A steering wheel angle signal checking method based on motor rotor position signal

Abstract

The application discloses a steering wheel rotation angle signal checking method based on motor rotor position signals and concretely relates to the technical field of vehicle-mounted electric power steering control, wherein the PWM rotation angle signal and the motor angle signal collected by the function implementation layer of the steering control unit are subjected to motor double-path signal checking; angle calculation is performed according to the PWM rotation angle signal and the motor angle signal; the vernier algorithm is used to obtain the initial position and the current absolute position; the motor angle conversion calculation is performed according to the angle calculation_S module and the angle calculation_P module; the calculated angle is subjected to checking analysis, and the output steering wheel angle is output; the safety monitoring layer of the steering control unit estimates the steering angle range according to the vehicle speed, the lateral acceleration, the proportional coefficient of the steering wheel and the front wheel rotation angle and the wheelbase, monitors the angle output by using the steering angle range, judges whether the error processing mechanism needs to be started, and enters the safety state or the normal working state.

Description

Technical Field

[0001] This invention relates to the field of vehicle electric power steering control technology, specifically to a method for verifying steering wheel angle signals based on motor rotor position signals. Background Technology

[0002] The existing steering wheel angle sensor technology based on PWM signal commonly used in automotive electric power steering systems is simple, easy to use, mature, and low in cost. It is compatible with a wide variety of microcontrollers (MCUs) and is suitable for mass production. However, relying on PWM-type steering wheel angle sensors to detect steering wheel angles carries the risk of reduced signal reliability or signal loss due to circuit signal failure. Summary of the Invention

[0003] Therefore, the present invention provides a method for verifying steering wheel angle signals based on motor rotor position signals to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a method for verifying steering wheel angle signals based on motor rotor position signals, comprising the following steps: Step 1: The PWM angle signal and motor angle signal collected by the function implementation layer of the steering control unit are used for dual-channel motor signal verification; Step 2: Perform angle calculation based on PWM rotation angle signal and motor angle signal: The vernier algorithm obtains the absolute position of the initial position and the current angle, and then the motor angle is converted and calculated according to the angle calculation_S module and the angle calculation_P module. The calculated angle is verified and analyzed, and the steering wheel angle is output. Step 3: The safety monitoring layer of the steering control unit estimates the steering angle range based on vehicle speed, lateral acceleration, the ratio coefficient of steering wheel to front wheel angle, and wheelbase. It then monitors the angle output using the steering angle range to determine whether the error handling mechanism needs to be activated, and enters a safe state or normal operation.

[0005] Preferably, the functional implementation layer of the steering control unit acquires PWM angle signals through a TAS sensor (Torque and Angle Sensor), which includes PWM_S and PWM_P, and acquires motor angle and speed signals through a position sensor; The angle calculation method in step 2 specifically includes: Based on the output signals PWM_S and PWM_P of the TAS sensor itself, a vernier operation is performed to initialize and update the absolute position signal of the current angle using the MPS absolute position signal to obtain the initial position signal. Based on the motor angle signal output by the position sensor and the initial position signal calculated by the vernier, a motor angle conversion operation is performed to obtain approximate steering wheel angle information.

[0006] Preferably, the cursor algorithm in step 2 specifically includes: At low speeds, the vernier is calculated based on the output signals PWM_S and PWM_P from the TAS sensor to obtain the absolute position and effective vernier position of the current angle. The vernier difference is calculated based on PWM_P and PWM_S. A theoretical value is calculated based on the vernier difference at the Nth step. The difference is then compared with the actual value. If the deviation is greater than the threshold (25%) or the speed is too fast, the vernier reliability is considered low, and the vernier angle is not used for verification. The rotational speed is determined by the angular velocity converted from the motor speed. When the vernier is valid, the absolute position of the current angle is passed to the angle calculation_S module and the angle calculation_P module for further real-time angle calculation. The initial absolute position signal is then passed to the motor angle conversion calculation module as the initial position of the steering wheel.

