1 / 10

Pressure Sensor Findings and Thoughts on Future Work

Pressure Sensor Findings and Thoughts on Future Work. Miguel Piedrahita BDML 5/13/04. Pressure Sensor Motivation. Normal force information will be useful for climbing May be able to get dynamic signals related to slipping Pressure approach could integrate nicely with dry adhesive pads.

jatin
Download Presentation

Pressure Sensor Findings and Thoughts on Future Work

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Pressure Sensor Findings and Thoughts on Future Work Miguel Piedrahita BDML 5/13/04

  2. Pressure Sensor Motivation • Normal force information will be useful for climbing • May be able to get dynamic signals related to slipping • Pressure approach could integrate nicely with dry adhesive pads

  3. Chamber Fabrication Mold #1: Mold for Cavity Insert Cavity Insert placed in Mold #2, leaving gap for membrane Completed Cavity Insert (wax or hard urethane) Mold #2: Mold for Membrane Exterior Membrane sealed with layer of hard urethane Membrane cast from soft urethane Mold #3: Mold for sealing off membrane Finished Chamber

  4. Testing Mass • Applied normal force from 0g to 1000g back down to 0g, in 50g increments. • Several trials conducted on two different days.

  5. Results Day 2 Day 1

  6. Sensor Performance (Day 2) Sensitivity: 1.06 kPa/N, (1.06 V/N) Accuracy: +- 0.33 N, or +- 0.35 kPa

  7. Observations • Drawbacks to practical implementation • Difficult to fully bleed air from system – affects repeatability • Size of system limited by rather large sensor • Likely not effective for adhesion forces (front feet) • Other technologies may be better for normal force measurement • Strain gage • Piezoelectric

  8. Thoughts on Future Work:What do we want from RiSE sensors? • Climbing-related information: • Foot impact events • Slip events • Tangential & normal forces on each foot • Measure of penetration of claws/engagement of dry adhesives (i.e. a way to predict likelihood of slip) • Surface-related information: Information about climbing surface would be useful! We could then tailor aggressiveness and climbing strategy (claws vs. dry adhesives) accordingly • Inclination • Surface hardness • Roughness

  9. Array of Instrumented “Lamellar Fingers” Embedded PVDF or strain gage • Force distribution throughout foot – in tension & compression. Useful for evaluating foot design & performance. • Surface roughness by comparing deflections

  10. Why Lamellar Fingers? Good Question! • Examine advantage of lamellar structures • Work on optimizing geometry for front feet and rear feet • Front feet: Maximize surface contact, minimize stress at edges & Poisson shrinkage • Rear feet: Maximize shear force • Solid mechanics, FEA, experiments (RoboToe)

More Related