Modeling and control of helicopter flight control system with a controllable Semi-rotary fluid viscous damper

To improve the handling comfort of Helicopter Flight Control System (HFCS), an adaptive particle swarm optimization optimized variable universe fuzzy proportional-integral-derivative (APSO-VUFPID) strategy for damping force control is proposed. First of all, by the results of the controllable semi-rotary fluid viscous damper (CSFVD) mechanical tests, a hyperbolic tangent model is developed. Afterwards, an equivalent model of HFCS is established. In the next part, aiming at improving the vibration suppression performance of the joystick system, an APSO-VUFPID is proposed to generate the desired damping force in real-time. Finally, numerical simulation and experimental tests are carried out to verify the vibration reduction effect of the proposed APSO-VUFPID method with respect to passive, proportional-integral-derivative (PID), adaptive particle swarm optimization optimized proportional-integral-derivative (APSO-PID) and adaptive particle swarm optimization optimized fuzzy proportional-integral-derivative (APSO-FPID) methods. The results show that the hyperbolic tangent model can accurately describe the nonlinear mechanical characteristics of the CSFVD. Moreover, under the proposed APSO-VUFPID control method, the amplitude of acceleration and velocity of the joystick system are smaller than those obtained from passive, PID, APSO-PID and APSO-FPID methods. Therefore, the proposed APSO-VUFPID controller has better handling comfort compared to passive, PID, APSO-PID and APSO-FPID controllers and can be employed in real applications.