Bench test method and device for active rear wheel steering device

Abstract

The present invention relates to a bench test method and device for an active rear-wheel steering device. The test is conducted on a rear-wheel steering multi-physics-in-the-loop test bench, which includes an ARS sample, a left linear actuator, a right linear actuator, a test bench controller, a fixture, and a fixing device. The test consists of three parts: a low-speed steering flexibility test, a steering wheel angle step test, and a steering wheel angle periodic change sensitivity stability test. The present invention uses an actual ARS sample, and utilizes the rack displacement output by the ARS sample as the left and right rear steering rod displacements required by the vehicle dynamics module; uses a double-sided linear actuator to simulate the rear-wheel steering rod load of an actual vehicle through force control, which more accurately reflects the actual vehicle working conditions; the present invention designs a series of test cases, which more comprehensively evaluates the vehicle performance indicators that need to be evaluated for active rear-wheel steering, such as turning radius, center of mass sideslip angle, and yaw angular velocity, in multiple dimensions.

Description

Technical Field

[0001] The invention belongs to the technical field of chassis system testing, and in particular relates to a bench testing method and device for an active rear wheel steering device. Background Art

[0002] With the advancement of automotive chassis electronic control systems and autonomous driving technology, more and more vehicles are equipped with active rear-wheel steering (ARS). Integrated with the front-wheel steering, ARS reduces the vehicle's turning radius during low-speed turns, improving maneuverability. It also maintains a near-zero sideslip angle during high-speed turns, enhancing the vehicle's dynamic response to steering wheel angle input and handling stability. ARS prototypes undergo multi-physics-in-the-loop (MIL) bench testing in a full-vehicle network environment to proactively verify the performance of active rear-wheel steering control.

[0003] Existing testing methods use dual-sided spring loads instead of dual-sided linear actuators to simulate the load on the rear steering rod of a real vehicle. However, the spring load's deformation and spring force have a constant linear relationship, while the displacement and load of the rear steering rod of a real vehicle do not have a constant linear relationship. Therefore, this method cannot fully simulate the conditions of a real vehicle. Summary of the Invention

[0004] The present invention aims to provide a bench test method for active rear-wheel steering systems and a multi-physics-in-the-loop test bench for rear-wheel steering, addressing the inability of existing testing methods to fully simulate actual vehicle conditions. This invention uses dual-sided linear actuators to simulate the rear-wheel steering tie rod loads of actual vehicles, accurately reflecting actual vehicle operating conditions.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A bench test method for an active rear wheel steering device includes the following steps: A. Low-speed steering flexibility test

[0007] A1. Set the power supply pressure, vehicle speed, and path of the ARS prototype. Increase the steering wheel angle to the maximum positive value. After the vehicle drives a circle at a constant speed, calculate the vehicle's turning radius R1.

[0008] A2. Adjust the power supply pressure of the ARS sample and calculate the vehicle's turning radius R2;

[0009] A3. Calculate the vehicle's turning radius optimization rate ΔR1, where ΔR1 = (R1 - R2) / R2;

[0010] A4. Maintaining the voltage and vehicle speed constant, increase the steering wheel angle to its maximum positive value. Collect the front and rear wheel angles to form a front-wheel angle-rear wheel angle curve, and calculate the proportional relationship between the front and rear wheel angles.

[0011] A5. If ΔR1>2, the turning radius reduction capability of ARS is significantly improved compared to front-wheel steering only, but not otherwise;

[0012] B. Steering wheel angle step test

[0013] B1. Set the ARS prototype's power supply pressure, vehicle speed, and path. Gradually increase the vehicle's steering wheel angle until the vehicle's lateral acceleration reaches a certain value. Maintain the current steering wheel angle. After the vehicle travels a circle at a constant speed, increase the steering wheel angle and calculate the vehicle's maximum sideslip angle β1.

[0014] When the steering wheel angle increases to a specific value, the current time is set to t1. When the vehicle yaw rate reaches 90% of its steady-state value γ1 for the first time, the current time is set to t2. The vehicle yaw rate reaction time t3 is calculated, t3 = t2 - t1.

[0015] The maximum yaw rate of the vehicle during the acquisition period γ2 is used to calculate the vehicle yaw rate overshoot γ3, γ3 = (γ2-γ1) / γ1;

[0016] B2. Adjust the power supply pressure of the ARS sample and calculate the vehicle's maximum center of mass sideslip angle β2, vehicle yaw rate response time t4, and vehicle yaw rate overshoot γ4 during the calculation period.

