Patent Description:
Modern field irrigation machines are combinations of drive systems and sprinkler systems. Generally, these systems are divided into two types depending on the type of travel they are designed to execute: center pivot and/or linear.

Regardless of being center pivot or linear, common irrigation machines most often include an overhead sprinkler irrigation system consisting of several segments of pipe (usually galvanized steel or aluminum) joined together and supported by trusses, mounted on wheeled towers with sprinklers positioned along its length. These machines move in a circular pattern (if center pivot) or linearly and are fed with water from an outside source such as a well or water line. The essential function of an irrigation machine is to apply an applicant (i.e. water or other solution) to a given location.

The quantity or flowrate of water (or other applicant) supplied to an irrigation system may be limited or reduced below the optimal rate for the irrigation machine. This is often caused by issues such as: competing demands on a water supply; failure of a pump or well in a multi source plumbing network; seasonal changes in water depth; and a variety of other reasons. Further, the flow demand from the irrigation machine may increase above the flowrate of water available from the water source. This is often seen on corner irrigation machines when the corner is extended into the corners of the field.

Flow demands in excess of application rates cause water pressure to drop within the machine and within the plumbing network supplying the irrigation machine. This limits the operating effectiveness of the irrigation system, reducing the actual application rate below the commanded application rate. Further, this reduction below the commanded application rate increases with the distance from the pivot point, thus affecting the uniformity of water application along the length of the machine. In extreme cases it is possible that one or more sprinklers near the end of the machine may not apply any water. Accordingly, modern irrigation systems operate poorly at flow rates and pressures below their design values. This is an important limitation when lower flow rates cannot be avoided.

<CIT>, <CIT> and <CIT> provide examples of prior irrigation systems.

To address the shortcomings presented in the prior art, the present invention provides a system and method for maintaining a required minimum pressure level in an irrigation system receiving a reduced flow rate of applicant while also maintaining the target depth of an applicant. Aspects of the present invention are defined in the claims below.

The accompanying drawings, which are incorporated in and constitute part of the specification, illustrate various embodiments of the present invention and together with the description, serve to explain the principles of the present invention.

For the purposes of promoting an understanding of the principles of the present invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the present invention is hereby intended and such alterations and further modifications in the illustrated devices are contemplated as would normally occur to one skilled in the art.

The terms"program,""computer program,""software application,""module" and the like as used herein, are defined as a sequence of instructions designed for execution on a computer system. A program, computer program, module or software application may include a subroutine, a function, a procedure, an object implementation, an executable application, an applet, a servlet, a source code, an object code, a shared library, a dynamic load library and/or other sequence of instructions designed for execution on a computer system. A data storage means, as defined herein, includes many different types of computer readable media that allow a computer to read data therefrom and that maintain the data stored for the computer to be able to read the data again. Such data storage means can include, for example, non volatile memory, such as ROM, Flash memory, battery backed-up RAM, Disk drive memory, CD-ROM, DVD, and other permanent storage media. However, even volatile storage such a RAM, buffers, cache memory, and network circuits are contemplated to serve as such data storage means according to different embodiments of the present invention.

<FIG> illustrates an exemplary self-propelled irrigation system <NUM> which may be used with example implementations of the present invention. As should be understood, the irrigation system <NUM> disclosed in <FIG> is an exemplary irrigation system onto which the features of the present invention may be integrated. Accordingly, <FIG> is intended to be illustrative and any of a variety of systems (i.e. fixed systems as well as linear and center pivot self- propelled irrigation systems; corner systems) may be used with the present invention without limitation.

