Performance evaluation of harvesting robot for heavy-weight crops

Abstract

A harvesting robot for heavy-weight crops (HRHC) was developed and evaluated in this study. This robot consists of a robot tractor as a mobile platform, a specifically developed robotic arm for this application, a developed end-effector for pumpkin, and a controlling system. The final evaluations were focused on eight parameters including working space, system resolution, harvesting possibility zone, accuracy, repeatability, harvesting success rate, cycle time, damage rate. The results showed that this robot has harvesting success rate and damage rate of 92% and 0%, respectively. The average cycle time in scenarios 1, 2, and 3 were 58.7s, 41.9s, and 35.1s, respectively. The workspace parameters of a final system including the workspace volume, harvesting surface, and harvesting length were 5.662×109 mm3, 2.86×106 mm2, and 800 mm, respectively, which was 70.6, 81.3, and 99%, of required parameters in the designed system, respectively. The accuracy and repeatability were 4.5, and 5.23 mm, respectively. The system resolution in x, y and z directions were 1 mm, which had a tolerance of 75, 50, and 25 μm, respectively. These results indicate that the system has enough motion resolution, accuracy, and repeatability for harvesting pumpkins. The HCRH system harvest success (100%) was higher than overall average harvest success of previous studies between 1984 and 2012. In during of experimentations no fruit damage was detected. The experiments output meets the determined requirements and the HCRH system found applicable to harvest pumpkin in the field.