This disclosure relates generally to the control and design of liquid or granular spraying systems based on the spray pattern in a target area, field or ground.
In the agricultural industry, sprayers provide liquid nutrients, fertilizer, herbicides, and water to plants, crops, trees, and other vegetation. Sometimes too much liquid is sprayed and the crops may grow poorly or even drown from root rot. If there is insufficient spraying, the crops may not mature, the yield is lower, and money, time and resources are again wasted. Also, if a chemical may have harmful consequences, then over-spraying may create more harm, plus money is wasted in paying for extra chemicals. Other variables include vehicle speed, wind and spray drift effects that may cause the spray to drift past the boundaries of the field and land on neighboring crops or houses.
Nozzles may be either continuous spray or pulse mode spray so that the spray pattern on the ground may not be the same, but both modes of spraying can generate uneven spray patterns on the ground. The controller system for the fluid may release the fluid continuously or send periodic signals such as a pulse-width modulated (PWM) signal to release the fluid. In many settings, not just a single but multiple nozzles are used together. Sprayer systems have multiple nozzle bodies or outlets to apply liquids over a large or intricate surface area. Sometimes the activity of more than one hundred nozzles is coordinated, which makes PWM control complex.
Instead of liquids being sprayed, granular solid fertilizer or other chemicals may also be sprayed (broadcasted) out of long nozzle tubes onto the ground. The wind or vehicle travel speed may be such that finer grains of solid fertilizer or other chemicals would swirl and drift and may behave similarly to liquid droplets.
Some embodiments include a system configured to disperse fluids or fine granular particles from an agricultural vehicle. The system includes a sprayer configured to dispense the fluids or fine granular particles; and a controller cooperative with a plurality of sensors to sense vehicle travel speed, vehicle travel direction, wind speed, wind direction, a height of a first nozzle from a ground surface, and a height of a second nozzle from the ground surface. The controller includes a memory storing a look-up table having fan angles of the first and second nozzles, and a processor configured to compute a first spray pattern on the ground surface based on the fluid dispensed through the first nozzle. The processor is also configured to compute a second spray pattern on the ground surface based on the fluid dispensed through the second nozzle, and to determine an overlap region between the first spray pattern and the second spray pattern. The processor is configured to compare the determined overlap region with a pre-determined overlap, and take corrective action automatically by performing at least one of the following actions: changing travel speed of the vehicle and changing a duration of time the fluids or fine granular particles are dispensed from the first and second nozzles.
Some embodiments include a method of dispersing fluids or fine granular particles from an agricultural vehicle. The method includes dispensing the fluids or fine granular particles through a first nozzle and a second nozzle, and sensing at least one of vehicle travel speed, vehicle travel direction, wind speed, wind direction, a first height of the first nozzle from a ground surface, and a second height of the second nozzle from the ground surface. The method further includes computing, with a processor, a first spray pattern on the ground surface based on the fluids or fine granular particles dispensed through the first nozzle, and computing, with the processor, a second spray pattern on the ground surface based on the fluids or fine granular particles dispensed through the second nozzle. The method further includes determining, with the processor, an overlap region between the first spray pattern and the second spray pattern, comparing, with a processor, the determined overlap region with a pre-determined overlap, and taking corrective action automatically by performing at least one of the following actions with the processor: changing the vehicle travel speed and changing a duration of time the fluids or fine granular particles are dispensed from at least one of the first nozzle and the second nozzle.
Some embodiments include a system configured to disperse fluids or fine granular particles in a field from an agricultural vehicle. The system includes a sprayer configured to dispense the fluids or fine granular particles, and a controller cooperative with a plurality of sensors to sense vehicle travel speed, vehicle travel direction, wind speed, wind direction, a height of a first nozzle from a ground surface, and a height of a second nozzle from the ground surface. The controller includes a memory storing a look-up table having fan angles of the first and second nozzles. The controller further includes a processor configured to compute a first spray pattern on the ground surface based on the fluid dispensed through the first nozzle during a first pass through the field, compute a second spray pattern on the ground surface based on the fluid dispensed through the second nozzle during the first pass through the field, and determine a first overlap region between the first spray pattern and the second spray pattern. The controller is configured to compare the first overlap region with a pre-determined overlap and take corrective action automatically by performing at least one of the following actions: changing travel speed of the vehicle and changing a duration of time the fluids or fine granular particles are dispensed from the nozzle. The controller is further configured to compute a third spray pattern on the ground surface based on the fluid dispensed through the first nozzle during a second pass through the field, the second pass adjacent to the first pass, compute a fourth spray pattern on the ground surface based on the fluid dispensed through the second nozzle during the second pass through the field, determine a second overlap region between the third spray pattern and the fourth spray pattern, and compare the second overlap region with a pre-determined overlap. The controller is further configured to determine a third overlap region between the first and second spray patterns and the third and fourth spray patterns, compare the third overlap region with a pre-determined overlap, and take corrective action automatically by performing at least one of the following actions: changing travel speed of the vehicle and changing a duration of time the fluids or fine granular particles are dispensed from the nozzle.
