A 4D-Printing Inverse Design Strategy for Micromachines with Customized Shape-Morphing

Area of Science:

• Materials Science
• Robotics
• Microengineering

Background:

• Active heterostructures with smart materials offer programmable deformation in response to stimuli.
• 4D printing with two-photon polymerization allows microscale material definition but challenges customized micromachine design.
• Achieving precise shape morphing in microscale machines requires advanced design strategies.

Purpose of the Study:

• To propose a reverse design strategy for guiding the structural design of biomimetic micromachines.
• To develop a reverse design algorithm based on the Timoshenko model for microscale shape morphing.
• To demonstrate the capability of the proposed method in creating functional bionic microrobots.

Main Methods:

• A reverse design strategy utilizing multi-material stepwise 4D printing was developed.
• A reverse design algorithm inspired by the piecewise constant curvature model and based on the Timoshenko model was created.
• The algorithm approximates 2D features to a constant-curvature model and determines material distribution for printing.

Main Results:

• Three biomimetic Chinese 'Long' (dragons) were designed and successfully deformed to customized shapes.
• A microcrawler capable of imitating an inchworm gait was fabricated using the developed method.
• The strategy proved effective in achieving predetermined functions through shape design of bionic soft microrobots.

Conclusions:

• The proposed reverse design strategy and algorithm are efficient for designing bionic soft microrobots.
• This method enables precise control over shape morphing and functionality at the microscale.
• The approach facilitates the creation of customized micromachines with complex behaviors.