Dynamic window based approach to mobile robot motion control in the presence of moving obstacles

This paper presents a motion control method for mobile robots in partially unknown environments populated with moving obstacles. The proposed method is based on the integration of focused D* search algorithm and dynamic window local obstacle avoidance algorithm with some adaptations that provide efficient avoidance of moving obstacles. The moving obstacles are modelled as moving cells in the occupancy grid map and their motion is predicted by applying a procedure similar to the dynamic window approach. The collision points of the robot predicted trajectory and moving cells predicted trajectories form the new active obstacles in the environment, which should be avoided. The algorithms are implemented and verified using a Pioneer 3DX mobile robot equipped with laser range finder.

I. Introduction

A mobile robot should perform goal-directed tasks in dynamic and unknown environments. Both global path planning and local reactive obstacle avoidance algorithms must be implemented and integrated in a single motion control module in order to provide the robot with this capability. While a global path planning algorithm calculates optimal path to a specified goal, a reactive local obstacle avoidance module ensures tracking of the global path and takes into account the unknown and changing characteristics of the environment based on the local sensory information.