Verification mode for real vehicle torque threshold value of electric power steering system

Abstract

The invention discloses an electric power steering system real vehicle torque threshold verification method, which relates to the field of automobile part tests and comprises a micro-control unit, a torque sensor, a temperature sensor, a CAN transceiver, a power management module, a motor driving module, a whole vehicle network system, a whole vehicle power supply system and a motor. When the method is used, on the basis of internal calculation logic of the power-assisted torque, the jump state machine is added, the torque maximum value can be obtained through abnormal torque calculation, after the maximum torque value is output, the influence of the maximum torque value on a real vehicle can be verified, and the torque steering wheel is connected with the steering wheel; through a specific coordinate system formed by a real vehicle steering wheel and moment steering wheels, angles of two ends of a rotating shaft can be calculated through two-phase sine output of an encoder of each moment steering wheel, then torque is calculated through intersection of the two angles, the torque is a real torque value of a real vehicle, and the maximum output of the EPS can be determined through the real vehicle torque value. The influence on a real vehicle is reduced.

Description

Technical Field

[0001] The invention relates to the field of automobile parts testing, and in particular to a method for verifying a torque threshold value of an actual vehicle of an electric power steering system. Background Art

[0002] Car steering wheel torque refers to the moment applied by the driver when turning the steering wheel. Torque is the product of force and distance, usually expressed in Newton meters. The electric power steering system, abbreviated as EPS, is a power steering system that directly relies on the motor to provide auxiliary torque. The measurement of steering wheel torque is very important for evaluating the vehicle's handling and driving comfort. The current torque verification method usually adopts the bench verification method to simulate the actual vehicle load and obtain the current EPS torque output capacity through the EPS external torque value.

[0003] However, since it is a bench simulation, it cannot accurately simulate various working conditions of the actual vehicle. In addition, after the actual vehicle signal is transmitted to EPS, EPS has a certain verification and anti-error function. There is no way to verify the design capability of the maximum torque value, and it cannot ensure whether the steering wheel's own execution in an unexpected situation will affect the driver. Therefore, a method for verifying the torque threshold of an actual vehicle of an electric power steering system is urgently needed. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that the existing bench verification method cannot accurately simulate various working conditions of the actual vehicle because it is a bench simulation, and after the actual vehicle signal is transmitted to the EPS, the EPS has a certain verification and anti-error function, and there is no way to verify the design capability of the maximum torque value. It cannot ensure whether the steering wheel's own execution in an unexpected situation will affect the driver. A method for verifying the torque threshold of an actual vehicle of an electric power steering system is provided.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a method for verifying the torque threshold of an actual vehicle of an electric power steering system, the verification method comprising: a microcontroller unit, a torque sensor, a temperature sensor, a CAN transceiver, a power management module, a motor drive module, a whole vehicle network system, a whole vehicle power system, and a motor.

[0006] Preferably, the CAN transceiver transmits signals with the vehicle network system, the power management module is electrically connected to the CAN transceiver and the microcontroller unit, and the vehicle power system is electrically connected to the power management module and the motor drive module.

[0007] Preferably, the CAN transceiver and the motor drive module both transmit signals bidirectionally with the micro control unit, the torque sensor, the temperature sensor, the motor and the micro control unit transmit signals unidirectionally, and the motor drive module transmits signals unidirectionally with the motor.

[0008] Preferably, a transmission mechanism assembly is provided at the output end of the motor, and the transmission mechanism assembly is mechanically linked to the steering wheel, the steering column and the wheel.

[0009] Preferably, the micro control unit includes a power assist calculation, and the power assist calculation relies on vehicle-side signal input, and the vehicle-side signal is collected by vehicle-related sensors.

[0010] Preferably, the microcontroller unit calculates: Step 1: Vehicle side signals, vehicle speed, wheel speed, acceleration, and yaw rate are used to determine straight-ahead travel; Step 2: Determine non-steering straight driving based on hand force torque, steering speed, and motor rotation angle; Step 3: The calculation of the assist torque will begin only after steps 1 and 2 are met simultaneously and last for 0.09 seconds.

[0011] Preferably, the vehicle speed, wheel speed, acceleration, yaw angular velocity in the vehicle side signal and the motor torque of the motor sensor are used to perform straight driving judgment, and the straight driving judgment includes straight driving and non-straight driving. The torque of the torque sensor is used to perform non-steering judgment, and the non-steering judgment includes steering and non-steering. The straight driving judgment and non-steering judgment are used to calculate the steering angle, and the steering angle data is added to the power assist torque calculation.

