Automobile power-assisted steering test system and method

Abstract

The embodiment of the invention discloses an automobile power-assisted steering test system and method, and relates to the technical field of automobile electronics. An EPS controller in the automobile power-assisted steering test system is used for acquiring an input torque generated by a driver simulation motor through an angle torque sensor; according to the input torque and the state information of the vehicle, the power-assisted torque needing to be output by the EPS motor in the steering process is determined; the power-assisted torque is sent to an EPS motor, so that the EPS motor assists the vehicle in steering; if the input torque, the power-assisted torque and the actual resistance torque of the rocker arm end are balanced in the steering process of the vehicle, and the amplitude and the variation trend of the power-assisted torque all accord with the preset power-assisted characteristic curve, the vehicle power-assisted steering test passes. Therefore, by introducing a driver steering wheel input part and a steering resistance simulation part, the automobile power-assisted steering test system can simulate the working principle of a steering system more truly, so that the test precision and effect are improved.

Description

Technical Field

[0001] This application relates to the field of automotive electronics technology, and in particular to a power steering testing system and method for automobiles. Background Art

[0002] The steering system is a key component of commercial vehicles, and its performance directly affects the vehicle's handling, safety, and driving comfort. Due to the high center of gravity, large front axle mass, and high steering resistance of commercial vehicles, traditional hydraulic power steering (HPS) systems have long dominated due to their reliability and stability. However, with the development trends of intelligent and electric vehicles, electro-hydraulic hybrid steering systems integrating electric power steering (EPS) and HPS are gradually becoming the mainstream solution, combining the reliability of HPS with the flexibility of EPS.

[0003] Currently, such as Figure 1 As shown, the steering test system typically uses a coaxial design of servo motor 11 and EPS motor 13 to drive each other, and uses an inter-axle torque sensor 12 to detect the assist torque output by EPS motor 13.

[0004] However, while the design of the aforementioned steering test system has improved the scalability of testing different EPS types to some extent, it cannot directly simulate the road resistance encountered by commercial vehicles during actual steering. At the same time, it lacks subjective evaluation of steering feel to some extent, thus affecting the test accuracy and effectiveness of steering tests. Summary of the Invention

[0005] To address the aforementioned issues, this application provides a power steering testing system and method for automobiles, which can not only more accurately simulate steering behavior under real driving conditions, but also effectively improve the testing accuracy and effectiveness of steering tests.

[0006] The embodiments of this application disclose the following technical solutions:

[0007] In a first aspect, this application discloses an automotive power steering testing system, the system comprising: a driver simulation motor, a steering angle torque sensor, a resistance torque simulation motor, an electric power steering EPS controller, and an EPS motor;

[0008] The EPS controller is used to obtain the input torque generated by the driver simulation motor through the steering torque sensor;

[0009] The EPS controller is also used to determine, based on the input torque and the vehicle's status information, the assist torque that the EPS motor needs to output during the vehicle's steering process.

[0010] The EPS controller is also configured to send the assist torque to the EPS motor so that the EPS motor assists the vehicle in steering according to the assist torque;

[0011] The EPS controller is further configured to indicate that the power steering test of the vehicle passes if, during the steering process of the vehicle, the input torque, the assist torque, and the actual resistance torque at the rocker arm end are in torque balance, and the amplitude and trend of the assist torque conform to the preset assist characteristic curve. The actual resistance torque at the rocker arm end is the product of the steering gear reduction ratio and the equivalent column end resistance torque, and the equivalent column end resistance torque is determined by the resistance torque simulation motor.

[0012] Optionally, the torque balance formula between the input torque, the assist torque, and the actual resistance torque at the rocker arm end is as follows:

[0013]

[0014] in, The steering gear reduction ratio, For input torque, To assist torque, This refers to the reduction ratio of the EPS. This represents the actual resistance torque at the rocker arm end.

[0015] Optionally, the formula for determining the actual resistance torque at the rocker arm end is as follows:

[0016] =

[0017] in, This represents the actual resistance torque at the rocker arm end. The steering resistance torque at the rocker arm end, This is the hydraulic assist torque at the rocker arm end.

[0018] Optionally, the equivalent end resistance torque of the tubing is determined as follows:

[0019] The steering torque sensor is used to acquire the input torque generated by the driver simulation motor and the steering wheel angle information;

[0020] The steering angle torque sensor is also used to input the steering angle information into the vehicle dynamics model to obtain the steering resistance torque at the rocker arm end;

[0021] The angle torque sensor is also used to input the input torque into the hydraulic power assist model to obtain the hydraulic power assist torque at the rocker arm end;

[0022] The resistance torque simulation motor is used to determine the equivalent column end resistance torque by dividing the difference between the steering resistance torque at the rocker arm end and the hydraulic assist torque at the rocker arm end by the steering gear reduction ratio.

