am intermediate language for robot programming

8/6/2019 Am Intermediate Language for Robot Programming

1/9

Roboacs & Computer-Integrated Manu[acturmg,Vol 5, No 1, pp 11-19, 1989 0736-5845/ 8953 00 + 0 00Pnnte d m Gre at Bri tain Pergamon Press plc

P a p e r

V M L : A N I N T E R M E D I A T E L A N G U A G E F O R R O B O T P R O G R A M M I N G

P A O L O B I S O N , * E N R I C O P A G E L L O * t and G A E T A N O T R A I N I T O **LAD SEB, In s t it u t e o f CN R (Na t iona l Resea rch Counc i l o f It a ly ), Co r so S t a ti Un i t i 4, Padova 35020 , I t a ly

and t ln s t i tu te of Elec t r ica l and Elec t ronic Enginee r ing , Univers i ty of Padua , Via Gradenlg o 6 /a ,35100 Padov a , I t a ly

V M L ( Vi r tu a l M a c h i n e L a n g u a g e ) i s a n i n t e r m e d i a t e le v e l p r o g r a m m i n g l a n g u a g e fo r m a n i p u l a t o r s w h i c ha l l o w s s t r u c t u r e d p r o g r a m m i n g , c o n c u r r e n c y, b u i l t - i n r o b o t - s p e c i f ic d a t a t y p e s a n d a c e r t a i n d e g r e e o f r o b o ti n d e p e n d e n c e . V M L c a n b e u s e d b o t h a s a n i n t e r a c t iv e c o m m a n d l a n g u a g e a n d a s a t a r g et l a n g u a g e fo r a d v a n c e dh i g h - l e v e l r o b o t i c s s o f t w a r e s y s t e m s . I t s d e f i n i t i o n i n v o l v e s a n u m b e r o f d e s i g n c h o i c e s w h i c h p o r t r a y a n a b s t r a c tv i e w o f t h e r o b o t a s o n e o f s e v er a l c o m p o n e n t s i n t h e a u t o m a t e d f a c t o r y.

1. I N T R O D U C T I O NF l e x i b l e p r o g r a m m a b i l i t y g i v e s i n d u s t r ia l r o b o t st h e i r m a i n a d v a n t a g e o v e r t r ad i t io n a l a u t o m a t i o n .T h e d e v e l o p m e n t o f g o o d q u a l i ty s o f t w a r e s y s t e m s i st h e r e f o r e t h e k e y f a c t o r f o r r o b o t s y s t e m i n t e g r a t i o ni n to C I M . A t L A D S E B , a n In s t it u t e o f C N R i nP a d u a , w e h a v e i m p l e m e n t e d V M L ( Vi r tu a l M a c h i n eL a n g u a g e ) , a s t r u c t u r e d i n t e r m e d i a t e l e v e l l a n g u a g e

f o r m a n i p u l a t o r s , t o a c t b o t h a s a c o m m a n d l a n g u a g ef o r m e c h a n i c a l a s s e m b l y a n d a s a t a r g e t l a n g u a g e f o ra d v a n c e d h i gh l e v e l s o ft w a r e s y s t e m s fo r a u t o m a t e da s s e m b l y.

V M L i s a re a l - ti m e c o n c u r r e n t p r o g r a m m i n g l a n -g u a g e f o r a c t u a t o r a n d m o t o r c o n t r o l ; i t a l l o w s I / Oc o m m u n i c a t i o n b e t w e e n t h e m a n i p u l a t o r a n d t h eh u m a n o p e r a t o r a n d a l s o o f fe r s p r i m i t i v e s f o r d e f i n -i n g a n d h a n d l i n g v e c t o r s , r o t a t i o n s a n d f r a m e d a t at y p e s .

A p o r t a b l e i n t e r p r e t e r f o r V M L h a s b e e n w r i t t e ni n P a s c a l ; 1 i t h a s b e e n t e s t e d i n c o n t r o l l i n g b o t h t h e

S u p e r s i g m a R o b o t a t M i l a n P o l y t e c h n i c a n d t h eP u m a m a n i p u l a t o r s a t M i l a n P o l y t e c h n i c a n d t h eL A D S E B I n s ti t u te o f C N R . T h i s p a p e r d e sc r ib e s th ef ul l d e f i n i t io n o f V M L a n d g i v e s s o m e i m p l e -m e n t a t i o n d e t a i l s .

We b a s e d o u r f i rs t e x p e r i m e n t a l i m p l e m e n t a t i o n 1o n t h e d e s i g n p r i n c i p l e s o u t l i n e d i n a p r e v i o u s

p a p e r. I4 A c c o r d i n g t o t h e s e p r i n c i p l e s , a s o f t w a r es y s t e m fo r a u t o m a t e d m e c h a n i c a l a s s e m b l y s h o u ldc o n s i st o f a m u l t i l e v e l s o f t w a r e s t r u c t u r e d i s t r i b u t e do v e r a m u l t i p ro c e s s o r a r c h it e c tu r e . V M L h a s b e e nu s e d a s a s o f t w a r e c o m p o n e n t i n a s t r i c t l y h i e r -a r c h i c al h a r d w a r e s t r u c t u r e t o c o n t r o l t h e S u p e r -s i g m a R o b o t a t M i l a n P o l y t e c h n i c s ( se e F ig . 1 ),w h e r e i t h a s b e e n u s e d a s a n a l t e r n a t i v e t o t h e

p r e v i o u s M A L l a n g u ag e . 13 V M L h a s a ls o b e e n u s e da s t h e c o r e i n t e r p r e t e r c o n t r o l l i n g a P u m a ; 2 i n t h isa p p l i ca t i o n V M L is a b l e to c o m m u n i c a t e w i t h VA L ,t h e P u m a p r o g r a m m i n g l a n g u a g e ( s e e F ig . 2 ).

T h e I t a l i a n p a r t n e r s i n t h e E s p r i t R e s e a r c h P r o -j e c t N o . 6 2 3 ( O p e r a t i o n a l C o n t r o l o f R o b o t S y s t e mI n t e g r a t i o n i n t o C I M : S y s t e m P l a n n in g , I m p l i c i t a n dE x p l i c i t P r o g r a m m i n g 2 s) a r e c o n s i d e r i n g t h e p o s s i -b i l i ty o f u s in g V M L , o r a r e v i s e d v e r s i o n o f i t, a s t h eI t a l i a n n a t i o n a l t o o l f o r i n t e r fa c i n g w i t h t h e E x p l i c i tP r o g r a m m i n g S y s t e m ( w h i ch w il l b e d e v e l o p e d b yt h i s p r o j e c t ) .

