Joystick Lever Position Detection via Eddy Currents
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Solution Overview
Problem
Electromechanical contacting systems in joysticks are prone to wear and tear, and limited in diagnostic capabilities, leading to energy loss and inefficiencies.
Innovation Solution
A control device with a pivotable lever linked to haptic profiles and movable metal flags with variable geometry, using planar coils to generate Eddy currents for directional control and tactile feedback, which maintains energy efficiency by varying the magnetic field in response to lever motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromechanical contacting systems are used in joysticks, then directional control functionality is achieved, but wear and tear occurs over lifetime leading to reduced reliability
Solution Approach 1:
The patent replaces electromechanical contacting systems with a sensor-based detection system using planar coils and metal flags. The sensor electronics detect lever position through electromagnetic coupling between the planar coils and metal flags, eliminating mechanical contact and associated wear, thereby extending service life while maintaining directional control functionality.
Solution Approach 2:
The patent introduces metal flags as intermediary elements that couple the mechanical lever motion to the electromagnetic sensor field. The metal flags move with the lever and modulate the electromagnetic coupling with the planar coils, enabling position detection without direct mechanical contact between sensing components, thus reducing wear.
2Use of energy by moving object
If planar coils are arranged parallel to metal flags for Eddy current generation, then energy efficiency is improved, but magnetic field interference may occur
Solution Approach 1:
The patent employs multiple planar coils arranged in specific orientations (parallel and perpendicular to metal flags) with independent drive signals. By locally optimizing the coil configuration and drive signal phase for each coil, the system maximizes Eddy current generation efficiency while the perpendicular coils provide compensating fields that cancel out unwanted magnetic interference.
Solution Approach 2:
The patent uses periodically alternating drive signals applied to the planar coils to generate oscillating magnetic fields that induce Eddy currents in the metal flags. The periodic nature of the drive signals allows for synchronized detection and enables the system to distinguish between desired position-dependent Eddy current effects and unwanted interference through frequency-based filtering.
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 control device ensures repeatable neutral positioning, provides effective directional control, and minimizes energy loss through the use of Eddy currents, enhancing the durability and diagnostic capabilities of the system.
Implementation Method 1
the planar coils are capable of generating Eddy currents. The variable geometry of the at least two metal flags coupled with the oscillating magnetic field causes the Eddy currents to vary.
Implementation Method 2
The at least one metal flag pair is moveable relative to the coil. The motion of the metal flag however coincides with the tilting motion of the lever.
Data Source
AI summary
A joystick has a lever and a housing. The lever is pivotable around a pivot axis. The joystick has a support plate carrying at least one sensor. The sensor has at least one coil generating a magnetic field. An eddy current is induced into the coil. At least one metal flag is movable relative to the coil. The motion of the metal flag coincides with the tilting motion of the lever.