A Variable Rate, Direct Nozzle Injection Field Sprayer

Rockwell, A. D.; Ayers, Paul D.

doi:10.13031/2013.25680

Cited by 33 publications

(21 citation statements)

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“…The response time includes delays between when the control signal was conveyed and when the application rate was actually attained (Fulton et al, 2005a). Rockwell and Ayers (1996) designed and constructed a variable-rate direct nozzle injection field sprayer and concluded that the system took 3.8 s to go from 10% to 90% of the step input. The reaction time for the control system in response to the differential global positioning system (DGPS) receiver can be as high as 2.2 s while maintaining a horizontal accuracy of 1 m (Al-Gaadi and Ayers, 1999).…”

mentioning

confidence: 99%

Real-Time Pressure and Flow Dynamics Due to Boom Section and Individual Nozzle Control on Agricultural Sprayers

Sharda¹,

Fulton²,

McDonald³

et al. 2010

Transactions of the ASABE

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Most modern spray controllers when coupled with a differential global positioning system (DGPS) receiver can provide automatic section or swath (boom section or nozzle) control capabilities that minimize overlap and application into undesirable areas. This technology can improve application accuracy of pesticides and fertilizers, thereby reducing the number of inputs while promoting environmental stewardship. However, dynamic system response for sprayer boom operation, which includes cycling or using auto-swath technology, has not been investigated. Therefore, a study was conducted to develop a methodology and subsequently perform experiments to evaluate tip pressure and system flow variations on a typical agricultural sprayer equipped with a controller that provided both boom section and nozzle control. To quantify flow dynamics during boom section or nozzle control, a testing protocol was established that included three simulation patterns under both flow compensation and no-compensation modes achieved via the spray controller. Overall system flow rate and nozzle tip pressure at ten boom locations were recorded and analyzed to quantify pressure and flow variations. Results indicated that the test methodology generated sufficient data to analyze nozzle tip pressure and system flow rate changes. The tip pressure for the compensated section control tests varied between 6.7% and 20.0%, which equated to an increase of 3.7% to 10.6% in tip flow rate. The pressure stabilization time when turning boom sections and nozzles off approached 25.2 s but only approached 15.6 s when turning them back on for the flow compensation tests. Although extended periods were required for the tip pressure to stabilize, the system flow rate typically stabilized in less than 7 s. The tip flow rate was consistently higher (up to 10.6%) than the target flow rate, indicating that system flow did not truly represent tip flow during section control. The no-compensation tests exhibited tip pressure increases up to 35.7% during boom and nozzle control, which equated to an 18.2% increase in tip flow. Therefore, flow compensation over no-compensation had better control of tip flow rate. A consistent difference existed in dynamic pressure response between boom section and nozzle control. Increased tip pressure and delayed pressure stabilization times indicated that application variability can occur when manually turning sections on and off or implementing auto-swath technology, but further testing is needed to better understand the effect on application accuracy of agricultural sprayers.

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confidence: 99%

Real-Time Pressure and Flow Dynamics Due to Boom Section and Individual Nozzle Control on Agricultural Sprayers

Sharda¹,

Fulton²,

McDonald³

et al. 2010

Transactions of the ASABE

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“…At 0.07 Hz, response lag times ranged from 0.250 to 0.377 s. When considering the previously mentioned lag time errors, these results are more than acceptable, as lag times were less than 1.0 s. These results also show the potential for misrepresenting results of an analysis focused solely on evaluating lag time. As demonstrated by past studies (Sudduth et al, 1995;Rockwell and Ayers, 1996;Vondricka and Schulze Lammers, 2009), nozzle response lag times are often reported, while the cumulative error with the delay in achieving an acceptable application rate is rarely stated. The results in table 4 show that while the lag times may be considered acceptable, the error magnitude may not.…”

Section: Ramp Response Analysismentioning

confidence: 99%

Control System Development and Response Analysis of an Electronically Actuated Variable-Orifice Nozzle for Agricultural Pesticide Applications

2015

Trans. ASABE

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“…The lateral resolution is determined by the spraying width while the longitudinal resolution is a function of both the spraying system response time and machine forward speed. The importance of delay time in the accuracy of machine application has been highlighted in many studies (Anderson and Humburg, 1997;Cahn and Hummel, 1995;Qiu et al, 1998;Rockwell and Ayers, 1996;Schueller and Wang, 1994;Sudduth et al, 1995;Tyler et al, 1997;Zhu et al, 1998).…”

Section: Variable Rate Application Errormentioning

confidence: 99%

Error Sources Affecting Variable Rate Application of Nitrogen Fertilizer

et al. 2004

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The accuracy and interaction among global positioning system (GPS) horizontal accuracy, differential GPS (DGPS) sampling frequencies and machine delay times of a hypothetical variable rate applicator for nitrogen (N) fertilizer application based on an application map in Florida citrus were studied. Parameters studied included: five GPS horizontal accuracy levels, two levels of DGPS horizontal accuracy, two DGPS sampling frequencies and two machine delay times. Two integrated models were developed which documented the effects of the parameters. Machine delay time was the most important factor and GPS horizontal accuracy was the second most important.

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A Variable Rate, Direct Nozzle Injection Field Sprayer

Cited by 33 publications

References 0 publications

Real-Time Pressure and Flow Dynamics Due to Boom Section and Individual Nozzle Control on Agricultural Sprayers

Real-Time Pressure and Flow Dynamics Due to Boom Section and Individual Nozzle Control on Agricultural Sprayers

Control System Development and Response Analysis of an Electronically Actuated Variable-Orifice Nozzle for Agricultural Pesticide Applications

Error Sources Affecting Variable Rate Application of Nitrogen Fertilizer

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