110 likes | 217 Views
Climbing Feet for RiSE. June 14, 2004 Miguel Piedrahita BDML. Overview of Future Climbing Foot Development. Long-term goals: Sufficient shear and normal forces for dynamic vertical climbing, on a variety of surfaces Effective attachment and detachment
E N D
Climbing Feet for RiSE June 14, 2004 Miguel Piedrahita BDML
Overview of Future Climbing Foot Development Long-term goals: • Sufficient shear and normal forces for dynamic vertical climbing, on a variety of surfaces • Effective attachment and detachment • Integration of dry adhesives with spines and perhaps other mechanisms • Integrated sensing Short-term needs: • We need to demonstrate effective climbing with the RiSE platform for key dates (August, October)!
What do we need for success in Aug/Oct? • Video which shows progress towards vertical climbing on a variety of surfaces • Show clear integration path of innovations from demonstration platform
Do we need adhesion? • Based on location of CM and rear feet, we can stand on 58 deg slope without adhesion. • Could we climb on a slightly flatter slope? • Still need lots of shear force! • Is that good enough for Aug/Oct? 58.0 deg
Specialized Feet for each surface? • Easiest way to achieve good climbing on these three types of surfaces is to design a separate foot for each surface! • Soft surface: Larger, stiffer claws and spines • Rough surface: Delicate, individually sprung claws and spines • Smooth surface: PSA and friction pads • Will RiSE researchers and DARPA buy into this approach? • Not a very elegant solution, will lead to integration challenges in the future.
Single Climbing Foot for all Surfaces? Requirements: • Foot-level Compliance • High yaw compliance to deal with changing foot angle during stroke due to 4-bar kinematics • Some pitch & roll compliance to conform to surface • Effectively combine several adhesion/shear mechanisms OR • Develop a single adhesion/shear mechanism which will work on all surfaces
Combine several mechanisms? • Retractable spines/claws • Push/pull cables, SMA • Spines/claws with changing compliance • Full-foot pivoting to engage different foot surfaces • R/C servo or SMA actuation • Requires smart actuation (surface-dependent) Surface with firm spines Surface with compliant spines & adhesive pad
Single Mechanism for all surfaces? • Clever sprung claw design, like Moto’s hummingbird foot • Maximize penetration on soft surfaces • Minimize push-off force on smooth surfaces
What needs to be done • Decide on mechanism(s) to include in foot • Consider front/rear foot specialization! • Test current foot designs on test track: • Measure maximum adhesion and shear force from each foot design • Do different feet have different optimum trajectories? • FEA and hand calcs to determine good geometries for polyurethane or dry adhesive pads • FEA and hand calcs to develop flexures