Patent Description:
<CIT> discloses a control system for controlling the down pressure applied to a soil-engaging component of an agricultural implement. A down pressure actuator is coupled to the soil-engaging component. An energy storage device and a piston-containing cylinder are coupled to each other by a system containing pressurized fluid. A check valve is coupled between the energy storage device and the down pressure actuator to control the flow of the pressurized fluid from the energy storage device to the cylinder. A controllable relief valve and variable orifice (<NUM>) are coupled between the down pressure actuator and the energy storage device to control the flow of the pressurized fluid from the cylinder to the energy storage device. A controller supplies control signals to the relief valve and variable orifice based on the output signal of a pressure sensor corresponding to the pressure of the pressurized fluid.

<CIT> describes systems, methods and apparatus for monitoring soil properties, including soil moisture and soil temperature, during an agricultural input application. Embodiments include a soil moisture sensor and/or a soil temperature sensor mounted to a seed firmer for measuring moisture and temperature in a planting trench. Additionally, systems, methods and apparatus are provided for adjusting depth based on the monitored soil properties.

The solution to the technical problem is achieved by the subject-matter of independent claims <NUM> and <NUM>, defining per se the invention. Particular embodiments of the invention are defined in the dependent claims.

The foregoing and additional aspects and implementations of the present disclosure will be apparent to those of ordinary skill in the art in view of the detailed description of various embodiments and/or implementations, which is made with reference to the drawings, a brief description of which is provided next.

The invention may best be understood by reference to the following description taken in conjunction with the accompanying drawings.

Specific embodiments have been shown by way of example in the drawings and will be described in detail herein.

Although the invention will be described in connection with certain preferred embodiments, it will be understood that the invention is not limited to those particular embodiments. On the contrary, the invention is intended to be covered by the scope of the invention as defined by the appended claims.

An agricultural planter typically includes a number of individual row units, each of which includes its own row cleaner device, row opener device and row closing device. The down pressure is typically controlled separately for each row unit or each of several groups of row units, and is preferably controlled separately for one or more of the individual devices in each row unit, as described in more detail in pending <CIT>.

<FIG> illustrate an improved gauge wheel load sensor that takes the upward force from a pivoting planter gauge wheel support, such as the pivoting support arms <NUM> in the row unit equipment shown in <FIG> and <FIG>, and translates that force into a fluid pressure in a fluid chamber <NUM>. The gauge wheel support arms push against an equalizer support <NUM>, which is connected to a slider <NUM> that slides along an arcuate guide <NUM>. Movement of the slider along the guide <NUM> moves one end of a connector arm <NUM> that is attached at its other end to a rocker arm <NUM> mounted for pivoting movement abound a stationary pivot pin <NUM>. The lower end of the rocker arm <NUM> engages a ram <NUM> in a hydraulic cylinder <NUM> that is filled with a pressurized hydraulic fluid.

Depth adjustment is accomplished in the conventional sense by pivoting the assembly around a pivot <NUM>, and locking a handle <NUM> into the desired position with a mechanism <NUM>. With this design it is preferred that that there is no air trapped in the fluid chamber <NUM>. For this reason, the mechanism includes a bleed valve <NUM>. The process for removal of air is to extend the ram to the maximum extent with calibration/travel limiter plates <NUM> (<FIG>) removed. The system is then filled completely with fluid with the bleed valve <NUM> closed. Then the bleed valve <NUM> is opened, and the rocker arm <NUM> is pushed against the ram <NUM> to move the ram to the exact place where the calibration/travel limit plates <NUM> allow a calibration plate retaining screw <NUM> to fit into a hole. This ensures that each assembly is set the same so all the row units of the planter are at the same depth. At this point the bleed valve <NUM> is closed. With all air removed, the mechanical/fluid system will act as a rigid member against forces in compression. The travel limiter plate <NUM> keeps a cam pivot weldment from falling down when the planter is lifted off the ground.

Standard industry practice is to use a strain gauge to directly measure the planter gauge wheel load. The design shown in <FIG> is an improvement over the state of the art because it allows the sensor to measure only the down force on the gauge wheels. In typical designs using strain gauge type sensors, the mechanical linkage that allows the gauge wheels to oscillate causes the measured wheel force to have substantial noise due to changes in the force being applied. For this reason, it can be difficult to determine which parts of the signal correspond to actual changes in down force on the gauge wheels, versus signal changes that are due to movement of components of the gauge wheel support mechanism. The reason for this is that strain gauge sensors will only measure the force that is being applied in a single plane. Because of the linkage and pivot assembly that is used on typical planters, the force being applied to the strain gauge type designs can change based on the depth setting or whether the planter gauge wheels are oscillating over terrain. In this way they will tend to falsely register changes in gauge wheel down force and make it difficult to have a closed loop down pressure response remain consistent.

