Controlling tractor-semitrailer vehicles in automated highway systems: Adaptive robust and Lyapunov minimax approach

Abstract

In this paper, we design a coordinated steering and braking control scheme to ensure the tractor-semitrailer vehicle system is practically stable. The tractor's steering input is designed to realize lane tracking and the semitrailer's differential braking torque is designed to improve the stability of the semitrailer. This control methodology is developed in two steps. Firstly, the expected steering input and the expected differential braking force are derived by introducing a set of given tracking constraints and considering the possible initial condition derivation from the constraints based on the Udwadia-Kalaba approach. Secondly, we develop an adaptive robust control law to tackle the parameter uncertainty, which may be (possibly) time-varying, and design the required braking torques, which are the actual inputs, to generate the desired braking forces. Furthermore, this control methodology can deal with nonlinear mechanical systems with both holonomic constraints and nonholonomic constraints. Numerical simulations demonstrate that the control algorithm could guarantee the vehicle dynamics are practically stable and achieve lane following maneuvering.