[0023] Optionally, the hydraulic assist torque at the rocker arm end is determined by the following formula:

[0024] ;

[0025] in, For the hydraulic assist torque at the rocker arm end, r GS The pitch circle radius of the steering gear sector. For hydraulic power assistance, A P P is the piston area of ​​the hydraulic cylinder. In P is the pressure of the liquid flowing out of the hydraulic cylinder and into the rotary valve. Out The pressure of the liquid flowing out of the rotary valve and into the hydraulic cylinder.

[0026] Optionally, the flow characteristics of the rotary valve satisfy the following formula:

[0027] ;

[0028] Among them, Q i Q represents the flow rate at each port of the rotary valve. P Q is the flow rate of the liquid exiting the hydraulic pump. Out Q is the flow rate of the fluid flowing from the rotary valve into the hydraulic cylinder. In C is the flow rate of the fluid exiting the hydraulic cylinder and entering the rotary valve. Q Let A be the flow coefficient. i ΔP represents the throttling area of ​​each valve port of the rotary valve. i ρ represents the pressure difference across each valve port of the rotary valve, and ρ represents the hydraulic oil density.

[0029] Secondly, this application discloses a method for testing automotive power steering, applied to the electric power steering (EPS) controller of the automotive power steering testing system as described in the first aspect, the method comprising:

[0030] The input torque generated by the driver's simulated motor is obtained through the steering torque sensor;

[0031] Based on the input torque and the vehicle's status information, determine the assist torque that the EPS motor needs to output during the vehicle's steering process;

[0032] The assist torque is sent to the EPS motor so that the EPS motor assists the vehicle in steering according to the assist torque;

[0033] If, during the steering process of the vehicle, the input torque, the assist torque, and the actual resistance torque at the rocker arm end are in torque balance, and the amplitude and trend of the assist torque conform to the preset assist characteristic curve, then the power steering test of the vehicle is deemed to have passed. The actual resistance torque at the rocker arm end is the product of the steering gear reduction ratio and the equivalent column end resistance torque, which is determined by the resistance torque simulation motor.

[0034] Optionally, the torque balance formula between the input torque, the assist torque, and the actual resistance torque at the rocker arm end is as follows:

[0035]

[0036] in, The steering gear reduction ratio, For input torque, To assist torque, This refers to the reduction ratio of the EPS. This represents the actual resistance torque at the rocker arm end.

[0037] Optionally, the formula for determining the actual resistance torque at the rocker arm end is as follows:

[0038] =

[0039] in, This represents the actual resistance torque at the rocker arm end. The steering resistance torque at the rocker arm end, This is the hydraulic assist torque at the rocker arm end.

[0040] Optionally, the equivalent end resistance torque of the tubing is determined as follows:

[0041] The steering torque sensor acquires the input torque generated by the driver simulation motor and the steering wheel angle information;

[0042] The steering angle torque sensor inputs the steering angle information into the vehicle dynamics model to obtain the steering resistance torque at the rocker arm end;

[0043] The angle torque sensor inputs the input torque into the hydraulic power assist model to obtain the hydraulic power assist torque at the rocker arm end.

[0044] The resistance torque simulation motor determines the equivalent column end resistance torque by dividing the difference between the steering resistance torque at the rocker arm end and the hydraulic assist torque at the rocker arm end by the steering gear reduction ratio.

[0045] Optionally, the hydraulic assist torque at the rocker arm end is determined by the following formula:

[0046] ;

[0047] in, For the hydraulic assist torque at the rocker arm end, r GS The pitch circle radius of the steering gear sector. For hydraulic power assistance, A P P is the piston area of ​​the hydraulic cylinder. In P is the pressure of the liquid flowing out of the hydraulic cylinder and into the rotary valve. Out The pressure of the liquid flowing out of the rotary valve and into the hydraulic cylinder.

[0048] Optionally, the flow characteristics of the rotary valve satisfy the following formula:

[0049] ;

[0050] Among them, Q i Q represents the flow rate at each port of the rotary valve. P Q is the flow rate of the liquid exiting the hydraulic pump. Out Q is the flow rate of the fluid flowing from the rotary valve into the hydraulic cylinder. In C is the flow rate of the fluid exiting the hydraulic cylinder and entering the rotary valve. Q Let A be the flow coefficient. i ΔP represents the throttling area of ​​each valve port of the rotary valve. i ρ represents the pressure difference across each valve port of the rotary valve, and ρ represents the hydraulic oil density.

