DYNAMIC STIFFNESS ANALYSIS OF ELECTRO-HYDRAULIC SERVO-CONTROLLED HYDRAULIC MOTOR

Electro-hydraulic servo control systems find widespread applications in aerospace, engineering machinery, and robotics, where they are integral to maintaining the performance and safety standards of aircraft. This study focuses on examining the dynamic stiffness properties of hydraulic motors in these systems and analyzes how different parameters affect dynamic stiffness. Dynamic stiffness describes an actuator's rigidity and response characteristics in motion control scenarios, reflecting the stability and performance of aircraft actuators under complex dynamic operational conditions more accurately than static stiffness. The study employs modular modeling to establish a mathematical model for dynamic stiffness, revealing that the servo valve inherent frequency, damping coefficient, pipeline volume, and hydraulic oil bulk modulus exhibit low sensitivity. Proportional gain, servo valve gain, and servo valve flow coefficient show consistent sensitivity curves, indicating a strong correlation. Conversely, the leakage coefficient and hydraulic motor displacement sensitivity negatively correlate with frequency, while hydraulic motor inertia, damping coefficient, and gearbox reduction ratio positively correlate with frequency. These insights enhance the understanding of parameter impacts, aiding in the design and optimization of high-power-to-weight ratio hydraulic systems for aerospace applications.