Patent Application
20240418289
This document pertains generally, but not by way of limitation, to agricultural equipment.
An agricultural product (e.g., a fertilizer, carrier fluid, or the like) is optionally applied to a crop (e.g., one or more plants located in a farm field). In some examples, the agricultural product is applied with a sprayer system, for instance a sprayer mounted on a prime mover (e.g., a tractor, truck, all-terrain-vehicle, or the like). The sprayer system includes a valve, and the valve facilitates application of agricultural product to the crop (e.g., by spraying the agricultural product from a nozzle). In some examples, the valve is operated by a controller, for instance to translate the valve between an open position and a closed position. In the open position, the valve permits flow of the agricultural product through the valve. In the closed position, the valve does not permit flow of the agricultural product through the valve (e.g., between a valve inlet and a valve outlet). In some examples, the controller modulates the valve according to a duty cycle. The valve opens (or closes) in correspondence to the duty cycle of the modulation provided by the controller.
The present inventors have recognized, among other things, that a problem to be solved can include accurately applying an agricultural product to a crop. In an example, a valve controls the flow of a fluid through the valve. The valve is included in a sprayer system that applies the agricultural product to the crop (e.g., by spraying the agricultural product from a nozzle). In some examples, the valve is operated by a controller, for instance to translate the valve between an open position and a closed position. In the open position, the valve permits flow of the agricultural product through the valve. In the closed position, the valve does not permit flow of the agricultural product through the valve (e.g., between a valve inlet and a valve outlet).
In an example, the valve is operated for a specified duty cycle. The specified duty cycle optionally corresponds to a time duration between a first time interval when the controller modulates the valve (e.g., by generating a control signal) and a second time interval when the controller stops modulating the valve (e.g., by stopping the generation of the control signal). An actual duty cycle of the valve differs from the specified duty cycle for the valve. For instance, the mechanical response of the valve (e.g., to begin translating the valve toward the open position from the closed position) to the modulation provided by the controller does not perfectly correspond in time to when the controller intends for the valve to modulate. In an example, the actual duty cycle of the valve corresponds to a time duration between a third time interval when the valve actually begins transitioning between the open position and the closed position, and a fourth time interval when the valve actually completes the transition between the open position and the closed position. Accordingly, the specified duty cycle corresponds to a time duration that the controller modulates the valve (e.g., the time duration that the controller generates a control signal, or the like). The actual duty cycle of the valve corresponds to the time duration that the valve is in an open position (e.g., when a seal is disengaged from a valve seat to allow flow through the valve) in response to the modulation provided by the controller. The actual duty cycle varies from the specified duty cycle, for example due to mechanical tolerances of the valve, operating conditions (e.g., high pressure as opposed to low pressure), inertia of mechanical components of the system, signal processing delays or the like.
In some examples, the valve is operated to deliver a specified amount of agricultural product (e.g., a specified volume, specified flow rate, or the like) through the valve. In some approaches, an actual amount of agricultural fluid flowing through the valve differs from the specified amount because of differences between the specified duty cycle and the actual duty cycle of the valve. Accordingly, in some approaches the agricultural fluid is misapplied to the crop (e.g., too much agricultural product, too little agricultural product, or the like), and the misapplication affects one or more characteristics of the crop (e.g., growth, development, yield or the like).
The present subject matter can help provide a solution to this problem, such as by providing a system for applying agricultural product. The system includes a valve, and the valve optionally includes a solenoid having a coil configured to generate a magnetic flux. In some examples, the valve includes a moveable valve operator, and the valve operator translates with respect to the coil based on the generated magnetic flux. The valve operator optionally translates between a closed position and an open position according to a specified magnetic flux associated with a specified duty cycle, for instance the valve (ideally) opens with application of the magnetic flux and closes with arresting of the magnetic flux. In an example, the valve operator prevents flow through the valve in closed position, and the valve operator permits flow through the valve in the open position.
In an example, the system includes a dissipation element, such as a transient voltage suppression diode (“TVS”), having a dissipation characteristic (e.g., an amount of energy dissipated in proportion to a voltage across the dissipation element). In some examples, the dissipation element dissipates energy from the coil to arrest the magnetic flux and thereby initiate a rapid closing of the valve operator. For instance, a clamping voltage of a coil is increased and the energy in the coil (the increased voltage) is readily dissipated with the TVS. The dissipated energy corresponding initiates a rapid drop off in current and thereby decreases the magnetic flux that is based on current.
In some examples, the system includes a controller, and the controller receives measurements of one or more electrical characteristics of at least one of the coil or the dissipation element. The controller optionally determines an actual duty cycle of the valve operator using the measured electrical characteristics (e.g., through flux and electrical characteristics caused by movement of the operator relative to the coil). In an example, the controller determines a magnetic flux correction (e.g., for the coil, or the like) based on a difference between the actual duty cycle and the specified duty cycle of the valve operator. The controller optionally operates the valve operator according to the specified magnetic flux and the magnetic flux correction to guide the actual duty cycle of the valve operator toward the specified duty cycle of the valve operator.
Accordingly, the system for applying an agricultural product facilitates accurate and precise application of the agricultural product to a crop. For example, the controller guiding the actual duty cycle of the valve operator toward the specified duty cycle increases the accuracy (and precision) of an amount of agricultural fluid to the crop. For example, the system facilitates the application of a specified amount of agricultural product at a specified location (and/or at a specified time). Accordingly, agricultural product is accurately and precisely applied to the crop, for example to improve one or more crop characteristics (e.g., growth, development, yield or the like) and minimize waste of the agricultural product (e.g., waste due to misapplication).
This overview is intended to provide an overview of subject matter of the present patent application. It is not intended to provide an exclusive or exhaustive explanation of the invention. The detailed description is included to provide further information about the present patent application.
In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.
In an example, the reservoir tank 102 is integral with a prime mover 112 (e.g., a tractor, truck, combine, vehicle, or the like). In some examples, the reservoir tank 102 is a towed behind the prime mover 112 (e.g., the reservoir tank 102 is included with a trailer, or the like). The reservoir tank 102, in an example, includes an agricultural product mixed with a carrier fluid, such as water. In some examples, the carrier fluid and the agricultural product are mixed in-line prior to or at the sprayer boom 104. The nozzles 106 are positioned along the sprayer boom 104 to deliver the agricultural product (and the carrier fluid) to a crop (e.g., vegetables, fruit feed, or the like), for instance a crop located in an agricultural field 114. Crops include, but are not limited to, any product grown in an agricultural field, such as row and non-row based crops. Agricultural products include, but are not limited to, fertilizers, water, pesticides, fungicides, herbicides, or the like.
The agricultural sprayer 100 includes one or more controllers 116, for example the ECU 108 and the master node 110. In an example, the master node 110 operates in conjunction with the one or more ECU 108 to control delivery of the agricultural product from the reservoir tank 102, to the sprayer boom 104 and the associated nozzles 106 for delivery to the agricultural field or crop.
The master node 110 controls the master PWM valve 206 to provide a targeted system pressure (through modulated operation of a system pump associated with the master PWM valve 206), such that a desired droplet size of the agricultural product is generated at the nozzles 106. For example, environmental conditions, such as wind, humidity, rain, temperature, field characteristics, or user preference determine whether a smaller or larger droplet size of the agricultural product is preferred. By controlling a targeted system pressure (e.g., maintaining, changing with variations in flow rate or the like), the preferred droplet size is maintained with the system 200.
