THE EFFECT OF TYRE PRESSURE AND DRIVING SPEED ON THE DYNAMIC BEHAVIOUR OF SPRAYER BOOMS AND THE SPRAY DISTRIBUTION

摘要

Chemical products for crop protection are normally distributed as liquids using sprayers equipped with a sprayer boom of which the width varies between 9 and 36 metres. The spraying liquid must be distributed regularly to obtain a uniform spray pattern. Underdoses result in incomplete crop protection so that surviving weeds, insects and pests can still cause damage. Overdoses are uneconomical, damage cultivated crops and increase pollution pressure on the environment. Horizontal boom movements, effected by soil unevenness cause an irregular spray pattern in the driving direction. A modal model is developed, based on experimental measurements and modal analysis techniques. Field input forces are simulated with a tractor model driven over a standardised bumpy road. The modal model and the input force are combined in a forced response technique to simulate the boom movements by which the spray deposit distribution is computed. A comparison of these spray patterns for different tyre pressures and driving speeds gives an optimal range of use for the tested sprayer, tractor and tyres. This method allows rapid testing of new sprayer designs.