Aircraft Center of Mass Estimation Using Shock Strut Sensors
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Solution Overview
Problem
Current aircraft systems lack an effective method to accurately estimate the center of mass laterally and longitudinally during various phases of flight, such as takeoff and landing, using shock strut assemblies, which are crucial for safe and efficient operations.
Innovation Solution
A method and system that utilize sensors to measure gas pressure and stroke of shock struts to determine the takeoff and landing phases, allowing for the calculation of the center of mass in a horizontal plane by averaging forces from multiple shock struts, and determining lateral and longitudinal distances from the wheelbase and tread axes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shock strut assemblies are used to manage landing gear energy, then energy transmission to aircraft structure is reduced, but the ability to accurately estimate center of mass and weight is lost
Solution Approach 1:
The shock strut assembly is designed to perform multiple functions: it continues to manage landing gear energy transmission while simultaneously serving as a sensing system for weight and center of mass estimation. The existing shock strut components (piston, fluid chamber, gas spring) are utilized as sensing elements, eliminating the need for separate weighing equipment and enabling dual functionality from a single system.
Solution Approach 2:
The shock strut system uses its own operational parameters (gas pressure, piston stroke position) to provide weight and center of mass information without requiring external sensing equipment. The system serves itself by converting its mechanical operation data into useful weight estimation data, eliminating the need for additional dedicated weighing sensors or systems.
2Measurement precision
If multiple sensors are installed on shock struts to measure pressure and stroke, then center of mass estimation accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The existing shock strut components (piston, fluid chamber, gas spring) are utilized as sensing elements, eliminating the need for separate weighing equipment and enabling dual functionality from a single system.
Solution Approach 2:
Gas pressure sensors and position sensors serve as intermediaries that translate the mechanical state of the shock strut into measurable electrical signals. These sensors mediate between the mechanical compression/stroke events and the computational algorithms that determine weight and center of mass, enabling precise measurement without direct mechanical contact weighing mechanisms.
3Reliability
If weight and center of mass data are collected during takeoff and landing phases, then operational safety is enhanced, but data processing time and complexity increase
Solution Approach 1:
The system continuously monitors shock strut parameters during normal operation and pre-processes the data during takeoff and landing phases before critical decisions are needed. By maintaining readiness and pre-calculating potential weight scenarios during these phases, the system reduces real-time processing delays when safety decisions must be made.
Solution Approach 2:
The system implements continuous feedback loops where sensor data from shock struts is immediately processed and fed back to update weight and center of mass estimates. This real-time feedback mechanism during takeoff and landing phases allows for rapid safety assessments without significant processing delays, as the system is already in a state of active monitoring and calculation.
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 precise estimation of the aircraft's center of mass, enhancing safety and operational efficiency by accurately tracking changes in weight distribution during flight phases.
Implementation Method 1
shock strut assemblies to assist in reducing and managing energy transmitted from landing gear to the structure of an aircraft
Implementation Method 2
a piston that compresses a fluid within a sealed chamber. The fluid typically includes a gas segment and a liquid segment
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A system and various methods for determining a center of mass of an aircraft (10) with a plurality of shock strut assemblies is illustrated. Multiple sensors, including a gas pressure sensor (110), and/or a position sensor (116), may be used to gather data and determine the center of mass of the aircraft. Various methods illustrated herein may evaluate the center of mass relative to a wheelbase axis and a wheel tread axis based on the gathered data.