[0051] Compared with the prior art, this application has the following beneficial effects:

[0052] This application discloses an automotive power steering testing system and method. The disclosed system incorporates driver steering wheel input and a steering resistance simulation component, enabling a more realistic simulation of the steering system's working principle, thereby improving testing accuracy and effectiveness. Based on this system, the EPS controller can control the EPS motor to perform corresponding actions based on steering wheel torque, angle, and vehicle status information. Simultaneously with functional testing, it can also evaluate steering feel and performance, thus expanding and enriching the testing content to a certain extent. Attached Figure Description

[0053] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 This is a schematic diagram of a steering test system;

[0055] Figure 2 A schematic diagram of a first type of automotive power steering test system provided in an embodiment of this application;

[0056] Figure 3 A schematic diagram of a steering system structure of a real vehicle provided for an embodiment of this application;

[0057] Figure 4 A schematic diagram of a second type of automotive power steering testing system provided in an embodiment of this application;

[0058] Figure 5 A schematic diagram of a test bench provided in an embodiment of this application;

[0059] Figure 6 A schematic diagram of a third type of automotive power steering testing system provided in the embodiments of this application;

[0060] Figure 7 A schematic diagram of a fault test board provided in an embodiment of this application;

[0061] Figure 8 A schematic diagram of a hydraulic power assist model provided in an embodiment of this application;

[0062] Figure 9 A flowchart illustrating a vehicle power steering testing method provided in this application embodiment. DETAILED DESCRIPTION

[0063] See Figure 1 The diagram shows a schematic of a steering test system. Figure 1 As shown, the steering test system typically uses a coaxial design of servo motor 11 and EPS motor 13 to drive each other, and uses an inter-axle torque sensor 12 to detect the assist torque output by EPS motor 13.

[0064] However, while the design of the aforementioned steering test system has improved the scalability of testing different EPS types to some extent, it cannot directly simulate the road resistance encountered by commercial vehicles during actual steering. At the same time, it lacks subjective evaluation of steering feel to some extent, thus affecting the test accuracy and effectiveness of steering tests.

[0065] Through research, the inventors have proposed a power steering testing system and method for automobiles. The power steering testing system disclosed in this application introduces driver steering wheel input and a steering resistance simulation component, enabling the system to more realistically simulate the working principle of the steering system, thereby improving testing accuracy and effectiveness. Based on this power steering testing system, the EPS controller can control the EPS motor to perform corresponding actions based on steering wheel torque, angle, and vehicle status information. While conducting functional testing, it can also evaluate steering feel and performance, thus expanding and enriching the testing content to a certain extent.

[0066] In order to help those skilled in the art better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 those skilled in the art without creative work are within the scope of protection of this application.

[0067] See Figure 2 The figure is a schematic diagram of a first type of automotive power steering test system provided in an embodiment of this application. The automotive power steering test system 200 includes: a driver simulation motor 21, a steering angle torque sensor 22, a resistance torque simulation motor 23, an EPS controller 24, and an EPS motor 25.

[0068] EPS controller 24 is used to acquire the input torque generated by driver simulation motor 21 via angle torque sensor 22.

[0069] The steering torque sensor 22 is typically mounted on the steering column to detect input torque from two different sources: one is the input torque applied when the driver directly rotates the steering wheel, and the other is the input torque generated by the driver-simulated motor 21 in autonomous driving mode. The input torque reflects the driver's intention to change the vehicle's direction. For example, when the vehicle needs to perform a large steering maneuver, such as changing lanes on a highway or making sharp turns, the input torque will show a significant increasing trend; while when making minor adjustments to the direction while driving straight, it will exhibit small-amplitude, high-frequency torque fluctuations.

[0070] The EPS controller 24 is also used to determine the assist torque that the EPS motor 25 needs to output during the vehicle's steering process, based on the input torque and the vehicle's status information.

[0071] The vehicle's status information (obtained from the vehicle dynamics model) includes vehicle speed, steering angle, yaw rate / lateral acceleration, etc. This ensures that the EPS motor 25 can provide just the right amount of assistance, reducing the driver's workload while guaranteeing precise control during steering.

[0072] The EPS controller 24 is also used to send an assist torque request (indicating an assist torque) to the EPS motor 25 so that the EPS motor 25 assists in steering the vehicle according to the assist torque. Specifically, the assist torque is amplified by a reduction gear and then transmitted to the wheels via the steering column and steering gear, thereby providing active assistance in steering the vehicle.