A t p r e s e n t w e l o o k a t V M L a s a t o o l b e l o n g i n g t oa m o r e g e n e r a l d i s t r i b u t e d s o f t w a r e s y s t e m f o ra u t o m a t i c m e c h a n i c a l a s s e m b l y. S u c h a s y s t e m ,b a s e d o n a m e s s a g e - p a s s in g p r o g r a m m i n g e n v i r o n -m e n t , is u n d e r d e v e l o p m e n t a t L A D S E B o n a d i st ri -b u t e d h a r d w a r e s t r u c t u re . 2 I t u s e s V M L a s a t a r g e tr o b o t c o m m a n d l a ng u a ge .

Acknowledgements--This pro j ec t ha s been suppor t edby CNR and by t he M PI (Min i s try o f Pub l ic Educa t ion )th rough the "P roge t to d l R ice rca su l l e Me todo log l eEle t t ronlche , Informat lche e S is temis t iche in Robot ica" .The fo l lowing people have a lso cont r ibuted to the des ign

and imp lem en ta t i on o f VML: R . Cas s ln i s and G . G ln i o fMilan Poly technic , M. G lnl of the U nivers i ty of Minnesotaand seve ra l st uden t s o f the E .E . Dep t . o f Padua Un ive r-s it y, am ong whom we pa r t i cu l a r ly r em em ber G . Cheme l lo ,F. Ropela to , F. Rodlghiero and A. Tose t to .

11


2/9

12 Robo t i c s & Compute r- In t eg ra ted M anufac tu ring Vo lume 5 , Number 1 , 1989

i[nter'face

Fig. 1 . C ontrol sys tem for the O hvet t l Supers lgm a robot .

[ ~ Sensors

Puma 5 6 0 f ~ Macintosh

D - ~ VME

VAX 11/750

WarRsta on

Fig . 2 . Conf igu ra tion o f the LA DS EB Robo t i c s Labora to ry

I n b o t h t h e f i rs t c a s e ( m a s t e r - s l a v e a r c h i t e c t u r e )a n d t h e s e c o n d ( d i s t r i b u t e d a r c h i t e c t u r e ) , V M Lm u s t b e i n t e g r a t e d i n t o a m o r e g e n e r a l s t r u c t u r ew i t h w h i c h i t c o m m u n i c a t e s . I t i s p o s s i b l e h o w e v e rt o u ti l iz e V M L a s a s t a n d - a l o n e s o f t w a r e s y s t e m . W eh a v e p r o p o s e d a s m a l l g r a p h i c o p e r a t i n g e n v i r o n -m e n t w i t h a r e a l - t i m e s i n g l e - s t e p i n t e r p r e t a t i o nm o d e f o r e x e c u ti n g V M L p r o g r a m s i n t e r a c ti v e l y.

2 . D E S I G N I S S U E S F O R V M LI n t h e f o l l o w i n g , w e w i ll r e v i e w t h e d e s i g n c r i t e r i a

w h i c h le d t o V M L a s a n i n t e r m e d i a t e l e v el p o r ta b l ea n d m o d u l a r l a n g u a g e .

2 .1 . Ro bo t pro gra mm ing logical levelsR o b o t p r o g r a m m i n g h a s e v o l v e d c o n s id e r a b l y

s in c e th e e a r l y p r o g r a m m i n g l a n g u a g e s f o r r o b o t i c s .F i r s t o f a l l , m a n y e x i s t i n g r o b o t p r o g r a m m i n g l a n -g u a g e s a r e n o t a c c e p t e d b y t h e a v e r a g e u s e r a s t h eo n l y m e a n s o f in t e r a c t i o n w i t h t h e r o b o t . U n l e s s ap r o g r a m m i n g e n v i r o n m e n t a l r e a d y p r o v i d e s t h e

p r o g r a m m i n g l a n g u a g e , t h e u s e r t e n d s t o r e s t r i c th i m s e l f t o t e a c h - b y - s h o w i n g t e c h n i q u e s , t h e r e b yr e d u c i n g t h e r o l e t h e r o b o t l a n g u a g e t o j u s t t h a t o fo n e o f s e v e r a l p o w e r f u l i n t e r a c t iv e t o o l s .

I n a d d i t i o n , t h e r o b o t is p r o g r e s s i v e l y v i e w e d a s

j u s t o n e c o m p o n e n t o f an i n t e g r a t e d s e t o f m a c h i n e sc o o p e r a t i n g t o w a r d s a c o m m o n t a s k w i th i n th ea u t o m a t e d f a c t o r y. T h e r e f o r e , t h e r o b o t c o n t r o l l an -g u a g e i s e x p e c t e d t o i n t e r a c t w i t h s e v e r a l o t h e rs o f t w a r e m o d u l e s w i t h s e v e r a l l e v e ls o f a b s t r a c t i o nt h r o u g h w h i c h t h e w h o l e m a n u f a c t u r i n g c e l l ( o rc o m b i n a t i o n o f c e l ls ) is m o d e l l e d .

B o t h o b s e r v a t i o n s i m p l y a st r o n g d e m a n d f o r : m a c h i n e i n d e p e n d e n c e , i . e. h i g h f l e x i b il i ty a n d

c o n f i g u r a b i l i t y o f t h e c o n t r o l l a n g u a g e w i t hr e s p e c t t o t h e c o m p u t i n g e n v i r o n m e n t

r o b o t i n d e p e n d e n c e , i. e. a d a p t a b i l i t y t o a v a r i e t y

o f d i f f e r e n t r o b o t s .T h e s e c r i t e r i a e n t a i l a c l e a r i d e n t i f i c a t i o n a n d

sep a ra t io n o f log ica l l eve l s . As an in i t i a l approx i -m a t i o n f o r t h e p u r p o s e s o f th i s p a p e r, w e d i s t i n g u i sht h e f o l l o w i n g t h r e e l e v e l s o f a b s t r a c t i o n :1 . a lo w e r l e v e l , w h i c h i n c l u d e s t h e h a r d w a r e o f th e

r o b o t ( s ) , l o w l e v e l s e n s o r s a n d a s s o c i a t e d c o m p u -t e r ( s ) p l u s g e n e r a l p u r p o s e s o f t w a r e

2 . a n i n t e r m e d i a t e l e v e l c o n s i s ti n g o f a m i n i m a l s e to f r o b o t i c f u n c t io n s

3 . a h i g h e r l ev e l w h i c h v i e w s th e r o b o t s y s t e m o n l yt h r o u g h i t s a b s t r a c t r e p r e s e n t a t i o n i n l e v e l 2 , a n d

w h i c h d e a l s w i t h h i g h l e v e l s e n s o r y p r o c e s s i n ga n d a s s e m b l y p l a n n i n g .I n o u r v i e w t h e i n t e r m e d i a t e l e v e l l a n g u a g e is a

k e y c o m p o n e n t o f t h e o v e r a l l sy s t em . C a r e f u l d e s ig no f it s s t r u c t u r e c a n p l a y a n i m p o r t a n t r o l e i n a c h i ev -i n g t h e g o a l s m e n t i o n e d a b o v e .

