Design and fabrication of force sensing robotic foot utilizing the volumetric displacement of a hyperelastic polymer
Name
813136389-MIT.pdf
Description
Full printable version
Size
2.9 MB
Format
Adobe PDF
Checksum (MD5)
b69153a509b937e1381863dbd1bcb1dc
Author(s)
Estrada, Matthew A
Advisor(s)
Sangbae Kim.
Date Issued
2012
Publisher
Massachusetts Institute of Technology
Abstract
This thesis illustrates the fabrication and characterization of a footpad based on an original principle of volumetric displacement sensing. It is intended for use in detecting ground reaction forces in a running quadrupedal robot. The footpad is manufactured as a monolithic, composite structure composed of multi-graded polymers reinforced by glass fiber to increase durability and traction. The volumetric displacement sensing principle utilizes a hyperelastic gel-like pad with embedded magnets and Hall-effect sensors. Normal and shear forces can be detected as contact forces cause the gel-like pad to deform into rigid wells without the need to expose the sensor. A one-time training process using an artificial neural network was used to relate the normal and shear forces with the volumetric displacement sensor output. Two iterations on geometry are prototyped and tested. The first shows the ability to accurately predict normal forces in the Z-axis up to 80 N with a root mean squared error of 6% but little information about shear forces in the X an Y-axis. The second iteration demonstrates an ability to pick up the presence and direction of shear forces up to 40 N but with a root mean squared error of 70%. This project demonstrates a proof-of-concept for a more robust force sensor suitable for use in robotics that requires compliance while interacting with its environment.
Description
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 39-40).
Subjects
Mechanical Engineering.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
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