String exponential stability analysis and control of vehicular platoons with bounded unknown parameters and time delays

String stability is essential for platoons. In this article, sufficient conditions for the string exponential stability of a class of longitudinal following platoon systems with time delays are investigated. Based on the constant spacing policy, a sliding mode control strategy is proposed for the look-ahead platoon with bounded unknown parameters and time delays to ensure the string exponential stability of the platoon. Numerical simulation findings including position, speed, acceleration errors, and inter-space between adjacent vehicles can verify the efficiency and feasibility of the proposed control systems. In simulations, the platoon with certain parameters and no time delays should be compared with the case with bounded unknown parameters and time delays.