Steering control of automated vehicles using absolute positioning GPS and magnetic markers

These days, automated vehicle control technology has become one of the most promising approaches to provide significant benefits to the transportation system in terms of traffic safety and efficiency. In this dissertation, steering control for passenger cars on automated highways is analyzed. Feasibility of an automatic steering system based on an absolute positioning global positioning system (GPS) and a magnetic marker reference system has been evaluated using computer simulations. Its performance during emergency situations is considered, as it is a vital safety issue in highway automation. State estimation and control algorithm issues are examined for a simplified linear vehicle model as well as for a complex nonlinear vehicle model. By using GPS and a magnetic marker sensor, an accurate and real-time estimation of the vehicle's lateral displacements with respect to the road can be accomplished. A robust control technique in the form of a parameter space approach in an invariance plane is utilized for lateral controller design based on a higher order nonlinear vehicle model. In addition, the control system incorporates an algorithm based on road curvature preview for ride comfort enhancement. The proposed estimation and control system is shown, in computer simulations, to be effective in handling vehicles under normal and emergency situations.