Main Rotor Tilt Control for Stable Low-Speed VTOL Flight
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Solution Overview
Problem
Existing aircraft systems face challenges in accurately controlling the tilt angle of main rotors during low-speed flight, especially in windy conditions, as inertial speedometers do not account for wind speed, leading to inaccurate airspeed measurements and unstable flight characteristics.
Innovation Solution
A vertical take-off/landing aircraft system that controls the tilt angle of the main rotor based on a vertical posture control signal, using a flight controller to generate tilt angle control signals in conjunction with pitch posture angle control signals, adjusting the rotation axis of the main rotor to compensate for wind effects and maintain stable flight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If GPS-based inertial speedometer is used to measure speed at low speeds, then speed measurement capability is improved, but measurement precision deteriorates due to wind not being reflected in inertial speed
Solution Approach 1:
The patent introduces a mediator system that combines GPS inertial speed data with wind speed information from a separate sensor. This intermediary system processes both data sources to generate corrected airspeed measurements, resolving the contradiction between low-speed measurement capability and measurement precision in windy conditions
Solution Approach 2:
The system implements feedback by continuously comparing inertial speed measurements with actual airspeed data from wind sensors, then adjusting the tilt angle control based on the difference. This feedback loop compensates for wind effects and maintains measurement precision across varying flight conditions
2Device complexity
If main rotor tilt angle is controlled based on inertial speed, then flight control is simplified, but reliability deteriorates in windy environments where air speed changes
Solution Approach 1:
The patent merges the inertial speed measurement system with a wind speed sensing system into an integrated control architecture. By combining these previously separate systems, the patent maintains control system simplicity while improving reliability through compensated airspeed data that accounts for wind conditions
Solution Approach 2:
The system dynamically changes the control parameter from raw inertial speed to corrected airspeed that incorporates wind compensation. This parameter transformation allows the simplified control system to reliably respond to actual aerodynamic conditions rather than uncorrected inertial data
3Measurement precision
If air speed speedometer is used to measure dynamic pressure, then flight characteristic measurement is improved, but ease of operation deteriorates due to minimum speed limitations
Solution Approach 1:
The patent creates a universal measurement system that can accurately measure both high-speed and low-speed flight characteristics by integrating multiple sensing approaches. The system automatically selects and combines appropriate measurement methods based on flight regime, extending operational range while maintaining measurement precision across all speeds
Data Source
AI summary
Provided is a vertical take-off/landing aircraft controlling a tilt angle of a main rotor, based on a vertical posture control signal during low-speed flight, wherein, when an aircraft steering signal including a vertical posture control signal for changing the pitch posture angle of the vertical take-off/landing aircraft by a first pitch posture angle is obtained, a flight controller determines a tilt angle of the main rotor with reference to the first pitch posture angle and generates a tilt angle control signal for the main rotor based on the determined tilt angle.