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Proceedingsof the 1996 IEEEISICEIRSJ International Conference on M ultisensor Fusion and Integration for Intelligent Systems

Automatic Operation of a Combined H arvester in a Rice FieldJun-ichi SATO, Kazuto SHIGETA, Yoshisada NAGASAKA

Department of Farm Mechanization, National Agriculture Research Center,Tsukuba, Ibaraki, 3 0 5 Japan

AbstractWhen a head- feed ing com bined harves ter harves t s

r i ce i n t h e f i e l d , t h e o p er a t o r o n b o a r d i s exp o s ed t on o i s e a n d t h e d u s t f r o m t h e s t r a w. A u t o m a t i copera t ion , tha t i s wi thout an opera tor on boa rd ,wo u l d cer t a i n ly e l im i n a t e s u ch a p r o b l em . A j o i n tresearch t eam organized by N ARC a n d Mi t s u b i s h iF a r m M a c h i n e r y Co. , Ltd . , has developed and tes tedan au tomat ic opera t ing t echnique us ing the head-f eed i n g co m b i n ed h a r vest e r wh i ch i s p o p u l a r a m o n gJa p a n es e f a r m er s . Th i s a u to -co m b i n e h a s no v i s u a lsensor . I t s opera t ion sys tem includes a s t ra igh t l ineautomat ic ope ra t ion which fo l lo ws the rows of r icep l a n t s , a n d t u r n in g a c t i o n a t t h e en d o f t h e f i e l dwh i ch i s s u p p o rt ed b y a co m p u t er w i t h s ever a l k i n d sof sensors . To determine whether the au to-combinecould carry ou t au tomat ic harves t ing opera t ionwi t h o u t a n o p er a to r o n b o a r d i n a r i ce f i e l d , t h ea u t o m a t i c f o r w a r d t r a ve li n g of t h e co m b i n e f o l l o w i n gt h e r o ws of r ice p lan t s , and the au tomat ic turn ing b ythe computer i zed program were t es ted . The au to-co m b i n e p r o ved t o b e a s p r a c t i ca l a s i t d e s i g ned t obe . Th i s new automat ic opera t ing sys tem en ables oneopera tor to opera te two or more au to-combiness i m u l ta n eo u s ly i n a r i ce f i e l d .Key words: agr icu l tura l mechaniza t ion , au tomat icopera t ion , combined harves ter ,

1 IntroductionAgr icul tura l mechaniza t ion has advanced

remarkably in recent years . Yet , in te rms of a

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hea l thy envi ronment for f a rmers who opera te sucmachines on board. cur rent commerc ia l f a rmachines st i l l have much to be desired, especial1:when such machines a re opera ted for many hourTh e vibra t ion an d noise of such machines can bpotent ia l ly harmful to the hea l th of the opera toFur thermore , the o pera tor on board the Japanese typhead- feeding combined harves te r ( combine) may bexposed to a lo t of s t r aw dust . Machines which cabe opera ted more comfor tably and sa fe ly by thopera tor a re there for be ing demanded by fa rmerFuture mech aniza t ion technology should be geared the physica l comfor t and sa fe ty of the machinopera tor a t the maximum poss ible leve l in the samway as i t has been used to achieve high eff iciencand prec is ion.A n automat ica l ly opera ted machine ? i .e . f a rrobot wi th no hum an opera tor r equi red to operathe machine on board, i s ce r ta inly a viable means providing comfor t and sa fe ty for the opera toOpera tor s of combines a re exposed to excess ivamounts of noise and dus t whi le working. n .hich cabe in jur ious to the i r hea l th . Thus , a more advanceharves t ing technology was des igned and deve lopejoint ly by the Nat iona l Agr icul ture Research Centand Mitsubishi Farm Machinery Co. Ltd. . to produca n exper imenta l combine w hic h does no t require aopera tor on board dur ing th e opera t ion.commerc ia l type combine was modif ied in to a"auto-combine" , which the jo int r esearch teains ta l led wi th an automat ic opera t ing sys teconsis t ing of severa l sens ing devices and ac tua torun by a microcomputer .

2 T he auto-combine

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2.1 Ma in fea tures o f the "auto -combine" w e igh t i s 3040kg (Table 1).

