GritsLab

Current Projects

Specification-Based Maneuvering of Quadcopters Through Hoops

Motivated by creating systems that can achieve satisfying multiple objectives through user input, this paper approaches the use of quadcopters to manuever through suspended hoops. Often in scenarios like automated farming or surveillance, autonomous robots will need to satisfy a number of objectives over a finite amount of time with constraints on its state space. […]
Collisions as Information Sources in Robot Swarms

Collision avoidance is crucial for making multi-robot systems operate in a safe manner–to keep the robots safe, collisions should be avoided at all costs. In a number of robotic applications, collisions have the potential to be catastrophic, e.g., for fleets of unmanned aerial vehicles or platoons of self-driving trucks. However, as the density of robots […]
Closed-Loop Task Allocation Using Inter-Robot Encounters

Collaborative teams of robots can accomplish multiple tasks at the same time by dividing themselves among the tasks. For example, swarming robots operating in disaster-prone environments might be divided among different tasks such as surveillance, data relay, and rescue. The problem of allocating tasks to individual robots becomes especially challenging when there is no central coordinator […]
Voluntary Retreat for Interference Reduction

Collaboration is a great resource. As proven by biologists, physicists, and a number of social studies, groups of collaborating individuals can address complex tasks even under limited information and skills. Ants cooperate to create a sophisticated network of underground tunnels. Marine bacteria living at great depths build long chains in order to reach lower depths, more abundant […]
Coverage for Teams With Heterogeneous Sensing Capabilities

Coverage control concerns itself with the problem of distributing a collection of mobile sensor nodes across a domain in such a way that relevant environmental features and events are detected by at least one sensor node (with sufficiently high probability). How a team is covering the domain is typically asked relative to an underlying density function, […]
Performance Regulation and Tracking via Lookahead Simulation: Preliminary Results and Validation

Paper Submitted to CDC 2017. Download the video.
Safe Open-Loop Motion Strategies for Handling Communication Failures in Multi-Robot Systems

This project aims to formulate a motion strategy that allows robots to safely handle critical communication failures in multi-robot systems where a central decision maker is specifying the movement of each individual robot. For each robot, the proposed algorithm computes a time horizon over which collisions with other robots are guaranteed not to occur. These safe time horizons are included in the commands being […]
Precision Agriculture

Agricultural automation presents challenges typically encountered in the realm of cyber-physical systems, such as incomplete information (plant health indicators), external disturbances (weather), limited control authority (fertilizers cannot make a plant mature arbitrarily fast), and a combination of discrete events and continuous plant dynamics. In this project, we focus on the particular problem of optimal pesticide spray […]
Game-theoretic Self-reconfiguration

This project aims to formulate the homogeneous two- and three-dimensional self-reconfiguration problem over discrete grids as a constrained potential game. We develop a game-theoretic learning algorithm based on the Metropolis-Hastings algorithm that solves the self-reconfiguration problem in a globally optimal fashion. Both a centralized and a fully decentralized algorithm are presented and we show that […]
Musical Abstractions for Multi-Robot Control

How one single operator should influence the performance of a large group of robots is not a simple question in that it depends on various factors, including the size and composition of the team as well as the objective task to be performed. This work introduces music theory as a new approach for multi-robot control […]
Trust in Human-Robot Teams

Trust- based coordination occurs when a team of robots and possibly humans have to work together to achieve some goal, but each robot (and/or human) may not trust all of the other robots (and/or humans). If a robot doesn’t trust one of its neighbors, it may not want to heavily weight the information obtained from […]
Robotarium

Multi-robotic testbeds are an integral part of multi-agent research, yet they are expensive to develop and operate. This in turn makes them unaffordable for most but a select few researchers at well-endowed universities, slows the rate of progress of multi-agent research, and limits the number of educational multi-robot tools available to students. The goal of […]
Safe Swarm Robotics

When designing coordinated controllers for teams of mobile robots, the primary control objective tends to drive the behavior of the team so as to realize tasks such as achieving and maintaining formations, covering areas, or collective transport. Safety, in terms of collision avoidance is added as a secondary controller to override the controller when collision […]
The GRITSBot