In the exemplary embodiment, each of the nozzles 106 is a smart nozzle that includes an electronic control unit (ECU) (e.g., ECU 108, shown in
The master node 110 controls one or more of a system pressure or system flow rate using, for example, the master pressure transducer 204 (or in other examples the flow meter, flow meter and pressure transducer together or the like) and the master pulse width modulation (PWM) valve 206. Although
In an example, the target system pressure is provided by a user, such as at the user interface 210 connected to the master node 110 by the nozzle CAN bus 208. In an additional example, the user also provides a target system flow rate (e.g., volume/area) at the user interface 210. In an example, the master node 110 provides one or more of the target system flow rate or the target system pressure to each of the one or more smart nozzles 106, such that each smart nozzle 106 (or each ECU, as discussed herein) determines an individual agricultural product flow rate (or pressure) for the smart nozzle 106. For example, the system target flow rate is divided by the number of nozzles 106 to provide a target agricultural product flow rate for each of the one or more nozzles 106. In an example, the master node 110 measures the flow rate (e.g., volume per time) with a master flow meter 202 and compares it with the overall target flow rate (e.g., designated by one or more of the user, crop type, soil characteristic, agricultural product type, historical data, or the like). The master node 110 is configured to determine a difference or error, if present, between the measured system flow rate and the target system flow rate. In such an example, the master node 110 provides the determined difference, by the nozzle CAN bus 208, to the individual nozzles 106 (or ECUs, as discussed herein). The one or more nozzles 106 receive the difference on the CAN bus 208 and adjust their pressure/flow/duty cycle curve using the difference (e.g., compensating for errors in the system) to reduce the error between the measured and target system flow rates (or reduce the error between the measured and target system pressures). Additionally, in at least some examples, the master node 110 reports the actual pressure, measured by the master pressure transducer 204, as well as boom 104 information, including, but not limited to, one or more of yaw rate, speed, number of smart nozzles of the boom, distance between smart nozzles on the boom, to the smart nozzles 106 (or ECUs, as described herein) for individual flow rate control (or pressure control) of each of the smart nozzles 106. For example, the information provided from the master node 110 is used in addition to nozzle characteristics to control the individual flow rate control of each smart nozzle 106. Nozzle characteristics include, but are not limited to nozzle position on a boom, length of the boom, nozzle spacing, target flow rate for the system, yaw rate of the boom, yaw rate of the agricultural sprayer, speed of the agricultural sprayer, the overall system pressure or flow rate, agricultural product characteristics, valve performance such as a moveable valve operator transition time (including differences between specified and actual duty cycles), or the like.
The system 200 is configured for installation on an agricultural sprayer (e.g., the agricultural sprayer 100, shown in
As shown in the embodiment of
Further, as shown in
In still another example, the system 300 includes one or more location fiducials associated with the system 300, the one or more location fiducials are configured to mark the location of one or more nozzles (or ECUs) of the plurality of nozzles on a field map (e.g., indexed with product flow rates, moisture content, crop type, agricultural product type, or the like). Optionally, each of the nozzles, nozzle groups, or ECUs 108 of the system is configured to control the agricultural product at individual rates according to the location of the one or more nozzles (or ECUs 108), the movement of the one or more nozzles relative to the field, another frame of reference or the like (and optionally in addition to the nozzle characteristics described herein). Further, each of the plurality of nozzles (or ECUs 108) is optionally cycled, such as on/off, according to the location of the nozzle (or location of a nozzle group or ECU 108) relative to a frame of reference, such as a field.
In an example, each nozzle ECU 108 is programmable to receive, track, or manipulate designated nozzle control factors (e.g., the specified duty cycle, the actual duty cycle, or the like). For example, each ECU 108 monitors one or more of nozzle spacing, target flow rate for the system, target pressure for the system, speed of the agricultural sprayer, yaw rate, nozzle location on the field, or the like. Such examples provide the benefit of comporting the system to user specifications, provide greater programmability of the system, and providing cost effective nozzle specific flow rate solutions. In yet another example, the ECUs 108 associated with each nozzle are instead consolidated into one or more centralized nodes that determine the individual flow rates of each of the respective nozzles in a similar manner to the previously described ECUs 108 associated with each of the nozzles.
The controllers 116 (e.g., the ECU 108, the master node 110, or the like) control the nozzle flow rate (or the timing of flow through the nozzle) based on a number of parameters, including, but not limited to: speed of the sprayer or boom, yaw rate, target system flow rate (e.g. volume/area), and on/off command at runtime. Such parameters permit the controllers 116 to calibrate the duty cycle curve (e.g., by adjusting the actual duty cycle of a valve) of each smart nozzle needed to achieve the target nozzle flow rate (or a target nozzle timing) of each of the smart nozzles. For instance, calibrating the duty cycle curve includes guiding an actual duty cycle of the nozzles (and their associated valves) to a specified duty cycle of the nozzles. Each smart nozzle is further configured according to nozzle spacing on the boom, location on the boom, and nozzle type. Further, in some examples, each smart nozzle regulates or controls the nozzle flow rate (or pressure) based on the location of the nozzle in the field (as described above).
As described herein, the agricultural sprayer 100 (shown in
In an example, and as described in greater detail herein, a system for applying an agricultural product (e.g., the sprayer 100, or the like) realizes specified operational flow performance out of a smart nozzle 106 despite factors that negatively affect performance by determining variations between the specified performance and the actual performance and instituting a correction (or corrections) at valves to achieve the specified performance. For instance, the system controls a specified duty cycle of a valve versus an actual duty cycle of the valve 304 with a correction (discussed herein) that guides the actual duty cycle to coincide with the specified duty cycle. In some examples the system includes a solenoid valve drive circuit and a solenoid valve monitoring circuit. In another example, the system includes (or utilizes) an algorithm for tracking a position of a moveable valve operator (e.g., a poppet, or the like) of the valve 304 based on, for example, monitoring of back-emf (BEMF) generated in a solenoid coil by the moving valve operator as it transitions between its open and closed positions in the valve 304. In another example, monitoring (e.g., capturing, recording, observing, cataloging, compiling, collecting, or the like) of the performance of the valve 304 optionally provides insight into valve health or nozzle faults and, for instance alerts a system user to a specific problem (e.g., with the user interface 210, shown in
In an example, the valve 304 is biased toward the closed position, for instance with a biasing element 418, such as a coil spring, leaf spring, elastomer, magnet, or the like. The biasing element 418 optionally biases the valve operator 400 toward the closed position. In an example, the moveable valve operator 400 includes an operator flange 401 and the housing 406 includes a flare 411 The biasing element 418 (a spring in this example) is coupled between the operator flange 401 and the flare 411. In this example, the biasing element 418 provides a force between the housing 406 and the valve operator 400 to bias the valve operator 400 toward the closed position.
In some examples, the valve 304 operates by applying a voltage potential to a coil 420 (e.g., a winding of wire, or the like) that generates current in the coil 420. The coil 420 generates magnetic flux when current flows through the coil 420. In an example, the moveable valve operator 400 translates with respect to the coil 420 based on the magnetic flux generated by the coil 420. The current flowing through the coil 420 optionally magnetizes the lug 404 (and the valve operator 400) of the valve 304. For instance, the lug 404 is ferromagnetic, and a magnetic pole is established that attracts (e.g., draws, pulls, pushes, drives, or the like) the valve operator 400 toward the lug 404. Accordingly, the valve 304 optionally includes a solenoid 421, and the solenoid 421 includes (but is not limited to) the valve operator 400, the lug 404, and the coil 420.
The valve 304 optionally includes a magnetic flux frame 422 surrounding one or more of the lug 404 or the valve operator 400. The magnetic flux frame 422 encapsulates the magnetic field between the lug 404 and valve operator 400 and accordingly concentrates the magnetic field. For instance, the magnetic flux frame 422 enhances bounding of flux generated by the coil 420 to concentrate the 5 magnetic field between the lug 404 and the valve operator 400.
Referring again to
A generated counter current (e.g., back electromotive force or back EMF) and corresponding magnetic field are examples of characteristics that alter the performance of the valve 304 relative to a specified duty cycle. For example, as the valve operator 400 moves toward the open position a counter current is generated in the coil 420 as the flux linkage changes because of a change of magnetically permeable material within the magnetic field (e.g., more of the valve operator having a higher magnetic permeability moves into the magnetic field and displaces fluid having a lower permeability). As the valve opens the flux linkage of the valve 304 changes due to the valve operator 400 occupying the previously fluid filled fluid gap 500. Conversely, when the valve operator 400 is in the closed position (
The direction of the current generated in the coil 420 and its magnetic field caused by the moving valve operator 400 opposes the initial magnetic field of the coil 420 (e.g., the magnetic field generated by a current flowing through the coil 420). In an example, opposition of the initial magnetic field decreases the initial magnetic field generated by the coil 420 (e.g., according to Lenz's Law, or the like). Thus, in some examples, as the valve operator 400 moves nearer the coil 420 (or within the housing 406), the magnitude of current in the coil is reduced to oppose the originally created field caused by the current applied to the coil 420 (e.g., a ramping current, or the like).