There a re two big di f fe rences be tween Japaneseand convent iona l (European- type) combinedha r ve s t e rs . Whole p l a n t s w i th g r a in a nd s t r a w a r e f e dinto the convent iona l combine , whi le only the headsof r ice plants a re fed to th e Japanese type . Secondly,t he J a pa ne se t ype ha s d iv ide r s a nd p i c k - up de v ic e s i nf ront of the cut te r bar , which cor respond to the rowsof r ice plants (F ig . 1 and 2) .

m-Conveyer

Fig .1 Head Feeding Combine

Pick-up Devicei t

Threshing Cylinder Grain Head Divider

Pick-up Devicei t

Threshing Cylinder Grain Head Divider

Ta ble 1. Specif icat ions o f the CombineL e n g t h ( m m ) 4.250W i d t h ( m m ) 11,895H e igh t ( mm) 2 , 5 9 5G r o s s W e i g h t ( k g ) 3 . 4 0E ng ine O utpu t ( kW/ r pm) 3 ) / : I , 400C o n t a c t P r e s s u re ( k g / c m 2 ) 0 . 2 3

2.2 Automat ic travel ing contro l system of thecombine

Fig .2 Mechanism of Head Feeding Combine

1) Automatic control devices of a head-feedingc ombine .A head- feeding combine of' the la tes t model hasbeen provided wi th some automat ic cont rol devicesfor e f f ic ient harves t ing W O I k . Ma jo r a u toma t i ccont rol i tems inc lude feeding depth cont rol ,t r ave l ing speed cont rol , cut t ing he ight cont rol andleve l ing cont rol . In addi t ion to the above , Anautomat ic t r ave l ing cont rol sys tem was ins ta l led inthe auto-combine .2 )cont rol sys tem

The auto-combine ha s been provided wi th var ioussensors which a re requi red to the methods for sensorintegra t ion. The sensors whic i a r e c onne c t e d w i ththe a u toma t i c t r a ve l ing c on t r o l a r e show n in F ig .3 .

Sensor equipm ent for autom at ic t r ave l ing

The working width of the combine which wasused for the test is 120cm covering 4 rows of crops.The combine was ins ta l led wi th a pa i r of t r acks ast rave l ing devises . The t r acks a re dr iven by enginepower c rea ted through the hydros ta t ic t r ansmiss ion(HS T) . S teer ing is per formed by a s tee r ing c lutch andbr a ke o n the t r ansmiss ion of the t r ave l ing gearins ta l led wi th t r ack . The engine power i s 30kw and

Contact SensorsFig. 3 Sensors on the Combine

0 ontac t senso rs which touch the s ta lks of r iceplants a re ins ta l led on the dividers in f ront of thecut te r bar . They a re used fo r d i rec t iona l cont rol of

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the com bine t r ave l ing a long rows of r ice plants .0 gyroscope used as a n a z imuth se nsor i s t he

sa me s imple a nd i ne xpe ns ive t ype use d as anaviga t ion device in automobi les .

@ A leve l sensor to de tec t the leve l of gra in i n th egr a in t a nk i s i n s t al l ed i n t he t a nk . T he c ompute rca lcula tes permiss ible harves t ing dis tances f rom theva lues of the leve l sensor an d other func t ions .

@ A pulse counte r , which measures the revolut ionof a prope l lant axis . i s used as a sensor to measurethe t r ave l ing dis tance and speed of the combine .

@ A cut t ing he ight sensor cont rols the cut te r barhe ight above ground leve l dur ing th e cut t ing of c rops .8 he over load sensors de tec t b lockage by r ice

s t raw.In the pas t , the automat ic cont rol device was as imple one connec t ing a se nsor a nd a n ac tua tor

th r ough a re lay. Today, severa l sensors have beenconnec ted in complex fashion wi th severa l ac tua tor sth r ough a n on- boa r d c ompute r ( F ig . 4) .

Contact Sens orsContact Sens orsContact Sens orsContact Sens orsContact Sensors

Revolut ion Sens or Cut t ing he ight Sens or

Fig .4 Sensor System Block Diagram3) Automat ic t r ave l ing cont ro l sys tem

The automat ic t r ave l ing cont rol sys tem consis t sof three sub-cont rol sys tems: the forward t r ave l ingcont rol sys tem which fol lows r ice plants rows.automat ic turning cont rol a t the edge of a f ie ld . andautomat ic working suspended cont rol .0 Automat ic forward t r ave l ing cont rol

In s t ra ight forward t r ave l ing in the paddy f ie ld .two contac t sensors (A 1 a n d A2) o n the oute r s ide ofthe divider guide the combine a long the rows ofp l a n t s ( F ig .5 ) . ( In the fol lowing t r ip of the combinea f t e r t u r n ing . B1 a nd B2 c ha nge t o t he gu ida nc esensors . ) In order to prevent the wrong judgment to

a r r i ve a t t he e dge o f f i e l d , w he n t h e r e a r e some l a c kof rice plants in the ou te rmost row, th is con t rolsuppor ted by the other contac t sensors B a n d C , a nthe combine keeps t r ave l ing forward. I f the acontac t sensors on t he d iv ide r s a r e i n no - c on t acondi t ion, the cont rol sys tem checks whether thva lue which was me a sur e d f o r t r a ve l i ng d i s t a ncf r om the f i e ld e nd c o r r e sponds t o t he l e ng th o f t hpaddy f ie ld , because i t i s cons idered tha t the a l l r icp l a n t s i n t he 4 r ow s i n w h ic h t he c ombine t r a ve l i npa th a r e l a c ked w i th in sho r t d i s t a nc e ( F ig .6 ) .

