Research Paper Reducing field work time using fleet routing optimization Hasan Seyyedhasani * , Joseph S. Dvorak Biosystems and Agricultural Engineering Department, University of Kentucky, 128 C.E. Barnhart Building, Lexington, 40546-0276, USA article info Article history: Received 7 March 2017 Received in revised form 8 October 2017 Accepted 17 January 2018 Keywords: Agricultural operation Path planning Computer model Optimized routing Field completion time Agricultural producers seek to complete their field work operations as quickly as possible. This is achievable through the simultaneous use of multiple vehicles for an operation. However, path allocation and scheduling then must be considered. Transforming the field work problem into a Vehicle Routing Problem (VRP) and using optimization procedures designed for this problem provides a method of allocating paths. In this work, the accuracy of a VRP representation of field work is confirmed and the ability of this optimization system to reduce field work times is verified. Experiments were conducted using three tractors during a rotary mowing operation. First, the traditional routes used by human drivers were recorded. Then, a VRP representation of this operation was created, and new routes generated by a Tabu Search optimization procedure. Finally, the field operation was repeated using the optimized routes. Using these routes, the time to complete the field work was reduced by 17.3% and the total operating time for all tractors was reduced by 11.5%. The predictions by the VRP representation for completion time and total time were both within 2% of the actual times recorded when the tractors followed the computer- generated routes in the field. These reductions illustrated the ability of the route optimi- zation procedure to improve effective field efficiency. © 2018 IAgrE. Published by Elsevier Ltd. All rights reserved. 1. Introduction Agricultural producers seek to complete their field work op- erations as quickly as possible. This drive to increase field capacity, the rate in terms of area per time that work is done (American Society of Agricultural and Biological Engineers, 2011), has led to larger agricultural machinery and many producers to use more than one machine in a field at a time. It has also led researchers to seek methods to improve the effi- ciency of these field operations. Many researchers have tested methods to improve the way in which paths are generated in fields. Other projects have focused on the order in which these paths are worked and, in the case of multiple vehicles, which vehicles are assigned to each path. One issue with these improved path generation and routing systems is that the solutions they generate often appear random and arbitrary. These solutions do not follow any easily recognizable rule. However, modern advances in sensing, information and communication technologies have provided automatic steer- ing and navigation systems that enable following these more * Corresponding author. Fax: þ1 859 257 5671. E-mail addresses: hshasaniT@uky.edu (H. Seyyedhasani), joe.dvorak@uky.edu (J.S. Dvorak). Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/issn/15375110 biosystems engineering 169 (2018) 1 e10 https://doi.org/10.1016/j.biosystemseng.2018.01.006 1537-5110/© 2018 IAgrE. Published by Elsevier Ltd. All rights reserved.