Haptic Device Calibration Using Inverse Filtering
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Solution Overview
Problem
Haptic devices in electronic devices often provide inconsistent tactile and audio feedback due to variations in device materials and structure, affecting user experience and consistency over time.
Innovation Solution
A method and system for calibrating haptic devices by determining a scaling factor and using it to generate an input waveform that matches a desired output waveform, incorporating a model that accounts for the haptic device's effects as a linear time-invariant system, and adjusting waveforms to maintain consistent haptic and audio output across devices and over their lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If haptic devices are used to provide tactile and audio feedback, then user interaction capability is improved, but output consistency varies from device to device and over time
Solution Approach 1:
The system performs preliminary calibration by determining device-specific parameters (mass, stiffness, damping coefficients) and pre-computing inverse filter coefficients before actual use. This preliminary characterization allows the system to compensate for device variations and maintain consistent output across different devices and over time.
Solution Approach 2:
The system uses measured device response to compute inverse filters that feed back into the signal processing chain. By continuously applying these inverse filters to input signals, the system compensates for variations in device parameters and maintains reliable output consistency despite changes in device state or aging.
2Ease of manufacture
If device materials and structure vary, then device manufacturing flexibility is improved, but haptic output distortion increases
Solution Approach 1:
The system determines specific physical parameters (mass, stiffness, damping coefficients) for each device through calibration measurements. By adapting the control parameters based on the actual measured characteristics of each device, the system compensates for material and structural variations, allowing manufacturing flexibility while maintaining output precision.
Solution Approach 2:
The system replaces mechanical uniformity with computational compensation. Instead of requiring all devices to have identical mechanical properties, the system uses software-based inverse filtering and adaptive control to achieve consistent output, substituting mechanical precision requirements with computational correction.
3Reliability
If calibration parameters are determined for each device, then output consistency is improved, but calibration time and complexity increase
Solution Approach 1:
The system determines only the essential calibration parameters needed for consistent operation (mass, stiffness, damping coefficients) rather than characterizing all possible device properties. This partial calibration approach achieves sufficient output consistency while minimizing calibration time and complexity.
Data Source
AI summary
Disclosed herein are methods and systems for providing haptic output and audio output on computing devices using the same haptic device and methods for calibrating the same. To produce the haptic and audio output, the computing device receives a profile of a desired output waveform that is to be provided by the haptic device. Using the desired output waveform, an input waveform is generated. Once the input waveform that will produce the desired output waveform is generated, the input waveform may be calibrated to account for various structural components of the haptic device and may also be combined with an audio waveform. The input waveform is then provided to the haptic device.