Optical Encoder Landing Gear Position Sensor
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Solution Overview
Problem
Existing position sensors for landing gear assemblies, such as LVDTs, are bulky and fragile, making them unsuitable for permanent installation on aircraft, which limits their ability to continuously monitor shock-strut stroke characteristics during the service life of the aircraft.
Innovation Solution
A position sensor system comprising a cylinder, a piston with an optical pattern, and a scanner that optically detects the pattern as the piston translates within the cylinder, communicating data to a microprocessor for conversion into movement quantities, allowing for continuous monitoring of shock-strut characteristics without the need for bulky equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If LVDT (linear variable differential transformer) is used for position sensing, then measurement capability is provided, but device size increases and fragility increases
Solution Approach 1:
The patent replaces the mechanical LVDT sensing system with an optical encoding system. A patterned surface (optical encoder) is attached to the piston, and an optical sensor scans the pattern to determine piston position. This substitution eliminates the bulky mechanical transformer components while maintaining measurement precision, directly resolving the contradiction between measurement capability and device size.
Solution Approach 2:
The patent creates an optical copy or representation of position information through the patterned surface on the piston. Instead of using a complex mechanical transformer to directly measure position, the system encodes position information into a visual pattern that can be scanned by a lightweight optical sensor, reducing sensor size while preserving measurement functionality.
2Measurement precision
If LVDT is used for position sensing, then measurement capability is provided, but device fragility increases
Solution Approach 1:
The patent replaces the fragile mechanical LVDT components with a robust optical encoding system. The patterned surface is simply attached to the piston, and the optical sensor reads the pattern without mechanical contact or complex internal mechanisms, significantly improving reliability and resistance to vibration and shock in the landing gear environment.
Solution Approach 2:
The patterned surface can be considered a simple, replaceable component that is easier and cheaper to replace than a damaged LVDT. The optical sensor system is more rugged and less prone to damage, reducing maintenance needs and improving overall system reliability for permanent installation.
3Measurement precision
If LVDT is used for monitoring, then shock-strut characteristics can be measured, but permanent installation is prevented
Solution Approach 1:
The patent replaces the bulky LVDT with a compact optical encoding system that can be permanently installed within the landing gear assembly. The patterned surface attaches to the piston, and the optical sensor mounts to the cylinder, creating a space-efficient solution suitable for permanent aerospace installation.
Solution Approach 2:
The patent transitions from a three-dimensional mechanical transformer structure to a two-dimensional optical pattern on the piston surface. This dimensional reduction allows the sensing system to fit within the constrained space of the landing gear cylinder-piston assembly, enabling permanent installation where LVDT would not fit.
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 permanent installation on aircraft, providing precise and reliable monitoring of landing gear components, including shock-strut stroke, with a compact and robust sensor system that can detect both linear and angular displacements, enhancing diagnostic capabilities and maintenance insights.
Implementation Method 1
a scanner operatively coupled to the cylinder and positioned to optically detect the pattern during translation of the piston
Data Source
AI summary
A position sensor system for a landing gear assembly includes a cylinder operatively coupled to an aircraft. Also included is a piston configured to translate within the cylinder. Further included is a pattern disposed on an outer surface of the piston. Yet further included is a scanner operatively coupled to the cylinder and positioned to optically detect the pattern during translation of the piston. Also included is a microprocessor in operative communication with the scanner and configured to receive data from the scanner for conversion to a quantity of movement of the piston relative to the cylinder.