2 .2 . Interm edia te level language de finition crtterlaC h o o s i n g t h e a p p r o p r i a t e l e ve l o f a b s t r a c ti o n f o r

t h e i n t e r m e d i a t e l a n g u a g e ( I L ) i n v o l v e s m a k i n gc o m p r o m i s e s o n s e v e r a l c o n fl ic t in g n e e d s : gen e ra l i t y vs . spec i f i c i ty

e f f i c i e n c y v s . e x p r e s s i v e n e s s c o n c i s e n e s s v s. a c c u r a c y o f r e p r e s e n t a t i o n .P r e v i o u s e x p e r i e n c e s s u g g e s te d t h e f o r m u l a t i o n o f

t h e f o l l o w i n g c r i t e r i a f o r I L : t h e v i r tu a l m a c h i n e s h o u l d h a v e a s i m p l e st a c k -

o r i e n t e d s t r u c t u r e I L s h o u l d s u p p o r t a r e s t r ic t e d s e t o f g e n e r a l p u r -

p o s e a n d r o b o t i c s - o r i e n t e d d a t a t y p e s I L s h o u l d p r o v i d e f a c il i ti e s f o r c o n c u r r e n t p r o g -

r a m m i n g I L sh o u l d al lo w s t r u c t u r e d p r o g r a m m i n g t h r o u g h

a p p r o p r i a t e c o n t r o l s t r u c t u r e s , p r o c e d u r e d e f i n i -t i o n s a n d r e c u r s i o n


3/9

V M L i n r o b o t p r o g r a m m i n g P. B IS ONe t a l . 1 3

I L s h o u l d a l l o w i n t e rf a c i n g w i t h e x t e r n a l p r o c e -d u r e s

I L s h o u l d b e i n t e r p r e t e d a n d p r o v i d e o n - l in ei n t e r a c ti o n , s im p l e d e b u g g i n g a n d a n " u n d o " f e a -tu re

I L s h o u l d b e i m p l e m e n t e d i n P a s c a l o r a si m i la rh i g h - l e v e l l a n g u a g e .

2 .3 . Consideration o f portability and m odularityP o r t a b i li t y f o r a r o b o t p r o g r a m m i n g l a n g u a g e

i n v o l v e s t w o f a c t o r s : c o m p u t e r i n d e p e n d e n c e a n dr o b o t i n d e p e n d e n c e .

C o m p u t e r i n d e p e n d e n c e h a s l o n g b e e n i n v e s ti -g a t e d a n d m a n y a p p r o a c h e s h a v e b e e n p r o p o s e d .O u r s o l u t i o n l i m i t s it s e l f t o a d o p t i n g a f a i r l y s t a n -d a r d i z e d h i g h - l e v e l l a n g u a g e l i k e P a s c a l f o r i m p l e -

m e n t a t i o n a n d t o e n c a p s u l a t i n g m a c h i n e - s p e c i f i cf e a t u r e s i n t o w e l l - d e fi n e d i n t e rc h a n g e a b l e m o d u l e s .

R o b o t i n d e p e n d e n c e is a m o r e c o n t r o v e r s i a l s u b -j e c t . 26 W e b e l i e v e t h a t a d e c i si v e c o n t r i b u t i o n w i llc o m e f r o m t h e i n t e g r a t i o n o f s e v e ra l i n t e l l ig e n t to o l sw i t h i n t h e p r o g r a m m i n g e n v i r o n m e n t s ( i . e . a r o b o td e s c r i p t i o n m o d u l e , a r o b o t s i m u l a t o r, a k n o w l e d g eb a s e o n e x i s t i n g r o b o t , o n - l i n e d e s i g n a s s i s ta n c e ,e t c . 4 . 2 ) . C o n s i d e r i n g t h i s f r a m e w o r k , a c a r e f u ld e s i g n o f t h e i n t e r m e d i a t e l e v e l l a n g u a g e s h o u l dp r o v e a d v a n t a g e o u s .

T h e l a n g u a g e d e p e n d s o n t h e i n d i v i d u a l r o b o t i n

m a n y w a y s . L e t u s c o n s i d e r t h r e e l i m i t i n g c a s e s :1 . t w o r o b o t s o f t h e s a m e m o d e l in t w o d i f f e r e n t

o p e r a t i n g c o n t e x t s : d u e t o c a l i b r a t i o n a n de n v i r o n m e n t a l d i f f e r e n ce s , t h e s a m e l a n g u a g es t a t e m e n t c a n p r o d u c e d i f f e re n t e ff e c ts

2 . t w o d i f f e r e n t r o b o t s p e r f o r m i n g s i m i l a r a c t i o n s :l o w - l e v e l h a r d w a r e d i f f e r e n c e s c a u s e t h e s a m es t a t e m e n t t o p r o d u c e d i f f e r e n t p i e c e s o f m a c h i n ec o d e f o r t h e t w o r o b o t s

3 . t w o d i f f e r e n t r o b o t s , e a c h p e r f o r m i n g a c t i o n sp h y s i c a l l y i m p o s s i b l e f o r t h e o t h e r : f u n c t i o n a la n d s t r u c t u r a l d i f f e r e n c e s r e q u i r e d i f f e r e n t li n g-

u i s t i c f ea tu res .F o r e x a m p le , t h e s t a t e m e n t " m o v e t o f r a m e A " is

m e a n i n g f u l f o r b o t h a C a r t e s i a n a n d a j o in t r o b o t ,a l t h o u g h i t p r o b a b l y t r a n s l a t e s i n t o d i f f e r e n tm a c h i n e c o d e b l oc k s .