[0017] B3. Calculate the maximum fluctuation of the center of mass sideslip angle Δβ1 when the ARS is activated, where Δβ1 = β2. Calculate the yaw rate followability Δt1 when the ARS is activated, where Δt1 = t4, and the yaw rate followability optimization rate Δt2 when the ARS is activated, where Δt2 = (t3 - t4) / t3. Calculate the yaw rate overshoot Δγ1 when the ARS is activated, where Δγ1 = γ4, and the yaw rate overshoot optimization rate Δγ2, where Δγ2 = γ3 - γ4.

[0018] B4. Determine whether the ARS's high-speed sideslip angle suppression capability and yaw rate tracking capability meet the requirements and whether the ARS's sideslip angle suppression capability and yaw rate tracking capability have improved;

[0019] C. Steering wheel angle periodic change sensitivity stability test

[0020] C1. Set the power supply pressure, vehicle speed control mode, and path of the ARS prototype. Control the vehicle steering wheel angle according to a sinusoidal curve. The steering wheel angle is subjected to a 10-cycle sinusoidal curve to form a center of mass sideslip angle-steering wheel angle curve and a yaw rate-steering wheel angle curve.

[0021] C2. Take the center of mass slip angle and yaw rate values ​​within the four steering wheel angle ranges within one steering wheel angle sinusoidal cycle. Calculate the center of mass slip angle sensitivity M within the four steering wheel angle ranges within one steering wheel angle sinusoidal cycle by fitting the least squares method. βi (i=1,2,…,10) and yaw rate sensitivity M γi (i=1,2,…,10); Calculate the center of mass side slip angle sensitivity stability ΔM β and yaw rate sensitivity stability ΔM γ :

[0022] C3. Determine whether the center of mass sideslip angle sensitivity stability and yaw rate sensitivity stability of the ARS meet the requirements.

[0023] Furthermore, in step A1, the power supply pressure of the ARS sample is 0V, the vehicle speed is 5km / h, the path is a 100m*100m square road with a road adhesion coefficient of 1.0, and the steering wheel angle is increased to the positive maximum value at a steering wheel angle change rate of 180deg / s.

[0024] Furthermore, in step A4, the steering wheel angle is increased to a positive maximum value at a steering wheel angle change rate of 10 deg / s, and at the same time, the front wheel angle and the rear wheel angle value are mapped one to one to form a front wheel angle-rear wheel angle curve.

[0025] Furthermore, in step B1, the power supply pressure of the ARS sample is 0V, the vehicle speed is 80km / h, the path is a 100m*100m square road with a road adhesion coefficient of 1.0, and the vehicle lateral acceleration reaches 3m / s 2 When the current steering wheel angle is kept unchanged, the steering wheel angle is increased to 90 degrees at a steering wheel angle change rate of 180 degrees per second and maintained for 10 seconds. At time t1, the steering wheel angle is 45 degrees.

[0026] Furthermore, step B4 specifically includes: If Δβ1 < 0.2 degrees, Δt1 < 0.1 seconds, and Δγ1 < 10%, then the ARS's high-speed slip angle suppression capability and yaw rate tracking capability meet the requirements; otherwise, they do not meet the requirements. If Δt2 > 50% and Δγ2 > 30%, then the ARS's slip angle suppression capability and yaw rate tracking capability are significantly improved compared to front-wheel steering only.

[0027] Furthermore, in step C1, the power supply pressure of the ARS sample is 12V, the vehicle speed is 80km / h, the path is a straight road with a road adhesion coefficient of 1.0 and a length of 10km, the period of the sine curve is 5s, and the amplitude value is the maximum lateral acceleration of the vehicle reaches 1m / s 2At the same moment, the center of mass sideslip angle and the steering wheel angle are mapped one by one to form a center of mass sideslip angle-steering wheel angle curve, and the yaw rate and the steering wheel angle are mapped one by one to form a yaw rate-steering wheel angle curve.

[0028] Further, in step C2, the four steering wheel angle ranges are: an amplitude of 20% of the steering wheel angle in a positive direction to an amplitude of 80% of the steering wheel angle in a positive direction, an amplitude of 80% of the steering wheel angle in a positive direction to an amplitude of 20% of the steering wheel angle in a positive direction, an amplitude of 20% of the steering wheel angle in a negative direction to an amplitude of 80% of the steering wheel angle in a negative direction, and an amplitude of 80% of the steering wheel angle in a negative direction to an amplitude of 20% of the steering wheel angle in a negative direction;

[0029] The slope K of the sideslip angle relative to the steering wheel angle βi1 , K βi2 , K βi3 , K βi4 The average value of the four is the center of mass side slip angle sensitivity M within a steering wheel angle sinusoidal cycle. βi (i=1,2,…,10); slope K of yaw rate relative to steering wheel angle γi1 , K γi2 , K γi3 , K γi4 The average value of the four is the yaw rate sensitivity M within a steering wheel angle sinusoidal cycle. γi (i=1,2,…,10); the variance of the center of mass sideslip angle sensitivity over 10 cycles is calculated as the center of mass sideslip angle sensitivity stability ΔM β The variance of the yaw rate sensitivity over 10 cycles is the yaw rate sensitivity stability ΔM γ .

