Nonlinear yaw dynamics analysis and control for the tractor-semitrailer vehicle

This study mainly focuses on the lateral dynamics, stability and the control problems of a typical tractor-semitrailer vehicle in critical situations. First, the lateral dynamics and stability are analysed by nonlinear dynamics theories involving equilibrium, stability and bifurcation, based on a nonlinear vehicle model whose physical parameters can vary with the actual load conditions during transportation. The lateral instability forms of jackknife, trailer swing and trailer oscillation reported in literature are analysed and discussed based on nonlinear dynamics analysis and then suggestions for the stability controller design are also proposed. As another main work of this study, the stability control of the tractor semi-trailer vehicle based on Sliding Model Control (SMC) method is discussed and especially the design of the sliding surface to improve the control performance and robustness against the variation of load conditions is analysed in detail. The effectiveness of the proposed control scheme is evaluated by numerical simulations based on a full nonlinear vehicle model constructed in Appendix 1. Some important and valuable suggestions have been proposed for the stability control of the tractor-semitrailer vehicle on the basis of this work.