Document Type


Date of Award

Fall 10-31-1997

Degree Name

Master of Science in Mechanical Engineering - (M.S.)


Mechanical Engineering

First Advisor

Zhiming Ji

Second Advisor

R. S. Sodhi

Third Advisor

Taiming Chu


OSCAR, or Operational Space Controlled Adjustable Robot, is a parallel-actuated manipulator, also known as Stewart Platform or platform manipulator. The apparatus consists of two platforms (base and top) and six prismatic actuators in between. The main advantage of a platform manipulator is the fact that it can out-perform serial manipulators in both load capacity and precision. However, there are disadvantages and weaknesses such as limited mobility. A platform manipulator has reduced workspace compared to serial manipulators. The problem of limited workspace is solved by enabling OSCAR to change its prismatic leg positioning about the base platform.

During the course of the research, the writer designed various parts of the platform manipulator to attend to particular needs using different computer-aided design packages. Once the design was completed and rendered feasible, the parts were actually manufactured and assembled. Some parts were designed to incorporate optical encoders. The feed-back information obtained from the encoders can be used to analyze the manipulator's forward kinematics. Since the forward kinematics is solved using matrices, singularities must be avoided at all times. Singularity found in matrix will suggest the jamming of the manipulator.



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