The nozzle control system 600 includes one or more sensors 602 that facilitate monitoring of one or more electrical characteristics (e.g., current, voltage, resistance, or the like) of components of the system 600. For example, the nozzle control system 600 includes a coil characteristic sensor 604, for instance included in series with the coil 420. In an example, the coil characteristic sensor 604 determines (e.g., measures, monitors, obtains, provides, evaluates, observes, or the like) the magnitude of current through the coil 420 (or voltage across the coil 420).
In an example, the system 600 includes a nozzle controller 606, and the nozzle controller 606 monitors the electrical characteristics of the system 600. For instance, the controller 606 is in communication with the sensors 602, and the controller 606 monitors the sensors 602. For example, the controller 606 monitors the magnitude of the current through the coil 420 (e.g., as determined by the characteristic sensor 604). In some examples, the controller 606 performs one or more mathematical operations upon the monitored electrical characteristics. For instance, the controller 606 monitors one or more rates of change of the current through the coil 420.
As discussed herein, movement of the valve operator 400 facilitates flow through the valve 304. In an example, movement of the valve operator 400 (e.g., with respect to the housing 406, shown in
The valve 304 is optionally closed (e.g., to inhibit flow in the channel 412 between the valve inlet 414 and the valve outlet 416) by dissipating the magnetic field between the lug 404 and the valve operator 400. For example, the magnetic field between the lug 404 and the valve operator 400 is dissipated and the biasing element 418 is thereby freed to overcome the attraction force between the valve operator 400 and the lug 404. The valve operator 400 is biased with the biasing element 418 toward the closed position. In an example, the current flowing through the coil 420 is reduced to dissipate the magnetic field generated by the coil 420. For example, the voltage potential applied to the coil 420 is removed from the coil 420. When the voltage potential is removed, the current flowing through the coil 420 will decrease and the magnetic field generated by the coil 420 will also begin to dissipate (e.g., decay, reduce, decrease, diminish or the like). When the magnetic field has sufficiently dissipated, the biasing element 418 will bias the valve operator 400 back towards the valve seat 409 and the closed position.
As the valve operator 400 begins to transition from the open position (shown in
In an example, the valve control system 600 includes a power conditioning system 608. The power conditioning system 608 provides a drive voltage potential to operate the system 600 (including the valve 304 having the coil 420). In some examples, the coil 420 acts like an inductor, and the current flowing through the coil 420 does not change instantaneously. The rate of adding energy into the coil 420 is optionally increased, for example by increasing the drive voltage potential (e.g., a voltage applied across the coil 420 with the power conditioning system 608) to overcome the inductance of the coil 420.
In some examples, the open time for the valve 304 is improved by reducing the force of the biasing element 418 to make the biasing force easier to overcome. Increasing the rate that energy is dissipated from the coil 420 (and corresponding dissipation of the magnetic field) optionally reduces the close time of the valve 304 (e.g., a time duration for the valve operator 400 to transition from the open position to the closed position). Further, reducing the amount of energy to be dissipated from the valve 304 (e.g., the coil 420) optionally reduces the close time of the valve 304. An increase in the spring constant of the biasing element 418 aids in returning the valve operator 400 to the closed position (e.g., with the seal 408 engaged with the valve seat 409) though it may conversely increase the duration of valve open as the stiffer biasing element 418 opposes opening.
In some examples, the coil 420 has a defined resistance, and when a potential is applied across the coil 420, a first amount of energy will be dissipated by the coil 420 to build the magnetic field. A second amount of energy is dissipated due to the resistance of the coil 420 (e.g., as heat). Once the valve 304 transitions from the closed position to the open position, the amount of magnetic field needed to maintain the open position of the valve operator 400 is reduced because the initial additional force to separate the seal 408 from the seat 409 against the fluid pressure of the valve 304 is reduced (e.g., in comparison to when the valve operator is in the closed position). With the valve operator 400 in the open position, the fluid gap 500 (shown in
In an example, the system 600 includes a coil drive voltage regulator 610, for instance to facilitate operating the power conditioning system 608 at a fixed, or nearly fixed voltage. The controller 606 optionally modulates one or more of a high side switch 612 and a low side switch 614, for instance to provide energy to the coil 420. The high side switch 612 and the low side switch 614 are optionally located on either side of the coil 420. For example, the high side switch 612 is included in the system 600 on a first side of the coil 420. In an example, the low side switch 614 is included in the system 600 on a second side of the coil 420. In an example, current flows through the coil 420 (and energizes the coil 420) when the switches 612, 614 are closed. In some examples, one or more of the switches 612, 614 are normally open, and modulation of the switch closes a circuit and allows current to flow through the switches 612, 614. For instance, the switches 612, 614 are normally open to facilitate conservation of power in the system 600 (e.g., by selectively supplying power to the system 600 as needed).
In some examples, the system 600 includes one or more dissipation elements 616, for instance a first dissipation element 618 and a second dissipation element 620. The dissipation elements 616 include (but are not limited to) a flyback diode, freewheeling diode, clamp diode, transient voltage suppression diode, resistor, capacitor, or the like. In an example, the first dissipation element 618 includes a freewheeling diode, and the dissipation element 618 facilitates recirculation of current through the coil 420 to facilitate the maintenance of the magnetic field with less energy. The dissipation element 616 optionally have a dissipation characteristic and dissipate energy within the system 600, for instance from the coil 420. In some examples, the dissipation element 616 helps recirculate energy within the system 600 (e.g., by recirculating current through the freewheel path 632, or the like). For example, the dissipation element 618 facilitates recirculation of current through the coil 420 (with corresponding maintenance of the magnetic field) when the high side switch 612 is open (e.g., to inhibit current flow through the switch 612) and the low side switch 614 is closed (e.g., to allow recirculating current to flow between the switch 614 and the dissipation element 616 with the intervening circuit having the coil 420 and ground).
The second dissipation element 620, for example, facilitates deenergizing of the coil 420. For instance, the dissipation element 620 includes a clamping diode, and the dissipation element 620 quickly dissipates recirculating energy in the system 600 (e.g., removes, reduces, diminishes, dumps, minimizes or the like) from the coil 420 (or the system 600) when both switches 612, 614 are opened. Accordingly, current flowing through the coil 420 is forced to divert to a flyback path (e.g., the flyback path 634, or the like) for dissipation across the dissipation element 620 (e.g., a clamping diode).
As described herein, the controller 606 monitors the sensors 602. For instance, the controller 606 determines when the valve operator 400 moves based on the monitoring of electrical characteristics with the sensor 604 (e.g., a decrease in current corresponding to movement of the valve operator 400 with respect to the housing 406). The system 600 optionally includes a sense resistor 622. For instance, the sense resistor 622 facilitates monitoring of electrical characteristics of the system 600 (e.g., current through the coil 420), for example with the controller 606. In an example, the controller 606 monitors the sensors 602 to correspondingly monitor the mechanical response of the valve operator 400 (e.g., movement of the valve operator 400 between the closed position and the open position). Monitoring of the mechanical response of the valve operator 400 facilitates determining the actual duty cycle of the valve 304.
In some examples, the coil characteristic sensor 604 includes the sense resistor 622. For example, the sense resistor 622 facilitates determining electrical characteristics of the coil 420. Monitoring of the electrical characteristics of the coil 420 facilitates monitoring of movement of the valve operator 400, for instance to determine when the valve operator 400 begins to transition from the closed position to the open position. In an example, the sense resistor 622 (in cooperation with the controller 606) facilitates determining when the valve operator 400 has fully transitioned to the open position (from the closed position). In some examples, the sense resistor 622 is located in series with the coil 420. In an example, the sense resistor 622 is located in the system 600 between the coil 420 and the switch 612. The sense resistor 622 is optionally located in series with the power conditioning system 608 and the coil 420. Thus, the coil characteristic sensor 604 determines electrical characteristics of the coil 420 and facilitates monitoring of the electrical characteristic of the coil 420 with the controller 606. Accordingly, monitoring of the electrical characteristics of the coil 420 facilitates determining when the valve operator 400 actually moves (e.g., because the mechanical response of the valve 304 differs from the electrical signals operating the valve 304).