[0012] Preferably, a jump state machine is added based on the internal calculation logic of the assist torque, including: Step 1: Whether the torque is calculated normally. When not triggered, it is a normal auxiliary torque calculation. First, frequency division is performed, including high-frequency calculation and low-frequency calculation, then threshold calculation is performed, and finally filtering compensation is performed. When triggered, the constant value of the torque is directly input, and the constant value is the maximum torque value during design. Step 2: After EPS outputs the maximum torque value on the actual vehicle side, in order to verify the impact of the maximum torque value on the actual vehicle, a torque steering wheel is connected to the steering wheel. Through the specific coordinate system formed by the actual vehicle steering wheel and the torque steering wheel, the two-phase sinusoidal output of the encoder of each torque steering wheel can be used to calculate the angles at both ends of the shaft, and then the torque is calculated from the intersection of the two angles. This is the true torque value of the actual vehicle. The torque value of the actual vehicle can be used to determine the impact on the actual vehicle under the maximum output of EPS.

[0013] Compared with the prior art, the present invention has the following beneficial effects: When the present invention is used, a jump state machine is added on the basis of the internal calculation logic of the power-assisted torque, and the abnormal torque calculation can obtain the maximum torque value. After the maximum torque value is output, the influence of the maximum torque value on the actual vehicle can be verified. The torque steering wheel is connected to the steering wheel, and a specific coordinate system is formed by the actual vehicle steering wheel and the torque steering wheel. The two-phase sinusoidal outputs of the encoder of each torque steering wheel can be used to calculate the angles at both ends of the rotating shaft, and then the torque is calculated by the intersection of the two angles, which is the real torque value of the actual vehicle. The torque value of the actual vehicle can be used to determine the influence on the actual vehicle under the maximum output of EPS. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic structural diagram of the electric power steering system of the present invention; Figure 2 A schematic diagram of the calculation steps of the microcontroller unit of the present invention; Figure 3 It is a schematic diagram of the straight-line determination of the present invention; Figure 4 It is a schematic diagram of the assist torque calculation steps of the present invention. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] See also Figure 1-Figure 4 A method for verifying the torque threshold of an electric power steering system in a real vehicle, the verification method comprising: a microcontroller unit, a torque sensor, a temperature sensor, a CAN transceiver, a power management module, a motor drive module, a vehicle network system, a vehicle power system, and a motor.

[0017] Example 1 As a preferred embodiment of the present invention: the CAN transceiver transmits signals with the vehicle network system, the power management module is electrically connected with the CAN transceiver and the micro control unit, and the vehicle power system is electrically connected with the power management module and the motor drive module; The main function of the CAN transceiver is to convert the data provided by the CAN controller into electrical signals and send and receive data through the data bus. The vehicle network system collects, stores and sends all working conditions and static and dynamic information of the vehicle. The power management module includes monitoring and managing the vehicle's power system to ensure the normal operation of the vehicle and extend the battery life. The power management module realizes comprehensive control of the vehicle's power system by monitoring the status of the battery, adjusting the generator output voltage, and managing the power load.

[0018] Example 2 As a preferred embodiment of the present invention: the CAN transceiver and the motor drive module both transmit signals bidirectionally with the microcontroller unit, the torque sensor, the temperature sensor, the motor and the microcontroller unit transmit signals unidirectionally, and the motor drive module transmits signals unidirectionally with the motor; The microcontroller collects data from the vehicle steering system through torque sensors and temperature sensors, and uses algorithms to calculate the required power assist value to achieve optimized control of the vehicle power system. The torque sensor monitors the torque and speed changes of the motor in real time, and transmits the data to the host computer for recording and analysis. The temperature sensor is used to detect the operating temperature of the motor, transmission assembly, steering wheel and steering column in the vehicle steering system. The microcontroller transmits the drive signal to the motor drive module, and the motor drive module controls the motor operation through signal transmission.

[0019] Example 3 As a preferred embodiment of the present invention: a transmission mechanism assembly is provided at the output end of the motor, and the transmission mechanism assembly is mechanically linked with the steering wheel, the steering column and the wheel; The core function of the motor drive module is to convert electrical energy into mechanical energy, and drive the vehicle by controlling the transmission mechanism assembly, steering wheel, steering column and wheels.

[0020] Example 4 As a preferred embodiment of the present invention: the micro control unit includes a power assist calculation, and the power assist calculation relies on a vehicle-side signal input, and the vehicle-side signal is collected by a vehicle-related sensor; The calculation of the microcontroller unit also includes power assist calculation, return calculation, damping calculation, etc. Among them, the power assist calculation has the greatest impact on the torque, and the impact of the return calculation, damping calculation, etc. on the torque is negligible. Therefore, it is necessary to interfere with the power assist calculation to obtain the maximum torque.