With reference now to <FIG>, an exemplary irrigation machine <NUM> of the present invention preferably may include a main span <NUM>, a center pivot structure <NUM> and supporting drive towers <NUM>, <NUM>. The exemplary irrigation machine <NUM> may also include a corner span <NUM> attached at a connection point <NUM>. The corner span <NUM> may be supported and moved by a steerable drive unit <NUM>. The corner span <NUM> may include a boom <NUM> and an end gun (not shown) and/or other sprayers. Additionally, a position sensor <NUM> may provide positional and angular orientation data for the system as discussed further below. Further, a central control panel <NUM> is provided for enclosing on-board computer elements such as elements of the exemplary control device <NUM> as discussed below. The control panel <NUM> may also be linked to a transceiver for transmitting and receiving data between system elements, device/internet clouds <NUM>, remote servers <NUM> and/or the like. In accordance with a further aspect of the present invention, the control panel <NUM> may be further linked to a remote sensing element such as a sensor suite located on an aerial vehicle <NUM> (UAV/MAV), satellite <NUM> and other high-altitude monitoring systems.

Additionally, the system may include and/or receive data from sensors providing in-situ soil data <NUM> (e.g. moisture content) and/or crop related data. The system may also include image sensors <NUM>, <NUM> which preferably may include sensors to indirectly determine the moisture levels in a given area of soil and/or optics to allow for the detection of crop type, stage of grown, health, presence of disease, rate of growth and the like. The system may also receive include a weather station <NUM> or the like to measure weather features such as humidity, pressure, precipitation, solar radiation, temperature and the like. Additionally, the system may include wireless transceivers/routers <NUM>, <NUM> for receiving and transmitting signals between system elements. Preferably, the data collected by the detectors and sensors of the present invention are forwarded to a main control panel <NUM> and control device <NUM> as discussed further below. Alternatively, the received data may be collected and retransmitted to a remote server/cloud for processing and analysis.

With reference now to <FIG>, an exemplary control device <NUM> which represents functionality to control one or more operational aspects of the irrigation system <NUM> will now be discussed. As shown, the exemplary control device <NUM> may preferably include a controller <NUM> which may include a data storage module <NUM> and an irrigation prescription module <NUM>. The irrigation prescription module <NUM> is preferably software code and embedded logic which controls the application of applicants by the system as discussed further below.

The controller <NUM> preferably provides processing functionality for the control device <NUM> and may include any number of processors, micro-controllers, or other processing systems. The controller <NUM> may execute one or more software programs/modules that implement techniques described herein. The memory/data storage module <NUM> is an example of tangible computer-readable media that provides storage functionality to store various data associated with the operation of the control device <NUM>, such as the software program and code segments mentioned above, or other data to instruct the controller <NUM> and other elements of the control device <NUM> to perform the steps described herein. The data storage module <NUM> may include, for example, removable and non- removable memory elements such as RAM, ROM, Flash (e.g., SD Card, mini-SD card, micro-SD Card), magnetic, optical, USB memory devices, and so forth.

In implementations, the exemplary control device <NUM> preferably further includes a power control system <NUM> and a power-line BUS <NUM> which may include conductive transmission lines, circuits and the like for controlling and routing electric power.

Although discussed with respect to a power line BUS <NUM>, the system of the present invention may further and/or alternatively communicate with one or more networks through a variety of components such as wireless access points, transceivers and so forth, and any associated software employed by a variety of components (e.g., drivers, configuration software, and so on). As further shown, the control device <NUM> may be in communication with each drive tower controller <NUM>, <NUM>, <NUM>, <NUM> to control movement of the irrigation system <NUM>. Further, the control device <NUM> may preferably further include multiple inputs and outputs to receive data from sensors and other monitoring devices as discussed further below.

With reference now to <FIG>, further aspects of the present invention shall now be further discussed. As shown in <FIG>, the system of the present invention <NUM> may preferably include an input pump <NUM> providing water (or another applicant) at given flow rate into the irrigation span <NUM> for delivery to selected sprinklers <NUM>, <NUM>. According to a preferred embodiment of the present invention, the inlet pump <NUM> is preferably programmed to run at a fixed flow rate, which may for example be <NUM> gpm.

