Impact on Vehicle Performance
The vehicle control system optimizes engine and motor torque output, enhancing vehicle power and efficiency. Additionally, the system continuously monitors the status of each component, promptly addressing potential safety risks to ensure the safety of the vehicle and its occupants. Furthermore, the vehicle control system integrates and manages the functions of various vehicle components, improving driving comfort and overall vehicle coordination.
Vehicle Control Unit (VCU)
- Functions of the VCU
The VCU is the core of the control system, responsible for data exchange, safety management, and energy distribution. Its functions are prioritized and implemented in the following order:
Data Exchange Management: The VCU collects real-time information from the driver’s inputs and the operational status of each component, receiving data from the CAN bus and sending control commands via the CAN bus. It also provides drive signals to display units, relays, etc., through I/O, D7A, and PWM.
Safety and Fault Management: The VCU analyzes and processes potential vehicle faults, making necessary adjustments when errors are detected, ensuring vehicle safety while meeting the driver's demands.
Driver Intention Layer: The VCU interprets the driver’s commands, calculating the target torque and required power to fulfill the driver’s intent.
Energy Flow Management: The VCU allocates the required power among multiple energy sources, optimizing fuel efficiency.
- VCU Hardware
Current powertrain controllers typically use high-performance microcontrollers, such as Cygnal’s C8051F020, Intel’s 80C196, TI’s
TMS320LF2407, and Freescale’s MC68376 series. Additionally, processors supporting Simulink automatic code generation include Freescale’s HC12,
MPC555, Infineon’s C166, and TI’s DSP C2000 and C6000 series.
These controllers are characterized by high speed, precision, and large memory capacity, meeting the demands of real-time control algorithms and offering extensive interfaces to support distributed and centralized control. Some of these controllers have been widely used in traditional vehicle control systems, with proven reliability. Among them, the
MPC555 processor, with its 40MHz operating frequency and 64-bit floating-point computation capabilities, large memory capacity, and rich peripheral interfaces, is an ideal embedded hardware platform for VCU control.
- VCU Development
In traditional control unit development, a serial development model is often used, including functional definition, hardware design, code writing, software and hardware integration, and system testing and calibration. Nowadays, the V-model development process is more commonly adopted. With technological advancements, Germany’s DSPACE company has provided real-time system simulation tools based on PowerPC and MATLAB/Simulink, supporting parallel development.
Step 1. Function Definition and Offline Simulation:
Define the controller’s functions and use MATLAB to establish a control system simulation model for verification.
Step 2. Rapid Controller Prototyping and Hardware Development:
Extract the controller model from the simulation model, establish physical connections through DSPACE physical interface modules, generate executable programs for online debugging, and simultaneously complete hardware design.
Step 3. Target Code Generation:
Use TargetLink to generate target code and write the underlying driver software for the target, then download the generated target code to the ECU.
Step 4. Hardware-in-the-Loop Simulation:
Verify the electronic control unit’s functions using real or simulated controlled objects for testing.
Step 5. Debugging and Calibration:
Connect the system, validated through hardware-in-the-loop simulation, to real controlled objects for actual operation tests and debugging.
