Workability and productivity of robotic plug transplanting workcell

Abstract

Transplanting is a necessary operation in transplant production systems. Transplanting operation is labor-intensive and automation can reduce labor costs. Plugs are actively growing young transplants with two well-defined morphologic parts: the stem-leaf portion and the root-growth medium portion. They may be grown in regularly situated cells on traylike containers. This regularity makes plugs suitable for automated transplanting operations. It is, therefore, beneficial for in vitro plant propagation systems to include plugs as intermediate products before they are delivered to the greenhouses. Flexible automation and robotics technologies have been applied to develop a robotic workcell for transplanting plugs from plug trays to growing flats. Main components of the workcell include a robot, an end-effector, and two conveyer belts for transporting trays and flats. The end-effector for extracting, holding, and planting plugs is a “sliding-needles-with-sensor” gripper. The sensor signals the robot to complete a transplanting cycle only when a plug is properly held by the gripper. Systems analysis and computer simulation were conducted to study factors affecting workability and productivity of various workcell designs. These factors included: dimensions and kinematics of the robot and its peripheral equipment, layout and materials flow, fullness of plug trays, and successful extraction rate of plugs. The analysis also indicated that machine vision systems could add valuable capabilities to the workcell, such as robot guidance and plug quality evaluation. Engineering economic analysis was performed to investigate the interaction of workcell technical feasibility and economic viability.