(Georgia Institute of Technology, 2012-12)
Williams, Stephen; Parker, Lonnie T.; Howard, Ayanna M.
The capability to monitor natural phenomena using mobile sensing is a benefit to the Earth science community given the potentially large impact that we, as humans, can have on naturally occurring processes. Observable phenomena that fall into this category of interest range from static to dynamic in both time and space (i.e. temperature, humidity, and elevation). Such phenomena can be readily monitored using networks of mobile sensor nodes that are tasked to regions of interest by scientists. In our work, we hone in on a very specific domain, elevation changes in glacial surfaces, to demonstrate a concept applicable to any spatially distributed phenomena. Our work leverages the sensing of a vision-based SLAM odometry system and the design of robotic surveying navigation rules to reconstruct scientific areas of interest, with the goal of monitoring elevation changes in glacial regions. We validate the output from our methodology and provide results that show the reconstructed terrain error complies with acceptable mapping standards found in the scientific community.
(Georgia Institute of Technology, 2010-12)
Williams, Stephen; Parker, Lonnie T.; Howard, Ayanna M.
Satellite-based instruments are now routinely used to map the surface of the globe or monitor weather conditions. However, these orbital measurements of ground-based quantities are heavily influenced by external factors, such as air moisture content or surface emissivity. Detailed atmospheric models are created to compensate for these factors, but the satellite system must still be tested over a wide variety of surface conditions to validate the instrumentation and correction model. Validation and correction are particularly important for arctic environments, as the unique surface properties of packed snow and ice are poorly modeled by any other terrain type. Currently, this process is human intensive, requiring the coordinated collection of surface measurements over a number of years. A decentralized, autonomous sensor network is proposed which allows the collection of ground-based environmental measurements at a location and resolution that is optimal for the specific on-orbit sensor under investigation. A prototype sensor network has been constructed and fielded on a glacier in Alaska, illustrating the ability of such systems to properly collect and log sensor measurements, even in harsh arctic environments.
(Georgia Institute of Technology, 2008)
Howard, Ayanna M.; Parker, Lonnie T.; Smith, Brian Stephen
This paper presents a methodology that utilizes soft computing approaches to enable locomotion of multiple legged robotic agents operating in natural terrain environments. For individual robotic control, the locomotion strategy consists of a hybrid FSM-GA approach that couples leg orientation states with a genetic algorithm to learn necessary leg movement sequences. To achieve multi-agent formations, locomotion behavior is driven by using a trained neural network to extract relevant distance metrics necessary to realize desired robotic formations while operating in the field. These distance metrics are then fed into local controllers for realizing linear and rotational velocity values for each robotic agent. Details of the methodology are discussed, and experimental results with a team of mobile robots are presented.