Aircraft Wheel Speed Sensor Using Electromagnetic Induction
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Solution Overview
Problem
Conventional aircraft wheel speed sensors face challenges in detecting low wheel speeds reliably and often require permanent magnets and multiple wires, leading to inefficiencies and increased complexity.
Innovation Solution
A two-wire wheel speed sensor system using an electro-mechanical system with a stator and rotor that generates a modulated current signal based on aircraft wheel rotation, independent of permanent magnets, allowing for robust speed detection down to nearly zero velocity with fewer wires and less electrical hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional aircraft wheel speed sensors use permanent magnets and multiple wires, then they can detect wheel speed, but the device complexity and wire quantity increase
Solution Approach 1:
The patent extracts and eliminates permanent magnets from the sensor structure, replacing them with an electromagnetic coil system. This removal of unnecessary components simplifies the overall device structure while maintaining the essential function of wheel speed detection through electromagnetic induction principles.
Solution Approach 2:
The two-wire system serves multiple functions simultaneously: it provides both power supply and signal transmission, eliminating the need for separate wiring for each function. This multi-functionality reduces wire quantity and simplifies the electrical connection system while maintaining reliable operation.
2Reliability
If conventional sensors operate at low wheel speeds, then they can detect speed down to zero, but signal amplitude reduction occurs
Solution Approach 1:
The patent utilizes the mechanical rotation of the wheel and rotor as a vibrational input that modulates the electromagnetic field. This mechanical vibration approach ensures that even at very low speeds including zero, the physical movement generates detectable electromagnetic signals without amplitude degradation.
Solution Approach 2:
The patent replaces traditional magnetic field-based detection with an electromagnetic induction system that uses coil windings and electrical excitation. This substitution eliminates the signal amplitude reduction problem inherent in permanent magnet systems at low speeds, as the electromagnetic system maintains consistent signal output across the entire speed range.
3Adaptability or versatility
If permanent magnets are used in the sensor, then magnetic field detection is achieved, but the sensor requires more electrical hardware and becomes less adaptable
Solution Approach 1:
The patent removes permanent magnets from the sensor assembly, reducing the quantity of electrical hardware and materials required. This extraction simplifies the bill of materials and reduces the overall hardware footprint while maintaining detection functionality through the electromagnetic coil system.
Solution Approach 2:
The electromagnetic coil system serves multiple purposes: it generates the magnetic field, detects rotor position, and provides speed information. This multi-functional approach increases adaptability to different applications and reduces the need for additional specialized components.
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
The system provides a robust speed signal that can detect lower wheel speeds effectively and operates across a wide range of velocities without signal amplitude reduction, suitable for harsh environments and adaptable for various applications.
Implementation Method 1
The stator winding is configured to render a modulated current signal on the pair of conductors in response movement of the rotor. The modulated current signal has a frequency that is dependent upon the rotational speed of the aircraft wheel.
Data Source
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Figure 3A~3B
AI summary
An aircraft wheel speed sensor system includes a pair of conductors coupled between an electro-mechanical system and a control system. The control system is configured to apply a carrier voltage signal to the pair of conductors and to detect a modulated current signal on the pair of conductors. The electro-mechanical system includes a stator and a rotor that moves upon rotation of an aircraft wheel. The stator includes a winding disposed about the rotor. The winding is configured to produce the modulated current signal on the pair of conductors in response to movement of the rotor. The modulated current signal has a frequency that is dependent on a rotational speed of the aircraft wheel. The frequency of the modulation is determined by demodulation. The peak amplitude of the modulated signal remains constant over the whole range of detected speeds. The rotor may have a number of major teeth around which the stator coil is wound, each major tooth having a number of minor teeth at the inner periphery. The shape of the teeth provided on the rotor may correspond to the shape of the minor teeth on the stator.