Tiny, Soft Robotic Spider Shows Potential in Biomedical Sphere


Spider robot / Photo by Pixabay.com


The smallest of soft robotic systems typically have a limited degree of freedom, but engineers at Harvard University and Boston University overcame that challenge with their new soft robot.

Their soft robot model has been inspired by the origami paper-folding art and the Australian peacock spider. The robotic design has a scale of millimeters but includes features in the micrometer scale.

“By developing a new hybrid technology that merges three different fabrication techniques, we created a soft robotic spider made only of silicone rubber with 18 degrees of freedom, encompassing changes in structure, motion, and color, and with tiny features in the micrometer range,” stated Dr. Sheila Russo, a co-author of the study, quoted Wyss Institute at Harvard.

To create Microfluidic Origami for Reconfigurable Pneumatic/Hydraulic or MORPH devices, the engineers first applied a technique called soft lithography. With the technique, they produced 12 layers of an elastic silicone that made the robot spider’s material basis. Next, they used a laser-micromachining technique on each layer to accurately cut out the mold. After that, they bonded appropriate molds to create the basic structure of the robot.

For producing the final product, the team applied the injection induced self-folding. The layers had been integrated with a pre-conceived network of hollowed microfluidic channels, as part of the main design. Using the third technique, they pressurized one set of the channels with a curable resin from the outside.

As a result, the individual layers and its neighboring layers bent into the final form when the resin settled. This enabled the swollen abdomen and downward-curved legs of the robot to become permanent characteristics.

According to Dr. Tommaso Ranzani, the first and corresponding author, they specifically controlled the folding process by adjusting the consistency and thickness of the silicone nearby the channels. They also cut the channels using a laser at various distances to create the final form.

The other microfluidic channels were utilized by the team for adding actuators to give the robot some color patterns and movements. Dr. Donald Ingber, founding director of Wyss Institute, said that MORPH devices may have the potential in biomedical applications, such as in microsurgery and endoscopy.