On the face of it, robots should be good at picking and packing online supermarket orders – it's repetitive work, and very little decision making is required for most items. Unfortunately, most robotic manipulators can't be trusted with odd-shaped, easily bruised fruit and vegetables. To address this problem, online supermarket Ocado has been putting new soft manipulation robots to the test in its European warehouses.

Ocado's testing is a part of the SoMa research project, a collaboration between a number of universities and research institutes in search of simple, robust robot manipulation systems that are also flexible enough to handle fragile goods. If that wasn't challenging enough, the gripper also needs to work flawlessly with items of various different shapes and sizes.

One of the solutions being tested is the RBO Softhand 2, developed for the program by the Technical University of Berlin (TUB). Rather than running with solid, metal components, it uses flexible rubber materials and pressurized air to gently adjust its grip. It contains seven individually controllable air chambers all up, with an anthropomorphic shape chosen to allow the gripper to grip a wide range of objects.

This approach differs from one taken by EPFL, which uses electroadhesion to grip fragile objects, although the team at Harvard has developed a similar-looking soft-gripper for undersea exploration.

To make sure RBO Softhand 2 doesn't just crush the object in its grasp, the robotic hand is "highly under-actuated," which means only the air pressure being sent to fingers is controlled. The palm, fingers and thumb on the manipulator adjust their shape to match whatever it is they're picking up, a design touch chosen to make the hand easier to control.

In testing, the RBO Hand 2 was attached to two different robot arms, before being used to move artificial fruit stored in a regulation container. The manipulator successfully picked up a single object from the base of a container, with tests proving it was able to adjust to different shapes and sizes. Testing also showed, however, that the Hand was most successful when the container held the object it was lifting in place.

Following the successful initial tests, the team at Ocado will put the manipulator through a set of more difficult scenarios, adding more objects to the fruit container and playing around with the warehouse environment to make life easier for the RBO Hand 2.

Check out the robot in action below.

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