Gravity and friction compensation algorithm for master manipulator based on genetic algorithm

In this paper, we built a Lagrange dynamical model for an interactive master manipulator based on Delta parallel mechanism. Genetic Algorithm was used to identify the static parameters in the LuGre friction model with regard to high non-linearity friction torque of the driving parts. The Stribeck curve relating rotational velocity with static friction torque for each driving part was obtained. To acquire the real-time position, velocity, and acceleration of the manipulator during passive operation, Galil motion controller was used to record the driving angle and angular velocity. By using difference method, the angular acceleration can be calculated. With the control torque calculated by the dynamical equation for each motor, the gravity, driving friction of the manipulator at any position can be compensated. Lastly, an algorithm was designed for resistant compensation and experiment was carried out to validate the algorithm. The results showed that the traction users need to apply is reduced magnificently by 93% on average after resistant compensation.