Various aspects of example embodiments are set out below and in the claims. Embodiments include a sprayer system having dynamic monitoring or prediction of the spray pattern on the ground (or target area) such as the overlap or drift of spray patterns produced during operation of an agricultural vehicle in a crop field. The predicted or monitored pattern on the ground is compared with a desired pattern in a desired grid. If the desired ground pattern is not occurring, then corrective or counter-balancing action is taken. For example, when there are multiple sprayers, adjacent or near neighboring nozzle bodies and their spray overlap patterns are determined together. As the sprayer moves forward, the overlap of the ground patterns is determined in the direction of travel. These overlap calculations are corrected based on the type of nozzle heads used, the type of spray (continuous or pulsed), travel speed, external conditions, and so on. Adaptive action is taken to optimize uniformity of spray, location of spray or drift and so on. Other operation modes, features and embodiments are disclosed in the detailed description, accompanying drawings and claims.
The detailed description refers to the following example figures.
Disclosed embodiments focus on determining whether fluid spray or fine granular particles land in a desired region behind an agricultural vehicle (e.g. self-propelled sprayer, tractor or dry spreader). The determination is based on either a spray detector mounted behind the spray boom, or on a predictive model based on spray model (e.g. AGDISP plume model or spray drift model), or on a predictive trigonometric model. The computational processing circuits are mounted on a controller mounted on the spray boom or center frame behind the sprayer vehicle. For the predictive models such as AGDISP, a lookup table and a small amount of dynamic computation are used to predict where the spray is landing on the ground. Variables such as the spray nozzle properties (e.g. type of nozzle, nozzle tip, spray cone, fan angle), the atmospheric conditions (wind, air pressure, humidity, temperature, etc.), vehicle speed/direction, terrain (hills and angle), spray pressure, fluid flow rate and other conditions are used to feed into the lookup table and geometric calculation (e.g. height of spray boom or height of the nozzles, length of the boom, dip angle of the boom) to determine the amount and location of the spray on the ground. A lower fluid pressure and/or higher flow rate results in coarser droplets, whereas higher fluid pressure and/or lower flow rate results in finer droplets. Typically, smaller droplets are more prone to drift.
Alternatively, when the spray droplet size or the size of the granular particles are above a certain size to more or less ensure ideal spray/spread conditions, the predictive trigonometric model, a small lookup table and dynamic computation are used to predict where the spray is approximately landing on the ground. The spray nozzle properties (e.g. type of nozzle, nozzle tip, spray cone, fan angle), geometry (e.g. height of the boom or nozzles), speed/direction of the vehicle, location of the vehicle (e.g. GPS, RTK), and wind speed/direction are considered in the calculation. For instance a spray cone and ground spray spot is determined; the angle from vertical of the central vertical axis of the cone is adjusted based on the vehicle travel speed/direction and the wind speed/direction. With either predictive calculation model (e.g. AGDSIP or trigonometric), the spray from every single nozzle is computed in order to predict side to side fluid spray overlap/skips or to predict forward-aft overlap/skips. If only the spray drift past a safe or buffer zone is desired, then assessment of the corner (far ends of the boom) spray is generally sufficient (e.g. spray from the last boom section or last few nozzles). The location of the vehicle is compared with the location of the buffer zone or of the boundary of the farm field to check whether the spray is drifting past desired grid area. When the spray goes past the buffer zone, the relevant nozzles may be turned off or the pointing direction of the spray nozzles is adjusted, or the height of the boom is lowered, etc. The buffer zone can be defined by boundaries having any suitable shape based upon the geometry of the field and any obstacles or no-spray zones.
The predictive ground spray calculations or detected spray on the ground from each nozzle can be aggregated to determine an actual spray area occurring on the ground from the nozzles, collectively. By taking into account of all the spray from each nozzle, then it is possible to calculate the amount of spray overlap either side to side or spray overlap in the fore-aft direction in the back of the direction of travel (behind the vehicle). When the overlap exceeds a certain amount indicating that the spray pattern is not uniform, the sprayer system takes correction action. For example, the PWM frequency is increased or the sprayer is slowed down, pointing direction of the nozzles, the nozzle angle, boom angle, and/or boom height, etc., is adjusted.
