First robotic lettuce leaf peeling system revealed

Date:10-03-2018

AHDB student Luca Scimeca develops a new robot able to handle a very delicate manual task.

Due to the challenge of accessing affordable labour in the horticultural industry, growers are increasingly looking to robotic solutions that may help to take-on some of the labour intensive tasks within their business in the future.

Removing the outer leaves of lettuces after harvest is currently a manual task performed by farm workers.

Researchers at Cambridge University, including PhD student Luca Scimeca, have now successfully developed a new system that is capable of performing the peeling process with full leaf removal – 50 per cent of the time, with the process taking an average of 27 seconds to complete.

And while this task may be easy for humans to achieve, for robots it is a challenging vision and manipulation task and which has so far been difficult for robotic technologies to grasp.

The creation by the team, led by Dr Fumiya Iida, lecturer in Mechatronics, of a 3D-printed circular nozzle, mounted on the end of a robotic arm and tested with a suction system, acts as the single vacuum suction point. It is designed to grab a leaf and remove it from the main body of the lettuce using a tearing action, without causing damage to the produce.

Crucial to the accuracy of the leaf tearing is the use of computer vision to locate and determine the positioning of the lettuce. It does this by first detecting the lettuce stem with the aid of a 2D web camera placed directly above and within the assumed field of vision. In cases where the stem cannot be found, an action will be taken to flip the lettuce over by applying a horizontal force and rolling the lettuce with a soft pad attached to the robot arm. Better positioning of the lettuce can then be achieved with the outer leaf on top and with minimal risk of damage.

Luca Scimeca, from the Biologically Inspired Robotics Laboratory (BIRL), and funded through the AHDB studentship scheme, said: “Lettuce leaf peeling is an interesting robotics problem from an engineering perspective because the leaves are soft, they tear easily and the shape of the lettuce is never a given,” he said. “The computer vision we have developed, which lies at the heart of our lettuce peeling robot, can be applied to many other crops, such as cauliflower, where similar information would be required for the post-processing of the produce.”

To find out more about the exciting technological developments happening in horticultural, book on to the SmartHort 2019 conference, 6 – 7 March. Book now.

You can find out more about Luca’s AHDB-funded project, ‘Robotic touch, sense, and learning of delicate vegetables’ here.