A Hardware-in-the-Loop Test System and Method for the Composite Braking of In-Wheel Motors Based on Fault Injection

Abstract

The present invention discloses a hub motor composite braking Hil test system and method based on fault injection, including a servo motor real-time dynamic vertical loading system, a flywheel box, a speed reducer, a drum part, a simulated cockpit, an electromechanical braking system, an electric wheel system, and a fault injection system. The real motion condition of the electric wheel module on the road surface is simulated to obtain parameters such as its power performance, braking performance, reliability, and durability, and verification is carried out through relevant standards of the electric wheel and the motor, etc.; a fault simulation system is equipped for the fault simulation test of the EMB test system to ensure the reliability of the electromechanical braking system. For the electrical part, mainly a PCI board is used in cooperation with the NI board to control the dynamometer, the vertical loading system, and the electric wheel. In the present invention, through automatic control, the fault triggering is completely controlled by the script programmed by the upper computer, and there is no need to manually conduct on-off tests on signals, short-circuit tests between the ground and the power supply, and short-circuit tests between signals.

Description

Technical Field

[0001] The present invention belongs to the technical field of automotive braking, and particularly relates to a method for a hub motor composite braking Hil test system based on fault injection. Background Art

[0002] With the rapid development of automotive intelligence, automotive by-wire technology has emerged and has been widely applied in vehicles. It is a new control system based on information interaction systems and real-time control. EMB (Electromechanical Braking) replaces the hydraulic circuit with an electromechanical system, mainly consisting of a pedal simulator, an EMB actuator, and a controller, etc., and realizes braking by controlling the clamping force of the actuator. The EMB system has a simple structure, rapid braking response, high braking energy efficiency, high sensitivity, and is easy to integrate and control with other systems. Its braking force distribution unit uses an electronic control unit, which can reasonably distribute braking force according to the driver's braking situation to ensure vehicle stability.

[0003] As a new type of braking method, the basic structure of the traditional braking system test bench is inconsistent with that of the automotive electromechanical braking system, and its functions are single, which can no longer meet the usage requirements. EMB will surely have a broad market in future vehicles. However, EMB has a mechanical structure and requires an additional braking failure backup mechanism. Conducting research on EMB with fault tolerance functions has positive significance for enhancing the competitiveness of the new field of braking technology in our country. Summary of the Invention

[0004] The purpose of the present invention is to provide a test bench for an automotive electromechanical braking system with hil simulation and fault injection to overcome the above deficiencies.

[0005] The hub motor composite braking Hil test system with fault injection includes a mechanical part and an electrical part;

[0006] The mechanical part includes a servo motor real-time dynamic vertical loading system (3), an inertia part (flywheel box) (9), a speed increasing box (8), a drum (7), a braking actuator (1), an electric wheel (2), a driver's cab (13), an operation console (12), a clutch (11), a brake disc (4), a torque meter (6), and a dynamometer (5). As Figure 1 shown.

[0007] The dynamometer (5), torque meter (6), drum (7), speed increasing box (8), and inertia part (flywheel box) (9) in this hub motor composite braking Hil test system are fixed on a large cast iron base plate. The electric wheel system (2) is connected to the brake disc (4) and the vertical loading system through bearings and is placed directly above the drum (7).

[0008] The brake actuator (1) fixes the brake assembly onto the brake disc (4) between the gantry bracket and the electric wheel module. The EMB-ECU controls the drive motor according to the required braking clamping force output by the upper-layer controller BCU. The output torque of the drive motor is amplified by the reduction mechanism and then transmitted to the motion conversion mechanism. The motion conversion mechanism converts the rotational motion into a linear motion to push the brake caliper body and clamp the brake disc, thereby generating a braking torque to brake and decelerate the electric wheel (2).

[0009] The electric wheel (2) is installed on the gantry bracket (16) and contacts the drum (7), and can simulate the power and braking performance under actual road conditions. The up-and-down movement of the electric wheel is controlled by a linear slide rail, and the position of the electric wheel (2) is fixed by an electric wheel fixing tooling.

