Programmable actuators show the potential of soft robotics

Researchers at TU Delft have developed highly programmable actuators that, like the human hand, combine soft and hard materials to achieve complex movements. These materials offer great potential for flexible robots that can interact effectively and safely with humans and other delicate objects. Scientists report on their work in Horizons Materials in the July 8 issue.

Soft

"The robots are usually big and heavy. But you also want robots capable of acting with delicacy, for example when handling soft tissues in the human body. The field that studies this issue, soft robotics, is taking off, "says Prof. Amir Zadpoor, who oversaw the research presented in Horizons Materials.

"What you really want is something that looks like the features of the human hand, including soft touch, fast but precise movements, and power." And that's what our programmable materials soft 3D prints strive to achieve.

tunability

Thanks to their soft touch, soft robotics can interact effectively and safely with humans and other delicate objects. Programmable mechanisms are needed to power this new generation of robots. The flexible mechanical metamaterials working on the basis of mechanical instability offer unprecedented functionalities programmed in their architectural structure that make them potentially very promising as flexible mechanisms. "However, the possibilities of developing the mechanical metamaterials proposed so far are very limited," said researcher and first author, Shahram Janbaz.

programmable

"We are now presenting new designs of ultra-programmable mechanical metamaterials in which not only the force and amplitude of actuation, but also the actuation mode could be selected and tuned in a very wide range. We also show some examples of the use of these flexible actuators in robotics, for example as a force switch, kinematic controllers and terminal effector selection, "Janbaz explains.

buckle

"The function is already integrated into the material," explains Zadpoor. "So we had to take a closer look at the phenomenon of buckling, which was once considered the embodiment of design failure, but has been exploited in recent years to develop advanced mechanical metamaterials. However, exploiting the significant potential of buckling materials depends on the resolution of the main limitation of the designs presented so far, namely the limited range of their programmability, we have been able to calculate and predict buckling modes and make the material predisposed to these higher modes. "

3D printing

"We are therefore presenting multimaterial metamaterials driven by buckling and offering high programmability," says Janbaz. "We have combined rational design approaches based on predictive computing models with advanced multi-material additive manufacturing techniques to print 3D cellular materials with arbitrary distributions of soft and hard materials in the central parts and angles. their unit cells For the distribution of material properties as main design parameters, we have developed flexible mechanical metamaterials behaving as mechanisms whose force and amplitude of actuation could be adjusted. "