The goal of the GRITSBot project is to make multi-agent experiments more accessible to the research community at large as well as to students of all age groups (highschool, undergraduate education, as well as graduate education). In a further step, we intend to open up a show testbed to the general public. Revision 1 of […]
Robust Multi-Agent Networks

The objective of this research is to develop decentralized methods for achieving robustness in multi-agent networks through self-organization. Multi-agent networks typically consist of numerous components that interact with each other to achieve some collaborative tasks. In many applications, the network may face functional or structural challenges such as failures, noise, or malicious attacks, to name a few. Under such perturbations, a desirable […]
Robotic Mixing Using Braids

We approach the problem of having robots mix, or interact with each other consistently in the same space, by borrowing concepts from algebraic topology, namely from the Braid Group.
Sim.I.am

Sim.I.am is a mobile robot simulator designed to allow students to bridge the gap between theory and practice in control theory. It enables students to design controllers for a mobile robot, test these controllers in a simulator, and then deploy these controllers on an actual robotic platform: the Khepera III mobile robot (and others). This […]
Coordination Using Set-valued Sensors

What is the minimum amount of information required by a team of networked agents to solve a geometric task? This notion of minimality is explored through the use of set-valued sensors, and the question then becomes what assumptions need to be made on these sensor models. In fact, the set-valued sensor provides a general model […]
Control of Multi-Agent Systems Using Time-Varying Density Functions

In this project, optimal coverage ideas are used to control a multi-agent system. In optimal coverage, we are concerned with finding the algorithm that will drive the agents to position themselves in ‘best’ locations, when given a certain density function that represents spatial ‘importance’. For example, this density function may be a probability density function of […]
Power-aware Sensor Networks

As the trends towards decentralization, miniaturization, and longevity of deployment continue in many domains, power management has become increasingly important. In sensing and communications networks, power management has long been a part of the design paradigm. However, an underlying assumption in most of the existing work is that the performance of the sensing devices remain […]
Heterogeneous Self-Reconfiguration

This project develops a novel approach for heterogeneous self-reconfiguration of a modular robot comprised of heterogeneous cubic modules. We allow an arbitrary number of modules and module classes and show that the proposed self-reconfiguration algorithm can guarantee completion of heterogeneous self-reconfiguration sequences by avoiding so-called hole obstructions. We introduce a hole-detection algorithm to avoid creating […]
Mapping Global Network Computations to Local Rules

In networked systems, a designer often has a higher level goal in mind which he wants to achieve with local rules. Examples of possible goals are rendezvous and formation control. This project aims to find general methods by which arbitrary global behaviors can be mapped on to local network interactions. Initial work has shown that […]
Haptic Interactions with Multi-Robot Swarms Using Manipulability

In the case of leader-follower networks, one or more agents (the leaders) can be used to inject control inputs into the system. In these networks, one can analyze the “effectiveness” of the inputs by borrowing a notion from robotics known as manipulability. In robotics, manipulability indices were developed as a means to analyze the […]
NextGen Air Transportation Systems

Several Next Generation Air Transportation Systems concepts require aircraft to be able to safely fly routes on the same airspace in a timely fashion. Therefore it is necessary that aircraft are able to navigate on routes with spatial and temporal constraints. Here at the GRITS Lab, we propose an optimal control approach at solving the problem.
Proportional-Integral Distributed Optimization

Many tasks to be solved by multi-agent systems can be formed in terms of a cost, where task completion corresponds to minimizing the cost. For example, the figure below depicts multi-agent formation control where agents must collectively decide upon parameters of the formation (such as displacement, rotation, and spread) while moving into position. By having […]
Learning to Locomote

As robots evolve they are becoming increasingly “smarter”, but still can not and do not learn the way humans learn. For example, humans have evolved to move by walking or running; however, humans can learn how to move by other means (e.g. swimming, skateboarding, riding bikes, etc.). I don’t know of any current robot that […]
Spatio-Temporal Routing

