Aircraft Nose Wheel Heading Control Under Asymmetrical Thrust
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Solution Overview
Problem
Modern aircraft with shorter wheelbases are sensitive to steering inputs, limiting the range of nose wheel angle control during ground manoeuvres, and asymmetrical thrust conditions exacerbate yawing moments, particularly in dual-engine aircraft with engines under each wing, leading to unintended heading changes and increased workload for flight crews.
Innovation Solution
A heading control system that adjusts nose wheel angle using a bias signal to determine an offset angle, allowing controlled steering within a defined angular range, optionally centered on the aircraft's longitudinal axis, and includes automated steering with adjustable gain terms to compensate for asymmetrical thrust and external factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the range of nose wheel angle control is increased to compensate for asymmetrical thrust and external factors, then the ability to maintain stable heading is improved, but the risk of severe lateral movement increases in aircraft with shorter wheelbases
Solution Approach 1:
The patent implements dynamic adjustment of the angular range based on aircraft characteristics and operating conditions. The control system automatically adapts the maximum nose wheel angle deflection limits according to the aircraft's wheelbase length, ground speed, and phase of operation (takeoff, landing, taxiing). This allows the system to provide adequate compensation for asymmetrical thrust during normal operations while preventing excessive steering inputs that could cause lateral movement in shorter wheelbase aircraft.
Solution Approach 2:
The system changes the control parameters (angular range limits) based on detected aircraft state and environmental conditions. By monitoring variables such as ground speed, aircraft type, and phase of flight, the control system adjusts the permissible nose wheel angle range in real-time, optimizing both heading stability and safety for different operational scenarios.
2Ease of operation
If automated heading control is implemented to reduce flight crew workload, then the ease of operation is improved, but the complexity of the control system increases
Solution Approach 1:
The heading control system operates autonomously by continuously monitoring aircraft state parameters (ground speed, heading, engine thrust asymmetry) and automatically adjusting the nose wheel angle to maintain desired heading. The system self-regulates without requiring manual intervention from the flight crew, reducing workload while managing complexity through integrated sensor processing and automated control algorithms.
Solution Approach 2:
The system incorporates feedback loops that continuously monitor aircraft heading, ground speed, and engine performance, comparing actual values with target values and automatically adjusting nose wheel position to correct deviations. This closed-loop control approach maintains simplicity by using readily available sensor data and straightforward control logic to achieve automated heading maintenance.
3Object-affected harmful factors
If engine thrust is reduced to minimize noise and pollution during ground manoeuvres, then environmental impact is reduced, but asymmetrical thrust conditions exacerbate yawing moments
Solution Approach 1:
The system converts the harmful effect of asymmetrical thrust-induced yawing moments into a controllable parameter by using the heading control system to automatically compensate for the yawing tendency. Rather than preventing asymmetrical thrust operations, the system accepts them as normal operating conditions and provides automated correction, enabling environmentally friendly single-engine taxiing while maintaining heading stability.
Data Source
AI summary
A heading control system for an aircraft arranged to maintain a heading of an aircraft by controlling a nose wheel angle of the aircraft. The heading control system includes an interface arranged to receive a bias signal indicating a bias towards the port or the starboard of the aircraft and one or more processors. The one or more processors are arranged to determine, based on the bias signal, an offset angle defining an offset from a longitudinal axis of the aircraft and to perform a control process to control the nose wheel angle within an angular range based on the offset angle.