Design and Motion Analysis of ROV Robot for Catching Sea Cucumber

Transcription

1 USHEN YU et al: DESN AND OTON ANALYSS O ROV ROBOT OR CATCHN SEA CUCUBER Design and otion Analsis of ROV Robot fo Catching Sea Cucumbe usheng YU *, Haihi UO, Xiaoqin SHEN, Haihen L School of echanical and Electical Engineeing, Shandong Jianhu Univesit, Jinan, 50101, China Abstact n this pape we design a ROV Remotel Opeated Vehicle) sea cucumbe catching obot with a laeed maste/slave contol sstem. The maste contol sstem is manipulated b a human opeato on boad a ship. A cable connects the maste to the slave contol sstem of the obot unde wate, and caies the contol signals fom maste to slave and the senso signals fom slave to maste. Opeatos on boad can obseve the undewate conditions though fou CCDs and contol the obot s motion to achieve the catching wok. The obot is equipped with fou popelles installed on the bod of the obot. The motion of lifting, sinking, lateal and cuve of the obot ae ealied b the popelles. n ode to balance the weight of the obot, gasbags ae installed on the eight cones of the obot. ou adjusting clindes ae adopted to balance the weight of the caught sea cucumbes. The intenal assembl is equipped with gippes designed to pick sea cucumbes. The motion equations of the obot ae given and the mechanics and motion tajecto of the obot ae simulated. The populsion of the popelles in diffeent wate depth is also dnamicall simulated. The esults of the simulation ae in ageement with those of theoetical analsis. Kewods - sea cucumbe; obot; ROV; mechanical stuctue; motion analsis.. NTRODUCTON To begin with we will povide a bief backgound on the sea cucumbes. Nutitional value of the sea cucumbe is ve high, which is now in geat demand. But the health of fisheman is theatened b the wok of catching sea cucumbes. Some sufficient device is needed. The undewate obots that emotel-opeated is ecognied as the pionee, who could eploe and eploit the esouce of the sea. The obot has become an impotant equipment undewate. The obot has widel used in detecting inland dam[1], installing and maintaining maine engineeing stuctues[], seaching and escuing undewate and so on[3]. With the inceasing demand of sea cucumbes, it is ugent to emplo the obot to catch sea cucumbes. At pesent, thee is seldom eseach on the sea cucumbe catching obot. A sea cucumbe catching obot was designed b Tao Zewen. Cleane pinciples was applied in the obot, who could dive into 50m depth [4]. A ROV sea cucumbe catching obot is designed in this pape. The whole stuctue of the obot and its main mechanism ae given. The whole stuctue is designed accoding to the obot s comple woking envionment. The gippe moving mechanism and the popelle populsion mechanism ae also designed. The motion analsis of the obot is caied out though LUENT fluid analsis softwae. Details on pessue clouds of the obot ae discussed in late sections. The etenal foce of the obot in the paticula speed is calculated though LUENT. The analsis could povide a theoetical guidance fo the contol of the obot.. ARCHTECTURE O THE ROBOT The main pupose of the obot is picking sea cucumbes in the wate. Undewate CCD is installed on the outside of the obot to achieve seaching sea cucumbes. Behavioal tansmission, fom opeatos to the obot is achieved though cable. The popelle is mounted on the outside of the obot to povide powe fo it. Woking envionment of the obot is comple, with the iegula distibuted ocks, coals and othe had objects. n ode to potect the obotic shell, the gasbags ae installed on the outside of the obot. The oveall stuctue of the obot is shown in ig cable. cove 3. gasbag 4.shell 5. otated moto 6. popelle mechanism 7. pot 8. intenal assembl 9. CCD outside the machine igue 1. Whole stuctue of the obot. DO / JSSST.a SSN: online, pint

