Abstract:
The present study is aimed at
determination of the super-elliptic shape of
tire-soil contact area using image processing
method. Contact area has a substantial role
on determination of soil compaction and
tractive parameters of agricultural tractors.
A very well-known model in this realm is to
describe the contact area with superellipse
geometry. A soil bin testing facility
equipped with a single-wheel tester was
utilized to conduct the needed experiments.
The experiments were carried out at three
levels of wheel load, three levels of tire
inflation pressure with three replicates in a
completely randomized block design.
Corresponding images were taken for each
of the experiments and the images were
processed accordingly. The contact length
and width were determined using imdistline
command in MATLAB commercial
software. This experiment was conducted at
three levels of wheel load (2, 3, and 4 kN),
and three levels of tire inflation pressure
(100, 200, and 300 kPa) with three
replications. The aforementioned parameters
were applied consequently in the
superellipse model and the contact area was
computed. The obtained results disclosed
that increase of wheel load increases the
contact area. Contradictory, increment of
tire inflation pressure reduces the formed
contact area. Additionally, the potential of
contact area determination with the
proposed model was compared with that of
actual values, which denoted coefficient of
determination equal to 0.96, which shows
the promising ability of the proposed model
and the appropriateness of describing
contact area with superellipse geometry.
