the main purpose of this study was to estimate the market demand of tractor stock in africa, west asia and other target markets for iran manufactured tractors. box and jenkins, and exponential smoothing methods were applied, using data from 1961 to 2006. results indicated that demand for tractor stock in the target markets will be approximately 533 thousand sets in 2012 and consequently the ann...

The multiple benefits of automating steering in agricultural vehicles have resulted in various autoguidance systems commercially available, most of them relying on satellite-based positioning. However, the fact that farm equipment is typically oversized, heavy, and highly powered poses serious challenges to automation in terms of safety and reliability. The objective of this research is to impr...

In this paper we relate the Fefferman–Graham ambient metric construction for conformal manifolds to the approach to conformal geometry via the canonical Cartan connection. We show that from any ambient metric that satisfies a weakening of the usual normalisation condition, one can construct the conformal standard tractor bundle and the normal standard tractor connection, which are equivalent to...

Automatic control of agricultural vehicles has been a research goal for many years. Previous attempts have failed largely due to sensor limitations. With the advent of modern GPS receivers, a single low-cost sensor has been synthesized in which centimeter-level position and attitude measurements of the vehicle state are available using Carrier-Phase Differential Global Positioning System (CDGPS...

We propose several schemes to realize a tractor beam effect for ultracold atoms in the vicinity of a few-mode nanowaveguide. Atoms trapped near the waveguide are transported in a direction opposite to the guided mode propagation direction. We analyse three specific examples for ultracold (23)Na atoms trapped near a specific nanowaveguide (i.e. an optical nanofibre): (i) a conveyor belt-type tra...

In a ®eld trial (1985±1996) on a sandy loam soil the effects of tractor traf®c and fertilisation on earthworm populations were investigated. The tractor traf®c treatments compared normal farm practice (`normal') with reduced tractor traf®c (`low'). In the fertilisation treatments, three different cattle-manure management methods were compared. The cattle manure was applied as diluted slurry, as...

There is a well known one–parameter family of left invariant CR structures on SU(2) ∼= S. We show how purely algebraic methods can be used to explicitly compute the canonical Cartan connections associated to these structures and their curvatures. We also obtain explicit descriptions of tractor bundles and tractor connections.

Trailer reversing is a problem frequently considered in the literature, usually with fairly complex non-linear control theory based approaches. In this paper, we overview our simple method for stabilizing a tractor-trailer system to a trajectory based on the notion of controlling the hitch-angle of the trailer rather than the steering angle of the tractor. The performance of this control method...

In the context of precision agriculture, we have developed a machine vision system for a real time precision sprayer. From a monochrome CCD camera located in front of the tractor, the discrimination between crop and weeds is obtained with image processing based on spatial information using a Gabor filter.This method allows to detect the periodic signals from the non-periodic ones, and enables u...

Nacrtak Mechanized felling was introduced in Slovenia at the beginning of this decade, and before that Slovenian forestry relied on motor manual felling and tractor skidding or cable crane yarding. In this research we are dealing with wood forwarding. Model skidding maps were built, using terrain classification and decision support systems for forwarders and tractor trailers. The purpose of thi...