The fluid seal of the pressure sensor described here creates friction in the system which has the effect of damping out high frequency noise. Agricultural fields have very small scale variations in the surface which cause noise to be produced in the typical down force sensor apparatus. By using fluid pressure this invention decouples the sensor from the mechanical linkage and allows the true gauge wheel force to be more accurately measured. Lowering the amount of systematic noise in the gauge wheel load output sensor makes it easier to produce an automatic control system that accurately responds to true changes in the hardness of the soil, as opposed to perceived changes in soil hardness due to noise induced on the sensor.

<FIG> is a schematic diagram of a hydraulic control system for any or all of the hydraulic actuators in a down pressure control system. The hydraulic cylinder <NUM> is supplied with pressurized hydraulic fluid from a source <NUM> via a first controllable two-position control valve <NUM>, a restriction <NUM> and a check valve <NUM>. The pressurized hydraulic fluid supplied to the cylinder <NUM> can be returned from the cylinder to a sump <NUM> via a second controllable two-position control valve <NUM>, a restriction <NUM> and a check valve <NUM>. Both the control valves <NUM> and <NUM> are normally closed, but can be opened by energizing respective actuators <NUM> and <NUM>, such as solenoids. Electrical signals for energizing the actuators <NUM> and <NUM> are supplied to the respective actuators via lines <NUM> and <NUM> from a controller <NUM>, which in turn may be controlled by a central processor <NUM>. The controller <NUM> receives input signals from a plurality of sensors, which in the example of <FIG> includes a pressure transducer <NUM> coupled to the hydraulic cylinder <NUM> via line <NUM>, and a ground hardness sensor <NUM>. An accumulator <NUM> is also coupled to the hydraulic cylinder <NUM>, and a relief valve <NUM> connects the hydraulic cylinder <NUM> to the sump <NUM> in response to an increase in the pressure in the cylinder <NUM> above a predetermined level.

To reduce the energy required from the limited energy source(s) available from the tractor or other propulsion device used to transport the row units over an agricultural field, the control valves <NUM> and <NUM> are preferably controlled with a pulse width modulation (PWM) control system implemented in the controller <NUM>. The PWM control system supplies short-duration (e.g., in the range of <NUM> milliseconds to <NUM> seconds with orifice sizes in the range of <NUM> to. <NUM> inch) pulses to the actuators <NUM> and <NUM> of the respective control valves <NUM> and <NUM> to open the respective valves for short intervals corresponding to the widths of the PWM pulses. This significantly reduces the energy required to increase or decrease the pressure in the hydraulic cylinder <NUM>. The pressure on the exit side of the control valve is determined by the widths of the individual pulses and the number of pulses supplied to the control valves <NUM> and <NUM>. Thus, the pressure applied to the hydraulic cylinder <NUM> may be controlled by separately adjusting the two control valves <NUM> and <NUM> by changing the width and/or the frequency of the electrical pulses supplied to the respective actuators <NUM> and <NUM>, by the controller <NUM>. This avoids the need for a constant supply current, which is a significant advantage when the only available power source is located on the tractor or other vehicle that propels the soil-engaging implement(s) across a field.

The hydraulic control system of <FIG> may be used to control multiple hydraulic cylinders on a single row unit or a group of row units, or may be replicated for each individual hydraulic cylinder on a row unit having multiple hydraulic cylinders. For example, in the system described above having a ground hardness sensor located out in front of the clearing wheels, it is desirable to have each hydraulic cylinder on any given row unit separately controlled so that the down pressure on each tool can be adjusted according to the location of that tool in the direction of travel. Thus, when the ground hardness sensor detects a region where the soil is softer because it is wet, the down pressure on each tool is preferably adjusted to accommodate the softer soil only during the time interval when that particular tool is traversing the wet area, and this time interval is different for each tool when the tools are spaced from each other in the direction of travel. In the case of a group of row units having multiple hydraulic cylinders on each row unit, the same hydraulic control system may control a group of valves having common functions on all the row units in a group.

