Abstract: Pneumatically robotic manipulator with 3 degrees of freedom belongs to serial mechanisms. During the movement of robotic manipulator, parameters such as rotation inertia, gravity torque and coupling torque between joints change greatly, which affects the motion precision of robotic manipulator. In order to solve the problems, dynamic analysis of manipulator’s three joints are carried out by using Lagrange equation. The waist joint is taken as an example to illustrate design of controller for joint. Through linearizing the mathematical model of power mechanism, the method of state feedback pole-assignment is applicable to the design of controller. The result shows that the single joint controller is robust, but there is certain static error. The error is mainly caused by the influence of disturbance torque. Dynamic compensation as the feed forward compensation for single joint controller is obtained by calculating single joint trajectory planning based on dynamic model. The experiment shows that the method is effective and improves the precision of the trajectory tracking.

Key words: Dynamics model, Feed forward compensation, Linearization, Pole assignment, Trajectory tracking