Method for suppressing transient current of electric steering engine

Abstract

The invention discloses a method for suppressing transient current of an electric steering engine. The method comprises the following steps: acquiring a calculated value of a control quantity; acquiring a fluctuation value of the input instruction; if the fluctuation value of the input instruction does not exceed a first threshold value, outputting a calculated value of the control quantity; if the fluctuation value of the input instruction exceeds the first threshold value and the calculated value of the control quantity exceeds a second threshold value, a current limiting algorithm is executed, the current limiting algorithm is used for reducing the increase rate of the control quantity within preset time, and the second threshold value is determined according to the frequency characteristic of the electric steering engine. According to the method, the current limiting algorithm is adopted, the suppression effect on the transient current can be achieved without changing hardware of the electric steering engine, meanwhile, the second threshold value is determined according to the frequency characteristic of the electric steering engine, and it is guaranteed that the current limiting algorithm cannot reduce the performance of the electric steering engine.

Description

Technical Field

[0001] The invention belongs to the technical field of electric steering gears, and in particular relates to a method for suppressing transient current of an electric steering gear. Background Art

[0002] The electric servo is driven by a motor, which increases the output torque through a reducer. Due to the reducer, the working current of the servo is often small, but when the servo changes at a large angle, the instantaneous starting current will be several times the rated working current and dozens of times the no-load working current. This transient current characteristic can easily instantly reduce the power supply output or damage the power components of the motor drive circuit, causing product failure or damage. To address the problem of excessive transient current in electric servos, motor drive current limiting or other hardware methods are often used to improve it, but it is often difficult to achieve significant results or cause a significant decrease in the performance of the servo, such as speed and bandwidth. Summary of the invention

[0003] An object of the present invention is to provide a method for suppressing transient current of an electric servo, which can solve the technical problem in the prior art that excessive transient current of an electric servo causes product failure and damage.

[0004] According to a first aspect of the present invention, there is provided a method for suppressing transient current of an electric steering gear, comprising:

[0005] Obtaining a calculated value of a control quantity, wherein the control quantity is a PWM control quantity to be output to a motor drive, which is calculated by a servo control algorithm after the electric servo controller collects position instructions and position feedback of an electric servo output shaft;

[0006] Get the fluctuation value of the input command;

[0007] If the fluctuation value of the input command does not exceed a first threshold, outputting a calculated value of the control amount;

[0008] If the fluctuation value of the input command exceeds the first threshold, and the calculated value of the control amount exceeds the second threshold, a current limiting algorithm is executed, wherein the current limiting algorithm is used to reduce the increase rate of the control amount within a preset time, wherein the second threshold is determined according to the frequency characteristics of the electric servo.

[0009] Optionally, when the calculated value of the control amount exceeds a second threshold, executing a current limiting algorithm includes:

[0010] Get the control amount of the last actual output;

[0011] When the control amount actually output last time is less than a third threshold, controlling the control amount to increase at a first rate;

[0012] When the control amount actually output last time is greater than or equal to the third threshold, controlling the control amount to increase at a second rate;

[0013] The second rate is greater than the first rate, and the third threshold is greater than the second threshold.

[0014] Optionally, when the control amount actually output last time is less than the third threshold, the control amount output this time is calculated according to the following formula:

[0015] U out =U outpre +r1*(u a -α);

[0016] Among them, U out is the control quantity of this output, U outpre is the control quantity output last time, r1 is the first growth coefficient, u a is the calculated value of the control amount, and α is the second threshold.

[0017] Optionally, when the control amount actually output last time is greater than or equal to the third threshold, the control amount output this time is calculated according to the following formula:

[0018] U out =U outpre +r2;

[0019] Among them, U out is the control quantity of this output, U outpre is the control quantity output last time, and r2 is the second growth coefficient.

[0020] Optionally, the first growth coefficient and the second growth coefficient are determined in the following manner:

[0021] Get the start time and current limiting target of the electric servo;

[0022] determining, according to the start-up time of the electric steering gear, a first time when the current of the electric steering gear increases to the current limiting target and a second time when the current of the electric steering gear decreases from the current limiting target to a normal current;

[0023] The first growth coefficient and the second growth coefficient are determined according to the first time and the second time.

