Sensing and end-effector for a robotic tomato harvester

Fresh produce is important for long-term space missions. It provides valuable nutritional needs and psychological boost for mission crews. Labor requirements to grow and harvest the crops, however, must be reduced through automation to allow the crew to perform other tasks. A robotic tomato harvester was developed for continuous, selective picking of mature tomatoes. The goal of this project was to develop a sensing unit and a robotic hand unit that could be integrated with a commercial robotic manipulator for the automated tomato harvesting task. Image processing algorithms were developed to determine sizes and locations of mature tomatoes including the ones that are partially occluded by leaves and/or branches. An end-effector subsystem, including a four-finger prosthetic hand and an embedded hand controller, was designed and assembled for the tomato picking, holding and placing task. Improvement of a previously designed robotic hand resulted in a 50% weight reduction. The sensing and picking capability of the units has been demonstrated in laboratory and commercial greenhouse environments. Success rates of tomato fruit sensing and picking were better than 95% and 85%, respectively.