Simulation test method for electric power steering system

Abstract

The invention discloses a simulation test method for an electric power steering system, and relates to the field of automobile part tests, and the simulation test method comprises an HIL system, an electric power steering system performance test bench, a test bench control cabinet and a host. When the device is used, the HIL system sends a torque and angular velocity instruction simulating an attached operation direction of a vehicle steering wheel to the driving motor through a vehicle model and a preset driving condition, and sends a load force instruction simulating an attached direction of a vehicle load to the load motor at the same time; vehicle end node simulation signals such as the vehicle speed, the lateral acceleration and the engine working state position are sent to the electric power steering system assembly through CAN signals; the electric power steering system assembly is installed and fixed on the performance test bench according to a real vehicle arrangement angle, signals of real-time consumption current, power torque, angle, angular velocity, electric power steering system working state position and the like of the electric power steering system assembly are fed back to the HIL system, and closed-loop testing is achieved.

Description

Technical Field

[0001] The invention relates to the field of automobile parts testing, in particular to a simulation test method for an electric power steering system. Background Art

[0002] The electric power steering system is a power steering system that directly relies on the motor to provide auxiliary torque. Compared with the traditional hydraulic power steering system (HPS), the EPS system has many advantages. The traditional electric power steering system performance test applies a fixed load force and driving torque to the steering system to test the performance indicators of the steering system, focusing on the steering force and steering response speed under fixed conditions.

[0003] The current electric power steering system test cannot simulate the vehicle in the actual driving environment and test the performance and function of the steering system under the conditions of changing vehicle speed and load. Therefore, a simulation test method for an electric power steering system is urgently needed. Summary of the invention

[0004] The purpose of the present invention is to provide an electric power steering system simulation test method to solve the problem that the current electric power steering system test cannot simulate the actual driving environment of the vehicle and test the performance and function of the steering system under the conditions of vehicle speed and load changes.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a simulation test method for an electric power steering system, the simulation test method comprising: a HIL system, an electric power steering system performance test bench, a test bench control cabinet and a host, the HIL system comprising an NI real-time system, a CAN communication board, an analog input board, an analog output board, a power supply, a HostPC and a HIL simulator, the electric power steering system performance test bench comprising a device base plate, a steering gear fixing fixture, a steering column fixing fixture, a drive motor, a load motor and a test operating system host computer.

[0006] Preferably, the NI real-time system includes a real-time chassis and a processor board. The HIL system uses a real-time processor to build a real-time simulation system, and runs an IO model and a vehicle model to provide a variable steering wheel angle signal and a load motor load signal to the performance test bench through a simulation output board.

[0007] Preferably, the HIL system programmable power supply provides power for the controller of the electric power steering system, and the HIL system uses an analog input board to collect the steering wheel angle, the output torque of the electric power steering system, and the loads on the left and right sides fed back from the electric power steering system performance test bench.

[0008] Preferably, the HIL system uses a CAN simulation board, which is responsible for simulating other node signals on the vehicle side that communicate with the electric power steering system and receiving the message signals sent by it.

[0009] Preferably, the steering gear fixing clamp is detachably connected to the device base plate, the steering column fixing clamp is connected to the device bracket by bolts and is located at the rear side of the steering gear fixing clamp, the drive motor is located at the rear side of the steering column fixing clamp, and the drive motor is connected to the steering column input shaft.

[0010] Preferably, the method comprises the following steps: Step 1: The host sends control instructions to the HIL simulator, and the HIL simulator downloads the model from the host. The HIL simulator is connected to the electric power steering system performance test bench signal through EPS power supply and CAN signal; Step 2: The electric power steering system performance test bench simulates the electric power steering system, and transmits the test data to the test bench control cabinet for data display, and the test bench control cabinet sends control instructions to the electric power steering system performance test bench; Step 3: The HIL simulator collects signal feedback to the test bench control cabinet, and the test bench control cabinet outputs data signals to the HIL simulator.

[0011] Preferably, in the step one, the electric power steering system performance test bench performs steering wheel angle control of the electric power steering system, and the electric power steering system feeds back the data of the steering wheel torque angle, left tie rod load force control and right tie rod load force to the electric power steering system performance test bench, and in the step three, the signal feedback includes the steering wheel angle, steering wheel torque, left tie rod force, right tie rod force, and the data signal includes the steering wheel angle signal, the left tie rod force signal and the right tie rod force signal.