<FIG> is a schematic diagram of a modified hydraulic control system that uses a single three-position control valve <NUM> in place of the two two-position control valves and the two check valves used in the system of <FIG>. The centered position of the valve <NUM> is the closed position, which is the normal position of this valve. The valve <NUM> has two actuators 2620a and 2620b, one of which moves the valve to a first open position that connects a source <NUM> of pressurized hydraulic fluid to a hydraulic cylinder <NUM> via restriction 2620c, and the other of which moves the valve to a second open position that connects the hydraulic cylinder <NUM> to a sump <NUM>. Electrical signals for energizing the actuators 2620a and 2620b are supplied to the respective actuators via lines <NUM> and <NUM> from a controller <NUM>, which in turn may be controlled by a central processor <NUM>. The controller <NUM> receives input signals from a pressure transducer <NUM> coupled to the hydraulic cylinder <NUM> via line <NUM>, and from an auxiliary sensor <NUM>, such as a ground hardness sensor. An accumulator <NUM> is coupled to the hydraulic cylinder <NUM>, and a relief valve <NUM> connects the hydraulic cylinder <NUM> to the sump <NUM> in response to an increase in the pressure in the cylinder <NUM> above a predetermined level.

As depicted in <FIG>, a PWM control system supplies short-duration pulses P to the actuators 2620a and 2620b of the control valve <NUM> to move the valve to either of its two open positions for short intervals corresponding to the widths of the PWM pulses. This significantly reduces the energy required to increase or decrease the pressure in the hydraulic cylinder <NUM>. In <FIG>, pulses P1-P3, having a voltage level V1, are supplied to the actuator 2620b when it is desired to increase the hydraulic pressure supplied to the hydraulic cylinder <NUM>. The first pulse P1 has a width T1 which is shorter than the width of pulses P2 and P3, so that the pressure increase is smaller than the increase that would be produced if P1 had the same width as pulses P2 and P3. Pulses P4-P6, which have a voltage level V2, are supplied to the actuator 2620a when it is desired to decrease the hydraulic pressure supplied to the hydraulic cylinder <NUM>. The first pulse P4 has a width that is shorter than the width T2 of pulses P2 and P3, so that the pressure decrease is smaller than the decrease that would be produced if P4 had the same width as pulses P5 and P6. When no pulses are supplied to either of the two actuators 2620a and 2620b, as in the "no change" interval in <FIG>, the hydraulic pressure remains substantially constant in the hydraulic cylinder <NUM>.

<FIG> illustrate a modified gauge wheel load sensor that includes an integrated accumulator <NUM>. The purpose of the accumulator <NUM> is to damp pressure spikes in the sensor when the planter is operating at low gauge wheel loads. When the forces that the gauge wheel support arms <NUM> are exerting on the hydraulic ram <NUM> are near zero, it is more common for the surface of the soil or plant residue to create pressure spikes that are large in relation to the desired system sensor pressure. These pressure spikes produce corresponding changes in the vertical position (elevation) of the gauge wheels. As the target gauge wheel down force increases, and consequently the pressure in the fluid chamber <NUM> and the transducer output voltage from sensor <NUM>, the small spikes of pressure due to variations in the soil surface or plant residue decrease proportionally.

In the present system, rather than have a perfectly rigid fluid coupling between the ram <NUM> and the pressure transducer <NUM>, as load increases on the ram <NUM>, the fluid first pushes against a piston <NUM> of the accumulator <NUM> that is threaded into a side cavity <NUM> in the same housing that forms the main cavity for the ram <NUM>. The increased pressure compresses an accumulator spring <NUM> until the piston <NUM> rests fully against a shoulder on the interior wall of the accumulator housing <NUM>, thus limiting the retracting movement of the accumulator piston <NUM>. At this point, the system becomes perfectly rigid. The amount of motion permitted for the accumulator piston <NUM> must be very small so that it does not allow the depth of the gauge wheel setting to fluctuate substantially. The piston accumulator (or other energy storage device) allows the amount of high frequency noise in the system to be reduced at low gauge-wheel loads. Ideally an automatic down pressure control system for an agricultural planter should maintain a down pressure that is as low as possible to avoid over compaction of soil around the area of the seed, which can inhibit plant growth. However, the performance of most systems degrades as the gauge wheel load becomes close to zero, because the amount of latent noise produced from variation in the field surface is large in relation to the desired gauge wheel load.

