Passive Haptic Magnetic Indexing With Integrated Position Sensing
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Solution Overview
Problem
Existing haptic devices face challenges in simplifying industrial production, achieving a large number of indexed positions, magnetizing magnetic poles with alternating polarity, and reducing magnetic losses that lead to friction and bulkiness, especially when using optical, resistive, or magnetic sensors for position control.
Innovation Solution
A passive haptic device design featuring mechanical members with minimized alternating North/South magnetic poles, integrated position sensors, and magnetized zones structured to produce a variable force without electric coils, using soft ferromagnetic materials and magnetized zones in the same sense to minimize friction and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multipolar assemblies with alternating magnet poles are used to achieve angular indexing, then the number of indexed positions can be increased, but the device complexity and manufacturing difficulty increase significantly
Solution Approach 1:
The patent divides the magnetic indexing system into two separate assemblies: a first assembly with unipolar magnets and a second assembly with alternating polarities. This segmentation allows each assembly to be optimized independently, reducing the manufacturing complexity of individual components while achieving the desired number of indexed positions through their interaction.
Solution Approach 2:
The patent combines two simpler magnetic assemblies (one with unipolar magnets and one with alternating polarities) to achieve the functionality of a complex multipolar assembly. The interaction between these two assemblies produces the required angular indexing positions without requiring any single assembly to be overly complex.
2Difficulty of detecting and measuring
If optical, resistive or magnetic sensors are juxtaposed with the haptic device for position control, then position sensing capability is achieved, but the device becomes bulky and expensive
Solution Approach 1:
The magnetic assemblies serve dual functions: they provide both the haptic feedback force and the position sensing reference. The same magnets that create the tactile indexing effect also generate the magnetic field signature that the magnetometer uses to detect position, eliminating the need for separate sensing components.
Solution Approach 2:
The haptic device uses its own magnetic components to provide position sensing information. The magnetometer detects the magnetic field variations created by the magnetic assemblies, allowing the system to self-monitor its position without requiring external sensors.
3Force
If soft ferromagnetic materials are used in areas with high magnetic induction variation, then magnetic coupling is achieved, but magnetic losses (induced currents, hysteresis) increase causing friction
Solution Approach 1:
The patent removes soft ferromagnetic materials from the air gap areas where magnetic induction varies significantly. By extracting these materials from the high-variation zones, the system reduces magnetic losses from induced currents and hysteresis, thereby reducing friction while maintaining necessary magnetic coupling through the magnetic assemblies.
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
This solution simplifies production, reduces friction, and integrates position sensing without electric energy consumption, enhancing the haptic rendering quality and economic viability of haptic devices.
Implementation Method 1
a force that varies periodically as a function of the relative position of the mechanical members being created by the magnetic interaction between the mechanical members
Implementation Method 2
These variations induce losses of magnetic origin (by induced currents, by hysteresis effect, etc.)
Implementation Method 3
These variations induce losses of magnetic origin (by induced currents, by hysteresis effect, etc.)
Data Source
AI summary
The present disclosure relates to a passive haptic device comprising a mechanical member moving with respect to a second mechanical member, one of the mechanical members having a plurality of magnetized zones spaced periodically according to a pitch P1, the other of the mechanical members having a second plurality of magnetized zones spaced periodically according to a pitch P2, a force that varies periodically as a function of the relative position of the mechanical members being created by the magnetic interaction between the mechanical members, the magnetic interaction varying according to a period Pt, wherein all the magnetized zones of at least one of the mechanical members are magnetized in the same sense.