Linear Actuator Reactive Force Path for Broadband Haptic Response
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Solution Overview
Problem
Existing linear actuators have limited versatility in frequency response, often exhibiting a narrowband frequency spectrum that fails to accommodate varying drive frequencies, leading to inadequate acceleration responses in haptic applications, and require adjustments in spring constants for different device models, which is costly and inefficient.
Innovation Solution
A linear actuator design featuring a magnetized mass with a reactive force path defined by a combination of springs and magnets, where at least one magnet is positioned transversally adjacent to the displacement path, allowing for a broader frequency response spectrum and enhanced acceleration capabilities by varying the magnetic force based on position, and incorporating a method to shift resonance frequencies by disbalancing energy input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a linear actuator uses a traditional spring-based reactive force path, then the structure is simple and manufacturing is easy, but the frequency response is narrowband and cannot accommodate varying drive frequencies
Solution Approach 1:
The patent combines multiple force-generating elements (springs and magnets) into a unified reactive force path system. The magnets are positioned transversally adjacent to the linear displacement path, creating a composite force field that interacts with the magnetized mass. This merging of mechanical (spring) and magnetic force elements enables broadband frequency response while maintaining a compact structure that does not significantly increase overall device complexity.
Solution Approach 2:
The reactive force path employs a composite approach by integrating magnetic elements with traditional spring mechanisms. The combination of magnetic fields and mechanical springs creates a hybrid force system that provides both the simplicity of mechanical structures and the tunability of magnetic interactions, achieving versatile frequency response characteristics.
2Adaptability or versatility
If the spring constant is adjusted to match different device models, then the acceleration response is optimized for each model, but production costs increase and scalability decreases
Solution Approach 1:
The patent enables parameter tuning through magnetic positioning rather than physical spring replacement. By adjusting the position, strength, or configuration of the transverse magnets, the reactive force characteristics can be optimized for different device models without changing the fundamental spring structure. This magnetic adjustability provides model-specific optimization while maintaining a standardized base design for cost-effective manufacturing.
Solution Approach 2:
The system transitions from static spring constants to dynamically adjustable magnetic forces. The magnetic elements can be repositioned or reconfigured to change the reactive force profile, allowing the same physical structure to adapt to different application requirements. This dynamic adaptability eliminates the need for multiple fixed spring constant variants across different device models.
3Productivity
If magnets are positioned transversally adjacent to the displacement path, then the frequency response spectrum broadens and acceleration capabilities enhance, but the device complexity increases
Solution Approach 1:
The patent introduces transverse magnet positioning perpendicular to the linear displacement path. Instead of placing magnets along the path of motion, they are positioned in a transverse dimension, creating a magnetic field that interacts with the magnetized mass as it moves linearly. This dimensional approach broadens frequency response and enhances acceleration capabilities while using a compact arrangement that minimizes additional structural complexity.
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 a broader frequency response spectrum, enabling significant acceleration at various frequencies, reducing production costs, and improving scalability and reliability by providing a more versatile force response curve that adapts to different drive frequencies without requiring constant adjustments.
Implementation Method 1
at least one magnet configured to interact with the magnetic field of the mass and generate a magnetic force therewith, the amplitude of the magnetic force varying depending of the position of the mass in the linear displacement path
Implementation Method 2
The reactive force path can stem from one or more springs
Data Source
AI summary
A linear actuator comprising a mass movably mounted in a linear displacement path, the mass having a magnetic segment, a drive force generator configured to selectively impart acceleration to the mass in the orientation of the linear displacement path, and a reactive force path generating a return force when the mass is displaced from a rest position. The return force being in the orientation of the linear displacement path and towards the rest position, the amplitude of the return force varying as a function of the position of the mass in the linear displacement path in accordance with a force response curve, the reactive force path including a permanent magnet force element disposed transversally adjacent to the linear displacement path and magnetically coupled with the magnetic segment.