[0073] It should be noted that the power assist torque output by the EPS motor 25 is not fixed, but dynamically adjusted according to the driving scenario. For example, in low-speed, high-steering conditions (such as parking or U-turns), the power assist torque can be increased to make the steering wheel lighter and reduce driver fatigue. In high-speed, fine-tuning conditions (such as lane keeping or high-speed lane changes), the power assist torque can be decreased to enhance the steering wheel's stability and improve driving stability. In emergency obstacle avoidance or rapid steering conditions, the power assist torque can dynamically increase with steering speed, thereby ensuring rapid response while avoiding oversteering. This application does not limit the specific driving scenarios.

[0074] The EPS controller 24 is also used to determine whether the power steering test of the vehicle passes if, during the vehicle's steering process, the input torque (applied by the driver or the analog motor 21), the assist torque (output by the EPS motor 25), and the actual resistance torque at the rocker arm end are balanced (i.e., the input torque + assist torque ≈ actual resistance torque at the rocker arm end) and the assist torque meets expectations (i.e., the amplitude and trend of the assist torque both conform to the preset assist characteristic curve). This indicates that the power steering function under the current test condition is normal. The actual resistance torque at the rocker arm end is the product of the steering gear reduction ratio and the equivalent column end resistance torque, which is determined by the resistance torque analog motor 23.

[0075] First, let's explain the structure of the steering system in the actual vehicle:

[0076] In terms of structure, the steering systems of actual vehicles can be divided into two main categories: separate and integrated. Separate systems offer better heat dissipation, with each component independently arranged, facilitating maintenance and replacement. However, they occupy more space and have a more complex layout, making it difficult to achieve a compact design, especially in vehicles with limited space. Integrated systems are compact and easy to arrange, making them suitable for space-constrained vehicle designs. However, integrated systems have poorer heat dissipation performance, require higher protection (such as waterproofing and dustproofing), and are more difficult to maintain.

[0077] In view of this, the steering system of the actual vehicle can adopt a column-type split electro-hydraulic composite steering system, which combines the advantages of electric power steering (EPS) and hydraulic power steering (HPS), ensuring heat dissipation performance and achieving flexible layout through split design.

[0078] See Figure 3 This figure is a schematic diagram of a steering system structure for a real vehicle according to an embodiment of this application. Figure 3 The steering system structure of the actual vehicle shown includes: steering wheel 31, steering angle torque sensor 32, column-type EPS 33, recirculating ball steering gear 34, hydraulic power steering cylinder 35, EPS controller 36, EPS motor 37, pump 38, and rotary valve 39.

[0079] The steering system of this vehicle operates as follows: First, the driver inputs a steering command by turning the steering wheel 31. Second, the steering angle and torque sensor 32 detects the steering angle information and input torque of the steering wheel 31 and transmits this information to the EPS controller 36. Third, the EPS controller 36 calculates the required amount and direction of power assist based on the received steering angle and input torque information. Fourth, the EPS controller 36 sends a control signal to the EPS motor 37, instructing it to generate the corresponding torque output. Fifth, the EPS motor 37 generates the required torque output according to the control signal and transmits it to the recirculating ball steering gear 32 through the column-type EPS 33. Sixth, the recirculating ball steering gear 32 converts the torque generated by the EPS motor 37 into mechanical motion, driving the steering mechanism to steer the wheels. Eighth, when needed, the hydraulic power assist cylinder 35 provides additional hydraulic power assist, and the pump 38 and rotary valve 39 work together to ensure a stable supply of hydraulic power assist.

[0080] It is understood that the steering test system disclosed in this application is a simplified version of the steering system of a real vehicle. Specifically, this application can use mathematical model simulation to replace some of the physical structure. The specific steps are as follows:

[0081] First, for the hydraulic power steering component, mathematical models are used to simulate the functions of components such as the pump, rotary valve, and hydraulic power steering cylinder. By establishing corresponding mathematical models, the need for actual hardware can be reduced, and the flexibility of testing can be improved. For example, fluid dynamics equations can be used to simulate the adjustment function of the rotary valve, and dynamic equations can be used to simulate the output force of the hydraulic power steering cylinder. Second, for the recirculating ball steering gear and its rear connection, the load on the recirculating ball steering gear and its rear connection is replaced as an equivalent whole with the torque load at the end of the steering column.

[0082] See Figure 4 This figure is a schematic diagram of a second type of automotive power steering testing system provided in an embodiment of this application. Figure 4As shown, the automotive power steering test system includes a first servo motor 41 (i.e., a driver simulation motor), a first torque sensor 42, a steering wheel 43, a steering angle torque sensor 44, a column-type EPS 45, a second torque sensor 46, and a second servo motor 47.

