Design and control of a simplified Stewart platform for endoscopy

Presents the development of a workspace controller for a newly designed platform. The platform is designed to manipulate endoscopic tools and is actuated by tendons to meet the small scale requirements in endoscopy. The tendon actuation provides challenges to the controller design since the number of degrees of freedom equals the number of tendons. In typical tendon-driven systems, the number of tendons is greater than the number of degrees of freedom. This paper presents the kinematic and dynamic analysis of the manipulator and presents a workspace controller for the tendon driven system. Simulation as well as experimental results are presented for the controlled system. The results demonstrate the effectiveness of the controller in tracking a step response and a circular trajectory at 2.0 Hz and greater. The device is similar to the Stewart platform and the basic design can be used in applications where the fall range of motion of the Stewart platform is not required. Applications of the device range between targeting systems, snake-like robots, and endoscopy.<
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