[0010] The servo motor real-time dynamic vertical loading system (3) is located under the electric cylinder and fixed to the gantry bracket through an adapter plate, and spans above the drum (7). The system uses an electric cylinder to achieve the vertical loading of the electric wheel, and is equipped with a high-precision pressure sensor to accurately measure the vertical load applied to the electric wheel in real time.

[0011] The electric cylinder (14) is fixed to the gantry bracket (16) through an adapter plate and spans above the drum (7). The linear slide rail (15) is installed on the gantry bracket. The electric wheel module and its fixing tooling, the pressure sensor and the electric cylinder are connected at the center of the gantry bracket and can move up and down along with the linear slide rail.

[0012] The drum part (7) is installed on the large cast iron base plate through bearings and supports. To meet the needs of simulating various road surfaces during system testing, a series of threaded holes are drilled at both edges of the circumferential surface of the drum, facilitating the installation of thin parts / wrappings of different materials onto the drum surface with screws, thereby changing the adhesion coefficient of the system-simulated road surface and adapting to different braking conditions.

[0013] The flywheel box (9) is connected to the clutch (11) at one end through a bearing and to the speed increasing wheel (8) at the other end, and is used to increase the moment of inertia of the drum. When the drum needs to increase its inertia, the inertia disc in the flywheel box is screwed onto the shaft with bolts so that the inertia disc and the shaft rotate together. When the inertia disc is not needed, the bolts are unscrewed and the inertia disc is fixed to the bottom plate of the square tube welding frame with a bracket.

[0014] The dynamometer (5) is located at both ends of the test system and is connected to the torque meter (6) and the drum (7) through bearings. It receives the analog signal sent by the Advantech industrial computer and is connected to the NI real-time system. The driver's cab and the operation console face the test bench.

[0015] The electrical part is mainly the control of the dynamometer, vertical loading system and electric wheel by Advantech industrial computer in conjunction with NI board. NI board includes frequency input, analog input and output, serial port, Ethernet and CAN. NI real-time system matching board includes analog input CAN1 and CAN2. In terms of actuator control, the dynamometer and vertical loading system are controlled by analog output board PCI-1724U, and the drive wheel is controlled by CAN communication using CAN communication board PCI-9820CAN; in terms of signal acquisition, the torque signal is obtained by pulse input board PCI-1780, and the voltage and current signals are obtained by analog input board PCI-1712. The bearing temperature, cooling water pressure, cooling water temperature and vibration signals are controlled by temperature instrument. Safety emergency stop system, gear lubrication control is controlled by PLC. Such as Figure 2 Shown

[0016] The electrical part uses Advantech industrial computer + Advantech board + PLC. The Advantech board is inserted into the Advantech industrial computer to control the analog output, analog input, frequency input and serial port, Ethernet, and CAN communication of this electrical system. The dynamometer system uses the Advantech board to control the speed and torque of the system to simulate road resistance and slope resistance. The speed and torque signals of the torque meter are collected by the pulse input board and fed back to the Advantech industrial computer in real time. The safety emergency stop system is directly controlled by the PLC to avoid safety accidents. The vertical loading system (3) mainly consists of an electric cylinder and a tension and pressure sensor. The Advantech board controls the servo motor to dynamically load vertically in real time to simulate the up and down jumping of the electric wheel when driving on the road. The mechanical braking system controls the drive motor through the Advantech board according to the required braking force.

[0017] This test bench has added a fault simulation system based on the mechanical and motor systems. The fault simulation system includes a signal conditioning system and a fault injection system. This system controls the fault simulation part of this experiment. The main function of the fault simulation system is to perform fault simulation tests in the emb brake test bench. The signal conditioning system realizes signal conditioning between 24V and 5V voltages, between 4-20mA and voltage signals, between switch IO signals, and between analog signals. Through signal conditioning, various detected signals are converted into standard signals, mainly including debouncing, filtering, protection, level conversion, isolation, etc. The fault simulation system has software fault injection and hardware fault injection functions, such as Figure 4 shown.

