-P|<Rlim3 is established. When the corresponding formula is established according to one of the above methods (the system meets the prerequisite for entering a stable state), and the formula continues to be established for a certain number of times, it is determined that the system has entered a stable state.

[0047] The above method disclosed in the patent CN116892970A mainly determines whether the rotation speed value of the rotating shaft is stable by calculating the difference between each cycle, thereby realizing the detection of stable speed and overcoming the influence of the jitter of the magnetic encoder angle output value caused by noise. Under the guidance of this method, those skilled in the art can easily adjust the method to design other self-detection methods with the same principle but different specific operation steps. For example, the variance of the cycle or speed can be calculated. When the number of times the variance of the cycle or speed is less than a preset value reaches a predetermined number within a certain period of time, it is judged to be in a stable state; or, the respective period data sets can be calculated for multiple angle reference points ref[n], and when using one of the methods (1)-(3) to judge whether the system has entered a stable state, the period data calculated for each of the multiple angle reference points ref[n] are considered; or, after judging that the corresponding formula is established according to one of the methods (1)-(3) (judging that the system meets the prerequisite for entering a stable state), although the formula cannot be established continuously for a certain number of times, it is also judged that the system has entered a stable state under the premise of meeting certain conditions. Those skilled in the art can also use non-self-calibration methods to determine whether the rotation speed is stable, such as setting a certain signal source on the motor rotor or stator, setting a detection device for the signal source at the other end of the rotor or stator, and calculating the motor rotation period or speed by detecting whether the relative position between the signal source and the detection device returns to the initial state, and judging whether the rotation is stable based on the calculated rotation period or speed. This application is not limited here.

[0048] There are also many ways to implement the parameter calculator. For example, patent application CN117168530A discloses a self-calibration method for a magnetic encoder, which is described as follows. For example, in order to obtain the angle correction parameters in this application, N angle reference points are set in sequence from 0 to 360 degrees, and the initial values ​​of N nonlinear angle error reference values ​​are set accordingly. The time point when the angle output value of the magnetic encoder passes through each angle reference point is recorded. This time point is called a timestamp. This time point is actually affected by noise and is not stable, but the noise is suppressed by subsequent multiple iterative averaging filtering calculations (such as the low-pass filtering calculation introduced later). Then, it is determined whether the rotation of the shaft is in a uniform rotation state. If so, the N nonlinear angle error reference values ​​are iterated, specifically based on the prior angle reference point. and at the rear angle reference point The nonlinear angle error reference value at the next angle reference point is calculated based on the difference in the corresponding timestamps, the rotation period P of the shaft, and the nonlinear angle error reference value corresponding to the previous angle reference point. Calculate the actual angle of rotation from the previous angle reference point to the next angle reference point , and then use Calculate the rear angle reference point The corresponding new nonlinear angle error reference value is: is the timestamp corresponding to the previous angle reference point, is the timestamp corresponding to the subsequent angle reference point, P is the rotation period, and the calculation method of P is described in the subsequent part of this patent application. Then, the nonlinear angle error reference values ​​obtained in the past are filtered and calculated, for example, using low-pass filtering to obtain the filtered nonlinear angle error reference value, and this operation is performed on all angle reference points. For example, the low-pass filtering calculation can be specifically used ,in, for The filtered value, Angle reference point The corresponding nonlinear angle error reference value obtained last time, Angle reference point The corresponding new nonlinear angle error reference value, is the low-pass filter coefficient, and 0< ≤1. Then, the average value of the nonlinear angle error reference value after filtering at each angle reference point is taken. Specifically, , and subtract the average value from each filtered nonlinear angle error reference value. Specifically, , thereby eliminating the zero offset of the nonlinear angle error reference value. , as the nonlinear angle error reference value of the final output (equivalent to the "angle correction parameter" in this application).

