Elsevier

Biosystems Engineering

Volume 96, Issue 2, February 2007, Pages 161-168
Biosystems Engineering

Test Method for Boom Suspension Influence on Spray Distribution, Part II: Validation and Use of a Spray Distribution Model

https://doi.org/10.1016/j.biosystemseng.2006.10.003Get rights and content

In the first part of this paper, an experimental study of the influence of boom movements on ground distribution showed that a geometric static model should correctly be used for simulations. Such model was developed in Cemagref. The objective of this second part is to validate the results of this model for several kinds of excitation in laboratory and field conditions: laboratory validation used a conveyor and a shaking platform to reproduce pure vertical and horizontal movements; field validation was assessed on both concrete and field tracks to analyse combined movements. Then the model was used to define an evaluation method for sprayer boom behaviour at farm level. The concept is for the sprayer to travel over a bump, to measure boom movements and to simulate the distributions. The evenness is assessed through the coefficient of variation (CV) and the percentage of area correctly sprayed.

Introduction

This study was part of a European project (SPECS, 1998) to develop a boom test method at the farm level. This method should allow to test the performance of sprayers in use relatively to the uniformity of the ground distribution and to give advice for rapid corrections. Processing speed, easiness of use, accuracy and cost considerations were the key points of this project.

In the first part of this article (Lardoux et al., 2007), an experimental approach was described for the analysis of the importance of the main movements on the distribution. Roll and yaw movements were shown to have important effects on unevenness and it was concluded that, when these movements are uncoupled, a geometric representation should be able to predict ground distributions with sufficient accuracy. If such conclusion could be enlarged to the combined movements of the boom, an efficient test method could then follow the following steps: apply appropriate mechanical excitation on the sprayer, measure boom displacements and model ground distribution. With a model of low complexity (i.e. with no necessity of heavy means of computation and with a friendly interface), such protocol should allow results to be obtained quickly when an experimental approach based on distributions measurements would be very much longer to setup and less reproducible.

The main objective of this work was then to check the ability of a low complexity model, based on a geometric representation of the sprays, to predict distributions for uncoupled and for combined movements of the boom. Then, appropriate mechanical excitations to test the sprayers were discussed and a test method was designed both for the excitation and for boom measurements at the farm level. Finally, the ability of the combine use of these methods (mechanical excitation, boom measurement and simulation) to estimate the behaviour of the booms at the farm level was assessed.

Section snippets

Distribution model

To compute distribution on soil knowing boom movements, a geometric approach can be proposed as in De Baerdemaker et al. (1983), Chaplin and Wu (1989), Ramon and De Baerdemaeker (1996), Pochi and Vanucci (2002) and Lebeau (2003). Such a model was also developed in the Cemagref institute (the French Institute for Agricultural and Environmental Engineering Research) by Sinfort et al. (1994). This model can predict spray distributions under a moving boom in a two-dimensions. The simulation

Yaw movement

Grey level representations of the experimental and modelled distributions are shown in Fig. 3 in association with the boom rotation angle, for the test at 0·77 Hz and 6 km/h. Forward direction is from the top to the bottom of the figure. These distributions look similar: the model correctly predicts the areas over-sprayed, when the boom velocity decreases.

Results of analysis are given in Table 1. As expected, mean doses are under-evaluated for experimental results but they remain constant for all

Definition of a field sprayer test

The simulations give worse results than measurements, but this can be explained by the imperfections in the step calibration of the measurement method and in the reproductions of the movements with the track simulator. Taking into account the good results of the model for the laboratory tests, the model was assessed to correctly reproduce the evenness of the distributions and to predict the behaviour differences of the sprayers. It was then necessary to find a way to shake the sprayers and to

Conclusion

The results show that the model gives very good predictions for laboratory tests with pure vertical and horizontal movements. For combined movements, modelled and measured distributions have the same features but the same differences are always observed: lower doses, lower values for the coefficient of variation and higher surfaces with correct spraying for measurement distributions. Three combined factors are mainly responsible: the calibration step of the measurement method for the

Acknowledgements

Thanks are due to the other partners involved in the SPECS project: ‘European system for field sprayer inspection at the farm level’—Contract EEC CT 921170: Katholic University of Leuven (Belgium), Biologische Bundesanstalt für Land und Fortwirtschaft (Germany), Swedish University of Agricultural Sciences (Sweden), Istituto Sperimentale per la Meccanizzazione Agricola (Italy), Landesanstalt für Pfanzenschuts (Germany), Cemagref (France). This was supported by the Cemagref team of the

References (16)

  • H. Ramon et al.

    Spray boom motions and spray distribution: Part 1, derivation of a mathematical relation

    Journal of Agricultural Engineering Research

    (1997)
  • J. Chaplin et al.

    Dynamic modelling of field sprayers

    Transactions of the ASAE

    (1989)
  • De Baerdemaeker J S; Jaques M; Verdonck E (1983). Modelling the dynamic behaviour of sprayers booms. ASAE Paper No....
  • P. Enfält et al.

    Assessment of the dynamic spray distribution on a flat surface using image analysis. Optimising pesticide applications.

    Aspects of Applied Biology

    (1997)
  • ISO 5682/1 (1981). Equipment for crop protection—spraying equipment—part 1: test methods of sprayer nozzles....
  • J.J. Langenakens et al.

    A model for measuring the effect of tire pressure and driving speed on horizontal sprayer boom movements and spray pattern

    Transactions of the ASAE

    (1995)
  • Lardoux Y; Sinfort C; Enfält P; Sevila F (2006). Test method for boom suspension influence on spray distribution, part...
  • Lebeau F (2003). Modélisation de la répartition dynamique au sol des produits phytosanitaires sous une rampe de...
There are more references available in the full text version of this article.

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