[0024] Optionally, the second threshold is determined by:

[0025] applying corresponding instructions to the electric servo according to the frequency characteristics of the electric servo;

[0026] Obtaining a maximum observed value of a control variable of the electric servo;

[0027] The second threshold is determined according to a maximum observed value of the control amount of the electric steering gear, wherein the second threshold is greater than the maximum observed value of the control amount of the electric steering gear.

[0028] According to a second aspect of the present invention, there is provided an electronic device comprising a processor and a memory, wherein the memory stores a program or instruction that can be run on the processor, and when the program or instruction is executed by the processor, the steps of a method for suppressing transient current of an electric servo as described in the first aspect of the present invention are implemented.

[0029] According to a third aspect of the present invention, there is provided an electric steering gear, comprising the electronic device according to the second aspect of the present invention.

[0030] According to a fourth aspect of the present invention, a readable storage medium is provided, on which a program or instruction is stored. When the program or instruction is executed by a processor, the steps of a method for suppressing transient current of an electric servo as described in the first aspect of the present invention are implemented.

[0031] The beneficial effect of the present invention is that the present invention reduces the growth rate of the control quantity by executing the current limiting algorithm after the command fluctuation is large and the control quantity exceeds the second threshold value, thereby reducing the transient current of the electric servo, and avoiding the electric servo from malfunctioning or being damaged due to excessive transient current. A current limiting algorithm is added to the control algorithm, and a mutation threshold is set for the output. When the servo is started instantly, if the error between the command and the feedback is large, the controller output can be limited at the start time, and the voltage applied to the motor winding instantly is reduced, thereby reducing the transient current of the electric servo. By adopting the current limiting algorithm, the suppression effect of the transient current can be achieved without changing the hardware of the electric servo. At the same time, the second threshold is determined according to the frequency characteristics of the electric servo, ensuring that the current limiting algorithm will not reduce the performance of the electric servo.

[0032] In addition to the rapidity index, the small-angle frequency characteristic index is also a very important dynamic characteristic index for electric servos. In order to ensure the dynamic performance of electric servos, the mutation threshold is selected to be higher than the maximum output during the frequency test, so that the current limiting algorithm will not have an adverse effect on the dynamic index. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The present invention is a flowchart of a method for suppressing transient current of an electric servo in an embodiment of the present invention.

[0034] Figure 2 Schematic diagram of an equivalent model of an armature circuit of a brushless DC motor in an embodiment of the present invention.

[0035] Figure 3Schematic diagram of current variation of an electric servo without executing a current limiting algorithm in an embodiment of the present invention.

[0036] Figure 4 Schematic diagram of the electric servo current change after the current limiting algorithm is executed in the embodiment of the present invention.

[0037] Figure 5 Schematic diagram of the controller output of the electric servo frequency sweep observation in an embodiment of the present invention. DETAILED DESCRIPTION

[0038] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

[0039] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0040] The techniques, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and devices should be considered as part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0041] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0042] In the specification and claims of the present invention, if the term "first" or "second" is involved, it may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally means that the related objects are in an "or" relationship.

[0043] The electric servo is driven by a motor, which increases the output torque through a reducer. Due to the reducer, the working current of the servo is often small, but when the servo changes at a large angle, the instantaneous starting current will be several times the rated working current and dozens of times the no-load working current. This transient current characteristic can easily instantly reduce the power supply output or damage the power components of the motor drive circuit, causing product failure or damage. To address the problem of excessive transient current in electric servos, motor drive current limiting or other hardware methods are often used to improve it, but it is often difficult to achieve significant results or cause a significant decrease in the performance of the servo, such as speed and bandwidth.

[0044] At present, the transient current of electric servos is mainly suppressed by hardware methods such as connecting power resistors in series with the power supply bus or adjusting the motor drive current limit. Connecting power resistors in series with the power supply bus can realize the voltage division function, reduce the voltage applied to the motor winding, and thus reduce the transient current of the electric servos. The current limiting of the driving current is to compare the potential difference between the voltage across the current limiting resistor and the current limiting standard voltage through a comparator. When the voltage across the current limiting resistor exceeds the set current limiting standard voltage, it is considered that the current limiting threshold is reached, and the drive output is turned off through the logic circuit to suppress the current.

[0045] The method of using series power resistors is essentially to reduce the transient current by dividing the voltage of the motor winding. Although this method can reduce the transient current, it will cause the motor speed to drop significantly, and the rapidity and dynamic performance of the servo will be significantly reduced. In addition, for high-power electric servos, the power resistors are large in size and easily generate heat accumulation, which is not conducive to the heat dissipation and heat protection capabilities of the product.

