Distributed prescribed performance platoon control for heterogeneous vehicles with quadratic spacing policy based on ESO

This paper focuses on the distributed cooperative prescribed performance tracking control issue of heterogeneous vehicular platoon. For longitudinal control of the vehicle model, due to the fact that the vehicle platoon cannot fully achieve zero initial spacing errors (ISEs) in the initial state of stationary or motion, non-zero ISEs may make the model impossible to assure internal stability or string stability. To resolve this difficulty, an improved quadratic spacing policy is constructed by employing a design variable, where non-zero ISEs can be allowed for third-order vehicle platoon system. In particular, the singular problem of controller is processed by using the hyperbolic tangent function. Subsequently, a modified finite-time performance function is proposed, which guarantees that the spacing errors can converge to the arbitrary small symmetrical region within finite time, and the convergence rate has significant advance. Then, the total dynamic estimated terms are approximated by establishing an extended state observer. Eventually, the simulation is carried out to verify the effectiveness of the proposed results.