Yugang Liu & Guangjun Liu
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Transcript of Yugang Liu & Guangjun Liu
Track–stair Interaction Analysis And Online Tipover Prediction
for A Self-reconfigurable Tracked Mobile Robot Climbing Stairs
Yugang Liu & Guangjun Liu
Subject:
Author:
IEEE/ASME TRANSACTIONS ON MECHATRONICS, VOL. 14, NO. 5, OCTOBER 2009
Say before:
Main content:
•1. Introduction of the crawler•2. Procedure for crawler climbing stairs•3. Slippage and interactive motion
analysis•4. Kinematic analysis and step
classification•5. Track-stair interactive force analysis•6. Conclusion
Main content:
•1. Introduction of the crawler•2. Procedure for crawler climbing stairs•3. Slippage and interactive motion
analysis•4. Kinematic analysis and step
classification•5. Track-stair interactive force analysis•6. Conclusion
Introduction of the RLMA (Ryerson Linkage Mechanism Actuator):
The main features:1. Simple and dexterous2. Self-reconfigurable3. Composing manipulator easily
dexterous
Main content:
•1. Introduction of the crawler•2. Procedure for crawler climbing stairs•3. Slippage and interactive motion
analysis•4. Kinematic analysis and step
classification•5. Track-stair interactive force analysis•6. Conclusion
General procedure of climbing stairs :
( 2 ) / 2tL r L
(0) ( 2 ) / 2 / 2tLp L r L
Robot-parameters identification :
Stair-parameters identification :
d0
Ψ0 and h:
Stair-parameters identification :
Sine’s theorem
b:
Procedure for crawler climbing stairs:
Main content:
•1. Introduction of the crawler•2. Procedure for crawler climbing stairs•3. Slippage and interactive motion
analysis•4. Kinematic analysis and step
classification•5. Track-stair interactive force analysis•6. Conclusion
Nonslipping conditions :
Nonslipping with friction :Nonslipin
g
1 1 1s sf N F f N
is the most coefficient of static friction.
sf
Grousers hooking:Nonslipin
g
Slippage and interactive motion analysis :First two steps:
Step 3 slippage:
x Ceil functiongives the smallest integer lager than or equal to x
2 2 2 2( / ) ( / )rem g gk b h d b h d
Main content:
•1. Introduction of the crawler•2. Procedure for crawler climbing stairs•3. Slippage and interactive motion
analysis•4. Kinematic analysis and step
classification•5. Track-stair interactive force analysis•6. Conclusion
kinematic analysis and step classification :
The coordinate system:
Step 1----
mx
mz
2L
, ,m mx z
Step 2----
θ = θs
, ,m mx z
Step 3---- , ,m mx z
Step4--- , ,m mx z
Landing process consists of two parts:Subprocess 1. the pitch joint rotates anticlockwise;Subprocess 2. the driving wheels continue to drive the robot until it plunges onto the upper floor.
Main content:
•1. Introduction of the crawler•2. Procedure for crawler climbing stairs•3. Slippage and interactive motion
analysis•4. Kinematic analysis and step
classification•5. Track-stair interactive force analysis•6. Conclusion
Track-stair interactive force analysis :Step 0
Quoted from Y. Liu and G. Liu, “Kinematics and interaction analysis for tracked mobile manipulators,” in Proc. IEEE/RSJ Int. Conf. Intell. Robot. Syst., San Diego, CA, USA, Oct. 2007, pp. 267–272.
It can be treated as movingon a inclining terrain.
Step 1It can be treated as pull slip when one grouser has hooking the tread of the first stair firmly.
Track-stair interactive force analysis :Step 2
Case 1:If one point contacts with stairs.N1, Nd, F1, Fp, Fd are calculated in the same way as step 1.
It has two kinds of situation.
Case2:If two point contacts with stairs.
Step 3
It can be treated as movingon a inclining terrain and the supporting points are only three, like as step 0.
Step 4
The supporting forces N1 and N2 for step 4 can be calculated in the same way as that in step 3, but replaced r with r+(L/2)sin(θs- θ) and k with ns-1.
Conclusion:
• In this paper, track–stair interactions were analyzed systematically and conditions for firm-hooking and nonslipping were presented for a self-reconfigurable tracked mobile robot climbing stairs.
• The stair-climbing process is divided into four steps, with consideration of the track–stair interactions.
• As the first attempt to analyze track–stair interactions, this paper has laid a solid foundation for further investigations on this important topic.
Thank you!