Because of their high precision and speed, Delta robots are deployed in many industrial processes, including pick-and-place assemblies, machining, welding, and food packaging. Starting with the first version Reymond Clavel developed for a chocolate factory to quickly place chocolate pralines in their packages, Delta robots use three individually controlled and lightweight arms that guide a platform to move fast and accurately in three directions. The platform is either used as a stage, similar to the ones used in flight simulators, or coupled to a manipulating device that can, for example, grasp, move, and release objects in prescribed patterns. Over time, roboticists have designed smaller and smaller Delta robots for tasks in limited workspaces, yet shrinking them further to the millimeter scale with conventional manufacturing techniques and components has proven fruitless.
Reported in Science Robotics, a new design, the milliDelta robot, developed by Robert Wood’s team at Harvard’s Wyss Institute for Biologically Inspired Engineering and John A. Paulson School of Engineering and Applied Sciences (SEAS), overcomes this miniaturization challenge. By integrating their microfabrication technique with high-performance composite materials that can incorporate flexural joints and bending actuators, the milliDelta can operate with high speed, force, and micrometer precision, which together make it compatible with a range of micromanipulation tasks in manufacturing and medicine.
In 2011, inspired by pop-up books and origami, Wood’s team developed a micro-fabrication approach that enabled the assembly of robots from flat sheets of composite materials. Pop-up MEMS (short for microelectromechanical systems) manufacturing has been used since then to build dynamic centimeter-scale machines that can simply walk away, or, as in the case of the RoboBee, fly. In their new study, the researchers applied their approach to develop a Delta robot measuring a mere 15-by-15-by 20 mm.
“The physics of scaling told us that bringing down the size of Delta robots would increase their speed and acceleration, and pop-up MEMS manufacturing, with its ability to use any material or combination of materials, seemed an ideal way to attack this problem,” said Wood, who is a core faculty member at the Wyss Institute and co-leader of its Bioinspired Robotics platform, and the Charles River Professor of Engineering and Applied Sciences at SEAS. “This approach also allowed us to rapidly go through a number of iterations that led us to the final milliDelta.”