Date of Award

8-2019

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Electrical and Computer Engineering (Holcomb Dept. of)

Committee Member

Richard E Groff, Committee Chair

Committee Member

Joseph Singapogu

Committee Member

Ian D Walker

Abstract

This paper details the design of a six degree-of-freedom low-cost force/torque sensing platform for use in a suturing simulator for surgical training. This platform is based on the Stewart Platform configuration in which the linear actuators are replaced with metal wire kept in tension by multiple elastically loaded support columns. Flexible wire legs are used in lieu of rigid connectors so as to reduce the platforms susceptibility to inter-component friction in measurements and to allow the platform to exhibit built-in stress relief for the cantilevers in directions of concern. The static structural elements of the platform are designed to be manufactured from standard 3D printing technology, decreasing the overall weight of the platform while keeping costs low and allowing for quick replacement of any damaged structural elements. Due to errors in fabricating the cantilevers, a slow transient response is observed in the platform's voltage outputs which is carried over into the measured loads on the platform. By experimenting with different cantilever designs and the techniques used to manufacture them, new cantilever designs are proposed which correct for the slow transient response. The platform is calibrated by applying standardized weights to cause forces and torques in each axes and sampling the corresponding voltage outputs. When the platform is subjected to unknown loads after calibration, the platform measures forces and torques in each axes for short periods of time with errors attributable to the non-linear response. Tests simulating the suturing system are conducted on the platform with the results showing that the platform is able to measure forces and torques in each axes at any position on the membrane. While the current sensor cannot be used in the suturing system as is, implementing the new cantilever design in the platform will make the platform an inexpensive component capable of providing accurate measurements of the loads on the membrane.

Share

COinS