[0046] The transient current is suppressed by adjusting the current limiting resistor of the driving current. However, the sampling resistor is often not accurate and its resistance value fluctuates significantly with the change of temperature. The driving current limiting cannot be adjusted precisely. When the electric servo changes at a large angle, the transient current is too large, resulting in serious ground interference. As a result, the driving current limiting often affects the steady-state current of the electric servo, but has little effect on suppressing the transient current at startup.

[0047] like Figure 1 As shown, this embodiment introduces a method for suppressing transient current of an electric servo, including steps 1100-1400.

[0048] Step 1100: Obtain a calculated value of a control quantity, wherein the control quantity is a PWM control quantity to be output to a motor drive, which is calculated by a servo control algorithm after an electric servo controller collects position instructions and position feedback of an electric servo output shaft.

[0049] The electric servo system collects position commands and servo output shaft position feedback through the controller, and obtains the PWM control quantity to be output to the motor driver through the servo control algorithm. The motor driver drives the motor by solving the duty cycle of the PWM control signal to achieve position control of the servo. The larger the control quantity, the greater the maximum output speed of the servo. When the command changes significantly, the motor is in an instantaneous speed-up state. At this time, the controller calculates a full-duty PWM control signal to the motor driver through the PID control algorithm. At this time, the motor is in a state of sudden full-speed start. The equivalent model of the armature circuit of the brushless DC motor is as follows Figure 2 shown.

[0050] When the motor starts at full speed, the motor rotor speed θ accelerates from 0, and the motor's back electromotive force starts to increase from 0V. At the moment of starting, the power supply voltage is all added to the motor winding, causing a large transient current. As the rotor speed gradually increases, the motor back electromotive force increases, and the current gradually decreases to the current required for the servo to output the current torque.

[0051] Step 1200: Obtain the fluctuation value of the input instruction.

[0052] Step 1300: If the fluctuation value of the input instruction does not exceed the first threshold, output the calculated value of the control amount.

[0053] The fluctuation value of the input command can reflect whether the electric servo has a large angle change. The fluctuation value of the input command indicates the angle change value of the electric servo. If the fluctuation value of the input command does not exceed the first threshold, it means that the fluctuation is small. Although the fluctuation of the command will cause the current to change, when the fluctuation is small, the current change is within an acceptable range and will not cause malfunction or damage to the electric servo. In this case, there is no need to perform current limiting control, and the calculated value of the control amount can be directly output.

[0054] Step 1400: If the fluctuation value of the input command exceeds the first threshold, and the calculated value of the control amount exceeds the second threshold, a current limiting algorithm is executed, wherein the current limiting algorithm is used to reduce the increase rate of the control amount within a preset time, wherein the second threshold is determined according to the frequency characteristics of the electric servo.

[0055] The algorithm also needs to consider the situation that the control quantity output of the electric servo in actual operation fluctuates above and below the mutation threshold due to load changes. The mutation threshold is also the second threshold. Since the control quantity will exit the current limiting calculation every time it falls below the second threshold, when the control quantity fluctuates above and below the mutation threshold, the current limiting calculation will be repeatedly triggered in a short period of time, causing a large fluctuation in the control quantity. Therefore, the command fluctuation must also be judged in the current limiting trigger condition. The current limiting calculation will only be triggered when the input command fluctuation exceeds a certain range.

[0056] If the fluctuation value of the input command exceeds the first threshold, it means that the fluctuation is relatively large, in which case current limiting control is required. For example, when the electric servo is just started, the current will increase significantly in a short time, so current limiting control can be performed.

[0057] When determining whether current limiting control is required, it is also necessary to determine whether the calculated value of the control amount exceeds the second threshold. If the calculated value of the control amount does not exceed the second threshold, current limiting control is not required in this case, and the calculated value of the control amount is output normally. If the calculated value of the control amount exceeds the second threshold, the current limiting algorithm needs to be executed.

[0058] During the current limiting process, the output control quantity increase rate is reduced within the preset time, allowing the control quantity to increase at a specified rate. The preset time is related to the start time of the electric servo. Figure 3 As shown in the figure, without executing the current limiting algorithm, during the startup time of the electric servo, the current will increase rapidly to a peak value in a short period of time, and then quickly drop from the peak value to the normal current. The maximum value of the electric servo transient current is 42A. Figure 4 As shown in the figure, after executing the current limiting algorithm, the growth rate of the control quantity is reduced during the startup time of the electric servo, and the current peak is also controlled. The maximum value of the transient current of the electric servo is 28A, and the transient current of the electric servo is significantly reduced. When the servo moves at full speed, the PWM control signal is output with full duty cycle, so the maximum speed is not affected. Figure 4 The output quantity in is the control quantity.

