Anthony Cowley

Maintaining network connectivity and performance in robot teams

In this paper, we present an experimental study of strategies for maintaining end-to-end communication links for tasks such as surveillance, reconnaissance, and target search and identification, where team connectivity is required for situational awareness. Our main contributions are threefold: (a) We present the construction of a radio signal strength map that can be used to plan multi-robot tasks, and also serve as useful perceptual information. We show how a nominal model of an urban environment obtained by aerial surveillance, is used to generate strategies for exploration. (b) We present reactive controllers for communication link maintenance; and (c) we consider the differences between monitoring signal strength versus data throughput. Experimental results, obtained using our multi-robot testbed in three representative urban environments are presented with each of our main contributions.

Adaptive Teams of Autonomous Aerial and Ground Robots for Situational Awareness

This is a preprint of an article accepted for publication in the Journal of Field Robotics, copyright 2007. Journal of Field Robotics 24(11), 991–1014 (2007)

Automated biomanipulation of single cells using magnetic microrobots

Transport of individual cells or chemical payloads on a subcellular scale is an enabling tool for the study of cellular communication, cell migration, and other localized phenomena. We present a magnetically actuated robotic system capable of fully automated manipulation of cells and microbeads. Our strategy uses autofluorescent robotic transporters and fluorescently labeled microbeads to aid tracking and control in optically obstructed environments. We demonstrate automated delivery of microbeads infused with chemicals to specified positions on neurons. This system is compatible with standard upright and inverted light microscopes and is capable of applying forces less than 1 pN for precision positioning tasks.

Deploying Air-Ground Multi-Robot Teams in Urban Environments

We present some of the work performed in the GRASP Laboratory with the objective of deploying multi-robot teams in urban environments. Specifically, we focus on three important issues in this type of mission: the development of tools for providing situational awareness, the use of air and ground vehicles for cooperative sensing and the construction of radio maps to keep team connectivity. We describe the main approaches that we have been using for tackling these issues and present some preliminary results from experiments conducted with our team of air and ground vehicles.

Towards the deployment of a mobile robot network with end-to-end performance guarantees

Communication is essential for coordination in most cooperative control and sensing paradigms. In this paper, we present an experimental study of strategies for maintaining end-to-end communication links for tasks such as surveillance and search and rescue where team connectivity is essential for providing situational awareness to a base station. We consider the differences between monitoring point-to-point signal strength versus data throughput and present experimental results with our multi-robot testbed in outdoor environments

Parsing Indoor Scenes Using RGB-D Imagery.

This paper presents an approach to parsing the Manhattan structure of an indoor scene from a single RGBD frame. The problem of recovering the floor plan is recast as an optimal labeling problem which can be solved efficiently using Dynamic Programming.

ROCI: a distributed framework for multi-robot perception and control

This paper presents ROCI, a framework for developing applications for multi-robot teams. In ROCI, each robot is considered a node, which contains several modules and may export different types of services and capabilities to other nodes. Each node runs a kernel that mediates the interactions of the robots in a team. This kernel keeps an updated database of all nodes and the functionalities that they export. Multi-robot applications can be built dynamically by connecting modules that may be running on different nodes over the network. As an example, we present an obstacle avoidance task implemented using our framework and also discuss the use of ROCI in a multi-robot scenario.

Wireless manipulation of single cells using magnetic microtransporters

For such biomedical applications as single cell manipulation and targeted delivery of chemicals, it is important to fabricate microstructures that can be powered and controlled without a tether in fluidic environments. In this work, we describe the construction and operation of micronsized, biocompatible ferromagnetic microtransporters driven by external magnetic fields capable of exerting forces at the pico Newton scale. We develop microtransporters using a simple, single step micro fabrication technique that allows us to produce large numbers in the same step. We also fabricate microgels to deliver drugs. We demonstrate that the microtransporters can be navigated to separate individual targeted cells with micron-scale precision, and deliver microgels without disturbing the cells in the neighborhood and the local microenvironment.

Fast scene analysis using image and range data

This paper presents a scheme which takes as input a 3D point cloud and an associated color image and parses the scene into a collection of salient planar surfaces. The scheme makes use of a fast color segmentation scheme to divide the color image into coherent regions and the groupings suggested by this procedure are used to inform and accelerate a RANSAC based interpretation process. Results on real data sets are presented.

Distributed sensor databases for multi-robot teams

We describe our implementation of a distributed sensor database that was designed to support the activities of teams of mobile robots as they explore an environment. Importantly, this approach effectively separates the process of acquiring sensor data from that of exploiting it. This allows us to develop applications where robots and human users can automatically discover and utilize sensor measurements acquired by other robots in the team. We also explain our approach to implementing distributed queries, an important capability that allows us to perform queries in a way that makes best use of the limited available communication bandwidth. Finally, we briefly describe how we have used this system to support situational awareness tasks.