Kinematic analysis and control of limited 4-DOF parallel manipulator based on screw theory

This paper describes the development of a dexterous endoscopic parallel manipulator for laparoscopic surgery using rigid mechanism. Endoscopic parallel manipulator is developed based on the concept of virtual chain and screw theory. The inverse and forward kinematics solutions are derived analytically and numerically respectively. Also the singularity analysis is investigated. The known problem of limited bending angles was solved in the proposed manipulator as it can reach ± 90° in any direction. The proposed manipulator consists of four legs; two legs are 2-PUU (each leg consists of one active prismatic joint and two passive hook joints); the other two legs are 2-PUS (each leg consists of one active prismatic join, one passive hook joint and one passive spherical joint). The virtual prototype of the parallel mechanism was constructed in ADAMS. The kinematics simulation of the virtual prototype was realized. Four linear motors are used to drive the mechanism. The intuitive simulations with the combination of MATLAB/Simulink and ADAMS show that the control performance of kinematics analysis is satisfactory.