  Human-robot collaboration has significant potential in recycling due to the
wide variation in the composition of recyclable products. Six participants
performed a recyclable item sorting task collaborating with a robot arm
equipped with a vision system. The effect of three different levels of human
involvement or assistance to the robot (Level 1- occlusion removal; Level 2-
optimal spacing; Level 3- optimal grip) on performance metrics such as robot
accuracy, task time and subjective fluency were assessed. Results showed that
human involvement had a remarkable impact on the robot's accuracy, which
increased with human involvement level. Mean accuracy values were 33.3% for
Level 1, 69% for Level 2 and 100% for Level 3. The results imply that for
sorting processes involving diverse materials that vary in size, shape, and
composition, human assistance could improve the robot's accuracy to a
significant extent while also being cost-effective.