[0030] Furthermore, step C3 is specifically as follows: if ΔM β <0.05 and ΔM γ <2, the center of mass sideslip angle sensitivity stability and yaw rate sensitivity stability of ARS meet the requirements, otherwise they do not meet the requirements.

[0031] A bench test device for an active rear wheel steering device, comprising an ARS sample, a left linear actuator, a right linear actuator, a test bench controller, and a fixing fixture and a fixing device for the ARS sample;

[0032] Among them, the test bench controller adopts a HIL simulator, including a driver operation and vehicle dynamics module, a test bench control module and a performance evaluation module; the left and right linear actuators are respectively connected to the left and right tie rod fork arms of the ARS sample, and the left and right linear actuators are integrated with force sensors and displacement sensors. The push rods of the left and right linear actuators can only perform linear reciprocating motion along the axis of the actuator.

[0033] Furthermore, the driver control and vehicle dynamics module sends the gear position, vehicle speed, steering wheel angle, steering wheel speed, longitudinal acceleration, lateral acceleration, and yaw angular velocity signals to the CAN, and sends the left rear steering rod force and the right rear steering rod force to the test bench control module; after signal conditioning such as filtering and direction conversion calculation processes, the test bench control module converts the left rear and right rear steering rod forces into target values ​​of the left and right linear actuator cylinder load forces and sends them to the left and right linear actuator cylinders, thereby controlling the push rods of the left and right linear actuator cylinders to perform linear motion in a force-controlled manner; the left and right linear actuator cylinders send the actual values ​​of the left and right linear actuator cylinder load forces to the test bench control module;

[0034] The ARS prototype controls the rear wheel steering angle by controlling the rack travel, so that the center of mass slip angle is as close as possible to the target value of 0; the ARS prototype rack pushes the push rods of the left and right linear actuators to perform linear motion, and the left and right linear actuator strokes are collected. The test bench control module converts them into the displacement of the left and right rear steering rods and sends them to the driver control and vehicle dynamics modules to achieve a closed-loop test;

[0035] The driver control and vehicle dynamics module sends signals such as the sideslip angle, front wheel turning angle, and rear wheel turning angle to the performance evaluation module, and the ARS sample sends signals such as the ARS working status, working current, and rack position to the performance evaluation module for performance evaluation.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The bench test method and device for the active rear-wheel steering device of the present invention use an actual ARS sample, and utilize the rack displacement output by it as the left and right rear steering rod displacements required by the vehicle dynamics module; a double-sided linear actuator is used to simulate the rear-wheel steering rod load of an actual vehicle through force control, which more accurately reflects the actual vehicle working conditions; in addition, the present invention designs a series of test cases, which comprehensively evaluate the vehicle performance indicators that need to be evaluated for active rear-wheel steering, such as turning radius, sideslip angle of the center of mass, and yaw angular velocity, in multiple dimensions. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0039] Figure 1 Schematic diagram of the rear-wheel steering multi-physics-in-the-loop test bench. DETAILED DESCRIPTION

[0040] The present invention will be further described below in conjunction with embodiment:

[0041] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0042] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings. At the same time, in the description of the present invention, the terms "first", "second", etc. are used only to distinguish the description and should not be understood as indicating or implying relative importance.

[0043] The bench test of the active rear wheel steering device of the present invention is carried out based on the rear wheel steering multi-physics-in-the-loop test bench. Figure 1 As shown in the figure, the rear-wheel steering multi-physics-in-the-loop test bench includes: ARS sample, left linear actuator, right linear actuator, test bench controller, fixture and fixture.

[0044] The test bench controller uses a HIL simulator and is the central control center of the entire test bench. The ARS test control program is downloaded to the test bench controller, including the driver operation and vehicle dynamics module, the test bench control module and the performance evaluation module.

[0045] The ARS sample is fixed on a fixture and a fixture.

