Design of miniature parallel manipulators for integration in a self-propelling endoscope By Kiran .B For: Dr.Challoo Outline Introduction Miniature hydraulic manipulator Valve integration Electrical manipulator Comparison of both manipulators Results Conclusion Introduction • The paper presents two design for a miniature robotic manipulator • Both manipulator designs are based on Stewart platform • These are either driven by hydraulic piston or electromagnetic motors • The system is designed to be used at a pressure of 10 bar Self propelling robotic endoscope Miniature hydraulic manipulator • This design uses the rigid part and is based on classic piston • The advantage is its high stiffness, kinematics and the possibility to have a tool channel running through the centre • The design consists of a three hydraulic pistons connected through ball joints with an outer diameter of 12mm and length of 30mm Manipulator design Exploded view of manipulator Valve integration • To keep the tail of endoscope flexible, valves are introduced instead of tubes • Piezoelectric valve are used where steel ball is used Electromagnetic valve • The construction of valve is based on electronic reluctance force • The reluctance force tends to close the air gap and attracts the pin towards the upper plate, thus closing the valve • The maximum force is obtained when the valve is closed • valve has a length of 12 mm without the needle support, and fits into a cylindrical hole of 3.5 mm diameter Electromagnetic valve design Flow characteristic of the electromagnetic valve Electrical manipulator • Due to the need of hydraulic tubes electrical Stewart platform is developed • The platform has three telescopic legs, each driven by a combination of an electromagnetic micro motor and a micro spindle • The spindle has a pitch of 0.25 mm, what brings the maximum translational speed to 5 mmrs The electric leg prototype in shortest and longest states comparison of both manipulators Conclusion • Two miniature Stewart platforms are under development for integration as a manipulator in a self-propelling endoscope. • The first one is a hydraulic system based on three parallel pistons. • The second manipulator is based on telescopic legs driven by a motor-spindle combination. Reference • P. Dario, M.C. Carrozza, L. Lencioni, B. Magnani, S. D’Attanasio, A • micro-robotic system for colonoscopy, IEEE Int. Conf. Robotics and • Automation, AlbuquerqueNM., 1997, pp. 1567–1572. • w2x J. Peirs, D. Reynaerts, H. VanBrussel, Design of a shape memory • actuated endoscopic tip, Sens. Actuators, A 701998.135–140. • w3x J. Peirs, D. Reynaerts, H. Van Brussel, A micro-robotic arm for a • self-propelling colonoscope, Proc. of 6th Int. Conf. on New Actuators, • Bremen, Germany, 1998, pp. 576–579. • w4x K. Ikuta, M. Tsukamoto, S. Hirose, Shape memory alloy servo • actuator system with electric resistance feedback and application for • active endoscope, IEEE Int. Conf. Robotics and Automation, • PhiladelphiaPN., 1988, pp. 427–430. Any ???
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