Soft Crawling Robot With Distributed Nanowire Thermal Actuation

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Solution Overview

Problem

Existing soft robots face challenges in achieving efficient bidirectional locomotion and passing through confined spaces with complex actuation methods requiring high voltages and multiple actuators, limiting their versatility and energy efficiency.

Innovation Solution

A caterpillar-inspired soft crawling robot using a bimorph structure composed of a liquid crystal elastomer (LCE) ribbon and a nanowire composite film with silver nanowires (AgNWs) for programmable thermal actuation, enabling bidirectional locomotion through distributed heating patterns and simple control of local curvature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If complex actuation methods with high voltages and multiple actuators are used, then bidirectional locomotion capability is achieved, but energy consumption increases and device complexity increases

Engineering Contradiction:

Improvebidirectional locomotion capabilityVSAvoidenergy consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The actuator is divided into multiple independent heating zones along its length, each controlled by separate conductive channels. This segmentation allows different segments to be activated independently, enabling bidirectional locomotion through localized thermal expansion rather than requiring multiple full actuators, thus reducing energy consumption while maintaining versatility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent utilizes thermal expansion parameter changes in the bimorph structure. By applying voltage to specific conductive channels, localized heating causes differential thermal expansion between the two layers of the bimorph actuator, generating bending motion. This parameter-based control achieves bidirectional locomotion with low voltage and energy consumption.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If multiple actuators and high voltages are used for soft robot locomotion, then complex actuation control is achieved, but device complexity increases

Engineering Contradiction:

Improveactuation control capabilityVSAvoidactuator quantity and control system

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The bimorph actuator with distributed conductive channels serves multiple functions: it can generate bending motion in multiple directions, control locomotion speed, and achieve bidirectional movement all through a single integrated structure. This universal design eliminates the need for multiple separate actuators and complex control systems, reducing device complexity while maintaining full actuation control capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent replaces traditional mechanical actuation systems with multiple motors and linkages with a thermal-field-based bimorph actuator. By using thermal expansion to generate mechanical bending motion, the system achieves complex locomotion control through simple electrical voltage application to different conductive channels, significantly reducing mechanical complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If distributed heating patterns are applied to bimorph structure, then local curvature control is achieved, but manufacturing precision requirements increase

Engineering Contradiction:

Improvelocal curvature controlVSAvoidnanowire network patterning precision

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The nanowire composite film is designed with spatially varying properties: different regions contain nanowires with different orientations and densities, creating localized conductive channels with specific thermal expansion characteristics. This local quality variation enables precise control of curvature at different positions along the actuator while using standard fabrication techniques, balancing manufacturing feasibility with operational precision.

Inventive Principle:

Principle #3Local quality

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 robot achieves efficient bidirectional locomotion with low voltage and energy consumption, capable of passing through narrow gaps, offering a versatile and efficient solution for complex environments.

Implementation Method 1

energizing a defined conductive channel produces out-of-plane deformation

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

bimorph structure comprising: a liquid crystal elastomer (LCE) ribbon; and a nanowire composite film disposed on a side of the LCE ribbon

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS20250296645A1Caterpillar-inspired soft crawling robot with distributed programmable thermal actuation

Publication Date: 2025.09.25 NORTH CAROLINA STATE UNIV

AI summary

Various examples are provided related to soft crawling robots. In one example, a robot includes a bimorph structure including a liquid crystal elastomer (LCE) ribbon and a nanowire composite film; and electrical connections for coupling the nanowire network to a controlled low voltage source. The nanowire composite film includes a nanowire network forming conductive channels embedded below a surface of the nanowire composite film. Energizing a defined conductive channel can produce out-of-plane deformation in a portion of the bimorph structure to induce directional locomotion of the robot.