Design and Analysis of Landing Gear Mechanic Structure for the Mine Rescue Carrier Robot

Transcription

1 Sensors & Transducers 214 by IFSA Publshng, S. L. Desgn and Analyss of Landng Gear Mechanc Structure for the Mne Rescue Carrer Robot We Juan, Wu Ja-Long X an Unversty of Scence and Technology, X an 7154, Chna Tel.: E-mal: wej@xust.edu.cn Receved: 9 Aprl 214 /Accepted: 3 May 214 /Publshed: 3 June 214 Abstract: The landng gear s used as a channel for the secondary detectng robot to leave and return the frst carrer robot n the coal mne rescue robot system. The planar lnkage mechansm, whch s composed of offset rocker-slder mechansm and double-rocker mechansm, s desgned accordng to the functon and workng prncple of the landng gear. It could realze the 12 rotaton of the flap wth a motor drvng the slder. The sze calculaton of the planar lnkage mechansm s completed accordng to ts workspace. The geometrc modelng of the landng gear s made n the SoldWorks, and the basc Knematc analyss s carred out by the smulaton module of Moton. And the movement rule about angular dsplacement and angular velocty of the lnkage mechansm could be obtaned under gven nput condton, whch could verfy the system s feasblty. It provdes a theoretcal bass for the structure desgn and engneerng applcaton of lnkage mechansm and an applyng bass for the coal mne rescue robot. Copyrght 214 IFSA Publshng, S. L. Keywords: Mne rescue robot, Landng gear, Planar lnkage mechansm, SoldWorks moton. 1. Introducton Mne rescue two-stage robot system s used n the status that mne accdents occur n workng faces away from the mne entrance, t adopts two-stage robot structure [1], the frst orbtal-carrer robot and the secondary crawler detectng robot. As the secondary complex-crawler robot moves slowly, whch needs a long tme to drve to the accdent ste, t would mss the golden perod for rescue, so we use the frst-stage carrer robot, drvng on the orbt wth a faster speed, to reduce the drvng tme. After a mne accdent, the frst-stage carrer robot [2] carres the second-stage detectng robot [3] along the underground transport orbt movng fast to the place where the accdent happened. If the frst-stage robot s obstructed, the second-stage would get off and keep on movng to the accdent ste, and t would get back wth ts work done. And the role of the landng gear s to form a road slope for the second-stage robot to get off and on. The basc machne of the carrer robot ncludng the car body, drvng mechansm, travellng mechansm, brakng mechansm, buffer mechansm and landng gear [4], as shown n Fg. 1, ts man functon s to guarantee the safe runnng of the carrer along the orbt. In the desgn of landng gear, the planar lnkage mechansm would be used to complete part of the complex movement accordng to ts advantages and wldly use n engneerng practce, such as usng lower pars, not easy to wear, easy to process wth low cost and could acheve a varety of complex movement curves and movement rules

2 Fg. 1. The structure of secondary carrer robot. 2. Desgn of the Planar Sx Bar Mechansm The planar sx bar mechansm [5, 6] s composed of the offset rocker-slder mechansm and doublerocker mechansm, the functon of the frst part s to transform the lnear moton of the rack to the rotaton moton of a bar, and the functon of the double-rocker mechansm s to amplfy the rotaton angle and to make sure the 12 rotaton moton of the flap. a = mm S = mm, (3) ϕ = ϕ = For the poston 2, the angle between the bar a and b s 32.27, far away from the dead zone, and the operatng requrement could be satsfed The Sze Calculaton of the Offset Rocker Slder Mechansm The offset rocker-slder mechansm s composed of slder, bar a and bar b. ts target s to turn bar b over 6 n a clockwse drecton. The slder s the nput whle the bar b s the output, and the lnear moton of the slder would translated to the rotaton moton of bar b. The extreme postons [7] are shown n Fg. 2 and Fg. 3 respectvely. The equaton for the extreme poston 1: asnϕ + e= bsnψ acosϕ bcosψ = S, (1) Fg. 2. Poston 1 of the offset rocker slder mechansm. The equaton for the extreme poston 2: asnϕ + e= bsnψ, (2) acosϕ bcosψ = S Accordng to the overall structural sze of the landng gear and carrer robot, defne: S = 8 mm, e= 15 mm, b= 5 mm, ψ = 15, ψ = 75. Smultaneous the equaton could obtan: Fg. 3. Poston 2 of the offset rocker slder mechansm. 236

