Integrated Control Of The Vehicle Chassis Based On Function Allocation

The chassis is one of the most important components of vehicles. The performance of the chassis related to the ride, stability and safety performance of the vehicles directly. The physical construction of the vehicle chassis is at a degree perfect nowadays. The improvement of the chassis’performance depends on the electric control subsystems greatly. While the attendance of abounding electric control subsystems brings up new problems, such as imformation fusion, the subsystem coordinating and so on. So it is one of the research areas to avoid the conflicts between the subsystems.The chassis has many functions such as shock-absorbing, force transmiting, stability keeping and so on. While the needs of functions are different from situation to situation. So the function re-allocation during driving is considered to enhance the performance. The function allocation method is used in the integrated control of vehicle chassis to discover a new approach for subsystem coordinating. Based on Steer By Wire, Electric Stability Program(differential braking mode), Active Suspension System and Anti-lock Braking System, the followed jobs were done.1. Summarizing the existing studies, the steering, braking and suspension systems were modeled. The tire mechanics characteristics were analysed and a14DOFs vehicle model was estabilished. The scattered results were collected for a convenient study on the chassis dynamic.2. For integrated control of Steer By Wire system and Direct Yaw-moment Control system, a multi-loop control structure was estabilished. The stability control of vehicle plane motion was studied based on tires force distribution. Proposed a estimate method of the maximum yaw moment when the road friction coefficient was a constant. The integrated control of Steer By Wire system and difference braking system was approached by a dynamic force distribution.3. Studied the function allocation method of active suspension system considering the different function need under different situations. Based on the fuzzy logical and H∞theory, a function allocation controller that matched different condition was designed, which compromise the ride performance and stability performance.4. Focusd on the probable conflicts between electric stability program and anti-lock braking system. Study the integrated control approach of the two systems. Proposed a differential braking mode that was different from the traditional one, which avoided the conflicts.