[0046] The left and right linear actuators are respectively connected to the left and right pull rod fork arms of the ARS sample. The left and right linear actuators are integrated with force sensors and displacement sensors. The push rods of the left and right linear actuators can only perform linear reciprocating motion along the axis of the actuator.

[0047] The driver control and vehicle dynamics module sends the gear position, vehicle speed, steering wheel angle, steering wheel speed, longitudinal acceleration, lateral acceleration, and yaw rate signals to the CAN for use by the ARS sample; the driver control and vehicle dynamics module also sends the left rear steering rod force and the right rear steering rod force to the test bench control module.

[0048] After signal conditioning such as filtering and direction conversion calculations, the test bench control module converts the left and right rear steering rod forces into target values ​​for the load forces of the left and right linear actuator cylinders and sends them to the left and right linear actuator cylinders, controlling the push rods of the left and right linear actuator cylinders to perform linear motion in a force-controlled manner.

[0049] The left and right linear actuators send actual values ​​of the load forces of the left and right linear actuators to the test bench control module.

[0050] The ARS prototype utilizes the input of the above signals to control the rack stroke and thus the rear wheel steering angle, so that the sideslip angle of the center of mass is as close as possible to the target value of 0; the ARS prototype rack pushes the push rods of the left and right linear actuators to perform linear motion, and the strokes of the left and right linear actuators are collected, which are converted by the test bench control module into the displacements of the left and right rear steering rods and sent to the driver operation and vehicle dynamics modules, thereby realizing a closed-loop test.

[0051] The driver control and vehicle dynamics module sends signals such as the sideslip angle, front wheel turning angle, and rear wheel turning angle to the performance evaluation module, and the ARS sample sends signals such as the ARS working status, working current, and rack position to the performance evaluation module for performance evaluation.

[0052] Before starting the following test process, the present invention needs to ensure that the ARS working state is a normal working state without error, the working current is the ARS static working current, and the rack position is the initial position.

[0053] The bench test of the active rear wheel steering device of the present invention consists of three parts: a low-speed steering flexibility test, a steering wheel angle step test, and a steering wheel angle periodic change sensitivity stability test.

[0054] 1. Low-speed steering flexibility test:

[0055] 1. Set the power supply pressure, vehicle speed control mode, and path of the ARS prototype. Increase the steering wheel angle to its maximum positive value at a certain steering wheel angle change rate. After the vehicle travels a circle at a constant speed, calculate the vehicle's turning radius R1.

[0056] 2. While keeping other conditions unchanged, reset the power supply pressure of the ARS sample and calculate the turning radius R2 of the vehicle;

[0057] 3. Calculate the vehicle's turning radius optimization rate ΔR1:

[0058] ΔR1=(R1-R2) / R2.

[0059] 4. Maintaining constant voltage and vehicle speed, increase the steering wheel angle to its maximum positive value at a certain steering wheel angle change rate. Collect the front and rear wheel angle values ​​during the period. At the same time, map the front and rear wheel angle values ​​one by one to form a front-wheel angle-rear wheel angle curve, and calculate the proportional correspondence between the front and rear wheel angles.

[0060] 5. If ΔR1>2, the turning radius reduction capability of ARS is significantly improved compared to that of front-wheel steering only, but not vice versa.

[0061] 2. Steering wheel angle step test:

[0062] 1. Set the power supply pressure, vehicle speed control mode, and path of the ARS prototype. Gradually increase the vehicle's steering wheel angle until the vehicle's lateral acceleration reaches a certain value. Maintain the current steering wheel angle unchanged. After the vehicle travels a circle at a constant speed, increase the steering wheel angle at a certain steering wheel angle change rate. Calculate the vehicle's maximum sideslip angle β1 during this period.

[0063] When the steering wheel angle increases to a certain value, the current time is set to t1. When the vehicle's yaw rate reaches 90% of its steady-state value γ1 for the first time, the current time is set to t2. The vehicle's yaw rate reaction time t3 during the calculation period is calculated:

[0064] t3 = t2 - t1

[0065] The maximum value of the vehicle's yaw rate γ2 during the acquisition period and the vehicle's yaw rate overshoot γ3 during the calculation period are:

[0066] γ3=(γ2-γ1) / γ1.

[0067] 2. With other conditions unchanged, reset the power supply pressure of the ARS sample and calculate the vehicle's maximum center of mass sideslip angle β2, vehicle yaw rate response time t4, and vehicle yaw rate overshoot γ4 during the calculation period.