Turn RiehtI

Follow tripI

,. n- -----Cutter Bar r ~-. -L"

3

Fig .5 Contact Sensors on D iv iders

C o nti 11ueS t r a i g h t T r a v e l i n g

form En d o f FieldVTrrrninetart c t ion

Fig. 6 Flow D iagram of

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@ Autom atic turn in g contro l a t the edge of a f ieldAt the edge of f ie ld , the com bine is tu rned by the

ro ta t ing speed contro l of bo th s ide t racks . The r ightand lef t hand s ide tracks cha nge speed independent lythrough the HST t ransmiss ion which is contro l led bythe computer (Fig .7) . The turn ing d irect ion of thecombine is controlled by the integrated value of theoutput f rom a gyroscope ins ta l led on the body. Theprocess of tu rn ing with two 90 degree turns fo l lowsthe ins t ruct ions of the computer program (Fig .8) .The output of the gyroscope was in i t ia l ized to cancelthe in i t ia l value sh if ting with t im e whi le the combineis t ravel ing forward , and fo l lowing the s t ra ight l ineof the plant rows at every working tr ip.

Tur n L e f tIpeed Sh i f t Levery o n t r o l M o to r

1 1 \1

T r a n s m i s s i o n E

Fig. 7 Turning Mechanism

Straight Trave ling Initialize Gyrosc ope

"'L& En d of RowsDistance Colinter

l=!wvcsting IFig. 8 Flow Diagram of Turnin g Action

4 ) Automatic working suspended control.

When the amoun t o f g r a in in t he combine 's g r a intank approaches its capacity, 1he on-bo(ard com puters imulates the ra te of gra in increase in the tank us ingthe working t ime and the t ravel ing d is tance f rom thein i t ia l condi t ion on the f ie ld , and calcu la tes apos i t ion to suspend operat ions . The combine s topswork at the ed ge of the f ield just before the followingtr ip in which gra in would s tar t to over f low f rom thetank .

3 Methods3.1 Experimental f ie ld amd r ice plants

The d imens ions of the exper imenta l paddy f ie ldwere 30m by loom , the s tand ard s ize of a paddy f ie ldin Japan . Th e r ice p lan ts , which were grown 130days af ter t ranspla nt ing in the spr ing , were 100-130cm tall . Rice plants in each row were spaced15cm apa rt, w ith rows 30cm aF1art (Figs . 9and 10 ) .rl I Adjacent Field 1 1*

f---------- F=c)Traveling Trip--

F-

! ? I~IOOm -p?I n z i c e n t i ield

Fig. 9 Dimensions of Field and Traveling Trip

Fig. 10 Rice Plants Rows in Paddy Field

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3.2 W o r k methodTh e opera tor does not dr ive the auto-combine on

boa r d . O n ly w he n t he g r a in t a nk o f t he c ombine i sful l wi th harves ted r ice . does the opera tor conduc t ama nua l ope r a t i on a d i s c ha r ge c onve ye r . T h i s a u to -combine has a r emote radio cont rol le r which theopera tor uses to re turn the combine to the f ront ofrows in the next t r ip .

At the edge of the f ie ld , the combine can turn byme a ns o f a n a u toma t i c s t e e r i ng ope r a t i on . a nd t he nautomat ica l ly cont inue to harves t in the fol lowingt r ip . When the leve l sensor in the gra in tank s igna lstha t gra in leve l capac i ty i s be ing reached. thecombine a r r ives and s tops work i t se l f a t the edge ofthe f ie ld and wai ts for the opera tor outs ide thef ie ld to s ta r t the discharge conveyer . Af te rdischarging the gra in , the combine i s led by remotecont rol to the next t r ip by the opera tor . The opera torc a n a l so c ha nge t he c on t ro l sys t e m f rom the ma nua lremote cont rol mode to the auto-prope l mode .