[0007] Preferably, the angle calculation module determines the initial position of the current angle based on the absolute position of the current angle calculated by the cursor, and then calculates the real-time rotation angle information Angle_S following the PWM_S signal based on the PWM_S signal. The angle calculation module _P determines the initial position of the current angle based on the absolute position of the current angle calculated by the cursor, and then calculates the real-time rotation angle information Angle_P that follows the PWM_P signal based on the PWM_P signal.

[0008] Preferably, the motor angle conversion calculation in step 2 specifically includes: At low speeds, the vernier algorithm module calculates the initial absolute position and sends it to the motor angle conversion calculation module to determine the initial position of the motor angle and the initial position of the steering wheel. Subsequently, as the motor angle changes during operation, the motor angle is converted into an approximate steering wheel angle Angle_MPS through a specific relationship between the motor angle and the steering wheel angle.

[0009] Preferably, the vernier algorithm calculates the initial position to determine the initial position of the motor angle. Specifically, during the operation of the steering control unit, the initial position is periodically updated and the vernier validity is checked. Initialization and updating are only performed when the check passes, the set period and low speed conditions are met.

[0010] Preferably, the process for determining the specific relationship between the motor angle and the steering wheel angle is as follows: Based on the number of motor rotations r, the current actual motor angle x, and the initial position x_0, calculate the continuously changing theoretical value of the motor angle Theta: Theta =(360-x_0)+(r-1)*360 +x; Based on the selected motor, a specific relationship is determined between the steering wheel rotation angle and the corresponding motor angle. The steering wheel angle is then calculated based on the motor angle. A rough diagram illustrating this specific relationship can be found below. Figure 2 .

[0011] Preferably, the angle verification analysis in step 2 includes: The Angle_S calculated by the Angle Calculation_S module and the Angle_P calculated by the Angle Calculation_P module are cross-validated. If the angle difference is within the error range, the Angle_S and Angle_P are considered to have passed the verification. When the cursor is available, Angle_S and Angle_P are verified against the angle calculated by the cursor, Angle_Vernier. If the angle difference is within the error range, it is determined that Angle_S and Angle_P have passed the verification with Angle_Vernier. Angle_MPS is verified along with Angle_S, Angle_P, and Angle_Vernier respectively. If the angle difference is within the error range, the verification is deemed to have passed. During normal operation, if a signal is lost, such as if PWM_P is lost, the Angle_P calculated by the angle calculation_P module is unreliable. In this case, after verifying the Angle_S signal and the Angle_Vernier signal, in order to further ensure the reliability of the output angle, the Angle_MPS calculated by the motor angle conversion calculation module is verified with Angle_S and Angle_Vernier respectively. If the angle difference is within the specified error range, the angle signal is considered reliable. If Angle_S, Angle_Vernier, and Angle_MPS pass the verification, the average of the three angles is taken as the angle information Angle_Out output through the angle output calculation module. During normal operation, if there is no signal loss, Angle_S, Angle_P, and Angle_Vernier will pass the verification. At this time, Angle_MPS acts as an arbitrator, verifying with the three angles respectively. Based on the difference, it determines which of the four angle signals are closer, obtains the verification result, and determines the output method. Through the angle output calculation module, it calculates the average angle that is closer to the actual value, and obtains the safe angle information Angle_Out. During normal operation, if all signal verifications fail, the angle output default value is 65535. Other user units, based on the obtained default value of 65535, trigger the error handling mechanism, disable functions related to the angle signal, calculate or execute other safety strategies, and enter a safe state according to the actual situation.

[0012] Preferably, the safety monitoring layer of the steering control unit estimates the angle and calculates a reasonable range of allowable angle output based on vehicle speed, lateral acceleration, the ratio coefficient of steering wheel to front wheel angle, and wheelbase information. R ≈ L / sin(β); Where β represents the front wheel steering angle and L represents the wheelbase; β = θ / k; Where k represents the proportionality coefficient between the steering wheel and the front wheel turning angle, and θ represents the steering wheel turning angle; a=V 2 *sin(θ / k) / L; Where a represents lateral acceleration and V represents vehicle speed; Based on the three formulas, θ = k*arcsin(a*L / V) 2 This allows for the estimation of a reasonable range of permissible steering wheel angle output.

