Nathan Farrington

Segway robotic mobility platform

The Segway Robotic Mobility Platform (RMP) is a new mobile robotic platform based on the self-balancing Segway Human Transporter (HT). The Segway RMP is faster, cheaper, and more agile than existing comparable platforms. It is also rugged, has a small footprint, a zero turning radius, and yet can carry a greater payload. The new geometry of the platform presents researchers with an opportunity to examine novel topics, including people-height sensing and actuation modalities. This paper describes the history and development of the platform, its characteristics, and a summary of current research projects involving the platform at various institutions across the United States.

Enhancing functionality and autonomy in man-portable robots

Current man-portable robotic systems are too heavy for troops to pack during extended missions in rugged terrain and typically require more user support than can be justified by their limited return in force multiplication or improved effectiveness. As a consequence, today’s systems appear organically attractive only in life-threatening scenarios, such as detection of chemical/biological/radiation hazards, mines, or improvised explosive devices. For the long term, significant improvements in both functionality (i.e., perform more useful tasks) and autonomy (i.e., with less human intervention) are required to increase the level of general acceptance and, hence, the number of units deployed by the user. In the near term, however, the focus must remain on robust and reliable solutions that reduce risk and save lives. This paper describes ongoing efforts to address these needs through a spiral development process that capitalizes on technology transfer to harvest applicable results of prior and ongoing activities throughout the technical community.

A Segway RMP-based robotic transport system

In the area of logistics, there currently is a capability gap between the one-ton Army robotic Multifunction Utility/Logistics and Equipment (MULE) vehicle and a soldier’s backpack. The Unmanned Systems Branch at Space and Naval Warfare Systems Center (SPAWAR Systems Center, or SSC), San Diego, with the assistance of a group of interns from nearby High Tech High School, has demonstrated enabling technologies for a solution that fills this gap. A small robotic transport system has been developed based on the Segway Robotic Mobility Platform (RMP). We have demonstrated teleoperated control of this robotic transport system, and conducted two demonstrations of autonomous behaviors. Both demonstrations involved a robotic transporter following a human leader. In the first demonstration, the transporter used a vision system running a continuously adaptive mean-shift filter to track and follow a human. In the second demonstration, the separation between leader and follower was significantly increased using Global Positioning System (GPS) information. The track of the human leader, with a GPS unit in his backpack, was sent wirelessly to the transporter, also equipped with a GPS unit. The robotic transporter traced the path of the human leader by following these GPS breadcrumbs. We have additionally demonstrated a robotic medical patient transport capability by using the Segway RMP to power a mock-up of the Life Support for Trauma and Transport (LSTAT) patient care platform, on a standard NATO litter carrier. This paper describes the development of our demonstration robotic transport system and the various experiments conducted.

Towards a Warfighter's Associate: Eliminating the Operator Control Unit

In addition to the challenges of equipping a mobile robot with the appropriate sensors, actuators, and processing electronics necessary to perform some useful function, there coexists the equally important challenge of effectively controlling the system’s desired actions. This need is particularly critical if the intent is to operate in conjunction with human forces in a military application, as any low-level distractions can seriously reduce a warfighter’s chances of survival in hostile environments. Historically there can be seen a definitive trend towards making the robot smarter in order to reduce the control burden on the operator, and while much progress has been made in laboratory prototypes, all equipment deployed in theatre to date has been strictly teleoperated. There exists a definite tradeoff between the value added by the robot, in terms of how it contributes to the performance of the mission, and the loss of effectiveness associated with the operator control unit. From a command-and-control perspective, the ultimate goal would be to eliminate the need for a separate robot controller altogether, since it represents an unwanted burden and potential liability from the operator’s perspective. This paper introduces the long-term concept of a supervised autonomous Warfighter’s Associate, which employs a natural-language interface for communication with (and oversight by) its human counterpart. More realistic near-term solutions to achieve intermediate success are then presented, along with actual results to date. The primary application discussed is military, but the concept also applies to law enforcement, space exploration, and search-and-rescue scenarios.

Transitioning unmanned ground vehicle research technologies

The Technology Transfer project employs a spiral development process to enhance the functionality and autonomy of mobile systems in the Joint Robotics Program (JRP) Robotic Systems Pool (RSP). The approach is to harvest prior and on-going developments that address the technology needs identified by emergent in-theatre requirements and users of the RSP. The component technologies are evaluated on a transition platform to identify the best features of the different approaches, which are then integrated and optimized to work in harmony in a complete solution. The result is an enabling mechanism that continuously capitalizes on state-of-the-art results from the research environment to create a standardized solution that can be easily transitioned to ongoing development programs. This paper focuses on particular research areas, specifically collision avoidance, simultaneous localization and mapping (SLAM), and target-following, and describes the results of their combined integration and optimization over the past 12 months.

Intelligent behaviors for a convoy of indoor mobile robots operating in unknown environments

Intelligent behaviors allow a convoy of small indoor robots to perform high-level mission tasking. These behaviors include various implementations of map building, localization, obstacle avoidance, object recognition, and navigation. Several behaviors have been developed by SSC San Diego, with integration of other behaviors developed by open-source projects and a technology transfer effort funded by DARPA. The test system, developed by SSC San Diego, consists of ROBART III (a prototype security robot), serving as the master platform, and a convoy of four ActivMedia Pioneer 2-DX robots. Each robot, including ROBART III, is equipped with a SICK LMS 200 laser rangefinder. Using integrated wireless network repeaters, the Pioneer 2-DX robots maintain an ad hoc communication link between the operator and ROBART III. The Pioneer 2-DX robots can also act as rear guards to detect intruders in areas that ROBART III has previously explored. These intelligent behaviors allow a single operator to command the entire convoy of robots during a mission in an unknown environment.