Planter row units typically have a gauge wheel equalizer arm <NUM> that is a single unitary piece. It has been observed that the friction between the equalizer arm <NUM> and the gauge wheel support arms <NUM>, as the gauge wheel <NUM> oscillates up and down, can generate a substantial amount of noise in the sensor. At different adjustment positions, the edges of the equalizer arm <NUM> contact the support arms <NUM> at different orientations and can bite into the surface and prevent forces from being smoothly transferred as they increase and decrease. When the equalizer arm <NUM> is a single unitary piece, there is necessarily a high amount of friction that manifests itself as signal noise in the sensor. This signal noise makes it difficult to control the down pressure system, especially at low levels of gauge wheel load.

To alleviate this situation, the equalizer arm <NUM> illustrated in <FIG> has a pair of contact rollers <NUM> and <NUM> are mounted on opposite ends of the equalizer arm. These rollers <NUM> and <NUM> become the interface between the equalizer arm and the support arms <NUM>, allowing forces to be smoothly transferred between the support arms <NUM> and the equalizer arm <NUM>. The roller system allows the gauge wheel support arms <NUM> to oscillate relative to each other without producing any sliding friction between the support arms <NUM> and the equalizer arm <NUM>. This significantly reduces the friction that manifests itself as signal noise in the sensor output, which makes it difficult to control the down pressure control system, especially at low levels of gauge wheel load.

<FIG> is a longitudinal section through the device of <FIG>, with the addition of a rocker arm <NUM> that engages a ram <NUM> that controls the fluid pressure within a cylinder <NUM>. A fluid chamber <NUM> ladjacent the inner end of the ram <NUM> opens into a lateral cavity that contains a pressure transducer <NUM> that produces an electrical output signal representing the magnitude of the fluid pressure in the fluid chamber <NUM>. The opposite end of the cylinder <NUM> includes an accumulator <NUM> similar to the accumulator <NUM> included in the device of <FIG> described above. Between the fluid chamber <NUM> and the accumulator <NUM>, a pair of valves <NUM> and <NUM> are provided in parallel passages158 and <NUM> extending between the chamber <NUM> and the accumulator <NUM>. The valve <NUM> is a relief valve that allows the pressurized fluid to flow from the chamber <NUM> to the accumulator <NUM> when the ram <NUM> advances farther into the chamber <NUM>. The valve <NUM> is a check valve that allows pressurized fluid to flow from the accumulator <NUM> to the chamber <NUM> when the ram <NUM> moves outwardly to enlarge the chamber <NUM>. The valves <NUM> and <NUM> provide overload protection (e.g., when one of the gauge wheels hits a rock) and to ensure that the gauge wheels retain their elevation setting.

<FIG> illustrate a modified sensor arrangement for a pair of gauge wheels <NUM> and <NUM> rolling on opposite sides of a furrow <NUM>. The two gauge wheels are independently mounted on support arms <NUM> and <NUM> connected to respective rams <NUM> and <NUM> that control the fluid pressure in a pair of cylinders <NUM> and <NUM>. A hydraulic hose <NUM> connects the fluid chambers of the respective cylinders <NUM> and <NUM> to each other and to a common pressure transducer <NUM>, which produces an electrical output signal corresponding to the fluid pressure in the hose <NUM>. The output signal is supplied to an electrical controller that uses that signal to control the down forces applied to the two gauge wheels <NUM> and <NUM>. It will be noted that the two gauge wheels can move up and down independently of each other, so the fluid pressure sensed by the transducer <NUM> will be changed by vertical movement of either or both of the gauge wheels <NUM> and <NUM>.

<FIG> illustrate electrical/hydraulic control systems that can be used to control a down-pressure actuator <NUM> in response to the electrical signal provided to a controller <NUM> by a pressure transducer <NUM>. In each system the transducer <NUM> produces an output signal that changes in proportion to changes in the fluid pressure in a cylinder <NUM> as the position of a ram <NUM> changes inside the cylinder <NUM>. In <FIG>, the pressurized fluid chamber in the cylinder <NUM> is coupled to an accumulator <NUM> by a relief valve <NUM> to allow pressurized fluid to flow to the accumulator, and by a check valve <NUM> to allow return flow of pressurized fluid from the accumulator to the cylinder <NUM>. In <FIG>, the accumulator <NUM> is replaced with a pressurized fluid source <NUM> connected to the check valve <NUM>, and a sump <NUM> connected to the relief valve <NUM>. In <FIG>, the accumulator <NUM> is connected directly to the pressurized fluid chamber in the cylinder <NUM>, without any intervening valves. In the system of <FIG>, there is no accumulator, and the pressure sensor <NUM> is connected directly to the pressurized fluid chamber in the cylinder <NUM>.

