Negative Pressure Soft Bending Actuator for Safe Gripping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Soft robotic grippers face limitations in maximum grasping force and safety concerns due to high pressure requirements, with existing positive pressure systems risking bursting and requiring puncture-resistant materials, while also having limitations in pump capabilities and material constraints.
Innovation Solution
A soft bending actuator is developed using a stiff layer bonded to a softer layer with interconnected voids, which contracts under negative pressure differential, allowing for bending motion and increased gripping force without the need for high pressure, utilizing a vacuum port for pressure equalization and actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If positive pressure bellows system is used, then grasping force is increased, but safety concerns arise due to risk of bursting high pressure lines
Solution Approach 1:
The patent inverts the conventional positive pressure actuation approach by using negative pressure (vacuum) actuation. Instead of pressurizing the bellows to generate gripping force, the system creates a vacuum within the bellows chamber, causing the elastomeric material to contract and bend, thereby generating gripping force through suction rather than pressure, which eliminates the bursting hazard
Solution Approach 2:
The patent changes the pressure parameter from positive to negative. By operating the bellows system under negative pressure (vacuum conditions) rather than positive pressure, the system achieves the same actuation function while avoiding the safety risks associated with high pressure lines and potential bursting
2Ease of operation
If positive pressure bellows system is used, then actuation is achieved, but pump limitations restrict system performance
Solution Approach 1:
The patent inverts the pressure approach from positive to negative, which fundamentally changes the actuation mechanism. This inversion allows the use of vacuum pumps or evacuator systems that are often more compact, reliable, and easier to control than high-pressure pump systems, thereby reducing device complexity while maintaining ease of operation
3Reliability
If soft robotic gripper is fabricated with tear/puncture resistant material, then safety is improved, but material selection and fabrication complexity increase
Solution Approach 1:
By inverting the pressure approach to use negative pressure actuation, the patent eliminates the need for tear and puncture resistant materials. The vacuum actuation system does not subject the elastomeric bellows to the same high-stress conditions that would require specialized materials, thereby simplifying material selection and fabrication processes while maintaining safety
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 soft robotic gripper achieves a high degree of curvature and increased gripping force, particularly suitable for subsea and light pick-and-place applications, with improved safety and reduced material constraints, while maintaining simplicity in grasping algorithms.
Implementation Method 1
contracts under negative pressure differential, allowing for bending motion
Implementation Method 2
a second layer of a second elastomeric material, said second elastomeric material being relatively compliant
Data Source
AI summary
A soft robotic bending actuator has a stiff layer bonded to a softer layer where the softer layer is a cellular solid with interconnected voids. The softer layer contracts under a negative pressure differential between the internal pressure of the actuator and its environment applied along its axial direction. The contraction results in a bending motion; i.e., an increased curvature away from the stiff layer.