Aircraft Airspeed Determination Using Rotor Models Instead of Pitot Tubes
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Solution Overview
Problem
Existing airspeed measurement methods in aircraft are prone to inaccuracies due to environmental conditions such as ice formation on pitot tubes, leading to improper control inputs and potential adverse events.
Innovation Solution
A method and system utilizing rotor models and operating parameters to determine airspeed by calculating the axial inflow velocity and freestream velocity, eliminating the need for conventional airspeed measurement systems like pitot tubes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional airspeed measurement systems (pitot tubes) are used, then airspeed can be measured, but measurement accuracy deteriorates due to ice formation and environmental conditions
Solution Approach 1:
The patent extracts the airspeed measurement function from the conventional pitot tube system and relocates it to the rotor system. By using the rotor's operating parameters (RPM, blade pitch angle, torque) and aerodynamic models, the measurement function is separated from the vulnerable pitot tube infrastructure, eliminating the harmful effect of ice formation on measurement accuracy.
Solution Approach 2:
The rotor system is given a dual function: it continues its primary propulsion function while simultaneously serving as an airspeed measurement device. By monitoring the rotor's operating parameters and using aerodynamic relationships, the same rotor assembly provides both thrust and accurate airspeed data, eliminating the need for separate measurement systems.
2Measurement precision
If conventional airspeed measurement systems are used, then airspeed indication is provided, but system complexity and aircraft weight increase
Solution Approach 1:
The rotor system performs dual functions as both the propulsion device and the airspeed measurement sensor. By leveraging the rotor's existing operating parameters (RPM, blade pitch angle, torque) and applying aerodynamic models, the system eliminates the need for separate pitot tubes, static ports, and associated heating/anti-ice systems, thereby reducing overall system complexity while maintaining measurement capability.
Solution Approach 2:
The rotor system serves itself by using its own operating parameters to determine airspeed. The same sensors that monitor rotor performance for propulsion control are repurposed to provide airspeed measurement, eliminating the need for dedicated measurement infrastructure and reducing system complexity.
3Measurement precision
If conventional airspeed measurement systems are used, then airspeed data is obtained, but aircraft drag increases
Solution Approach 1:
The patent extracts the airspeed measurement function from the conventional pitot tube system and relocates it to the rotor system. This eliminates the need for additional external sensors and associated mounting hardware, thereby reducing aircraft weight while maintaining measurement accuracy through rotor parameter monitoring and aerodynamic modeling.
4Measurement precision
If conventional airspeed measurement systems are used, then airspeed indication is provided, but reliability deteriorates leading to improper control inputs
Solution Approach 1:
The patent extracts the airspeed measurement function from the vulnerable pitot tube system and relocates it to the rotor system. By using the rotor's operating parameters and aerodynamic models, the measurement is taken out from the environment-exposed pitot tubes that are susceptible to ice formation and blockage, thereby improving reliability and preventing improper control inputs.
Solution Approach 2:
The system uses feedback from the rotor's operating parameters (RPM, blade pitch angle, torque) to continuously monitor and determine airspeed. This closed-loop approach using multiple correlated parameters provides redundant verification and improves the reliability of airspeed indication compared to single-point pitot tube measurements.
Data Source
AI summary
A method for determining airspeed of an aircraft that includes determining a rotor model relating a power coefficient of a propeller of the aircraft to an axial inflow velocity through the propeller as a function of a set of rotor operating parameters; determining the set of rotor operating parameters by sampling an electronic control signal associated with an electric motor actuating the propeller; computing the axial inflow velocity through the propeller based on the set of rotor operating parameters using the rotor model; and determining the airspeed based on the axial inflow velocity.