[0018] The fault simulation system is connected to the test control system through the IO port. The test control system includes the test computer (Advantech industrial computer IPC) and the EMB test bench. The test control system is connected to the NI Rio real-time simulator (real-time simulation system) through TCP. Figure 5 、 Figure 6 shown.

[0019] The function of the fault injection system is as follows: on the premise that the basic components work safely, a fault simulation system is inserted between the control circuit and the basic components, and faults are injected through software and hardware means to simulate the fault phenomena of the basic components. The fault injection system has functions such as simulating faults of control components, sensors, and actuators. The CAN communication card can control the CAN intelligent conditioning module in the signal conditioning unit to inject soft faults in the sensor acquisition module and simulate faults such as hysteresis and jitter of control components that cannot be simulated by hardware.

[0020] Since sensors are precision electronic components and are in a harsh working environment, their reliability is lower than that of mechanical faults. Once a problem occurs, the fault information is introduced into the closed-loop control, directly affecting the braking force control quality. In severe cases, it will cause the brake to fail, and the probability of its error is relatively high compared to other faults.

[0021] The fault injection software realizes hardware fault injection by controlling the fault simulation card through the PxI bus; the fault injection software realizes software and hardware fault injection by controlling the CAN intelligent conditioning module through the CAN bus; the fault injection software controls the programmable power supply through the LAN to complete two types of hardware fault injection, and the fault injection software sends the operation instructions and data generated during the test to the database for storage through the LAN.

[0022] Three main hardware faults for EMB actuator fault injection: aspects of the controller and motor, sensors, and the execution structure.

[0023] The software is based on the labview platform and adopts a modular design, integrating functions such as data simulation, sending, acquisition, data processing, control, and communication, to realize the injection, location, and analysis of different types of software and hardware faults. The software part of the fault injection system is designed based on the Labview platform and has a good human-computer interaction interface. Users can manually or automatically execute injection instructions according to a predetermined program on the fault injection software interface, and can also receive fault injection instructions from systems such as simulation through the network to complete the fault channels and fault parameters. At the same time, after the fault signal injection is completed, the data analysis and processing part can support automatic identification of bus signal ICD file data, record the bus configuration, and complete the import and export of files in formats such as Excel and TXT.

[0024] Through the NI RIO real-time system, the rotational speed torque signal, temperature signal, vibration signal, and braking pressure signal are collected in real time and transmitted to the upper computer for data processing and analysis, and then instructions are sent to control each system.

[0025] All the hardware of the vehicle and the braking system is connected to the simulation loop, enabling real-time data interaction between the simulation model and the actual system, and improving the simulation confidence. This test bench console, Carsim, Simulnk, Labview, wires, signal transmitters and receivers, etc. At the same time, a vehicle and pneumatic braking system model and simulation can be established, which can interact with the hardware part.

[0026] Among them, the size of the electric wheel test bench can enable the braking system to be arranged proportionally on this test bench according to the vehicle layout; the test bench can accommodate the assembly requirements of different braking systems such as ABS, EBS, ESC, and EPB, as well as different EMB brake structures and other components.

[0027] A test method for a hub motor composite braking Hil test system based on fault injection includes:

[0028] 1. Fault injection test

[0029] The first step: The test management control software remotely notifies the fault injection system and the test general control computer to start the test through the network;

[0030] The second step: After the fault injection system and the test general control computer set the corresponding parameters, they start the corresponding fault injection test for the specified fault type;

[0031] Fault simulation method: During the voltage regulation process, the fault injection software controls the relay of the fault simulation board to cut off the speed signal from the CAN intelligent conditioning, making the speed signal invalid;

[0032] The third step: During the fault injection process, the fault injection system injects faults and uploads the fault information to the real-time simulation system; at the same time, the test general control computer collects data of various sensors;

[0033] The fourth step: Write the data into the database through the network and display the corresponding data in the form of charts and curves on the software interface;

[0034] 2. Hub motor electronic braking simulation test

[0035] The first step: The real-time simulation system integrally develops a vehicle simulation model, and uses the vehicle simulation model to run in real time;

