Electrosensory Vibration Current Control via Impedance Estimation
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Solution Overview
Problem
Current electrosensory vibration systems face limitations in expressing a wide range of haptic effects due to current-limited voltage sources, which restrict the intensity and repetition of tactile sensations, failing to fully utilize the permissible current range as defined by safety standards like IEC 60950-1.
Innovation Solution
A system comprising a powerful voltage source combined with a controller that estimates and adjusts the external load impedance to manage output current, ensuring it stays within safe limits while optimizing haptic effect pulses to enhance tactile perception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current-limited voltage sources are used in electrosensory vibration systems, then safety standards are met, but the intensity and repetition of tactile sensations are restricted
Solution Approach 1:
The system dynamically adjusts the voltage source output based on real-time measurement of actual current flow to the user. The controller modulates the voltage waveform parameters (amplitude, frequency, duty cycle) dynamically, allowing the system to operate at maximum safe current levels rather than being constrained by conservative fixed limits. This enables intensive and repeated haptic effects while maintaining safety compliance through active control.
Solution Approach 2:
The system implements a feedback loop where the actual current flow is measured and used to adjust the voltage source output. The controller receives feedback about the actual current being delivered to the user and modifies subsequent voltage pulses accordingly. This closed-loop control allows the system to fully utilize the permissible current range defined by safety standards, optimizing haptic effect delivery while ensuring safety compliance.
2Object-affected harmful factors
If conservative current limits are applied, then user safety is ensured, but the range of expressible haptic effects is limited
Solution Approach 1:
The system uses dynamic waveform modulation to deliver a wide variety of haptic effects. By varying voltage amplitude, frequency, pulse width, and duty cycle in real-time based on measured current flow, the system can express diverse tactile sensations (vibration, pulse, ripple, texture) while staying within safety limits. This dynamic control provides adaptability across multiple haptic effect types without compromising user safety.
Solution Approach 2:
The system changes multiple electrical parameters of the voltage waveform (amplitude, frequency, pulse duration, duty cycle) to generate different haptic effects. By manipulating these parameters dynamically and measuring the resulting current flow, the system can deliver diverse tactile experiences while ensuring that the actual current delivered to the user remains within safe thresholds defined by standards like IEC 60950-1.
3Device complexity
If fixed voltage output is used, then system simplicity is maintained, but optimization of haptic effect pulses is prevented
Solution Approach 1:
The system incorporates current measurement and feedback control to optimize haptic effect delivery. The controller measures actual current flow and adjusts voltage waveform parameters accordingly, enabling intensive and repeated haptic effects while maintaining safety compliance. This feedback mechanism allows the system to adapt to varying load conditions and user interactions, optimizing performance without requiring overly complex hardware modifications.
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
This approach allows for a broader range of haptic effects with controlled current levels, maintaining safety standards and providing more nuanced tactile experiences by dynamically adjusting the output current based on load impedance estimation.
Implementation Method 1
machines that are configured to facilitate electrosensory vibration, which may also be called electrostatic vibration or electrovibration, including devices configured to provide, via electrosensory vibration, various tactile effects that do not involve mechanical actuation
Implementation Method 2
systems (e.g., apparatus) and methods to facilitate measurement and control (e.g., management) of current flowing from such a device to a user
Data Source
AI summary
In electrosensory vibration technology, a potential difference is formed between a touched surface of a device and a body member of a user, creating an attractive force between the two. To meet industry safety standards, the capability of a corresponding voltage source to drive electrical current may be kept low, and the maximum slew rate with such a voltage source would be accordingly limited. However, such a limit on the slew rate may result in softer haptic effects or lower repetition rates of haptic effects, and the ability of such a device to express a wide range of haptic effects may be reduced compared to a device capable of driving the external load with the maximum current allowed by applicable standards. As a technical means to solve this technical problem, it may be helpful to use a powerful voltage source with a controller to control the outgoing current.