This chapter presents a new reactive navigation algorithm for a wheeled mobile robot (WMR) with a differential drive mechanism moving in unknown environments [1]. The mobile robot is controlled to travel to a predefined goal position safely and efficiently without any prior map of the environment. The navigation is achieved by modulating the steering angle and turning radius. To avoid obstacles while seeking the goal position, the dimensions and shape of the robot are incorporated to determine the set of all possible collision-free steering angles. The algorithm then selects the optimum steering angle candidate to contour the obstacle. Simulation and experimental results on a WMR prototype are used to validate the proposed algorithms
