Haptic Actuator Controller Resonant Frequency Detection
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Solution Overview
Problem
Haptic actuators in mobile devices face challenges in accurately determining their resonant frequency due to variations caused by manufacturing tolerances, temperature changes, and device orientation, leading to reduced haptic feedback efficiency and increased power consumption.
Innovation Solution
A controller for haptic actuators that includes a driver and a frequency detector, allowing the passive detection of the resonant frequency from signals generated by externally applied forces, enabling the adjustment of drive signals to match the resonant frequency without active electrical actuation, thereby improving haptic feedback and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If active electrical actuation is used to determine resonant frequency, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The haptic actuator serves dual purposes: it provides haptic feedback during normal operation and simultaneously measures its own resonant frequency by detecting signals generated during free vibration. This self-service approach eliminates the need for separate measurement actuators and reduces power consumption while maintaining measurement precision.
Solution Approach 2:
Instead of using active electrical actuation to measure resonant frequency, the patent inverts the approach by passively detecting signals generated during free vibration caused by external forces. This inversion transforms a power-consuming active measurement into a power-efficient passive detection process.
2Productivity
If resonant frequency tracking is not implemented, then device complexity is reduced, but haptic feedback efficiency deteriorates
Solution Approach 1:
The controller is designed with multi-functionality, integrating both haptic feedback generation and resonant frequency measurement capabilities within the same hardware components. The driver and detector serve dual purposes, eliminating the need for separate measurement systems and reducing overall device complexity while improving haptic feedback efficiency.
Solution Approach 2:
The patent merges the haptic actuator and measurement detection into a single integrated system. The same actuator that provides haptic feedback also serves as the measurement sensor by detecting signals during free vibration, combining two functions into one component to reduce complexity.
3Measurement precision
If manufacturing tolerances and temperature variations are not compensated, then device complexity is reduced, but resonant frequency accuracy deteriorates
Solution Approach 1:
The system implements feedback by continuously measuring the resonant frequency through detected signals and using this information to adjust drive signals. This feedback mechanism compensates for manufacturing tolerances and temperature variations, maintaining resonant frequency accuracy without requiring complex pre-calibration systems.
Solution Approach 2:
The patent utilizes parameter changes in the detected signal characteristics (frequency, amplitude) during free vibration to determine resonant frequency. By monitoring these natural parameter variations, the system compensates for environmental factors and manufacturing tolerances without adding complex adjustment mechanisms.
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 accurate tracking of resonant frequency variations, enhancing haptic feedback quality and reducing power consumption by allowing for precise drive signal adjustments, even when the actuator is not actively driven, thus improving the overall performance of haptic actuators in mobile devices.
Implementation Method 1
detect a signal generated on the terminals of the haptic actuator in response to an externally applied force
Data Source
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AI summary
A controller for a haptic actuator is described. The controller includes a driver which has an output configured to be coupled to a linear resonant actuator in a first mode and a frequency detector having an input configured to be coupled to the haptic actuator in a second mode. The frequency detector is configured to detect a signal generated on the terminals of the haptic actuator in response to an externally applied force and to determine a resonant frequency of the haptic actuator from the generated signal.