As further shown in <FIG>, a preferred system of the present invention may preferably further include a water flow meter <NUM> which may preferably provide a direct measurement of the water flow rate to the system controller <NUM>. As discussed above, the controller <NUM> of the present invention may preferably include an irrigation prescription module <NUM>. According to preferred embodiments of the present invention, the irrigation prescription module <NUM> may preferably receive pump and water flow rate data from the inlet pump <NUM> and/or the water flow meter <NUM>. Further, the irrigation prescription module <NUM> may preferably manage the water flow rate at a constant level (i.e. <NUM> gpm) while maintaining the water pressure at the sprayers <NUM>, <NUM> at their rated level (i.e. <NUM> psi) as discussed further below.

According to a further preferred embodiment, the irrigation prescription module <NUM> may preferably interface with the controller <NUM> to provide updated drive instructions to the various drive control systems <NUM> of the irrigation system <NUM>. Still further, the irrigation prescription module <NUM> may preferably further interface with one or more valve controllers <NUM> to control valves <NUM>, <NUM> which adjust water application rates by the sprayers <NUM>, <NUM>.

With reference now to <FIG> and <FIG>, a first exemplary method <NUM> for use with the system of the present invention will now be further discussed. As shown in <FIG>, at a first step <NUM>, the system receives and stores irrigation system information. Preferably, the stored irrigation information may preferably include the sprinkler specifications, required flow rates, application depth at <NUM>%, and minimum pressure requirements of the sprinkler package and/or irrigation machine. In a next step <NUM>, the system preferably receives and stores an irrigation plan to be executed. The irrigation plan may be as simple as a percent of speed, or target application depth, or as complex as an individual sprinkler variable rate irrigation prescription. In a next step <NUM>, the operator or system may preferably determine the flow rate of applicant available to the irrigation machine. In a next step <NUM>, the system preferably compares the available flowrate to the currently required flowrate based on at least one of the following: sprinkler package required flowrate, current pulse rate, current ground speed reduction, and VRI prescription. At a next step <NUM>, the system preferably determines if the available flowrate is greater than the required flowrate. If so, at a next step <NUM>, the system then executes the irrigation plan. If not, at a next step <NUM>, the system preferably adjusts the pulse rate of the system sprinklers to maintain the required flow rate needed by the machine. At a next step <NUM>, the system then calculates and selects a lower ground speed required to match the irrigation prescription (i.e. the amount of applicant required) for the target area. Accordingly, the system may preferably select a ground speed which delivers the target amount of a given applicant at the selected pulse rate for the sprinklers. In an alternate preferred embodiment, the pulse rate and/or machine ground speed may be adjusted by the ratio of Available Flow Rate divided by the Required Flow Rate.

Once selected, at a next step <NUM>, the system preferably then executes the irrigation plan. Once execution of the irrigation plan <NUM> begins, the system preferably continuously monitors the available and required flowrates <NUM>, <NUM> and adjusts the pulse rate and machine speed as necessary to ensure the required machine flowrate always equals or is less than the available flow rate, thus ensuring that the actual application depth meets the target application depth. In addition to, or in lieu of, adjusting the ground speed, the present system may adjust other machine/ prescription parameters such as (but not limited to): target area, irrigation times, watering rate, start angles, end angles, inner sprinkler radius, and outer sprinkler radius. According to alternative preferred embodiments, the system of the present invention may preferably also (or alternatively) adjust the mixture rates of one or more applicants in response to any of the above VRI prescription adjustments and/or based on the Available Flow Rate to Required Flow Rate ratio.

With reference now to <FIG>, a further alternative embodiment of the present invention shall now be discussed in which the flow rate is adjusted based on the measured pressure(s) of the irrigation system. As discussed further below, this relationship may be pre-calculated and stored as a look-up table of flow rate adjustments based on measured pressures. According to further aspects of the present invention, this relationship preferably allows the use of water pressure alone to determine and adjust flow rates. Hence pressure measurements may be used instead of flow rate measurements to compensate for reductions in available flow rates and/or variations between available and required flow rates.