In an example, the sensors 602 include a dissipation characteristic sensor 624. For instance, the dissipation characteristic sensor 624 determines one or more electrical characteristics of the dissipation elements 616. For example, the dissipation characteristic sensor 624 determines a voltage across the second dissipation element 620, for instance by determining a voltage at a dissipation voltage node 626 between the coil 420 and the second dissipation element 620.
In an example, the dissipation characteristic sensor 624 facilitates monitoring of movement of the valve operator 400. For instance, the controller 606 optionally monitors the dissipation characteristic sensor 624 to monitor the mechanical response of the valve operator 400 (e.g., movement of the valve operator 400 between the open position and the closed position). The controller 606 monitors the sensor 624 to determine when the valve operator 400 begins to transition from the open position to the closed position. In another example, the sense resistor 622 (in cooperation with the controller 606) facilitates determining when the valve operator 400 has fully transitioned to the closed position (from the open position).
The system 600 optionally includes one or more signal processors 628. For instance, the signal processors 628 provide signal conditioning, amplification, or the like for components of the system 600. In an example, the signal processors 628 facilitate monitoring of electrical characteristics by the controller 606. For example, the signal processors 628 condition electrical characteristics of the system 600 for monitoring by the controller 606. For instance, the signal processors 628 allow the controller 606 to monitor the voltage at the dissipation voltage node 626. The signal processors 628 allow the controller 606 to monitor current flowing through the coil 420, for example by monitoring the voltage across the sense resistor 622.
The controller 606 (in cooperation with the sensor 604, shown in
Further, flow 709 agricultural product or the like through the valve of the valve system 600 is shown in the sixth plot (lower most) in
As shown in
In one example, at time T0, the valve operator 400 is a closed position as shown with the valve operator position plot 708. At time TO both of the high side switch 612 and low side switch 614 (shown in
The plotted coil electrical characteristic 704 shows a plurality of inflection points 710. As previously described, as the valve operator 400 begins to move (e.g., from closed to open) at approximately T1 a counter current is generated, and the counter current is graphically shown in
The fifth plot of
In some examples, the controller 606 (shown in
Referring to
At time T2, the valve operator 400 is at the open position, and at time T3 the controller 606 optionally reduces the current and associated magnetic field in the solenoid 421 for instance to save energy. For instance, the controller 606 maintains the current at a lower level recognized to retain (e.g., maintain) the valve operator 400 in the open position. In an example, the current is modulated as shown with the sawtooth wave at T3 (e.g., with selective opening and closing of the high side switch 612 while the low side switch 614 is closed). For example, the electrical resistance in the coil 420 and loss in one or more of the dissipation elements 616 and switches 612, 614 causes the coil electrical characteristic 704 to decay. In order to maintain the field generated by the coil 420, the high side switch 612 is modulated to add energy to the solenoid 421 (e.g., the coil 420, or the like) as needed to maintain the valve operator 400 open while minimizing power usage.
The modulated current maintains the magnetic field in the solenoid 421 with a slight imbalance (e.g., relative to gravity, fluid pressure, bias from the bias element or the like) to ensure retention of the valve operator 400 in the open position. In an approach, the inductance of the coil 420 is higher and the coil electrical characteristic 704 would follow the path indicated by a second dotted line 716 in the coil electrical characteristic 704 until it had saturated near a maximum value (e.g., approaches a limit, or the like) if the high side switch 612 was maintained in the on state.
Modulating (e.g., selectively opening and closing) the high side switch 612 circulates current in the system 600 at a level to generate a magnetic flux between the lug 404 and the valve operator 400 so as to maintain the position of the valve operator 400 (e.g., in the open position). Accordingly, the system 600 modulates the switch 612 to provide a force imbalance incident upon the valve operator 400 and ensure retention of the valve operator 400 in the open position while reducing the power needed to maintain the position of the valve operator 400.
In some examples, the high side switch 612 is modulated between the on state and the off state (e.g., by selectively closing and opening the switch 612) while maintaining the low side switch 614 in the on (e.g., closed) state. Modulating the high side switch 612 while the low side switch 614 is in the on state causes current to flow through the freewheel path 632 that, in some examples, includes the low side switch 614, the first dissipation element 618, the sense resistor 622, and the coil 420 (shown in
In an example, during a rising edge of the low side switch control, a hit state is initiated in the high side switch 612 and the controller 606 starts recording electrical characteristics, for example by monitoring the current flowing through the coil 420. The controller 606 analyzes the current data collected to determine if the valve operator 400 has translated between the open position and the closed position. In some examples, the controller 606 waits for a specified delay and repeats the analysis if a translation is not detected.
In an example, when the controller 606 determines the valve operator 400 has translated, the controller 606 optionally stops monitoring the electrical characteristics of the coil 420 and maintains the position of the valve operator 400 (e.g., by modulating the switch 612, or the like). Optionally, the controller 606 waits for a specified duration for a compare event in the low side switch 614 timer. When a compare event occurs, the low side switch 614 and the high side switches 612 are turned to an off state. Accordingly, current is forced to recirculate in the flyback path 634 to be dissipated across the second dissipation element 620 (e.g., a clamping diode, or the like). At this point, the controller 606 monitors the dissipation characteristic 706 (e.g., a flyback voltage, or the like). At the end of a wait period (e.g., either 10 ms or the until the next update event), the controller 606 analyzes the dissipation characteristic for transition signature 714.
The valve operator 400 is optionally moved to the closed position, for instance at time T4. In an example, both the high side switch 612 and the low side switch 614 are transitioned to the off state (e.g., to inhibit current flow through the switches 612, 614). With the switches 612, 614 in the off state, current is inhibited from flowing through the freewheel path 632. Accordingly, the current recirculating in the coil 420 flows through the flyback path 634 (see
In between T5 and T6, the dissipation characteristic (voltage) 706 is saturated, current decreases as shown in the third plot, and the magnetic field generated by the coil 420 decreases quickly. As the field decreases, the corresponding force retaining the open position of valve operator 400 against the fixed lug 404 dissipates—and the force provided by the biasing element 418 (shown in
In one example, Lenz's law indicates that the current generated by the valve operator 400 transitioning to the closed position opposes the change in the characteristic 706 as a result of the collapsing magnetic field. Thus, in an example, instead of seeing the voltage decay of the coil 420 (e.g., an inductor, or the like) that is discharging (represented by a third dotted line 720), the dissipation characteristic 706 will rise and then fall relative to the previous decay until the valve operator 400 has completed its movement (e.g., translation, transition, stroke, displacement, change, shift, or the like) from the open position (e.g., at T7) to the closed position (e.g., at T8). In an example where the field generated by the solenoid 421 is insufficient to maintain the valve operator 400 in the open position, the valve operator 400 will transition to the closed position prior to turning off the switches 612, 614. At time T8, the valve operator 400 has fully completed movement to the closed position, and any remainder of the field generated by the coil 420 decays based on the lower inductance in the coil 420 since the fluid gap 500 has been reintroduced. In some examples, the valve 304 remains in this de-energized state until time TC which is the duration of a cycle.
Accordingly, the time duration between T1 (e.g., when the valve operator 400 begins moving toward the open position) and T8 (e.g., when the valve operator 400 moves to the closed position and the flow 709 through the valve 304 stops) corresponds to an actual duty cycle 713 of the valve 304. For example, the actual duty cycle 713 of the valve 304 corresponds to the time between actual opening of the valve operator 400 with beginning of translation to the open position at T1 (in contrast to the preceding operation of the switches 612, 614 at TO) and a translation stop time of the valve operator 400 at T8 (when the valve operator 400 is in the closed position). As shown in
As discussed herein, the system 600 guides the actual duty cycle 713 of the valve 304 to comport with the specified duty cycle 701. For example, the specified duty cycle 701 corresponds to the portion of the low side switch state 700 (e.g., from T0 to T4). The actual duty cycle 713 corresponds to the valve operator position 708 shown in the fifth plot of
The system 600 applies a correction, for example a magnetic flux correction, to the specified duty cycle 701 to guide the actual duty cycle 713 of the valve 304 toward the specified duty cycle. In an example, the correction applied to the specified duty cycle corresponds to the error determined between the actual duty cycle and the specified duty cycle. As one representative example, opening of the valve in the actual duty cycle 713 is delayed by 0.005 seconds (5 milliseconds or 5 ms) relative to the specified duty cycle 701. The system modulates the switches 612, 614 to advance the timing of the specified duty cycle by 5 ms to guide the actual duty cycle 713 of the valve 304 to the specified duty cycle 701 (e.g., with a modified specified duty cycle). Thus, the system 600 adjusts (e.g., corrects, modulates or the like) the magnetic flux generated by the coil 420 to achieve actual operation of the valve operator 400 (opening, closing, and timing of the same) according to the specified duty cycle. Accordingly, the system 600 minimizes error between the specified duty cycle 701 and the actual duty cycle 713 to improve the performance of the valve 304 (e.g., to open or close the valve operator 400 at a desired point in time, permit flow through the valve 304 for a specified period of time or the like).
