The ATRON Self-reconfigurable Robot challenges and future directions

1. The ATRON Self-reconfigurable Robotchallenges and future directions Kasper Støy AdapTronics Group The Maersk Institute for Production Technology University of Southern Denmark www.hydra-robot.dk

2. ATRON Terrestrial Self-Reconfiguration Henrik H. Lund, Esben H. Ostergaard Richard Beck, Lars Dalsgaard, Morten W. Jorgensen Associated: Kristian Kassow, Leonid Paramonov, Kasper Støy, David Christensen, David Brandt, Danny Kyrping Maersk Institute, University of Southern Denmark, Denmark

3. Self-reconfigurable robots

4. ATRON Concept • Key insight: 3D self-reconfiguration can be achieved even-though each module only has one rotational degree of freedom

5. Mechanics : Prototype 0 Concept: Using arms for alignment and screw to connect Produced in 3D printer

6. Mechanics : Prototype 1A • Connector Concept • Two arms parallel to equator • Test of connector • Too weak

7. Mechanics : Prototype 1B • Connector Concept • Trippel Hooks • Dual bars • Test of connector • Prototype broke

8. Mechanics : Final Prototype • Improved main bearing • Improved connector-mechanism

9. Electronics • Two hemispheres • Two sets of main processors • Connector actuation • Hemispheres connected by slipring • One power management processor • Sensors

10. Electronics : Power Supply • Manages recharging • Shares power • Selects best power source • Monitors the organism power supply • Regulates power • 600 batteries sponsored by Danionics

11. Current Mechanics

12. Final Module Design

13. IROS2004 - Demonstration videos • Misalignment correction • Double rotation • Power sharing

14. Concept Demonstations • David Christensen • Meta module demo (ATRON Demo 1) • Jakob Stampe Mikkelsen • Walker

15. Explored control concepts • Local control • Local rules (Esben H. Østergaard) • Gradients and scaffolds (Kasper Støy) • Meta modules (David Christensen) • Centralized control • Planning (David Brandt)

16. Gradients and scaffold

17. Local Rules Esben Østergaard

18. Meta modules David Christensen

19. Conclusion • Control achievements • Control is difficult, but experience gained • ATRON Achievements • Innovative connector design • Innovative lattice structure resulting in • Simplified modules • Easier control…

20. Intermezzo Queen of Denmark admires ATRON module together with the Japanese emperor

21. The Cruel Reality of Self-Reconfigurable Robots Kasper Støy AdapTronics Group The Maersk Institute for Production Technology University of Southern Denmark

22. Vision of self-reconfigurable robots • Robust • Versatile • Cheap

23. The Reality of Self-Reconfigurable Robots • Fragile • Useless • Expensive

24. Robust vs Fragile • Robustness comes from redundancy • If a module fails it can be ejected and other modules can take over • Graceful degradation of performance USC’s ISI

25. Robust vs Fragile • Difficult to detect if a module has failed • Due to motion constraints it is difficult to eject the failed module • Due to weakness of modules it may not be possible to eject the failed module at all

27. Versatile vs Useless • A self-reconfigurable robot can change into any shape needed for the task

28. Versatile vs useless • In practice motion constraints make it difficult to change shape

29. Versatile vs useless • In practice motion constraints make it difficult to change shape

30. Versatile vs useless Start Goal David Brandt

31. Versatile vs useless • Too weak to interact with the world • The ATRON and the MTRAN robots can only lift in the order of a few modules

32. Cheap vs Expensive • ATRON $2000 • MTRAN $3500 • ….

33. The Reality of Self-Reconfigurable Robots • Fragile! • Useless! • Expensive!

34. Challenges of self-reconfigurable robots • How do we • Make robot strength greater than O(1)? • Reduce motion constraints to facilitate easy self-reconfiguration? • Reduce the consequences of module failure? • Reduce module complexity (cost)? …while maintaining our successful results

35. Make robot strength greater than O(1)? • Use module weight to gain leverage (seesaw) • Crystalline/Telecube parallel chains • ….

36. Reduce module complexity (cost)? • ATRON is a step forward, but further - no idea… • Reduce the consequences of module failure? • No idea

37. Reduce motion constraints to facilitate easy self-reconfiguration? • Metamodules • Scaffold • Telecube

38. Hypothesis • The challenges cannot only be addressed at the level of control • The challenges have to be addressed by new innovative hardware design

39. Challenges of self-reconfigurable robots • How do we design the module to • Make robot strength greater than O(1)? • Reduce motion constraints to facilitate easy self-reconfiguration? • Reduce the consequences of module failure? • Reduce module complexity (cost)? …while maintaining our successful results

40. Deformable Modular Robots • All modules are permanently connected in a lattice • Modules can only contract or expand (limited but flexible crystalline module)

41. Concept Demonstration • Physical implementation • Deformatron • Hexatron • Simulation

42. Deformable Modular Robots • Make robot strength greater than O(1)? • Through parallelisms • Reduce motion constraints to facilitate easy self-reconfiguration? • Done • Reduce the consequences of module failure? • Done • Reduce module complexity (cost)? • No connectors …while maintaining our successful results • Shape change within limits • No self-replicating robot

43. Conclusion • Self-reconfigurable robots are facing serious challenges • Increase strength, reduce motion constraints, increase fault tolerance, reduce complexity (price) • Radical new hardware designs needed • Deformable modular robots may be able to sidestep the hardest problems, but at a cost