Oscillation Analysis of UAV Hydraulic Servo Actuation System

Unmanned Aerial Vehicles (UAVs), as uncrewed aircraft, can perform various dangerous and challenging tasks. However, the resonance issues in their Hydraulic Servo Actuator (HSA) systems can significantly affect the stability and control precision of the aircraft, necessitating in-depth research on this phenomenon. This paper first establishes a mathematical simulation model for the HSA, which includes models for the direct drive servo valve, hydraulic actuator, and load characteristics. Subsequently, through theoretical and simulation analysis of the hydraulic-mechanical comprehensive resonance in the HSA, it is discovered that insufficient mounting stiffness and control stiffness are the key factors leading to system oscillations. Finally, by incorporating support clearance and control clearance models into the system and conducting simulations, it is found that control clearance is the primary cause of oscillations. However, the presence of support clearance extends the oscillation duration in the time domain. Therefore, in practical applications, both types of clearance should be minimized as much as possible.