Referring first to
The actual duty cycle 804 (e.g., mechanical performance of the valve 304) is shown in the second plot of
The system 600 including for example the feedback control loop 1100 (of
The magnetic flux correction 810 increases or decreases the flux in the valve 304 to accordingly trigger a change in one or more of valve opening or valve closing (e.g., opens, closes earlier, later, one earlier one later, combinations of the same or the like) relative to the previous actual duty cycle 804. The applied duty cycle 808 (based on the specified duty cycle 800 with the magnetic flux correction 810), when implemented with the system 600, provides the actual duty cycle 804′ shown in the third plot having a duration, percentage or the like), in this example 25 ms, relative to the actual duty cycle 804 length of 22.3 ms. The time length of the actual duty cycle 804′, 25 ms, corresponds to the specified time length of 25 ms of the specified duty cycle 800. The actual duty cycle 804′ is the actual valve performance of the valve 304 driven with the specified duty cycle 800 and the magnetic flux correction 810, and the actual duty cycle 804′ has a duration of 25 ms that matches the duration of the original specified duty cycle 800 shown in the upper plot of
The controller 606 optionally analyzes the samples (e.g., one or more of an analog signal, a digital signal, or the like) to detect a second peak value that exceeds the second valve operator transition value. For instance, the valve operator 400 may bounce within the valve body 402, thereby causing multiple peak values above the minimum valve operator transition value. Accordingly, at 910, the controller detects when the electrical characteristics exceed a bounce threshold to determine when the valve operator 400 has moved to the open position (e.g., the valve operator position 708 at T3, shown in
The controller 606 determines when all values are defined at 914, such as by detecting when the value of the electrical characteristics of the system 600 exceed one or more of the thresholds described herein (e.g., a noise threshold, transition threshold, bounce threshold, or the like). At 916, when all values are defined, the controller 606 determines that the valve operator 400 did move (e.g., valve operator 400 is not stuck, bouncing, or the like) and proceeds to the hold state (e.g., by utilizing a hit-and-hold algorithm). If all values were not defined, at 918 the controller 606 determines that a full transition of the valve operator 400 did not occur and determines whether a wait duration has exceeded a maximum transition time threshold, such as a threshold correlating to the maximum hit duration of the hit-and-hold algorithm. In another example, the maximum transition time threshold correlates with a point when the field in the coil 420 is nearly saturated. If the wait duration has not exceeded the maximum transition time threshold, the controller 606 returns to 904 and analyzes samples of the electrical characteristics of the system 600. If the wait duration exceeds the maximum transition time threshold, the controller 606 determines that the valve operator 400 has not transitioned (e.g., the valve operator 400 is stuck or the operating pressure is too high) and the controller 606 records that the valve operator 400 did not transition.
In an example, the controller 606 when the controller 606 records that the valve operator 400 did not transition, the controller 606 provides a notification that the valve operator 400 did not transition (e.g., by displaying a message on a user interface, or the like). For example, the controller 606 transmits a notification to a user interface (e.g., a screen, dashboard, console, light emitting diode, pixel, or the like) to indicate to a user that the valve operator 400 did not transition. In another example, the notification provides the user with information that the duty cycle could not be implemented, for instance because the valve operator 400 remained open (or closed) instead of transitioning according to the specified duty cycle. Failure to implement the duty cycle is indicative in some examples of poor valve health, for example over or under application of an agricultural product, plugging, inability by the valve to achieve the specified duty cycle. A failure to implement the duty cycle triggers an implementation of a magnetic flux correction in one example. If the correction is implemented and performance is still out of line with the specified duty cycle a further indication is optionally provided of poor valve health.
At 1004, the controller 606 analyzes the samples collected during translation of the valve operator 400. In some approaches, sampling the magnitudes of the sample values is unreliable at indicating valve operator 400 transition times. In an example, the controller 606 utilizes a derivative of the sample values (e.g., one or more electrical characteristics of the system 600, such as characteristics 704, 706) to determine whether the valve operator 400 has transitioned. The controller 606 optionally utilizes a stream derivative using, for instance a 9-sample window. For example, the controller 606 uses the Savitzky-Golay stream derivative method to compare one or more electrical characteristics of the system 600 to one or more of the valve operator translation signatures 714. In an example, as the stream derivative is calculated, the controller 606 analyzes the samples to look for one or more of the inflection points 710, 718 or the like in the electrical characteristics (or derivatives of the electrical characteristics) of the system 600. In another example, the valve operator translation signature 714 corresponds to one or more of the inflection points 710 of the coil characteristic 704. In yet another example, the valve operator translation signature 714 corresponds to one or more of the inflection points 718 of the dissipation characteristic 706. For instance, the inflection points 710, 718 include one or more of a change in magnitude of a derivative of the characteristic 704 (or the characteristic 706), such as an increase in the rate that the slope is decreasing; a change in sign of the slope of the characteristic 704 (or the characteristic 706); a change in sign of the derivative of characteristic 704 (or the characteristic 706); peaks and valleys; global maxima; global minima; local maxima; local minima; or the like.
In an example, at 1006 the controller 606 detects a first inflection point (e.g., a peak, such as inflection point 718A) in the collected samples, and the first inflection point correlates to the time (e.g., for the characteristic 706 at T5, shown in
For instance, when the system 600 decreases variations in the open time of the valve 304 (between specified open and actual open), the controller 606 optionally increases the field generated by the coil 420. The increase in the generated field corresponds to an increase in power supplied to the coil 420. In some examples, variations between duty cycles are mitigated by monitoring the feedback of the coil characteristic sensor 604 and dissipation characteristic sensor 624, for instance to determine when the valve 304 actually transitions between the open position and the closed position (e.g., when the valve 304 actually strokes).
In an example, the controller 606 determines how the valve operator 400 actually moved for a cycle of the valve 304. The controller 606 compensates for variability in movement of the valve operator 400 (e.g., a difference between specified duty cycle and actual duty cycle) with an applied duty cycle 1108 that is based on the specified duty cycle with a magnetic flux correction. For example, at 1112, one or more of the switches 612, 614 are modulated according to the applied duty cycle 1108 (or specified duty cycle if no magnetic flux correction is present) to thereby open and close the valve 304. The corresponding actual duty cycle 1110 is the output of the modulated switching at 1112. The algorithm 1100 at 1114 includes determining the valve operator duty cycle. For example, the controller 606 monitors one or more characteristics, such as the electrical characteristics 704, 106 (that represent opening and closing of the valve), also referred to herein as the actual duty cycle 1110 (or the actual duty cycle 804 in
In
For instance, at 1112, system feedback is conditioned into the duty cycle correction 1118 (e.g., an error offset, or the like) and used to modulate the low side switch 614 with the applied duty cycle 1108 that differs from the specified duty cycle 1102 to guide the actual duty cycle 1110 of the valve 304 to the specified duty cycle 1102. Accordingly, the system tightly controls the output of the valve 304 (e.g., flow of an agricultural product, or the like) based on a desired target output (e.g., valve flow rate, agricultural product volume or the like).
