Haptic Feedback Controller Adjusts Electrode Voltage via Displacement Current
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Solution Overview
Problem
Existing electrovibration-based haptic systems face challenges in providing a consistent haptic experience to users due to variations in the grounding path, which can be affected by factors such as user position, contact with a ground, and electrical properties between the user and the device, leading to inconsistent tactile sensations.
Innovation Solution
A touch-sensitive screen with a set of electrodes and a haptic feedback system that includes a haptic voltage signal generator, current sensing device, and haptic feedback controller, which detects displacement currents from user touch inputs to modify the haptic signal and maintain a consistent haptic experience by adjusting the voltage on the electrodes based on the determined displacement current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If no ground connection is provided, then the device structure remains simple, but the haptic experience becomes inconsistent
Solution Approach 1:
The system measures displacement current as a feedback signal that reflects grounding conditions, then uses this feedback to dynamically adjust the haptic signal amplitude. This closed-loop control compensates for varying grounding paths without requiring explicit ground connections or additional hardware, resolving the contradiction between haptic consistency and device simplicity
Solution Approach 2:
The system uses the existing touch input and electrode structure to generate both the haptic effect and the grounding diagnostic information (displacement current). The same components serve dual purposes: delivering haptic feedback and monitoring grounding conditions, eliminating the need for separate grounding hardware while maintaining consistent haptic experience
2Reliability
If wrist straps are used to ground the user, then consistent haptic experience is achieved, but user convenience deteriorates
Solution Approach 1:
The invention extracts the grounding function from external accessories (wrist straps) and integrates it into the device itself by using the displacement current measurement through existing electrodes. This eliminates the need for additional grounding equipment while maintaining haptic consistency, significantly improving user convenience
3Reliability
If another finger or part of the user's hand must touch the device for grounding, then grounding is achieved, but device usability deteriorates due to restricted holding positions
Solution Approach 1:
The system makes the touch interface universally functional by allowing any touch input to serve dual purposes: both user interaction and grounding path establishment. The displacement current measurement works through any touch point, eliminating the need for specific grounding contact points and allowing users to hold and interact with the device in any comfortable position
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 system effectively stabilizes the modulation of friction force, providing a consistent haptic sensation to users regardless of grounding conditions, ensuring a reliable tactile experience by dynamically controlling the haptic signal strength based on displacement current measurements.
Implementation Method 1
Electrovibration-based haptics may refer to the use of an electrostatic force to provide one or more sensations to a user
Implementation Method 2
modifying the haptic signal based on a displacement current from the touch input to the set of electrodes
Data Source
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AI summary
An apparatus for providing tactile feedback is provided. The apparatus includes a touch-sensitive screen that detects a touch input and a set of electrodes. The apparatus also includes a haptic voltage signal generator that applies a haptic signal to the set of electrodes and modifies the haptic signal based on a displacement current from the touch input to the set of electrodes. The apparatus also includes a haptic feedback controller that determines the displacement current, where the displacement current is an effect of an amplitude of the haptic signal.