CPS: Medium:Ant-Like Microrobots - Fast, Small, and Under Control

Abstract: 

No robots at the sub-cm3 scale exist because their development faces a number of open challenges. This project focuses on identifying and determining means for solving these challenges. In addition, it is providing new solutions to outstanding questions about resource-constrained algorithms, architectures, and actuators that can be widely leveraged in other applications. Our work has discovered new fundamental principles, design methods, and technologies for realizing distributed networks of sub-cm3, ant-sized mobile microrobots that self-organize into cooperative configurations. This project has produced a total of more than ten journal papers and twenty conference papers and a few papers are still in publication or in preparation. The scope of the project involves work in the areas: distributed algorithms and control, microfabricated mechanisms and actuation, and physical hardware for control. The research on algorithms and control has concluded the following research themes. In a search and surveillance scenario the goal is to find the minimum number of robots and an associated time-invariant memoryless control policy that guarantees that the largest number of states are persistently surveyed without visiting a forbidden state. We also worked on finding optimal control policies for robotic navigation under different constrains. For a linear time-invariant plant subject to sparsity constrains we designed a norm-optimal stabilizing controller. For microfabricated mechanisms and actuation we have worked on different actuators and their integration with micromechanisms in a way that can drive different types of locomotion and different gaits. The micro-scale actuators we studied include thermal actuators, dielectric elastomer actuators, and electroosmotic nastic actuators. Optimization of performance and characterizations of the mechanical properties were performed on these actuators. We have developed a number of hardware components that perform computational or driving functions necessary to control small robots, including components that contribute to very low frequency control of actuators, intended for applications of minimal robot implementations involving legged chips, components that generate analog random  numbers and compute sine functions to provide odometry estimation, high-voltage devices that generate and control the high voltages needed for many tiny-scale actuator technologies. Various robotic platform, BristleBot, “Wall-e”-Bot, and TinyTeRP, were developed with features like tiny-size, low-cost, and modular functionalities. The platforms can help experimentally test new distributed algorithms and controllers on minimal resource-based robots. Results from our work could be used for applications as diverse as search and rescue during disaster relief efforts, manufacturing, warehouse management, ecological monitoring, intelligence and surveillance, infrastructure and equipment monitoring, metrology, and medical applications such as cell manipulation and microfactories. This project has been providing a unique opportunity to train graduate and undergraduate students on the investigation of fundamental principles of CPS. More than twenty five graduate and undergraduate students have been supported by this project. Many other students were also involved in this project via the REU program and independent research. Our research team outreached to do demonstrations and share experience at several venues extending the number of   people who have learned important concepts from this work. These events include University of Maryland’s Robotic Day, 2013 National Robotics Week at the Air and Space Museum, Robotics Week at Koshland Science Museum, 2011 ISCAS in Rio de Janeiro Brazil, and University of Maryland’s 4-H Youth Program. The PIs were invited to give seminars, talks, and tutorials at many universities and conferences. The TinyTeRP is an open resource hardware and software platform,which is a resource contribution to research and education.