[0013] Preferably, the angle information Angle_Out output by the function implementation layer of the steering control unit is compared with the reasonable range of the estimated steering wheel angle allowable output to determine whether the output of the function implementation layer is within the allowable range; if the actual output value exceeds the reasonable range, the error handling mechanism is triggered, the relevant functions calculated based on the steering angle are closed or other safety strategies are executed, and the system enters a safe state according to the actual situation.

[0014] The present invention has the following advantages: This invention verifies the PWM_S and PWM_P signals output by the angle calculation module, verifies the PWM_P and PWM_S signals with the vernier angle, and verifies the angle signal converted from the motor angle with the PWM_P, PWM_S, and vernier angle. Simultaneously, the safety monitoring layer estimates the steering wheel angle range based on vehicle speed, lateral acceleration, wheelbase, and the proportional coefficient between the steering wheel and front wheel angles. This estimated angle range is used to monitor the angle output by the functional implementation layer. If the safety monitoring layer detects low reliability of the functional implementation layer, an error handling mechanism is triggered, and the system enters a safe state based on the actual situation. Compared with existing technologies, this invention performs multiple safety verifications on the steering wheel angle of the vehicle steering system, greatly avoiding the hazards caused by angle failures during steering system operation, improving the overall angle safety of the steering system, and providing drivers with a safer driving experience. Attached Figure Description

[0015] Figure 1 This invention provides a block diagram for verifying steering wheel angle signals. Figure 2 This is a schematic diagram illustrating the specific relationship between the motor angle and the steering wheel angle provided by the present invention. Detailed Implementation

[0016] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] like Figure 1 As shown, this embodiment provides a method for verifying steering wheel angle signals based on motor rotor position signals, comprising the following steps: Step 1: The PWM angle signal and motor angle signal collected by the function implementation layer of the steering control unit are used for dual-channel motor signal verification; Step 2: Perform angle calculation based on PWM rotation angle signal and motor angle signal: The vernier algorithm obtains the absolute position of the initial position and the current angle, and then the motor angle is converted and calculated according to the angle calculation_S module and the angle calculation_P module. The calculated angle is verified and analyzed, and the steering wheel angle is output. Step 3: The safety monitoring layer of the steering control unit estimates the steering angle range based on vehicle speed, lateral acceleration, the ratio coefficient of steering wheel to front wheel angle, and wheelbase. It then monitors the angle output using the steering angle range to determine whether the error handling mechanism needs to be activated, and enters a safe state or normal operation.

[0018] In one exemplary instance, the functional implementation layer of the steering control unit acquires PWM angle signals through a TAS sensor (PWM version), the PWM angle signals including PWM_S and PWM_P, and acquires motor angle and speed signals through a position sensor (using a dual-redundant scheme); The angle calculation method in step 2 specifically includes: Based on the output signals PWM_S and PWM_P of the TAS sensor itself, a vernier operation is performed to initialize and update the absolute position signal of the current angle using the MPS absolute position signal to obtain the initial position signal. Based on the motor rotation angle signal output by the position sensor and the initial position signal calculated by the vernier, a motor angle conversion operation is performed to obtain approximate steering wheel angle information.

[0019] In one exemplary instance, the cursor algorithm in step 2 specifically includes: At low speeds, the vernier is calculated based on the output signals PWM_S and PWM_P from the TAS sensor to obtain the absolute position and effective vernier position of the current angle. The vernier difference is calculated based on PWM_P and PWM_S. A theoretical value is calculated based on the vernier difference at the Nth step. The difference is then compared with the actual value. If the deviation is greater than the threshold (25%) or the speed is too fast, the vernier reliability is considered low, and the vernier angle is not used for verification. The rotational speed is determined by the angular velocity converted from the motor speed. When the vernier is valid, the absolute position of the current angle is passed to the angle calculation_S module and the angle calculation_P module for further real-time angle calculation. The initial absolute position signal is then passed to the motor angle conversion calculation module as the initial position of the steering wheel.

