Obstacle avoidance using an octree in the configuration space of a manipulator

An automat ic system for p lanning safe t r a j e c t o r i e s f o r a computer c o n t r o l l e d manipulator among obs tac les i s a key component o f r o b o t assembly operations. This paper describes an a lgor i thm t rans forming C a r t e s i a n o b s t a c l e s i n t o o b s t a c l e s i n t h e space o f t h e f i r s t t h r e e j o i n t s o f a man ipu la to r w i th s i x r e v o l u t e j o i n t s (e.g. a ACMA-CRIBIER V80), and g i v i n g a h i e r a r c h i c a l d e s c r i p t i o n o f t h e f r e e space by mean o f an oct ree. Such a d e s c r i p t i o n i s v e r y u s e f u l i n t e s t i n g f o r c o l l i s i o n between the arm o f t he man ipu la to r and obs tac les s ince it i s represented by a p o i n t i n t h i s space.