Optimisation of mechanical weeding in row crops by cross row hoeing
rotary hoe, mechanical weed control, virtual prototype
The need for non-chemical weed control techniques has steadily increased in the last fifteen years, as a consequence of the environmental pollution originated by intensive application of pesticides in agriculture. Another reason why non-chemical weeding is in the limelight nowadays is increased interest for organically produced agricultural products and foodstuffs. In EU-Regulation 2092/91 it is expressly stated that only non-chemical weed control can be used in organic farming. In row crops approximately 80 % of a field could be covered by conventional methods for inter-row weed control. Unfortunately, the weeds occur in the remaining area between (intra-row) and around the crop plants (close-to-crop) have a much bigger impact on the plant development and yield. However, mechanisation of intra-row area cultivation is a complex task and because of that, hand weeding is still the most frequently used method of intra-row weed control. Concerning non-chemical weed control demands, research on new techniques for physical weed control and development of self-propelled weeding robots is particularly emphasised. Main objective of this research is development of an optimal weeding tool for mechanical weed control of the intra-row area in row crops, which could be adapted to different crop species, different plant intra-row distances and plant growth stages. The path from idea to the first prototype was significantly shortened by use of integrated mechanism design and simulations. Considering demands and constrains, a virtual prototype of the rotary hoe for intra-row weed control was designed. The hoeing tool consists of an arm holder and three or more integrated arms rotating around a horizontal axis above the crop row. The axis is attached to the motor shaft which rotational speed is calculated and tuned according to the forward speed of the carrier vehicle, intra-row distance between plants and observed position of the arms. Kinematical behaviour of the hoes virtual prototype was simulated in order to optimise the hoeing process and trajectories of duckfoots under the soil surface in the intra-row area. After the comprehensive analysis of results observed with the virtual prototype the first physical prototype is built. Experimental tests and optimisation of the real-time control of the system are underway.
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