[0021] Example 5 As a preferred embodiment of the present invention: microcontroller unit calculation method: Step 1: Vehicle side signals, vehicle speed, wheel speed, acceleration, and yaw rate are used to determine straight-ahead travel; Step 2: Determine non-steering straight driving based on hand force torque, steering speed, and motor rotation angle; Step 3: When both step 1 and step 2 are met and last for 0.09s, the calculation of the assist torque will begin; First, the straight-ahead determination is made through vehicle side signals, vehicle speed, wheel speed, acceleration, and yaw angular velocity. After the determination, if it is not straight-ahead, the process returns to the beginning and the straight-ahead determination is made again. If it is straight-ahead, the process proceeds to the following step to determine whether it is non-steering straight-ahead based on hand force torque, steering speed, and motor rotation angle. If it is not non-steering straight-ahead, the process returns to the straight-ahead determination step. If it is non-steering straight-ahead, and both step one and step two are satisfied and last for 0.09 seconds, the process proceeds to the next step to calculate the power assist.

[0022] Example 6 As a preferred embodiment of the present invention: the vehicle speed, wheel speed, acceleration, yaw rate and motor torque of the motor sensor in the vehicle side signal are used to determine the straight-ahead movement, and the straight-ahead movement determination includes straight-ahead movement and non-straight-ahead movement. The torque of the torque sensor is used to determine the non-steering movement, and the non-steering movement determination includes steering and non-steering. The straight-ahead movement determination and the non-steering determination are used to calculate the steering angle, and the steering angle data is added to the calculation of the power-assist torque. The yaw rate is the angular velocity of the car's mass rotating around the z-axis (car coordinate system). The yaw rate of the car reflects the severity of the car's turn. When the car's center of mass slip angle is not too large, it also reflects the car's running trajectory. The judgment of the car's steering performance mainly includes the evaluation of steering force, straightness, roll feeling and turning performance. Steering force refers to the force required to operate the steering wheel. The evaluation content includes the size and change of steering force when stationary and low-speed driving, as well as the steering force when driving at extremely low speeds to 60km / h on ordinary roads or curved roads. A moderate force and an appropriate sense of resistance indicate good steering performance; straightness evaluation includes alignment, stability, yaw and ease of steering correction, which evaluate the vehicle's stability and steering sensitivity when driving in a straight line; ROLL sense evaluates the vehicle's ROLL size, speed, convergence and front and rear coordination during sharp steering, which is tested by conducting a snaking evaluation at a speed of 100-120km / h on a straight highway; turning performance mainly evaluates the vehicle's turning performance, including steering sensitivity and vehicle responsiveness when turning.

[0023] Example 7 As a preferred embodiment of the present invention: based on the internal calculation logic of the assist torque, a jump state machine is added, including: Step 1: Whether the torque is calculated normally. When not triggered, it is a normal auxiliary torque calculation. First, frequency division is performed, including high-frequency calculation and low-frequency calculation, then threshold calculation is performed, and finally filtering compensation is performed. When triggered, the constant value of the torque is directly input, and the constant value is the maximum torque value during design. Step 2: After EPS outputs the maximum torque value on the actual vehicle side, in order to verify the impact of the maximum torque value on the actual vehicle, a torque steering wheel is connected to the steering wheel. Through the specific coordinate system formed by the actual vehicle steering wheel and the torque steering wheel, the two-phase sinusoidal output of the encoder of each torque steering wheel can be used to calculate the angles at both ends of the shaft, and then the torque is calculated from the intersection of the two angles, which is the real torque value of the actual vehicle. The impact on the actual vehicle under the maximum output of EPS can be determined through the torque value of the actual vehicle; Assist torque, also known as torsional torque, is an indicator that measures the torque generated when a car engine or electric motor rotates. It indicates the size of the force that a car can generate within a certain period of time and the direction of the force. Assist torque is mainly reflected in starting and accelerating, climbing, high-speed driving, power transmission, etc. Based on the internal calculation logic of the assist torque, a jump state machine is added. Normal torque calculation can be filtered and compensated through frequency division calculation and threshold calculation. Abnormal torque calculation can obtain the maximum torque value. After the maximum torque value is output, the impact of the maximum torque value on the actual vehicle can be verified.

