Graduation Semester and Year

2010

Language

English

Document Type

Thesis

Degree Name

Master of Science in Aerospace Engineering

Department

Mechanical and Aerospace Engineering

First Advisor

Panayiotis S Shiakolas

Abstract

Parallel robots have been proposed for some time now due to their potential advantages over serial robots in high load bearing, acceleration, stiffness and with lower moving mass. Mobile parallel configurations, i.e. multi-legged walking vehicles have been and are the focus of a great deal of current research. This thesis attempts to provide insights into the kinematic analysis of a quadruped robot capable of both walking and more importantly functioning as a machining tool. The gait analysis of quadruped robots has been extensively investigated and is not the focus of this research; however the gait ability is considered in the presented analysis. Initially, the kinematic analysis of a three degree-of-freedom constrained parallel robot undergoing planar motion is addressed. The solution to the inverse kinematic problem is developed and verified through simulation. The kinematic analysis of a planar robot furnishes the basic understanding of constrained cooperative manipulators and provides the foundation to extend the analysis to 3D space. The kinematics of a quadruped robot consisting of a fixed base and moving platform manipulated by four serial chain legs, with six degrees-of-freedom per leg, undergoing motion in 3D space is then developed. Although a completely general robot with six degree-of-freedom does not have a closed form solution, Pieper's method is applied to solve the inverse kinematic problem. Three different configurations of the legs are analyzed and active and passive degrees of freedom are identified and verified through simulation. Finally, the solution to inverse kinematics to maintain desired position and orientation of the moving platform even when the quadruped legs are positioned on uneven terrain is presented and verified. The results of this thesis provide the foundations for investigating walking machining centers.

Disciplines

Aerospace Engineering | Engineering | Mechanical Engineering

Comments

Degree granted by The University of Texas at Arlington

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