International Commission of Agricultural and Biosystems Engineering
Abstract
Two off-the-shelf John Deere utility mowers were modified for X-by-wire control for the
purposes of constructing autonomous vehicles usable in sports-turf mowing applications. The
purpose of these mules was to enable the gathering of requirements and customer feedback on
such a system. The environment selected initially was that of a baseball stadium. These areas can
be characterized as flat, highly controlled and well-groomed, for which precise mowing patterns
are necessities.
Typically the operators of these mowers are highly skilled; an autonomous system has the
benefits of saving time and labor, permitting the efficient usage of less-skilled employees, and
allowing skilled personnel to focus on more complex tasks (such as infield mowing and warning
track grooming).
For this application, there are stringent requirements on navigation, path planning and path
tracking, while the safeguarding requirements are challenging, but more relaxed than, say, the
requirements for golf courses. The calculation of precise position and orientation in this
environment requires sensor fusion and is complicated by the fact that frequently the operating
area is surrounded by very high walls, limiting sky visibility and preventing the usage of GPScentric
navigation systems. Furthermore, it was desirable to mature the design far enough so that
it could be operated regularly by non-technical operators. These results were achieved by
developing an accurate local positioning system, making the hardware and software subsystems
robust against unexpected failures and constructing a very simple graphical user interface.
This paper will review other relevant existing systems, describe the hardware and software
systems utilized, and conclude with descriptions on the performance, customer learning, and
description of properties of autonomous systems that enable their integration into a worksite