A development by agricultural engineers at Pennsylvania State University might be of interest to Armagh readers.
The Penn State boffins have developed, for the first time, a prototype “end-effector” capable of deftly removing unwanted apples from trees – the first step toward robotic, green-fruit thinning.
The development is important, according to Long He, assistant professor of agricultural and biological engineering, because manual thinning is a labour-intensive task, and the shrinking labour force in apple production makes manual thinning econ-omically infeasible.
His research group in the College of Agricultural Sciences conducted a new study that led to the end-effector.
Prior to designing the end-effector, researchers performed a series of fruit-removal-dyn-amics tests on three different apple cultivars to determine the
forces required for robotic thin-ning.
The apple crop is a high-value agricultural commodity in the US, with an annual total production of nearly 10 billion pounds and valued at nearly $3 billion.
Prof He, a leader in agri-cultural robotics research, pre-viously developed automated components for mushroom pick-ing and apple tree pruning.
Green-fruit thinning – the process of discarding excess fruitlets in early summer, mainly to increase the remaining fruit size and quality – is one of the most important aspects of apple production.
“Eventually, in the next decade, we hope, this end effector will be combined with a machine vision component and a locomotion system, creating a mechanism that eventually will be able to accomplish robotic green-fruit thinning in apple orchards,” he said.
“I realize this sounds wildly futuristic, but I think this is where we are headed, sooner than later, and this end-effector was the needed first step.”
Prior to designing the end-effector, lead researcher Magni Hussain, a doctoral degree student in the Department of Agricultural and Biological Eng-ineering, performed a series of fruit-removal-dynamics tests to determine the forces required for robotic thinning, using pulling or stem-cutting methods on three different apple cultivars.
The work was done at Penn State’s Fruit Research and Extension Center in Biglerville, in south-central Pennsylvania.
After finding that fruit removal using the pulling method re-sulted in a high occurrence of spur-end stem detachment – which can leave a wound that affects neighbouring fruits in a cluster – Mr Hussain built a stem-cutting end-effector prototype and conducted extensive field tests.
He tested two end-effector prototype configurations: one
placing the end-effector on a handheld bar; the other integrating the end-effector with a robotic manipulator.
Prof He and Mr Hussain are already looking to the next stage of the research and the work is complex.
Mr Hussain is now working on the machine-vision component of the overall robotic system, “trying to design it from the ground up, so to speak,” he said.
The challenge is significant, he conceded, because for such
a vision system to work, there
are several components to con-sider.
“First and foremost, it has to detect green fruit, and I’ve implemented a deep-learning algorithm into the system to enable it to not only detect the green fruit in a tree environment, but also generate their pixel masks,” Mr Hussain said.
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