Robust control of active trailer steering systems for long combination vehicles
Compared with Articulated Heavy Vehicles (AHVs) the tractor/semitrailer configuration, Long Combination Vehicles (LCVs) can significantly improve fuel economy, reduce green-house emissions, and decrease traffic congestion. However, LCVs face stability challenges at high speeds and exhibit inferior maneuverability at low speeds. Active Trailer Steering (ATS) has been explored to overcome these challenges. Most of the research conducted on ATS has been focused on using Linear Quadratic Regulator (LQR) technique. Although the LQR technique exhibits satisfactory results, it cannot alone effectively control the system in presence of disturbances, e.g. sensor noise, parametric uncertainties and un-modelled dynamics. Thus, it is crucial to design a control strategy, which is both robust and adaptable. To improve the robustness of the existing LQR controller, a Kalman Filter (KF) is added as a state estimator. KF aids LQR in predicting states in the presence of the disturbances. Another robust technique, µ synthesis is investigated. This paper aims at comparing different control strategies used for implementing ATS for LCVs.