Aircraft Speed Estimation via Aerodynamic Hinge Moments
Solution Overview
Problem
Conventional methods for determining an aircraft's speed during flight require total air pressure measurements, making them costly and complex, and lacking these sensors renders speed estimation impossible.
Innovation Solution
A method and device that estimate aircraft speed by determining aerodynamic hinge moments of control surfaces, external static pressure, and hinge moment coefficients to compute Mach number without total air pressure measurements, using expressions like Ma=12γPs²VδpCh, and employing schemes like Least-Squares Sliding-Mode observers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If total air pressure sensors (Pitot probes) are used to determine aircraft speed, then measurement accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The invention extracts the speed estimation function from the traditional total air pressure measurement system. Instead of using Pitot probes to directly measure total pressure and compute speed, the method extracts speed information indirectly through aerodynamic hinge moment measurements from control surfaces, thereby eliminating the need for total air pressure sensors while maintaining speed determination capability
Solution Approach 2:
The control surface actuator system, originally designed solely for controlling flight surfaces, is made multi-functional by also using it as a sensor system for speed estimation. The hinge moment measurements taken for control purposes now serve dual purposes: controlling the flight surface and providing data for Mach number calculation, thus eliminating dedicated speed measurement sensors
2Reliability
If total air pressure sensors are installed on the aircraft, then speed determination capability is improved, but aircraft weight increases
Solution Approach 1:
The invention removes the weight burden of total air pressure sensors (Pitot probes and associated static pressure sensors) from the aircraft. Speed determination capability is extracted and relocated to the flight control computer, which processes hinge moment data from the actuator system to compute Mach number, thereby maintaining reliability while reducing weight
3Measurement precision
If conventional speed measurement systems are used, then accurate speed data is obtained, but processing chain complexity increases
Solution Approach 1:
The invention merges the speed measurement function with the existing flight control data processing chain. Instead of having a separate measurement system that feeds into the control system, the hinge moment data from the actuator system is directly integrated into the flight control computer's processing chain, where speed estimation is performed alongside other flight control functions, thereby simplifying the overall processing architecture
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables real-time, automatic speed estimation of aircraft without total air pressure sensors, reducing weight, cost, and complexity, while accurately accounting for aerodynamic forces and other flight parameters.
Implementation Method 1
This aerodynamic hinge moment illustrates the aerodynamic forces acting on the control surface of the aircraft in the course of the flight. These forces depend on the speed of the aircraft, and also on a plurality of other parameters
Data Source
AI summary
A device including a first data generating unit for determining at least one aerodynamic hinge moment of at least one control surface of the aircraft, a second data generating unit for determining a plurality of data and at least one external static pressure and a model of hinge moment coefficient, a computation unit for computing with the aid of these data at least one speed of the aircraft, namely a Mach number and/or a conventional speed, and a data transmission unit for providing this speed to a user system.