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Robotics Research
Posted on November 29, 2017

Experimenting with robots for grocery picking and packing

Over the past couple of years Ocado Technology have announced their involvement in several high-profile research projects, including the SoMa soft manipulation system and the SecondHands technician cobot.
 
This is because their robotics research team faces a remarkable challenge: to develop smart and generalised robotic solutions and systems capable of picking the 50,000 different items available on Ocado.com safely and reliably. While humans can quickly learn and develop all manner of strategies for grasping various items based on what they intend to do with them, robots need to be taught these strategies and that's why AI plays such an important role too. Since this ever-growing range of products has different form factors and physical properties, the SoMa and SecondHands projects will help develop a new suite of robotic grippers and grasping strategies in partnership with Europe's leading technical universities.
 
While making significant progress on those projects, Ocado Technology are also developing more immediate in-house solutions using off the shelf components that can pick a significant proportion of their products.
 
A system below has been designed by the robotics research team to pick a range of groceries from the highly automated warehouses called Customer Fulfilment Centres.
 
How it works
To begin with, Ocado Technology considered the complexity and fast-moving nature of their grocery picking process. When you take into account that they fulfil an average of 260,000 orders per week, any automated system had to be capable of picking a vast range of differently shaped objects (catalogue now includes more than 50,000 SKUs), in any orientation, when stored in a crate with many other objects. This level of complexity is unique to a grocery warehouse, so who better than the Ocado Technology robotics team to appreciate the constraints and challenges any purpose-built system would need to overcome?
 
Their new solution is conceptually simple in its design when you compare it to the scale of the task it has been built for. The robot consists of a suction cup on the end of an articulated arm. The arm is equipped with a pipe running to an air compressor, which is capable of lifting items regardless of their deformability and shape, as long as they are within the weight restriction and the suction cup can create an airtight seal with the item's surface (i.e it has a big enough surface available and is not porous).
 
The system is designed to be easily integrated with the pick stations present in Ocado's highly automated Customer Fulfilment Centres. These pick stations use an assembly line system where crates of products are delivered by conveyors to a picking point.
 
Once the storage crates arrive at the pick station, the job of the robot system is to transfer however many items are needed from the storage crates into the delivery crates destined for the customer. In order for this process to run smoothly, the algorithm controlling the robot needed to have an understanding of where the crates were located and of the optimal grasp points of the items within the crate. Additionally, it must search for free space in the delivery crate so it can pick and place multiple products in the same order. This may sound simple, but developing the robot's understanding of its surroundings is very challenging.
 
Ocado Technology could have embarked on a mission to model every single item in their catalogue, but knew there must be a quicker and more efficient method. The team developed the prototype using a 3D vision system that could identify the optimal grasp points that relate to picking one item at a time out of a full crate. The suction cup could then be lowered down to the designated grasping point to securely pick it up and transfer it to the delivery crate. Along the way, the system verifies that the item is the correct product, and determines the optimal orientation to rotate it to, before placing it into the bag.
 
Built-in sensors avoid the risk of crushing or damaging during picking. The same technology is also used when placing the picked item into the customer crate to avoid items already packed being crushed by other incoming items. Finally, the system also ensures that the items are only released if they can be placed without protruding from the delivery crate.
 
The fact that the team found a way to bypass modelling their SKUs also meant that they could pick a greater range of items than many industrial picking systems. All in all, the system is streamlined and flexible, and the robotics team are very proud of the progress they have made so far.
 
 
Source and top image: Ocado Technology
Learn more at the next leading event on the topic: Sensors Europe 2019 External Link on 10 - 11 Apr 2019 at Estrel Convention Center, Berlin, Germany hosted by IDTechEx.