Controls development for the pallet handling device
This thesis reports the automated controls development, hardware design, and construction of a working scale model Pallet Handling Device (PHD) prototype. The PHD concept was patented by Stewart in 1995. The scale PHD is a 5-axis robot that can autonomously load pallets into a scale Over-the-Road (OTR) trailer. The PHD is controlled using a Programmable Logic Controller (PLC). To load a trailer the PHD first makes a scan of its workspace using ultrasonic sensors. The results of this scan are mathematically manipulated into trajectory commands to place pallets two wide per row, for the length of the trailer. The major challenge to overcome in this thesis was that the trailer to be loaded may be oriented such that it is offset or skewed with respect to the PHD. Another challenge was the hardware development. This included actuator design, electrical controls, and sensor interfaces. The scale model PHD successfully demonstrated that it can load an empty trailer with pallets even if the trailer is offset, skewed (or even pitched). One interesting result was that when loading a skewed trailer, the PHD successfully manipulated the pallets (in a stepped fashion) to follow the angle of the skewed trailer wall. Through the work of this thesis, the developed scale-sized PHD prototype has been proven to be successful, reliable and accurate.
School Location:USA - Ohio
Source Type:Master's Thesis
Keywords:pallet handling device over the road programmable logic controller
Date of Publication:01/01/1999