Stacked Electrostatic Clutch for Wearable Tactile Feedback
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Solution Overview
Problem
Current VR and AR systems lack the ability to provide realistic tactile feedback when users interact with virtual objects, with existing electrostatic clutches requiring large surface areas and high input voltages, making them unsuitable for wearable devices.
Innovation Solution
A compact and lightweight electrostatic clutch with a stacked electrode arrangement and low-power control circuitry that generates strong mechanical resistive forces using a low input voltage, allowing for portable and wireless operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional electrostatic clutch is used to provide tactile feedback, then mechanical resistive force is generated, but the device requires large surface area and high input voltage making it unsuitable for wearable devices
Solution Approach 1:
The patent transitions from a planar electrode arrangement to a three-dimensional stacked configuration. Multiple electrode pairs are arranged in layers along the thickness direction, enabling the generation of strong mechanical resistive forces within a compact volume. This vertical stacking allows the clutch to achieve high force output without requiring large surface area, making it suitable for wearable applications.
Solution Approach 2:
The patent modifies the electrostatic clutch parameters by using multiple thin electrode sheets (e.g., five 0.002-inch sheets) instead of fewer thick sheets. This increases the number of active electrostatic interfaces while reducing individual sheet thickness, thereby generating sufficient resistive force in a compact package. The stacked arrangement of multiple electrode pairs multiplies the force-generating interfaces without proportionally increasing surface area.
2Force
If a conventional electrostatic clutch is used to provide tactile feedback, then mechanical resistive force is generated, but the device requires high input voltage making portable and wireless operation difficult
Solution Approach 1:
The patent changes the operational parameters of the electrostatic clutch by using multiple thin electrode sheets with smaller individual capacitances. This configuration allows the system to achieve the required mechanical force at lower voltages compared to conventional single-pair clutches. The distributed capacitance across multiple stacked pairs reduces the voltage burden on the power supply, enabling portable battery operation.
Solution Approach 2:
The electrostatic clutch is segmented into multiple independent electrode pairs stacked in layers. Each pair contributes a portion of the total resistive force, allowing the system to distribute the electrical load across multiple lower-voltage interfaces. This segmentation enables the use of lower-voltage power sources suitable for wearable devices while maintaining adequate force output through the cumulative effect of multiple pairs.
3Force
If conventional electrostatic clutch design is used, then tactile feedback is provided, but the device size and weight increase preventing wearable application
Solution Approach 1:
The patent employs thin flexible electrode sheets (e.g., 0.002-inch thick) that can be stacked to form the electrostatic clutch. These thin-film structures dramatically reduce the mass of each component while maintaining the necessary mechanical and electrical properties. The flexible nature of these thin sheets also allows them to conform to wearable device geometries, further reducing overall device weight and enabling comfortable wearability.
Solution Approach 2:
By stacking multiple thin electrode sheets in the thickness direction rather than expanding in the planar directions, the patent achieves high force output in a compact, lightweight package. This vertical arrangement minimizes the overall volume and mass of the electrostatic clutch while maintaining adequate force-generating surface area through the cumulative effect of multiple stacked pairs.
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
Enables a lifelike tactile experience in VR and AR environments without the need for external power or control circuits, providing a compact and natural-feeling motion restriction for users interacting with virtual objects.
Implementation Method 1
control circuitry coupled to the electrostatic clutch and configured to generate a control signal to control an electrostatic force between the two or more first electrode sheets and the two or more second electrode sheets
Data Source
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AI summary
One example provides a wireless wearable device including a flexible wearable base configured to be worn at a location of a skeletal joint, an electrostatic clutch including a first electrode, the first electrode having two or more first electrode sheets, each first electrode sheet having a core, a conductive layer formed on the core, and a dielectric coating formed on the conductive layer, and also having a common conductor to which each of the first electrode sheets are connected, and a second electrode having two or more second electrode sheets arranged alternately with the first electrode sheets in a stacked arrangement, a tensioner coupled to the electrostatic clutch, a battery, and control circuitry coupled to the electrostatic clutch and configured to generate a control signal to control an electrostatic force between the two or more first electrode sheets and the two or more second electrode sheets.