[0036] The second step: The test general control computer is connected to the NI Rio real-time simulation machine through TCP. The test general control computer downloads the compiled model to the real-time simulation machine. The real-time simulation machine runs the model in real time and transmits the simulation data to the test computer in real time. The test general control computer can modify the parameters of the model in the real-time simulation machine in real time through the network cable;

[0037] 3. For the fault injection process based on hardware-in-the-loop simulation

[0038] Step 1: Set the vehicle operating conditions, braking system function mode, and CAN communication fault type

[0039] Step 2: Conduct tests:

[0040] 1) Hardware connection: Connect the upper computer to the PXI chassis with a network cable, connect the PXI chassis to the corresponding wiring harness of the test bench, and supply power to the entire test device;

[0041] 2) Configure the vehicle parameters in Carsim according to the model of the vehicle under test, and set the road scenario and test conditions in Carsim

[0042] according to the test cases;

[0043] 3) Compile the model: Select the hardware channels that need to inject faults in ConfigurationDesk, and then compile the Simulink model that has been built and configured with input and output interfaces;

[0044] 4) Conventional function test: Enter the test session in Carsim, set parameters and record data in ControlDesk according to the function to be tested and the test cases, control the brake pedal through CANopen in ControlDesk to apply brakes, observe whether the corresponding functions are triggered and the vehicle state after triggering, and change the vehicle speed according to the test cases and change different steering wheel angles through CAN signals to complete multiple groups of tests under different working conditions;

[0045] 5) Fault injection test: Implement the injection of fault information according to the fault injection test steps, observe and record the experimental data, change the relevant parameters according to the requirements of the test cases and repeat the above tests to complete the tests under different working conditions.

[0046] Advantages of the present invention:

[0047] 1. Overall effect of the present invention: The fault injection-based in-wheel motor composite braking Hil test system designed and developed by the present invention can conduct braking performance and durability tests on in-wheel motor composite braking, and the obtained product performance data can be used as a test reference for researchers to develop and design EMB braking modules, accelerating the product development and optimization.

[0048] 2. The Emb braking test bench based on fault injection proposed by the present invention can simulate fault modules, consider the faults that may occur in the traditional braking test process for simulation testing. This method can test the fault tolerance of emb brakes, filling the gap in existing test methods and meeting the market demand for simulation testing equipment for new energy vehicle EMB braking modules.

[0049] 3. The fault injection system of the present invention can meet the requirements for the automated testing of the device under test according to the fault signals. By setting up fault injection, it can meet the testing requirements of the electric wheel hub motor at low cost. And by setting up an automated control system, the fault triggering is completely controlled by the script run by the host computer, eliminating the need for manual on-off testing of signals, short-circuit testing between the signal and the ground or power supply, and short-circuit testing between signals.

[0050] 4. The fault injection method of the present invention more intuitively shows the impact of EMB-level and system-level faults on the vehicle level, enabling more accurate definition of the functional safety objectives and their attribute values of the system, making up for the deficiencies of traditional safety analysis methods, and helping engineers to reasonably design subsequent safety control strategies and fault-tolerant control algorithms. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a mechanical schematic diagram of the electro-mechanical braking test system for the hub motor;

[0052] Figure 2 It is an electrical schematic diagram of the electro-mechanical braking test system for the hub motor;

[0053] Figure 3 Mechanical structure diagram of the vertical loading system;

[0054] Figure 4 It is a schematic diagram of the composition of the fault simulation system;

[0055] Figure 5 It is a schematic diagram of the fault injection information flow;

[0056] Figure 6 It is a schematic diagram of the information flow of the fault simulation system. DETAILED DESCRIPTION OF THE INVENTION

[0057] The present invention discloses a hub motor composite braking Hil test system and method based on fault injection, including a servo motor real-time dynamic vertical loading system, a flywheel box, a speed reducer, a drum part, a simulated cockpit, an electro-mechanical braking system, an electric wheel system, and a fault injection system. It simulates the real movement of the electric wheel module on the road surface to obtain parameters such as its power performance, braking performance, reliability, and durability, and verifies them according to relevant standards for electric wheels and motors. It is equipped with a fault simulation system for fault simulation tests of the EMB test system to ensure the reliability of the electro-mechanical braking system. For the electrical part, mainly PCI boards cooperate with NI boards to control the dynamometer, the vertical loading system, and the electric wheel. Through automated control, the fault triggering of the present invention is completely controlled by the script run by the host computer, eliminating the need for manual on-off testing of signals, short-circuit testing between the signal and the ground or power supply, and short-circuit testing between signals.

