Minimising the non-working distance travelled by machines operating in a headland field pattern

When treating an area of field using agricultural equipment, the field is usually traversed by a series of parallel tracks using a pattern established by the experience of the operator. At the end of each track the process is constrained by the ability of the operator to distinguish the next track to be followed. The introduction of commercially available auto-steering or navigation-aid systems for agricultural machines has made it possible to upload arbitrary field pattern sequences into programmable navigational computers and for the machines to follow them with precision. This new technology also offers a new perspective for improving machine field efficiency, since not all field traversal sequences are similar in terms of total non-working distance travelled. This paper presents an algorithmic approach towards computing traversal sequences for parallel field tracks, which improve the field efficiency of machines by minimising the total non-working distance travelled. Field coverage is expressed as the traversal of a weighted graph and the problem of finding an optimum traversing sequence is shown to be equivalent to finding the shortest route in the graph. The optimisation is formulated and solved as a binary integer programming problem. Experimental results show that by using optimum sequences, the total non-working distance can, depending on operation, be reduced by up to 50%. (C) 2008 IAgrE. Published by Elsevier Ltd. All rights reserved.