The spray actually occurring on the ground is detected by a combination of sensors and visual indicators (e.g. camera image). Alternatively, the plume models or spray drift models are used. Such models, e.g. AGDISP, are described in various university publications or in research literature from the USDA. By contrast,
The following are example actions to counter-balance fluid release that is not yielding a desired ground spray pattern or not occurring in a desired spray cone or desired spray grid. For instance,
In some embodiments, different spray nozzle tips can be utilized along a length of the boom. For example, each of the spray nozzles is controlled automatically by a processor and therefore, each of the spray nozzles can use the same or different tip as an adjacent nozzle. The processor is capable of configuring each of the individual nozzles to spray over the desired area.
In the embodiments of
Determining the overlap of spray from the nozzles or spreader nozzle heads can be more complex. For adjacent situations, the overlap is calculated in order to decide whether to increase spray pressure, switch nozzle tips, turn on/off nozzle tips, and/or change the pointing direction of the spray nozzle and so on. For forward-aft situations in the direction of travel, with pulsed spraying, skips in the spray pattern are reduced by proper consideration of overlaps; i.e. if overlap is zero and the patterns are far apart, then skipping has occurred and the vehicle should slow down or the pulse frequency or pulse width should increase. The example embodiments include electronically wired or wirelessly controlled sprayer systems. Not only PWM controlled spray nozzles release fluid that may generate uneven spray patterns on the ground, but continuously spraying nozzles can also do the same. For example, as the fluid pressure or terrain changes or the wind direction shifts or there is higher speed wind or less wind, the released fluids from the continuously spraying nozzles will also shift direction so that the spray pattern on the ground is patchy, uneven or not uniform.
In some versions of the system, overlap calculation is performed when taking into consideration spray drift or vehicle operation modes (e.g. turning or changing lanes). In addition, border problems, spraying past a boundary can also be addressed by the methods described herein.
When the spray overlap occurring on the ground is more than a desired amount (e.g. more than 5% overlap of the ground patterns), lowering the height of the boom is another alternative embodiment. Alternatively, every other nozzle body or every other nozzle tip on a nozzle body may be turned off. Another alternative is to adjust the pressure of the fluid.
When there is hilly ground, the overlap calculation includes a “hill” effect due because there is a height variable that accounts for the height differences of the nozzle tips to the surface of the ground directly below each nozzle tip. When the spray overlap occurring on the ground is more than a desired amount (e.g. more than 5% overlap of the ground patterns), some of the aforementioned methods are used (e.g. lower boom height). Alternatively, the pointing direction of a nozzle body is adjusted. The pointing direction is then included in a subsequent calculation of the spray pattern occurring on the ground.
Key Parameters, and Whether Skipping has Occurred:
One useful consideration is that a horizontal slice of a cone preserves the fan angle for either an up-right cone or a leaning cone. All of the fan angles for each nozzle type can be stored into the computer memory so that the value may be recalled once a nozzle type is keyed into the system.
There are two parameters of a cone that determine the spray area occurring on the ground: the height of the cone (or distance h from the nozzle tip to the ground), which is readily known based off of the boom height on a sprayer and a fan angle φ. A particular type of nozzle tip generates a particular pattern such as a cone, which is characterized by its fan angle φ (see
Radius R=h×tan(φ)
This radius R is useful when calculating distances in one dimension so as to compare it with the distance of travel within a time T. Speed=Distance/Time may be used to compute a linear value whether the Distance traveled is greater than the size of R. If Distance is greater than R, skipping occurred. Corrective action includes slowing down the vehicle or spraying longer duration (ON mode is longer) or spraying faster.
To take into account the wind or vehicle travel speed (relative wind), the area on the ground is calculated by transforming the coordinates from the stationary frame (as if the spray were occurring when there is no wind and the vehicle is stopped) to the moving frame. For example, a circle on the ground becomes elongated like an ellipse after the coordinate transformation.
Pulsed Spraying, Circular Spray Pattern, Over or Under Spraying, or Uniform Spraying:
This is a straightforward situation that may occur when the wind and direction of travel of the spray vehicle cancels each other and the nozzle operates in pulse mode. A nozzle spray tip ejects a conical spray during the ON state (e.g. ON mode) of the pulse and the spray pattern is ejected out for the duration of the ON state and the vehicle has not traveled much during the ON state.