[0058] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0059] The specific functions of the system are as follows:

[0060] The real-time simulator interacts with the simulation display system and serves as the data input for the data display of the electro-mechanical braking test of the electric wheel and the three-dimensional animation display from multiple angles. The real-time simulator interacts with the simulation host computer, and the simulation host computer runs the test software to realize the real-time monitoring of the vehicle model and the braking model. The test management console can control the test software of the simulation host computer to start running or stop, and the real-time simulator transmits the test data to the database of the test system.

[0061] 1. Fault injection test

[0062] The first step: The test management control software remotely notifies the fault injection computer and the test master computer to start the test through the network.

[0063] The second step: After the fault injection system and the test master system set the corresponding parameters, they start the corresponding fault injection test for the specified fault type.

[0064] The third step: During the fault injection process, the fault injection computer injects the fault and uploads the fault information to the real-time simulation system; at the same time, the test computer collects various sensors.

[0065] The fourth step: Write the data into the original database through the network and display the corresponding data in the form of charts and curves on the software interface.

[0066] 2. Hub motor electronic braking simulation test

[0067] The hub motor electronic braking simulation test is completed by the Hil real-time simulation system.

[0068] The first step: The real-time simulation system integrally develops the vehicle simulation model, and runs the vehicle simulation model in real time.

[0069] The second step: The test computer is connected to the NI Rio real-time simulator through TCP. The test computer downloads the compiled model to the real-time simulator. The real-time simulator runs the model in real time and transmits the simulation data to the test computer in real time. The test computer can modify the parameters of the model in the real-time simulator in real time through the network cable.

[0070] 3. Fault injection test

[0071] The fault injection test is one of the hardware-in-the-loop tests of the in-wheel motor composite braking Hil test bench for this fault injection. The fault injection test inserts a fault simulation system between the electrical system and the EMB mechanical system on the premise that the EMB mechanical components work safely, and injects faults through software means to simulate the fault phenomena of the mechanical components.

[0072] Examples of simulated faults are as follows:

[0073] (1) Simulated fault: Motor speed signal fault

[0074] Fault phenomenon: The failure of the speed signal affects the motor, and the fault information is introduced into the closed-loop control.

[0075] Possible causes of the fault: The light slit of the grating plate is blocked; the connector is poorly contacted, the bearing is damaged; the coupling is broken, the cable is loosely connected, the cable is completely broken, etc.

[0076] Fault simulation method: During the voltage regulation process, the fault injection software controls the relay of the fault simulation board to cut off the speed signal from the CAN intelligent conditioning, making the speed signal invalid.

[0077] 4. For the fault injection process based on hardware-in-the-loop simulation

[0078] The first step: According to the vehicle operating conditions, such as vehicle speed, acceleration, and road conditions; the functional modes of the braking system, such as ABS and ESC; the types of CAN communication faults, including CAN communication line faults and CAN communication messages.

[0079] Signal errors; types of sensor failure faults, including open circuit, short circuit, progressive faults, gradual faults, and sudden faults are combined to generate test cases;

[0080] The second step: Conduct the test:

[0081] Step 1. Hardware connection: Connect the upper computer to the pxi chassis with a network cable, connect the pxi chassis to the corresponding wire harness of the test bench, and supply power to the entire test device;

[0082] Step 2. Configure the vehicle parameters in Carsim according to the model of the vehicle under test, and set the road scene and test conditions in Carsim according to the test cases;

[0083] Step 3. Compile the model: Select the hardware channels that need to inject faults in ConfigurationDesk,

[0084] Then compile the Simulink model that has been built and configured with input and output interfaces;

