HighlightsModeling provides the relationships between path, kinematics, geometry, and towed implements.Linear interpolation allows trajectories to be compared if data recording is random.Correction coefficients can be a solution to compensate for soil resistance.Abstract. Automatic guidance systems and autonomous vehicles require tested methods of path generation to ensure successful maneuvers (such as automatic trajectory correction and headland turn management). In this study, an evolution of Zakin’s kinematic modeling, as applied in the automobile industry, is proposed for an agricultural poly-articulated vehicle (representing a tractor or other type of towing vehicle with one or more towed implements attached with an articulated hitch). Geometry, vehicle ground speed, and angular steering velocity are considered in the generation of maneuvering paths. Based on the specifics of real field conditions (slope, plant residue, resistance due to soil compaction, etc.), the initial model was improved by introducing correction coefficients. An experimental setup is proposed using a tractor with two towed implements and a testing method involving point-to-point path comparison. The modeling method has potential for integrating more complex procedures (such as path generation, geolocation, and following) into the design of a maneuvering management system for agricultural machines, which can contribute to the efficiency of field operations. Keywords: Agricultural vehicle, Headland turn automation, Maneuverability, Modeling, Path generation, Path planning, Poly-articulated vehicle.

Correct energy management offers the best possibility for reducing the costs in agricultural production. In present day farming energy and agronomic efficiencies are both important factors. As the working-width of implements has increased, air-seeding is the best solution for the sowing of cereal crops. One of the problematic areas is the design of the air-delivery system, particularly if the pneumatic conveying system is wrongly dimensioned. The flow of seeding material during conveying must be high and regular enough for a high-speed seeding. There are three parameters that ensure the conveying of seeding material in a pipe: air velocity, flow concentration and pipe diameter. It is demonstrated that the outlets of the divider heads are the most critical part of the conveying system. Outlet pipes relatively small diameters and must allow for the highest seeding rates without clogging. It was hypothesised that the air velocity in outlet pipe may be used as an input data for designed a completed conveying system. This paper determines I) a minimal air velocity and flow concentration per type of seeds relative to pipe diameter; II) establishes a method to measure the air velocity of the loaded flow, which could be used to optimise existing seeders from an energy point of view; III) describes a global design methodology for air seeder conveying systems; IV) reports an comparative study of energy of the most commonly used outlet pipe diameters within the air-seeders; V) describes a method for calculating the energy consumption evaluation; VI) prescribes the optimum outlet pipe diameter deduced from our experimental results, necessary for the design of the following divider heads. Tests were carried out using for wheat and barley seeds, starter fertilisers and a wheat fertiliser mixture, for three currently used pipe diameters (20, 25 and 30 mm). (C) 2017 IAgrE. Published by Elsevier Ltd. All rights reserved.

As the working width of sowing implements increases, the use of conventional mechanical seed drills, with hoppers above all the implement working width, has reachedits limits. Any further increase of the working width (more than 4-6 m) or the coupling of conventional additional apparatus is expensive, complex and time-consuming. Air-seeding appears thus as the best solution to solve this problem. One storage hopper is able to supply the working width of 24 m or more. However, it should be noticed that to ensure uniform crop growing, a machine needs an accurate, technical solution to ensure seeding material to be distributed across the full implement working width. Indeed, low transversal distribution accuracy is one of the most important shortcomings of modem air-seeders. Even if air-seeding has been used for more than 50 years, few developments have been carried out on divider headers responsible for distribution accuracy.This paper deals with a study on the influence of divider head geometry and functioning conditions on the seed's distribution accuracy. The first part concerns the study of the influence of the air velocity and the material flow rate on the distribution accuracy. A second study deals with the influence of the outlet closing, of different outlet pipes lengths, of distribution head tightness, of the angle position of distribution heads. Finally the influence of the structural elements such as the pipe elbow, the tower configurations, the tower height and the cone shape deflectors' implementation on the divider lid is proposed. Moreover, observation of the seed's behaviour is undertaken using a high-speed camera system. These experimental results allowed for proposals of hypothesis about the parameters influencing the final result. This paper also proposes theoretical and mathematical explanations of the observed effects, necessary for future divider heads design. (C) 2017 IAgrE. Published by Elsevier Ltd. All rights reserved.

Modern seeding equipment must allow to cultivate sizeable areas efficiently and finalize the seeding in a short amount of time. Air-seeder is a solution for a fast seeding: seeds are conveyed from the high-capacity seed hopper to the coulter-bar by an air-stream. Taking into account the complexity of this type of seed drills, they stay little-studied. Few developments have been done on divider headers responsible of distribution accuracy. This paper deals with a study on the influence of divider head geometry and functioning conditions on the seed's distribution accuracy. Moreover, observation of the seed's behaviour is done using a high-speed camera system. These experimental results allowed proposals of hypothesis about the parameters influencing the final result, necessary for future divider heads design.

The air-seeder became a solution, when the working width increasing of conventional mechanical seed drills having the storage hopper across the all working width had reached its limits. The single storage hopper of a modern air-seeder can supply the working widths up to 24 m, over many operating hours. However, it should be noted that to ensure the accurate loading of metered material into the air delivery system, we are faced by the problem of pressure difference between the storage hopper and the air stream. Most modern air-seeders are equipped with a Venturi-injector or a pressurized hopper (called also: pressurized tank). Even if both loading systems are largely used, there are no theoretical and scientific justifications in favour of these systems, since few evaluation reports based only on practical observations are available. Thus, this paper deals with a study on the influence of an air-stream loading system type on the total energy consumption and seeds-metering precision. Moreover, this paper proposes an explanatory model of the functioning conditions of each system. Experimental demonstrations show that pressurized systems are more convenient from an energetic efficiency point of view.