Workpiece Orientation Correction with a Robot Arm Using Visual Information

I f r o b o t s had the c a p a b i l i t y o f s u p p l y i n g ma­ c h i n e s w i t h w o r k p i e c e s w h i c h a r e n o t p r e o r i e n t e d , t h e r e w o u l d b e a s u b s t a n t i a l i n c r e a s e i n t h e num­ b e r o f r o b o t s used i n i n d u s t r y . A s i g n i f i c a n t c o n t r i b u t i o n to t h i s deve lopmen t w o u l d be a method w h i c h y i e l d s a t r a j e c t o r y whereby such a r o b o t h e l d w o r k p i e c e can b e t r a n s p o r t e d f r o m i t s r e c e p ­ t a c l e t o a mach ine f i x t u r e w i t h o u t a c o l l i s i o n . A n a l g o r i t h m i s d e s c r i b e d t o f i n d such a t r a j e c ­ t o r y . T h i s a l g o r i t h m employs r e f i n e m e n t o f a n i n ­ i t i a l e s t i m a t e o f the p o s i t i o n and o r i e n t a t i o n o f a r o b o t h e l d w o r k p i e c e . The r e f i n e m e n t p r o c e d u r e uses v i s u a l i n f o r m a t i o n . W i t h the r e f i n e d e s t i ­ mate o f the h a n d t o w o r k p i e c e t r a n s f o r m a t i o n , t he w o r k p i e c e can be moved t h r o u g h a s a f e t r a j e c t o r y , w h i c h was e s t a b l i s h e d d u r i n g a p r i o r i n s t r u c t i o n p h a s e .