DTRA funds study of radiation-hardened robotics

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Assistant Professor Lei (Raymond) Cao, left, and Professor Yuan Zheng
The Defense Threat Reduction Agency (DTRA) in the Department of Defense (DOD) has awarded Lei (Raymond) Cao, assistant professor of nuclear engineering, and Yuan F. Zheng, professor of electrical and computer engineering, a $450,000 three-year grant to fund their collaborative research on radiation sensitivity of critical radiation-hardened robotic components.

The project team envisions an inter-disciplinary approach, combining expertise in nuclear science and engineering and robotics to study the radiation sensitivity and failure mechanism of a robot working in harsh radiation environments where human presence is prohibited.

In the March 2011 Fukushima nuclear plant accident in Japan, a robot named Monirobo (an environment monitoring robot) was deployed to the plant for surveying the damage. Unfortunately, Monirobo failed quickly under high levels of radiation. The challenge is that individual robotic components cannot sustain the radiation, which leads to the failure of the entire system. Radiation-hardened robotics is an area that has not been seriously addressed before. It constitutes a frontier topic due to the rapid growth of energy demands for which nuclear energy provides the base-load and no-carbon footprint electricity, as well as the governmental ability in dealing with the worst-case scenarios in case of accident.

While many research activities have been performed on radiation damage to electronic devices, such as sensors and encoders, there are only a handful of studies on other critical components of modern robotic systems. Topics of interest to current researchers include the failure mechanism of radiation-induced metal fatigue and embrittlement of the flexspline in a harmonic drive, and the radiation sensitivity of magnet in a DC motor.  

“There is a knowledge gap between robotic scientists and the radiation science,” says Cao. “This is an interdisciplinary area where our interests match.”

Cao’s research focuses on applying nuclear physics and radiation science to the interaction of different forms of ionizing radiation with materials, including the damage caused by radiation on material properties; the development of instrumentation and novel sensors to measure radiation; the use of neutrons and gamma rays as an interrogation tool to measure material properties; and the reactor physics.

“Mobile robots working in radiation-filled environments is a new and upcoming area in robotics,” says Zheng. “This new research project will provide Ohio State an opportunity to lead the field and to create a new knowledge base for radiation-hardened robotic components.”

Zheng is currently involved in the 2012 DARPA Grant Challenge for Robotics which launched in October. The purpose of the program is to enable a humanoid robot to operate in a damaged man-engineered environment, possibly a nuclear plant, autonomously. The current project will help develop such a robot in the future.

DTRA is the official Combat Support Agency for countering weapons of mass destruction (chemical, biological, radiological, nuclear, and high explosives). Cao has been named recipient of the 2011 DTRA Young Investigator Award for his work on neutron sensor for the replacement of He-3 detector. Each year DTRA presents only 10 to 15 awards nationally to researchers in the science and engineering fields. That award, together with the current project, are the first two DTAR grants won by Ohio State's College of Engineering faculty.