Co-simulation On Steer-by-Wire Integrated Control Based On ADAMS And MATLAB

Automobile electronic is considered a revolution in the process of the evolution of auto technology. Automobile electronic degree is regard as the important symbol of measuring modern automobile level, and is the most important technical measures of improving performance of automobile. Automobile's steer-by-wire is a new type of steering system, a period of mechanical connection is cancelled between the steering wheel and the car front tires, insteading of the electronic control unit to complete to task. The steering wheel angle signal is transmitted to controller by electrical signals, the controller received all sensor signals and calculated by intelligent control algorithm, then get corresponding front wheel corner or steering torque to drive motor rotation. This structure makes cars realize safety stable steering without mechanical connection in the state.Based on reviews steer by wire system of automobile development and current basis, first the key technology of steer by wire system-FlexRay on-board network is analyzed, and FlexRay on-board network operation mechanism and application in automobile now are introduced in this thesis. In this thesis, the on-board network system structure of basing on FlexRay network is putted forward and further analyzed the gateway of the on-board network.Based on the motion characteristics, use intellective control technical to solve two key part of the steer by wire—the design of control front wheel corner and feedback torque. Through designing double closed loop series connection fuzzy control system of yaw angle speed and front wheel angle, cars can turn with the best front wheel corner in different speeds and in different angular velocity, meanwhile in turn car can quickly return to stable state, and improve the system stability handling. And according to the traditional characteristics of car self-aligning torque, different expressions of car self-aligning torque in different speed are designed.Front wheel control system and self-aligning torque are designed in MATLAB; a car model with steer by wire system is built using the ADAMS software; Through MATLAB and ADAMS software interface setting and jointing simulation, virtual prototype is formed. According to car's performance index, virtual prototype is simulated of the various car states; validate the correctness of design of front wheel corner control system.In the finish, effect of roll angle in the stability of car is analyzed, according to three degrees of freedom model; front wheel steering fuzzy integrated control system was designed based on effect of roll angle. Introducing the adjustable factor, front wheel fuzzy rules implementing online adjustment according to roll angle error, and it can avoid that car overturned because excessive roll angle. Simulation shows compensation feedbacks of the roll angle have certain improving auto stability role.