Computers in the Laboratory - American Chemical Society

2 Robots and Robotics in the Laboratory: What Does It Mean? CHARLES H.

LOCHMÜLLER

Downloaded by NANYANG TECHNOLOGICAL UNIV on June 2, 2017 | http://pubs.acs.org Publication Date: October 5, 1984 | doi: 10.1021/bk-1984-0265.ch002

Paul M. Gross Chemical Laboratory, Duke University, Durham, NC 27706

This paper addresses the limited current state- of-art in laboratory robotics and compares i t to current manufacturing practice. Important questions are: "When is automation robotics?", "What is a robot anyway?" and "Where does a robot fit in a laboratory environment.?" Examples of current applications are reviewed and suggestions for future directions are presented. The i d e a o f a robot i n the l a b o r a t o r y i s a t once a f a m i l i a r and a very strange concept. P a r t o f the p r o b l e m i s the a s s o c i a t i o n by many o f the word ROBOT w i t h a v a r i e t y o f ambulatory m e c h a n i c a l automatons of different degrees o f s o p h i s t i c a t i o n . Currently a v a i l a b l e r o b o t s are a d i s a p p o i n t m e n t t o many as they a r e neither as c l e v e r as R2D2 n o r as human as C3P0 o f STARWARS fame. In fact, the v a s t m a j o r i t y o f c u r r e n t r o b o t s are r e a l l y a r m - l i k e machines w i t h v a r y i n g s t r e n g t h and d e x t e r i t y ; some a r e c a p a b l e o f moving hundreds o f k i l o s and o f p l a c i n g such o b j e c t s w i t h i n f r a c t i o n s o f a centimeter w h i l e o t h e r s m a n i p u l a t e gram masses t o s u b - m i l l i m e t e r precision. They resemble p a r t s o f the common concept o f a robot more than a w h o l e . Nevertheless, the p r e v i o u s p a r a g r a p h p r o v i d e s the k e r n e l o f a d e f i n i t i o n for a robot. " A m e c h a n i c a l d e v i c e w h i c h performs comp l e x t a s k s w i t h h u m a n - l i k e s k i l l " may be a l i t t l e too g e n e r a l but is a good w o r k i n g d e f i n i t i o n . The word r o b o t d e r i v e s from the R u s s i a n f o r " w o r k e r " o r " t o work" and human work o f t e n requires s i g n i f i c a n t mechanical s k i l l . C o n s i d e r then t h a t c u r r e n t l a b o r a t o r y robots are, i n essence, "blind, one-armed men" and you immediately a r r i v e at the crude n a t u r e they p o s s e s s . Current robots do n o t have t r u e human s k i l l but many common t a s k s are accomplished s a t i s f a c t o r i l y given t h e i r inherent handicaps.

A u t o m a t i o n vs R o b o t i c s How

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r o b o t ( w h i c h i s used t o

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0097-6156/84/0265-0011$06.00/0 © 1984 A m e r i c a n C h e m i c a l Society

Liscouski; Computers in the Laboratory ACS Symposium Series; American Chemical Society: Washington, DC, 1984.

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C O M P U T E R S IN T H E LABORATORY