We h a v e i s o la t e d a " r o b o t k e r n e l " i n c l u d in g am i n i m a l s e t o f f u n c t i o n a l i t ie s w h i c h w e b e l i e v ea p p l i e s t o a w i d e v a r i e t y o f e x i s ti n g r o b o t s . T h ek e r n e l i t s e lf sh o u l d c o n t a i n m e c h a n i s m s t o i n t e r f a c ew i t h t h e r o b o t - s p e c i f i c m o d u l e s n e c e s s a r y t o p r o -g r a m a r e a l m a n i p u l a t o r. F o r e x a m p l e , i n o r d e r t oe s t a b l i s h a m o d e l f o r m o t i o n i n s t r u c t i o n s , w e c a n

s i m p l y r e f e r t o t h e c o n c e p t o f a m u l t i - a r m r o b o t

/ / /


4/9

14 Robotics & Computer-Integrated Manufacturing Volume 5, Numb er 1, 1989

c u r r e n t p r o c e s s e s a n d f o r m u t u a l l y e x c l u s i v er e s o u r c e a c c e s s .

i t i s d e s i g n e d a c c o r d i n g t o F i n k e l ' s g u i d e l in e s f o ra b s t r a c t m a c h i n e m o d e l l i n g ~2 t o i n c r e a s e t h ep o r t a b i l i t y o f t h e l a n g u a g e , a n d r e a l i z e s a t y p e o f

m a c h i n e l a n g u ag e f o r m a n i p u l a t o r p r o g r a m m i n g( li k e t h e a s s e m b l e r f o r a Vo n N e u m a n n c o m p u -te r ) .

i t i s s t r u c t u r e d c o m p a c t l y a n d e l e g a n t l y, in o r d e rt o o b t a i n r e a d a b l e p r o g r a m s ; i n a d d i t i o n , t h ei n t e r p r e t e r a l l o w s s t e p - b y - s t e p e x e c u t i o n o f s i n g l ep r o c e s s e s f o r i n t e r a c t i v e t e s t i n g a n d d e b u g g i n g .

T h e d e s ig n o f V M L s o u g h t t o ex p l o i t t h e c o n c u r r e n tp r o g r a m m i n g c a p a b il it ie s o f f e r e d b y t h e d i s t ri b u t e da r c h i t e c t u r e o f th e s y s t e m . C o n c u r r e n t p r o c e s s e s c a ni n v o l v e t h e f o l l o w i n g a c t i o n s :

( i) c o m p u t a t i o n o f e x p r e s s i o n s i n v o l v in g e i t h e r

l o g i c - a r i t h m e t i c o b j e c t s o r p h y s ic a l v a lu e s ;( ii ) s e q u e n c e s o f c o m m a n d s f o r s e n s o r s a n dm o t o r s ;

( ii i) i n t e r r u p t i o n o f s e r v ic e r o u t i n e s a n d I / O m e s -sages .

T h e m o d u l a r a n d s t r u c t u r e d a r c h i t e c t u r e o f t h eV M L i n t e r p r e t e r a l l o w s t h e u s e r t o e a s i l y a d d h i so w n c o d e d m o d u l e s t o e x t e n d t h e o r i g i n a l s e t o fr o b o t c o n t r o l fu n c t i o n s : V M L is p a r t i c u l a r l y s u it a b l ea s a t a rg e t f o r s t r u c t u r e d r o b o t l a n g u a g e s . 6

A s i m p l e b u t e f f i c i e n t w a y o f i n t e r r u p t i n g t h es c h e d u l e r , b o t h f r o m t h e u p p e r a n d f r o m t h e l o w e r

l e ve l , w a s i m p l e m e n t e d . A u t o m a t i c c r a s h p r o t e c t i o ni n t e r r u p ts m o v e f r o m t h e l o w l e v el t o t h e i n t e r p r e t e ra n d a u t o m a t i c q u e r i e s t o t h e m i c r o s a t th e l o w l e v ela r e a n s w e r e d b y V M L ; i n t e r r u p t s m a y c o m e f r o mt h e h i g h l e v e l a s w e l l , i n o r d e r t o b r e a k t h e r u n n i n gp r o c e s s a t t h e o p e r a t o r ' s r e q u e s t .

3 . O V E R V I E W O F V M L S O F T WA R EA R C H I T E C T U R E

T h e f i r st i m p l e m e n t a t i o n o f V M L w a s b a s e d o nt h e h a r d w a r e f r a m e w o r k d e v e l o p e d a t M i l a n P o l y -t e c h n i c f o r t h e c o n t r o l o f t h e S u p e r s i g m a r o b o t . S I n

t hi s f r a m e w o r k t h r e e l e ve l s o f a b s t r a c ti o n m a y b ed i s t i n g u i s h e d a c c o r d i n g t o t h e d e s c r i p t i o n i n s e c t i o n2 .1 : l o w l e v e l : t h e m i c r o a r c h i t e c t u r e i s d r i v e n b y a

s o f t w a r e s y s t e m w h i c h d i r e c t l y h a n d l e s m o t o r s ,a c t u a t o r s a n d s e n s o r s ; i t a l s o i m p l e m e n t s a c r a s hp r o t e c t i o n f a c i l i t y w h i c h p r e v e n t s c o l l i s i o n s b e t -w e e n t h e a r m s .

i n t e r m e d i a t e l e v e l : t h e t a rg e t s o f t w a r e c o r e c o n -s i s t i n g o f a p e r m a n e n t l y r e s i d e n t r e a l - t i m e l a n -g u a g e i n t e r p r e t e r , t h e V M L w r i t t e n i n P a s c a l ,w h i c h h a s r e p l a c e d t h e M A L c o m p i l e r . 1 3

h i g h l e v e l: a n in t e r a c t i v e p r o g r a m m i n g e n v i r o n -m e n t f o r m e c h a n i c a l a s s e m b l y.In th i s way, a s t r i c t ly h i e ra rch ica l con t ro l s t ruc -

t u r e 9 w a s a c h i e v e d w h e r e c o m m u n i c a t i o n s b e t w e e nl e v e l s w e r e d e f i n e d b y s u i ta b l e p r o t o c o l s ; e a c h p h y s -i c al l e v e l, b o t h o f h a r d w a r e a n d s o f t w a r e , c o r r e -s p o n d s t o a d i f f e r e n t l e v e l o f a b s t r a c t i o n o f r o b o tf u n c t i o n a l a c t iv i t y. E a c h l e v e l h a s f u ll a n d e x c l u s i v ec o n t r o l o v e r t h e n e x t l o w e r l e v e l . T h e s o f t w a r e ,w h i c h c o m m u n i c a t e s w i t h t h e l o w e s t l e v e l , i sr e s p o n s ib l e f o r t h e d i r e ct c o n t r o l o f m a n i p u l a t o rm o t o r s , a c t u a t o r s a n d s e n s o r s . C o m m a n d s a r e t h e n

s e n t f r o m t h e h i g h e r l e v e l s to t h e l o w e r l e v e l s , w h i l es e n s o r i n f o r m a t i o n i s c o l l e c t e d f r o m l o w l e v e l s t oh i g h . I n t h i s w a y, a s y n c h r o n o u s c o m m u n i c a t i o no c c u r s b e t w e e n t h e r o b o t a n d t h e v i r t u a l m a c h i n e ,a n d b e t w e e n t h e v i r t u a l m a c h i n e a n d t h e o p e r a t o r.

