Abstract. For a 4-DOF manipulator, The Kinematic Model of Manipulator is built by the method of D-H, Analysis the solution of forward and inverse kinematics of manipulator, The method that algebraic method combined with the geometric method is used to solve forward and inverse kinematics. MATLAB software is used to simulate and get the working space diagram of the manipulator. The Forward and Inverse kinematics and the trajectory planning are simulated by using Robotics Toolbox and this algorithm is proved to be feasible and accurate, which provides the theoretical basis for the subsequent analysis and research of manipulator.

In order to enhance position accuracy of robots, the precise error model is established by applying homogeneous matrix without any differential or partial derivatives required in other methods. An articulated picking manipulator with four-degree-of-freedom is taken as example to analyze the position accuracy affected by errors of geometric parameters (link length, link offset and twist angle). Furthermore, an error compensation algorithm based on error model and inverse kinematics is proposed and applied to the picking manipulator. Experimental simulation was carried out for verifying the feasibility of the presented algorithm, and results show that the maximum position errors in x, y, z axis have declined from 3.2369mm, 9.5583mm, 1.002mm to 0.1334mm, -0.0488mm, -0.001mm after compensation, which could greatly improve the position accuracy of the picking manipulator.