[0012] Preferably, the electric power steering system performance test comprises the following steps: Step 1: Drive the motor with a sine input of 60° / s and 480° amplitude; Step 2: The load of the load motor changes from 2000N, 1500N, and 1000N at intervals of 10s, with a step length of 500N; Step 3: The vehicle speed is changed from 0 km / h, 20 km / h, and 40 km / h at intervals of 10 seconds, with a step length of 20 km / h, to obtain a test curve.

[0013] Compared with the prior art, the present invention has the following beneficial effects: When the present invention is used, the HIL system sends torque and angular velocity instructions of the incidental operation direction of the vehicle steering wheel to the driving motor through the vehicle model and the preset driving conditions, and sends the load force instruction of the incidental direction of the simulated vehicle load to the load motor, and sends the vehicle end node simulation signal, such as vehicle speed, lateral acceleration, engine working state position, etc. to the electric power steering system assembly through the CAN signal; the electric power steering system assembly is installed and fixed on the performance test bench according to the actual vehicle layout angle, and the real-time consumption current, power torque, angle, angular velocity, electric power steering system working state position and other signals of the electric power steering system assembly are fed back to the HIL system to realize closed-loop testing, and the steering system performance and function test under the simulated actual vehicle environment can be realized, and the load accuracy and response speed are guaranteed by the high-precision load motor, which is close to the actual vehicle test state to the greatest extent, and the accuracy of the test results is improved. The product development cycle is shortened, the test efficiency is improved, and the research and development cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the simulation test structure of the present invention; Figure 2 is a schematic diagram of a first driving motor algorithm of the present invention; Figure 3 is a schematic diagram of a second driving motor algorithm of the present invention; Figure 4 It is a schematic diagram of the first load motor load calculation process of the present invention; Figure 5 It is a schematic diagram of the second load motor load calculation process of the present invention; Figure 6 It is a schematic diagram of the first vehicle speed algorithm flow of the present invention; Figure 7 is a schematic diagram of a second vehicle speed algorithm flow chart of the present invention; Figure 8 It is a parameter curve schematic diagram 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 8, a simulation test method for an electric power steering system, the simulation test method comprising: a HIL system, an electric power steering system performance test bench, a test bench control cabinet and a host, the HIL system comprising an NI real-time system, a CAN communication board, an analog input board, an analog output board, a power supply, a HostPC and a HIL simulator, the electric power steering system performance test bench comprising a device base plate, a steering gear fixing fixture, a steering column fixing fixture, a drive motor, a load motor and a test operating system host computer.

[0017] The NI real-time system includes a real-time chassis and a processor board. The HIL system uses a real-time processor to build a real-time simulation system, and runs an IO model and a vehicle model to provide a variable steering wheel angle signal and a load motor load signal to the performance test bench through a simulation output board.

[0018] The HIL system program-controlled power supply provides power for the controller of the electric power steering system. The HIL system uses an analog input board to collect the steering wheel angle, the output torque of the electric power steering system, and the loads on the left and right sides fed back from the electric power steering system performance test bench.

[0019] The HIL system uses a CAN simulation board to simulate other node signals on the vehicle side that communicate with the electric power steering system and receive the message signals sent by it.

[0020] The steering gear fixing fixture is detachably connected to the device bottom plate, the steering column fixing fixture is connected to the device bracket by bolts and is located at the rear side of the steering gear fixing fixture, the driving motor is located at the rear side of the steering column fixing fixture, and the driving motor is connected to the steering column input shaft, The steering gear fixing fixture is used to fix the steering gear, the steering column fixing fixture is used to fix the steering column, the drive motor provides the steering torque and steering speed that simulate the steering wheel of the actual vehicle, the steering gear outer tie rod is coaxially connected to the high-precision load motors on both sides of the device bottom plate through the connector to ensure 100% load rate, the test operating system host computer implements the test environment simulating vehicle operation based on the simulation instructions of the HIL system, the load motor provides the variable load in the movement of the actual vehicle; the drive motor provides the variable steering wheel torque, steering wheel angle and steering wheel angular velocity in the movement of the actual vehicle.

