A unifying discrete event framework for mobile robots

A new, complete discrete event framework for modelling and control of mobile robots is presented. Discrete event modelling is the natural paradigm for systems where motion is constrained by the presence of obstacles. As the mobile robot encounters obstacles the system dynamics change dramatically. These changes are explicitly represented by discrete events. The discrete event framework supports the use of existing path planning techniques as well as reactive approaches and considers the dynamics of the robot. A number of discrete event models for mobile robots have been proposed but these use rather arbitrary definitions for the discrete states. Instead, we rigorously define the discrete state from the currently active constraints upon the robot. Experimental results demonstrating the application of the discrete event model for path planning and control of a nonholonomic mobile robot in indoor office navigation tasks are presented.