Impedance fuzzy control of an active aircraft landing gear system

In this paper, a new approach is proposed to control the dynamic behavior of a landing gear system for providing the passenger comfort and aircraft handling subject to the runway disturbances. The proposed control system includes three interior loops. The inner loop is responsible for controlling actuator force by a PI controller, the middle loop controls the body position by a PD-like fuzzy controller and the outer loop is the impedance control loop. The novelty of control system is the use of impedance rule in determining the reference body position. The impedance rule has been considered as a linear second order system that is able to provide a suitable trade-off between two objectives: passenger comfort and aircraft handling. The impedance control provides a suitable dynamic behavior for the landing gear in wide range of runway conditions including a bumpy or flat ground. Performance of the control system is evaluated and compared with passive system using computer simulation. The results illustrate that impedance control is successful in decreasing the vibrations and improving both passenger comfort and aircraft handling.