[0068] 3. Calculate the maximum fluctuation of the center of mass sideslip angle Δβ1 when ARS is activated, Δβ1=β2, calculate the yaw rate followability Δt1 when ARS is activated, Δt1=t4, and the yaw rate follow optimization rate Δt2, Δt2=(t3-t4) / t3, calculate the yaw rate overshoot Δγ1 when ARS is activated, Δγ1=γ4, and the yaw rate overshoot optimization rate Δγ2, Δγ2=γ3-γ4.

[0069] 4. If Δβ1<0.2deg, Δt1<0.1s, and Δγ1<10%, the ARS's high-speed center-of-mass sideslip angle suppression capability and yaw rate following capability meet the requirements; otherwise, they do not meet the requirements.

[0070] If Δt2>50% and Δγ2>30%, the center of mass sideslip angle suppression capability and yaw rate following capability of ARS are significantly improved compared with front-wheel steering only.

[0071] 3. Steering wheel angle periodic change sensitivity stability test:

[0072] 1. Set the power supply pressure, speed control mode and path of the ARS sample.

[0073] Starting at 0, the vehicle's steering wheel angle is controlled according to a sinusoidal curve, with 10 cycles of the curve. At the same time, the slip angle is mapped to the steering wheel angle, forming a slip angle (ordinate)-steering wheel angle (abscissa) curve. The yaw rate is also mapped to the steering wheel angle, forming a yaw rate (ordinate)-steering wheel angle (abscissa) curve.

[0074] 2. Within one sinusoidal period of the steering wheel angle, take the sideslip angle and yaw rate values ​​within four steering wheel angle ranges: the amplitude of the steering wheel angle in the positive direction is 20% to 80% of the amplitude in the positive direction, the amplitude of the steering wheel angle in the positive direction is 80% to 20% of the amplitude in the positive direction, the amplitude of the steering wheel angle in the negative direction is 20% to 80% of the amplitude in the negative direction, and the amplitude of the steering wheel angle in the negative direction is 80% to 20% of the amplitude in the negative direction.

[0075] By fitting the least squares method, the slope K of the center of mass slip angle relative to the steering wheel angle within the above four steering wheel angle ranges is calculated. βi1 , K βi2 , K βi3 , K βi4 The average value of the four is the center of mass side slip angle sensitivity M within a steering wheel angle sinusoidal cycle. βi (i=1,2,…,10).

[0076] The slope of the yaw rate relative to the steering wheel angle K γi1 , K γi2 , K γi3 , K γi4 The average value of the four is the yaw rate sensitivity M within a steering wheel angle sinusoidal cycle. γi (i=1,2,…,10).

[0077] The variance of the center of mass sideslip angle sensitivity calculated for 10 cycles is the center of mass sideslip angle sensitivity stability ΔM β The variance of the yaw rate sensitivity over 10 cycles is the yaw rate sensitivity stability ΔM γ :

[0078]

[0079]

[0080]

[0081]

[0082] 3. If ΔM β <0.05 and ΔM γ<2, the center of mass sideslip angle sensitivity stability and yaw rate sensitivity stability of ARS meet the requirements, otherwise they do not meet the requirements.

[0083] Example 1

[0084] Low-speed steering flexibility test

[0085] 1. Set the ARS prototype's power supply voltage to 0V, the vehicle speed control mode to low-speed constant speed control at 5km / h, and the path to a 100m*100m square with a road adhesion coefficient of 1.0. Increase the steering wheel angle to its maximum positive value at a steering wheel angle change rate of 180deg / s. After the vehicle completes one circle at a constant speed, calculate the vehicle's turning radius, R1.

[0086] 2. Set the power supply voltage of the ARS sample to 12V, and keep other conditions the same as when the power supply voltage is set to 0V. Calculate the turning radius R2 of the vehicle.

[0087] 3. Calculate the vehicle's turning radius optimization rate ΔR1:

[0088] ΔR1=(R1-R2) / R2.

[0089] 4. Maintaining constant voltage and vehicle speed, increase the steering wheel angle to its maximum positive value at a steering wheel angle change rate of 10 degrees per second. Collect the front and rear wheel angles during this period. At the same time, map the front and rear wheel angles one-to-one to form a front-wheel angle-rear wheel angle curve. Calculate the proportional relationship between the front and rear wheel angles.

[0090] 5. If ΔR1>2, the turning radius reduction capability of ARS is significantly improved compared to that of front-wheel steering only, but not vice versa.