[0059] The second threshold is a threshold used to determine whether to execute the current limiting algorithm, and is determined according to the frequency characteristics of the electric servo, so as to ensure that the frequency characteristics of the electric servo are not affected by the current limiting algorithm.

[0060] The present invention reduces the growth rate of the control quantity by executing a current limiting algorithm after the command fluctuation is large and the control quantity exceeds the second threshold value, thereby reducing the transient current of the electric servo, and preventing the electric servo from malfunctioning or being damaged due to excessive transient current. A current limiting algorithm is added to the control algorithm, and a mutation threshold is set for the output. When the servo is started instantly, if the error between the command and the feedback is large, the controller output can be limited at the start time, and the voltage applied to the motor winding instantly is reduced, thereby reducing the transient current of the electric servo. By adopting the current limiting algorithm, the suppression effect of the transient current can be achieved without changing the hardware of the electric servo, and the second threshold is determined according to the frequency characteristics of the electric servo, ensuring that the current limiting algorithm will not reduce the performance of the electric servo.

[0061] In this embodiment, step 1400 includes steps 1410-1430.

[0062] Step 1410: Obtain the control amount actually output last time.

[0063] Step 1420: When the control amount actually output last time is less than a third threshold, control the control amount to increase at a first rate.

[0064] Step 1430: When the control amount actually output last time is greater than or equal to the third threshold, control the control amount to increase at a second rate.

[0065] The second rate is greater than the first rate, and the third threshold is greater than the second threshold.

[0066] When the control amount actually output last time is less than the third threshold, it means that the current is relatively large at this time, and the control amount needs to be increased at a relatively small rate to limit the current.

[0067] If the control amount actually output last time is greater than the third threshold, the motor has already started to speed up and the transient current has been effectively suppressed. When the control amount exceeds the third threshold, it quickly increases to the control amount actually output by the PID operation to ensure that the maximum speed of the electric servo is not affected.

[0068] In this embodiment, when the control amount actually output last time is less than the third threshold, the control amount output this time is calculated according to the following formula:

[0069] U out =U outpre +r1(u a -α);

[0070] Among them, U out is the control quantity of this output, U outpre is the control quantity output last time, r1 is the first growth coefficient, u a is the calculated value of the control amount, and α is the second threshold.

[0071] In this embodiment, when the control amount actually output last time is greater than or equal to the third threshold, the control amount output this time is calculated according to the following formula:

[0072] U out =U outpre +r2;

[0073] Among them, U out is the control quantity of this output, U outpre is the control quantity output last time, and r2 is the second growth coefficient.

[0074] The current limiting calculation formula is specifically expressed as follows:

[0075]

[0076] Among them, Uout is the control quantity of this output, U outpre is the control quantity output last time, r1 is the first growth coefficient, r2 is the second growth coefficient, u a is the calculated value of the control amount, α is the second threshold, and β is the third threshold.

[0077] The first growth coefficient r1 and the second growth coefficient r2 can be tested through experiments. By selecting different growth coefficient values ​​to test the current change curve when the electric servo is started, the growth coefficient value that the current change curve meets the actual needs is selected.

[0078] After the operation output triggers the mutation threshold, the current limiting algorithm gradually increases in each operation cycle and adjusts the parameters according to the start-up time characteristics of the electric servo so that the control output reaches the maximum within the appropriate time. This can control the transient current and ensure that the maximum speed index of the electric servo is not affected.

[0079] In this embodiment, the method for determining the first growth coefficient and the second growth coefficient includes steps 2100-2300.

[0080] Step 2100: Obtain the start time and current limiting target of the electric servo.

[0081] The start-up time of the electric servo is determined according to the specific model of the electric servo, and the start-up time of different models of electric servos may be different.

[0082] The current limit target indicates the current limit target of the electric servo. Figure 3 As shown in the figure, when the current limiting algorithm is not used, the transient current at the start of the electric servo can reach 40, and the current limiting target can be set to 30 or other values. Different current limiting targets can be set for different models of electric servos. In addition, the current limiting target can be further set according to various other parameters such as the use scenario, working condition, load, etc. of the electric servo.

