Rotorcraft Control System Ground Reaction Force Switching
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Solution Overview
Problem
Conventional rotorcraft control systems are inadequate for safe and efficient operations during take-off and landing phases, particularly on sloping ground, as they can cause tilting, ground resonance, and reduced control authority due to the activation of in-flight control laws on the ground, leading to increased pilot workload and risks like pilot-induced oscillations.
Innovation Solution
A control system that uses sensors to detect ground reaction forces and switch between distinct control laws based on flight or ground states, maintaining active integrators to retain control authority and prevent ground resonance, with adjustable integral correction dynamics to manage stress and ensure stable rotorcraft control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If ground control laws with different structure and gains are used, then ground contact stability is improved, but transition smoothness deteriorates
Solution Approach 1:
The control system uses dynamic switching with smoothing logic to transition between ground and flight control laws. Rather than abrupt switching, the system monitors transition phases and applies smooth interpolation or staged activation of control laws, maintaining ground contact stability while ensuring smooth transitions during phase changes.
2Object-affected harmful factors
If integrators are deactivated on ground contact, then ground resonance is prevented, but control authority is lost
Solution Approach 1:
The system extracts and removes the integrator component specifically during ground contact operations. By taking out the integrator function when on the ground, the system prevents ground resonance while maintaining full control authority through proportional and derivative control components that remain active.
3Ease of operation
If proportional gains and integral time constants are adjusted for ground operations, then ground maneuverability is improved, but flight control performance deteriorates
Solution Approach 1:
The control system dynamically adjusts proportional gains and integral time constants based on the operational phase. During ground operations, optimized ground parameters are applied to improve maneuverability, while in-flight parameters are restored when airborne to maintain flight control performance. This dynamic parameter adaptation resolves the contradiction by ensuring optimal parameters are active for each phase.
Data Source
Figure 1~2
Figure 3~4
AI summary
The present invention relates to a control system (1) for a rotorcraft (4) comprising at least one control element (2) for steering a rotor (3, 13) of a rotorcraft (4), the rotorcraft (4) comprising at least three independent landing gears (5, 6, 7), each landing gear (5, 6, 7) comprising means for detecting (8) a reaction force F1, F2, F3 of the ground acting on the landing gear (5, 6, 7) when the rotorcraft (4) is in contact with the ground, the control system (1) being capable of receiving information from the detection means (8). The invention also relates to the rotorcraft (4) and a control method corresponding to the control system (1).