2 USHEN YU et al: DESN AND OTON ANALYSS O ROV ROBOT OR CATCHN SEA CUCUBER ig.1 shows that the cable is designed on the uppe pat of the obot. asbags ae aanged on the eight cones of the obotic shell. The functions of the gasbags ae as follows: it could potect the obot to avoid collision between something had object, it also can balance the gavit and buoanc of the obot. The gasbags could educe the populsion of the popelle, which could save a lot of eneg. A senso is installed on the obot, which can detect the obot s buoanc eal-time. The amount of the ai in the gasbags is contolled b the switch compaed with the obot s gavit. Undewate CCD is installed on the lowe pat of the obot. t is convenient to seach sea cucumbes though CCD. The powe of the obot is povided b the popelle, which is diven b the otated moto and inne watepoof moto.. REALZATON O THE AN ECHANS The sea cucumbe obot mainl consists of two impotant pats. On pat is intenal assembl, whose function is picking and stoing sea cucumbes. Anothe pat is popelle, who can povide powe fo the obot. The moving diection of the obot is detemined b the popelle. A. ntenal Assembl n the intenal assembl, thee has the coesponding component to pick up and conve sea cucumbes. The stuctue of the intenal assembl is shown in ig.. The intenal assembl consists of man sections. On is gippe moving mechanism, whose function is catching sea cucumbes. On is adjusting clinde, which is installed on the chassis. The function of adjusting clinde is balance the gavit and buoanc of the obot. The bag inside of the basket used to stoe the picked sea cucumbes. Belt used to tansmit sea cucumbes. The stuctue of the adjusting clinde is nested. Adjusting clinde will shoten o elongate nested in the pocess of balancing the gavit. The space is saved though the woking was of adjusting clinde. The fence and gaps ae space placed in conveo belt. ippe moving mechanism will etact when the obot seaching o tansfeing sea cucumbes. At the same time, the fence pat of the belt is placed unde the gippe, which can potect the gippe. The gippe moving mechanism will etend when the obot picking sea cucumbes. The gap of the belt will locate unde the gippe at the same time, which povides plent of space fo finge. The powe of the belt is povided b spocket moto. The stuctue of the gippe moving mechanism is etaodina complicated. The gippe moving mechanism consists of man component pats that woking togethe to complete the pocess of picking sea cucumbes. The gippe moving mechanism mainl consists of five pats: finge, opening and closing mechanism of the gippe, telescopic mechanism of the gippe, moving mechanism and otating mechanism of the gippe. We will povide in this section the basic connections between eve pat which ae necessa fo the undestanding of subsequent motion of the gippe. The stuctue of the gippe moving mechanism is shown in ig ippe oving echanism. Chassis 3. Adjusting Clinde 4.Basket 5. Spocket Backet 6. Spocket Wheel 7. Conveo Belt 8. Buckle 9. Bag 10. Spocket oto. igue. Stuctual design of intenal assembl. 1. Disc-Shaped Rotating oto. Rotating Disk 3. Lateal oving Rack 4. uide Tack 5. Sliding Block 6. Slide Plate 7. Lateal ea 8. Lateal oving oto 9. ippe Rota oto 10. ippe Backet 11. uide Rod 1. ippe Telescopic oto 13. ippe Telescopic ea 14. ippe Opening And Closing oto 15. ippe Opening And Closing Nut 16. Connecting Rod Of inge 17. ippe Ccd 18.inge 19. ippe Base igue 3. Stuctual design of gippe moving mechanism. DO / JSSST.a SSN: online, pint

3 USHEN YU et al: DESN AND OTON ANALYSS O ROV ROBOT OR CATCHN SEA CUCUBER The finge is selected to pick sea cucumbes because of its small moving scope and slow moving speed. The finge should moves in all diections in ode to pick up sea cucumbes. Disc-shaped otating moto and otating disk ae connected fiedl to achieve the finge s otation. A guide tack is aanged on the otating disk. The lateal moving ack is mounted on the side of the guide tack. A sliding block is mounted onto the guide tack which can move along the guide tack. The slide plate is aanged on the slide block while lateal moving moto is installed on the slide plate. Lateal moving gea mounted on the output shaft of the lateal moving moto which can move along the ack. The finge moves above the sea cucumbes diven b disc otating moto and the lateal moving moto. Two gippe telescopic motos ae installed on the ea plate of the gippe base. ippe telescopic gea is installed on the output shaft of the gippe telescopic moto which can move along the ack on the