Soft Pneumatic Actuator Pressure Sensing for 3D Hand Tracking
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Solution Overview
Problem
Existing assistive and rehabilitative devices with soft pneumatic actuators face challenges in accurately controlling and monitoring the movement, strength, and range of motion of body parts, particularly digits of the hand, due to difficulties in tracking three-dimensional position and monitoring underlying strength, and precise control of pressurization and depressurization.
Innovation Solution
The use of a piezoelectric resonant acoustic gas pump that generates and rectifies an acoustic standing wave to provide gas flow, minimizing distortion of the pressure waveform, allowing for precise tracking of body part position and strength monitoring through pressure measurements, and enabling accurate control of the soft pneumatic actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a hydraulic pump is used to actuate soft hydraulic actuators, then the actuators can be controlled to assist and resist movement, but the system becomes complex with multiple components including water reservoir, mechanical switches, and electromagnetic tracking systems
Solution Approach 1:
The patent uses pneumatic actuators instead of hydraulic actuators, replacing water-based systems with gas-based systems. This simplifies the overall system by eliminating the need for water reservoirs and complex hydraulic components while maintaining the ability to control soft actuators for assisting and resisting body part movements.
Solution Approach 2:
The patent replaces mechanical switches and electromagnetic tracking systems with acoustic wave-based sensing and control mechanisms. Acoustic waves are used to detect body part position and movement, eliminating the need for external electromagnetic tracking equipment and complex mechanical control switches.
2Measurement precision
If external electromagnetic tracking systems are used to track hand position, then position information can be obtained, but the system complexity increases and integration with the soft robotic glove becomes difficult
Solution Approach 1:
The patent integrates the tracking function directly into the soft robotic glove by incorporating acoustic sensors and wave generation capabilities within the glove structure itself. This merging of tracking and actuation functions into a single integrated system eliminates the need for separate external electromagnetic tracking equipment.
Solution Approach 2:
The patent replaces external electromagnetic tracking systems with an acoustic-based tracking system that uses sound waves to detect hand position and movement. This acoustic approach is more easily integrated with the soft robotic glove structure and eliminates the complexity of electromagnetic tracking equipment.
3Ease of manufacture
If manual control with mechanical switches is used, then the system is simple to manufacture, but the control precision and responsiveness are limited
Solution Approach 1:
The patent replaces mechanical switches with acoustic wave-based sensing and control mechanisms. Acoustic sensors detect body part position and movement with high precision, and acoustic waves provide responsive control signals, eliminating the limitations of manual mechanical switch control while maintaining manufacturing feasibility.
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 solution provides improved control and monitoring of body part movements by accurately tracking three-dimensional position, determining when to turn the gas pump on or off, and monitoring strength, thereby enhancing the precision and sensitivity of assistive and rehabilitative functions.
Implementation Method 1
a piezoelectric resonant acoustic gas pump that generates and rectifies an acoustic standing wave to provide gas flow
Implementation Method 2
a piezoelectric resonant acoustic gas pump that generates and rectifies an acoustic standing wave
Data Source
AI summary
A method of monitoring a device that includes a soft pneumatic actuator and a gas pump, the soft pneumatic actuator configured to actuate, assist and/or resist a movement of a body part. The method includes measuring the pressure of a fluid in the internal chamber of the soft pneumatic actuator. The pressure measurement or measurements is/are used to estimate anyone or any combination of: the volume of the internal chamber; the three-dimensional position, shape, and/or displacement of the soft pneumatic actuator; and the force delivered by the soft pneumatic actuator.