DIGITAL FLOW CONTROL FOR AUTOMATION OF PRECISION AGRICULTURAL SPRAYING

INACCURACY IN AGRICULTURAL CHEMICAL APPLICATION CAUSES INCREASED PRODUCTION COSTS AND RELEASES UNNECESSARY PESTICIDE AND FERTILIZERS INTO THE ENVIRONMENT. APPLICATION CONTROL IS PRIMARILY A MANUAL OPERATION AND ON-THE-GO ADJUSTMENT OF SPRAY OUTPUT FOR SPRAY TARGET OR TRAVEL SPEED VARIATION IS RARE. HOWEVER, COMMERCIALIZATION AND USE OF ELECTRONIC SYSTEMS FOR SPEED-BASED APPLICATION CONTROL IS INCREASING. TECHNOLOGY ADVANCES FOR LOCAL NAVIGATION AND ELECTRONIC SENSING OF SOIL AND PLANT CHARACTERISTICS ALLOW SPRAYER CONTROL TO BE BASED ON LOCALIZED TARGET REQUIREMENTS AND INSTANTANEOUS SPRAYER CONDITIONS. REGARDLESS OF THE CONTROL STRATEGY, THE SYSTEMS MUST ULTIMATELY ADJUST THE FLOW RATE OF SPRAY EMITTED FROM THE NOZZLES. PRESSURE VARIATION, THE CURRENT TECHNIQUE FOR FLOW CONTROL, CAUSES ADVERSE EFFECTS ON SPRAY PATTERNS AND DROPLET SIZE SPECTRA AND RESULTS IN NON UNIFORM SPRAY DEPOSITION. THIS PROJECT WILL INVESTIGATE A DIGITAL FLOW CONTROL TECHNIQUE USING PULSE WIDTH MODULATION OF FLOW THROUGH STANDARD SPRAY NOZZLES. UNIVERSITY RESEARCH HAS SHOWN THE TECHNIQUE TO ALLOW A WIDE RANGE OF FLOW CONTROL WITHOUT ADVERSE EFFECTS ON SPRAY BEHAVIOR. THE PROPOSED EFFORT WILL ESTABLISH PRACTICAL FEASIBILITY OF THE SYSTEM THROUGH DURABILITY AND FIELD PERFORMANCE TESTING. ADVANTAGES OF THE PROPOSED APPROACH OVER EXISTING FLOW CONTROL SYSTEMS WILL BE DOCUMENTED.