Overview of various automotive controllers-Chip recycling network

Scheme of various control units for automobiles
The control systems of automobiles are divided into three categories: comfort systems, safety systems, and power systems

1. Body Control Unit (BCM):The Body Control Unit (BCM) is suitable for working in both 12V and 24V voltage environments and can be used for body control of sedans, buses, and commercial vehicles. The input module collects various switch and analog information inputs through a collection circuit, while the LIN receiving module receives control handle unit signals (such as lights, wipers, washing, etc.). The output module adopts power drive and relay drive, which has good cost-effectiveness. The CAN communication module achieves information exchange with other automotive electronic modules. The main implementation of vehicle door control includes door locks, various lights, front and rear washing, front and rear wipers, electric windows, and other controls. Implemented NM (CAN) network management, UDS diagnosis, CCP calibration and other functions on the software and passed DV experiments.

2. EPS electronic power steering systemEPS is a system that provides auxiliary steering power. When the driver controls the steering wheel for steering, the torque sensor detects the direction of the steering wheel and the magnitude of the torque, and sends a voltage signal to the electronic control unit. The electronic control unit sends commands to the electric motor controller based on the torque sensor's detected torque voltage signal, rotation direction, and vehicle speed signal, causing the electric motor to output steering assistance torque of corresponding size and direction, thereby generating auxiliary power.

3. Steering wheel angle sensor (SAS)The steering wheel angle sensor is used to detect the steering wheel angle and speed during vehicle driving, providing signals for other vehicle control systems such as ESC, EPS, AFS, etc. The developed steering wheel angle sensor is based on the giant magnetic field effect and has good performance in measurement accuracy, resolution, linearity, service life, and other aspects. The Infineon dual sensor scheme is used, and after correct calibration and initialization, the angle information is not lost during power failure, thus the absolute angle position can be output within the range. This project was developed by Tsinghua University and is divided into two forms, A and B, depending on the installation size and location. The principle structure is shown in the following figure.

4. Electronic Parking Brake System (EPB)The electronic parking brake system is a technology that uses electronic control to achieve parking braking. It integrates temporary braking during driving and long-term braking after parking. The control method has changed from mechanical handbrake lever to electronic mechanical control. The structure and principle of EPB are shown in the figure.
The EPB electronic control unit developed in this project has two versions, which are suitable for single motor cable type and dual motor integrated clamp type EPBs. The electronic control unit adopts a dual CPU scheme of main CPU and safety monitoring CPU to improve the reliability of the system. The electronic control unit collects relevant signals, controls the motor and mechanical actuator to respectively achieve four functions: temporary parking brake, hill start assist, dynamic emergency brake, and automatic parking (Autohold).

5. Electronic Stability System ESP
It is applicable to the body electronic stability system to correct the excessive steering or understeer of the vehicle, and actively intervene to ensure the stability of vehicle handling.
The ESP system determines the driver's intention and the driving status of the vehicle by collecting wheel speed signals, brake master cylinder pressure signals, brake switch signals, steering wheel angle signals, yaw and acceleration signals, etc. Through measures such as solenoid valve and pump motor control, engine and transmission control adjustment, it applies braking force on suitable wheels to generate corrective torque on the vehicle, To correct the phenomenon of excessive steering or understeer caused by the vehicle, and actively intervene to ensure the stability of vehicle handling. The structural composition is shown in the following figure.

6. Electric power steering system electronic control unit EPSThis electronic control unit is suitable for application in a 12V power supply environment and can be used for steering control of sedans and pure electric vehicles. The main control MCU adopts Infineon's XC2300 series microcontroller, which collects vehicle status information such as engine speed signal, vehicle speed signal, torque sensor signal, ignition signal, etc., and sends it to the controller ECU for comprehensive analysis, judgment, and calculation before outputting a current signal to control the EPS motor. The EPS motor generates assistance torque through the transmission mechanism, which is applied to the steering shaft to assist the driver in completing the steering operation. The steering control of this system is lightweight at low speeds, and has small steering assistance at high speeds, ensuring smooth and non drifting handling. The structural composition is shown in the following figure.

7. Vehicle Controller (VCU)VCU collects driver control information, vehicle operation information, engine, motor, battery, gearbox data, and feedback information from various subsystems, and sends control commands to each subsystem through calculation, thereby achieving VCU control of the entire vehicle. The strategy of the vehicle controller is to combine electric motors, batteries, and engines to drive the vehicle under different operating conditions, achieving the best efficiency. The processor adopts Infineon's 32-bit processor TC1728N.

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