<FIG> illustrates a modified electrical/hydraulic control system for controlling a down-pressure actuator <NUM> in response to an electrical signal provided to a controller <NUM> by a pressure transducer <NUM>. The transducer <NUM> produces an output signal that changes in proportion to changes in the fluid pressure in a cylinder <NUM> as the position of a ram <NUM> changes inside the cylinder <NUM>. Thus the ram <NUM> functions as a gauge wheel sensor. The pressurized fluid chamber in the cylinder <NUM> is coupled to an accumulator <NUM> by a controllable valve <NUM> to allow pressurized fluid to flow to the accumulator <NUM> through a controllable variable orifice <NUM>, and by a check valve <NUM> to allow return flow of pressurized fluid from the accumulator <NUM> to the cylinder <NUM>.

When the force applied to the piston <NUM>, e.g., by the rocker arm <NUM>, increases when the ground-engaging implement encounters harder ground or strikes a rock, the piston <NUM> is moved to the left. This causes a portion of the pressurized fluid to flow through the variable orifice <NUM> and the relief valve <NUM> to the accumulator <NUM>. Both the variable orifice <NUM> and the relief valve <NUM> are controlled by electrical control signals from the controller <NUM>, which receives the output signal from the pressure sensor <NUM>.

The variable orifice <NUM> acts as an adjustable and controllable damper affecting the stiffness of, for example, a planter gauge wheel suspension. Also, the electro-proportional relief valve <NUM> allows the stiffness of, for example, a planter row unit ride to be changed dynamically. For example, the controller <NUM> can be programmed to allow a stiffer setting or higher relief pressure in smooth fields. In rougher fields, the relief pressure can be reduced to allow more travel of the gauge wheels relative to the opener disks. This results in less bouncing of the row unit. The amount of variation in the pressure sensor output signal reflects variations in the roughness of the field. The controller can use this variation or smoothness of the pressure signal over time to control the relief pressure in real time.

When the force applied to the piston is reduced, the fluid pressure within the cylinder <NUM> is reduced, and the accumulator causes a portion of the fluid to flow back into the cylinder <NUM> via the check valve <NUM>. The reduced pressure is sensed by the pressure sensor <NUM>, which produces a corresponding change in the sensor output signal supplied to the controller <NUM>.

The controller <NUM> is programmed with an algorithm represented by the flow chart in <FIG>. The first step <NUM> selects a predetermined system "mapping" of variables such as the diameter of the variable orifice <NUM> and relief pressure in the cylinder <NUM>. Other variables such as the down pressure control system set point can be included in the mapping. The mapping is based on tillage and soil conditions that lead to typical characteristics in the sensor data. After the mapping of the selected variables, a field operation such as planting, fertilizing or tillage, is started at step <NUM>, and at step <NUM> the pressure transducer <NUM> supplies the controller <NUM> with a signal that varies with the fluid pressure in the cylinder <NUM>, which corresponds to changes in the gauge wheel load. The controller <NUM> computes a running average value of the gauge wheel load for a selected time period at step <NUM>, and at step <NUM> supplies a control signal to the down-pressure actuator <NUM> to control the down pressure in a closed loop.

In parallel with the closed loop control of the down-pressure actuator <NUM>, the controller also adjusts the values of the mapped variables in steps <NUM>-<NUM>. Step <NUM> performs a statistical analysis of the gauge wheel sensor values to determine the signal-to-noise ratio ("SNR"), of the level of the desired signal to the level of background noise in the gauge wheel down pressure signal. The SNR can be determined by any of the known standard procedures, such as determining the ratio of the arithmetic mean to the standard deviation. The controller then determines whether the current SNR is above or below a preselected value, at steps <NUM> and <NUM>. If the SNR is determined to be above the preselected value at step <NUM>, step <NUM> adjusts the mapped values to reduce the target set point and the orifice diameter and to increase the relief pressure. If the SNR is below the preselected value at step <NUM>, step <NUM> adjusts the mapped values to increase the target set point and the orifice diameter and to decrease the relief pressure.

