An automatic machine able to perform variable rate application of flame weeding: design and assembly

This paper describes the design and development of an automatic machine able to perform Variable Rate Application of cross flaming in maize fields. The VRA flaming machine was designed to remove weeds mechanically from the inter-row area and perform selective and targeted cross flaming along the crop rows. The mechanical treatment will be performed in a continuous way, even without weed presence. On the contrary, cross flaming on the maize rows is applied selective and automatically only if weeds are presence. Flame weeding is applied by means of prismatic burners fed by Liquefied Petroleum Gas, able to treat 25 cm wide strips of soil surface including crop rows. Flaming can be used selectively in maize, which can tolerate the heat released from the burners. Mechanism of morphological tolerance is the presence of many layers of the outer leaf tissue protecting the inner growing point. A low or a high LPG dose can be chosen automatically according to the weed cover percentage detected by a weed detection system. The ignition system of the VRA flaming machine is almost instantaneous and the complete flame in the burner is obtained in 0.4 s. The machine is provided with an automatic steering system in order to avoid damaging the maize plants with the rigid tools used for mechanical weed removal. The VRA flaming machine is a new technology for precision agriculture and was designed and built within the “Robot fleets for Highly Effective Agriculture and forestry management” (RHEA) Project, funded by EU, aimed to develop a fleet of heterogeneous autonomous robot units in order to perform site-specific treatments related to crop protection in different agricultural scenarios.