[0083] The system includes a first servo motor 41 to simulate driver input via the steering wheel. Controlling the rotation of the first servo motor simulates the driver's steering wheel movements. A first torque sensor 42, located below the first servo motor 41, measures the input torque applied by the first servo motor 41. The steering wheel 43 is operated by the driver. While in a real system it is typically manually operated by the driver, during automated testing, the rotation of the steering wheel is controlled by the first servo motor 41. A steering angle torque sensor 44, located below the steering wheel 43, detects the steering angle information and the actual input torque. A column-type EPS 45, located below the steering angle torque sensor 44, provides electric power assist. A second torque sensor 46 measures the resistance torque output by the second servo motor 47. The second servo motor 47 simulates the road resistance to the vehicle during steering. By controlling the output torque of the second servo motor 47, steering resistance under different road conditions can be simulated.

[0084] It is understandable that, such as Figure 4 As shown, the first servo motor 41 and the first torque sensor 42 are detachable and movable, used to switch between automatic testing and manual testing.

[0085] Therefore, through the above structural design, the torque balance formula between the input torque, the assist torque, and the actual resistance torque at the rocker arm end is as shown in the following formula (1):

[0086] (1)

[0087] in, The steering gear reduction ratio, For input torque, To assist torque, This refers to the reduction ratio of the EPS. The actual resistance torque at the rocker arm end is given by the formula shown in formula (2) below:

[0088] = (2)

[0089] in, This represents the actual resistance torque at the rocker arm end. The steering resistance torque at the rocker arm end, This is the hydraulic assist torque at the rocker arm end.

[0090] Next, combined Figure 5 Demonstrates how to apply a power steering testing system to a test bench:

[0091] See Figure 5 This figure is a schematic diagram of a test bench provided in an embodiment of this application. Figure 5 As shown, the test bench includes: a vehicle dynamics model animation display screen 51, a test spindle 52, a driver operation switch panel 53, an automatic testing device 54, a spindle support platform 55, a support platform adjustment device 56, a foot pedal 57, and a slide rail 58.

[0092] The vehicle dynamics model animation display screen 51 displays animations of the vehicle's dynamics model under different operating conditions, helping testers intuitively understand the system's working status. The test spindle 52, as the central component of the entire steering test system, connects the steering wheel and other related sensors, simulating steering operations during actual driving. The driver's control panel 53 provides a platform for testers to operate the system, including various switches and buttons. The driver's control panel 53 allows testers to manually operate the system, simulating car ignition and gear shifting, increasing flexibility and controllability. The automatic test equipment 54 integrates sensors and actuators to achieve automated testing functions, such as automatically applying and measuring torque. Therefore, the automatic test equipment 54 improves testing efficiency and accuracy, reduces human error, and is suitable for testing scenarios requiring repeatability and high precision. The spindle support platform 55 supports the test spindle, ensuring its stable operation. The support platform adjustment device 56 can adjust the height and angle of the support platform to adapt to different testing needs. The stable support platform adjustment device 56 ensures that the test spindle 52 will not experience unnecessary displacement or vibration during testing, thus affecting the accuracy of the test results. Foot pedal 57 is for testers to step on, simulating braking or acceleration. Foot pedal 57 allows testers to simulate real driving behaviors, such as braking and acceleration, thereby more realistically evaluating the performance of the steering test system under different driving conditions. Slide rail 58 is used to move the entire test bench, facilitating position adjustments and testing under different operating conditions.

[0093] See Figure 6 This figure is a schematic diagram of a third type of automotive power steering testing system provided in an embodiment of this application. Figure 6 As shown, dashed lines represent electrical signal transmission relationships, and solid lines represent mechanical connection relationships.

[0094] First, the EPS controller acquires the input torque generated by the driver simulation motor and the steering wheel angle information via the steering angle torque sensor. Second, the steering angle torque sensor inputs the angle information into the vehicle dynamics model to obtain the rocker arm end steering resistance torque. Subsequently, the steering angle torque sensor inputs the input torque into the hydraulic power assist model to obtain the rocker arm end hydraulic power assist torque. Finally, the resistance torque simulation motor determines the equivalent column end resistance torque by dividing the difference between the rocker arm end steering resistance torque and the rocker arm end hydraulic power assist torque by the steering gear reduction ratio.

[0095] It should be noted that the vehicle dynamics model used in this method is ModelBase, which contains multiple subsystem models and can comprehensively simulate various dynamic behaviors of the vehicle. It not only provides an output interface for steering resistance torque but also can calculate and update the state of its internal models in real time based on the vehicle's driving conditions. This application does not limit the specific vehicle dynamics model used.

