Dynamic Speed Tolerance for Aircraft Vertical Navigation
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Solution Overview
Problem
Current vertical navigation control algorithms for aircraft descent result in inaccurate Estimated Time-of-Arrivals (ETAs) due to varying airspeed caused by uncertainties in wind and temperature estimates, leading to difficulties in adhering to Required Time-of-Arrival (RTA) constraints.
Innovation Solution
A control system that dynamically adjusts the speed control tolerance range based on the RTA error and tolerance, using a processor to generate thrust or drag control signals to maintain accurate time control while adhering to a defined vertical profile, allowing for more precise time management during aircraft descent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed speed control tolerance range is used in traditional vertical navigation control, then the aircraft can maintain a simple control strategy, but the Estimated Time-of-Arrival becomes inaccurate due to speed fluctuations
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed speed control tolerance range to a dynamically adjustable tolerance range. The control system continuously monitors the difference between actual and predicted ground speed, and adjusts the speed control tolerance range in real-time based on this discrepancy and wind/temperature uncertainty levels. This dynamic adjustment enables accurate Time-of-Arrival prediction while adapting to changing flight conditions.
Solution Approach 2:
The patent implements parameter changes by modifying the speed control tolerance range parameter based on flight conditions. Specifically, the tolerance range is adjusted as a function of ground speed difference and environmental uncertainty, allowing the control system to optimize Time-of-Arrival accuracy without requiring complete redesign of the control architecture.
2Ease of operation
If a large speed control tolerance range is used, then the control system is easier to operate, but large thrust corrections are required which impact passenger comfort
Solution Approach 1:
The patent uses dynamics to adjust the speed control tolerance range in real-time based on the aircraft's proximity to the desired Time-of-Arrival and current flight conditions. When the aircraft is on track to meet the RTA, a larger tolerance range is permitted, simplifying control. When corrections are needed, the tolerance range is reduced, enabling smaller, smoother thrust adjustments that maintain passenger comfort.
Solution Approach 2:
The patent implements feedback by continuously monitoring the difference between actual and predicted ground speed, and using this information to adjust the speed control tolerance range. This closed-loop approach ensures that the control system responds appropriately to deviations from the desired trajectory, minimizing unnecessary thrust corrections while maintaining ease of operation.
3Measurement precision
If a small speed control tolerance range is used, then the Time-of-Arrival control is more accurate, but the pitch control varies continuously affecting passenger comfort
Solution Approach 1:
The patent applies dynamics by making the speed control tolerance range adjustable rather than fixed. The tolerance range is dynamically modified based on the difference between actual and predicted ground speed, allowing the system to maintain tight control when needed while permitting smoother operation when the aircraft is on track. This prevents continuous pitch variations that would discomfort passengers.
Solution Approach 2:
The patent implements parameter changes by modifying the speed control tolerance range parameter as a function of flight conditions and Time-of-Arrival accuracy requirements. This allows the system to optimize the balance between control precision and passenger comfort by adjusting the tolerance parameter rather than maintaining a constantly small range that would cause excessive pitch activity.
4Device complexity
If the throttle is fixed at idle setting with elevator control, then the control strategy is simplified, but the speed varies significantly from target speed when wind and temperature estimates are inaccurate
Solution Approach 1:
The patent applies dynamics by transitioning from a static idle-throttle control strategy to a dynamic control approach where the throttle setting is continuously adjusted based on the difference between actual and predicted ground speed. The system dynamically modifies both the throttle command and the speed control tolerance range to maintain accurate speed control while accounting for wind and temperature uncertainties.
Solution Approach 2:
The patent implements parameter changes by modifying the throttle setting parameter away from a fixed idle position. Instead, the throttle parameter is continuously adjusted as a function of ground speed discrepancy and environmental conditions, enabling the system to maintain accurate speed control while keeping the control strategy relatively simple through automated parameter adjustment.
Data Source
AI summary
A method and systems for controlling a speed of a vehicle are provided. The control system includes an input device configured to receive a required time of arrival (RTA) at a waypoint and a processor communicatively coupled to said input device, said processor programmed to automatically determine a dynamically adjustable range for an autothrottle control using an RTA error and a speed control tolerance, the RTA error representing a difference between an estimated time of arrival (ETA) and the RTA, the speed control tolerance representing a tolerance range about the vehicle speed profile. The control system also includes an output device communicatively coupled to said processor, said output device is configured to transmit at least one of a thrust control signal and a drag control signal to a speed control system of the vehicle.