[0020] In one exemplary instance, the angle calculation module _S determines the initial position of the current angle based on the absolute position of the current angle calculated by the cursor, and then calculates the real-time rotation angle information Angle_S that follows the PWM_S signal based on the PWM_S signal. The angle calculation module _P determines the initial position of the current angle based on the absolute position of the current angle calculated by the cursor, and then calculates the real-time rotation angle information Angle_P that follows the PWM_P signal based on the PWM_P signal.

[0021] In one exemplary instance, the motor angle conversion calculation in step 2 specifically includes: At low speeds, the vernier algorithm module calculates the initial absolute position and sends it to the motor angle conversion calculation module to determine the initial position of the motor angle and the initial position of the steering wheel. Subsequently, as the motor angle changes during operation, the motor angle is converted into an approximate steering wheel angle Angle_MPS through a specific relationship between the motor angle and the steering wheel angle.

[0022] In one exemplary instance, the vernier algorithm calculates the initial position to determine the initial position of the motor angle. Specifically, during the operation of the steering control unit, the initial position is periodically updated and the vernier validity is checked. Initialization and updating are only performed when the check passes, the set period is met, and the low-speed condition is satisfied.

[0023] In one exemplary instance, the process for determining a specific relationship between the motor angle and the steering wheel angle is as follows: Based on the number of motor rotations r, the current actual motor angle x, and the initial position x_0, calculate the continuously changing theoretical value of the motor angle Theta: Theta =(360-x_0)+(r-1)*360 +x; Based on the selected motor, a specific relationship is determined between the steering wheel rotation angle and the corresponding motor angle. The steering wheel angle is then calculated based on the motor angle. A rough diagram illustrating this specific relationship can be found below. Figure 2 The number of revolutions of the motor divided by the transmission ratio of the system gives the corresponding number of revolutions of the steering wheel. In other words, the number of revolutions of the steering wheel can be obtained from the motor angle and the number of revolutions, and then the steering wheel angle can be calculated.

[0024] In one exemplary instance, step 2, the calculation of angle verification analysis, includes: The Angle_S calculated by the Angle Calculation_S module and the Angle_P calculated by the Angle Calculation_P module are cross-validated. If the angle difference is within the error range, the Angle_S and Angle_P are considered to have passed the verification. When the cursor is available, Angle_S and Angle_P are verified against the angle calculated by the cursor, Angle_Vernier. If the angle difference is within the error range, it is determined that Angle_S and Angle_P have passed the verification with Angle_Vernier. Angle_MPS is verified along with Angle_S, Angle_P, and Angle_Vernier respectively. If the angle difference is within the error range, the verification is deemed to have passed. During normal operation, if a signal is lost, such as if PWM_P is lost, the Angle_P calculated by the angle calculation_P module is unreliable. In this case, after verifying the Angle_S signal and the Angle_Vernier signal, in order to further ensure the reliability of the output angle, the Angle_MPS calculated by the motor angle conversion calculation module is verified with Angle_S and Angle_Vernier respectively. If the angle difference is within the specified error range, the angle signal is considered reliable. If Angle_S, Angle_Vernier, and Angle_MPS pass the verification, the average of the three angles is taken as the angle information Angle_Out output through the angle output calculation module. During normal operation, if there is no signal loss, Angle_S, Angle_P, and Angle_Vernier will pass the verification. At this time, Angle_MPS acts as an arbitrator, verifying with the three angles respectively. Based on the difference, it determines which of the four angle signals are closer, obtains the verification result, and determines the output method. Through the angle output calculation module, it calculates the average angle that is closer to the actual value, and obtains the safe angle information Angle_Out. During normal operation, if all signal verifications fail, the angle output default value is 65535. Other user units, based on the obtained default value of 65535, trigger the error handling mechanism, disable functions related to the angle signal, calculate or execute other safety strategies, and enter a safe state according to the actual situation.

