Cultivating sustainable systems: Stavros Vougioukas embraces ag tech challenges

The CITRIS principal investigator and biological and agricultural engineering professor harnesses robotic and automated technology to optimize designs, systems and processes in agriculture and beyond.

"Engineers are problem-solvers. We're moved by challenges — how do you accomplish something that's not easy to do?" said Stavros Vougioukas, a professor of biological and agricultural engineering at the University of California, Davis, and a principal investigator (PI) at the Center for Information Technology Research in the Interest of Society and the Banatao Institute (CITRIS). 

"What motivates me is building technology that can help us grow more food in a more sustainable fashion, while also making technology that works alongside people to help them."

Vougioukas joined the Department of Biological and Agricultural Engineering at UC Davis in 2012, and he currently serves as the department's vice chair and undergraduate adviser. His work explores agricultural robotics and mechanization, or the process of introducing machines to perform labor previously done by humans or animals. 

He is also a researcher with the Artificial Intelligence Institute for Next Generation Food Systems (AIFS), a cross-country collaboration funded by the National Science Foundation and U.S. Department of Agriculture (USDA) to integrate artificial intelligence (AI) with food production.

He has been a senior member of IEEE, the world's largest organization for technology professionals, since 2019, and has published more than 140 journal and conference papers to date.

Originally from Greece, Vougioukas received his undergraduate degree in electrical engineering from Aristotle University of Thessaloniki. With the support of a Fulbright fellowship, he received a master's degree in electrical and computer engineering from the State University of New York at Buffalo and a doctorate in robotics and automation from Rensselaer Polytechnic Institute.

"I started working in agricultural robotics by accident, if you will, since I am an electrical engineer by trade," he said.

"But instead of just developing software models and simulations, I really wanted to build things, to get my hands and feet dirty at the orchards. When the opportunity came up at UC Davis, I moved over, and I'm really happy about that."

Vougioukas learned of CITRIS and the Banatao Institute when CITRIS leadership visited UC Davis's campus in search of faculty affiliates for the nascent CITRIS People and Robots (CPAR) initiative. Soon after the start of CPAR, Vougioukas, UC Merced's Stefano Carpin and UC Berkeley's Ken Goldberg began collaborating on the Robot-Assisted Precision Irrigation Delivery (RAPID) project.

RAPID, which received nearly $1 million from the USDA in 2016, sought to optimize drip irrigation in the vineyards of the Central and Napa valleys by individualizing the amount of water received by each plant. The team's system used handheld devices operated by field workers paired with robotic emitters attached to irrigation lines to precisely deliver the exact amount of water each vine needed for peak health and yield.

Also in 2016, Vougioukas was awarded CITRIS Seed Funding alongside fellow UC Davis biological and agricultural engineering professor David Slaughter, as well as other UC Davis and UC Berkeley colleagues, to develop robots to assist in plant phenotyping research in the field. 

Plant breeders aim to optimize crop traits, such as growth rate and time of flowering, to resist drought and disease and to produce higher yields. The autonomous robotic system that the team designed, fabricated and field-tested took phenotyping data — measurements of physical characteristics such as height and number of leaves — beneath the canopies of sorghum and other biofuel crops with less damage than a human worker might impart in taking similar appraisals.

By gathering data on physical traits more efficiently, the machine will help biologists draw a fuller picture of the relationship between a plant's phenotype and its genotype, the inheritable genetic code that influences its growth. Ultimately, that information could aid attempts to breed more resilient food sources and more effective energy crops. 

Vougioukas also received a 2021 CITRIS Seed Award to work with UC Merced mechanical engineers Ricardo Pinto de Castro and Reza Ehsani, to create a tool that helps farm managers decide when to deploy the electric and diesel tractors in their fleets to balance their technical performance needs with economic and energy costs.

For his 2022 CITRIS Seed Award project, Vougioukas teamed up with UC Berkeley civil and environmental engineer Dimitrios Zekkos to take his robotics expertise out of the orchard and into a … perhaps unexpected venue. 

Zekkos, whose research interests include infrastructure resilience, wanted to bring remote sensing, robotics and intelligent systems into the modern landfill. After encountering Vougioukas in a series of virtual meetings (and noting their mutual Greek heritage!), he approached Vougioukas to see if he was open to collaborating on a project to use uncrewed aerial vehicles, also known as UAVs or drones, and autonomous ground robots to measure, map and monitor methane emissions in landfills. 

Methane is a powerful greenhouse gas and a notorious landfill byproduct.

"From the moment I reached out to him, he was very supportive and responsive," Zekkos said. "He has been ready to listen and understand the problem, since landfills are not something that he likely even thought about before this.  He is certainly willing to apply his expertise to broader areas."

Zekkos, Vougioukas and team have been working with a local Northern California landfill to deploy ground robots and drones to gather preliminary data. Vougioukas's current objective is to find optimal paths for the robots to use to traverse the landfill.

"We have to program the electric-powered robots so they are able to drive and fly over the terrain without damaging themselves, while also respecting their energy constraints," he said.

The project aims to offer more accurate measurements of methane levels to help verify the extent to which landfills are contributing to climate change. The team also sees this endeavor as the first step in enabling landfill operators to detect methane leaks quickly — and then capture the gas so it can be used as a sustainable energy source.

Beyond his diverse slate of CITRIS-supported work, Vougioukas's research group at UC Davis continues to develop techniques and technologies to improve the efficiency and working conditions of human laborers through automation and mechanization. 

One such device met a critical need for the campus community during a recent public health crisis. At the beginning of the COVID-19 pandemic, Vougioukas, UC Davis development engineer Dennis Sadowski and postdoctoral researcher Zhenghao Fei invented rotator-mixer machines to help treat saliva samples at the UC Davis Genome Center for their award-winning asymptomatic testing program. Lab workers were straining their arms manually shaking test tubes, and the new machines were able to standardize the process and manage an impressive number of samples consistently — and painlessly.

In the agricultural engineering realm, Vougioukas's focus is on increasing crop yield and easing the harvesting process.

In 2021, Vougioukas received $1.6 million from the National Science Foundation and the National Institute of Food and Agriculture to develop two fruit-picking machines: one equipped with cameras and neural networks to identify fruits that are ripe and ready to be harvested, and another to supplant standard shake-and-catch systems with a system gentle enough to gather soft tree-grown produce, such as apples and peaches, without damaging them.

A long-term project that has recently borne fruit for Vougioukas is the creation of fragile crop harvest-aiding mobile robots, or FRAIL-bots, which work alongside human pickers to transport containers filled with easily bruised crops, such as strawberries, to unloading stations. According to the team's initial studies, FRAIL-bots can save up to 25 percent of harvesting time, which could lead to greater pay for field workers and reduced cost and production risk for growers. 

Vougioukas and members of his lab recently co-founded a startup to commercialize this technology with assistance from UC Davis Venture Catalyst.

In addition to his extensive research efforts, Vougioukas also works to hone his considerable instructional capabilities. He's an avid proponent of active collaborative learning in courses, which places students in peer groups to solve problems, address gaps and misconceptions in knowledge, and develop the team-based skills that will serve them well as working engineers. The UC Davis College of Engineering recognized him with an Excellence in Teaching Award in 2022 for his contributions. 

CITRIS leadership are in accordance with Vougioukas's many recent accolades. 

"It has been great to see Stavros's growing collaboration with CITRIS over the years," said Director Costas Spanos, the Andrew S. Grove Distinguished Professor of Electrical Engineering and Computer Sciences at UC Berkeley. "His dedication in using robotics in these critical areas is quite timely and a big boost to our mission to make the world better through innovating information technologies."