[0021] A simulation test method for an electric power steering system comprises the following steps: Step 1: The host sends control instructions to the HIL simulator, and the HIL simulator downloads the model from the host. The HIL simulator is connected to the electric power steering system performance test bench signal through EPS power supply and CAN signal; Step 2: The electric power steering system performance test bench simulates the electric power steering system, and transmits the test data to the test bench control cabinet for data display, and the test bench control cabinet sends control instructions to the electric power steering system performance test bench; Step 3: The HIL simulator collects signal feedback to the test bench control cabinet, and the test bench control cabinet outputs data signals to the HIL simulator.

[0022] In step one, the electric power steering system performance test bench performs steering wheel angle control of the electric power steering system, and the electric power steering system feeds back the data of the steering wheel torque angle, the left tie rod load force control and the right tie rod load force to the electric power steering system performance test bench. In step three, the signal feedback includes the steering wheel angle, the steering wheel torque, the left tie rod force and the right tie rod force, and the data signal includes the steering wheel angle signal, the left tie rod force signal and the right tie rod force signal.

[0023] The electric power steering system performance test comprises the following steps: Step 1: Drive the motor with a sine input of 60° / s and 480° amplitude; Step 2: The load of the load motor changes from 2000N, 1500N, and 1000N at intervals of 10s, with a step length of 500N; Step 3: The vehicle speed is changed from 0 km / h, 20 km / h, and 40 km / h at intervals of 10 seconds, with a step length of 20 km / h, to obtain a test curve.

[0024] Among them, the drive motor control algorithm: the model has 4 inputs, 1 is the amplitude, 2 is the sinusoidal wave period calculated according to the angular velocity and amplitude, 3 is the control mode (when the input value is equal to 1, it is the sinusoidal wave control mode, when the value is equal to 2, it is the triangle wave control mode, and when the value is equal to 3, it is the constant value control mode), 4 is the target value that needs to be set in the constant value control mode, and the output is the voltage value obtained by calculation, which is output to the motor control cabinet through the hardware board.

[0025] The specific algorithm is that when the control mode is in sinusoidal mode, the value is added to the set amplitude, where the accumulated step is the set amplitude divided by 1 / 4 period, then subtracted to the negative value of the set step, and then accumulated to 0. It should be noted that since the controlled object is a real motor, the control value does not support jumps. Therefore, when a control mode change is detected at any time, the algorithm will first subtract the current value from 0 and then respond to new control instructions.

[0026] Among them, the load motor control algorithm: the model input is the same as the drive motor algorithm, the control mode is the constant value mode, the output is the voltage value obtained according to the calculation, and it is output to the motor control cabinet through the hardware board.

[0027] The specific algorithm is that when the control mode is in the constant value mode, the value is accumulated to the set value 2000, where the accumulated step is the set amplitude divided by the given rising cycle. If the value is detected to change to, it is then accumulated or accumulated to the new set value. It should be noted that since the controlled object is a real motor, the control value does not support jumps. Therefore, when the control mode change is detected at any time, the algorithm will first decrement the current value to 0 and then respond to the new control command. The control values ​​of the load motors on the left and right sides are opposite.

[0028] Among them, the vehicle speed control algorithm: the vehicle speed changes from 0 km / h, 20km / h, and 40km / h at intervals of 10s, with 20km / h as a step length. The model input is the maximum vehicle speed and the given time required to increase one step length. The output is the vehicle speed value obtained based on the calculation, and is output to the electric power steering system controller through the CAN communication board.

[0029] The specific algorithm is to first keep the value at 0, accumulate to the interval time, and then accumulate to a step length, which is 20 in this example. The accumulated step length is 20 amplitude divided by the given rise time, and then keep the current value for an interval time, and then accumulate to the next step length until it accumulates to the target value. The target value is kept for an interval time and then returns to zero at a uniform speed.

[0030] Among them, the parameter curve obtained from the test shows that the electric power steering system provides power-assist torque, and the hand force torque changes smoothly (the basic power-assist effect increases with the increase of steering wheel torque).

