Next chapter in the history of apples

Hugh Zhou (PhD student), Dr Chao Chen (senior lecturer at Monash), Dr Wesley Au (research fellow) and Mr Xing Wang (PhD student) pose with 'Billy', the robotic harvester. Photos: SHELBY BROOKS

By Shelby Brooks

The humble apple has found itself in the centre of literature and folklore since its domestication in Central Asia thousands of years ago.

Think the forbidden fruit in the Garden of Eden, Issac Newton’s apple tree which helped him come up with the theory of gravity and of course, the poison apple in the tale of Snow White.

Now though, apples grown in Drouin are part of a new story, a story about robotic apple picking.

On first thought an apple picking robot sounds bizarre.

But the Australian apple industry, like many fruit and vegetable producers, is experiencing chronic labour shortages brought on by Covid-19.

Led by Dr Chao Chen from Monash University’s Department of Mechanical and Aerospace Engineering, a research team has found a way to combat labour shortages and the increased demand for fresh produce.

An autonomous harvesting robot, capable of identifying, picking and depositing apples, is currently being trialled at Fankhauser Apples in Drouin, funded by the ARC Nanocomm Hub (IH150100006).

“We see that there is a need from Australian farmers, that there is a shortage of labour on farms,” Dr Chen said.

“Every year, the orchard owner relies on the backpacker to come pick the fruit during harvest season.

“So we think that a robotic system can do the job for the farmers.”

The robot has a vision system which positively identifies apples ready for picking based on their redness, while also looking out for leaf and branch obstacles which could impede on the optimum trajectory of the apple extraction.

“It takes just eight seconds to plan the entire trajectory for the robot to grasp and deposit an apple,” Dr Chen said.

In comparison, humans can pick an apple in four seconds.

“But we are only running about 40 per cent capacity at the moment,” Dr Chen said.

“So the speed can be dramatically increased.”

Monash University research fellow Dr Wesley Au suggested calling the machine Billy, a nickname derived from the story of William Tell, the skilled archer who earned his freedom by successfully shooting an arrow through an apple balanced on the head of his son.

‘Billy’ can work in all types of lighting and weather conditions, including intense sunlight and rain, and takes less than 200 milliseconds to process the image of an apple.

“The robot can work in all different types of weathers,” Dr Chen said.

“A human doesn’t want to work at night. A human doesn’t want to work in rain conditions.”

The robot grasps the apple with a soft gripper made from four independently actuated ‘fingers’ and a suction system that minimises damage to the fruit and the tree itself.

Of all apples harvested, less than 6 per cent were damaged due to stem removal.

Apples without stems can still be sold, but don’t necessarily fit the cosmetic guidelines of some retailers.

So far, the Drouin trial has found that the robot was able to harvest more than 85 per cent of all reachable apples in the canopy as identified by its vision system.

Brad Fankhauser, fifth generation Australian apple grower and general manager of Fankhauser Apples in Drouin, said he was sceptical when the team first brought the robot to his farm in March.

“They said they wanted to be commercial in five to eight years and I thought you’re dreaming!” Brad said.

“Where they were six weeks ago when they arrived to where they are now is phenomenal.

“Today, you can see it happening in three to five years, I would say.”

Brad said usually the 100 acre farm would have around 25 overseas workers during harvest season.

This year, they have 15.

The possible introduction of robotic labour in the future wouldn’t see the complete eradication of human involvement, Brad said.

“Robots might only get to 75 to 80 per cent of capacity of your yield,” he said.

“So there is always going to be a requirement for someone to pick and you’re going to have to have someone here to run the machines.

“You might see a 50 to 60 per cent reduction in labour but you’re probably paying more because they have to be trained technicians to drive the robot.”

Overall, Brad is impressed.

“There are various groups around the world trying to achieve [robotic harvesting] and all different methods,” he said.

“This is impressive.”