Active Haptic Trackpad Control with Accelerometer Feedback
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Solution Overview
Problem
Existing trackpads experience variations in haptic response due to manufacturing tolerances, environmental conditions, and mechanical wear, leading to inconsistent user experiences across units and over time.
Innovation Solution
Incorporation of an accelerometer and a microcontroller to measure and adjust the peak-to-peak acceleration of a haptic trackpad, using a closed-loop feedback system to calibrate and control the haptic element, ensuring consistent haptic feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manufacturing tolerances and environmental conditions are not controlled, then device complexity is reduced, but haptic response consistency deteriorates
Solution Approach 1:
The patent implements a closed-loop feedback control system where an accelerometer measures the actual haptic response acceleration, compares it to a target acceleration value, and adjusts the haptic element output accordingly. This feedback mechanism maintains consistent haptic response across manufacturing variations and environmental conditions by continuously monitoring and correcting deviations from the target response.
Solution Approach 2:
The system dynamically adjusts operational parameters (haptic element output strength) based on measured acceleration feedback. By changing the output parameter of the haptic element in response to measured conditions, the system compensates for manufacturing tolerances and environmental variations without requiring precise control during manufacturing.
2Reliability
If an accelerometer and microcontroller are added to measure and adjust acceleration, then haptic feedback consistency is improved, but device complexity increases
Solution Approach 1:
The accelerometer and microcontroller form a feedback control loop that measures actual haptic response and adjusts the haptic element accordingly. This automated feedback system replaces manual calibration processes and maintains consistency without requiring additional user intervention or complex manufacturing controls.
Solution Approach 2:
The system performs self-calibration and self-adjustment using the accelerometer feedback. The microcontroller automatically modifies haptic element output based on measured acceleration, enabling the device to self-correct for manufacturing variations and environmental changes without external intervention.
3Manufacturing precision
If haptic element output is adjusted based on measured acceleration, then manufacturing precision requirements are reduced, but measurement precision requirements increase
Solution Approach 1:
The patent replaces mechanical precision control (tight manufacturing tolerances) with an electronic measurement and control system. Instead of relying on precise mechanical assembly to ensure consistent haptic response, the system uses an accelerometer to measure the actual response and electronically adjusts the haptic element output to compensate for mechanical variations.
Solution Approach 2:
The system transitions from controlling physical assembly parameters to controlling electrical output parameters. By measuring acceleration and adjusting the haptic element's electrical drive signal accordingly, the system achieves consistent haptic response while allowing broader mechanical manufacturing tolerances.
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
Provides a uniform and improved user experience by maintaining consistent haptic feedback across manufacturing runs and the lifespan of trackpads, enhancing the perception of adequate pressure for clicks.
Implementation Method 1
a haptic element fixedly attached to the PCB to selectively oscillate the PCB
Implementation Method 2
an accelerometer fixedly attached to the PCB to measure peak-to-peak acceleration of the oscillation of the PCB
Data Source
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AI summary
Variations in the manufacturing, tolerances, and environmental conditions, for example, of haptic trackpads can cause mechanical properties to vary click-by-click and unit-by-unit. Also, as time goes, mechanical wear or material degradation within each trackpad may change its mechanical properties. All of which may cause the haptic response received by the user to vary across similarly designed trackpads, and also change over time on the same trackpad. This may be interpreted by the user as an indication of low product quality. The following describes in detail haptic trackpads including accelerometers that enable active control and/or calibration. This allows for a more uniform user experience across a manufacturing run of trackpads and/or throughout the projected life of individual trackpads. It is disclosed a trackpad comprising: a printed circuit board (PCB) including a touch interface; a haptic element fixedly attached to the PCB to selectively oscillate the PCB; an accelerometer fixedly attached to the PCB to measure peak-to-peak acceleration of the oscillation of the PCB; and a microcontroller to: compare the measured peak-to-peak acceleration with a target peak-to-peak acceleration of the oscillation of the PCB; and adjust an output of the haptic element to change the measured peak-to-peak acceleration to match the target peak-to-peak acceleration of the oscillation of the PCB.