[0031] Working principle: When the present invention is used, the HIL system sends torque and angular velocity instructions of the incidental operation direction of the vehicle steering wheel to the driving motor through the vehicle model and the preset driving conditions, and sends load force instructions of the incidental direction of the simulated vehicle load to the load motor, and sends vehicle end node simulation signals such as vehicle speed, lateral acceleration, engine working status, etc. to the electric power steering system assembly through the CAN signal; the electric power steering system assembly is installed and fixed on the performance test bench according to the actual vehicle layout angle, and the real-time consumption current, power torque, angle, angular velocity, electric power steering system working status, etc. of the electric power steering system assembly are fed back to the HIL system to realize closed-loop testing, and the steering system performance and function test in the simulated real vehicle environment can be realized, and the load accuracy and response speed are guaranteed by the high-precision load motor, which is close to the actual vehicle test state to the greatest extent, and the accuracy of the test results is improved. Shorten the product development cycle, improve test efficiency, and reduce R&D costs.

[0032] 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 simulation test method for an electric power steering system, characterized in that: The simulation test method includes: a HIL system, an electric power steering system performance test bench, a test bench control cabinet and a host, the HIL system includes a NI real-time system, a CAN communication board, an analog input board, an analog output board, a power supply, a HostPC and a HIL simulator, and the electric power steering system performance test bench includes a device base plate, a steering gear fixing fixture, a steering column fixing fixture, a drive motor, a load motor and a test operating system host computer.

2. The electric power steering system simulation test method according to claim 1, characterized in that: The NI real-time system includes a real-time chassis and a processor board. The HIL system uses a real-time processor to build a real-time simulation system, and runs an IO model and a vehicle model to provide a variable steering wheel angle signal and a load motor load signal to the performance test bench through a simulation output board.

3. The electric power steering system simulation test method according to claim 1, characterized in that: The HIL system program-controlled power supply provides power for the controller of the electric power steering system. The HIL system uses an analog input board to collect the steering wheel angle, the output torque of the electric power steering system, and the loads on the left and right sides fed back from the electric power steering system performance test bench.

4. The electric power steering system simulation test method according to claim 1, characterized in that: The HIL system uses a CAN simulation board to simulate other node signals on the vehicle side that communicate with the electric power steering system and receive the message signals sent by it.

5. The electric power steering system simulation test method according to claim 1, characterized in that: The steering gear fixing fixture is detachably connected to the device bottom plate, the steering column fixing fixture is connected to the device bracket by bolts and is located at the rear side of the steering gear fixing fixture, the drive motor is located at the rear side of the steering column fixing fixture, and the drive motor is connected to the steering column input shaft.

6. The electric power steering system simulation test method according to claim 1, characterized in that: The following steps are involved: Step 1: The host sends control instructions to the HIL simulator, and the HIL simulator downloads the model from the host. The HIL simulator is connected to the electric power steering system performance test bench signal through EPS power supply and CAN signal; Step 2: The electric power steering system performance test bench simulates the electric power steering system, and transmits the test data to the test bench control cabinet for data display, and the test bench control cabinet sends control instructions to the electric power steering system performance test bench; Step 3: The HIL simulator collects signal feedback to the test bench control cabinet, and the test bench control cabinet outputs data signals to the HIL simulator.

7. The electric power steering system simulation test method according to claim 6, characterized in that: In the step one, the electric power steering system performance test bench performs steering wheel angle control of the electric power steering system, and the electric power steering system feeds back the data of the steering wheel torque angle, the left tie rod load force control and the right tie rod load force to the electric power steering system performance test bench. In the step three, the signal feedback includes the steering wheel angle, the steering wheel torque, the left tie rod force and the right tie rod force, and the data signal includes the steering wheel angle signal, the left tie rod force signal and the right tie rod force signal.

8. The electric power steering system simulation test method according to claim 1, characterized in that: The electric power steering system performance test comprises the following steps: Step 1: Drive the motor with a sine input of 60° / s and 480° amplitude; Step 2: The load of the load motor changes from 2000N, 1500N, and 1000N at intervals of 10s, with a step length of 500N; Step 3: The vehicle speed is changed from 0 km / h, 20 km / h, and 40 km / h at intervals of 10 seconds, with a step length of 20 km / h, to obtain a test curve.

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