Watch: Engineers develop lettuce-picking robot

The development of a robot which can harvest lettuces using machine learning is being seen as a major step forward in the use of robotics in the agriculture industry.

The Vegebot has been developed by a team of researchers at the University of Cambridge in the UK.

While crops such as potatoes and wheat have been harvested mechanically at scale for decades, many other crops, including the iceberg lettuce, have to date been too challenging.

Although it is the most common type of lettuce grown in the UK, iceberg is easily damaged and grows relatively flat to the ground, presenting a challenge for robotic harvesters.

The Vegebot uses an overhead camera to photograph a section of a field of lettuce. The image is then analysed to identify which lettuces are ripe for picking and which are diseased and should be avoided.

It's hoped the technology could been used for  many other crops.
It's hoped the technology could been used for many other crops. Photo credit: Supplied

A second camera on the Vegebot is positioned near the cutting blade and helps ensure a smooth cut, by the robotic arm. 

The researchers are also able to adjust the pressure in the robot's gripping arm so that it held the lettuce firmly enough not to drop it, but not so firm as to crush it

Although the prototype is nowhere near as fast or efficient as a human worker, Simon Birrell from Cambridge's Department of Engineering said it  demonstrated how the use of robotics in agriculture might be expanded, even for crops like iceberg lettuce which are particularly challenging to harvest mechanically.

"Every field is different, every lettuce is different," he said

"But if we can make a robotic harvester work with iceberg lettuce, we could also make it work with many other crops."

Research lead Dr Fumiya Iida said it was hoped the new technology could be used on other crops. 

"We wanted to develop approaches that weren't necessarily specific to iceberg lettuce so that they can be used for other types of above-ground crops," he said.

In future, it's thought robotic harvesters could help address problems with labour shortages in agriculture, and could also help reduce food waste. 

At the moment, each field is typically harvested once, and any unripe vegetables or fruits are discarded. However, a robotic harvester could be trained to pick only ripe vegetables, and since it could harvest around the clock, it could perform multiple passes on the same field, returning at a later date to harvest the vegetables that were unripe during previous passes.

"We've still got to speed our Vegebot up to the point where it could compete with a human, but we think robots have lots of potential in agri-tech."

Iida's group at Cambridge is also part of the world's first Centre for Doctoral Training (CDT) in agri-food robotics

In collaboration with researchers at the University of Lincoln and the University of East Anglia, the Cambridge researchers are training the next generation of specialists in robotics and autonomous systems for application in the agri-tech sector.