[0085] Step 4. Routine function test: Enter the test session in Carsim, set parameters and record data according to the function to be tested and test cases in ControlDesk, control the brake pedal for braking through CANopen in ControlDesk, observe whether the corresponding function is triggered and the vehicle state after triggering, and change the vehicle speed according to the test cases and change different steering wheel angles through CAN signals to complete multiple groups of tests under different working conditions;

[0086] Step 5. Fault injection test: Implement the injection of fault information according to the fault injection test steps, observe and record the experimental data, change the relevant parameters according to the requirements of the test cases and repeat the above tests to complete the tests under different working conditions;

[0087] In summary, in the fault injection test experiment based on the Hil platform in this embodiment, various fault signals are simulated and generated by the simulation module, so that the control module controls the corresponding DUT to implement automated testing according to the fault signals, thereby ensuring that the fault injection Hil test system meets the test requirements; in addition, the control module can be controlled according to various fault signals.

[0088] 5. Implement automated testing on the corresponding DUT, thereby ensuring resource allocation. The automatic control method does not require manually conducting on-off tests on signals, short-circuiting to ground or to the power supply, or short-circuiting between signals. Avoid manual operation of the BOB junction box by personnel.

[0089] 6. In the hub motor electro-mechanical brake test bench hil simulation system described above, the fault simulation system includes a signal conditioning system and a fault injection system. The main function of the fault simulation system is to conduct fault simulation tests in the emb brake test bench. The signal conditioning system realizes signal conditioning between +24V and 5V voltages, between 4 - 20mA and voltage signals, between digital IO signals, and between analog signals. The fault injection system has software fault injection and hardware injection fault functions.

[0090] The fault injection test is to insert a fault simulation system between the control circuit and the basic components on the premise that the basic components work safely, inject faults through software and hardware means to simulate the fault phenomena of the basic components. The fault injection system has functions such as simulating faults of control components, sensors, and actuators. The CAN communication card can control the CAN intelligent conditioning module in the signal conditioning unit to inject soft faults in the sensor acquisition module to simulate faults such as control component hysteresis and jitter that cannot be simulated by hardware.

[0091] Since the sensor is a precision electronic component and operates in a harsh environment, its reliability is lower than that of mechanical failures. Once a problem occurs, the fault information is introduced into the closed-loop control, directly affecting the braking force control quality. In severe cases, it will cause the brake to fail, and the probability of its error is relatively high compared to other faults.

[0092] Since the sensor is a precision electronic component and operates in a harsh environment, its reliability is lower than that of mechanical failures. Once a problem occurs, the fault information is introduced into the closed-loop control, directly affecting the braking force control quality. In severe cases, it will cause the brake to fail, and the probability of its error is relatively high compared to other faults.

[0093] The fault injection software realizes hardware fault injection by controlling the fault simulation card through the PxI bus; the fault injection software realizes software and hardware fault injection by controlling the CAN intelligent conditioning module through the CAN bus; the fault injection software completes two types of hardware fault injection by controlling the programmable power supply through the LAN, and the fault injection software sends the operation instructions and data generated during the experiment to the database for storage through the LAN.

[0094] Three main hardware faults for EMB actuator fault injection: in terms of the controller and motor, sensors, and actuator structure;

[0095] The NI RIO real-time system is used to collect the rotational speed and torque signals, temperature signals, vibration signals, and braking pressure signals in real time, transmit them to the upper computer for data processing and analysis, and then issue control instructions to each system.

[0096] All the hardware of the whole vehicle and the braking system are connected to the simulation loop, which can realize real-time data interaction between the simulation model and the actual system, and improve the simulation confidence. This test bench console, carsim, simulink, Labview, wires, signal transmitters and receivers, etc. At the same time, a model and simulation of the whole vehicle and the air braking system can be established, which can interact with the hardware part.

[0097] In the electrical structure, mainly the PCI board is used in cooperation with the NI board to control the dynamometer, the vertical loading system, and the electric wheel. In terms of the control of the actuators, the dynamometer and the vertical loading system are controlled by the analog output board PCI-1724U, and the drive wheel is controlled by the CAN communication board PCI-9820CAN through CAN communication; in terms of signal acquisition, the torque signal is obtained through the pulse input board PCI-1780, the voltage and current signals are obtained by the analog input board PCI-1712, and the control bearing temperature, cooling water pressure, cooling water temperature, and vibration signals are collected by the temperature instrument. The safety emergency stop system and the gear lubrication are controlled by the PLC.

