Software Development ESP System Test Platform For Passenger Car

The safety performance of vehicle, especially the active safety performance, gets more and more attention of consumers. It has been in research focus for every automobile corporation. Being the representative technology, control system of Electronic Stability Program can enhance the safety performance remarkably. It has a very important significance that we should start the research on the ESP system to break the technical monopoly.Based on the domestic and abroad achievements in the field, the dissertation pays more attention to the following issues: the history and the present of the ESP system; proposing four stages during the development for ESP system and designing platform for every stage; demonstrating the most important software part -control algorithm and strategy for ESP system; establishing the dynamics off-line simulation platform; vehicle test on road; the plan of hardware-in-loop platform. The conclusions are as follows:The ESP system is consist of the ECU, the Hydraulic modulator, sensors(yaw sensor, lateral-acceleration sensor, steering-wheel sensor, wheel-speed sensor, primer pump pressure sensor) and the conventional brake system. When a vehicle is cornering at an excessive speed, the lateral forces on all four wheels determine the lateral acceleration and yaw moment, the tire side forces may easily reach the grip limit which may cause the vehicle lose stability. The ESP system can analysis the data feedback by the sensors , and then prevent the vehicle from understeering or oversteering by controlling the brake force or traction force. The development for ESP system is divided into four stages. The first stage is to built off-line simulation platform. Then a hardware-in-loop test platform must be built. The last platform is road test platform. Based on the dSPACE Rapid Control Prototyping system, four technical plans are proposed which can demonstrate the research direction.The control strategy and algorithm for the ESP system are researched deeply i. The stability of vehicle is detailed analyzed. Generally, the yaw rate and slip angle are chosen as control parameter of the ESP system. And the nominal yaw rate and nominal slip angle can be calculated by the linear bicycle model. But in the practical application, there is a bigger error in calculating the slip angle. So we proposes that the slip angle rate should be the control parameter. Yaw rate error PD control and slip angle rate error P control are applied to yaw moment control. By yaw moment distributing logic, the best braking wheel is chosen and the target pressure is confirmed. During distributing the pressure, the pressure which is determined by the slip rate control must be considered to prevent the lock brake.This pressure can be calculated by slip rate error P control.dynamics simulation software is built to validate the ESP control strategy and algorithm. A vehicle model can describe the vehicle non-linear characteristics under limit condition is needed for simulating vehicle stability control system. The vehicle dynamic models are established, which comprise several key parts of vehicle, such as engine,driver,tyre,brake,and a 7-DOF whole vehicle model etc. Using the vehicle model, the control algorithm is carried on by off-line simulation. A simulation study is made on driver step input, single cyclical sine input and multi-cyclical sine input and double lane change. The correctness and practicability of ESP control system are validated and sets the foundation for further research through off-line simulation and analysis.Through the road test research of the ESP system, that is the high-μdouble lane change test and the low-μdouble lane change test The correctness and practicability of ESP control system are validated. The finally result proves that the control strategy and algorithm for the ESP system are on effect especially on the low-μroad.