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Distributed Robotic Teams. Nikos Papanikolopoulos Professor, Department of Computer Science and Engineering Digital Technology Center University of Minnesota npapas@cs.umn.edu. AI, Robotics, and Computer Vision Laboratory, CSE, UMN . Faculty
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Distributed Robotic Teams Nikos Papanikolopoulos Professor, Department of Computer Science and Engineering Digital Technology Center University of Minnesota npapas@cs.umn.edu
AI, Robotics, and Computer Vision Laboratory, CSE, UMN • Faculty Maria Gini (Artificial Intelligence, Robotics, Intelligent Agents) Nikos Papanikolopoulos (Robotics, Computer Vision, Transportation Systems) Stergios Roumeliotis (Robotics, Robot Localization and Mapping) Rich Voyles (Robotics, Computer Vision, Multi- Agents) Paul Schrater (Computer Vision, Pattern Recognition, Haptic Interfaces)
AI, Robotics, and Computer Vision Laboratory, CSE, UMN • Mission Statement The goal of the laboratory is to combine algorithm development with strong system building efforts that validate our algorithms. With respect to teaching, the goal is to educate top researchers/teachers and use AI, robotics, and computer vision as the vehicle to promote science/engineering principles to our students.
Rangers and Scouts Heterogeneous robotic team Rangers General purpose off-road robots Scouts Custom portable sensor platforms
Technical Overview of the Project: Goals • Develop distributed robots (main unit is roughly the size of a soda can) with various mobility and sensory modes for exploration of structures in an urban warfare scenario. • Emphasize the development of innovative mobility modes for these robots. • Data fusion and analysis are to be at a remote operator station. • Effective combination of software and hardware design.
Some Applications • Special Unit Operations • Law Enforcement Agencies: • Hostage situations • Counter terrorist units in large cities • Fire and rescue • Disaster relief • Coast Guard: vessel boarding and search • FBI Fugitive Task Forces, FBI Crisis Response Team • NASA space exploration programs • Toy and Entertainment industries
Scout Designs Grasshopper Rolling Ball Scout 2001
Scout 2001 vs. Scout 1999 • Complete electronic and electrical redesign • Significantly improved power management • Encoders have been added to the drive motors. • The internal components have all been modularized to decrease assembly and repair time from hours to minutes. • The jumping spring and winching motor have been improved to increase overall mechanical efficiency and the height of jumps. Scout 2001 Scout 1999
Scout Jumping Trial (a) (b) (c) (d) (e) (f)
Hardware Efforts • Mobility improvements • Communication improvements Variable-size actuated scout wheels Rooftop scout with grappling hook COTSScout and MegaScout Scout repeaters
Variable-Size Actuated Scout Wheels wheel extended wheel retracted
Rooftop Scout • User feedback indicated the need for a scout that can operate on a roof or a ceiling. • The goal again is to achieve the desirable functionality without significant changes to the scout design. • The idea was to have an external scout attachment with a spring-loaded mechanism and a grappling hook. • Two prototypes have been built.
Rooftop Scout Grappling Hook Mechanism
Motion Detection and Tracking A computer vision algorithm was written to detect motion in the field of view and automatically track the center of motion.
Low Cost Alternatives • Commercial Off-The-Shelf (COTS) Scout • Designed to be a low cost, nearly disposable alternative with reduced functionality and slightly improved resilience • Physical Characteristics: 44 mm x 97 mm cylinder with 3 wheel sizes (57 mm, 64 mm, 76 mm) • Sensing Capability: Camera • Locomotion: • Rolling: Top speed • 57 mm wheel: 0.39 m/s • 64 mm wheel: 0.42 m/s • 76 mm wheel: 0.50 m/s • Operational Life: 190 minutes in quiescent mode, 60 minutes at top speed broadcasting video • Cost: < $300
Low Cost Alternatives • Commercial Off-The-Shelf (COTS) Scout
Modified Scout Platforms MegaScout
Control and Simulation • Control architecture is layered and based on behaviors. • Rangers are the control and communication central units (utility units). • Lego-based platforms were used initially for rapid prototyping and experimentation.
Prioritized Behaviors, Mission Decomposition, Parallel Execution Backbone Mission Control Scouts, Rangers, Radios, Video Frequencies, Framegrabbers, Launchers, etc. Resource Pool User Interface Supervisory Workstation Palm Pilot/Wristwatch TV’s Scheduling, System Configuration, Starting/Stopping Components, Load Balancing, etc. Software Implementation • CORBA • XML • C++
Behavior: Servo to a Target • Human selects target • Robot handles servoing process • Assumption: known target geometry • Deployment and retrieval of robot • Navigation between waypoints
Examples of Vision-Based Behaviors (Image Mosaics) The scout rotates 360 deg and blends the individual images in order to create mosaics of urban spaces.
General Innovations • Design and functionality of the scouts. • Design of the ranger-scout system (launching, communication, navigation). • Simple control and communication primitives that can be reconfigured for a variety of robot behaviors. • Development of a large heterogeneous distributed robotic system based on these scalable, reconfigurable behaviors and physical components. • Miniaturization of the scout hardware peripherals (e.g. sensing, communication, etc.) required significant innovation. • Creation of a large variety of mobility modes in order to increase the scout functionality.
Technical Challenges • Communication!!!!! • Power requirements and management* • Design of the jumping mechanism • Hardening* • Assembly and disassembly of the scout • Miniaturization* • Human-scout interaction given a large number of scouts • Software issues *High risk issues
Conclusions • The scout has proven to be a simple and effective design. It has been featured on CNN, BBC, NBC, Comedy Central, and was a finalist for the Discover award. • Feedback from military users (Lincolnia exercises) indicates that the scout is the right design and the right size. • There is a patent for the overall design. • Various innovative mobility enhancements have been developed. • The COTSScout has a long life and a satisfactory set of capabilities at a very low-cost. • A variety of user interfaces has been developed. • Communication remains a challenge.
Acknowledgements This material is based upon work supported by National Science Foundation through grant #EIA-0224363, Microsoft Inc., INEEL, and the Defense Advanced Research Projects Agency, MTO (“Distributed Robotics” Program), ARPA Order No. G155, Program Code No. 8H20, issued by DARPA/CMD under Contract #MDA972-98-C-0008
URL Information Videoclips and papers can be found at: http://distrob.cs.umn.edu Thank You