Application of geometric constraint programming to the kinematic design of three-point hitches
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Date
2007-01
Authors
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Journal ISSN
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Publisher
American Society of Agricultural and Biological Engineers
Abstract
Design of three-point hitch systems used with agricultural tractors is quite evolved and is governed by an established standard. Freedom within the standard, though, can be exploited to tailor the individual hitch performance. A hitch can be treatedas a four-bar linkage in the vertical longitudinal plane, yet it presents a complicated kinematic synthesis problem because the constraint set imposed by the standard is large and complex. This article proposes the use of Geometric Constraint Programming (GCP) as a design tool to address this problem. GCP uses the drafting mode of commercially available parametric CAD software to impose geometric constraints on objects to define kinematic diagrams. The software then allows the manipulation of the design parameters of the mechanism while the diagram is dynamically updated to satisfy all imposed constraints. GCP is particularly effective in three-point hitch design since a graphical representation of the complex constraint set is obtained, enabling real-time visualization of the interactions between constraints and the effects of varying various design parameters on the design solution. An example is presented to demonstrate the technique, and geometric insight in the form of an implied constraint is uncovered for the chosen model, highlighting the strength of the approach.
Description
Keywords
three-point hitch, agricultural tractor hitch, kinematic design, geometric constraint programming
Citation
S. S. Ambike and J. P. Schmiedeler, "Application of geometric constraint programming to the kinematic design of three-point hitches," Applied Engineering in Agriculture 23, no. 1 (2007)