The principles of fruit picking robots have been developed since the early 1980's. These principles have opened up new approaches to the harvesting of crops. However, to fully develop the fruit picking robotics technology, contributions from high-tech industry, agricultural commodity groups and farm equipment manufacturers must be sought.
To start with, the fruit picking robots need to pick ripe fruit without damaging the branches or leaves of the tree. Mobility is a priority, and the robots must be able to access all areas of the tree being harvested. It goes then without saying that the robots must be 'intelligent', and have a human-like interaction with their surroundings through senses of touch, sight, and image processing. The fundamental blocks of these robots are shown in the diagram here.
The robot can distinguish between fruit and leaves by using video image capturing. The camera is mounted on the robot arm, and the colours detected are compared with properties stored in memory. If a match is obtained, the fruit is picked. If fruit is hidden by leaves, an air jet can be used to blow leaves out the way so a clearer view and access can be obtained.
The robot arm itself is coated in rubber to minimise any damage to the tree. It has 5 degrees of freedom, allowing it to move, in, out, up, down, and in cylindrical and spherical motion patterns. The pressur applied to the fruit is sufficient for removal from the tree, but not enough to crush the fruit. This is accomplished by a feedback process from the gripper mechanism, which is driven by motors, hydraulics, or a pneumatic system. The shape of the gripper depends on the fruit being picked, as some fruits, such as plums, crush very easily, while others, like oranges are not so susceptible to bruising.
The robots should have access to all areas of the orchard in order to reach all of the fruit.