With reference to
Pulsed Spraying, Two Different Nozzle Tips Side by Side Spray Pattern:
This is still somewhat straightforward situation that may occur when the wind and direction of travel of the spray vehicle cancels each other and the nozzle operates in pulse mode. The adjacent nozzle tips have different orifices or openings. Each nozzle spray tip ejects a conical spray during the ON state (e.g. ON mode) of the pulse and the spray pattern is ejected out for the duration of the ON state and the vehicle has not traveled much during the ON state.
The side-to-side overlap is given by (see http://mathworld.wolfram.com/Circle-CircleIntersection.html) and
Pulsed Spraying, Ellipse Spray Pattern:
Ellipse spray patterns on the ground are more likely in reality. For example, the sprayer is traveling at 20 mph, which is effectively a 20 mile wind as seen by the spray droplets. So the cone is distorted or leaning and the planar slice of the cone parallel to the ground is approximately elliptical or a stretched circle. One embodiment of the calculation is to transform the coordinates from a vertical symmetric cone to a leaning cone and vice versa. An alternative embodiment is the slice the vertical symmetric cone at an angle so that the planar surface (representing the spray spot on the ground) of the slice is at an angle and/or tilt with respect to the surface of the ground or earth surface. There is a mathematical equation relationship between this slice angle and the wind or vehicle velocity (speed and direction). Yet another example alternative method to account for the aggregated wind/vehicle velocity on the spray drift is pictorially shown in
Continuous Spraying, Circular Spray Pattern:
This is akin to a spray paint situation. It includes a question whether there has been a uniform amount of spraying performed if the spray pattern is circular on the ground. To reach an optimal solution as to the travel speed and the amount of fluid dispensed, one solution is to store and use the algorithm described in “CAD-based Automated Robot Trajectory Planning for Spray Painting of Free-form Surfaces,” Heping Chen, et al., Industrial Robot: An Int'l Journal Vol. 29, No. 5, pp. 426-433 (2002).
Continuous Spraying, Ellipse Spray Pattern:
A determination is made of whether there has been a uniform amount of spraying performed if the spray pattern is elliptical on the ground. To reach an optimal solution as to the travel speed and the amount of fluid dispensed, one solution is to store and use the algorithm described in “Calculating Ellipse Overlap Areas,” Gary Hughes and Mohcine Chraibi (2013). Although this article provides many complicated scenarios, the two point intersection solution tends to be most applicable to the agricultural situation since the spray release is fairly constant. The wind and weather condition is also fairly constant during each hour of operation.
Boundary Problems:
This includes a one-dimensional problem, side to side, method of avoiding spraying outside the boundary. GPS, stored maps, local coordinate grid provides where the boundary of the field is. Then as for the spray pattern, it does not matter whether there is a circle or an ellipse spray pattern. Taking the “radius” R as the length of the spray pattern perpendicular to the height h, the radius of the circle or the ellipse on the ground, at distance h from the nozzle tip is given by:
Radius R=h×tan(φ)
This radius R is useful when calculating distances in one dimension so as to compare it with the distance of travel within a time T. Speed=Distance/Time may be used to compute a linear value whether the distance traveled is greater than the size of R. If the distance is greater than R, skipping occurred. Corrective action includes slowing down the vehicle or spraying longer duration (ON mode is longer) or spraying faster.
The radius R of the spray is longer or shorter depending on the wind direction relative to the direction of spray and travel. If the wind is parallel or anti-parallel to the direction of travel, radius R is its usual full length since the wind is perpendicular to R.
Rectangular Spray Pattern, New Nozzle Tips:
A toothbrush stipple pattern at the nozzle tip or rectangular spray nozzle opening is used to generate spray patterns on the ground from each nozzle that are more rectangular than elliptical. This simplifies the calculations since the overlap of rectangular areas can be determined from the four corners of the rectangle. The geometric/trigonometric equations are also simpler than ellipses and even when there is wind or vehicle velocity, the spray pattern occurring on the ground tends to remain a rectangular shape so that overlap from different nozzle sprays or spray past a desired area is readily computed. Alternatively, other nozzles tips (e.g. long elliptical patterns) generate a ground pattern that is closely approximated by a rectangular spray area on the ground so that the computation for such nozzles is simplified.
In some embodiments, an air-assist system is used at the nozzle spray tips to speed up the droplets to thereby reduce the amount of drift. The air-assist system is used to increase the pressure of the fluid exiting the nozzle spray tips.
