Composite force sensing foot utilizing volumetric displacement of a hyperelastic polymer

• Main Author: Chuah, Meng Yee (Meng Yee Michael)
• Other Authors: Sangbae Kim.
• Format: Others
• Language: English
• Published: Massachusetts Institute of Technology 2013
• Subjects: Mechanical Engineering.
• Online Access: http://hdl.handle.net/1721.1/78211

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012. === This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. === Cataloged from student-submitted PDF version of thesis. === Includes bibliographical references (p. 65-67). === In this thesis, I will describe the fabrication and characterization of a footpad based on an original principle of volumetric displacement sensing. It is intended for use in detecting ground contact forces in a running quadrupedal robot. The footpad is man- ufactured as a monolithic, composite structure composed of multi-graded polymers which are reinforced by glass fiber to increase durability and traction. The volumetric displacement sensing principle utilizes a hyperelastic gel-like pad with embedded magnets that are tracked with Hall-effect sensors. Normal and shear forces can be detected as contact with the ground which causes the gel-like pad to deform into rigid wells. This is all done 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. The sensor was shown to pre- dict normal forces in the Z-axis up to 80N with a root mean squared error of 6.04% as well as the onset of shear in the X and Y-axis. This demonstrates a proof-of-concept for a more robust footpad sensor suitable for use in all outdoor conditions. === by Meng Yee (Michael) Chuah. === S.M.