Modelling and optimisation of a 4-DOF hybrid robotic manipulator

The global compliance and global condition index of a 4-degrees-of-freedom hybrid robotic manipulator are modelled and optimised. The kinematic analysis of the hybrid robotic manipulator is studied in detail. The manipulator compliance model is obtained and the summation of the main leading diagonal elements of the compliance matrix, which is known as the global compliance, is employed as a criterion to assess the rigidity of the mechanism. The global condition index, which is obtained by the Monte Carlo technique, is employed as a criterion to assess the mechanism workspace. It is found that increasing the mechanism workspace will lead to the mechanism compliance increase. Thus, the global compliance and the global condition index of the manipulator are optimised simultaneously. The optimised results are analysed and compared. The proposed mechanism design can be potentially used as machine tools in manufacturing assembly and processes applications.