Research on Optimal Feedback Tracking Control of TCS Slip Ratio of High Speed Vehicle in Complex Road Conditions

For the purpose of investigating control strategy of making high speed vehicle drive steadily in complex road conditions, affine nonlinear dynamic model of TCS slip ratio is built. Then, comprehensive optimization of slip ratio error with its change rate is taken as control objective, and analytical solutions of optimal slip ratio and traction control torque are derived through minimum principle. And then, real time cooperative computation of traction torque without any adhesion coefficient information of complex road conditions can be accomplished by utilizing analytical solution of optimal slip ratio with feedback signals such as traction acceleration, vehicle speed and angular velocity of tire. Effectiveness of proposed optimal control for tracing different target slip ratios in different complex road conditions is investigated through MATLAB/Simulink numerical evaluation. It can be concluded that feedback slip ratio synchronizes with target slip ratio at any specified time, and also slip ratio error is determined by its initial value and ratio between weight of slip ratio error and that of its change rate in control objective functional. Besides, inevitable chattering of feedback slip ratio along sliding mode surface occurred in sliding mode control processes for slip ratio tracking is prohibited. Consequently, the proposed optimal feedback tracking control strategy is valid and convenient in engineering applications.