d i f f e r e n t from an automated i n s t r u m e n t (which c o u l d be d e s i g n e d t o p e r f o r m t h e same t a s k ) ? That i s n o t an easy q u e s t i o n t o answer b u t a r e f e r e n c e t o m a n u f a c t u r i n g r o b o t s may p r o v i d e some c l u e . There i s a g r e a t d e a l o f d i f f e r e n c e between a " r o b o t o c i z e d " p r o d u c t i o n l i n e and an automated one. Automated p r o d u c t i o n works w e l l i n s i t u a t i o n s i n which t h e p r o d u c t i s c o m p l e t e l y s t a n d a r d i z e d and a l l s p a t i a l c h a r a c t e r i s t i c s a r e f i x e d - e.g.- b o t t l i n g soda. The advantage o f r o b o t i c s i s i n t h e a b i l i t y t o adapt t o new p r o d u c t c h a r a c t e r i s t i c s - e.g.- a complete body change on t h e "'84 model" i n a welding o r spraying operation. An " i n d u s t r i a l " r o b o t i s a "reprogrammable. m e c h a n i c a l d e v i c e which performs complex t a s k s w i t h human-like s k i l l " . I t i s t h i s reprogrammable o r r e t r a i n a b l e a s p e c t t h a t makes t h e r o b o t a t t r a c t i v e from an e n g i n e e r i n g view point. Of c o u r s e , even a r o b o t assembly l i n e i s n o t c o m p l e t e l y r e t r a i n a b l e - i . e . - auto assembly p l a n t s cannot become t e x t i l e m i l l s by s i m p i e s o f t w a r e f i x e s . Not u n r e a s o n a b l y , t h e same i s t r u e o f current laboratory robots but, e s p e c i a l l y i n a r o u t i n e determina t i o n f u n c t i o n - e.g.- q u a l i t y c o n t r o l - where t h e c h e m i c a l "unit o p e r a t i o n s " a r e very s i m i l a r i n procedures involving radically different analytes, the r e t r a i n i n g f e a t u r e i s an extremely d e s i r a b l e advantage. T r a i n i n g a. Robot Robots which a r e r e q u i r e d t o mimic complex human motion - i . e . - t h e s p r a y p a i n t i n g o f a u t o m o b i l e s by a 20-year v e t e r a n p a i n t e r - w i l l r e q u i r e very s o p h i s t i c a t e d t r a i n i n g u t i l i t i e s i n the c o n t r o l l e r / o p e r a t i n g system. I n f a c t , such r o b o t s " l e a r n " by b e i n g l e d through a t a s k "hand-in-hand" w i t h a s k i l l e d human o p e r a t o r . Such a continuous t r a n s d u c t i o n o f p o s i t i o n speed and d i r e c t i o n i n t o a c o n t r o l program i s v e r y e x p e n s i v e . No l a b o r a t o r y r o b o t available today u t i l i z e s such a t r a i n i n g scheme. I n f a c t , c u r r e n t r o b o t s a r e l e d t h r o u g h a sequence o f s t e p s which a r e i n d i v i d u a l l y "programmed" by an o p e r a t o r t o r e p r e s e n t a u n i t o p e r a t i o n - e.g.- " p o u r " , " t a r e " , "weigh", " d i l u t e " , " d i s p e n s e " , " t a k e a l i q u o t " - which a r e l i n k e d t o become a program t o make t h e r o b o t c a r r y o u t a p a r t i c u l a r t a s k - e g - "Do 100 immunoassays - Type 1". Again the d i f f e r e n c e from a u t o m a t i o n i s t h a t t h e same r o b o t c a n , a f t e r f i n i s h i n g t h e immunoassays, b e g i n a new t a s k - " P r e p a r e 20 v i t a m i n assay samples - Type 3". A r e a l requirement f o r c u r r e n t r o b o t s i s a t o t a l l y f i x e d c o o r d i n a t e system. C u r r e n t r o b o t s cannot f i n d a tube r a c k on a t a b l e t o p , t h e y s i m p l y go t o where a tube r a c k " i s supposed t o be".

Robots; Types and C o o r d i n a t e Systems C u r r e n t l a b o r a t o r y r o b o t o p e r a t i o n s use many o f t h e i n s t r u m e n t modules f a m i l i a r i n c o n v e n t i o n a l a u t o m a t i o n : syringe drives, relay d r i v e r s , c u r r e n t and/or v o l t a g e s e n s o r s ( i n c l u d i n g Α/Ό c o n v e r s i o n ) etc. The u n i q u e l y r o b o t i c component i s a " p i c k and p l a c e " arm which s e r v e s as a "mass mover" o f sample, s o l u t i o n e t c . from one u n i t operation to the next. The r o b o t c o n t r o l l e r f u n c t i o n s t o c o n t r o l b o t h t h e p i c k - a n d - p l a c e component and t h e s e p a r a t e unit operations. A c t u a l l y i t i s poor p r a c t i c e t o s e p a r a t e any o f t h e



2.