I n t h e t r a d e - o f f o f c o m p l e x i t y a n d p o w e r o n o n eh a n d , v e r s u s s i m p l i c i ty a n d e f f i c i e n c y o n t h e o t h e r,t h e fi rs t i m p l e m e n t a t i o n o f V M L w a s d e v e l o p e dw i th r e f e r e n c e t o th i s f u n d a m e n t a l h a r d w a r e c o n t r o lm o d e l . O t h e r m o d e l s r e a l i z e a r i c h e r f u n c t i o n a ls t r u c t u r e c a p a b l e o f m o r e f l e x i b l e b e h a v i o r m s en -s o r y i n t e r a c t i o n . H o w e v e r, w e b e l i e v e t h a t t h i s

m o d e l i s s t i l l a d e q u a t e f o r m a n y i n d u s t r i a l m a n u -f a c t u r i n g a p p l i c a t io n s .T h e i n t e r m e d i a t e l e v el c o r r e s p o n d s t o t h e r e a l-

t im e c o m m a n d l a n g u a g e w e c a ll t h e Vi r t u a l M a c h i n eL a n g u a g e . V M L ' s d e s i g n is b a s e d o n t h e f o l l o w i n ggu ide l ines : i t m a n a g e s b o t h s i n g le a n d c o m p l e x a c t i v it i es ,

e a c h c o r r e s p o n d i n g t o e i t h e r a p h y s i c a l o r a na b s t r a c t p r o c e s s .

i t a ll o w s I / O c o m m u n i c a t i o n b e t w e e n t h eo p e r a t o r , s e n s o rs a n d m o t o r s , a n d p r o v i d e s fo rt h e e x c h a n g e o f e r r o r c o n d i t i o n s .

i t o f f e r s th e b a s i c p r i m i t i v e s f o r c o o r d i n a t i n g c o n -

4 . C O M P A R I N G V M L W I T H O T H E R R O B O TL A N G U A G E S

T h e t a sk o f d e v e l o p i n g r e li a b le , s t r u c t u r e d a n dp o r t a b l e p r o g r a m m i n g l a n g u a g e s f o r r o b o t m a n i p u -l a ti o n o f m e c h a m c a l a s s e m b li e s 7 h a s b e e n t a c k l e db o t h b y a c a d e m i c i n s t i t u t i o n s a n d i n d u s t r i a l c o m -p a n i e s w h o s e r e s e a r c h e r s h a v e t r i e d e i t h e r t oi m p r o v e e x i st in g l an g u a g e s a t th e " m a n i p u l a t o rl e v e l " o r to d e v e l o p n e w a d v a n c e d s o f t w a r e s y st e m sa t t h e " t a s k l e v e l " .

W h i l e t h e t a s k l e v e l s y s t e m s a r e s t i l l u n d e r i n v e s -t i g a t io n , 18 t h e i n d u s t r ia l s c e n a r i o a t t h e m a n i p u l a t o rl e v e l i s m o r e s e t t le d . 5 "1 5 W e d e s i g n e d V M L t os i g n i f i c a n t l y i m p r o v e f i r s t g e n e r a t i o n i n d u s t r i a lr o b o t l a n g u a g e s ( l ik e O l i v e t tl ' S S I G L A 24 a n dD E A ' s H e l p , ~l l a t e r a d o p t e d b y G e n e r a l E l e c tr ic )b y o f f e r i n g a n a d v a n c e d p o r t a b l e t o o l f o r in t e r fa c i n ga m a n i p u l a t o r w i t h s e c o n d g e n e r a t i o n i n d u s t r i a l


5/9

VML m robot programming P. Bison e t a l . 15

r o b o t l a n g u a g e s ( li k e t h e I B M ' s A M L 27 a n d U n i m a -t i o n ' s V A L - I I ) . 25

I n s p i r e d b y S t a n f o r d ' s A L p r o j e c t , 19 V M L h a sb e e n d e s i g n e d a s t h e t a rg e t f o r a w i d e r c la s s o f r o b o tl a n g u a g e s. I ts d e s ig n t h e r e f o r e r e p r e s e n t s a n e f f o r t

t o p r o d u c e a n i n t e r m e d i a t e s t r u c t u r e d t a r g e t l a n -g u a g e , n o t o n l y f o r r o b o t i n d u s tr i a l l an g u a g e s , b u ta l so f o r m o r e a d v a n c e d s o f t w a r e s y s t e m s c a p a b l e o fi n t e g r a t i n g s e v e r a l i n t e r a c t i v e t o o l s a n d a w o r d d e s -c r i p ti o n b a s e d o n f r a m e c o o r d i n a t e a b s t r a c ti o n . 17

I f w e a t t e m p t t o c o m p a r e V M L w i th V A L , 25h o w e v e r, w e m a y f i n d s o m e s i m i l a r i t i e s . F i r s t , w eh a v e a s e t o f e q u i v a l e n t i n s t r u c t i o n s i n b o t h l a n -g u a g e s ( i . e . s o m e m o n i t o r i n s t r u c t i o n s , s o m e I / Oi n s t ru c t i o n s a n d s o m e l o w l e v e l p r o g r a m f l o w c o n -t r o l ) . S e c o n d , s o m e V M L i n s t r u c t i o n s m a y f i n d ad i r e c t t r a n s l a t i o n i n t o a s u i t a b l e s e t o f VA L i n s t r u c -

t i o n s a n d v i c e v e r s a ( s u c h a s r e l a t i v e a n d a b s o l u t em o t i o n c o m m a n d s ; r o b o t , a r m a n d jo i n t p o s it i o nq u e r i e s ; t o o l i n g o p e r a t i o n s ; p a r k i n g r o b o t c a l i-b r a t i o n ; a n d s p e e d s e t t i n g ) .

T h e d i f f e re n c e s b e t w e e n V M L a n d V A L i n cl u d et h e s y n c h r o n i z a t i o n p r i m i t i v e s p r e s e n t i n V M L b u tn o t i n VA L , a n d t h e h i g h l e v el p r o g r a m f l o w c o n t r o li n VA L w h i c h V M L l a c k s . I n a d d i t i o n V M L a l s ol a c k s c e r t a i n VA L i n s t r u c t i o n s u s e f u l f o r i n t e r -a c t i v e l y d e f i n i n g a n d s t o r i n g l o c a t i o n s , f o r c a l i -b r a t i n g a n d r e s e t t i n g v a r i o u s s y s t e m d e v i c e s , f o rc h o o s i n g a r m c o n f i g u r a t i o n a n d m a k i n g s o m e p a r t i -

c u l a r m o v e m e n t s . H o w e v e r , n o n e o f t h e s e s p ec i fi ci n s t r u c t i o n s h a v e b e e n c o n s i d e r e d p r i m i t i v e o p e r a -t io n s f o r t h e v i r tu a l m a c h i n e . M o r e o v e r , V M L w a sd e s i g n e d a s a s t a c k o r i e n t e d l a n g u a g e f o r t h e p u r -p o s e s o f e f f i c i e n c y.