[0083] Step 2200: Determine, according to the start-up time of the electric actuator, a first time when the current of the electric actuator increases to the current limiting target and a second time when the current of the electric actuator decreases from the current limiting target to a normal current.

[0084] like Figure 3 As shown in FIG. 1 , during the start-up time of the electric servo, the current will increase rapidly to a peak value in a short period of time, and then decrease rapidly from the peak value. The current change curve when the electric servo is started can be tested experimentally, and the first time and the second time can be determined according to the current change curve.

[0085] Step 2300: Determine the first growth coefficient and the second growth coefficient according to the first time and the second time.

[0086] The first growth coefficient is a coefficient used to reflect the growth rate of the control amount in the first time. In the first time, the current value of the electric servo increases to the current limiting target. According to the current limiting target and the first time, the current growth rate of the electric servo in the first time can be determined, and then the first growth coefficient is determined. Different first growth coefficients are set for different current limiting targets.

[0087] The second growth coefficient is a coefficient used to reflect the growth rate of the control amount within the second time. Within the second time, the current value of the electric servo is reduced from the current limiting target to the normal current. According to the current limiting target and the second time, the current growth rate of the electric servo within the second time can be determined, and then the second growth coefficient is determined. Different second growth coefficients are set for different current limiting targets.

[0088] In this embodiment, the method for determining the second threshold includes steps 3100-3300.

[0089] Step 3100: applying corresponding instructions to the electric servo according to the frequency characteristics of the electric servo.

[0090] Step 3200: Obtain the maximum observed value of the control variable of the electric servo.

[0091] Step 3300: Determine the second threshold value according to the maximum observed value of the control amount of the electric steering gear, wherein the second threshold value is greater than the maximum observed value of the control amount of the electric steering gear.

[0092] Taking a certain type of electric servo as an example, its frequency characteristic index is a sinusoidal input signal with an amplitude of 1° and a frequency of 1Hz to 200Hz. Its amplitude-frequency and phase-frequency have a series of technical requirements. By setting the parameters of the PID control algorithm, the servo can meet the technical requirements of frequency characteristics. Then apply a command with an amplitude of 1° and a frequency of 1Hz to 200Hz to the electric servo, observe the output of the PID control, and select a suitable control output threshold. The threshold should be higher than the maximum value of the observed output. This ensures that the frequency characteristics of the electric servo are not affected by the current limiting algorithm. The controller output observed during the frequency sweep is shown in Figure 5 As shown, Figure 5 The output in is the control quantity output by the controller. For the convenience of observation, the output is displayed at 0.01 times.

[0093] The output of the servo controller adopts DSP digital control mode, with a main frequency of 150M. The main frequency of the general timer that outputs the PWM signal is set to 75M. In order to ensure that the PWM frequency output by the DSP pin to the motor driver is set to 12.5M, the comparison register used by the DSP to output the PWM signal is set to 6000 so that the PWM is output at full duty cycle. The PID control algorithm solves the instructions and feedback, and the output control value within 6000 controls the duty cycle of the PWM signal, thereby controlling the voltage applied to the winding. When the control value is 6000, all the voltage is output to the motor, and the motor speed is the maximum. When the control value is 0, the motor supply voltage is 0, and the motor does not rotate. Figure 5 It can be seen that when doing the sweep performance test, the maximum output of the controller is 1200, so the selected control output current limit threshold should be higher than this value. For example, the control output current limit threshold can be selected as 60% of the maximum output, and the maximum output is 6000, then the threshold is 3600.

[0094] In addition to the rapidity index, the small-angle frequency characteristic index is also a very important dynamic characteristic index for electric servos. In order to ensure the dynamic performance of electric servos, the mutation threshold is selected to be higher than the maximum output during the frequency test, so that the current limiting algorithm will not have an adverse effect on the dynamic index.

[0095] This embodiment introduces an electronic device, including a processor and a memory, wherein the memory stores a program or instruction that can be run on the processor, and when the program or instruction is executed by the processor, the steps of a method for suppressing transient current of an electric servo as described in any embodiment of the present invention are implemented.

[0096] This embodiment introduces an electric servo, including the electronic device described in the above embodiment of the present invention.

