Let's build modular robots!
- 1. Let's build a modular snake robot! Dr. Juan González-Gómez July-2nd-2013 1
- 2. Let's build a modular snake robot! Agenda 1. Introduction 2. Modules 3. Locomotion in 1D 4. Locomotion in 2D 2
- 3. Modular robots One module to rule them all!! Multiple configurations 3
- 4. Morphology 1D topology 2D topology 3D topology Snake robots Pitch-pitch Yaw-yaw Pitch-yaw 4
- 5. Controller How to generate the snake motion? Bio-inspired Classic ● ● ● Mathematical models Inverse kinematics Depend on the morphology ● ● Nature imitation Central pattern generators (CPG) CPG CPG CPG 5
- 6. Controller for snake robots ● Replace the CPGs by sinusoidal oscillators CPG ● CPG CPG Sinusoidal oscillators: φ i (t )= Ai sin( 2π t + ψi)+ Oi T Advantages: ● Very few resources are needed for their implementation 6
- 7. Software architecture Locomotion layer Oscillator layer Servo layer Pw m 7
- 9. Let's build a modular snake robot! Agenda 1. Introduction 2. Modules 3. Locomotion in 1D 4. Locomotion in 2D 9
- 10. Y1 modules family ● One degree of freedom ● Easy to build ● Servo: Futaba 3003 ● Size: 52x52x72mm ● Types of connection Open source Y1 Repy1 MY1 10
- 11. REPYZ modules ● The latest version ● 3D Printed ● Easy to clone ● Easy to modify ● Designed in Openscad ● Open source 11
- 12. New age: 3D printing! You can convert ideas into real objects!! ● EASY ● FAST ● CHEAP 12
- 13. RepRap: Open source 3D printers Demo 13
- 14. REPYZ (II) ● Freecad Module in Freecad (an open source CAD tool) 14
- 15. REPYZ (III) ● Designed in Openscad (Another open source tool) ● Openscad The module is code! Like programming! 15
- 16. REPYZ. Assembling (I) ● REPYZ exploded view 16
- 17. REPYZ. Assembling (II) ● REPYZ: Bill of materials 17
- 18. REPYZ. Assembling (III) ● Embed four M3 nuts 18
- 19. REPYZ. Assembling (IV) ● Change the servo lower cover by the new one 19
- 20. REPYZ. Assembling (VI) ● Screw the servo to the body part 20
- 21. REPYZ. Assembling (VI) ● Prepare the module head 21
- 22. REPYZ. Assembling (VII) ● Join the body and the head 22
- 23. REPYZ. Assembling (VIII) ● Add the 608 bearing 23
- 24. REPYZ. Assembling (XI) ● Tighten the servo horn 24
- 25. REPYZ (X) ● The module is ready! 25
- 26. Oscillations (I) TASK: ● ● ● Insert the battery packs into the holders Screws the electronics with 20mm in length spacers Connect one servo to the SERVO 2 connector 26
- 27. Module oscillation Demo φ (t )= Asin( Bending angle 2π t +Φ)+ O T Sinusoidal oscillator Parameters: ● Amplitude: A ● Period: T ● Offset: O 27
- 28. Oscillation of two modules φ 1 (t )= A sin( 2π + Φ0 ) T φ 2 (t )= A sin( Demo 2π +Δ Φ +Φ 0 ) T ΔΦ New parameter: ● Phase difference: ΔΦ It determines how a module oscillates in relation to other 28
- 29. Experiment I: the wave Demo TASK: ● ● ● ● Create “the wave” using 9 REPYZ modules Amplitude, offset and period are fixed See what happens for different phase differences Fundamental equation: 360 Δ Φ= k M ● ● ● Degrees ● ● K number of waves M number of modules M = 9, k = 1 ===> 40 M = 9, k = 2 ===> 80 M = 9, k = 3 ===> 120 29
- 30. Let's build a modular snake robot! Agenda 1. Introduction 2. Modules 3. Locomotion in 1D 4. Locomotion in 2D 30
- 31. Control model 31
- 32. Minimal configuration TASK: ● ● ● Build 3 minimal configuration Each one consist of 2 modules Test the locomotion for different oscillator parameters 32
- 33. 3 module configuration TASK: ● ● Build 3 configurations composed of 3 modules each Test the locomotion for different oscillator parameters 33
- 34. 6 modules configuration TASK: ● ● Build 1 configurations composed of 6 modules Test the locomotion for different oscillator parameters 34
- 35. 9 modules configuration TASK: ● ● Build 1 configurations composed of 9 modules Test the locomotion for different oscillator parameters 35
- 36. Let's build a modular snake robot! Agenda 1. Introduction 2. Modules 3. Locomotion in 1D 4. Locomotion in 2D 36
- 37. Control model 37
- 38. Locomotion gaits Straight Av =40, Ah=0 v =120 Sideways Av = Ah40 vh =90, v=0 Av = Ah60 turning Rotating Av =40, Ah=0 Oh =30, v =120 Rolling Av =10, Ah=40 vh =90, v=180 vh =90, v=0 38
- 39. Minimal configuration TASK: ● ● Build 3 PYP configurations composed of 3 modules Test the different locomotion gaits 39
- 40. 6 module configuration TASK: ● ● Build 1 pith-yaw configuration composed of 6 modules Test the different locomotion gaits 40
- 41. Locomotion gaits Sidewinding Straight Rotating v 0, k v =k h , vh=90 k h=1 v =40 , k v =2 h =0 Rolling Turning v 0,k v=2kh , vh =0 v 0, vh =90 v =40 , k v =3 h ≠0 41
- 42. Let's build a modular snake robot! Dr. Juan González-Gómez July-2nd-2013 42