As described herein, at 1116, the controller 606 implementing the algorithm 1100 determines the duty cycle correction 1118 (e.g., a duration, percentage or the like that represents the magnetic flux correction) based on error (e.g., differences) between the specified duty cycle 1102 and the actual duty cycle 1110. The duty cycle correction 1118, when implemented at the coil 420 of the valve 304 corresponds to the magnetic flux correction. The duty cycle correction 1118 is combined with the specified duty cycle 1102 at the summation block 1104 to accordingly generate the applied duty cycle 1110. Accordingly, the duty cycle correction 1118 is applied to the specified duty cycle 1102 to generate the applied duty cycle 1108 that guides the valve performance (e.g., the actual duty cycle 804′ described herein and shown in
As described herein, the controller 606 monitors feedback such as electrical characteristics that correspond to mechanical performance of the valve 304 as the valve operator transitions (e.g., between with an open stroke or a close stroke). The controller 606 optionally compiles one or more metrics related to valve health or valve performance relative to other valves in the system (e.g., to notify a user that performance of one or more of the valves is degraded, for instance below a performance threshold). In another example, the controller 606 compiles a health metric based on the correction, such as the magnetic flux correction or duty cycle correction 1118 (in
For example, a magnitude of the duty cycle correction (e.g., determined with the algorithm 1100, shown in
In another example, when the duty cycle correction 1118 exceeds 10 percent of the specified duty cycle (e.g., a duty cycle correction exceeding 0.010 ms for a duty cycle time of 0.100 ms), the controller 606 provides a notification that the health value of the valve 304 is decreasing. For example, the health value of the valve decreases below 100 total health points if the duty cycle correction 1118 exceeds 10 percent of the specified duty cycle 1102. The health value of the valve 304 optionally decreases in a graduated manner (e.g., linearly, exponentially, logarithmically, or the like) as the duty cycle correction 1118 increases above 10 percent of the specified duty cycle 1102. For example, the controller 606 provides a notification that the valve 304 has 50 health points (out of 100 total health points) when the duty cycle correction 1118 exceeds 15 percent of the specified duty cycle 1102 (e.g., the duty cycle correction exceeding 0.015 ms for a duty cycle time of 0.100 ms). In another example, the controller 606 provides a notification that the valve 304 has 0 health points (out of 100 total health points) when the duty cycle correction 1118 exceeds 20 percent of the specified duty cycle 1108 (e.g., the duty cycle correction exceeding 0.020 ms for a duty cycle time of 0.100 ms). In some examples, the controller 606 provides a notification that the valve 304 needs service, for instance when the duty cycle correction 1118 exceeds 25 percent of the specified duty cycle 1102 (e.g., the duty cycle correction exceeding 0.025 ms for a duty cycle time of 0.100 ms). Accordingly, the controller 606 utilizes the duty cycle correction 1118 to assess the health of the valve 304 and notify a user regarding the health of the valve (e.g., by displaying a health value including health points of the valve, or the system 600, with a user interface).
In some examples, pressure changes quickly at the valve outlet 416 once the seal is broken (on the open stroke) or sealed (on the close stroke). As the valves low output depends on the pressure at the outlet, the system provides a specified output when the system utilizes the subject matter described herein. For instance, the error offset metric is helpful for determining valve health between valves. The system provides operation conditions as similar as possible between valves of the system, and in some examples the system compares how much offset a given valve has and determines if the system is out of specifications (e.g., outlet restrictions in the case of blocked tip detection).
In some examples, a plumbing system of a sprayer has a pressure drop along the boom that varies from nozzle location to nozzle location that depends on the amount of flow going to each nozzle location. This variable pressure drop can cause issues, for example with our pressure control algorithm. In some approaches, the algorithm assumes that the pressure at each nozzle is the same as the pressure measured at the center of the boom. The variable pressure drop can also affect droplet size across the boom as the pressure at each nozzle location, for instance because the droplet size is dependent on nozzle pressure. To overcome controlling the flow incorrectly in the presence of this pressure drop, a controller integrates the system efficiency, but this adds latency to the control mechanism and can affect how much variation in flow rate or droplet size occurs between locations on the boom.
The pressure drop at each location can be found through modeling known aspects of the machine configuration like the diameter(s) of the plumbing, length of the plumbing to each nozzle, types of tubing, types of restrictions or fittings along the boom, target flow rate at every nozzle location along the boom, and some characteristics about the type of liquid being dispensed. The system can experimentally validate pressure drop values on a configuration by running the system at a known flow rates at each nozzle and then measure the associated pressure drops along the boom. By modeling or characterizing the system, the system (e.g., a controller) can compensate the pressure at each nozzle to an average target pressure by controlling to an overall slightly higher pressure at the center of the machine. This pressure offset can still cause an issue with the inside nozzles having a higher than target pressure and dispensing more liquid and the outside nozzles having a lower than target pressure and dispensing slightly less liquid. The effective pressure could be calculated at each nozzle or valve, and then the system can compensate the flow rate by adjusting the duty cycle of the valves or nozzles to match their target flow rate even in the presence of the nominal pressure drop at their location.
In some approaches a sprayer for applying an agricultural product can cause skips, or areas in application coverage that do not get touched by dispensed agrochemical, for instance if the driven duty cycle of a nozzle is less than 50%. In practice, this number is 50% because nozzle tips are generally selected to overlap 50% with their neighboring nozzle and nozzles are run out of phase with one another. Many things affect the skip area like machine speed, yaw rate, application height, mixing in the air due to boom or machine turbulence or local wind conditions. The total area of the skip depends on one or more things, the effective velocity at the nozzle, the application width of the tip, and the off time of the nozzle when operating at less than 50% duty cycle.
The area can be calculated using the following formula:
In practice, we currently recommend keeping our valve (“NCV”) minimum duty cycle at or around 25% to minimize areas where skips may occur. However, the NCV can physically perform well at much lower duty cycles as the limitation in the NCV is how quickly the valve operator 400 can transition from the closed to open states or opened to close states. For instance, at 40 PSI, the NCV can open in about 7 ms and close in about 5 ms. At a frequency of 10 Hz this correlates to a minimum on-time duty cycle of about 5% and at 20 Hz, this correlates to a minimum on-time duty cycle of 10%. In general, if the frequency was increased near the minimum duty cycle range to 20 Hz it would cause the skip distance to decrease and increase our confidence at lowering the NCV minimum duty cycle threshold. In the industry, the trend is to increase the base operational frequency at all duty cycles in order to minimize skip area or distance. However, increasing the frequency causes more stress on the physical mechanics of the NCV (like the valve operator 400 and seals), and in return, lowering the frequency would lengthen the lifespan of the NCV. Increasing the frequency also causes more transitions from the open to closed and closed to open states during which the pressure in the valve varies and can cause non-linear flow or pressure drops which can affect control and target droplet size.
Therefore, being able to dynamically adjust the operational frequency of the NCV at different duty cycles and effective velocities to target a minimum skip area would be ideal for targeting an optimal life time, minimalizing inconsistencies in droplet size from the tip, or minimizing time in non-linear flow rate application periods.
Technically, the frequency at any duty cycle above 50% could be reduced to the lowest allowable frequency that still produced an acceptable coverage pattern (e.g., acceptably sized double-coverage areas). One approach to implement dynamic frequency adjustment can be that the frequency is fixed at set duty cycles and then would use a percent threshold to switch between the frequencies. This approach has the disadvantage of the fact that it doesn't use the effective nozzle velocity to minimize the skip distance, which may make it unnecessarily run at higher frequencies when it doesn't need to do so to acceptably minimize skip coverage areas.
Another way would be to have the user select a maximum skip distance and then based off that setting, each NCV could use its effective speed and off time to determine its effective skip distance and make a decision to increase or decrease the frequency to control the skip distance below the maximum entered value.
It is also worth noting that because nozzles typically run out of phase with their neighbors, frequency steps would have to happen in powers of two to ensure that nozzles could still be synced locally to one another and remain out of phase.
In alternative embodiments, the machine 1200 may operate as a standalone device or may be connected (e.g., networked) to other machines. In a networked deployment, the machine 1200 may operate in the capacity of a server machine, a client machine, or both in server-client network environments. In an example, the machine 1200 may act as a peer machine in peer-to-peer (P2P) (or other distributed) network environment. The machine 1200 may be a personal computer (PC), a tablet PC, a set-top box (STB), a personal digital assistant (PDA), a mobile telephone, a web appliance, a network router, switch or bridge, or any machine capable of executing instructions (sequential or otherwise) that specify actions to be taken by that machine. Further, while only a single machine is illustrated, the term “machine” shall also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein, such as cloud computing, software as a service (SaaS), other computer cluster configurations.