LOCHMULLER

Robots and Robotics

in the Lab

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f u n c t i o n s o f a r o b o t i c system and d e c i d e t h a t i t i s t h e r o b o t i c element. I t i s the system t h a t i s reprogrammable o r r e t r a i n a b l e and s h o u l d be thought o f a s an e n t i t y composed o f numerous functional a b i l i t i e s . L e t us compare the two r o b o t t y p e s c u r r e n t l y a v a i l a b l e comm e r c i a l l y f o r use ( o r adapted f o r use) i n l a b o r a t o r y environments: Zymate ( d e v e l o p e d by Zymark C o r p . , H o p k i n t o n , Mass.) and M i c r o b o t A l p h a (manufactured by M i c r o b o t , I n c . , Mountain View, CA b u t adapted by G. Owens and co-workers o f the P r o c t e r and Gamble Advanced I n s t r u m e n t a t i o n Group, C i n c i n n a t i , OH). These two r o b o t s d i f f e r i n major ways each w i t h i t s unique p e r s o n a l i t y and c a p a b i l i ties. The d e t a i l o f i m p l e m e n t a t i o n has been d e a l t w i t h elsewhere (1) and need n o t be dwelt on h e r e . The Zymate i s a r o b o t specifically-built f o r l a b o r a t o r y o p e r a t i o n s and e s p e c i a l l y f o r sample p r e p a r a t i o n . The M i c r o b o t A l p h a i s an assembly r o b o t t y p i c a l o f e l e c t r o n i c s manfacture but w i t h s l i g h t l y p o o r e r posit i o n i n g t o l e r a n c e s than the v e r y b e s t a v a i l a b l e f o r t h a t purpose. Both a r e s t a t i o n a r y r o b o t s ( a l t h o u g h the a d a p t a t i o n o f Owens e t a l . t r a n s l a t e s i n one dimension i n some c o n f i g u r a t i o n s ) r e q u i r i n g p r e c i s e p o s i t i o n i n g o f work p i e c e s i n a c i r c l e around the workplace. N e i t h e r p o s s e s s t a c t i l e o r v i s u a l "sense" i n s t a n d a r d c o n f i g u r a tion. T a c t i l e sense can be a c h i e v e d by m o n i t o r i n g c u r r e n t i n t h e h a n d / f i n g e r s e r v o systems. The Zymate [ F i g u r e 1] moves i n a c y l i n d r i c a l c o o r d i n a t e system ( r o t a t e 370°, r e a c h 60cm, l i f t 56cm) under c o n t r o l o f a m i c r o p r o c e s s o r computer u s i n g DC servomotor and c a b l e d r i v e w i t h potentiometric sensing o f p o s i t i o n . I t p o s s e s s e s a "broken w r i s t " c a p a b l e o f r o t a t i o n (360°) b u t not b e n d i n g . A unique f e a t u r e l i e s i n t h e i n t e r c h a n g a b i l i t y o f the "hands". G r i p p e r hands p e r m i t movement o f tubes and o t h e r v e s s e l s w h i l e s y r i n g e hands can d e l i v e r s m a l l volumes, t a k e a l i q u o t s and, w i t h a d a p t e r s , f i l t e r l i q u i d samples. I n some a p p l i c a t i o n s s p e c i a l hands c o n t r o l instument on/off functions. The M i c r o b o t A l p h a [ F i g u r e 2] i s an a r t i c u l a t e d arm w i t h a 46 i n . h e m i s p h e r i c a l envelope. The arm has a p o s i t i o n i n g a c c u r a c y o f 0.5 mm w i t h i n the e n v e l o p e . I t i s a stepping-motor and c a b l e d r i v e n r o b o t c o n t r o l l e d by a 6502 p r o c e s s o r t h a t communicates v i a an RS-232 i n t e r f a c e t o the " o u t s i d e w o r l d " . L i k e the Zymate, i t can be t r a i n e d u s i n g a hand-held pendant keyboard o r can be e x t e r n a l l y d r i v e n by a l a b o r a t o r y microcomputer. The c o o r d i n a t e system o f a f u l l y a r t i c u l a t e d arm i s more c o m p l i c a t e d than a s i m p l e cyli n d r i c a l system b u t t h i s i s overcome by s o f t w a r e c o n t r o l . The advantage i s t h a t the A l p h a can bend i t s " w r i s t " t o r e a c h into t i g h t , a n g l e d q u a r t e r s such as when tubes must be removed from a s l a n t - t u b e c e n t r i f u g e head. Current A p p l i c a t i o n s Robots a r e b e s t s u i t e d ( i n t h e i r p r e s e n t form) f o r t e d i o u s , r e p e t i t i v e and humanly-hazardous j o b s . T a b l e t a n a l y s i s , immunoassay d e t e r m i n a t i o n s , polymer s o l u b i l i t y , e t c a r e i d e a l applications. Less r o u t i n e p e r h a p s , b u t j u s t a s t e d i o u s , a r e s t u d i e s o f enzyme a c t i o n and a c t i v i t y which r e q u i r e v a r i a t i o n i n r e a g e n t s and perhaps incubation timing, the " o p t i m i s a t i o n o f chemical reactions or 1


