A Design Approach to Optimal Cruising Control with String Stability Constraint for Vehicle Platoon

Cruising control is a fundamental issue for the vehicle platoon and the string stability, which guarantees smooth motion of the platoon by rejecting the car-tracking error propagation along the platoon, is a key specification of the control design. This paper proposes a design approach to realize cruising control by solving an optimal control problem with the cost function under the string stability constraint. This control scheme intends to optimize the car-tracking error in terms of not only ego vehicle but also the spacing error of the neighbor vehicle. On the other hand, in order to improve the ride comfortability, constraints to the desired acceleration are also involved in the proposed control problem. Finally, the desired acceleration of each vehicle in the platoon is obtained by solving the optimal control problem, and the solution is a feedback control law of speeds of the ego vehicle and the corresponding proceeding vehicle. Numerical simulation examples are presented, and the results validate the effectiveness of the cruising control system.