The Robotics Institute

My research interests center on mobile robots in unpredictable environments, such as natural terrain and outdoor worksites, including computer architectures to control mobile robots, modeling and planning for non-repetitive tasks, complex problems of objective sensing in random or dynamic environments, and integrations of complete field robot systems.

My record includes the unmanned, teleoperated worksystems that performed cleanup at the damaged Three Mile Island nuclear facility; autonomous robots the Terregator, Locomotion Emulator, FastNav, Ambler, and others. My current activities include walkers for planetary exploration, navigators for underground and surface mining, excavators, waste site investigators, and reactor service robots.

My work encompasses core research, prototyping, and experimentation with the view that all are important to the evolution of field robots. Increasingly, my research interests are manifested through the work of the Field Robotics Center (FRC), which I direct. I have particular agenda in integrating component technologies into complete systems that prove themselves in both research and real world contexts. At FRC we developed the remote work systems that explored and remediated the basement of the crippled Three Mile Island reactor containment basement. The Remote Reconnaissance Vehicle performed recovery tasks such as inspection, radiological mapping, material sampling, sludge transport and wall cleaning in a highly radioactive environment. Its successor, the Remote Work Vehicle (RWV), a telerobot of unprecedented capability and nuclear qualification, was developed for a broad agenda of clean-up operations. The RWV can wash contaminated surfaces, remove sediments, demolish radiation sources, apply surface treatments, and package and transport materials.

FRC demonstrated early robot intelligent behavior in the Robotic EXcavator (REX) project, pioneering the task of autonomous digging through a complete synthesis of sensing, planning, and motion control for unmanned, benign excavation. Our autonomous outdoor navigation research dates from Terregator, the earliest of our locomotors and a testbed for some of the first research in computer vision for mobile robot guidance. The NavLab project, a current effort, aspires to develop stereo and laser imaging, sensor fusion, and autonomous path planning and navigation. An automated van, which accommodates researchers and all computing onboard, serves as the testbed for NavLab research.

The FastNav project investigated the areas of path tracking and collision avoidance for robot vehicles in featureless terrains, such as strip mines and hazardous waste sites. Collision avoidance was accomplished by searching a section of the path ahead of the vehicle using laser ranging. To guarantee collision avoidance, it is necessary to guarantee detection by the sensor and real time response from the computing and vehicle actuators. Path tracking was accomplished by servoing to a specified path using sophisticated inertial guidance. To date we have successfully demonstrated path tracking on the NavLab at 25 km per hour using a kinematic model of the vehicle. In the future we plan to extend our control schemes to track paths at higher speeds by incorporating vehicle dynamics and to detect obstacles on undulating terrain.

From sensor research in subsurface investigation, we developed the Portable Pipe Mapper (PPM), a hand-held pipe mapping system that collects, enhances, and displays a gray-scale map of buried ferrous pipes. The PPM gives the user a powerful tool for inferring utility line location through a visual and spatial representation of sensor data. It displays elbows, Ts, and crosses in piping networks and provides an accurate depth estimation of a target pipe.

We are developing a Site Investigation Robot to increase the efficiency of hazardous waste site investigations by integrating automated data acquisition, advanced subsurface sensing, robotic positioning, and site data basing through a uniform user-friendly interface. We have automated ground penetrating radar (GPR) scanning and data acquisition, using robotic technology to provide high accuracy for signal processing. Our work in three-dimensional image processing matches the three dimensional potential of GPR, achieving higher resolutions and full-volume imaging. Ultimately, a field technician will be able to scan a site and determine the type and locations of objects for excavation.

Our research into the automation of subsurface mining machines, specifically in the area of navigation, motion safe-guarding and position registration, has demonstrated corridor following using our Terregator equipped with sonar and laser range sensors. Current research is supported by the Locomotion Emulator (LE), an omnidirectional locomotion testbed. The LE's distinction as a testbed lies in its ability to emulate a wide variety of target vehicles, of which mining machines are examples, through software reconfiguration. The success of the LE is measured in part by the extent to which software for a target application, developed on the LE, ports to end use with minimum modification.

We are developing the Ambler, a six-legged walking robot that addresses the challenges of exploring rugged terrains, acquiring samples, and avoiding dangerous situations. The Amber's legged configuration overcomes three significant liabilities of precedent walkers: complexity of coordination control, resultant energy losses, and redundancy for continued function after loss of some motions. The Amber's actuator groups are orthogonal; the Ambler can thus level without propelling, can propel without leveling, and exhibits no power coupling between the two. This configuration enables a tractable control model and eliminates the energy loss of actuator conflict. In addition, the Ambler enables energy-efficient overlapping gaits unprecedented by animals and other robot walkers. The Ambler incorporates true functional redundancy it can lose up to two legs and still walk. Other critical issues in the project include perception and locomotion of rugged terrain, self-assessment, safeguarding, gait planning, control, and ultimate self-reliance.