Real-time PID self-healing control method for aero-engine rotor vibration based on piezoelectric-driven bearing clearance adjustment

Abstract

This paper proposes a real-time control method for rotor vibration in aero engines utilizing PID control. This approach addresses sudden rotor imbalances caused by external impacts, material failures, combustion instabilities, and other factors that lead to severe vibrations. This study investigates the relationship between bearing clearance and rotor vibration response. A finite element analysis of the rotor system is conducted to elucidate how bearing clearance variations affect the rotor vibration amplitude. A PID control model is established, and PID parameters are determined. When the vibration surpasses the predetermined threshold, the piezoelectric ceramic alters the bearing clearance of the squeeze oil film damper. This adjustment modifies the damping, which helps mitigate the unbalanced vibration response of the rotor. The software for rotor vibration self-healing control based on PID control was designed and developed, and a corresponding rotor vibration control system was built for experimental verification. The results indicate that applying a 7 kg/mm unbalance to the secondary gas turbine disk of the rotor at a speed of 2700 r/min, with k _p set to 0.9, k _i to 0.1, k _d to 0.0002, and a bearing clearance threshold of 40 μm, yields significant findings. Employing PID control results in an optimal vibration control amplitude of 39.88 μm and a vibration reduction rate of 66.4%, representing approximately 22% improvement over traditional control methods. The method proposed in this paper offers novel insights into the control of sudden rotor vibration in aero engines.