Unified lateral motion control of vehicles for intelligent vehicle highway systems and visual guidance

This dissertation deals with the lateral guidance of vehicles in Intelligent Vehicle Highway Systems (IVHS) with the main emphasis on lane change maneuvers. The other aspects of the lateral guidance are lane following maneuvers. In the IVHS branch conducted at the California PATH, the lateral position of the vehicle is measured using the magnetic road reference system, which consists of magnetometers installed in the vehicle and magnets embedded in the highway. In addition, a yaw rate sensor and an accelerometer are installed on the vehicles.; Two approaches are studied for the lane change maneuvers in IVHS; one is to treat the maneuvers as a tracking control problem, and the other is to use the unified lateral guidance algorithm proposed in this dissertation. In the tracking control approach, the desired trajectory for the lane change maneuvers, called the virtual desired trajectory (VDT), is designed considering lateral acceleration and lateral jerk for passengers' ride comfort. A sliding mode controller is used as the tracking controller. To enhance passengers' ride comfort, the sliding surface is constructed with respect to the filtered tracking error, which results in smoother control action than the standard sliding mode controller. A reduced order Kalman filter is designed to provide estimates of the state variables of the vehicle, which are required to implement the sliding mode controller. This approach is validated by experiments performed on a full size vehicle.; The unified lateral guidance algorithm consists of a desired yaw rate generator and a yaw rate tracking controller. The desired yaw rate generator provides the yaw rate tracking controller with the yaw rate to achieve the two maneuvers, either lane change maneuvers or lane following maneuvers. Therefore, the same control algorithm can be applied to the two types of maneuvers. The desired yaw rate for lane following maneuvers is set to make the lateral position measurement from the magnetic road reference system converge to zero. The desired yaw rate for lane change maneuvers is obtained from VDT. The unified lateral guidance algorithm also includes a mode switching algorithm for smooth transitions from the lane change maneuvers to the lane following maneuvers. Simulation results support the effectiveness of this approach.; The unified lateral guidance is also applied to visual guidance of a vehicle. Here, the desired yaw rate for lane following maneuvers is obtained from the kinematic analysis of the lateral offsets at the two look-ahead positions in the image. The proposed algorithm is validated by simulations.