T h e c o m p a r i s o n w i t h A M L 27 i s m u c h l e ss m e a n -i n g f u l . A M L i s a n e w g e n e r a l - p u r p o s e l a n g u a g e ,e x t e n d e d w i t h t h e f u n c t i o n s n e e d e d t o o p e r a t er o b o t s ; i t s d e s i g n a l l o w s s u b r o u t i n e s t o b e w r i t t e na n d u s e d l i k e b u i l t - i n c o m m a n d s , w h i l e V M L a c t sm a i n l y a s a n i n t e r m e d i a t e l a n g u a g e . We h a v ed e v e l o p e d a m a c r o p r o c e s s o r f o r V M L w h i c h m a y b e

u s e d t o p r e d e f i n e a n i n s t r u c t i o n s u b s e t t o b e u s e dl a t e r , b u t t h is f a c il i ty is e x t r a n e o u s t o t h e l a n g u a g ed e f i n i t i o n a n d b e l o n g s r a t h e r t o t h e p r o g r a m m i n ge n v i r o n m e n t t o o l s e t .

F r o m t h e p o i n t o f e x t e n d i b i l i t y, i t i s i n t e r e s t i n g t oc o m p a r e V M L w i th t h e l an g u a g e I R D A TA 2 3 w h i chh a s b e e n d e s i g n e d b y a c o m m i t t e e o f G e r m a n i n st i-t u t e s a s t h e G e r m a n t a r g e t l a n g u a g e o f th e E x p l i c i tP r o g r a m m i n g S y s t e m , w h i c h w i l l b e d e v e l o p e d b yt h e E s p r it R e s e a r c h P r o j e c t o n O p e r a t i o n a l C o n t r o lf o r R o b o t S y s t e m I n t e g ra t i o n in t o C I M ( V M Li n d e e d i s a s u i t a b l e c a n d i d a t e a s t h e I t a l i a n t a rg e tl a n g u a g e i n t h e s a m e E s p r i t p r o j e c t ) . A n

I R D AT A p r o g r a m is a s eq u e n c e o f r e c o r d s w h i c hc o n t a i n s a c e r t a i n n u m b e r o f a r g u m e n t s a n d w h i c hm a y b e c l a s s i f i e d b y d i s t i n g u i s h i n g d e s c r i p t i v e e l e -m e n t s f r o m a c t i o n e l e m e n t s a c c o r d i n g t o t h e s p ec i alr e q u i r e m e n t s o f r o b o t p r o g r a m m i n g . V M L h a s qu i te

t h e s a m e s e t o f c a p a b i li t i e s w i t h r e g a r d t o t h e d e s -c r i p ti o n o f r o b o t f e a t u r e s , m o t i o n s p e c if i ca t io n s ,p r o g r a m f l o w c o n t r o l , I / O o p e r a t i o n s a n d d a t a t y p em a n i p u l a t i o n . V M L , h o w e v e r , i s a m o r e s t r u c t u r e da n d r e a d a b l e l a n g u a g e ; i t i s l i k e l y t h a t i n t h e n e a rf u tu r e b o th I R D A TA a n d V M L w ill b e e n h a n ce da n d e x t e n d e d t o i n c l u d e f e a t u r e s o f t h e n e x t -g e n e r a t i o n r o b o t c o n t r o l l a n g u a g e .

5 . M A I N L A N G U A G E F E AT U R E SI n t h e f o l l o w i n g , w e s h a l l d e s c r i b e t h e m a i n

i n s t ru c t i o n s u b s e ts o f V M L . T h e f o r m a l d e s c r i p t i o n

o f th e l a n g u a ge c a n b e f o u n d i n t h e V M L U s e rM a n u a l . 3 A V M L s t a t e m e n t is c o m p o s e d o f a no p t i o n a l la b e l, a c o m m a n d k e y w o r d w h i c h m a y b ef o l l o w e d b y a t y p e k e y w o r d , a n d a li st o f a r g u m e n t s :

( s t a t e m e n t ) : : = [ ( l a b e l ) ] : ( o p c o d e ) [ ( t a g f i e l d ) ][ ( o p e r a n d s ) ] .

A V M L p r o g r a m c o m p r i s e s t w o m a i n p a r ts : ag l o b a l d a t a d e c l a r a t i o n a n d a c o n c u r r e n t p r o c e s sd e c l a r a t io n . T h e f o r m e r a ll o w s th e d e c l a r a t i o n o fc o n s t a n t s , a r r a y s o f c o n s t a n t s , g l o b a l v a r i a b l e s ,g l o b a l a r r a y s , s e m a p h o r e s , m a i l b o x e s a n d g l o b a l

p r o c e d u r e s . I n c o n t r a s t , e a c h i n d i v id u a l ly d e c l a r e dp r o c e s s m a y h a v e i ts o w n d e c l a r a t i o n p a r t f o r m e d b ya l a b e l d e c l a r a t i o n , l o c a l v a r i a b l e a n d a r r a y d e f i n i -t i o n a n d l o c a l p r o c e d u r e d e c l a r a t i o n .

C o n s t a n t s a n d v a r i a b l e s c a n b e l o n g t o t h e f o l lo w -i n g d a t a t y p e s : i n t e g e r, s c a l a r ( r e a l ) , B o o l e a n , g e o -m e t r i c v e c t o r , r o t a t i o n , f r a m e a n d c h a r a c t e r s t r i n g .A r r a y s m a y b e c o m p o s e d o f s c al a rs , v e c to r s , r o ta -t i o n s a n d f r a m e s .

Tw o p r i m a r y t o o l s f o r p r o c e s s s y n c h r o n i z a t io n a r ea v a i l a b l e t o t h e p r o g r a m m e r : b i n a r y s e m a p h o r e sa n d m e s s a g e s. B i n a r y s e m a p h o r e s a r e a c c e s se d b y

t h r e e i n st ru c ti o ns : WA I T, S I G N A L a n d T E S T-W A I T . T h e f ir st tw o p r i m i t i v e s h a v e t h e u s u a l m e a n -i n g , w h i l e t h e t h i r d t e s t s t h e s e m a p h o r e ' s s t a t e a n di ss u es a " W A I T s e m " i f t h e s e m a p h o r e is f r e e . I na n y c a s e i t r e t u r n s a B o o l e a n v a l u e w h i c h c o r r e -s p o n d s t o t h e s t a t e b e f o r e t h e o p e r a t i o n . M e s s a g e sa r e s e n t o r r e c e i v e d t h r o u g h a m a i l b o x b y t w oi n st ru c ti o ns : S E N D a n d R E C E I V E .