[0049] In the above method disclosed in CN117168530A, the calculation method of the rotation period P is as follows: first calculate the difference between two time stamps of two adjacent rotations of the same angle reference point. If this difference is greater than a certain threshold value Pmin (due to the presence of noise, the signal has a small probability of rapidly shaking left and right near the angle reference point, such as near 22.5 degrees, which may cause the time of passing 22.5 degrees twice to be recorded, but the time interval between these two times is very small and is not a cycle. In order to exclude this situation, a minimum threshold value Pmin is set according to the maximum speed that may be encountered in actual use of the motor. Only when the time of passing a certain angle reference value twice is greater than Pmin, the difference between the two times is considered as a cycle), then the difference is used as the rotation period obtained based on the angle reference point to exclude the influence of excessive noise on the calculation result; the rotation period can be taken as the period of the next round of rotation, or the rotation period obtained based on multiple angle reference points can be averaged and processed to obtain the period of the next round of rotation. Then the periods obtained from the previous rotations are low-pass filtered to obtain the filtered period as the rotation period P outputted by the final calculation.

[0050] For another example, patent application CN115355937A also discloses a self-calibration method for a magnetic encoder, which is specifically as follows. For example, in order to obtain the angle correction parameter in this application, the angle value θdet(ij) outputted by the magnetic encoder for the jth time in the i-th round is low-pass filtered to improve the linearity of the detection data; the filtered value θfilt(ij) obtained after filtering is regarded as the result of the linearity correction of the detection value θdet(ij). N reference points θref(n) are set within 0 to 360 degrees, and the detection value θdet(ij) closest to each reference point θref(n) in each cycle is selected, and θcal(in)=θfilt(ij)-θdet(ij) is taken as the difference between the correction result and the measurement result, which is used as the adjustment value of the i-th cycle of the reference point θref(n). For each reference point, there are p corresponding adjustment values ​​in p periods. Averaging the p adjustment values ​​can obtain a more accurate target adjustment value θcal(n). Thus, each reference point can obtain the corresponding target adjustment value θcal(n), thereby forming an adjustment reference table (equivalent to the "angle correction parameter" in this application).

[0051] For another example, the parameter calculator can also perform a Z transform on the angle error to calculate the coefficients of each harmonic component, so that the coefficients of each harmonic component are used to compensate the input angle in the error corrector to obtain a corrected real-time angle value.

[0052] In an embodiment of the present application, the system stability monitor is used to monitor the stability of the system to ensure that calibration is performed only when the system is stable, thereby reducing the storage or use of erroneous or more erroneous angle correction parameters as new angle correction parameters when the system is unstable.

[0053] It is understandable that after the system has been running stably for a period of time, the new angle correction parameters that are continuously calculated (i.e., self-calibrated) by the parameter calculator are the optimal parameters that are more in line with the current use environment and system. However, when the system loses power, the above optimal parameters will be lost, and the system needs to continue to calculate (i.e., self-calibrate) to obtain the optimal parameters again. In order to reduce the loss of optimal parameters, a non-volatile memory is added, which is used to store the new angle correction parameters (optimal parameters) and provide them to the parameter calculator after the system is powered on again.

[0054] It is understandable that in a motor system, especially a high-speed motor system, when the high-speed motor is in a normal working state, the high-speed motor is easily in a stable state. Therefore, it is appropriate to consider whether to add a system stability monitor in this usage scenario.

[0055] It is understandable that the system stability monitor, non-volatile memory, trigger button and other devices in this embodiment can be selected according to the needs of the actual use environment, and this application does not limit it. For example, you can choose to include a system stability monitor and a non-volatile memory, or you can choose to include a system stability monitor and a trigger button, or you can choose to include a non-volatile memory and a trigger button, or you can choose to include a system stability monitor, a non-volatile memory and a trigger button, and other different combinations.

[0056] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. The specific working process of the above-described system, device and unit can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0057] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. If the integrated unit is implemented in the form of a software functional unit and sold or used as a separate product, it can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present application is essentially or part of the contribution to the prior art or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes a number of instructions for a computer device or processor to perform all or part of the steps of the method described in each embodiment of the present application.

[0058] The above embodiments are only used to introduce the technical solution of the present application in detail, but the description of the above embodiments is only used to help understand the method and core idea of ​​the present application and should not be understood as limiting the present application. Any changes or substitutions that can be easily thought of by technicians in this technical field within the technical scope disclosed in the present application should be included in the protection scope of the present application.