[0025] In one exemplary instance, the safety monitoring layer of the steering control unit estimates the angle and calculates a reasonable range of allowable angle output based on vehicle speed, lateral acceleration, the ratio of steering wheel to front wheel angle, and wheelbase information. R ≈ L / sin(β); Where β represents the front wheel steering angle and L represents the wheelbase; β = θ / k; Where k represents the proportionality coefficient between the steering wheel and the front wheel turning angle, and θ represents the steering wheel turning angle; a=V 2 *sin(θ / k) / L; Where a represents lateral acceleration and V represents vehicle speed; Based on the three formulas, θ = k*arcsin(a*L / V) 2 This allows for the estimation of a reasonable range of permissible steering wheel angle output.

[0026] In one exemplary instance, the angle information Angle_Out output by the function implementation layer of the steering control unit is compared with the reasonable range of the estimated steering wheel angle that can be output to determine whether the output of the function implementation layer is within the allowable range. If the actual output value exceeds the reasonable range, an error handling mechanism is triggered to close the relevant functions calculated based on the steering angle or to execute other safety strategies, and to enter a safe state according to the actual situation.

[0027] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for verifying steering wheel angle signals based on motor rotor position signals, characterized in that: Includes the following steps: Step 1: The function implementation layer of the steering control unit acquires the PWM angle signal output by the TAS sensor and the motor angle signal output by the motor position sensor MPS, and performs dual-channel motor signal verification on the motor angle signal; the PWM angle signal includes two signals: PWM_S and PWM_P. Step 2: Perform angle calculation based on PWM rotation angle signal and motor angle signal: The two signals PWM_S and PWM_P are used to obtain the current absolute position of the angle through a vernier algorithm. The current absolute position of the angle is then sent to the angle calculation_S module and the angle calculation_P module to obtain the real-time rotation angles Angle_S and Angle_P. The obtained current angle absolute position signal is initialized and updated using MPS absolute position signal to obtain the initial position signal; the motor angle conversion operation is performed based on the initial position signal and the motor angle signal to obtain the approximate steering wheel angle information Angle_MPS; After mutual verification of Angle_S and Angle_P, the initial position signal and motor angle signal are sent to the motor angle conversion calculation module to perform motor angle conversion calculation, and the approximate steering wheel angle information Angle_MPS is obtained. The calculated angle verification analysis is performed on Angle_S, Angle_P, and the vernier calculated angles Angle_Vernier and Angle_MPS output by the vernier algorithm, and the steering wheel angle Angle_Out is finally output. The cursor algorithm specifically includes: At low speeds, vernier calculations are performed based on the TAS sensor output signals PWM_S and PWM_P to obtain the current absolute position and valid vernier bit. The vernier difference is calculated based on PWM_P and PWM_S. A theoretical value is calculated based on the vernier difference at the Nth step, and this difference is compared with the actual value. If the deviation exceeds a threshold of 25% or the speed exceeds 500° / s, the speed is determined using the angular velocity converted from motor speed. If the vernier reliability is deemed low, the vernier angle is not used for verification. When the vernier is reliable, the current absolute position of the vernier angle is sent to the angle calculation_S module and the angle calculation_P module respectively for real-time angle calculation, including: The angle calculation module _S determines the initial absolute position based on the current absolute position of the cursor calculation, and then calculates the real-time rotation angle information Angle_S that follows the PWM_S signal based on the PWM_S signal. The angle calculation module _P determines the initial absolute position based on the current absolute position calculated by the cursor, and then calculates the real-time rotation angle information Angle_P that follows the PWM_P signal based on the PWM_P signal. The analysis from a computational perspective includes: The Angle_S calculated by the Angle Calculation_S module and the Angle_P calculated by the Angle Calculation_P module are cross-validated. If the angle difference is within the error range, the Angle_S and Angle_P are considered to have passed the verification. When the cursor is available, Angle_S and Angle_P are verified against the angle calculated by the cursor, Angle_Vernier. If the angle difference is within the error range, it is determined that Angle_S and Angle_P have passed the verification with Angle_Vernier. Angle_MPS is verified along with Angle_S, Angle_P, and Angle_Vernier respectively. If the angle difference is within the error range, the verification is deemed to have passed. If Angle_S, Angle_Vernier, and Angle_MPS pass the verification, the average of the three angles is taken as the steering wheel angle Angle_Out output through the angle output calculation module. During normal operation, if there is no signal loss, Angle_S, Angle_P, and Angle_Vernier will pass the verification. At this time, Angle_MPS acts as an arbitrator, verifying with the three angles respectively. Based on the difference, it determines which of the four angle signals is closer, obtains the verification result, and determines the output method. The angle output calculation module calculates the average angle that is closer to the actual value, and obtains the steering wheel angle Angle_Out. Step 3: The safety monitoring layer of the steering control unit estimates the steering angle range based on vehicle speed, lateral acceleration, the ratio coefficient of steering wheel to front wheel angle, and wheelbase. It then compares the steering angle range with the output Angle_Out to monitor the angle output and determine whether to enable the error handling mechanism, enter a safe state, or operate normally.