gippe backet. Two guide ods ae aanged inside of the gippe backet. ippe base is mounted on the guide od though the guide hole. Ale of the gippe opening and closing moto is equipped with thead. Nut of the gippe is mounted on the ale. One end of the gippe connecting od is mounted on the nut, while anothe end is connected with finge. The middle pat of the finge is installed on the connecting od, which could achieve the finge s otation aound the connecting od. Afte picking sea cucumbes, the finge will move in opposite diections, pepaing fo tansmitting sea cucumbes. B. Popelle echanism The common populsions of the undewate obot ae: moto populsion, hdaulic populsion, watejet populsion, HD agnetohdodnamic Dive), bionic populsion, etc. [5]. oto populsion is selected b analing the advantages and disadvantages of vaious was. Popelle is chose to povide the eneg fo the obot. The positions and the numbes of the popelles ae impotant, which man scholas have done the eseach about it. Lingbo concluded that the undewate obot with otatable thustes onl needs fou popelles to achieve si degees feedom of the obot b analing its foces and moments. The schola also agues the impotance of the install location of the popelles[6]. Wu nailong also undelined the impotance of the install position of the popelle, who had done some eseach accoding to established phsical model[7]. The installation mode of the popelle is adopted etenal hanging manne. The obot could moves in all diections diven b fou popelles, whose diections could be changed. The popelle moto with two shafts is equipped with tubines. Popelle is mounted on the watepoof steppe moto of sealed compatment. Diection of the popelle could be changed b the otation of the steppe moto. Robot could dive into the wate when the outlet of the popelle facing the wate suface. Robot also could moving up when the outlet of the popelle facing the wate bottom. When the diection of the popelles mounted opposite sides of the obot is hoiontal, the obot could move in lateal. When the obot moves in vetical diection, it could achieve tun bow if the speed of the popelles opposite sides of the obot is diffeent. When the obot moves in lateal diection, it could change the diection if the speed of the popelles opposite sides of the obot is diffeent. The shape of the popelle is shown in ig.4. V. igue 4. Popelle mechanism. SEA CUCUBER PCKN PROCESS The gippe moving mechanism and the conveo belt is unde the condition of static when the obot looking fo the sea cucumbes. ence section of the belt is located below the finge, which could potect gippe. The motion of the obot is diven b the popelle mechanism. asbags and adjusting clindes could balance the gavit and buoanc of the obot eal-time. The obot will move towads the sea cucumbes contolled b the opeato, who has found the sea cucumbes though the CCD installed outside of the obot. The opeato will then issue instuctions to the obot to pick up sea cucumbes. The steps of the obot to catch sea cucumbes ae as follows: istl, the position of the gippe moving mechanism is changed diven b the adjusting mechanism. Secondl, conveo gap is located below the gippe diven b spocket moto and then the finge will etend. Thidl, the finge could pick sea cucumbes and then etact. Lastl, conveo fence is located below the gippe again diven b spocket moto. The diection of the sea cucumbes will adjusted diven b the gippe ota moto. Sea cucumbes will finall dop on the fence pat of the belt when the finge opened. The conveo belt will move and bing sea cucumbes to bag. Section above biefl intoduced the pocess of catching sea cucumbes of the obot, while the section below discussed the adjustment pocess of the gippe. DO / JSSST.a SSN: online, pint