[0098] Among them, the size of the electric wheel test bench can accommodate the assembly requirements of different braking systems such as ABS, EBS, ESC, and EPB, as well as different EMB brake structures and other components.

[0099] The series of detailed descriptions listed above are only specific descriptions of the feasible implementation modes of the present invention, and they are not intended to limit the protection scope of the present invention. Any equivalent modes or changes that do not depart from the technology created by the present invention should be included within the protection scope of the present invention.

Claims

1. A hub motor composite braking Hil test system based on fault injection, characterized in that It includes a mechanical part and an electrical part; the mechanical part includes a vertical loading system (3), a flywheel box (9), a speed increasing box (8), a drum (7), a brake actuator (1), an electric wheel (2), a test bench (13), an operation console (12), a clutch (11), a brake disc (4), a torque meter (6), and a dynamometer (5); The dynamometer (5), torque meter (6), drum (7), speed increasing box (8), and flywheel box (9) are fixed on a large cast iron base plate. The electric wheel (2) is connected to the brake disc (4) and the vertical loading system (3) through bearings and is placed directly above the drum (7); The brake actuator (1) fixes the brake assembly on the brake disc (4) between the gantry bracket and the electric wheel; The electric wheel (2) is installed on the gantry bracket (16), contacts the drum (7), and can simulate the power and braking performance under actual road conditions; The vertical loading system (3) is located under the electric cylinder, is fixed on the gantry bracket through an adapter plate, and spans above the drum (7); Part of the drum (7) is installed on the large cast iron base plate through bearings and supports; One end of the flywheel box (9) is connected to the clutch (11) through a bearing, and the other end is connected to the speed increasing box (8); The dynamometer (5) is located at both ends of the system and is connected to the torque meter (6) and the drum (7) through bearings; The electrical part is used to provide a simulated scenario required for the test, inject a fault signal, control the corresponding sample under test according to the fault signal, and achieve automated testing; It also includes a fault simulation system, including a signal conditioning system and a fault injection system. This fault simulation system is used to conduct fault simulation tests in the EMB brake test bench; Among them, the signal conditioning system realizes signal conditioning between +24V and 5V voltages, between 4 - 20mA and voltage signals, between digital I / O signals, and between analog signals, and converts various detected signals into standard signals, including debouncing, filtering, protection, level conversion, and isolation; The function of the fault injection system is: on the premise that the basic components work safely, insert the fault simulation system between the control circuit and the basic components, inject faults through software and hardware methods to simulate the fault phenomena of the basic components. The fault injection system has the function of simulating faults of control components, sensors, and actuators. The CAN communication card can control the CAN intelligent conditioning module in the signal conditioning system to inject soft faults during sensor acquisition and simulate faults such as control element hysteresis and jitter that cannot be simulated by hardware.

2. The composite braking Hil test system for in-wheel motors based on fault injection according to claim 1, characterized in that, The brake actuator (1) controls the drive motor according to the required braking clamping force output by the upper - layer controller BCU (EMB - ECU). The output torque of the drive motor is amplified by a reduction mechanism and then transmitted to a motion conversion mechanism. The motion conversion mechanism converts the rotational motion into a linear motion to push the brake caliper body and clamp the brake disc (4), generating a braking torque to brake and decelerate the electric wheel (2).

3. The composite braking Hil test system for in-wheel motors based on fault injection according to claim 1, characterized in that, The electric wheel (2) can be controlled to move up and down through a linear slide rail, and an electric wheel fixing tooling is used to fix the position of the electric wheel (2).

4. The composite braking Hil test system for in-wheel motors based on fault injection according to claim 3, characterized in that, The linear slide rail (15) is installed on the gantry bracket, and the electric wheel and its fixing fixture, the pressure sensor and the electric cylinder are connected at the center of the gantry bracket and can move up and down with the linear slide rail.

