A systematic antiwindup strategy and the longitudinal control of a platoon of vehicles with control saturations

Current methodologies for designing control systems usually ignore the effects of control saturations. For vehicle platooning, this can be especially disastrous since the performance of a platoon of nonidentical vehicles is, in general, severely limited by saturating control signals. This paper presents a systematic design procedure for adapting a nominal controller, designed without regard to control saturation, to a higher performance nonlinear controller that explicitly accounts for the saturating nonlinearities while preserving stability. In particular, the error governor (EG) scheme proposed by P. Kapasouris et al. (1988) is extended and applied to the IVHS problem found by S. Sheikholeslam (1990). This extension is a less conservative strategy that explicitly accounts for an important class of controller designs, including proportional control and a class of nonlinear feedback designs. Results of the study demonstrate that severe windup found in nominal platooning applications can systematically be eliminated without loss of steady-state performance. This significantly increases the range of maneuvers open to the lead vehicle, thus enhancing the utility of a proposed design. An extensive simulation of a 15-car platoon of nonidentical vehicles with nonlinear vehicle models illustrates these results.