A Hybrid Nonlinear Active Control Strategy Combining Dry Friction Control and Nonlinear Velocity Compensation Control

Abstract

Friction dampers are widely used in structural vibration suppression in various fields, such as aeronautics, astronautics, robotics, precision manufacturing, etc. Traditional friction dampers are mainly used in a passive way to optimize vibration suppression with an immutable pressure around certain excitation. In this manuscript, a hybrid control strategy by considering both the friction force in the active control law and a nonlinear velocity compensation force is put forward: First, the normal force applied on the friction damper was adjusted to ensure its vibration reduction effect under different excitation for a first passive control; second, the active control law was established by combining the dry friction force and the velocity control force in the state space; lastly, the stability of the nonlinear control law was determined by Lyapunov criterion. Numerical simulations were conducted on a three degree-of-freedom system (3-DOF) based on the proposed hybrid control strategy, to show the control efficiency in vibration suppression and economic efficiency in energy input into the system. Simulation results showed that the proposed control law could reduce the amplitude of the active control force by about 5% without degrading the control efficiency.