[0096] It should also be noted that the hydraulic power steering model is used to simulate the characteristics of a hydraulic power steering system. By combining the rotary valve model and the cylinder block model, the hydraulic power steering torque at the rocker arm end is calculated. This data is used to further adjust the resistance torque to simulate the motor output, thereby ensuring a more realistic and accurate response of the steering test system.

[0097] It should also be noted that the angle torque sensor and the EPS controller can be connected via a hardwire, with a fault injection board inserted in series in the middle of the hardwire connection. See [link / reference] Figure 7 The figure is a schematic diagram of the principle of a fault injection board provided in an embodiment of this application. The function of the fault injection board is to control the closing or opening of each relay (including relay 1, relay 2, relay 3, and relay 4) through a software platform, thereby realizing the on / off function of the controller pin signals and simulating different fault conditions.

[0098] When the fault is not activated, the operating logic of each relay is as follows: the ECU output signal first completes the initial overcurrent protection through multiple fuse 1, then the relay 1 controls the on / off state, and then through multiple fuse 2, finally connects to the load; at the same time, the coil power supply circuit of relay 1 is controlled by relay 2, relay 3 and relay 4 in series, and the common terminal, ground terminal and battery voltage terminal of these three relays constitute the power supply logic; the circuit status can be fed back to the IO board through the signal for system monitoring or control.

[0099] When a fault is activated, relay 1 can control the on / off of the signal circuit from the angle torque sensor to the EPS controller, and relays 2, 3, and 4 can control the simulation of short circuits to the power supply / ground / other modules.

[0100] During testing, the fault injection board can be activated through the software platform to simulate various fault conditions. In one specific implementation, when the steering torque sensor cannot obtain the input torque and / or steering wheel angle information generated by rotating the vehicle's steering wheel (due to simulated sensor signal loss, sensor signal abnormality, etc.), the EPS motor cannot provide power assistance due to sensor failure.

[0101] See Figure 8 The figure is a schematic diagram of a hydraulic power assist model provided in an embodiment of this application. The hydraulic power assist model is used to simulate the characteristics of a hydraulic circuit, and the hydraulic assist torque at the rocker arm end is calculated by combining the rotary valve model and the cylinder model. Figure 8 In, Δδ S This indicates the relative angle of the steering torsion bar. Q1, Q2, Q3, and Q4 represent the flow rates at the four ports of the rotary valve, respectively. In Q Out and Q P These represent the fluid flow rates from the hydraulic cylinder into the rotary valve, from the rotary valve into the hydraulic cylinder, and from the hydraulic pump, respectively. P In 、P Out and P P These represent the fluid pressure flowing from the hydraulic cylinder into the rotary valve, the fluid pressure flowing from the rotary valve into the hydraulic cylinder, and the fluid pressure flowing out of the hydraulic pump, respectively. R This represents the liquid pressure in the storage tank. Specifically, the formula for the hydraulic cylinder is shown in equation (3):

[0102] (3)

[0103] Among them, F HPA and T HPA Indicates hydraulic power assist and hydraulic power assist torque, A P and r GS This represents the piston area of ​​the hydraulic cylinder and the pitch circle radius of the steering gear sector.

[0104] The formula for the rotary valve is shown in equation (4):

[0105] (4)

[0106] Among them, C Q and A i ΔP represents the flow coefficient and the throttling area of ​​each valve orifice. i ρ and ρ represent the pressure difference across each valve port and the hydraulic oil density, respectively. Using formulas (3) and (4), the characteristics of the hydraulic circuit can be simulated, and the hydraulic assist torque at the rocker arm end can be calculated. These formulas comprehensively consider the characteristics of the hydraulic cylinder and the rotary valve, ensuring the accuracy and reliability of the automotive power steering test system.

[0107] In summary, this application provides an automotive power steering testing system. By introducing driver steering wheel input and a steering resistance simulation component, the system can more realistically simulate the working principle of the steering system, thereby improving testing accuracy and effectiveness. Based on this system, the EPS controller can control the EPS motor to perform corresponding actions based on steering wheel torque, angle, and vehicle status information. While performing functional testing, it can also evaluate steering feel and performance, thus expanding and enriching the testing content to a certain extent.