The machine (e.g., computer system) 1200 may include a hardware processor 1202 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), a main memory 1204, a static memory (e.g., memory or storage for firmware, microcode, a basic-input-output (BIOS), unified extensible firmware interface (UEFI), etc.) 1206, and mass storage 1208 (e.g., hard drive, tape drive, flash storage, or other block devices) some or all of which may communicate with each other via an interlink (e.g., bus) 1230. The machine 1200 may further include a display unit 1210, an alphanumeric input device 1212 (e.g., a keyboard), and a user interface (UI) navigation device 1214 (e.g., a mouse). In an example, the display unit 1210, input device 1212 and UI navigation device 1214 may be a touch screen display. The machine 1200 may additionally include a storage device (e.g., drive unit) 1208, a signal generation device 1218 (e.g., a speaker), a network interface device 1220, and one or more sensors 1216, such as a global positioning system (GPS) sensor, compass, accelerometer, or other sensor. The machine 1200 may include an output controller 1228, such as a serial (e.g., universal serial bus (USB), parallel, or other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) connection to communicate or control one or more peripheral devices (e.g., a printer, card reader, etc.).
Registers of the processor 1202, the main memory 1204, the static memory 1206, or the mass storage 1208 may be, or include, a machine readable medium 1222 on which is stored one or more sets of data structures or instructions 1224 (e.g., software) embodying or utilized by any one or more of the techniques or functions described herein. The instructions 1224 may also reside, completely or at least partially, within any of registers of the processor 1202, the main memory 1204, the static memory 1206, or the mass storage 1208 during execution thereof by the machine 1200. In an example, one or any combination of the hardware processor 1202, the main memory 1204, the static memory 1206, or the mass storage 1208 may constitute the machine readable media 1222. While the machine readable medium 1222 is illustrated as a single medium, the term “machine readable medium” may include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) configured to store the one or more instructions 1224.
The term “machine readable medium” may include any medium that is capable of storing, encoding, or carrying instructions for execution by the machine 1200 and that cause the machine 1200 to perform any one or more of the techniques of the present disclosure, or that is capable of storing, encoding or carrying data structures used by or associated with such instructions. Non-limiting machine readable medium examples may include solid-state memories, optical media, magnetic media, and signals (e.g., radio frequency signals, other photon based signals, sound signals, etc.). In an example, a non-transitory machine readable medium comprises a machine readable medium with a plurality of particles having invariant (e.g., rest) mass, and thus are compositions of matter. Accordingly, non-transitory machine-readable media are machine readable media that do not include transitory propagating signals. Specific examples of non-transitory machine readable media may include: non-volatile memory, such as semiconductor memory devices (e.g., Electrically Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM)) and flash memory devices; magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks.
The instructions 1224 may be further transmitted or received over a communications network 1226 using a transmission medium via the network interface device 1220 utilizing any one of a number of transfer protocols (e.g., frame relay, internet protocol (IP), transmission control protocol (TCP), user datagram protocol (UDP), hypertext transfer protocol (HTTP), etc.). Example communication networks may include a local area network (LAN), a wide area network (WAN), a packet data network (e.g., the Internet), mobile telephone networks (e.g., cellular networks), Plain Old Telephone (POTS) networks, and wireless data networks (e.g., Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards known as Wi-Fi®, IEEE 802.16 family of standards known as WiMax®), IEEE 802.15.4 family of standards, peer-to-peer (P2P) networks, among others. In an example, the network interface device 1220 may include one or more physical jacks (e.g., Ethernet, coaxial, or phone jacks) or one or more antennas to connect to the communications network 1226. In an example, the network interface device 1220 may include a plurality of antennas to wirelessly communicate using at least one of single-input multiple-output (SIMO), multiple-input multiple-output (MIMO), or multiple-input single-output (MISO) techniques. The term “transmission medium” shall be taken to include any intangible medium that is capable of storing, encoding or carrying instructions for execution by the machine 1200, and includes digital or analog communications signals or other intangible medium to facilitate communication of such software. A transmission medium is a machine readable medium.
In an example, the controller 1302 is in communication with one or more of the nozzle control systems 600. For instance, the system 1300 includes a first nozzle control system 600A, a second nozzle control system 600B, and a third nozzle control system 600C. The first system 600A includes a first valve 304A having a first coil 420A. The second system 600B includes a second valve 304B having a second coil 420B. The third system 600C includes a third valve 304C having a third coil 420C. The controller 1302 modulates the valves 304 according to one or more duty cycles. For example, the controller 1302 is in communication with the first system 600A and energizes the coil 420A, for instance according to a first specified duty cycle and a first magnetic flux correction. The controller 1302 is in communication with the second system 600B and energizes the coil 420B, for instance according to a second specified duty cycle and a second magnetic flux correction. The controller 1302 is in communication with the third system 600C and energizes the coil 420C, for instance according to a third specified duty cycle and a third magnetic flux correction. Accordingly, the controller 1302 operates the valves 304.
In some examples, the controller 1302 facilitates modulation of one or more of the valves 304 out of phase with each other, for instance to conserve power usage by the system 1300. For example, the first valve 304A is modulated out of phase with the second valve 304B. The first valve 304A is modulated out of phase with the third valve 304C. Accordingly, the first valve 304A is modulated out of phase with one or more of the second valve 304B or the third valve 304C. In another example, the second valve 304B is operated in phase with the third valve 304C. The first valve 304A is modulated out of phase with the second valve 304B and the third valve 304C (with the valves 304B, 304C modulated in phase with each other). Accordingly, modulation of the valves 304 out of phase with each other reduces the number of valves 304 that are drawing power simultaneously within the system 1300.
In an example, the controller 1302 modulates the first valve 304A out of phase with the second valve 304B at a specified phase. The controller 1302 operates the valve 304A, for example by operating a moveable valve operator (e.g., valve operator 400, shown in
Aspect 1 is a system for applying an agricultural product, the system comprising: a valve including a solenoid, the valve including: a coil configured to generate a magnetic flux; a moveable valve operator configured to translate with respect to the coil based on the magnetic flux, wherein the valve operator translates between a closed position and an open position according to a specified magnetic flux associated with a specified duty cycle, wherein: in the closed position, the valve operator is configured to prevent flow through the valve; and in the open position, the valve operator is configured to permit flow through the valve; a dissipation element having a dissipation characteristic and configured to dissipate energy from the coil; and a valve controller, including processing circuitry configured to: measure one or more electrical characteristics of at least one of the coil or the dissipation element; determine an actual duty cycle of the valve operator using the measured electrical characteristics; determine a magnetic flux correction based on a difference between the actual duty cycle and the specified duty cycle; and operate the valve operator according to the specified magnetic flux and the magnetic flux correction to guide the actual duty cycle toward the specified duty cycle.
In Aspect 2, the subject matter of Aspect 1 optionally includes wherein determining actual duty cycle of the valve operator using the measured electrical characteristics includes: comparing the electrical characteristics to a valve operator translation signature to determine a translation start time and a translation stop time of the valve operator; and determining the difference between the translation start time and the translation stop time.
In Aspect 3, the subject matter of Aspect 2 optionally includes wherein the valve operator translation signature includes a characteristic change threshold, and comparing the electrical characteristics to the valve operator translation signature includes: determining a change in the electrical characteristics; comparing the change in the electrical characteristics to the electrical characteristic change threshold; and wherein the controller records one or more of the translation start time and the translation stop time based on the comparison of the change in the electrical characteristics to the electrical characteristic change threshold.
In Aspect 4, the subject matter of Aspect 3 optionally includes wherein electrical characteristic change threshold is a current threshold, and the controller records the translation start time when a change in a coil current of the coil exceeds the current threshold.
In Aspect 5, the subject matter of any one or more of Aspects 3-4 optionally include wherein the electrical characteristic change threshold is a voltage threshold, and the controller records the translation stop time when a change in a dissipation element voltage of the dissipation element exceeds the voltage threshold.
In Aspect 6, the subject matter of any one or more of Aspects 2-5 optionally include wherein the valve operator translation signature includes: a characteristic change threshold; a first characteristic inflection where a current of the coil decreases; a second characteristic inflection where the current of the coil increases, and wherein the controller records one or more of the translation start time and the translation stop time when the difference between the current of the coil at the first characteristic inflection and the current of the coil at the second characteristic inflection exceeds the characteristic change threshold.