2. The method for verifying steering wheel angle signals based on motor rotor position signals according to claim 1, characterized in that: The process for determining the specific relationship between the motor angle and the steering wheel angle is as follows: Based on the number of motor rotations r, the current actual motor angle x, and the initial position x_0, calculate the continuously changing theoretical value of the motor angle Theta: Theta =(360-x_0)+(r-1)*360 +x; Based on the specific motor selected, a specific relationship is determined between the steering wheel angle and the corresponding motor angle, and the steering wheel angle is calculated based on the motor angle.

3. The method for verifying steering wheel angle signals based on motor rotor position signals according to claim 1, characterized in that: The safety monitoring layer of the steering control unit estimates the steering angle based on vehicle speed, lateral acceleration, the ratio coefficient of steering wheel to front wheel angle, and wheelbase information to calculate the reasonable range of allowable steering wheel angle output, i.e., the steering angle range. R ≈ L / sin(β); Where β represents the front wheel steering angle and L represents the wheelbase; β = θ / k; Where k represents the proportionality coefficient between the steering wheel and the front wheel turning angle, and θ represents the steering wheel turning angle; a=V 2 *sin(θ / k) / L; Where a represents lateral acceleration and V represents vehicle speed; Based on the three formulas, θ = k*arcsin(a*L / V) 2 This allows for the estimation of a reasonable range of permissible steering wheel angle output.

4. The method for verifying steering wheel angle signal based on motor rotor position signal according to claim 3, characterized in that: The steering control unit's function implementation layer outputs the steering wheel angle Angle_Out and compares it with the reasonable range of the estimated allowable steering wheel angle output to determine whether the output of the function implementation layer is within the allowable range. If the actual output value exceeds the reasonable range, the error handling mechanism is triggered, the relevant functions calculated based on the steering angle are closed or other safety strategies are executed, and the system enters a safe state according to the actual situation.

5. The method for verifying steering wheel angle signal based on motor rotor position signal according to claim 1, characterized in that: During normal operation, if a signal is lost, such as PWM_P, the Angle_P calculated by the angle calculation_P module is unreliable. In this case, after verifying the Angle_S signal and the Angle_Vernier signal, in order to further ensure the reliability of the output angle, the Angle_MPS calculated by the motor angle conversion calculation module is verified with Angle_S and Angle_Vernier respectively. If the angle difference is within the specified error range, the angle signal is considered reliable.

6. The method for verifying steering wheel angle signal based on motor rotor position signal according to claim 1, characterized in that: During normal operation, if all signal verifications fail, the angle outputs a default value. Other user units then trigger an error handling mechanism based on the obtained default value, disabling functions related to the angle signal calculation or executing other safety strategies, and entering a safe state as needed.

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