[0108] See Figure 9 The figure is a flowchart of a vehicle power steering testing method provided in an embodiment of this application. The method, applied to an electric power steering (EPS) controller in a vehicle power steering testing system as described in the first aspect, includes:

[0109] S901: The input torque generated by the driver's simulated motor is obtained through the steering angle torque sensor;

[0110] S902: Based on the input torque and vehicle status information, determine the assist torque that the EPS motor needs to output during the vehicle's steering process;

[0111] S903: Sends assist torque to the EPS motor so that the EPS motor assists in vehicle steering according to the assist torque;

[0112] S904: If, during the vehicle's steering process, the input torque, the assist torque, and the actual resistance torque at the rocker arm end are in torque balance, and the amplitude and trend of the assist torque conform to the preset assist characteristic curve, then the vehicle's power steering test is passed. The actual resistance torque at the rocker arm end is the product of the steering gear reduction ratio and the equivalent column end resistance torque, which is determined by the resistance torque simulation motor.

[0113] In one specific implementation, the torque balance formula between the input torque, the assist torque, and the actual resistance torque at the rocker arm end is shown in the following formula (5):

[0114] (5)

[0115] in, The steering gear reduction ratio, For input torque, To assist torque, This refers to the reduction ratio of the EPS. This represents the actual resistance torque at the rocker arm end.

[0116] In one specific implementation, the formula for determining the actual resistance torque at the rocker arm end is shown in formula (6) below:

[0117] = (6)

[0118] in, This represents the actual resistance torque at the rocker arm end. The steering resistance torque at the rocker arm end, This is the hydraulic assist torque at the rocker arm end.

[0119] In one specific implementation, the equivalent end resistance torque of the tubing is determined as follows:

[0120] The steering torque sensor acquires the input torque generated by the driver's simulated motor and the steering wheel angle information;

[0121] The steering angle torque sensor inputs steering angle information into the vehicle dynamics model to obtain the steering resistance torque at the rocker arm end;

[0122] The angle torque sensor inputs the torque into the hydraulic power assist model to obtain the hydraulic power assist torque at the rocker arm end;

[0123] The resistance torque simulation motor determines the equivalent end resistance torque of the steering column by dividing the difference between the steering resistance torque at the rocker arm end and the hydraulic assist torque at the rocker arm end by the steering gear reduction ratio.

[0124] In one specific implementation, the hydraulic assist torque at the rocker arm end is determined by the following formula (7):

[0125] (7)

[0126] in, For the hydraulic assist torque at the rocker arm end, r GS The pitch circle radius of the steering gear sector. For hydraulic power assistance, A P P is the piston area of ​​the hydraulic cylinder. In P is the pressure of the liquid flowing out of the hydraulic cylinder and into the rotary valve. Out The pressure of the liquid flowing out of the rotary valve and into the hydraulic cylinder.

[0127] In one specific implementation, the flow characteristics of the rotary valve satisfy the following formula (8):

[0128] (8)

[0129] Among them, Q i Q represents the flow rate at each port of the rotary valve. P Q is the flow rate of the liquid exiting the hydraulic pump. Out Q is the flow rate of the fluid flowing from the rotary valve into the hydraulic cylinder. In C is the flow rate of the fluid exiting the hydraulic cylinder and entering the rotary valve. Q Let A be the flow coefficient. iΔP represents the throttling area of ​​each valve port of the rotary valve. i ρ represents the pressure difference across each valve port of the rotary valve, and ρ represents the hydraulic oil density.

[0130] In summary, this application provides a steering test method. By introducing driver steering wheel input and a steering resistance simulation component, the disclosed power steering test method can more realistically simulate the working principle of steering, thereby improving test accuracy and effectiveness. Based on this power steering test method, the EPS controller can control the EPS motor to perform corresponding actions based on steering wheel torque, angle, and vehicle status information. While performing functional tests, it can also evaluate steering feel and performance, thus expanding and enriching the test content to a certain extent.

[0131] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for the device and system embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiments. The device and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components indicated as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of the solution in this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0132] The above description is merely one specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A power steering testing system for automobiles, characterized in that, The system includes: a driver simulation motor, a steering angle torque sensor, a resistance torque simulation motor, an electric power steering (EPS) controller, and an EPS motor; The EPS controller is used to obtain the input torque generated by the driver simulation motor through the steering torque sensor; The EPS controller is also used to determine, based on the input torque and the vehicle's status information, the assist torque that the EPS motor needs to output during the vehicle's steering process. The EPS controller is also configured to send the assist torque to the EPS motor so that the EPS motor assists the vehicle in steering according to the assist torque; The EPS controller is further configured to indicate that the power steering test of the vehicle passes if, during the steering process of the vehicle, the input torque, the assist torque, and the actual resistance torque at the rocker arm end are in torque balance, and the amplitude and trend of the assist torque conform to the preset assist characteristic curve. The actual resistance torque at the rocker arm end is the product of the steering gear reduction ratio and the equivalent column end resistance torque, and the equivalent column end resistance torque is determined by the resistance torque simulation motor.