The idea behind this project is to route multiple robots to service spatially distributed requests at specified time instants, while optimizing some criterion, for instance the total distance travelled, or the total time of travel. The routing problem is similar to the well known Multiple Traveling Salesman Problem (m-TSP) or the Vehicle Routing Problem (VRP), except […]
Self-reconfiguring Robots

The goal of this project is to develop distributed control strategies to automatically reconfigure an ensemble of individual robotic modules from an initial configuration into a desired target configuration. A configuration in our work is a three-dimensional geometric arrangement of cubic modules where a cubic module is the basic building block of our system. Modular […]
Autonomous Marionettes

The project is divided into three main research tasks: Puppet Choreography with Motion Programs, Imitating Human Motions, and Distributed Protocols for Coordinating Puppets.
Assignment and Formation Control

The primary goal for this research is to develop a method of dynamic role assignment and formation control for multi-robot systems for rotationally and translationally invariant formations. Most previous work has treated assignment and formation synthesis as two separate problems.
Adaptive Time Horizon for MPC

The typical approach in the receding horizon framework is to choose a fixed time horizon over which to predict the unknown variables and obtain the optimal control input. If we had perfect estimates we could then make the time horizon as large as possible subject to factors such as computation speed, convergence, stability, and satisfaction […]
Dancing Robots

Stylistic Task Specification Framework applied to Aldebaran NAO robotic platform Typically, robotic algorithms focus on tasks which have concrete, functional objectives. Our framework aims to allow for more general specification based on stylistic considerations. Namely, we may think of the movement styles exhibited by classical ballerinas, disco dancers, and cheerleaders as differentiated by distinct stylistic tasks. […]
Mobile Communication Networks

Mobile Communication Networks Exploration of complex and dangerous territories posts great challenges for robotics research. Intuition suggests that using cooperative multiple vehicles will increase time efficiency. Coordination of multiple vehicles typically relies on communication between vehicles, but direct communication is easily blocked or at least attenuated by obstacles. Hence one major challenge for a successful […]
Bio-Inspired Systems

Biologically Inspired Heterogeneous Networks Social behavior of animals can offer solution models for missions involving a large number of heterogeneous vehicles, such as light combat ships, unmanned aerial vehicles, and unmanned underwater vehicles. We draw inspiration from the bottlenose dolphins, Tursiops truncatus, and develop coordination algorithms for heterogeneous multi-agent systems that are expressive enough to […]
Hybrid Systems

Optimal Control of Hybrid Systems Hybrid systems can accurately model a large number of systems in many application domains where traditional non-linear systems can not. Since they are generally not as well understood, the options to control hybrid systems are usually more limited. Recently, there has been an enormous interest to use optimal control for […]
Heterogeneous Cooperative Networks

Network topology based characterization of heterogeneity Heterogeneity has emerged as an important aspect of multiagent systems, in which agents with different capabilities and resources interact with each other to perform various complex tasks. In this work, we aim to provide a framework for a network topology based characterization of heterogeneity in multiagent and cooperative networks that also incorporates […]
Networked Robotics

Automatic Deployment of Mobile Robots This is part of a National Aeronautics and Space Administration (NASA) project. The premise is to use a mobile sensor network of mobile robots to study the effects of climate change on Antarctica. Our aim is to provide high-level control for the mobile sensor network. To this end, we are […]
Group-based Leader Follower Control

The basis of this work is creating application specific leader follower network topologies that are completely controllable. In particular, single leader networks are considered where the input signal is injected at the leader node and the follower nodes execute a nearest neighbor averaging rule. Under this set up, each network topology can be partitioned into […]
Merging and Spacing

Distributed Air Traffic Scheduling During Terminal Approach Conventional air traffic management (ATM) practices are known to be too rigid to accomodate for the projected increase in air traffic over the next few decades. To address this issue, the FAA’s NextGen iniative aims to introduce a set of technologies that will modernize the national […]
Convoy Protection

Scalable UAV Ground Convoy Protection When in a hostile environment, obtaining reliable information about upcoming threats ahead of time could mean the difference between life and death. Unmanned aerial vehicles (UAVs), which can travel at high velocities and have a large field of vision, are excellent tools for performing such reconaissance missions. Here […]