In Aspect 7, the subject matter of any one or more of Aspects 2-6 optionally include wherein the valve operator translation signature includes: a characteristic change threshold; a first characteristic inflection where a voltage of the dissipation element increases; a second characteristic inflection where the voltage of the dissipation element decreases, and wherein the controller records one or more of the translation start time and the translation stop time when the difference between the voltage of the dissipation element at the first characteristic inflection and the voltage of the dissipation element at the second characteristic inflection exceeds the characteristic change threshold.
In Aspect 8, the subject matter of any one or more of Aspects 2-7 optionally include wherein the valve operator translation signature includes: a characteristic change threshold; a first characteristic inflection where a voltage of the dissipation element increases; a second characteristic inflection where the voltage of the dissipation element decreases, and wherein the controller records one or more of the translation start time and the translation stop time when the voltage of the dissipation element changes at a rate greater than the characteristic change threshold.
In Aspect 9, the subject matter of any one or more of Aspects 1-8 optionally include wherein the coil electrical characteristics include one or more of a coil current or a coil voltage.
In Aspect 10, the subject matter of any one or more of Aspects 1-9 optionally include wherein the dissipation element electrical characteristics include one or more of a dissipation element current or a dissipation element voltage.
In Aspect 11, the subject matter of any one or more of Aspects 1-10 optionally include wherein: the coil generates the magnetic flux in response to a coil control signal generated by the controller; and the specified duty cycle corresponds to a difference between a first time interval when the controller begins generating the coil control signal and a second time interval when the controller stops generating the coil control signal.
In Aspect 12, the subject matter of any one or more of Aspects 1-11 optionally include wherein: the coil generates the magnetic flux in response to a coil control signal generated by the controller; and the controller is configured to modulate the coil control signal when the valve operator is located in the open position.
In Aspect 13, the subject matter of any one or more of Aspects 1-12 optionally include wherein moveable valve operator includes a poppet.
In Aspect 14, the subject matter of any one or more of Aspects 1-13 optionally include wherein: the valve operator is biased toward the closed position; and the magnetic flux generated by the coil is configured to overcome the bias of the valve operator to translate the valve operator from closed position to the open position.
In Aspect 15, the subject matter of any one or more of Aspects 1-14 optionally include wherein: the valve operator is biased toward the open position; and the magnetic flux generated by the coil is configured to overcome the bias of the valve operator to translate the valve operator from open position to the closed position.
In Aspect 16, the subject matter of any one or more of Aspects 1-15 optionally include wherein operating the valve operator according to the specified magnetic flux includes operating the valve operator with an electrical signal corresponding to the specified magnetic flux.
In Aspect 17, the subject matter of any one or more of Aspects 1-16 optionally include a frame configured to concentrate the magnetic flux on the moveable valve operator.
In Aspect 18, the subject matter of any one or more of Aspects 1-17 optionally include wherein the dissipation element is a TVS diode.
Aspect 19 is a system for applying an agricultural product, the system comprising: a first valve including a first solenoid, the valve including: a first coil configured to generate a magnetic flux; a first moveable valve operator configured to translate with respect to the coil based on the magnetic flux, wherein the valve operator translates between a closed position and an open position according to a specified magnetic flux associated with a specified duty cycle, wherein: in the closed position, the valve operator is configured to prevent flow through the valve; and in the open position, the valve operator is configured to permit flow through the valve; a second valve including a second solenoid, a second coil, and a second moveable operator; a dissipation element having a dissipation characteristic and configured to dissipate energy from the coil; and a valve controller, including processing circuitry configured to: measure one or more electrical characteristics of at least one of the first coil, the second coil, or the dissipation element; determine an actual duty cycle of one or more of the first valve operator or the second valve operator using the measured electrical characteristics; determine a magnetic flux correction based on a difference between the actual duty cycle and the specified duty cycle; and operate one or more of the first or second valve operators according to the specified magnetic flux and the magnetic flux correction to guide the actual duty cycle toward the specified duty cycle.
Aspect 20 is a system for applying an agricultural product, the system comprising: a first valve including a first solenoid, the valve including: a first coil configured to generate a magnetic flux; a first moveable valve operator configured to translate with respect to the coil based on the magnetic flux, wherein the valve operator translates between a closed position and an open position according to a specified magnetic flux associated with a specified duty cycle, wherein: in the closed position, the valve operator is configured to prevent flow through the valve; and in the open position, the valve operator is configured to permit flow through the valve; a second valve including a second solenoid, a second coil, and a second moveable operator; a dissipation element having a dissipation characteristic and configured to dissipate energy from one or more of the first coil or the second coil; and a valve controller, including processing circuitry configured to: measure one or more electrical characteristics of at least one of the first coil, the second coil, or the dissipation element; determine an actual duty cycle of one or more of the first valve operator or the second valve operator using the measured electrical characteristics; determine a magnetic flux correction based on a difference between the actual duty cycle and the specified duty cycle; and wherein the first valve is modulated out of phase with the second valve at a specified phase and the controller operates the first moveable valve operator according to the specified magnetic flux and the magnetic flux correction to guide an actual phase of one or more of the first valve or the second valve toward the specified phase.
Aspect 21 may include or use, or may optionally be combined with any portion or combination of any portions of any one or more of Aspects 1 through 20 to include or use, subject matter that may include means for performing any one or more of the functions of Aspects 1 through 20, or a machine-readable medium including instructions that, when performed by a machine, cause the machine to perform any one or more of the functions of Aspects 1 through 20.
The above description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention can be practiced. These embodiments are also referred to herein as “examples.” Such examples can include elements in addition to those shown or described. However, the present inventors also contemplate examples in which only those elements shown or described are provided. Moreover, the present inventors also contemplate examples using any combination or permutation of those elements shown or described (or one or more aspects thereof), either with respect to a particular example (or one or more aspects thereof), or with respect to other examples (or one or more aspects thereof) shown or described herein.
In the event of inconsistent usages between this document and any documents so incorporated by reference, the usage in this document controls.
In this document, the terms “a” or “an” are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” In this document, the term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated. In this document, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended, that is, a system, device, article, composition, formulation, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.
Geometric terms, such as “parallel”, “perpendicular”, “round”, or “square”, are not intended to require absolute mathematical precision, unless the context indicates otherwise. Instead, such geometric terms allow for variations due to manufacturing or equivalent functions. For example, if an element is described as “round” or “generally round,” a component that is not precisely circular (e.g., one that is slightly oblong or is a many-sided polygon) is still encompassed by this description.
Method examples described herein can be machine or computer-implemented at least in part. Some examples can include a computer-readable medium or machine-readable medium encoded with instructions operable to configure an electronic device to perform methods as described in the above examples. An implementation of such methods can include code, such as microcode, assembly language code, a higher-level language code, or the like. Such code can include computer readable instructions for performing various methods. The code may form portions of computer program products. Further, in an example, the code can be tangibly stored on one or more volatile, non-transitory, or non-volatile tangible computer-readable media, such as during execution or at other times. Examples of these tangible computer-readable media can include, but are not limited to, hard disks, removable magnetic disks, removable optical disks (e.g., compact disks and digital video disks), magnetic cassettes, memory cards or sticks, random access memories (RAMs), read only memories (ROMs), and the like.
The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to comply with 37 C.F.R. § 1.72 (b), to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description as examples or embodiments, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
This patent application is a continuation of U.S. patent application Ser. No. 17/465,644, filed Sep. 2, 2021, which application is a continuation of U.S. patent application Ser. No. 17/001,539, filed Aug. 24, 2020, issued on Feb. 1, 2022 as U.S. Pat. No. 11,236,841, which claims the benefit of priority of Krosschell et al. U.S. Provisional Patent Application Ser. No. 62/911,045, entitled “VALVE CONTROL SYSTEM AND METHOD,” filed on Oct. 4, 2019 (Attorney Docket No. 2754.276PRV), all of which are hereby incorporated by reference herein in their entireties.
| Number | Date | Country | |
|---|---|---|---|
| 62911045 | Oct 2019 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17465644 | Sep 2021 | US |
| Child | 18750201 | US | |
| Parent | 17001539 | Aug 2020 | US |
| Child | 17465644 | US |