T h e c o n t r o l f l o w m a y b e a l t e r e d i n t w o w a y s : b yl o c al o r e x t e r n a l p r o c e d u r e c a ll s o r b y c o n d i t i o n a l o ru n c o n d i t i o n a l b r a n c h e s .

I / O i n s t r u c ti o n s a ll o w c o m m u n i c a t i o n b e t w e e n

t h e V M L i n t e r p r e te r a n d a h u m a n o p e r a t o r . A s e t o f


6/9


7/9

VML in robot programming P. BISON t a l .

PUSH VALUE up; PUSH VALUE leftarm;MOVE ARM REL;{update the displacement subtracting the cubesize}PUSH VALUE linc; PUSH VALUE edge;

MINUS; POP VALUE linc;

WA IT m utu a; {beginning of critical and region}{compute where to put the cube and movethere}PUSH VALUE arrind; PUSHARRAYVALUE pos;PUSH VALUE defrot; PACK FRAME;PUSH VALU E leftarm; MOVE AR M ABS;{release the cube}PUSH VALUE down; PUSH VALUEleftarm; MOVE ARM REL;PUSH VALUE open; PUSH VALUEleftarm; TOOL ;PUSH VALUE up; PUSH VALUE leftarm;MOVE ARM REL;{move over the left cube stack}PUSH VALUE lpos; PUSH VALUEleftarm; MOVE ARM ABS;{test if all positions in the line have a cube}PUSH VALUE arrind; INC; POP VALUEarrind;PUSH VALUE ncubes; COMPARE GT;

SIGNAL mutua; {end of critical region}

{jump to the end if the previous test was true}BRANCH COND endpr;{if there's some cube in the stack, take it}PUSH VALUE count; INC; POP VALUEcount;PUSH VALUE lcubes; BRANCH LE loop;

endpr:PUSH VALUE leftarm; PARK ARM;FLUSH;{park the arm and clear the stack}

END;

The code for the right-arm process is exactlysymmetric to this: it contains a REC EIV E statementcorresponding to the SEND in the above code, andall "lefthand" variables (like linc, lpos, etc.) arechanged to rightarm variables (rinc, rpos etc.).

6 . T H E O P E R AT I N G E N V I R O N M E N TWhile the next generation of robot programming

systems will provide for increasing integration ofsensing and motion with task p lanning capabilities, itproves convenient to develop an advanced pro-

gramming environment for the existing robot lan-

17

guages which may allow for betteroperator-machine interaction.

Among the criteria which guide a reasonableapproach to the design of a software environmentfor robotics, we may select the following:

the coexistence and interaction of different"loosely connected" software modules, possiblywritten in different languages

these modules must provide a simulator of robotkinematics driven by robot language motionstatements

the programmer needs a set of primitives formanipulating robot programs, accessmg a robotassembly library and storing coded utilities.We believe that software environments for robot

programming will continue to grow in the future.Task level robot programming will be achieved by

integrating different components within a sophisti-cated distributed system rather than by defining asingle complex language satisfying all possiblerequirements. Previous considerations lead us toconsider the manipulator-operator interfacing soft-ware system as an open system 16 in which the r obotlanguage mterpreter acts as one of the modules.

Therefore, as a first step, we developed a friendlyinteractive environment around the present versionof VML interpreter. The original VML interpreterwas written in Pascal except for a small part writtenin Assembly which interfaces to the particular hard-

ware. Our scheduler implements a round-robin algo-rithm, while dynamic memory m anagemen t is basedon the allocation of fixed memory areas to avoidgarbage collection.

The system layout (see Fig. 5) is composed of asmall kernel, called monitor, which provides systemfacilities such as clock management, scheduling andmemory allocation, plus several virtual processors

J PROCESSORn j

Fig 5. Structure of tile VML example program.


8/9

18 Robotics & Compu ter-Integrated Manufacturing Volume 5, Numb er 1, 1989

5 r B D h l c ~ e o r e s e n t a t i o n i n

A

// ,

/

i/

/

VML In te rpr et er 2 . 0

~VML> PARK ROBOT.

// /

//iF_rJ

MONITORTEACH BOX

W M

READYOPEN/CLOSELEFTY/RIGHTYBELOW/ABOVESPEEDEXIT

Fig 6 A screen snapshot of the VML graphics envzronment under developmen t at LADSE B

w i t h t h e i r o w n p r i v a t e m e m o r i e s w h i c h c o m m u n i -c a te t h r o u g h a c o m m o n d a t a a r e a .

V M L w a s f i r s t i m p l e m e n t e d o n a n e a r l i e r m u l t i -m i c r o p r o c e s s o r st r u c t u r e c o n t r o l l i n g a t w o - a r mO l i v e t t i m a n i p u l a t o r a t M i l a n P o l y t e c h n i c . S i m p l es y n c h r o n i z a t i o n p r i m i t i v e s , l i k e WA I T / S I G N A La n d S E N D / R E C E I V E , a l lo w e d c o n c u rr e n t p r o -

g r a m m i n g o v e r a s ta r - st r u c tu r e d n e t w o r k f o r m e d b ys o m e I n t e l 8 7 4 8 8 - b i t m i c r o s a n d a n L S I - 11 .A t L A D S E B , V M L p r e s e n t l y r u n s o n a d i s t r i -

b u t e d h a r d w a r e s t ru c t u re b a s e d o n t h e V M E b u s ,w h i c h i s a c c e s s i b l e t h r o u g h t h e g r a p h i c i n t e r a c t i v ee n v i r o n m e n t o f t h e M a c i n t o sh .

A s a s e c o n d s t e p t o w a r d s t h e r e a l i z a ti o n o f a no p e n s y s te m , w e u n d e r t o o k t o d e v e l o p a h i g h- l ev e lg r a ph i c e n v i r o n m e n t . 10 T h u s , a t L A D S E B w e b e g a nb y d e si g n in g a k i n e m a t i c s i m u l a t o r f or P U M A , c a p -a b l e o f a c c e p t i n g V M L s t a t e m e n t s p r e v i o u s l y tr a n s -l a t e d i n t o VA L i n s t r u c t i o n s . O u r s i m u l a t o r ( s e eF i g . 6 ), b a s e d o n P a u l ' s k i n e m a t i c e q u a t i o n s , 21 h a s

b e e n i m p l e m e n t e d o n a I C L - P e r q g r a p h i c s w o r k -s t at io n 4 w h e r e i t ca n e x e c u t e V M L p r o g r a m s .

