An actuator is the component in a machine or other mechanical device that enables movement. Actuators convert energy into mechanical forces to allow the machine to perform an action, much like certain muscles in the human body can convert energy into movement of the arms or legs.
Soft actuators are useful for a wide range of applications in which comfortable human interaction is important, such as environmental sensing, healthcare, wearable technologies, prosthetics and other medical devices, and haptic devices. Robots constructed with soft actuators are safer for human-robot interaction, making soft actuators attractive for manufacturing processes in the automotive world and in other industries.
Solving the manufacturing challenges that limit creation of soft actuators and flexible sensors
While soft actuators are inspired by biological systems, synthetic designs cannot replicate the complexity of the human body — but researchers are getting closer. The creation of soft actuators, however, presents an interesting challenge. The application of traditional manufacturing processes, such as casting and roll-to-roll processes, to the creation of soft actuators can be time-consuming and expensive, and limits the variable geometries that can be used in the production of these complex structures.
David Gonzalez Rodriguez, post-doctoral researcher with the School of Engineering Technology in Purdue University’s Polytechnic Institute, aims to address that challenge by studying the creation of 3D-printed flexible structures that can function as soft actuators.
“Additive manufacturing technology is growing so fast,” said Gonzalez Rodriguez. “But it still is a new technology, and we have a lot to study and innovate in this area.”
Gonzalez Rodriguez’s research, titled, “3D-printed soft actuators with embedded sensing and IoT capabilities,” studies the flexibility and effectiveness of 3D-printed materials to evaluate them as potential soft actuators and sensors. His two-part goal was first to characterize the properties of each flexible material and understand how it responds to external stimulus, and then to produce 3D-printed models that can be tested for effectiveness as soft actuators and sensors. Producing those models became a real hands-on process as Gonzalez Rodriguez had to modify 3D printers himself in order for the machines to work with the flexible materials he needed to study.
“Some companies are starting to produce 3D printers for flexible materials,” said Gonzalez Rodriguez, ”but right now those printers are designed for large industrial processes and are very expensive.”
So far, Gonzalez Rodriguez has successfully characterized the mechanical and electrical properties of 3D-printed flexible materials, including a close look at how specific 3D printing parameters — for example, the orientation of the printing angle and the number of layers printed — can affect the performance of the final product. As he explains, an important first step is “understanding the behavior of the material and how to use it properly for the desired application.”
Soft actuators and flexible sensors, unlimited possibilities
This novel approach, using additive manufacturing technologies to design and create soft actuators and flexible sensors, opens up a wide range of possibilities.
“Food production, manufacturing, construction, automotive, medical — I was curious and I came here to understand and learn everything about these technologies and how to bring it to the next level.”
Gonzalez Rodriquez points out that 3D printing soft actuators can be much less expensive than traditional manufacturing due to the reduction in wasted materials and the ability to precisely print the part needed. He sees a wealth of potential applications as this research continues; understanding the behavior of the 3D-printed materials is just the first step.
“It’s incredible how you can imagine and create something in your mind, then create it on your computer, and a few hours later you can hold it in your hand,” marveled Gonzalez Rodriguez. “This technology will be a cornerstone of the coming industrial revolution, and it will be in every industry.”