[0091] Example 2

[0092] Steering wheel angle step test

[0093] 1. Set the ARS sample's power supply voltage to 0V, the vehicle speed control mode to high-speed constant speed control, the speed to 80km / h, the path to a road adhesion coefficient of 1.0 and a 100m*100m square road surface, and gradually increase the vehicle steering angle from 0 until the vehicle's lateral acceleration reaches 3m / s 2Keep the current steering wheel angle unchanged, make the vehicle travel a circle at a constant speed, then increase the steering wheel angle to 90 degrees at a steering wheel angle change rate of 180 degrees / s and maintain it for 10 seconds. Calculate the vehicle's maximum sideslip angle β1 during this period. During this period, when the steering wheel angle increases to 45 degrees, set the current time to t1. When the vehicle's yaw rate reaches 90% of its steady-state value γ1 for the first time, set the current time to t2. Calculate the vehicle's yaw rate reaction time t3 during this period:

[0094] t3 = t2 - t1

[0095] The maximum value of the vehicle's yaw rate γ2 during the acquisition period and the vehicle's yaw rate overshoot γ3 during the calculation period are:

[0096] γ3=(γ2-γ1) / γ1

[0097] 2. Set the power supply voltage of the ARS sample to 12V, and keep other parameters the same as when the power supply voltage is set to 0V. Calculate the vehicle's maximum center of mass sideslip angle β2, vehicle yaw rate response time t4, and vehicle yaw rate overshoot γ4 during the calculation period.

[0098] 3. Calculate the maximum fluctuation of the center of mass sideslip angle Δβ1 when ARS is activated, Δβ1=β2, calculate the yaw rate followability Δt1 when ARS is activated, Δt1=t4, and the yaw rate follow optimization rate Δt2, Δt2=(t3-t4) / t3, calculate the yaw rate overshoot Δγ1 when ARS is activated, Δγ1=γ4, and the yaw rate overshoot optimization rate Δγ2, Δγ2=γ3-γ4.

[0099] 4. If Δβ1 < 0.2 degrees, Δt1 < 0.1 seconds, and Δγ1 < 10%, the ARS's high-speed slip angle suppression and yaw rate tracking capabilities meet the requirements; otherwise, they do not meet the requirements. If Δt2 > 50% and Δγ2 > 30%, the ARS's slip angle suppression and yaw rate tracking capabilities are significantly improved compared to front-wheel steering only.

[0100] Example 3

[0101] Steering wheel angle periodic change sensitivity stability test

[0102] 1. Set the ARS prototype's power supply voltage to 12V, the vehicle speed control mode to high-speed constant speed control, the speed to 80km / h, and the path to a 10km straight road with a road adhesion coefficient of 1.0. Control the vehicle's steering wheel angle according to a sinusoidal curve with a starting value of 0. The sinusoidal curve has a period of 5s and an amplitude value such that the vehicle's maximum lateral acceleration reaches 1m / s. 2The amplitude of the steering wheel angle is 10 cycles of the sine curve. During this period, at the same time, the center of mass sideslip angle and the steering wheel angle are mapped one by one to form the center of mass sideslip angle (ordinate)-steering wheel angle (abscissa) curve. The yaw rate and the steering wheel angle are mapped one by one to form the yaw rate (ordinate)-steering wheel angle (abscissa) curve.

[0103] 2. Within a sinusoidal period of the steering wheel angle, take the values ​​of the center of mass slip angle and yaw rate within four steering wheel angle ranges: the amplitude of the steering wheel angle in the positive direction is 20% to the amplitude of the positive direction is 80%, the amplitude of the positive direction is 80% to the amplitude of the positive direction is 20%, the amplitude of the negative direction is 20% to the amplitude of the negative direction is 80%, and the amplitude of the negative direction is 80% to the amplitude of the negative direction is 20%. Calculate the slope K of the center of mass slip angle relative to the steering wheel angle within the above four steering wheel angle ranges by fitting the least squares method. βi1 , K βi2 , K βi3 , K βi4 The average value of the four is the center of mass side slip angle sensitivity M within a steering wheel angle sinusoidal cycle. βi (i=1,2,…,10) The slope K of the yaw rate relative to the steering wheel angle γi1 , K γi2 , K γi3 , K γi4 The average value of the four is the yaw rate sensitivity M within a steering wheel angle sinusoidal cycle. γi (i=1,2,…,10). The variance of the center of mass sideslip angle sensitivity calculated over 10 cycles is the center of mass sideslip angle sensitivity stability ΔM. β The variance of the yaw rate sensitivity over 10 cycles is the yaw rate sensitivity stability ΔM γ :

[0104]

[0105]

[0106]

[0107]

[0108] 3. If ΔM β <0.05 and ΔM γ <2, the center of mass sideslip angle sensitivity stability and yaw rate sensitivity stability of ARS meet the requirements, otherwise they do not meet the requirements.

