1. ICT 1 MODULAR SNAKE ROBOT 3D MODELLING, IMPLEMENTATION AND CONTROL Pål Liljebäck – Øyvind Stavdahl – Kristin Y. Pettersen

2. ICT 2 Outline Applications of snake robots Mathematical modelling Motion planning and control Simulation results Development of Anna Konda Future work

3. ICT 3 What is a snake robot? A robot that can mimic motion patterns of biological snakes A serial connection of mechanical joints and actuators that can locomote through co-ordinated movements of the joints

4. ICT 4 Fire fighting Effective rescue, situation analysis and intervention Applications of snake robots

5. ICT 5 Maintenance/intervention in hostile environments Subsea operations Applications of snake robots

6. ICT 6 Explosion prevention Preventive efforts in environments with a high risk of explosion Applications of snake robots

7. ICT 7 Applications of snake robots Search & Rescue in hostile/challenging environments

8. ICT 8 Our snake robots Pneumatic snake robot, 2004 Water hydraulic snake robot, 2005

9. ICT 9 Mathematical modelling

10. ICT 10 Kinematics The relationship between joint angles and the position of each joint module The Denavit-Hartenberg convention  homogeneous transformation matrixes Mathematical modelling

11. ICT 11 External forces on each joint module Normal forces modelled as a mass-spring-damper system Mathematical modelling

12. ICT 12 External forces on each joint module Friction forces are partitioned into a transversal part (with respect to the snake body) and a longitudinal part A combination of viscous and coulomb friction Mathematical modelling

13. ICT 13 Dynamics The relationship between forces/torques and resulting velocities and accelerations The Newton-Euler formulation Mathematical modelling

14. ICT 14 A general expression for the desired joint angles was developed Motion planning and control Horizontal wave Vertical wave Desired angle Amplitude Phase difference between joints Angular frequency Phase difference between the two waves Angular offset

15. ICT 15 The brain of the snake robot computes reference angles for each joint PD-controller in each joint module Motion planning and control

16. ICT 16 Simulation of the snake robot Mathematical model and control strategy implemented in Matlab and Simulink Visualization of the simulation results with the VR Toolbox in Matlab

17. ICT 17 Simulation results Lateral undulation Directional control with the parameter,

18. ICT 18 Lateral undulation Directional control with the parameter, Simulation results

19. ICT 19 Simulation results Sidewinding Directional control with the parameter,

20. ICT 20 Sidewinding Directional control with the parameter, Simulation results

21. ICT 21 Requirements: Snake robot consisting of 10 joint modules 2 DOF joints Water hydraulic actuation (100 bar system pressure) in order to demonstrate the fire-fighting application Constructing the robot posed a great challenge: Small water hydraulic valves did not exist on the market The valves had to be custom-built Development of Anna Konda

22. ICT 22 Valves Manufactured at a workshop in Trondheim Development of Anna Konda

23. ICT 23 Cylinders Manufactured at a workshop in Trondheim Development of Anna Konda

24. ICT 24 Electronic control system Custom-built printed circuit boards Wireless communication with the robot Development of Anna Konda

25. ICT 25 Anna Konda The first water hydraulic snake robot in the world The biggest and strongest snake robot in the world

26. ICT 26 Sidewinding Anna Konda

27. ICT 27 Anna Konda Lifting head and spraying water

28. ICT 28 Future work Future work on Anna Konda: New and improved gait patterns Skin structure to cover the robot Integration of contact force sensors Continued research through doctoral thesis at NTNU initiated spring 2004 Continued research through master’s theses at NTNU SINTEF is currently searching for collaborating partners in order to aid further development