4 USHEN YU et al: DESN AND OTON ANALYSS O ROV ROBOT OR CATCHN SEA CUCUBER The position of the gippe moving mechanism needs to adjust in ode to pick sea cucumbes convenientl. The adjust pocess of the position of gippe moving mechanism ae as follows: To begin with, gippe will otate contolled b disc otating moto. Besides, lateal gea moves along the lateal moving ack diven b the lateal moving moto. Last but not the least, the finge will pick sea cucumbes when the finge is located above it cuentl. t needs to tansfe the sea cucumbes to bag afte picking the sea cucumbes. Befoe tansfeing the sea cucumbes, its diections need to adjust. The tansmit pocess ae as follows: ist of all, the diection of the sea cucumbe needs to change. When the diection of the sea cucumbe is pependicula to the moving diection of the conveo, the finge will open. Then, sea cucumbes will fall into the fence section of the conveo. What s moe, the sea cucumbes will move towad bag unde the effect of the belt. inall, the sea cucumbes will fall into stoage bag unde the action of gavit. A fishing peiod is complete. V. OTON ANALYSS AND SULATON O UNDERWATER ROBOT A. otion Analsis of Undewate Robot The moving pocess of the obot undewate is comple. n this section, the motion of the obot is analed biefl. The fied inetial coodinate sstem X, Y, Z) and the obot moving coodinate sstem,, ) ae established, which ae shown in ig.5[9,10,11,1]. mu- wq m u wp m w uq vp P q m[ m[ q ) pq ) p q) X pq ) p ) q P) Y p q) q p) p q ) Z ) q p q) w uq vp) ) p q p) w uq vp) ) pq p q ) q ) pq ) v u wp)] K pq ) p u v wp)] p q) ) q p) 1) ) 3) 4) 5) m[ v u wp) u v wq)] N 6) n the above equations, left sides of the equations ae the inetial foce and moment of the obot. The ight sides of the equations ae the etenal foce and outside toques of the obot. Smbols used in the left sides of equations ae in accodance with the standad method of annotation. V 0 =u,v,w) T and w=p,q,) ae the component of the thee dimensional linea and angula velocit of the obot in its moving coodinate sstem. The etenal foce 0 =X,Y,Z) T and the outside toques 0 =K,,N) T ae the esultant foce and esultant toques, which ae assumed that it consists of fluid static esilience, towline tension and wate dnamics. So that: 0 W T H TH 7) 0 W T n the Equation 7) and Equation 8) above, the subscipt W epesents the fluid static esilience, while T epesents the towline tension and H epesentative of the hdodnamic foce on the main bod of the obot. TH epesents populsion of the popelle. n the equations above, the etenal foce 0 and etenal toque 0 of the obot can be calculated b means of CDcomputational fluid dnamics). n the net section, the motion simulation of the undewate obot is given. H TH 8) igue 5. Coodinate sstem diagam of undewate obot. The moving equations of the obot can be obtained in the obot moving coodinate sstem. The equations ae as follows [1]: B. otion Simulation of Undewate Robot The moving pocess of the obot unde wate is complicated. The vetical movement and lateal movement ae analed in the pape. The powe of the obot is povided b the popelle. The esistance and the pessue distibution DO / JSSST.a SSN: online, pint

5 USHEN YU et al: DESN AND OTON ANALYSS O ROV ROBOT OR CATCHN SEA CUCUBER of the obot can be obtained though its moving analsis. Sufficient populsion of the popelle is need fo the obot moving ahead. The coesponding contol poject can be obtained though the populsion of the popelle, which could achieve the moving contol of the obot. The vetical movement of the obot consists of upwad movement and downwad movement. The analsis model of the obot should be built in ode to simulate its moving pocess. The analsis models of the obot ae diffeent in its diffeent moving diection. Clinde is selected to be the contol domain accoding to the shapes of the obot and the amount of the calculation. Phsical model of the obot and its contol domain ae established in SolidWoks. The model and the contol domain wee impoted into ANSYS to analsis. The diamete of the obot the outside diamete) is D. The diamete of the contol domain is 5D while its length is 10D. The distance between inlet bounda and the cente position of the obot is 4D while the distance between outlet bounda and the obot is 6D. The gid mesh of the model is geneated in CE. Tetahedon is selected to mesh the obot conside its complicated appeaance. The maimum sie of the gid is 300mm, while the total of the gid is about two million. The gid was impoted into LUENT to analsis. The tubulence model of the obot is the standad k-ε model. The inlet bounda condition is set