2. The system according to claim 1, characterized in that, The torque balance formula between the input torque, the assist torque, and the actual resistance torque at the rocker arm end is as follows: ； in, The steering gear reduction ratio, For input torque, To assist torque, This refers to the reduction ratio of the EPS. This represents the actual resistance torque at the rocker arm end.

3. The system according to claim 2, characterized in that, The formula for determining the actual resistance torque at the rocker arm end is as follows: = ； in, This represents the actual resistance torque at the rocker arm end. The steering resistance torque at the rocker arm end, This is the hydraulic assist torque at the rocker arm end.

4. The system according to claim 1, characterized in that, The equivalent end resistance torque of the tubing is determined as follows: The steering torque sensor is used to acquire the input torque generated by the driver simulation motor and the steering wheel angle information; The steering angle torque sensor is also used to input the steering angle information into the vehicle dynamics model to obtain the steering resistance torque at the rocker arm end; The angle torque sensor is also used to input the input torque into the hydraulic power assist model to obtain the hydraulic power assist torque at the rocker arm end; The resistance torque simulation motor is used to determine the equivalent column end resistance torque by dividing the difference between the steering resistance torque at the rocker arm end and the hydraulic assist torque at the rocker arm end by the steering gear reduction ratio.

5. The system according to claim 3 or 4, characterized in that, The hydraulic assist torque at the rocker arm end is determined by the following formula: ； in, For the hydraulic assist torque at the rocker arm end, r GS The pitch circle radius of the steering gear sector. For hydraulic power assistance, A P P is the piston area of ​​the hydraulic cylinder. In P is the pressure of the liquid flowing out of the hydraulic cylinder and into the rotary valve. Out The pressure of the liquid flowing out of the rotary valve and into the hydraulic cylinder.

6. The system according to claim 5, characterized in that, The flow characteristics of the rotary valve satisfy the following formula: ； Among them, Q i Q represents the flow rate at each port of the rotary valve. P Q is the flow rate of the liquid exiting the hydraulic pump. Out Q is the flow rate of the fluid flowing from the rotary valve into the hydraulic cylinder. In C is the flow rate of the fluid exiting the hydraulic cylinder and entering the rotary valve. Q Let A be the flow coefficient. i ΔP represents the throttling area of ​​each valve port of the rotary valve. i ρ represents the pressure difference across each valve port of the rotary valve, and ρ represents the hydraulic oil density.

7. A method for testing automotive power steering, characterized in that, The method, applied to an electric power steering (EPS) controller in an automotive power steering test system as described in any one of claims 1-6, comprises: The input torque generated by the driver's simulated motor is obtained through the steering torque sensor; Based on the input torque and the vehicle's status information, determine the assist torque that the EPS motor needs to output during the vehicle's steering process; The assist torque is sent to the EPS motor so that the EPS motor assists the vehicle in steering according to the assist torque; If, during the steering process of the vehicle, the input torque, the assist torque, and the actual resistance torque at the rocker arm end are in torque balance, and the amplitude and trend of the assist torque conform to the preset assist characteristic curve, then the power steering test of the vehicle is deemed to have passed. The actual resistance torque at the rocker arm end is the product of the steering gear reduction ratio and the equivalent column end resistance torque, which is determined by the resistance torque simulation motor.

8. The method according to claim 7, characterized in that, The torque balance formula between the input torque, the assist torque, and the actual resistance torque at the rocker arm end is as follows: ； in, The steering gear reduction ratio, For input torque, To assist torque, This refers to the reduction ratio of the EPS. This represents the actual resistance torque at the rocker arm end.

9. The method according to claim 8, characterized in that, The formula for determining the actual resistance torque at the rocker arm end is as follows: = ； in, This represents the actual resistance torque at the rocker arm end. The steering resistance torque at the rocker arm end, This is the hydraulic assist torque at the rocker arm end.

10. The method according to claim 7, characterized in that, The equivalent end resistance torque of the tubing is determined as follows: The steering torque sensor acquires the input torque generated by the driver simulation motor and the steering wheel angle information; The steering angle torque sensor inputs the steering angle information into the vehicle dynamics model to obtain the steering resistance torque at the rocker arm end; The angle torque sensor inputs the input torque into the hydraulic power assist model to obtain the hydraulic power assist torque at the rocker arm end. The resistance torque simulation motor determines the equivalent column end resistance torque by dividing the difference between the steering resistance torque at the rocker arm end and the hydraulic assist torque at the rocker arm end by the steering gear reduction ratio.

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