Modeling, simulation, and active control of tractor-semitrailer combinations

Thesis Type: Postgraduate

Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Graduate School of Natural and Applied Sciences, Graduate School of Natural and Applied Sciences, Turkey

Approval Date: 2015




Articulated heavy vehicles (AHVs) are among the most common means of road transportation. They present, however, some specific performance limitations and safety risks due to their rather special dynamic characteristics. AHVs have maneuverability problems at low speeds as manifested by their Path Following Off-Tracking (PFOT). Further, AHVs are most likely to lose their stability at high speeds in three basic manners: trailer swing, jackknifing, and roll over which are the most common causes of many severe accidents. Such undesired behavior make the AHVs less stable and more dangerous vehicles compared to single unit vehicles. In this study, the potential of Active Steering Control (ASC) of the semitrailer in improvement of the maneuverability and stability of tractor-semitrailer combinations is investigated. Existing AHV dynamic handling simulation models in the literature are studied and a model suitable for the aims of this study is presented in detail and implemented in the simulation environment (MATLAB). The vehicle handling model is then validated using a commercial software. The controller for the ASC is determined through the use of the Linear Quadratic Regulator (LQR) optimal state-feedback control which aims to minimize the low-speed PFOT as well as the high-speed roll motion and the Rearward Amplification (RA) of the semitrailer’s lateral acceleration. The weighting factor selection for the control system is performed by means of Quantum Particle Swarm Optimization (QPSO) technique. Basic ASC along with two additional strategies are applied to the vehicle model and the results are compared to the baseline vehicle without ASC. The results from simulations show that the combination with ASC exhibits desirable improvements compared to the baseline vehicle.