Adaptive Event-Triggered Safety Control for String Stability of Vehicular Networked Systems

The safety platoon performance could be significantly enhanced by exchanging vehicle's information over the inter-vehicle communication (IVC). However, a preceding vehicle's jerk could seriously compromise platoon's stability under the limited bandwidth. This paper focuses on the safety platoon control to overcome the above problem. Firstly, a distributed adaptive event-triggered control (ETC) is proposed to adjust the transmission frequency by adaptively tuning the event-triggered threshold according to the preceding vehicle's jerk, which could be a tradeoff between improving transmission efficiency and reducing bandwidth occupation. Under such communication mechanism, a control scheme is proposed to obtain the safety platoon performance by adaptively tuning the cost function. Then, some sufficient conditions of the strictly $\mathcal {L}_{2}$ string stability and controller design method are provided under the distributed adaptive ETC and the safety control scheme. Further, an optimization algorithm for the controller gains is proposed to reduce on-line computation and improve the control performance by introducing an additional degree of design freedom into control input. Finally, a numerical example is used to verify the effectiveness and advantages of the proposed methods.