1 RiSE: First Steps up the Wall Southwest Research Institute (SwRI), March 3-12, 2005 Clark Haynes and Sarjoun Skaff March 22, 2005 Center for the Foundation of Robotics

2 RiSE: First Steps up the Wall

3 Wall Climbing Challenges Minimally Invasive Discreet Low Power Multiple Surfaces Dynamic Climbing

4 RiSE: First Steps up the Wall Biologically Inspired Answer Six leg - Actuated motion - Passive compliance Collection of feet - Sticky for smooth surfaces - Clawed for rough surfaces

5 RiSE: First Steps up the WallRiSE Robot in Scansorial Environments - First prototype to climb hard and soft surfaces - Develop intuition to improve performance Dactyl on carpet Sticky foot on Plexiglass

6 RiSE: First Steps up the Wall Field Trip Behavior Generation Climbing SurfacesOutline System Description

7 RiSE: First Steps up the Wall Mechanical Platform

8 RiSE: First Steps up the Wall Mechanical Platform

9 RiSE: First Steps up the Wall Climbing Carpet at 90° Feet Type Dactyl Gait Type Tripod Challenge Difficult Detachment

10 RiSE: First Steps up the Wall Climbing Cork at 90° Challenges - Fragile material  Careful attachment - Failed attachment  Immediate fall - Attachment sensitive to spine sharpness Feet Type Spiny Gait Type Tripod

11 RiSE: First Steps up the Wall Climbing PlexiGlass at 55° Feet Type Lamellarized Polyurethane Gait Type Tetrapod Challenges - Large Feet  High C.O.G. - Foot contact area depends on weight distribution - Vibrations limits foot contact area

12 RiSE: First Steps up the WallWalking Feet Type Rubber Gait Type Tripod Challenges - Inadequate passive compliance - Small gear ratio  Low speed

13 RiSE: First Steps up the Wall Gait Design - 1 st DOF: 4-bar kinematics, “Beta Curve” - 2 nd DOF: Wing joint - Beta x Wing  2D Manifold β = FKin( Θ) π2π

14 RiSE: First Steps up the Wall Geometric Considerations - Beta Curve chosen to perform both running and climbing - Gaits are piecewise linear trajectories upon 2D Manifold - 4 components to a generic climbing gait: “Attachment”, “Stance”, “Detachment”, “Flight” PlexiglassWalking

15 RiSE: First Steps up the Wall Trajectory Variations - Surface properties dictate climbing trajectories - Pull-in forces, attachment, detachment vary PlexiglassCarpetCork

16 RiSE: First Steps up the Wall Fore-Aft Differentiation Carpet Leg 1Carpet Leg 3 Push-Pull relationship between back and front legs helps to prevent pitchback of robot

17 RiSE: First Steps up the Wall Forward vs. Backward Gaits Carpet ForwardCarpet Backward - Running gait in reverse doesn’t work! - Attachment requires pull-in, detachment needs straight exit from surface

18 RiSE: First Steps up the Wall Leg Phasing and Duty Factors Tripod Rippled Tripod Tetrapod Pentapod

19 RiSE: First Steps up the Wall Carpet Mobility Challenge: - Maneuver robot through obstacle course on carpeted surface - Turning with claws attached to wall - Forward vs. Backward gaits - Tripod vs. Pentapod for speed, stability

20 RiSE: First Steps up the Wall Tripod Turning Tripod 1Tripod 2 50%

21 RiSE: First Steps up the Wall Tripod Turning Tripod 1aTripod 2Tripod 1b 50%25%

22 RiSE: First Steps up the Wall Ripple/Tetrapod Turning Set 1Set 2Set 3 33%

23 RiSE: First Steps up the Wall Transitions - Related Gaits Forward TripodBackward Tripod

24 RiSE: First Steps up the Wall Transitions – Unrelated Gaits TripodPentapod

25 RiSE: First Steps up the Wall SwRI Test Facility

26 RiSE: First Steps up the Wall Carpet Mobility

27 RiSE: First Steps up the Wall Hybrid Foot Configuration

28 RiSE: First Steps up the Wall Tree Climbing

29 RiSE: First Steps up the Wall Clinging to Surfaces

30 RiSE: First Steps up the Wall On-site Foot Development

31 RiSE: First Steps up the WallBrick

32 RiSE: First Steps up the WallWalking

33 RiSE: First Steps up the Wall Lessons Learned PlexiGlass - Adhesion deteriorates with dirt  Climbing 0.5m is different from climbing 3m - Foot morphology - Large feet  More adhesion - Small Feet  C.O.G closer to surface  Steeper climbs Cork - Fragile surfaces  Smooth attachment - Re-Attach to avoid fall  Detect attachment failure Carpet - Difficult detachment  Detect detachment failure, Microspines

34 RiSE: First Steps up the Wall Looking Ahead - Drop the gears - Actuate the tail - Climb faster - Climb outdoor surfaces - Multi-purpose feet - Horizontal ↔ Vertical - Add Feedback

35 RiSE: First Steps up the Wall K. Autumn M. Buehler M. Cutkosky R. Fearing R. J. Full D. E. Koditschek A. A. Rizzi Clark Haynes Sarjoun Skaff Uluç Saranli Lewis & Clark Boston Dynamics Stanford UC Berkeley U Penn Carnegie MellonCredits

36 RiSE: First Steps up the Wall

37 RiSE: First Steps up the Wall FTFT Mg MTMT ATAT TNTN FNFN MNMN ANAN D L Assume Normal Force Tangential Force Surface Loads Tangential Loading Normal Loading Assume equal weight distribution Normal Force Max - Fully Attached - Partially Attached Tangential Force Max - Fully Attached - Partially Attached