into velocit, whose value is 5m/s. The outlet condition is set into pessue outlet, and the outlet pessue is 0. The outside bounda of the contol domain is set into wall bounda conditions. Eve suface of the obot is set into wall bounda conditions. The pessue clouds ae shown in ig.6. The effect of the pessue cloud automatic displa is unsatisfacto, whee the compaison of the pessue of eve pat is not evident. The maimum visual pessue is selected 10 4 Pa. The tajecto diagam of the obot is shown in ig.7. a) pessue cloud of the obot fo upwad movement b) pessue cloud of the obot fo downwad movement c) vetical view of pessue cloud fo upwad movement d) vetical view of pessue cloud fo downwad movement e) bottom view of pessue cloud fo upwad movement f) bottom view pessue cloud fo downwad movement igue.6 Pessue cloud of the obot Pa). We can intepet the esults of the epeiments above as in the following sections. ig.6a shows that the pessue of eve pat of the obot is diffeent when the obot moving upwad. The geatest pessue appeas on the cove, the uppe suface of the gasbags and the popelles. The negative pessue is eists in the outside of the obot. The wate flows along the suface of the obot at the cetain speed in the pocess of the obot s movement, which can educe the pessue of the suface. The negative pessue will be bigge if inceasing the velocit of flow. ig.6c and the ig.6e give the concens that the pessue on the inlet diection of the obot is bigge than the pessue on the outlet diection. Pessue on the outlet diection is bigge than othe position s which is caused b the wake flow in the pocess of the movement. ig.6b shows that the pessue distibutions ae completel diffeent fom pessue distibutions when the obot moving upwad. The geatest pessue appeas on the pot, lowe suface of the gasbags and popelles. The negative pessue also eists in the outside of the obot. ig.6d and the ig.6f give the concens that the pessue on the pot is bigge than the pessue on the cove, which is caused b the obot s moving diection. The pessue of the DO / JSSST.a SSN: online, pint

6 USHEN YU et al: DESN AND OTON ANALYSS O ROV ROBOT OR CATCHN SEA CUCUBER cove is bigge than othe position s, which is also caused b the wake flow. b) Pessue cloud of the obot in inlet diection a) Tajecto of the obot moving upwad b) Tajecto of the obot moving downwad igue 7. Tajecto of the obot. ig.7 shows that the tajecto of the obot is staight without othe distubance. We will anale the tajecto of the obot with distubance in ou net eseach. The esistance of the obot is calculated in the LUENT. We can pint the pessue when the obot moving upwad. The pessue foce of the obot is 64N, whee the viscous foce is 913N. The total foce of the obot is 977N. The total populsion of the popelle is 977N, whee the populsion of eve popelle is 319.5N. The pessue foce of the obot is 4337N when the obot moving downwad. The viscous foce is 3967N, whee the total foce of the obot is 8909N. The minimum populsion of the popelle the obot need is 8909N to ovecome the esistance. The populsion of the eve popelle is 078N. The esults ae in accodance with those of the efeence[13]. Populsion of the popelle will be diffeent when the velocit of the obot changed. The otate speed of popelle is contolled b the contolle to poduce enough populsion fo the obot, which has established the foundation fo obot contol. t moves in lateal plane when the obot seaching fo the sea cucumbes. The simulation of the obot moving in hoiontal diection is necessa. The obot moving left is simulated thee. The contol domain of the obot is egula heahedon, whose length of side is 10D. Two popelles on opposite sides of the obot wee set moving in hoiontal diection. while the othes wee keep static. The bounda conditions ae the same as the conditions when the obot moving up and down. The pessue clouds ae shown in ig.8. c) Pessue cloud of the obot in outlet diection. igue 8. Pessue cloud of the obot moving left Pa). ig.8a shows that the pessue distibution in the obot is diffeent. ig.8b and ig.8c give the concens that the pessue in the left side of the obot is bigge than the pessue in the ight side. The pessue in ight side is