OBSTACLE AVOIDANCE IN A DYNAMIC ENVIRONMENT - A COLLISION CONE APPROACH

A novel collision cone approach is proposed as an aid to collision det ection and avoidance between irregularly shaped moving objects with un known trajectories. It is shown that the collision cone can be effecti vely used to determine whether collision between a robot and an obstac le (both moving in a dynamic environment) is imminent. No restrictions are placed on the shapes of either the robot or the obstacle, i.e., t hey can both be of any arbitrary shape. The collision cone concept is developed in a phased manner starting from existing analytical results -available in aerospace literature-that enable prediction of collision between two moving point objects. These results are extended to predi ct collision between a point and a circular object, between a point an d an irregularly shaped object, between two circular objects, and fina lly between two irregularly shaped objects. Using the collision cone a pproach, several strategies that the robot can follow in order to avoi d collision, are presented. A discussion on how the shapes of the robo t and obstacles can be approximated in order to reduce computational b urden is also presented. A number of examples are given to illustrate both collision prediction and avoidance strategies of the robot.