Reliability modeling and simulation evaluation of a helicopter control system based on a digital prototype

Abstract

As a core flight control actuator, the reliability of the helicopter control system directly affects the flight safety of the entire aircraft. Driven by the limitations of traditional physical prototype reliability tests—namely, lengthy cycles, high costs, and the inability to easily reproduce faults—along with the lack of attention to multi-source uncertainty and nonlinear mechanical-hydraulic coupling in current literature, this paper formulates a novel reliability simulation framework for mechanical-hydraulic composite control systems. We innovatively develop a digital prototype model characterized by strong multi-body dynamics and hydraulic coupling. Transcending the constraints of simplified pure mechanical models, the proposed model accurately maps the complex coupling mechanisms of multi-source uncertainties, including kinematic joint clearance, friction, material fatigue, and hydraulic leakage. Based on Monte Carlo simulation and stress–strength interference theory, a quantitative analysis model for system reliability is established, and a dynamic reliability simulation under the full mission-profile load is carried out to obtain the failure probability of key components, the time-varying law of system reliability, and weak links. By comparing with the bench test data, the simulation reliability error is less than 0.83%, verifying the validity of the model. The research shows that this method can efficiently predict and optimize the reliability of the control system throughout its life cycle, providing theoretical support for the digital design and reliability improvement of the helicopter control system.