Another example method of determining the adjusted fan angle in
In yet another computational embodiment, the plume models or spray drift models are substituted for the trigonometric calculations described above. Such models, e.g. AGDISP, are described in various university publications or in research literature from the USDA. When combined with lookup tables, the resulting spray occurring on the ground is predicted for each individual nozzle or the nozzles on the ends and/or center of the spray boom. Then again the aggregated effect of all the nozzles is calculated and the spray areas are compared with the desired spray region. If the difference is greater than some acceptable amount (e.g. 10% or a regulation amount), then corrective actions can be taken either automatically or manually by the vehicle operator. When corrective action is taken automatically, no operator input or intervention is required to execute the corrective action. Corrective actions such as those mentioned above or depicted in the figures may be utilized.
Although much of this disclosure focuses on spray overlap among the nozzles themselves, instead of checking for overlap between the spray areas among adjacent or traveling nozzles, it is also possible to check whether the spray areas on the ground overlap with the buffer zone area or the boundary of the farm. If the ground spray area touches or extends into the buffer zone, an alert is generated by the computer to signify that there may be a problematic spray drift situation; the degree of overlap can generate different types or degrees of alarms. The graphical view (e.g.
Instead of mathematically predicting or calculating the spray pattern on the ground past the buffer zone area, a physical detection system may be used. For a rectangular spray region, the four corners of the spray regions due to the outer spray nozzle bodies can be used to determine whether spray is occurring within a desired area. For example, the outermost spray nozzles release a special detectable fluid such as fluorescent liquid or dyed liquid or some fluid that is different from the primary fluids (e.g. fertilizer) being released. The spray nozzles located on the ends of the boom breakaway wings or even the outermost boom section can release the tagged fluid. Machine vision, camera or sensors detect the back scatter or reflected light or other signals to analyze the electromagnetic or color or content spectrum of the detected signals from the tagged fluid that has traveled to the ground. As the vehicle travels, the detected signals indicate or can be used to arithmetically map out a path line for the spray fluid that has already hit the ground (e.g. “connect the dots”). When the path line crosses the boundary into the buffer zone area or territory of the farm, then the spray may be considered to have drifted into an undesirable area. Various corrective or notification indicators may occur, such as an alarm, computer alert, some spray nozzles are turned off, the fluid pressure is reduced, the boom height is lowered, and so on. Such indicators may be gradated depending on how far into the undesirable region the spray has drifted past.
In some embodiments, the processor can store and reference the data from previous passes through a field and adjust the flow rate and other factors accordingly. For example, if on a first pass across the field, drift occurs into the area that will be covered by a second pass across the field, the processor can reduce the flow or turn off some of the nozzles adjacent the first pass when the vehicle makes the second pass to avoid over-treating any portion of the field.
Finally, the orientation and directions stated and illustrated in this disclosure should not be taken as limiting. Many of the orientations stated in this disclosure and claims are with reference to the direction of travel of the equipment. But, the directions, e.g. “behind” can also be merely illustrative and do not orient the embodiments absolutely in space. That is, a structure manufactured on its “side” or “bottom” is merely an arbitrary orientation in space that has no absolute direction. Also, in actual usage, for example, the nozzles and boom equipment may be operated or positioned at an angle because the implements may move in many directions on a hill; and then, “top” is pointing to the “side.” Thus, the stated directions in this application may be arbitrary designations.
In the present disclosure, the descriptions and example embodiments should not be viewed as limiting. Rather, there are variations and modifications that may be made without departing from the scope of the appended claims. For example, although the region behind the spray vehicle was discussed in this disclosure, spray drifting towards the region ahead of the boom or vehicle would be addressed similarly.
This patent application claims priority to U.S. Provisional Patent Application Ser. No. 62/182,928, filed Jun. 22, 2015, and entitled, SPRAY PATTERN OF NOZZLE SYSTEMS, the contents of which are incorporated herein by reference. This patent application is related to U.S. patent application Ser. No. 14/506,057, filed Oct. 3, 2014, and entitled, HYBRID FLOW NOZZLE AND CONTROL SYSTEM, which claims priority to U.S. Provisional Patent Application Ser. No. 62/050,530, filed Sep. 15, 2014, and entitled, TIME VARYING CONTROL OF THE OPERATION OF SPRAY SYSTEMS, and to U.S. Provisional Patent Application Ser. No. 62/015,315, filed Jun. 20, 2014, and entitled, HYBRID FLOW NOZZLE AND CONTROL SYSTEM, the contents of all of which are incorporated herein by reference.
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