[0097] This embodiment introduces a readable storage medium, on which a program or instruction is stored. When the program or instruction is executed by a processor, the steps of a method for suppressing transient current of an electric servo as described in any embodiment of the present invention are implemented.

[0098] Although some specific embodiments of the present invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

[0099] Those of ordinary skill in the art will appreciate that the modules and algorithm steps described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0100] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described devices and equipment can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0101] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the modules is only a logical function division. There may be other division methods in actual implementation, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0102] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed on multiple network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the embodiments of the present invention.

[0103] In addition, each functional module in the embodiment of the present invention may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module.

[0104] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods of various embodiments of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, ROM, RAM, magnetic disks, or optical disks.

[0105] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

[0106] It should be understood that the size of the sequence number of each step in the content of the invention and the embodiments of the present invention does not absolutely mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention. For the purpose of example and description, the foregoing description of the implementation of the present disclosure has been given. The foregoing description is not exhaustive and is not intended to limit the present disclosure to the exact form disclosed. Various deformations and modifications may exist according to the above teachings, or various deformations and modifications may be obtained from the practice of the present disclosure. These embodiments are selected and described to illustrate the principles of the present disclosure and its practical application, so that those skilled in the art can use the present disclosure in various embodiments and various modifications suitable for the specific purpose conceived.

Claims

1. A method for suppressing transient current of an electric servo, characterized in that: include: Obtaining a calculated value of a control quantity, wherein the control quantity is a PWM control quantity to be output to a motor drive, which is calculated by a servo control algorithm after the electric servo controller collects position instructions and position feedback of an electric servo output shaft; Get the fluctuation value of the input command; If the fluctuation value of the input command does not exceed a first threshold, outputting a calculated value of the control amount; If the fluctuation value of the input command exceeds the first threshold, and the calculated value of the control amount exceeds the second threshold, a current limiting algorithm is executed, wherein the current limiting algorithm is used to reduce the increase rate of the control amount within a preset time, wherein the second threshold is determined according to the frequency characteristics of the electric servo.

2. The method according to claim 1, characterized in that: When the calculated value of the control amount exceeds the second threshold, executing the current limiting algorithm includes: Get the control amount of the last actual output; When the control amount actually output last time is less than a third threshold, controlling the control amount to increase at a first rate; When the control amount actually output last time is greater than or equal to the third threshold, controlling the control amount to increase at a second rate; The second rate is greater than the first rate, and the third threshold is greater than the second threshold.

3. The method according to claim 2, characterized in that When the control amount actually output last time is less than the third threshold, the control amount output this time is calculated according to the following formula: IN out =U outpre +r1*(in a -α); Among them, U out is the control quantity of this output, U outpre is the control quantity output last time, r1 is the first growth coefficient, u a is the calculated value of the control amount, and α is the second threshold.

4. The method according to claim 3, characterized in that: When the control amount actually output last time is greater than or equal to the third threshold, the control amount output this time is calculated according to the following formula: IN out =U outpre +r2; Among them, U out is the control quantity of this output, U outpre is the control quantity output last time, and r2 is the second growth coefficient.

5. The method according to claim 4, characterized in that The first growth coefficient and the second growth coefficient are determined in the following manner: Get the start time and current limiting target of the electric servo; determining, according to the start-up time of the electric steering gear, a first time when the current of the electric steering gear increases to the current limiting target and a second time when the current of the electric steering gear decreases from the current limiting target to a normal current; The first growth coefficient and the second growth coefficient are determined according to the first time and the second time.

6. The method according to claim 1, characterized in that The second threshold is determined by: applying corresponding instructions to the electric servo according to the frequency characteristics of the electric servo; Obtaining a maximum observed value of a control variable of the electric servo; The second threshold is determined according to a maximum observed value of the control amount of the electric steering gear, wherein the second threshold is greater than the maximum observed value of the control amount of the electric steering gear.

7. An electronic device, characterized in that: The invention comprises a processor and a memory, wherein the memory stores a program or instruction that can be run on the processor, and when the program or instruction is executed by the processor, the steps of a method for suppressing transient current of an electric servo as claimed in any one of claims 1 to 6 are implemented.

8. An electric steering gear, characterized in that: An electronic device comprising the electronic device described in claim 7.

9. A readable storage medium, characterized in that: The readable storage medium stores a program or instruction, and when the program or instruction is executed by the processor, the steps of a method for suppressing transient current of an electric servo as claimed in any one of claims 1 to 6 are implemented.

Images