Reaching for Automated Stacking - A Preliminary Study on Automation of a Reach Stacker

Abstract: This is the report for a master thesis work which concerns the challenge of automating a reach stacker. A reach stacker is a vehicle that lifts and moves containers. This report should be seen as a preliminary study which handles automation concepts, simulations and sensors. Research questions answered are: Which areas would benefit most from driver assistance, What kind of control is needed for these systems and Can an automated system with this setup be faster than a human operator? The path leading up to the concepts regarding the automation follows Karl T. Ulrich and Steven D. Eppingers methodology for Product Development. The chosen concepts are evaluated with models built in Simulink, a Matlab plug-in. An automated reach stacker needs sensors for mapping its surroundings, suitable sensor technologies and placement are therefore presented. Two concepts were chosen to be simulated, one picks a container up and the other drops it down. A reach stacker uses hydraulics to lift a container, therefore the simulation model contains both mechanical and hydraulic parts. The model calculates the new position by measuring the distance to the goal position and then moves there with the help of controllers. The simulation results are presented with times and travelled distance. These results was at first not as good as was hoped for, but after the work was finished new information was revealed which would lead to much better results. Problems with the design of the Simulink model, such as not seeing the compiled hydraulic part and the affect the actuators has on each other are discussed.