World’s first pepper-picking robot heralds new era

Globally, sweet peppers are produced to the tune of 26 million metric tonnes, with Europe’s crop alone worth over EUR 370 million in 2010. However, picking the fruit is labour-intensive. 

‘A human is very intelligent, and it is very difficult to replace a human being by a robot,’ explained Dr Jan Bontsema, from Wageningen UR Greenhouse Horticulture in the Netherlands.

One reason for creating a robot to do this is that robots do not risk contaminating the fruit, unlike human fruit pickers.

The pepper-picking robot, which runs on a rail system across a greenhouse, has a snake-like arm with pincers. To harvest a pepper, it first uses cameras to find a pepper. Once a target has been identified, its colour is analysed to tell if it is ripe, and the robot begins to move its articulated arm. 

The robot developed by the EU-funded CROPS project, which Dr Bontsema coordinates, uses a continuous stream of snapshots to direct its movements, until it has grasped the fruit and removed it with a retractable cutter.

For years researchers have been working on robots that can harvest cucumbers and tomatoes, however there has been very little work on sweet peppers, even though they are an important part of our diet.

However, while the robot developed by the CROPS project could successfully pluck ripe peppers, it did so at a leisurely pace at odds with the efficient, profit-driven world of modern farming and only worked if the fruit was clearly visible. 

Replicating the dexterity of human hands has been a challenge. Credit: Wageningen UR Glastuinbouw.

Real-life situation 

Now Dr Bontsema is coordinating a follow-up project – SWEEPER – which aims to make the robot ready for commercialisation by increasing its speed and enabling it to pick peppers in a real-life situation.

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‘A robot system will improve food safety and give the opportunity to selectively harvest for higher quality.’

‘If you look at the crop, you’ll see it’s a jungle – so many leaves, and here and there are fruits. And that is the problem,’ said Dr Bontsema.

To solve this, they’re working to make the robot smarter. ‘We introduced in CROPS the so-called ROS software, robot operating system and we will continue this in SWEEPER,’ he said. ‘With that software you get a kind of plug and play system so if you want to use a different camera, for example, it’s no problem at all.’

The pepper-picking robot is part of an acceleration in the development of agricultural robots - the European RHEA project has also developed a fleet of robots capable of protecting crops with their weeding and spraying skills.

The team, led by Dr Angela Ribeiro at the Spanish National Research Council, hopes that one day the use of chemical pesticides and herbicides on farms could be significantly reduced thanks to robots like the ones they have developed, which continually monitor and remove weeds from fields.

The green-fingered robots look like miniature tractors, and are controlled by a central computer unit which keeps track of their position, orientation, speed, and status and directs them in real-time.

Global positioning systems, geographic information systems, and continual sensing allow the robots to navigate their environment and carry out precision tasks.

There are three models; a fire-breathing weeding robot directed by keen-sighted drones, a robot for spraying chemicals on rows of crops, and one for spraying trees.

‘Most of the technology developed within the RHEA project could be ready in a few years,’ Dr Ribeiro said. ‘Although the market penetration may take longer, mainly due to the technical skills that farmers need.’