Abstract
In this article, a vehicle dynamics integrated control algorithm using an on-line nonlinear optimization method is proposed for 4-wheel distributed steering and 4-wheel distributed traction/braking systems. The proposed distribution algorithm calculates the magnitude and direction of tire forces that satisfy constraints corresponding to the target resultant force and moment of vehicle motion and also minimizes the maximum μ rate (= tire force / friction circle) of each tire. The convexity of this problem is shown, and so global optimality of the convergent solution of the recursive algorithm is guaranteed. This implies that the theoretical limited performance of vehicle dynamics integrated control is clarified. The proposed algorithm is based on SQP (Sequential Quadratic Programming) and the steepest gradient algorithm. Calculation performance of the proposed algorithm is compared that of the primal-dual interior-point method, which is a representative optimization method. Furthermore, the effect of this vehicle dynamics control is demonstrated by a simulation and experiment comparing various vehicle dynamics integrated control methods.
