“In nature, complexity has a very low cost. Using new manufacturing techniques like 3D printing, we’re trying to translate this to robotics,” Tolley said.
The team’s research was financially supported by a grant from the Office of Naval Research and the UC San Diego Frontiers of Innovation Scholarship Program. Tolley, together with UC San Diego Jacobs School of Engineering PhD student Dylan Drotman, graduate student Saurabh Jadhav, former graduate student Phillip deZonia, and Mahmood Karimi, published a paper, titled “3D Printed Soft Actuators for a Legged Robot Capable of Navigating Unstructured Terrain.”
The abstract reads, “Soft robots have recently demonstrated impressive abilities to adapt to objects and their environment with limited sensing and actuation. However, mobile soft robots are typically fabricated using laborious molding processes that result in limited actuated degrees of freedom and hence limited locomotion capabilities. In this paper, we present a 3D printed robot with bellowed soft legs capable of rotation about two axes. This allows our robot to navigate rough terrain that previously posed a significant challenge to soft robots. We present models and FEM simulations for the soft leg modules and predict the robot locomotion capabilities. We use finite element analysis to simulate the actuation characteristics of these modules. We then compared the analytical and computational results to experimental results with a tethered prototype. The experimental soft robot is capable of lifting its legs 5.3 cm off the ground and is able to walk at speeds up to 20 mm/s (0.13 bl/s). This work represents a practical approach to the design and fabrication of functional mobile soft robots.”
The engineers closely predicted the robot’s real walking behavior ahead of time, which shows that other engineers designing soft robots will be able to make educated decisions about movement. Getting the UC San Diego robot up and moving is tied to the amount of pressure, the order of timing, and which pistons in the four legs are inflated when. The robot is tethered to an air pump and an open source board, but the researchers are currently working to miniaturize both of these so the robot will be capable of independent movement; Tolley said that the “challenge here is to find the right design for the board and the right components, such as power sources and batteries.”
While the robot can’t walk alone yet, the research team ran successful tests on the tethered quadruped: it was able to walk over sand, large rocks, and up inclined surfaces; it’s also able to transition from walking to crawling when entering a space that becomes increasingly more confined. The team will be presenting the robot at the upcoming IEEE International Conference on Robotics and Automation (ICRA) in Singapore. Discuss in the Soft Robot forum at 3DPB.com. [Source/Images: UC San Diego Jacobs School of Engineering]