System And Method For Controlling Rotorcraft
Patent No. US11247782 (titled "System And Method For Controlling Rotorcraft") was filed by Textron Innovations Inc on Sep 21, 2018.
What is this patent about?
’782 is related to the field of rotorcraft flight control systems, specifically addressing engine management during engine failure scenarios. Modern rotorcraft often employ multiple engines for redundancy, ensuring continued operation even if one engine fails. The challenge lies in rapidly and safely increasing the output of the remaining engine(s) to compensate for the lost power, while avoiding potentially damaging over-torque or over-temperature conditions.
The underlying idea behind ’782 is to dynamically adjust the rate at which the remaining engine's power is increased following an engine failure. This is achieved by monitoring an operating parameter (like torque, speed, or temperature) of the functioning engine and comparing it to a nominal limit . The difference between the operating parameter and the limit determines the 'headroom' available, which is then used to calculate an appropriate 'ramping rate' for increasing the engine's output.
The claims of ’782 focus on a method, a rotorcraft, and a flight control computer that, upon detecting an engine outage, receive an operating parameter from a remaining engine, determine an engine output ramping rate based on the difference between that parameter and a nominal limit, and then increase the output of the remaining engine according to that ramping rate. Crucially, the ramping rate has at least two rates of increase, a first rate when the difference between the operating parameter and the nominal limit is less than a predetermined value, and a second, greater rate when the difference is greater than the predetermined value.
In practice, the flight control computer continuously monitors the operating parameters of the engines. When an engine fails, the computer immediately assesses the headroom available in the remaining engine. If the remaining engine is already operating near its limit, the output is increased gradually to avoid exceeding operational limits. However, if the remaining engine has significant headroom, the output is increased more rapidly to quickly restore the rotorcraft's performance.
This approach differs from prior solutions that might use a fixed ramping rate or a simple step increase in power. By dynamically adjusting the ramping rate based on real-time engine conditions, ’782 allows for a more responsive and safer transition to single-engine operation. This prevents potentially damaging overshoots while maximizing the available power from the remaining engine, improving the rotorcraft's ability to maintain altitude and maneuverability after an engine failure. The use of a lookup table or runtime calculation allows for flexible implementation of the ramping rate determination.
How does this patent fit in bigger picture?
Technical landscape at the time
In the late 2010s when ’782 was filed, rotorcraft flight control systems were at a time when fly-by-wire systems were being implemented to assist pilots in stably flying the rotorcraft and to reduce workload on the pilots. These systems commonly relied on flight control computers disposed between the pilot controls and flight control systems, providing corrections to flight controls that assist in operating the rotorcraft more efficiently or that put the rotorcraft into a stable flight mode while still allowing the pilot to override the FBW control inputs. At this time, it was typical to use multiple engines in rotorcraft, and hardware or software constraints made it non-trivial to quickly and safely adjust engine output in response to an engine failure.
Novelty and Inventive Step
The examiner allowed the claims because Lescher discloses detecting and reacting to a second helicopter engine failure, including a rotorcraft with multiple engines and a flight control computer. Hedrick discloses a precision auto throttle for engine performance adjustment, including retarding the throttle rate if output exceeds a limit. Royer discloses an instantaneous throttle control system that increases flow rate when a lower value is inputted. The examiner stated that it would have been obvious to combine the multiple output throttle rates based on an output limit of Hedrick with the one engine inoperative system of Lescher to return control to the aircraft in an emergency without overloading the system.
Claims
This patent includes 21 claims, with independent claims 1, 11, and 21. The independent claims are directed to a method, a rotorcraft, and a flight control computer, respectively, all relating to managing engine output after detecting an engine outage. The dependent claims generally elaborate on the specifics of the method and the components of the rotorcraft and flight control computer, further defining how the engine output is increased and how the engine output ramping rate is determined.
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Date
Description
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US11247782
- Application Number
- US16138053
- Filing Date
- Sep 21, 2018
- Status
- Granted
- Expiry Date
- May 30, 2039
- External Links
- Slate, USPTO, Google Patents