A team of engineering students at Fresno State is developing a robotic system designed to harvest citrus fruit. The project has reached field testing, where the robotic hand has met key technical requirements, including cutting stems to the required length without leaving sharp edges.
"The stem has to be as short as possible so as not to damage the other fruit in the bin, but it also has to be intact so the fruit remains protected," said Alaeddin Milhim, assistant professor in the Department of Mechanical Engineering.
The project began in February 2024 and involves a group of students working on different components of the system. The robotic platform uses a camera to capture images of trees, identify fruit, and assess ripeness. A dataset of more than 2,000 images is used to support selection. Once fruit is identified, the system directs a robotic arm to cut and transfer it to a bin.
Juan Espinoza Jr., a graduate student involved in the project, said the system addresses labor-intensive harvesting practices. Citrus harvesting involves carrying sacks that can weigh up to 40.8 kilograms and using ladders to access fruit. "It is a demanding task that can also be dangerous," he said.
He noted that labor availability is decreasing due to multiple factors, including enforcement and workforce changes. "I think something needs to be done to look at the long-term solution for labor issues," Espinoza said.
The system is still under development and is estimated to be at least two years away from commercial use. Planned improvements include increasing picking speed, adding multiple robotic arms, and developing autonomous operation. "It could have maybe five, six, or maybe even eight arms, all working at once, harvesting fruit," Milhim said.
The project has received more than US$100,000 in funding from the F3 Coalition, a US$65 million initiative focused on climate-related agricultural technologies. Citrus industry representatives have also observed field trials, including staff from a major U.S. citrus grower.
The system is being developed to address harvesting efficiency and labor constraints, with further testing and technical development ongoing.
Source: The Fresno Bee
