Yugang Liu & Guangjun Liu

1. Subject: Track–stair Interaction Analysis And Online Tipover Prediction for A Self-reconfigurable Tracked Mobile Robot Climbing Stairs Yugang Liu & Guangjun Liu Author: IEEE/ASME TRANSACTIONS ON MECHATRONICS, VOL. 14, NO. 5, OCTOBER 2009

2. Say before:

3. 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

4. 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

5. Introduction of the RLMA (Ryerson Linkage Mechanism Actuator): dexterous The main features: Simple and dexterous Self-reconfigurable Composing manipulator easily

6. 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

7. General procedure of climbing stairs :

8. Robot-parameters identification :

9. Stair-parameters identification : d0

10. Stair-parameters identification : Ψ0 and h: Sine’s theorem

11. b:

12. Procedure for crawler climbing stairs:

13. 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

14. Nonslipping conditions :

15. Nonslipping with friction : Nonsliping is the most coefficient of static friction.

16. Grousers hooking: Nonsliping

17. First two steps: Slippage and interactive motion analysis :

18. Step 3 slippage: Ceil function gives the smallest integer lager than or equal to x

19. 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

20. kinematic analysis and step classification : The coordinate system:

21. Step 1----

22. Step 2---- θ = θs

23. Step 3----

24. Step4--- 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.

25. 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

26. Track-stair interactive force analysis : Step 0 It can be treated as moving on a inclining terrain. 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.

27. Step 1 It can be treated as pull slip when one grouser has hooking the tread of the first stair firmly.

28. Track-stair interactive force analysis : Step 2 It has two kinds of situation. Case 1: If one point contacts with stairs. N1, Nd, F1, Fp, Fd are calculated in the same way as step 1. Case2: If two point contacts with stairs.

29. Step 3 It can be treated as moving on a inclining terrain and the supporting points are only three, like as step 0.

30. 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.

31. 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.

32. Thank you!