3 2.2. Sze Calculaton of the Double Rocker Mechansm The double rocker mechansm s composed of bar l 1, l 2, l 3 and l 4. It s target s to rotate the bar l 3, the flap, 12 n the clockwse drecton, the rod l 1 s the nput wth a rotaton of 6 degrees and the bar l 3 s the output wth a rotaton of 12. The extreme postons [8] of ths mechansm are shown n Fg. 4 and Fg. 5 respectvely. 2) The equaton for the extreme poston 2: l1snϕ l2snδ = l3snψ, (7) l1cosϕ + l2cosδ = l4 + l3cosψ After the elmnaton of δ, we could obtan: l = ( l snϕ + l sn ψ ) + ( l + l cosψ l cos ψ ), (8) Accordng to the overall structural sze of the landng gear and carrer robot, defne: l3 = 5 mm, l 4 = 58 mm, ψ = 3, ϕ = 25, ϕ = ϕ + 6, Smultaneous the equaton could obtan: l1 = 952 mm l2 = mm, (9) δ = 42.5 δ1 =77.3 Fg. 4. Extreme poston 1 of the double rocker mechansm. For poston 2, the angle between the rod a and b s 17.3 and the operatng requrement could be satsfed. The bar b of offset rocker slder mechansm and the bar l 1 of double rocker mechansm would rotate around the same pont, the angle between them s 5, and the connectng bar s shown n Fg. 6. Fg. 5. Extreme Poston 2 of the double rocker mechansm. Components could be expressed as vectors, and accordng to the closed vector graphcs, the followng vector equaton could be obtaned: l1+ l2 = l3+ l4, (4) Project to the X axs and Y axs, we could obtan: 1) The equaton for the extreme poston 1: l1snϕ l2snδ = l3, (5) l1cosϕ + l2cosδ = l4 After the elmnaton of δ, we could obtan: l = ( l sn ϕ l ) + ( l l cos ϕ ), (6) Fg. 6. Connectng bar The Structural Characterstcs of the Landng Gear All of the structural szes of the combned mechansm could be obtaned accordng to the dmenson value we calculated, ts CAD drawng of the two extreme postons are shown n Fg. 7 and Fg. 8. In poston 1, the rack s on the left sde whle the flap s perpendcular to the ground, and n poston 2, the rack s on the rght wth a lnear moton whle the flap rotates 12 n the clockwse drecton. 237

4 1 Car body, 2 Gear shaft, 3 Prsmatc par, 4 Rack, 5, 6, 7 bar, 8, 1, 11 Rotaton par, 9 flap. Fg. 7. Poston 1 of the landng gear. Fg. 9. The model of landng gear n SoldWorks Moton Smulaton and Analyss In SoldWorks Moton, all components are regarded as the deal rgd body, whch means the deformaton wll not occurred nsde of each bar and between the bars n smulaton process. Connectng formats and constrants accordng to the movement characterstc of the mechansm should be approprate, that s because those elements have a vtal mportance to the vrtual assemble and moton smulaton [9]. Consderng the speed change of the motor at the startng and stoppng moment and n order to avod the collson between the car body and flap, an optmzed velocty curve of the motor s gven as shown n the Fg. 1. Fg. 8. Poston 2 of landng gear. 3. The Knematc Analyss of the Landng Gear By usng vrtual prototype smulaton tools SoldWorks Moton, Knematcs and dynamcs smulaton analyss of complex mechansms can be done, and moton parameters could be obtaned, such as dsplacement, velocty, acceleraton, force and reacton force, etc. It s provded opportuntes to do Knematc analyss work wthout physcal prototype manufactured. Fg. 1. Velocty-tme curve of the rack Constructon of Three-dmensonal Model In SoldWorks, all components of the landng gear should be modeled and assembled accordng to the actual condtons; the assembly model s shown n Fg. 9. The rack s the nput whle the flap 7 s the output, the lnear moton of the rack could be transformed to the rotatonal moton of the flap. In the moton smulaton analyss, set the moton opton as the functons, and the equaton of the velocty s gven as n equaton y = ( x < 2) 2, y = 95 (2 x < 8) 95 y = ( x 6) + 95(6 x 8) 2 (1) 238