bigge than othe sides ecept fo the obot s left side, which is caused b the wake flow. The maimum pessue appeas in the left side of the shell, the left sufaces of two popelles, which futhe shows that the maimum pessue appeas in the position that fist connected wate. The negative pessue appeas on othe two sides of the obot, which is caused b the fluid flow. The tajecto of the obot is shown in ig.9. igue.9 Tajecto of the obot moving left. ig.9 shows that the tajecto of the obot is staight without othe distubance. The tajecto of the obot is impotant. Onl if the obot moving follows the path pesupposed, can the obot could catch cucumbes. The esistance is calculated in the LUENT. The pessue foce of the obot is 10663N, whee the viscous pessue is 495N. Total esistance of the obot is 11158N. The populsion of eve popelle is 5579N. The otate speed of the popelle is contolled b contolle. a) Oveall pessue cloud of the obot moving left DO / JSSST.a SSN: online, pint

7 USHEN YU et al: DESN AND OTON ANALYSS O ROV ROBOT OR CATCHN SEA CUCUBER V. CONCLUSON This section gives the conclusions and futue diections of eseach. The oveall mechanical stuctue of the ROV sea cucumbe catching obot is intoduced in the pape. The woking pinciples of the obot ae descibed thee. Stuctue of the pivotal mechanism, the intenal assembl and the popelle ae also intoduced. The impotance of the gippe moving mechanism is undelined. The picking pocess of the obot is descibed. The moving analsis of the obot is caied out, which can povide the theoetical basis fo the obot s motion unde wate. The moving equations ae obtained though the analsis. The etenal foce of the obot is calculated though the LUENT fluid analsis softwae, which the populsion of the popelle is deived. Etenal foce of the obot in diffeent velocit can be calculated in the softwae. Pessue cloud also obtained in the LUENT. The maimum pessue appeas in the position of the obot that fist contact with wate. Negative pessue also appeaed. The simulation esults ae the same as those of the theoetical esults. The obot could pick sea cucumbes pecisel in its comple woking envionment. The obot meets the equiement of the social, it has a good application pospects. [6] Wang T, Qi Y, Tang P. Shape Optimal Design of Undewate Robot[J]. achine Tool & Hdaulics, 014,45): [7] Li Y P. Undewate obots advance past pesent and futue[j]. Automation Panoama, 00, 3): [8] Cheng P, He B. nvestigate the Application of ntegated oto Wate-Jet Populso on ROV[J]. uangdong shipbuilding, 014, 3): [9] Ling B, Li S, Zeng J B. Reseach on motion contol of AUV based on otatable thuste[j]. echanical design and anufactuing, 01, 1): [10] Wu N L, Liu J, Xu. AUV thuste aangement and contol simulation eseach[j]. Peiodical of Ocean Univesit of China, 01,44): [11] Bian Y S, ao Z H, Yun C. 6 DO Undewate Vehicle Dnamic Analsis and otion Contol[J], Chinese Jounal of echanical Engineeing, 007,437):87-9. [1] Wu J, Yu, Zhu L L. A hdodnamic model fo a tetheed undewate obot and dnamic analsis of the obot in tuning motion[j]. Jounal of Ship echanics, 011,158): [13] JAN Z J, ZHAN W X, REN L. The odeling and Simulation fo atching of Hull Engine Popelle and Net based on SULNK[J]. Equipment anufactuing Technolog, 013,4):19-1. ACKNOWLEDENTS This wok was financiall suppoted b the National Natual Science oundation of China No ), A Poject of Shandong Povince Highe Educational Science and Technolog Pogam J14LB05), PhD Stat-up und of Shandong Jianhu Univesit XNBS1014). REERENCES [1] an Y, Sun Y S, Wan L. Reseach on the motion contol sstem of DROV[J]. Jounal of Habin Engineeing Univesit, 005,65):6-3. [] Rust C,Asada H H. The eeball ROV: design and contol of a spheical undewate vehicle steeed b an intenal eccentic mass[c]//eee ntenational Confeence on Robotics and Automation.USA: EEE,011: [3] Ais A,Aas S,Rashid Z A. Poblem identification fo undewate emotel opeated vehicle ROV):a case stud[j].pocedia Engineeing,01,41: [4] Cheng W J. Undewate obot[j]. Ocean & ishe, 013,7): [5] Deng Z, Zhu D Q, ang J A. Paamete identification suve of dnamic model fo undewate vehicles[j]. Jounal of Shanghai aitime Univesit, ): DO / JSSST.a SSN: online, pint