Opposing Van der Waals Adhesive Pads for Controlled Space Gripping

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Solution Overview

Problem

Existing adhesive technologies lack effective control over adhesion forces and are not suitable for diverse surface types, including flexible and curved surfaces, especially in vacuum environments like space.

Innovation Solution

The development of grippers with opposing van der Waals adhesive pads, where mechanical forces are applied to control the adhesion by bending and compressing fibers against surfaces, allowing for ON/OFF activation and omnidirectional anchoring through van der Waals forces, similar to gecko toes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional adhesive technologies are used, then adhesion can be achieved on surfaces, but effective control over adhesion forces is lacking and they are not suitable for diverse surface types including flexible and curved surfaces

Engineering Contradiction:

Improveadaptability to diverse surface typesVSAvoidcontrol over adhesion forces

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The adhesive pads incorporate flexible fibers that can dynamically adapt their configuration to match diverse surface geometries. The fibers bend and conform to curved and flexible surfaces, enabling the adhesive to maintain effective contact across varied topographies while allowing mechanical control over adhesion activation and deactivation

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system enables control over adhesion forces by changing the physical state and configuration of the adhesive fibers. Mechanical actuation changes the contact area and compression of fibers, thereby modulating the van der Waals forces to achieve desired adhesion levels on different surface types

Inventive Principle:

Principle #35Parameter changes

2Force

If strong adhesion is achieved through fiber compression, then controlled adhesion with adjustable force levels is enabled, but device complexity increases due to mechanical supporting structures and actuating elements

Engineering Contradiction:

Improveadhesion force controlVSAvoidmechanical supporting structure complexity

Core Design Contradiction:

ForceVSDevice complexity

Solution Approach 1:

The adhesive system is divided into multiple discrete pads, each with its own fiber array. This segmentation allows independent control of adhesion at each pad location while distributing the mechanical loads across multiple elements, reducing the complexity burden on any single structural component

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The flexible fibers possess inherent elasticity and self-compression capabilities. When actuated, the fibers automatically compress against the surface and maintain contact through their own elastic recovery, reducing the need for complex external mechanical structures to maintain adhesion pressure

Inventive Principle:

Principle #25Self-service

3Reliability

If van der Waals forces are used for adhesion, then adhesion works in vacuum environments like space, but the adhesion force may be insufficient for heavy loads without mechanical reinforcement

Engineering Contradiction:

Improveadhesion reliability in vacuumVSAvoidload-bearing adhesion strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The adhesive system combines soft, compliant fiber materials that generate van der Waals forces with rigid mechanical supporting structures. This composite approach allows the soft fibers to provide reliable vacuum-compatible adhesion while the rigid framework supplies the structural strength needed to support heavy loads

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The mechanical supporting structure acts as a counterbalancing element that compensates for the relatively low magnitude of van der Waals forces. The rigid structure provides the necessary load-bearing capacity to support heavy payloads while the adhesive fibers ensure reliable attachment in vacuum environments

Inventive Principle:

Principle #8Anti-weight (Counterweight)

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 strong, controlled adhesion on various surfaces, including flexible and curved ones, with adjustable force levels up to 75 kPa, and maintains adhesion under multiple directional forces, suitable for applications in space such as attaching robots to spacecraft.

Implementation Method 1

the plurality of fibers is configured to bend and compress against a surface external to the structure to enable adhesion through van der Waals forces

Methodology Applied

Scientific Effectvan der Waals forces: Van der Waals Force

Data Source

PatentUS9517610B2Grippers based on opposing van der Waals adhesive pads

Publication Date: 2016.12.13 UNITED STATES OF AMERICA AS REPRESENTED BY THE ADMINISTRATOR NAT AERONAUTICS & SPACE ADMINISTRATION

AI summary

Novel gripping structures based on van der Waals adhesive forces are disclosed. Pads covered with fibers can be activated in pairs by opposite forces, thereby enabling control of the adhesive force in an ON or OFF state. Pads can be used in groups, each comprising a group of opposite pads. The adhesive structures enable anchoring forces that can resist adverse forces from different directions. The adhesive structures can be used to enable the operation of robots on surfaces of space vehicles.