Robots learn to pick the harvest

Supermarket customers prefer to purchase shiny red peppers and perfect apples. To ensure that fruit and vegetables arrive at the market ripe and without bruises, they are carefully and laboriously harvested by hand. Machines could work more quickly, but how does a machine find the fruit often hidden under leaves and then manipulate it? How does a machine know which fruits are ripe enough to pick?

Research project develops harvesting robot

The Clever Robots for Crops (CROPS) research project sponsored by the European Union Commission could provide a solution for an automated harvesting procedure. The aim is a configurable, modular, and intelligent robot platform that reliably recognizes the fruit as well as obstacles and other objects so it can navigate and harvest independently on farms and in greenhouses.

Apples and peppers as test objects

Researchers are concentrating on the harvesting of apples and peppers. “To start with, we cleared up which framework conditions to observe,” said Dr. Wolfgang Gauchel, Festo Research and CROPS project manager for Festo. “How strongly can the fruit be pressed with the gripping elements? What cutting strength is required? After four years of research work, we have now developed two prototypes. Both use an adaptive gripping technology that adjusts according to the fruit size and shape. With the adaptive fingers, we have been able to make an important contribution to the project.”

Adaptive gripping structures

The “pepper gripper” uses passively adaptive FinRay fingers. The “apple gripper” consists of membrane jaws filled with ceramic balls. The fruit is separated either by twisting and pulling or using a third finger, which presses on the apple’s stem.

Robot recognizes ripe fruit

The grippers are fastened on a robot, which uses cameras and other sensor technology not only to detect the position of the fruit, but also its ripeness. Only the really ripe fruit is therefore harvested, with semi-ripe and overripe fruit being left on the plant.

Submitted by: Frank Langro, Director – Marketing and Product Management, Festo Corp.