[0109] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A bench test method for an active rear wheel steering device, characterized in that: The following steps are involved: A. Low-speed steering flexibility test A1. Set the power supply pressure, vehicle speed, and path of the ARS prototype. Increase the steering wheel angle to the maximum positive value. After the vehicle drives a circle at a constant speed, calculate the vehicle's turning radius R1. A2. Adjust the power supply pressure of the ARS sample and calculate the vehicle's turning radius R2; A3. Calculate the vehicle's turning radius optimization rate ΔR1, where ΔR1 = (R1 - R2) / R2; A4. Maintaining the voltage and vehicle speed constant, increase the steering wheel angle to its maximum positive value. Collect the front and rear wheel angles to form a front-wheel angle-rear wheel angle curve, and calculate the proportional relationship between the front and rear wheel angles. A5. If ΔR1>2, the turning radius reduction capability of ARS is significantly improved compared to front-wheel steering only, but not otherwise; B. Steering wheel angle step test B1. Set the ARS prototype's power supply pressure, vehicle speed, and path. Gradually increase the vehicle's steering wheel angle until the vehicle's lateral acceleration reaches a certain value. Maintain the current steering wheel angle. After the vehicle travels a circle at a constant speed, increase the steering wheel angle and calculate the vehicle's maximum sideslip angle β1. When the steering wheel angle increases to a specific value, the current time is set to t1. When the vehicle yaw rate reaches 90% of its steady-state value γ1 for the first time, the current time is set to t2. The vehicle yaw rate reaction time t3 is calculated, t3 = t2 - t1. The maximum yaw rate of the vehicle during the acquisition period γ2 is used to calculate the vehicle yaw rate overshoot γ3, γ3 = (γ2-γ1) / γ1; B2. Adjust the power supply pressure of the ARS sample and calculate the vehicle's maximum center of mass sideslip angle β2, vehicle yaw rate response time t4, and vehicle yaw rate overshoot γ4 during the calculation period. B3. Calculate the maximum fluctuation of the center of mass sideslip angle Δβ1 when the ARS is activated, where Δβ1 = β2. Calculate the yaw rate followability Δt1 when the ARS is activated, where Δt1 = t4, and the yaw rate followability optimization rate Δt2 when the ARS is activated, where Δt2 = (t3 - t4) / t3. Calculate the yaw rate overshoot Δγ1 when the ARS is activated, where Δγ1 = γ4, and the yaw rate overshoot optimization rate Δγ2, where Δγ2 = γ3 - γ4. B4. Determine whether the ARS's high-speed sideslip angle suppression capability and yaw rate tracking capability meet the requirements and whether the ARS's sideslip angle suppression capability and yaw rate tracking capability have improved; C. Steering wheel angle periodic change sensitivity stability test C1. Set the power supply pressure, vehicle speed control mode, and path of the ARS prototype. Control the vehicle steering wheel angle according to a sinusoidal curve. The steering wheel angle is subjected to a 10-cycle sinusoidal curve to form a center of mass sideslip angle-steering wheel angle curve and a yaw rate-steering wheel angle curve. C2. Within a steering wheel angle sinusoidal cycle, take the center of mass slip angle and yaw rate values ​​within the four steering wheel angle ranges; calculate the center of mass slip angle sensitivity M through least squares fitting. βi (i=1,2,…,10) and yaw rate sensitivity M γi (i=1,2,…,10); Calculate the center of mass side slip angle sensitivity stability ΔM β and yaw rate sensitivity stability ΔM γ : The four steering wheel angle ranges are: the amplitude of the steering wheel angle in the positive direction of 20% to the amplitude of the positive direction of 80%, the amplitude of the steering wheel angle in the positive direction of 80% to the amplitude of the positive direction of 20%, the amplitude of the steering wheel angle in the negative direction of 20% to the amplitude of the negative direction of 80%, and the amplitude of the steering wheel angle in the negative direction of 80% to the amplitude of the steering wheel angle in the negative direction of 20%; The slope K of the sideslip angle relative to the steering wheel angle βi1 , K βi2 , K βi3 , K βi4 The average value of the four is the center of mass side slip angle sensitivity M within a steering wheel angle sinusoidal cycle. βi (i=1,2,…,10); slope K of yaw rate relative to steering wheel angle γi1 , K γi2 , K βi3 , K βi4 The average value of the four is the yaw rate sensitivity M within a steering wheel angle sinusoidal cycle. βi (i=1,2,…,10); C3. Determine whether the center of mass sideslip angle sensitivity stability and yaw rate sensitivity stability of the ARS meet the requirements.

