Abstract
In the flight control system, using an electro-hydrostatic actuator (EHA) instead of the currently used relatively mature electro-hydraulic valve-controlled actuator, there are three prevailing concerns, namely heating, size, and stiffness. This paper proposes a novel principle EHA, called active load-sensitive EHA (ALS-EHA), which can actively realize the adaptive adjustment of pump displacement with load pressure. Its principle analysis and mathematical modeling based on the direct load-sensitive EHA (DLS-EHA) configuration is done to obtain the relationship between motor current and hydraulic reduction ratio. Then, its stiffness characteristics are analyzed, especially the influence of hydraulic reduction ratio on impedance at low frequencies combined with investigating the power matching of ALS-EHA. A comparative experiment between the developed ALS-EHA and the EHA with fixed pump displacement and variable motor speed (EHA-FPVM) was carried out. The results reveal that the proposed ALS-EHA can reduce the motor heating and its displacement tracking error is smaller near zero speed owing to its higher impedance from the lower hydraulic reduction ratio under heavy load conditions.
Highlights
As the “skeleton” and “muscle” of the aircraft structure, the flight control actuation system plays an irreplaceable role in its structure [1,2,3]
Based the simple structure of DLS-electro-hydrostatic actuator (EHA), the active load-sensitive EHA (ALS-EHA) which is mainly studied in this paper is derived and the load sensitive characteristics are studied by means of mathematical modeling
The direct load-sensitive EHA (DLS-EHA) schematic is displayed in Figure 3. the load-sensitive servo mechanism uses a shuttle valve to guide the pressure of the high-pressure chamber of the EHA to the swash plate
Summary
As the “skeleton” and “muscle” of the aircraft structure, the flight control actuation system plays an irreplaceable role in its structure [1,2,3]. Most civil and military aircraft use a central hydraulic oil source for centralized fluid supply, adopt engine-driven pumps to provide high pressure, and employ servo valves to implement servo control of the rudder surface and landing gear through the throttle principle [2,3,4]. This method has mature technology and good dynamic performance, but low efficiency and complex pipeline layout problems have become the main factors restricting the further improvement of aircraft performance [5].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
