Division of Information Technology, Engineering and the Environment
Agricultural Machinery Research Design Centre
Agricultural Machinery Research Design Centre
Optimising the performance of an oscillatory subsoiler.
Many Australia vineyards suffer from deep soil compaction, created
either naturally or by trafficking, this can prevent root growth to
desirable depths and limit access to water and nutrients. A prototype
low frequency, high amplitude, dual time oscillating subsoiler was
developed, suitable for 70kW lightweight vineyard tractors.
This study aimed to determine the most efficient settings of the
oscillating time parameters and optimise the performance of the tractor-subsoiler
system. A series of field experiments were conducted to quantify the
effect of tine oscillation frequency. Amplitude and oscillation angle on
subsoiler performance and tractor vibrations.
The velocity ration, defined conventionally as a function of
oscillation frequency, amplitude and tractor travel speed was modified
to additionally account for the effect of tine oscillation angle. Past
work using high frequency-low amplitude oscillating tool systems
describe the oscillation cycles for a velocity ratio more than 1 as
comprising of 3 consecutive phases of soil cutting, backing off and
catching up for the tool active (upper) face.
A theoretical framework describing the dynamic characteristics of
oscillatory subsoilers was developed. The concept of resultant velocity,
dynamic rake angle and dynamic scrubbing angle was presented. This
theoretical framework validated the conventional 3 phase model for
velocity ratios greater than one (λ =1-3) and negative oscillation angle
of -2ε to -25. With oscillation angles (β>-2ε) the three basic phase
theory did not hold true, as the catching up phase was replaced by soil
cutting.
Significant soil/tool interaction generating compaction and
influencing the dynamics of the forces was observed to occur on the
underside of the tool tip for velocity ratios more than 0.6 with
positive oscillation angles (β>-2ε). IN the case of velocity ratios
greater than one, tool underside scribbing also occurred with negative
oscillation angles less than -25. At velocity ratios more than 6
underside engagement occurred for all oscillation angles.
Shahgoli G, Saunders C, Desbiolles J and Fielke J. An investigation into the performance of vibratory tillage using straight and bent leg tines. Advances in GeoEcology 38: Soil Management for Sustainability. Chapter 1: Soil Dynamics and Traction. Editors Horn R, Fleige H, Peth S and Peng X. Catena Verlag Gmbh, Germany. 2006 pp. 21-30.
G. Shahgoli, C. Saunders, J. Desbiolles and J. Fielke. An investigation into the performance of oscillatory tillage using different frequencies. Proceedings of the Biennial Conference of the Australian Society for Engineering in Agriculture (SEAg), September 2007, Adelaide, South Australia. p.154-166
G. Shahgoli, C. Saunders, J. Desbiolles and J. Fielke (2007). The effect of oscillation angle on the performance of oscillatory tillage. Proceedings of the Biennial Conference of the Australian Society for Engineering in Agriculture (SEAg), September 2007, Adelaide, South Australia. p.167-178
G. Shahgoli, C. Saunders, J. Fielke and J. Desbiolles (2007).
Simulation of the dynamic behaviour of a tractor-oscillating subsoiler
system. Proceedings of the Biennial Conference of the Australian Society
for Engineering in Agriculture (SEAg), September 2007, Adelaide, South
Australia. p.179-189.
