Robot Planning System Based on Problem Solvers

T h i s paper i s concerned w i t h a p l a n n i n g system f o r a r o b o t w i t h a hand and an eye w h i c h can m a n i p u l a t e b l o c k s . Two d i f f e r e n t k i n d s o f p r o b l e m s o l v e r s a r e used . One i s m a i n l y composed of a theorem p r o v e r based on t h e r e s o l u t i o n p r i n c i p l e , and the o t h e r c o n s i s t s o f a theorem p r o v e r based on p a t t e r n m a t c h i n g . These p rob lem s o l v e r s a r e c a l l e d GOAL-FINDER and JOB-SCHEDULER c o r r e s p o n d i n g to t h e i r f u n c t i o n s . GOAL-FINDER d e c i d e s a g o a l s t a t e t h a t i s s u i t a b l e f o r a n o r d e r o f a n o p e r a t o r . JOB-SCHEDULER produces a j o b sequence f o r a r o b o t t o p e r f o r m t h e g o a l s t a t e g i v e n t h e c o n s t r a i n t s o f t he b l o c k w o r l d . D e s c r i p t i o n terms r o b o t p l a n n i n g , p rob lem s o l v i n g , theorem p r o v i n g and d a t a s t r u c t u r e . 1 . I n t r o d u c t i o n Papers ' ' ' have been p r e s e n t e d h i t h e r t o c o n c e r n i n g r o b o t p l a n n i n g systems t h a t u n d e r s t a n d i n s t r u c t i o n s f r om a n o p e r a t o r and wh ich make p l a n s f o r a t t a i n i n g g o a l s . Th i s paper d e s c r i b e s a r o b o t p l a n n i n g system d e v e l o p e d f o r use i n a r o b o t . T h i s sys tem is concerned w i t h a r o b o t w i t h a hand and an eye w h i c h m a n i p u l a t e s b u i l d i n g b l o c k s i n response t o t h e o r d e r s o f a n o p e r a t o r . Two d i f f e r e n t k i n d s o f theorem p r o v e r s a re used t o d e m o n s t r a t e t h e e f f e c t i v e n e s s o f t h i s p l a n n i n g s y s t e m . One i s based on t h e r e s o l u t i o n p r i n c i p l e , t h e o t h e r o n p a t t e r n m a t c h i n g . The f o r m e r i s used in a p rob lem s o l v e r wh i ch u n d e r s t a n d s t he mean ing o f a s t a t e m e n t and w h i c h d e c i d e s a goa l s t a t e c o r r e s p o n d i n g t o t h e s t a t e m e n t . The l a t t e r i s a p p l i e d to a p rob lem s o l v e r wh i ch e f f e c t s a c o n c r e t e j o b sequence t o r e a l i z e t h e g o a l s t a t e d e s c r i b e d above . These p rob lem s o l v e r s a re c a l l e d GOAL-FINDER and JOB-SCHEDULER r e s p e c t i v e l y . The reason why two theorem p r o v e r s a r e used i n a r o b o t p l a n n i n g system i s t h a t i t i s n o t n e c e s s a r i l y p r o f i t a b l e t o p rocess two o p e r a t i o n s , f o r example t h a t o f r e p r e s e n t i n g a s t a t e and o f o b t a i n i n g a j o b sequence, w i t h o n l y one m e t h o d . A f u r t h e r f e a t u r e o f t h i s p l a n n i n g system i s t h a t t he p r o c e d u r a l d a t a s t r u c t u r e i s used f o r i n c r e a s i n g e f f i c i e n c y i n p rob lem s o l v i n g p r o c e s s e s . A n o u t l i n e o f t h e r o b o t p l a n n i n g s y s t e m , d e s c r i p t i o n s o f each o f t h e p rob lem s o l v e r s and f u t u r e c o n s i d e r a t i o n s a r e g i v e n i n t h e f o l l o w i n g c h a p t e r s . The p r o b l e m s o l v e r s and t he r o b o t p l a n n i n g sys tem d i s c u s s e d i n t h i s paper wou ld u n d o u b t e d l y b e a p p l i c a b l e i n many f i e l d s . 2 . The o u t l i n e s o f t h e r o b o t p l a n n i n g sys tem The f o l l o w i n g p r o b l e m i s p r e s e n t e d as an example o f t h e w o r k i n g o f a r o b o t p l a n n i n g s y s t e m . There a r e many b l o c k s , o f v a r i o u s shapes and c o l o u r s , and w o r k i n g desks upon w h i c h a r o b o t m a n i p u l a t e s t h e b l o c k s . The r o b o t i s made to b u i l d s t r u c t u r e s , such as a t o w e r , a house , a b r i d g e , e t c . , i n response t o t a s k i n s t r u c t i o n g i v e n b y a n o p e r a t o r t o t he r o b o t i n a r e s t i c t e d fo rm a s f o l l o w s ;