This paper deals with the design process and the dynamic control simulation of a new type of 4-DOFs parallel mechanism that can be used as an endoscopic surgical manipulator. The proposed mechanism, 2-PUU_2-PUS, is designed based on the parallel virtual chain concept and screw theory. Based on the structure analysis of the 4-DOF parallel mechanism, the inverse position equation is studied using the inverse analysis theory of kinematics. The design and the stress analysis of the mechanism are investigated using SolidWorks software. The virtual prototype of the parallel mechanism is constructed, and the dynamic simulation is performed using ADAMS™ software. The system model utilizing PID and PI controllers has been built using MATLAB software. A more realistic simulation in accordance with a given bending angle and point to point control is implemented by the use of both ADAMS/MATLAB softwares. The simulation results showed that this control method has solved the coordinate control for the 4-DOF parallel manipulator so that each output is feedback to the four driving rods. From the results, the tracking performance is achieved. Other control techniques, such as intelligent ones, are recommended to improve the tracking performance and reduce the numerical truncation error.

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.