Date of Award

4-2020

Access Type

Thesis - Open Access

Degree Name

Master of Science in Aerospace Engineering

Department

Aerospace Engineering

Committee Chair

Dr. Richard Prazenica

First Committee Member

Dr. Troy Henderson

Second Committee Member

Dr. Morad Nazari

Abstract

Robotic arms are traditionally mounted to rigid structures as they perform tasks. As a result, the arm’s movement would not affect the position of its mount and its operational space that it is performing a task within would remain constant. If a robotic arm were to function in orbit, the motion of the arm would cause it to rotate and translate about its center of mass, which changes as the joints of the arm rotate.

The purpose of this thesis is to focus on the two-dimensional translational effects of an arm operating on a simulated zero-friction surface and provide a method to anticipate and stabilize these induced forces. By calculating the forces generated by the movement of a 7-DOF Sawyer robotic arm using the arm’s Universal Robotics Description Format (URDF) parameters provided by Spear (2017) and a Denavit-Hartenberg method for the geometric solution of the arm’s kinematics, the induced motion caused by the arm’s movement can be arrested by an efficient control system. Using an XY-table to compensate for the induced motion of the arm, a comparison is made for an open-loop and closed-loop control of a cable driven XY-table. From this analysis, a better understanding of an active mount solution for robotic arms can be identified. The key findings of this research are the validation of open-loop control response based on the calculated reaction force provided by kinematic analysis of the robotic arm’s center of mass. Additionally, a closed-loop control response is assessed based on an applied external force to the system during operation. Both results lead to a controlled system displacement error that does not exceed 1e10-14 meters for the four test cases presented.

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