<FIG> illustrates a modified control system in which the relief valve <NUM> is replaced with a controllable <NUM>-way valve <NUM>, and a sump <NUM> and a pressure supply pump <NUM> are connected to the valve <NUM>. This control system also includes a position sensor <NUM>, such as an inductive sensor or a linear encoder, which supplies the controller <NUM> with a signal representing the position of the piston <NUM> within the cylinder <NUM>. The signal from the position sensor <NUM> enables the controller <NUM> to identify in real time the depth of the opener relative to the gauge wheel.

When the <NUM>-way valve <NUM> is in its center position, as shown in <FIG>, the cylinder <NUM> is disconnected from both the sump <NUM> and the pump <NUM>, and thus the cylinder <NUM> is coupled to the accumulator <NUM> via the variable orifice <NUM>. This is the normal operating position of the valve <NUM>. When the controller <NUM> produces a signal that moves the valve <NUM> to the right, the valve connects the cylinder <NUM> to the pressure supply pump <NUM> to increase the fluid pressure in the cylinder <NUM> to a desired level. When the controller <NUM> produces a signal that moves the valve <NUM> to the left, the valve connects the cylinder <NUM> to the sump <NUM> to relieve excessive pressure in the cylinder <NUM>.

The system in <FIG> allows active control of the depth of the ground-engaging element by using the pressure control valve <NUM> to change the pressure in the cylinder <NUM>. Because the piston <NUM> is connected to the gauge wheel arms via the rocker, the gauge wheels move relative to the opener disks as the piston <NUM> moves in and out.

When planting an agricultural field with seeds, it is important to control the planting depth in real time as the planting machine traverses the field, because it is critical that the seeds all be planted into moisture so that each seed emerges from the soil at the same time. The depth of the seed can be changed based on some type of moisture sensor system, or even based on a satellite or drone system that is able to detect changes in the soil chemistry that would make it desirable to change the depth of the planted seed in different areas of the field.

<FIG> illustrates a modified system that enables the operator to select a desired planting depth setting, and then automatically maintains the actual planting depth within a selected range above and below the selected depth. In this system, a fluid chamber <NUM> includes a fluid port <NUM> (see <FIG> and <FIG>) that is connected to one or more valves to allow hydraulic fluid to be added to or removed from the chamber <NUM> to change the angle of the opener disc relative to the gauge wheel. A distance sensor <NUM> produces an output signal representing the position of the opener disc support arm along the arcuate guide, which changes as the angle between the two support arm changes with changes in the depth of the opener disc relative to the elevation of the gauge wheel (the soil surface). The output signal from the distance sensor <NUM> will be referred to as the "seed depth" signal because the depth of the opener disc determines the depth of the furrow in which the seed is planted.

In one embodiment that provides both environmental protection and low cost, a pair of valves are controlled to open and close to extend or retract the ram of a hydraulic cylinder to move a slider/depth adjuster to the desired position. If the position of the slider/depth adjuster falls out of tolerance, the system automatically opens and closes the valve to maintain the correct setting. Each row unit may be provided with its own valves and associated control system. This design may use a small hydraulic ram <NUM> to perform what would typically be a manual depth adjustment. The ram <NUM> pushes on a rocker arm <NUM>, which is connected to a link arm <NUM>, which is connected to a slider piece <NUM>. The slider piece <NUM> is connected to the planter row unit depth adjustment handle and is free to move throughout the same adjustment range that the handle could be moved manually to effect a depth adjustment.

The pressure inside the chamber <NUM> is equivalent to the force on the gauge wheels. Thus, a single device can provide both depth adjustment and gauge wheel force measurement, without the need for the typical strain gauge. The system allows fluid pressure to be used both to change the depth that the seed is planted in the ground and how hard the planter gauge wheels are pushing on the ground in a single device.

In the illustrative system, the fluid port <NUM> in the fluid chamber <NUM> is connected to one or more valves to allow hydraulic fluid to be added to or removed from the chamber <NUM> to change the angle of the opener disc relative to the gauge wheel for any given soil condition.

The distance sensor <NUM> produces an output signal corresponding to the position of the piston within the hydraulic cylinder, which changes when the depth of the opening disc changes relative to the elevation of the gauge wheel. For example, if the soil engaged by the opening disc becomes harder, the depth of the opening disc becomes smaller unless the down pressure applied to the opening disc is increased. Conversely, if the soil engaged by the opening disc becomes softer, the depth of the opening disc becomes greater unless the down pressure applied to the opening disc is decreased. Thus, the position signal from the hydraulic cylinder actually represents the depth of the opening disc.