Claims

1. A calibration system for open-loop self-calibration of a motor, characterized in that: include: An angle sensor is provided on the motor and is used to detect the rotation angle of the motor, wherein the angle sensor comprises an angle correction module, the angle correction module is used to correct the rotation angle according to an angle correction parameter and then output a real-time angle, and the angle correction module has an angle correction parameter self-calibration function, so as to perform self-calibration on the angle correction parameter when the motor is rotating at a constant speed in response to a calibration signal; and A controller is communicatively connected to a driver for driving the motor to operate, the controller is configured to obtain operating physical parameters of the motor, the operating physical parameters are not obtained from the angle sensor, a drive signal is generated according to the operating physical parameters, and the drive signal is sent to the driver, wherein the operating physical parameters can reflect the operating conditions of the motor, and the drive signal is used to control the driver to adjust at least one driving physical parameter to adjust the motor to a uniform speed.

2. The calibration system for open-loop self-calibration of a motor according to claim 1, characterized in that: The angle correction module comprises: The parameter calculator is used for receiving the rotation angle, and in response to the calibration signal and based on the rotation angle, calculating the angle correction parameter and outputting a new angle correction parameter.

3. The calibration system for open-loop self-calibration of a motor as claimed in claim 2, characterized in that: The angle correction module also includes: an error corrector, communicatively connected to the parameter calculator to receive the new angle correction parameter, and correct the rotation angle according to the new angle correction parameter and then output the real-time angle; Among them, the rotation angle is simultaneously input into the angle input end of the parameter calculator and the angle input end of the error corrector, the output end of the parameter calculator is connected to the parameter input end of the error corrector, and the output end of the error corrector is used to output the real-time angle.

4. The calibration system for open-loop self-calibration of a motor as claimed in claim 3, characterized in that: The angle correction module also includes: a system stability monitor, configured to receive the rotation angle, determine whether the system is stable according to the rotation angle, and enable the parameter calculator when the system is stable; The rotation angle is first input into the system stability monitor, and then input into the parameter calculator through the system stability monitor, and the output end of the system stability monitor is connected to the angle input end of the parameter calculator.

5. The calibration system for open-loop self-calibration of a motor as claimed in claim 4, characterized in that: The angle correction module also includes: A trigger button receives an operator's input to output the calibration signal, and is used to manually trigger calibration of the angle correction parameter in an initial state or an error state, and its output end is connected to the system stability monitor.

6. The calibration system for open-loop self-calibration of a motor as claimed in claim 5, characterized in that: The output end of the trigger button is connected to the system stability monitor and the parameter calculator at the same time.

7. The calibration system for open-loop self-calibration of a motor as claimed in claim 2, characterized in that: The angle correction module also includes: The non-volatile memory is used to store the new angle correction parameters and provide them to the parameter calculator after the system is powered on again.

8. The calibration system for open-loop self-calibration of a motor as claimed in claim 2, characterized in that: The angle correction module also includes: A trigger button receives an operator's input to output the calibration signal, and is used to manually trigger calibration of the angle correction parameter in an initial state or an error state, and its output end is connected to the parameter calculator.

9. The calibration system for open-loop self-calibration of a motor according to claim 1, characterized in that: The controller comprises: The FOC algorithm module is used to obtain current parameters associated with the operation of the motor and generate the drive signal according to the current parameters, wherein the operating physical parameter is the current parameter.

10. The calibration system for open-loop self-calibration of a motor according to any one of claims 1 to 9, characterized in that: The angle sensor is one of a magnetic angle sensor, a photoelectric angle sensor, and a resistive angle sensor.

11. A calibration method for open-loop self-calibration of a motor, characterized in that: include: An angle sensor is arranged on the motor, the angle sensor is used to detect the rotation angle of the motor, wherein the angle sensor comprises an angle correction module, and the angle correction module has an angle correction parameter self-calibration function; The controller is configured to be communicatively connected to a driver for driving the motor to operate, and the controller is configured to obtain an operating physical parameter of the motor, the operating physical parameter is not obtained from the angle sensor, a driving signal is generated according to the operating physical parameter, and the driving signal is sent to the driver, wherein the operating physical parameter can reflect the operating condition of the motor, and the driving signal is used to control the driver to adjust at least one driving physical parameter to adjust the motor to a uniform speed rotation; Self-calibrating the angle correction parameter according to the calibration signal when the motor is rotating at a constant speed; The angle sensor is used to correct the rotation angle according to the calibrated angle correction parameter and then output a real-time angle.

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