5 The speed of the rack, the vce 3, would be ncrease to 95 mm/s from mm/s on a constant acceleraton, and t would be decrease to mm/s on a constant acceleraton after a constant movement of 4 seconds. After the calculaton, the angular dsplacement-tme curve of the flap could be obtaned as shown n Fg. 11, and the angular speed-tme curve of the flap, revolute par 8, could also be obtaned as shown n Fg. 12. The rotaton angle of the flap s 12, and the angular speed would be ncreased from deg/s gradually and reach the maxmum at about 6 s, then t would be decreased gradually and reached deg/s at 8 s. The collson between the car body and the flap at the extreme postons would be avoded and the expected goals could be acheved better under ths speed curve. 24 deg/s whle the maxmum of the bar 5 s 11 deg/s. we could fnd that the expected target could be obtaned well wth the planar sx rod mechansm from those curves. Fg. 13. Angular dsplacement-tme curve of the bar 6. Fg. 11. Angular dsplacement-tme curve of the flap. Fg. 14. Angular velocty-tme curve of the bar Concluson Fg. 12. Angular velocty-tme curve of the flap. The angular dsplacement-tme and angular speed-tme curves of the bar 6, the revolute par 1 and 11, could also be obtaned as shown n Fg. 13 and Fg. 14. The rotaton angle s 6, ts angular speed-tme curve s smlar to the curve of flap wth a dfferent maxmum, and the maxmum of the flap s The role of the landng gear n the carrer s to provde a pass way for the secondary detectng robot to leave and return, t requres not only strong operaton relablty, runnng stablty, a certan carryng ablty but also the smple structure, easy to control and autonomous control. 1) The structure and geometry szes of the landng gear mechansm were determned after the calculaton of extreme postons of the offset slder rocker mechansm and double rocker mechansm under the suffcent analyss of the functonal requrements of the landng gear. 2) Moton Smulaton of the landng gear were carred out by usng vrtual prototype smulaton tools, SoldWorks Moton, the angular dsplacementtme and angular velocty-tme curves of the man components were obtaned and the feasblty of the mechansm were verfed. In order to avod the 239

6 collsons between the flap and car body n extreme postons, the optmzed nput velocty curve were offered. Acknowledgements The project s supported by the Natural Scence Foundaton of Chna, No and No References [1]. Juan We, Hongwe Ma, Study on mne rescue robot system, n Proceedngs of the 2 nd Internatonal Conference on Intellgent Robotcs and Applcatons, Vol. 2489, December 29, pp [2]. We Juan, Ma Hongwe, Parametrc optmzaton desgn on mne carrer robot, Advanced Materals Research, Vol. 346, 212, pp [3]. We Juan, Ma Hongwe, Knetc characterstcs analyss and smulaton research on carrer robot, Advanced Materals Research, Vol. 346, 212, pp [4]. We Juan, Ja Guangl, Ma Hongwe, Smulaton analyss of the vrtual prototypng of a recue robot, Mechancal Scence and Technology for Aerospace Engneerng, Vol. 27, Issue 11, 28, pp [5]. Yang Yan, Research on knematc smulaton of RRR-RRP planar sx bar mechansm system, Journal of Nanchang Hangkong Unversty (Natural Scences), Vol. 24, No. 4, 21, pp [6]. Qu Xuquan, Dynamc smulaton of planar lnkage based on MATLAB/Smulnk, Harbn Insttute of Technology Press, Harbn, 27. [7]. Hua Danan, Hua Zhhong, Lnkage desgn and applcaton nnovaton, Chna Machne Press, 28. [8]. Zhang Xaolng, Shen Shaohua, Practcal mechansm desgn and analyss, Behang Unversty Press, 21. [9]. L Dale, Dng Tantao, Cheng Janmn, Moton analyss for space swngng nsttuton based on SoldWorks moton, Manufacturng Automaton, Vol. 33, Issue 22, 211, pp Copyrght, Internatonal Frequency Sensor Assocaton (IFSA) Publshng, S. L. All rghts reserved. ( 24