Fast moving microhooks

Left: Slow motion release using a heater trace, Right: real-time video of microhooks grasping a wire. The 200 micron (0.2 mm) diameter wire runs horizontally across the bottom of the right image.

To help our small sensors tap into power and send signals out, we have developed microhooks that grab onto wires. Grasping is triggered by an electric current that breaks polymer tethers at the ends of the hooks, allowing them to spring up into their preferred curly shape. Details are in our publication:

Seeking PhD students for FALL 2025

Robotics PhD Project

We have a Fall 2025 opportunity for a Ph.D. student at the University of Louisville in the area of fabric with embedded sensors and actuators for soft robotics. Students with Masters degrees in electrical engineering, mechanical engineering, textile engineering and natural sciences (physics/chemistry) are sought. This is an experimental project. It involves computer programming, modeling, and design work, but the main focus is hands-on lab work and data collection. This means the PhD student needs to be local during the entire degree program and carry out lab work in person. If you are interested and able to meet these requirements, go to our Join the Lab page for more details.

Morphing fabrics from elastic and wire

In this soft robotics project, a shape memory wire is stitched into stretched elastic fabric. The result: morphing structures that flatten when heated. We explore the design rules for these potato-chip shaped actuators and demonstrate them lifting and bending objects.

We have developed soft actuators called “Strained Elastic Membranes with Adjustable Modulus Edges” (SESAMEs). These fabric-based modules are made by stretching spandex fabric on a frame and installing shape memory wire borders using machine embroidery. When released from the frame, the SESAMEs take on a saddle shape that lets the wire bend a little and the fabric shrink a little. But when the shape memory wire is heated, it stiffens, increasing the cost of bending relative to fabric stretching and causing the saddle to flatten. The result is an actuator that cycles between 3D and flat shapes in soft robotics applications.

Paper:

Bringing the current

Previous REU student Nathan Song made his way to Boston this summer to present his work at the IEEE International Conference on Flexible, Printable Sensors and
Systems (FLEPS). Although the weather cancelled flights across the coast, Nathan made it. He presented a new way to connect up microdevices using flexible microgrippers to clip onto wires and deliver current. This method has the potential to bond many wires at once. The conference paper is here: