DYNAMIC COLLISION-AVOIDANCE AND CONSTRAINT VIOLATION COMPENSATION

This paper uses concepts in multibody dynamics, together with a collis ion detection algorithm to study the dynamics of collision avoidance. Obstacle avoidance of a mechanical system in motion is expressed in te rms of distances, relative velocities and relative accelerations betwe en potentially colliding bodies. The generalized control forces (const raint forces) used to adjust the system dynamics are based on an n-tim estep collision avoidance algorithm. Constraint violations resulting f rom sudden changes in motion direction are compensated for by feeding back the errors of position and velocity constraints to assure asympto tic stability. The procedures developed are illustrated through a mane uver in space of a robotic manipulator used for grasp and deployment.