Haptic Actuator with Wrap-Around Coils and Nested Magnet
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Solution Overview
Problem
Existing haptic actuators face challenges in reducing size while maintaining efficiency and actuation force, with size reductions in one axis leading to inefficiencies and increased non-linearity, which affects performance and control complexity.
Innovation Solution
A haptic actuator design featuring a housing with wrap-around coils, non-ferromagnetic masses, and a permanent magnet with specific alignment within the coils, allowing for reciprocal movement and improved magnetic flux distribution, enabling a more compact and efficient haptic feedback mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the haptic actuator size is reduced in one axis, then the device becomes more compact, but efficiency decreases and non-linearity increases
Solution Approach 1:
The patent transitions from a traditional linear coil arrangement to a wrap-around coil configuration that utilizes three-dimensional space more effectively. The coils wrap around the permanent magnet assembly, allowing the magnetic field to be generated in multiple directions and dimensions, thereby maintaining actuation efficiency while reducing the overall footprint of the device.
Solution Approach 2:
The permanent magnet is positioned within the passageways formed by the wrap-around coils, creating a nested configuration where the magnet is embedded in the coil structure. This nesting allows for compact integration of components while maintaining optimal magnetic coupling and field distribution, improving efficiency despite size reduction.
2Volume of moving object
If the haptic actuator size is reduced in one axis, then the device becomes more compact, but non-linearity increases affecting performance
Solution Approach 1:
The wrap-around coils are positioned to create localized magnetic field zones that are optimized for different regions of the permanent magnet. This local optimization of magnetic field distribution ensures uniform force generation across the magnet's surface, reducing non-linearity and improving performance consistency even in a compact configuration.
Solution Approach 2:
The flexure-mounted permanent magnet assembly allows for dynamic positioning and reciprocal movement within the coil passageways. This dynamic capability enables the system to maintain optimal magnetic coupling during operation, compensating for dimensional constraints and reducing non-linear effects through adaptive positioning.
3Ease of manufacture
If the permanent magnet is positioned outside the coil passageways, then manufacturing is simpler, but actuation force per unit volume decreases
Solution Approach 1:
The permanent magnet is nested within the wrap-around coil passageways, with the magnet's ends positioned inside the coil windings. This nested arrangement maximizes the interaction between the magnetic field and the coil conductors, generating higher actuation force per unit volume while maintaining a compact form factor.
Solution Approach 2:
The wrap-around coil configuration creates a three-dimensional magnetic field distribution that envelops the permanent magnet from multiple directions. This multi-dimensional field generation increases the effective magnetic coupling and actuation force density compared to traditional planar coil arrangements.
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 design achieves increased actuation force per unit volume and reduced non-linearity, allowing for smaller dimensions without sacrificing performance, and improves efficiency by over 12% compared to prior approaches.
Implementation Method 1
a permanent magnet having first and second ends coupled to respective ones of the first and second masses. The haptic actuator may also include first and second flexures mounting respective first and second masses to the respective first and second ends of the housing so that the field member is reciprocally movable within the passageways of the first and second coils responsive to powering the first and second coils
Implementation Method 2
The housing may include ferromagnetic material, for example.
Data Source
AI summary
A haptic actuator may include a housing having opposing first and second ends and first and second coils carried by the housing adjacent respective first and second ends thereof. Each coil may have a respective passageway therethrough. The actuator may include a field member including first and second masses adjacent respective first and second ends of the housing, and a permanent magnet having first and second ends coupled to respective ones of the first and second masses. The actuator may also include first and second flexures mounting respective first and second masses to the respective first and second ends of the housing so that the field member is reciprocally movable within the passageways of the coils responsive to powering the coils and so that the ends of the permanent magnet are within respective passageways of the coils when the coils are unpowered.