Coupled-Resonance Haptic Structure for Low-Frequency Force Output
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Solution Overview
Problem
Conventional haptic devices face challenges in providing adequate force and low-frequency vibrations without compromising local stiffness or using multiple actuators, leading to a need for decoupling displacement, stiffness, and frequency of resonance while maintaining a small form factor.
Innovation Solution
A haptic device design featuring a stiff base structure coupled with a compliant secondary region and a heavy mass, allowing for resonant amplification of displacement at low frequencies, using materials like Polybutylene Terephthalate and metals, and employing structures such as cantilevers, spiral patterns, and elastomeric components to achieve enhanced vibro-tactile feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the stiffness of the touch area is reduced to amplify displacement, then displacement is improved, but haptic feedback uniformity and perceptibility deteriorate
Solution Approach 1:
The patent applies resonant vibration to amplify displacement at specific frequencies. The haptic device is designed to resonate at tuned frequencies, allowing large displacement amplitudes without reducing structural stiffness. This resolves the contradiction by using dynamic vibration rather than static compliance to achieve displacement amplification while maintaining feedback uniformity.
Solution Approach 2:
The patent changes the operational parameters by tuning the resonant frequency of the haptic device. By adjusting the stiffness and mass distribution to achieve specific resonant frequencies, the system can amplify displacement at those frequencies while maintaining overall structural integrity and uniform feedback characteristics.
2Force
If multiple actuators are used to amplify forces, then force output is improved, but device cost and size increase
Solution Approach 1:
The patent uses resonant amplification with a single actuator to achieve high force output. By operating at the resonant frequency of the haptic structure, a small actuator can generate large amplitude vibrations and significant haptic forces, eliminating the need for multiple actuators and reducing device complexity.
Solution Approach 2:
The patent exploits dynamic resonance behavior to amplify the output of a single actuator. The haptic device is designed with specific mass and stiffness distributions that create resonant modes, allowing one actuator to produce forces comparable to or exceeding what would require multiple actuators operating in static or non-resonant conditions.
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 solution enables significant displacement and force amplification at low frequencies, maintaining high stiffness and a small form factor, effectively addressing the limitations of conventional haptic devices by tuning resonance frequencies for human perception.
Implementation Method 1
application by the actuator of a resonance frequency to the first structure can cause the first structure and the second structure to resonate in phase and displace the local mass
Data Source
AI summary
A haptic device with coupled resonance at tunable frequencies includes an actuator, a first structure coupled to the actuator, a second structure coupled to the first structure and separate from the actuator, and at least one local mass coupled to the first or second structure; the first and second structure having resonance such that application by the actuator of a resonance frequency to the first structure causes the first and second structures to resonate in phase and displace the local mass. A method of forming a haptic device includes coupling an actuator to a first structure, coupling the first structure to a second structure, locating a mass on at least one of the first or second structures, and configuring the actuator to, upon activation, excite the first structure at a resonance frequency of the haptic device such that the first and second structures resonate in phase and displace the mass.