Adaptive Variable Admittance Force Tracking Control with Variable Update Rates

Collaborative robots rely highly on the accuracy of force tracking for precise interaction with the external environment. Low accuracy in force tracking may cause damage to the environment or the manipulator. To address the problem of existing variable impedance force tracking methods being inadequate for complex dynamic environments, an adaptive variable admittance force tracking control method based on variable update rates is designed, which can change the update rate of the damping coefficient according to the velocity and acceleration changes at the end of the robotic arm, thereby enabling the robotic arm to have better force tracking performance. By zero-point and gravity compensation algorithms and adaptive updating rates of damping parameters, this method not only reduces the impact force when the manipulator meets the environment but also significantly improves the accuracy of force control. Through the utilization of the adaptive updating rates of damping parameters, the control precision of force tracking is enhanced, leading to a reduction in force tracking errors. Finally, the control algorithm was validated through simulations and experiments.