Linear Resonant Actuator Frequency Modulation for Haptic Realism
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Solution Overview
Problem
Existing haptic feedback systems for touch screens and capacitive buttons struggle to simulate the feel of a conventional push button effectively, requiring multiple large actuators and consuming significant space and energy, while vibrotactile effects often fail to resemble real buttons to a satisfactory degree.
Innovation Solution
A method using an AC driving signal to control a linear resonant actuator, varying its frequency and amplitude over time to mimic the sensation of a mechanical button, with specific segments and amplitude changes to enhance the perception of softness and realism, implemented in a device with standard hardware components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple vibrating actuators or large actuators are used to simulate conventional push button, then the haptic realism is improved, but the space required and device complexity increase considerably
Solution Approach 1:
The patent applies parameter changes by dynamically varying the driving frequency of a single linear resonant actuator through three distinct time segments: a first segment at a first frequency, a second segment at a second frequency (different from the first), and a third segment at a third frequency. This temporal variation in frequency parameters enables a single actuator to simulate the complex haptic response of multiple actuators or large mechanical buttons, resolving the contradiction between haptic realism and device complexity.
Solution Approach 2:
The patent implements dynamics by making the actuator's operating characteristics time-dependent through sequential frequency changes. The controller dynamically adjusts the drive frequency based on the operational phase, transitioning from an initial frequency to a different frequency and then to a final frequency. This dynamic adaptation allows the system to simulate the progressive compression and feedback sensations of mechanical buttons using a single actuator, thereby reducing complexity while maintaining realism.
2Manufacturing precision
If multiple vibrating actuators are used to simulate conventional push button, then the haptic realism is improved, but the space required inside the device increases
Solution Approach 1:
The patent merges the functions of multiple actuators into a single linear resonant actuator by using temporal frequency modulation. Instead of requiring spatial arrangement of multiple actuators to create different haptic phases, the system combines all necessary haptic information into one actuator and separates it temporally through frequency switching. This merging approach maintains the haptic realism of multi-actuator systems while reducing the physical volume required to the size of a single compact LRA.
3Use of energy by moving object
If conventional drive patterns are used for linear resonant actuators, then the energy consumption is reduced, but the haptic effect does not resemble conventional push buttons to a satisfactory degree
Solution Approach 1:
The patent applies periodic action through the sequential, repeating frequency variation pattern across three time segments. Each segment uses a specific frequency optimized for its functional purpose: the first frequency for initial response, the second frequency for peak compression sensation, and the third frequency for release. This periodic frequency modulation creates a complete haptic cycle that resembles mechanical button compression and release, achieving satisfactory realism while maintaining efficient energy consumption through resonant operation at each phase.
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 method effectively simulates the feel of a real mechanical button, reducing the need for multiple actuators and energy consumption, while providing a more realistic haptic impression compared to prior art, suitable for various consumer electronics.
Implementation Method 1
A linear resonant actuator comprises a voice coil pressing against a moving magnetic mass connected to a spring. The voice coil is driven by an electrical driving signal in order to produce an oscillating force along a single axis
Implementation Method 2
a moving magnetic mass connected to a spring
Data Source
AI summary
The novel linear resonance actuator driving pattern embodied by the AC driving signal waveform may have an all positive (or all negative) actuation, starting oscillations with a first frequency just under the resonance frequency of the linear resonance actuator driving in a first time segment of the drive period. In the first time segment, the amplitude of the AC driving signal also reaches a local maximum. The frequency is then increased to the resonance frequency in a second time segment longer than the first time segment. In the second time segment, the amplitude reaches an overall peak amplitude. Then, the driving frequency along with the amplitude is gradually reduced in a third time segment longer than the second time segment.