Degree Type


Date of Award


Degree Name

Master of Science


Agricultural and Biosystems Engineering


Agricultural and Biosystems Engineering

First Advisor

Matthew J. Darr


Automation of new applications has become a major focus of the agricultural machinery industry in recent years. Automation technologies are able to improve productivity, efficiency, and the operator experience. Original equipment manufacturers use automation to market new equipment and offset the added cost of Tier IV engines incurred by the customer. To advance automation, new applications are being explored.

During harvest, combines must frequently be unloaded to make room for more crop intake. Large farming operations will normally perform the unloading process on-the-go, meaning that crop harvesting will continue while grain is unloaded into a grain cart towed by a tractor in parallel with the combine. Manual unloading on-the-go is stressful, because the combine operator must divide his/her attention between unloading and the normal harvesting tasks (steering, speed control, crop intake, and monitoring machine performance).

Automating the unloading process has the potential to reduce operator stress and improve in-field productivity. John Deere has recognized this potential and partnered with Iowa State University to develop the SmartUnload system. One requirement of an automated unloading system is a means of actuating to control the location of the auger boot within the grain cart.

The primary goal of this work was to develop an auger-swing control system as the primary means of actuation. The response characteristics of the original auger system as well as a proportional solution were investigated and the corresponding in-field performance evaluated. Results indicate that on-off and proportionally controlled auger swings are effective means of actuation for the automated unload system. Proportional control significantly improves control precision, allowing for smoother fill profiles and better grain cart utilization.

Future work should be completed to integrate production-intent proportional hardware. Implementing a more advanced control, such as gain-scheduled proportional control, with a more discrete fill strategy would further improve auger-swing fill performance. For the auger system studied, swinging out had a slightly different response than swinging in; more consistent performance could be possible by implementing a separate control function for each swing direction.


Copyright Owner

Benjamin Charles Potter



File Format


File Size

139 pages