Research And Design Of The PCV EPS Controller

Electronic Power-assisted System is a specialized agency for assisting the driver tochange or keep the car running direction. It has broad prospects for development as ahigh-tech modern automobile development in the field of future automotive powersteering. The rapid development of automobile bus technology,put forward higherrequirements for the EPS control system, which is to support the CAN bus protocol,linkage and information sharing vehicle body control to improve performance andboost traffic safety systems. Therefore, the development of PVC support EPS controlsystem based on CAN bus has important practical significance.This thesis analyzes development status and trends of EPS and CAN bustechnology, introduced the principle of EPS system.It has selected a PVC models toanalyze the power characteristics required in accordance with its dynamics, get theassist characteristic curve and its associated parameters. In addition, it has a detailedanalysis of the formation of the control strategy used by the system to work and CANcommunication network. On this basis, we developed the power steering systems forPVC based on the CAN bus to Freescale16-bit microcontroller core MC9S12G128.In hardware design, we designed of the hardware control circuit withmicrocontroller, and formatted the core control node network of CAN bus protocol,which is particularly important for circuit design includes a power supply circuit, thesignal acquisition circuit node, the motor drive circuit, fault detection circuit andCAN bus circuit. We have considered the stability of the system focuses on theperformance of the system power and hardware design is optimized to improve thestability of the system work.In software design, the control program was designed by using of hierarchical, it isalso include the CAN-bus network, EPS power control system software design, aswell as for data acquisition and signal processing for each node in the software design,proposed an incremental digital PID closed-loop control software. In addition, it alsodesigned for when the system fails, fault detection and handling procedures to ensurethat the system is safe and reliable.Finally, through the EPS controller CANoe in the loop simulation testing andhardware in the loop test, the results showed that: in the whole system, critical information can be shared, such as vehicle speed, engine speed, the controller status,and has a certain timeliness; For power steering system characteristics, the parametersare in line with the design requirements.