Nonlinear controller design for automated vehicle applications

This paper discusses the development of a nonlinear controller design methodology and its application to the automated longitudinal control of automotive vehicles. The method is called the multiple sliding surface method and is closely related to sliding mode control, input/output linearization and integrator backstepping. The method was developed for a class of systems, typical of automotive control systems, where the uncertainties are mismatched and where many of the equations contain sparse, experimentally obtained maps. The error bounds on these maps are often unknown and their sparseness makes them difficult to differentiate. The developed method does not require any derivatives and has guaranteed semi-global stability. This paper summarizes the development of the method and applies it to design a combined brake/throttle controller for precision vehicle following. This controller was implemented on the California PATH vehicles in DEMO'97, an automated highway technology demonstration that occurred in San Diego, California in August of 1997. Some experimental data that shows the performance of the longitudinal controller will be presented in this paper.