Electrostatic Clutch for Wearable Robotics Energy Recycling
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Solution Overview
Problem
Traditional clutches used in robotic systems, such as exoskeletons, face challenges with weight and energy efficiency due to continuous power requirements, leading to significant metabolic and weight penalties, particularly in wearable devices where energy recycling is needed to reduce energy consumption.
Innovation Solution
A lightweight, micron-thickness electrostatic clutch system using electrodes made of aluminum-sputtered biaxially-oriented polyethylene terephthalate with a dielectric layer, allowing for low-power operation and energy recycling by controlling electrostatic forces, enabling variable stiffness and force generation with minimal control energy input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If electromagnetic clutches are used, then fast activation is achieved, but continuous electrical power is required and weight increases
Solution Approach 1:
The patent replaces electromagnetic actuation with electrostatic actuation. The electrostatic clutch uses electrostatic forces generated by voltage applied to electrodes separated by a dielectric gap to engage and disengage the clutch, eliminating the need for continuous electromagnetic fields and reducing power consumption while maintaining fast activation response
Solution Approach 2:
The patent changes the actuation mechanism from electromagnetic to electrostatic, fundamentally altering the physical parameter space. By using voltage-controlled electrostatic forces instead of current-driven electromagnetic forces, the system achieves fast activation with minimal continuous power consumption
2Force
If magnetorheological clutches are used, then large torques are produced, but weight increases and continuous power is required
Solution Approach 1:
The patent replaces magnetorheological fluid-based torque transmission with electrostatically-controlled mechanical engagement. The electrostatic clutch uses voltage-controlled electrostatic forces to engage friction surfaces or mechanical elements, achieving torque transmission without heavy magnets, fluid reservoirs, or continuous power requirements
Solution Approach 2:
The patent extracts and eliminates the heavy components associated with magnetorheological clutches, such as large magnets, fluid containment structures, and continuous power supply systems. The electrostatic clutch achieves comparable torque with minimal components and no continuous power
3Adaptability or versatility
If traditional clutches with continuous power requirements are used in wearable devices, then functionality is maintained, but metabolic cost and weight penalty increase significantly
Solution Approach 1:
The patent replaces power-consuming clutch mechanisms with electrostatic clutches that require minimal power. The voltage-controlled electrostatic engagement provides the same clutch functionality without continuous power, reducing the metabolic cost for wearable devices that rely on battery power or human energy
4Use of energy by moving object
If mechanical latches are used, then no energy is required to stay active, but they only engage and disengage under special conditions
Solution Approach 1:
The patent replaces mechanically-limited latches with electrostatically-controlled clutches. The electrostatic clutch uses voltage signals to precisely control engagement and disengagement, providing programmable and adaptable control beyond the fixed mechanical conditions of traditional latches, while maintaining zero continuous power consumption
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 electrostatic clutch system significantly improves energy efficiency and controllability in robotic systems, allowing for dramatic reductions in weight and power consumption while enabling energy recycling and variable torque input/output, enhancing the performance of wearable robotic devices.
Implementation Method 1
Electrostatic forces can be developed by applying a voltage to a set of electrodes separated by a gap. When a voltage is applied, positive and negative electrical charges develop, causing an attraction between the adjacent electrodes
Implementation Method 2
the gap is maintained by a layer of dielectric material deposited on the electrode
Data Source
AI summary
An electrostatic clutch is described comprising a plurality of micron-scale thickness electrodes, adjacent electrodes being separated by a thin film of dielectric material. A power source and controller apply a voltage across two electrodes, causing an electrostatic force to develop. When engaged, a force can be transferred through the clutch. A tensioning device maintains the alignment of the clutch when the electrodes are disengaged, but permits movement in at least one direction. In some embodiments, multiple clutches are connected to an output to provide variable force control and a broad range of torque input and output values. Moreover, the clutch can be used as an energy-recycling actuator that captures mechanical energy from negative work movements, and returns energy during positive work movements.