[0024] Working principle: When the present invention is used, it first determines whether the vehicle is going straight by using the vehicle side signal, vehicle speed, wheel speed, acceleration, and yaw angular velocity. After the determination, if it is not going straight, it returns to the beginning and determines whether it is going straight again. If it is going straight, it performs the following steps to determine whether it is not turning straight, using the hand force torque, steering speed, and motor rotation angle to determine whether it is going straight without steering. If it is not going straight without steering, it returns to the step of determining whether it is going straight without steering, and both step one and step two are satisfied at the same time, and it lasts for 0.09s, it proceeds to the next step to perform power assist calculation. Based on the internal calculation logic of the power assist torque, a jump state machine is added to determine whether the torque is calculated normally. If it is not triggered, it is a normal power assist torque meter. Calculation, then first perform frequency division, including high-frequency calculation, low-frequency calculation, then perform threshold calculation, and finally perform filtering compensation. When triggering, directly input the constant value of the torque, the constant value is the maximum torque value during design. After EPS outputs the maximum torque value on the actual vehicle side, in order to verify the influence of the maximum torque value on the actual vehicle, a torque steering wheel is connected to the steering wheel, and a specific coordinate system is formed by the actual vehicle steering wheel and the torque steering wheel. The two-phase sinusoidal output of the encoder of each torque steering wheel can be used to calculate the angles at both ends of the shaft, and then the torque is calculated from the intersection of the two angles, which is the real torque value of the actual vehicle. The torque value of the actual vehicle can be used to determine the influence on the actual vehicle under the maximum output of EPS.

[0025] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A method for verifying the torque threshold of an electric power steering system, characterized in that: The verification method includes: a microcontroller unit, a torque sensor, a temperature sensor, a CAN transceiver, a power management module, a motor drive module, a vehicle network system, a vehicle power system, and a motor.

2. A method for verifying the torque threshold of an electric power steering system according to claim 1, characterized in that: The CAN transceiver transmits signals with the vehicle network system, the power management module is electrically connected to the CAN transceiver and the micro control unit, and the vehicle power system is electrically connected to the power management module and the motor drive module.

3. The method for verifying the torque threshold of an electric power steering system according to claim 1, characterized in that: The CAN transceiver and the motor drive module both transmit signals bidirectionally with the micro control unit, the torque sensor, the temperature sensor, the motor and the micro control unit transmit signals unidirectionally, and the motor drive module transmits signals unidirectionally with the motor.

4. The method for verifying the torque threshold of an electric power steering system according to claim 1, characterized in that: The output end of the motor is provided with a transmission mechanism assembly, and the transmission mechanism assembly is mechanically linked with the steering wheel, the steering column and the wheel.

5. The method for verifying the torque threshold of an electric power steering system according to claim 1, characterized in that: The micro control unit includes a power assist calculation, and the power assist calculation relies on vehicle-side signal input, and the vehicle-side signal is collected by vehicle-related sensors.

6. A method for verifying the torque threshold of an electric power steering system according to claim 5, characterized in that: The microcontroller unit calculates: Step 1: Vehicle side signals, vehicle speed, wheel speed, acceleration, and yaw rate are used to determine straight-ahead travel; Step 2: Determine non-steering straight driving based on hand force torque, steering speed, and motor rotation angle; Step 3: The calculation of the assist torque will begin only after steps 1 and 2 are met simultaneously and last for 0.09 seconds.

7. A method for verifying the torque threshold of an electric power steering system according to claim 6, characterized in that: The vehicle speed, wheel speed, acceleration, yaw angular velocity in the vehicle side signal and the motor torque of the motor sensor are used to perform a straight-ahead judgment, and the straight-ahead judgment includes straight-ahead and non-straight-ahead. The torque of the torque sensor is used to perform a non-steering judgment, and the non-steering judgment includes steering and non-steering. The straight-ahead judgment and the non-steering judgment are used to calculate the steering angle, and the steering angle data is added to the power-assist torque calculation.

8. The method for verifying the torque threshold of an electric power steering system according to claim 7, characterized in that: Based on the internal calculation logic of the assist torque, a jump state machine is added, including: Step 1: Whether the torque is calculated normally. When not triggered, it is a normal auxiliary torque calculation. First, frequency division is performed, including high-frequency calculation and low-frequency calculation, then threshold calculation is performed, and finally filtering compensation is performed. When triggered, the constant value of the torque is directly input, and the constant value is the maximum torque value during design. Step 2: After EPS outputs the maximum torque value on the actual vehicle side, in order to verify the impact of the maximum torque value on the actual vehicle, a torque steering wheel is connected to the steering wheel. Through the specific coordinate system formed by the actual vehicle steering wheel and the torque steering wheel, the two-phase sinusoidal output of the encoder of each torque steering wheel can be used to calculate the angles at both ends of the shaft, and then the torque is calculated from the intersection of the two angles. This is the true torque value of the actual vehicle. The torque value of the actual vehicle can be used to determine the impact on the actual vehicle under the maximum output of EPS.

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