5. The composite braking Hil test system for in-wheel motors based on fault injection according to claim 1, characterized in that, The system uses an electric cylinder to realize vertical loading of the electric wheel, and combines a pressure sensor to accurately measure the vertical load applied to the electric wheel in real time.

6. The composite braking Hil test system for in-wheel motors based on fault injection according to claim 5, wherein The electric cylinder (14) is fixed on the gantry bracket (16) through an adapter plate and spans above the roller (7).

7. The composite braking Hil test system for in-wheel motors based on fault injection according to claim 1, wherein, Threaded holes are provided on both sides of the circumferential surface of the drum to facilitate the installation of thin parts / wrappings of different materials on the drum surface with screws, thereby changing the adhesion coefficient of the system's simulated road surface to adapt to different braking conditions.

8. A hub motor composite braking Hil test system based on fault injection according to claim 1, characterized in that, The aforementioned system utilizes Advantech industrial computers, Advantech boards, and a PLC. The Advantech boards are inserted into the industrial computer to control the electrical system's analog output, analog input, frequency input, and serial, Ethernet, and CAN communications. The dynamometer system uses the Advantech boards to control the speed and torque of the system to simulate road and grade resistance. The torque meter's speed and torque signals are collected by the pulse input board and fed back to the Advantech industrial computer in real time. Safety emergency stop is controlled by PLC to avoid accidents; The vertical loading system (3) consists of an electric cylinder and a tension and pressure sensor. The Advantech board controls the servo motor to dynamically load vertically in real time to simulate the up and down bouncing of the electric wheel when driving on the road. The mechanical braking system controls the drive motor through the Advantech board according to the required braking force.

9. A test method for a hub motor composite braking Hil test system based on fault injection, characterized in that, include: Step 1. Fault injection test Step 1: The test management and control software remotely notifies the fault injection system and the test master control computer via the network to start the test; Step 2: After the fault injection system and the test control computer set the corresponding parameters, the corresponding fault injection test for the specified fault type begins; Fault simulation method: During the voltage regulation process, the fault injection software controls the fault simulation board relay to cut off the speed signal from the CAN intelligent conditioning, making the speed signal invalid; Step 3: During the fault injection process, the fault injection system injects the fault and uploads the fault information to the real-time simulation system; at the same time, the test control computer collects data from various sensors; Step 4: Write the data into the database through the network and display the corresponding data in the form of charts and curves on the software interface; Step 2. Hub motor electronic brake simulation test Step 1: Real-time simulation system integration develops a whole vehicle simulation model, uses the whole vehicle simulation model and runs it in real time; Step 2: The test control computer is connected to the NI Rio real-time simulator via TCP. The test control computer downloads the compiled model to the real-time simulator. The real-time simulator runs the model in real time and transmits simulation data to the test computer in real time. The test control computer can modify the parameters of the model in the real-time simulator in real time through the network cable. Step 3. Fault injection process based on hardware-in-the-loop simulation Step 1: Set vehicle operating conditions, brake system function mode, and CAN communication fault type Step 2: Test: 1) Hardware connection: Connect the host computer and the PXI chassis with a network cable, connect the PXI chassis to the corresponding wiring harness of the test bench, and power the entire test device; 2) Configure the vehicle parameters in Carsim according to the model of the test vehicle, and set the road scenario and test conditions in Carsim according to the test cases. 3) Compile the model: Select the hardware channels for which fault injection is required in ConfigurationDesk, and then compile the Simulink model that has been built and configured with input and output interfaces. 4) Conduct regular function tests: Enter the test phase in Carsim, set parameters and record data in ControlDesk according to the functions to be tested and the test cases, control the brake pedal through CANopen in ControlDesk to apply brakes, observe whether the corresponding functions are triggered and the vehicle status after triggering, and change the vehicle speed according to the test cases and change different steering wheel angles through CAN signals to complete multiple groups of tests under different working conditions. 5) Conduct fault injection tests: Implement the injection of fault information according to the fault injection test steps, observe and record the experimental data, change the relevant parameters according to the requirements of the test cases, repeat the above tests, and complete the tests under different working conditions. ​

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