Immediate transitions for an automated bus using magnetic and DGPS sensing systems

This paper describes the transition control in an integrated automated bus system for Bus Rapid Transit. Employing two lateral sensing technologies, magnet markers and DGPS/INS systems for enhanced reliability and extended operating range, this integrated automatic system involves both the manual-automatic transition and the transition between the magnet-based control and the DGPS/INS-based control. This paper proposes a unified transition method, in which an open-loop dynamic initial conditioning is added to the existing high-gain closed-loop automatic steering control systems to provide suitable references to the high-gain automatic steering controllers. Designed as a lower-gain (softer) regulation controller, this open-loop dynamic initial conditioning smoothly drives the lateral and heading angle errors to zero during transitions. Experimental results with a 40ft bus demonstrate that the proposed method achieves smooth and immediate transitions between manual and automatic control as well as between the two control systems.