We a l so p la n t o im p l e m e n t a m o r e a d v a n c e di n t er a c ti v e e n v i r o n m e n t f o r r o b o t - p r o g r a m m i n gb a s e d o n m e s s a g e - p a s s i n g s e m a n t i c s 2 i n t h e c o n t e x to f th e A c c e n t O p e r a t i n g S y s t e m , z2 w h e r e t h e V M Li n t e r p r e te r r u n s a s a n i n d e p e n d e n t m o d u l e a n dc o m m u n i c a t e s w i t h o t h e r t o o l s v i a m e s s a g ee x c h a n g e . T h e U n i v e r s it y o f P a d u a , i n c o o p e r a t i o nw i t h a n I t a l i a n i n d u s t r i a l f i r m , h a s r e w r i t t e n t h eV M L i n t o s o u r c e c o d e s C l a n g u a g e t o o b t a i n a m o r ee f f i c i e n t s y s t e m a n d t r a n s p o r t i t i n t o a n i n d u s t r i a le n v i r o n m e n t .

R E F E R E N C E S1. Bison, P. , Loren zln, G., Pagello, E.: The form al defin-

I t i on o f VML and a p roposed po r t ab l e imp le -men ta t i on . Proceedings of the llth 1S1R, To k y o ,Oc tobe r 1981 . pp . 585 -594 .

2 . Bison, P, Pagel lo , E . , Rodighiero , F. , Traml to , G. .The deve lopmen t o f a po r t ab l e p rog ramming l an -


9/9

VML in robot programming P. BISON t al. 19

guage for manipulator control. Proceedmgs the Con-ference on the Autom at ton of Indus t r ia l Processes ,Kempe, V., Menga, G. (Eds.). Tormo, DesignersRiuniti Editon 1983. pp. 221-227.

3. Bison, P., Toset to, A.: VML-Versione 2.0: Manualed'uso e gulda all'implementazione. Techmcal Report

LAD SEB -CN R 85-01 Padova, January 1985.4. Bison, P., Pagello, E., Priolo, L., Zivlam, S.: Simu-lation tools as a programming aid for robot pro-grammmg. In Languages for Sensor-Based Cont ro l inRobot tcs , Rembold, U., Hormann, K. (Eds.). NAT OASI Series: Computer and System Sciences, Berlin,Springer, 1987.

5. Blume, C., Jakob, W.: Prog rammmg Languag e s f o rIndus t r ia l Robots .Berlin, Springer, 1986.

6 Blume, C., Jakob, W.: Design of the structured robotlanguage (SRL). In Advanced So f twa re m Rob o t i c s ,Dauthine, A., Gerardln, N. (Ed s), Amsterdam,North Holland, 1984. pp. 127-143.

7 Bonner, S. Shin, K.G.: A comparative study of robotlanguages. C o m p u t e r 15: 82-96, 1982.

8. Cassmls, R : An example o f a distributed intelligencediscrete process controller. Dtgttal Syst . Ind. Automat.1: 45-77, 1981

9 Cassinis, R.: Hierarchical control of integrated man-ufacturing systems. Proceedm gs o f the 13th IS1R.Chicago, April 1983, pp 12/9-12/20.

10. Dlllmann, R.: A graphical emulation system for robotdesign and program testing. Proceedmgs of the 13thIS1R. Chicago, April 1983, pp. 7/1-7/15.

11 Dona to, G., Camera, A : A high level programminglanguage for a new multiarm robot. Proceedings of the1s t l n te rna tt on a l C on fer ence on Au to ma ted Assem b ly.Brighton, 1980. Kempston, Bedford, IFS, 1980,pp. 67-76

12. Fmkel, R A.: Constructing and debugging manipu-lator programs. SAIL Memo AIM-284, StanfordUniversity, Stanford, 1976.

13. Gini, R., Gmse, D.: MAL: hnguaggio di program-mazlone per robot; Descrizione generale. TechnicalRepor t No 78-20. Department of Electronics, MilanPolytechnic, Milan, January 1979

14. Gmi, G., Gini, M., Pagelio, E., Trainlto, G.: Distri-buted robot programming. Proceedm gs o f the l OthIS1R. Milan, March 1980, pp. 61-71.

15. Gruver, W A., Soroka, B I., Craig, J.J., Turner, T .L.:

Evaluation o f commercially available robot pro-grammlng languages, Proceedings of 13th ISIR .Chicago, April 1983, pp. 12/58-12/68.

16. Hewltt, C.: The challenge of open systems. Byte 10:223-242, 1985.

17. Laugier, C.: Robot programming using a high level

language and CAD facilities. In Robo t Tec hno logyAp ph c a t t on s , Rathmlll, K., MacConail, P.,O'Leary, S., Browne, J. (Eds.). Berlin, Springer,1985, pp. 187-199.

18. Lozano-Perez, T.: Robot programming. Proc. 1EEE71: 821-841, 1983

19. Multaba , S., Goldman, R.: AI User' s Manual. ReportNo. STAN-CS-81-889, Stanford University, Stanford,December 1981.

20. Pagello, E., Bison, P., Mlrolo, C, Penm, G., Tramlto,G.: A message passing approach to robot pro-grammlng. Comput . Ind . 7: 237-247, 1986.

21. Paul, R.L.: Ro bot Manipula tors Mathemat ics , Prog-r am m i ng and C on t ro l .Cambridge, MIT Press, 1981.

22. Rashld, R.F.: Experiences in the design, implementa-tion and use of network operating systems. Pro-cee dm gs o f the A IC A- 8 4 Co nf e rence .Roma, October1984, pp. 137-156.

23 Rembold, U., Blume, C., Frommherz, B.J.: The pro-posed robot software Interfaces SRL and IRDATA.Robot ics Comput- ln tegr. Mfg2: 219-225, 1985.

24. Salmon, M.: SIG LA: the Olivetti Sigma robo t pro-gramming language. Proceedings of the 8 th ISIR.Stuttgart, May 1978, pp. 358-363.

25. Shlmano, B.E., Gesche, C.C., Spalding, C.H. III:VAL-II: a robot programming language and controlsystem. In Ro botics Research The First InternationalS y m p o s i u m .Brady, M., Paul, R. (Eds.). Cambridge,MIT Press, 1984, pp. 917-940.

26. Soroka, B.I.: What can't robot languages do? Pro-ceedings of the 13th ISIR,Chicago, April 1983,pp. 12/1-12/8.

27. Taylor, R.H., Summers, P.D., Meyer, J.M.: AML: amanufacturing language. In t . J . Robot tcs Res . 1:19-41, 1982.

28. Opera t tona l Cont ro l for Ro bot Sys tem In tegrat ion mtoCIM: Sys tem Plannmg, Exphct t and Impl ic i t Pro-g r a m m i n g . ESPRIT-CIM-5.4.2 Robot Systems Pro-ject No. 623. Techmcal Annex. Spur, G. (Ed.). IPK,Berlin, January 1985.

am intermediate language for robot programming

Documents