With reference now to <FIG> and <FIG>, a second exemplary method <NUM> for use with the system of the present invention will now be further discussed. As shown in <FIG>, at a first step <NUM>, the system receives and stores irrigation system information. Preferably, the stored irrigation information may preferably include the sprinkler specifications, required flow rates, application depth at <NUM>%, and minimum pressure requirements of the sprinkler package and/or irrigation machine. In a next step <NUM>, the system preferably receives and stores an irrigation plan to be executed. The irrigation plan may be as simple as a percent of speed, or target application depth, or as complex as an individual sprinkler variable rate irrigation prescription.

In a next step <NUM>, the operator or system determines the actual (measured) pressure of applicant in the irrigation pipe. In a next step <NUM>, the system preferably compares the minimum required pressure to the actual pressure. At a next step <NUM>, the system preferably determines if the actual pressure is greater than the minimum required pressure for the sprinklers. If so, at a next step <NUM>, the system then executes the irrigation plan. If not, at a next step <NUM>, the system preferably adjusts the pulse rate of the system sprinklers to maintain the required pressure needed by the machine. At a next step <NUM>, the system then calculates and selects a lower ground speed required to match the irrigation prescription (i.e. the amount of applicant required) for the target area. Accordingly, the system will preferably select a ground speed which delivers the target amount of a given applicant at the selected pulse rate for the sprinklers.

Once selected, at a next step <NUM> the system preferably then executes the irrigation plan.

Once execution of the irrigation plan begins, the system preferably continuously monitors the actual irrigation machine pressure <NUM> and adjusts the pulse rate and machine speed as necessary to ensure the actual machine pressure always equals or exceeds the minimum required pressure, thus ensuring the actual application depth meets the target application depth.

In an alternate preferred embodiment, the pulse rate and machine ground speed may preferably be adjusted by the ratio of Available Water Pressure divided by the Required Water Pressure. This ratio may preferably be calculated utilizing the flowrate to pressure relationship shown in <FIG> (either via an equation or look-up table) to translate pressures to and from flow rates.

As discussed above, by employing the exemplary methods of the present invention, a target application depth can be achieved along with the required minimum pressure even where the available flow rate varies or is less than the required minimum flow rate required by a sprinkler package. This allows, for example, use of a sprinkler package rated for a flow rate exceeding the available flow rate. According to alternative preferred embodiments, an irrigation system employing the present invention may further maintain a constant flow rate even as the target application depth of a given irrigation prescription varies.

Claim 1:
A method (<NUM>) for providing a constant flow rate within an irrigation system (<NUM>, <NUM>), wherein the method comprises: receiving and storing irrigation system information (<NUM>, <NUM>), which includes sprinkler (<NUM>,<NUM>) specifications; receiving and storing an irrigation plan (<NUM>, <NUM>) to be executed, wherein the irrigation plan comprises a target amount of an applicant to be applied to a target area by sprinklers of the irrigation system; determining an Available Flow Rate (AVR) for the irrigation system during execution of the irrigation plan; determining a Required Flow Rate (RFR) from data sources comprising: sprinkler package required flowrate, prescribed pulse rate, current ground speed, prescribed ground speed, and VRI prescription parameters with the sprinkler specifications; comparing the Available Flow Rate of the irrigation system to the Required Flow Rate to determine whether the Available Flow Rate (AFR) is greater than or equal to the Required Flow Rate (RFR); adjusting the pulse rate of a plurality of nozzles to reduce the Required Flow Rate (RFR) to at least the Available Flow Rate (AFR);
wherein the pulse rate is reduced by the ratio of AFR/RFR; and
calculating and adjusting the current ground speed (<NUM>) required to apply the target amount of applicant to the target area based on the adjusted pulse rate for the plurality of nozzles of all the sprinklers of the irrigation system.