2. The bench test method for an active rear wheel steering device according to claim 1, characterized in that: In step A1, the power supply pressure of the ARS sample is 0V, the vehicle speed is 5km / h, the path is a 100m*100m square road with a road adhesion coefficient of 1.0, and the steering wheel angle is increased to the positive maximum value at a steering wheel angle change rate of 180deg / s.

3. The bench test method for an active rear wheel steering device according to claim 1, characterized in that: In step A4, the steering wheel angle is increased to a positive maximum value at a steering wheel angle change rate of 10 degrees per second. At the same time, the front wheel angle and the rear wheel angle are mapped one to one to form a front wheel angle-rear wheel angle curve.

4. The bench test method for an active rear wheel steering device according to claim 1, characterized in that: Step B1: The power supply voltage of the ARS sample is 0V, the vehicle speed is 80km / h, the path is a 100m*100m square road with a road adhesion coefficient of 1.0, and the vehicle lateral acceleration reaches 3m / s 2 When the current steering wheel angle is kept unchanged, the steering wheel angle is increased to 90 degrees at a steering wheel angle change rate of 180 degrees per second and maintained for 10 seconds. At time t1, the steering wheel angle is 45 degrees.

5. The bench test method for an active rear wheel steering device according to claim 1, characterized in that: Step B4, specifically: if Δβ1<0.2deg and Δt1<0.1s and Δγ1<10%, then the high-speed center of mass sideslip angle suppression capability and yaw rate following capability of the ARS meet the requirements; otherwise, the requirements are not met; If Δt2>50% and Δβ2>30%, the center of mass sideslip angle suppression capability and yaw rate following capability of ARS are significantly improved compared with only front-wheel steering.

6. The bench test method for an active rear wheel steering device according to claim 1, characterized in that: Step C1: The power supply voltage of the ARS sample is 12V. The vehicle speed is 80km / h, the path is a straight road with a road adhesion coefficient of 1.0 and a length of 10km. The period of the sine curve is 5s, and the amplitude value is the maximum lateral acceleration of the vehicle reaches 1m / s. 2 At the same moment, the center of mass sideslip angle and the steering wheel angle are mapped one by one to form a center of mass sideslip angle-steering wheel angle curve, and the yaw rate and the steering wheel angle are mapped one by one to form a yaw rate-steering wheel angle curve.

7. The bench test method for an active rear wheel steering device according to claim 1, characterized in that: Step C3, specifically: if ΔM β <0.05 and ΔM γ <2, the center of mass sideslip angle sensitivity stability and yaw rate sensitivity stability of ARS meet the requirements, otherwise they do not meet the requirements.

8. A bench test device for an active rear wheel steering system, characterized by: It includes an ARS sample, a left linear actuator, a right linear actuator, a test bench controller, and a fixing fixture and fixing device for the ARS sample; wherein, the test bench controller adopts a HIL simulator, including a driver operation and vehicle dynamics module, a test bench control module and a performance evaluation module; the left and right linear actuators are respectively connected to the left and right pull rod fork arms of the ARS sample, and the left and right linear actuators are integrated with force sensors and displacement sensors. The push rods of the left and right linear actuators can only perform linear reciprocating motion along the axis of the actuator.

9. The bench test device for an active rear wheel steering device according to claim 8, characterized in that: The driver control and vehicle dynamics module sends the gear position, vehicle speed, steering wheel angle, steering wheel speed, longitudinal acceleration, lateral acceleration, and yaw rate signals to the CAN, and sends the left rear steering rod force and the right rear steering rod force to the test bench control module; After signal conditioning and direction conversion, the test bench control module converts the left and right rear steering rod forces into target values ​​for the left and right linear actuators and sends them to the left and right linear actuators, thereby controlling the push rods of the left and right linear actuators to perform linear motion. The left and right linear actuators send the actual values ​​of the left and right linear actuator load forces to the test bench control module. The ARS prototype controls the rear wheel steering angle by controlling the rack travel, so that the center of mass slip angle is as close as possible to the target value of 0; the ARS prototype rack pushes the push rods of the left and right linear actuators to perform linear motion, and the left and right linear actuator strokes are collected. The test bench control module converts them into the displacement of the left and right rear steering rods and sends them to the driver control and vehicle dynamics modules to achieve a closed-loop test; The driver control and vehicle dynamics module sends the center of mass sideslip angle, front wheel steering angle, and rear wheel steering angle signals to the performance evaluation module, and the ARS sample sends the ARS working status, working current, and rack position signals to the performance evaluation module for performance evaluation.

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