Using the X-Box Kinect as a sensor to conduct centrifuge research
11 November 2016
A team of researchers have used the Kinect to replace sensors on its geotechnical centrifuge to understand how levees fail when overtopped by large floods.
To gaming enthusiasts, the Kinect is Microsoft’s motion sensor add-on for the Xbox 360 gaming console. The device provides a natural user interface that allows users to interact intuitively and without any intermediary device, such as a controller.
The interdisciplinary project, funded by the National Science Foundation (NSF), focused on soil erosion, levees, and flood protection systems.
To provide essential data for the rebuilding of the ravaged levees in New Orleans, for the past ten years engineers from the School of Engineering at Rensselaer have been studying small-scale sections of the flood-protection system.
According to the National Weather Service, flooding is a coast-to-coast threat to the United States and its territories nearly every day of the year. Flooding typically occurs when prolonged rain falls over several days, when intense rain falls over a short period of time, or when an ice and debris jam causes a river or stream to overflow onto a surrounding area. Flooding can also result from the failure of a water control structure, such as a levee or dam. Statistics from the National Weather Service note that from 1996 to 2015, approximately 1,640 Americans died in floods.
“To the best of our knowledge, this is the first time that a Kinect system has been used on a geotechnical centrifuge,” said Thomas Zimmie, a dam safety expert and professor of civil engineering. “The objective of this research is to develop tools that would improve the understanding of the process of levee failure because of erosion and reduce the future risk of failure in order to protect lives and property.”
During recent decades, there have been continuing efforts to study dam-break hydraulics, including numerical and experimental investigations of dam-break flows and the potential damage caused by the flows.
According to Zimmie, hydraulic erosion is a complicated phenomenon and depends on many different parameters. To improve design criteria for levees, embankments, and earthen structures, the development of realistic computer models that can simulate the erosion process is necessary.
As part of the research, a large number of physical levee erosion tests were performed using Rensselaer’s 150g geotechnical centrifuge. The centrifuge tests were performed to simulate real-size levees, in order to obtain a more realistic model. The erosion was modelled physically in detail.
Conventional three-dimensional scanning was used to precisely verify the calculated dimensions of initial and final computer model geometries, but did not yield interim data or measurements of the quantity of eroded soil during the tests.
The Kinect sensor was used to follow the progression of the soil erosion. The device was used to scan and evaluate the volume of eroded soil and variation of the shape of the channels as a function of time. Three-dimensional images were obtained, and variations of different parameters were plotted.
“Real-time field measurements are extremely difficult to obtain,” Zimmie said. “Numerical simulations play an ever-important role for dam-break flow problems. The erosion process is dependent on several parameters such as soil fines and clay size content, plasticity and dispersivity, compaction water content, density degree of saturation, clay mineralogy, and possibly the presence of cementing materials such as iron oxides.”
Based on recorded videos and pictures taken during the tests, it was discovered that the Kinect results agreed well with the physical models. The technical capabilities of the Kinect system can be duplicated in a custom design, but the cost could be several thousand dollars, Zimmie noted.
For the research team, the Kinect served as a low-cost sensor, enabling the measurement of the rate of soil erosion, which, if done at all, usually requires expensive equipment. The application of this method in other laboratory experiments was also investigated by the team.