C O M P U T E R S IN T H E L A B O R A T O R Y


14

F i g u r e 1. The Zymate (Zymark Corp., H o p k i n t o n , MA) showing t h e main r o b o t module ( c e n t e r ) w i t h u n i v e r s a l w r i s t and " g r i p p e r " hand a t t a c h ed. I n t h e upper r i g h t i s t h e c o n t r o l l e r w i t h programming keyboard and s o f t keys ( r i g h t hand s i d e o f d i s p l a y s c r e e n ) . The s o f t keys can be d u p l i c a t e d i n a " t e a c h / l e a r n " pendant (not shown).



F i g u r e 2. The A l p h a ( M i c r o b o t I n c . , M o u n t a i n v i e w , CA) showing: t e a c h i n g pendant ( l o w e r l e f t ) , r o b o t w i t h g r i p p e r a t t a c h e d ( a l t e r n a t e g r i p p e r s i n f r o n t c e n t e r ) , system c o n t r o l l e r and o p e r a t o r c o n t r o l module (lower r i g h t ) . Note how w r i s t can b o t h r o t a t e and bend.



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COMPUTERS IN T H E LABORATORY

routine preparation o f d e r i v a t i v e s i n organic s y s t h e s i s . To d a t e , r o b o t s do n o t d i s p l a c e people by " t a k i n g over t h e i r j o b " because they a r e used i n t a s k s i n which t h e r e i s a h i g h t u r n - o v e r o f p e r s o n n e l due t o boredom. The p e r s o n n e l f r e e d by t h e i n t r o d u c t i o n o f r o b o t s c a n be i n v o l v e d i n more p e r s o n a l l y s a t i s f y i n g t a s k s . In a d d i t i o n , t h e r e i s mounting evidence t h a t t h e use o f r o b o t s g r e a t l y improves b o t h long and s h o r t - t i m e v a r i a n c e i n t h e p r e c i s i o n o f quality control applications. Immediate l a b o r a t o r y r o b o t a p p l i c a t i o n i s p o s s i b l e i n almost any l a b o r a t o r y sample p r e p a r a t i o n program. Robots c u r r e n t l y a v a i l a b l e can and do f u n c t i o n t o p e r f o r m almost a l l o f t h e u n i t o p e r a t i o n s a s s o c i a t e d w i t h sample p r e p a r a t i o n : w e i g h i n g , dissolu tion, c e n t r i f u g a t i o n , reagent dispensing, mixing, incubation, f i l t e r i n g , l i q u i d - l i q u i d e x t r a c t i o n and f i l l i n g sample t r a y s . A l l o f t h i s c a n be performed w i t h complete l o g g i n g o f sample h i s t o r y .

Conelusion There i s l i t t l e t o c o n c l u d e a t p r e s e n t . R o b o t i c s i s an i n f a n t e n g i n e e r i n g d i s c i p l i n e and y e t t h e m a n u f a c t u r i n g a s p e c t o f r o b o t i c i m p l e m e n t a t i o n i s f a r ahead o f any l a b o r a t o r y a p p l i c a t i o n . Today's r o b o t s a r e reprogrammable a u t o m a t i o n , they a r e f a r from b e i n g cybernauts and a r e h a r d l y " c l e v e r " b u t t h e i r p o t e n t i a l as an "arm" f o r a r t i f i c i a l i n t e l l i g e n c e experiments cannot be o v e r l o o k e d .

Literature Cited 1. Analytical Chemistry A/C Interface, Vol 55, 1100A-1114A, 1232Α1242A (1983). RECEIVED

June 5, 1984


Computers in the Laboratory - American Chemical Society

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