4 Results of the experim ent andconsidera tion4.1 Automatic forward travel ing control

The auto-combine was dr iven e r ror less ly a longthe rows of r ice plants by the automat ic forwardt rave l ing cont rol . The s tee r ing of the combine wascont rol led by shor t braking to s top one of the twotracks . This autom at ic s tee r ing was car r ied out s tablyaccording t o the two contac t sensors o n the outs idedivider and the computer program.

4.2 Turning act ion at the edge of thepaddy f ie ld

T ur n ing o f t he c ombine i s c on t r o l le d a c c or d ing t o

the program ins ta l led in the computer ized cont rol leWhe n the c ombine r e a c he s t he e dge o f t he f i e ld . tcontac t sensors perce ive tha t there a re no more r ip lants growing beyond tha t point . Af te r perce ivithe end of a row. the combine cont inues to most ra ight forward unt i l the re a re no r ice planimme dia t ely be ne a th i t s body .

I 90cm II71 Center of Turning

Fig. 1 1 Turning Act ionThe cont rol le r then s tops the harves t ing ac t ion a

l i f t s the cut t ing head severa l seconds la te r . At tsame t ime . the body of the combine i s d i rec ted t u r n a t a n a ng l e o f 90 degrees by the gyroscocont rol . Then. the combine moves forward fordis tance of 90cm toward to th e next t r ip . of fe r whii t a u toma t i c a l l y ma ke s a no the r 90 de gr e e t u r n aente r s the next rows (Fig .11) . When a l l contasensors on the divider check and show the cor reposi t ion to ente r the next rows. the combine resumits work. I n t h i s e xpe r ime n t t he c on t a c t s e nsoaccura te ly perce ived a nd de tec ted the end of the roa t the edge of the f ie ld . The prec is ion of the degree turns which were cont rol led wi th tgyroscope was c lose enough for prac t ica l use . In tf in ish pos i t ion of the combine a f te r a turning ac t iothe a l lowable e r ror f rom the re fe rence va lue of td is tance be tween the s ide l ine of the divider and toutermost row of r ice plants w a s approximate ly1 c m ( F ig . 12 ) . Occas iona l ly . the dis tance e r rexceeded a l lowable e r ror when the f ie ld w as mudor had an i r regula r sur face .

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th is new automat ic operat ing sys tem. This methodwil l be appl ied to p lowing and spraying and o therf ie ld operat ions . In the near fu ture , au tomat icimplements such as th is au to-combine wil l be widelyused in paddy f ie lds , and their opera tors wi l l no thave to be on board . Ins tead , the job of the operatorswil l be to suppor t the operat ion of the au tomat icmachine s f rom the s ide of the f ie ld

6 Summary1) In order to free an operator of a head-feedingcombine f rom tasks producing dus t , an au tomat ict ravel ing contro l combine which requires no operatorto operate on board was developed an d tes ted .2) The au tomat ic t ravel ing contro l sys tem cons istsof three sub contro l sys tems , i .e . , a s t ra ight forwardtravel ing contro l system. au tomat ic turn ing contro l a tthe edge of a f ie ld , and au tom at ic working suspendedcontro l . This contro l sys tem has no v isual sens ingequ ipmen t .3) Th e au tomat ic forward t ravel ing contro l wi th thecontact sensors and computer program guided thecombine smooth ly a long the rows of r ice p lan ts4) Th e au tomat ic turn ing contro l a t the edge of afield was performed by the sensor fusion whichconsis ted of contact sensors on the divider, agyroscope installed on the body. the counting sensorof the t rack ro ta t ion as t ravel ing d is tances an d theon-board computer .5 ) The combine operator d id not have to beengaged in any phys ical work , whi le au to-combineharvesting by the automatic self-control system.Fur thermore . the operator was ab le to put anotherauto-combine in to operat ion in an ad jacent f ie ld . Inth is new automat ic operat ing sys tem. therefore twoor more auto-combines can be operatedsimultaneously by a s ingle operator.

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agr icu l tura l robots (Par t 1) . J . Jpn. Soc. Agric.

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Mach in . , 46, 353-358. ( In Japanese wi th Engl is ummary ) . 1984Kondo, N. 1995) : A harves t ing robot based the phys ical proper t ies of a grapevine . JAQOsamu Yukimoto , Yosuke Matsuo , Research Autonomous Land Vehic le for Agr icu l tureARBIP9.5, Jpn.Soc.,4gric.,Lfachin, ol. 1, pp.448, 1995.Jun-ichi Sato, kazuto Sigeta . Development Semiautomat ic Operat ing Technology for LigTractors in Paddy Fie lds , ARBIP9.5, Jpn. SoAgric. Machin, Vol . 1 , pp.65-72 , 1995.

29(3) , 171-177.