Propeller Torque and Thrust Control via Electronic Pitch Adjustment
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Solution Overview
Problem
Traditional aircraft propellers, whether fixed-pitch or constant speed, face inefficiencies and structural limitations due to their mechanical complexity and weight, particularly when operating under varying flight conditions, and lack effective electronic control systems to manage torque and thrust within safe limits.
Innovation Solution
A processor-based system that receives signals for commanded pitch, propeller speed, and air density to estimate torque and thrust, calculates error values, and adjusts pitch commands to maintain constant torque and thrust within predefined limits, using a full authority engine controller to govern propeller speed and prevent over-torquing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If constant speed propellers are used to maintain desired propeller speed and maximize engine performance, then engine efficiency is improved, but mechanical complexity and weight increase due to required mechanical parts
Solution Approach 1:
The patent replaces mechanical constant speed propeller systems with an electronic control system that uses a processor to receive signals about propeller speed and commanded pitch, estimate torque and thrust, and adjust pitch commands electronically. This substitution eliminates the need for complex mechanical parts while maintaining the ability to control propeller speed for optimal engine efficiency.
Solution Approach 2:
The system dynamically adjusts propeller pitch parameters based on real-time conditions by receiving signals indicative of propeller rotational speed and commanded pitch, estimating torque and thrust parameters, and modifying pitch commands to maintain desired propeller speed. This allows the propeller to adapt to varying flight conditions without mechanical complexity.
2Adaptability or versatility
If variable-pitch propellers are used to adapt to varying flight conditions, then adaptability is improved, but structural limits of the airframe may be exceeded when operated in off-design conditions
Solution Approach 1:
The patent implements a feedback control system where the processor receives signals about actual propeller rotational speed and commanded pitch, estimates the resulting torque and thrust, compares these estimates to safe operating limits, and adjusts pitch commands accordingly. This feedback mechanism ensures the propeller operates within structural limits while adapting to varying flight conditions.
Solution Approach 2:
The system takes preliminary protective action by estimating torque and thrust before executing pitch commands that could exceed structural limits. The processor determines information about error values between desired and actual torque, and adjusts pitch commands in advance to prevent over-torquing or exceeding airframe structural limits during off-design operations.
3Reliability
If electronic control systems are added to manage torque and thrust limits, then reliability is improved by preventing over-torquing, but device complexity increases
Solution Approach 1:
The patent employs a multi-functional processor-based control system that simultaneously performs multiple tasks: receiving commanded pitch signals, sensing propeller rotational speed, estimating torque and thrust, calculating error values, and generating corrected pitch commands. This universal controller consolidates what could be multiple separate systems into a single integrated unit, improving reliability while minimizing the increase in device complexity.
Data Source
AI summary
A method for controlling a propeller of an aircraft, comprises receiving, with a processor, one or more signals indicative of commanded collective pitch of the propeller; receiving, with the processor, one or more sensed signals indicative of propeller axial speed, propeller rotational speed, and air density; estimating, with the processor, a propeller torque and propeller thrust from one or more of the propeller axial speed, the propeller rotational speed, and the air density; determining, with the processor, information indicative of an error value between a desired torque and a measured torque in the propeller; determining, with the processor, information indicative of a corrected pitch command in response to the determining of the error value; combining, with the processor, the corrected pitch command with the propeller rotational speed into an adjustment solution; providing, with the processor, the propeller with the adjustment solution.