Track–Stair Interaction Analysis and Online Tipover Prediction for a Self-Reconfigurable Tracked Mobile Robot Climbing Stairs

8/9/2019 TrackStair Interaction Analysis and Online Tipover Prediction for a Self-Reconfigurable Tracked Mobile Robot Climbing Stairs

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Track Stair Interaction Analysis and

Online TipoverPrediction for a Self-ReconfigurableTracked Mobile

Robot Climbing Stairs

NYUST ME

Robotic Embedded Systems Lab


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Provenance :Yugang Liu and Guangjun Liu , Senior Member,IEEE Index Terms :Stair climbing,tipover prediction,Tracked mobile robot,track stair interactions .


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Wh y track


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floatation and traction t h an t h e w h eeled ones- explosive ordnance disposing,

searc h ing,rescuing,mining,logging,

farming,eart h moving,and planetary exploring among ot h ers.


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Traditionally, most of t h e tracked ve h icleswere designed to be bulky and h eavy to suitfor field operations on natural terrain

As one of t h e most omnipresent artificialenvironments, stairway represents a serious

ch allenge to robotics, w h ich h as to beaddressed for robots to operate efficiently inurban environ


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Related Research


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,

feedback system automatic h eading control

tipover stability criteria

(zero moment point met h od ,t h e force-angle measure ,

and t h e supporting force criterion)


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A real-time tipover prevention algorit h m isdeveloped for redundant non h olonomic

mobile modular manipulators by onlineadjusting self-motions, so t h at t h e primarytask at t h e end-effector can be unaffected .

An online tipover prediction algorit h m isproposed and t h e robot is controlled to returnback to t h e initial configuration in case of tipover instability.


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Tipover stability is studied wit h out consideringtrack stair interactions

In t h is paper, t h e track stair interactions,including slippage of a self-reconfigurabletracked mobile robot (SRTMR) in stair climbing

are analyzed systematically.


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SRTMR Planetary w h eelsDriving w h eelsFlippers

Grousers

Supporting w h eelsCh assis

Tracks


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RLMA consists of a c h assis, two tracks, twodriving w h eels, two supporting w h eels, andtwo planetary w h eels


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Th e two driving w h eels can be controlledindependently to realize steering


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flippers ; flippers ,pitc h motor


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if 0 < p < , t h e flippers and t h e planetary

wh

eels will be raisedp = 0 p = flippers , RLMA,

flippers -90< p


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General Procedure for RLMA Climbing Stairs


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Step 1: Climbing onto the stairs and setting back the flippers.


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Step 2: Climbing onto the stairs withthe flippers in the back.


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Step 3: Going on the nose line.


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Step 4: Landing on the top floor.


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Stair-Parameters Identification


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From Fig. ,t h e trajectory of planetary w h eelcenters is an ellipse, and t h e flippers lengt h can be determined by


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wh ere Lp (0) and Lp ( /2) can be determined

by th

e track length

Lt and the wheel radius r by


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In Fig. ,t h e incline angle of t h e track segmentbetween t h e supporting and planetary w h eels

0 can be determined by applying t h e sine sth eorem to t h e triangle OmSP as follows:


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Furt h ermore, t h e stair h eig h t can becalculated

hg is the grousers height r is the radius of the wheels


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In Fig,t h e difference between t h e incline angleof t h e stairs and t h at of t h e c h assis can bedetermined by applying sine s t h eorem toOmSP as follows:


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Furt h ermore, t h e tread widt h can becalculated as follows:

W ith th e stair h eig h t h and tread width bidentified, the incline angle of t h e stairs can beeasily determined as follows


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SLIPPAGE AND TRACK STAIR

INTERACTIVE MOTIONS


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Th e sufficient and necessary condition fornonslipping can be given by fs (F1/N1 ) fs ,where fs is the coefficient of static friction,


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If fs < cot s ,


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If fs < tan s


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Slippage and interactive motion analysis for

th

e first two steps

Documents

Track–Stair Interaction Analysis and Online Tipover Prediction for a Self-Reconfigurable Tracked Mobile Robot Climbing Stairs