The small hydraulic ram <NUM> performs what would typically be a manual depth adjustment. The ram <NUM> pushes on a rocker arm <NUM>, which is connected to a link arm <NUM>, which is connected to a slider/depth adjuster <NUM>. The slider/depth adjuster <NUM> is free to move through the same adjustment range that the conventional depth adjustment handle could be moved manually to effect a depth adjustment.

The inductive distance sensor <NUM> that moves closer or farther away from a metal cam target <NUM> as the slider/depth adjuster <NUM> is moved throughout its adjustment range. The distance sensor <NUM> produces an output signal that is sent to an electronic controller that compares the signal from the distance sensor <NUM> with a desired depth value entered by the operator of the planter, as described in more detail below. A variety of linear or angular position sensors could be used in place of the illustrated distance sensor, which is preferred for its environmental protection and low cost.

As a controller compares the actual depth with the desired depth, it produces an output signal that controls a pair of valves that can be opened and closed to adjust the pressure in the hydraulic cylinder that receives the ram <NUM>. Changing this pressure extends or retracts the ram <NUM> to move the slider/depth adjuster <NUM> to the desired position. Thus, if the position of the ram <NUM> falls out of tolerance, the system will automatically open and close the valves to maintain the correct setting.

Also provided is a pressure sensor <NUM> that measures the pressure inside a hydraulic cylinder <NUM> that receives the ram <NUM>. It can be seen that the force exerted on the ground by the gauge wheels is transmitted from the tires to the gauge wheel arms <NUM>, both of which pivot and are supported by the pivoting equalizer <NUM>. This equalizer <NUM> is connected to the slider/depth adjuster <NUM>, which is connected to the link arm <NUM>, which is connected to the rocker arm <NUM>, which in turn contacts the ram <NUM>, which in turn compresses the fluid in the cylinder <NUM>, which is measured by a pressure sensor <NUM>. Thus, the pressure inside the cylinder <NUM> is equivalent to the force on the gauge wheels. In this way, a single device accomplishes both depth adjustment and gauge wheel force measurement, and eliminates the need for the typical strain gauge.

An objective of the present invention is to provide a planting system that enables the operator to select a desired planting depth setting, and then automatically maintains the actual planting depth within a selected range above and below the selected depth.

In one embodiment that provides both environmental protection and low cost, a pair of valves are controlled to open and close to extend or retract the ram of a hydraulic cylinder to move a slider/depth adjuster to the desired position. If the position of the slider/depth adjuster falls out of tolerance, the system automatically opens and closes the valve to maintain the correct setting. Each row unit may be provided with its own valves and associated control system.

The pressure inside the cylinder <NUM> is equivalent to the force on the gauge wheels. Thus, a single device can provide both depth adjustment and gauge wheel force measurement, without the need for the typical strain gauge. The system allows fluid pressure to be used both to change the depth that the seed is planted in the ground and how hard the planter gauge wheels are pushing on the ground in a single device.

In the illustrative system, a fluid port <NUM> in the fluid chamber <NUM> is connected to one or more valves to allow hydraulic fluid to be added to or removed from the chamber <NUM> to change the angle of the opener disc relative to the gauge wheel.

The distance sensor <NUM> produces an output signal representing the position of the cutting wheel support arm along the arcuate slot. That position changes as the angle between the two support arm changes with changes in the depth of the opener disc relative to the elevation of the gauge wheel (the soil surface). The output signal from the distance sensor <NUM> will be referred to as the "seed depth" signal because the depth of the opener disc determines the depth of the furrow in which the seed is planted.

The position sensor produces an output signal corresponding to the position of the piston within the hydraulic cylinder, which changes when the depth of the opener disc changes relative to the elevation of the gauge wheel. For example, if the soil engaged by the opening disc becomes harder, the depth of the opening disc becomes smaller unless the down pressure applied to the opening disc is increased. Conversely, if the soil engaged by the opening disc becomes softer, the depth of the opening disc becomes greater unless the down pressure applied to the opening disc is decreased. Thus, the position signal from the hydraulic cylinder actually represents the depth of the opening disc.

The output signal from the position sensor is supplied to the controller, which determines whether any change in that signal falls within predetermined dead bands on opposite sides of the target value. If a change exceeds a dead band, the controller produces a control signal that increases or decreases the down pressure on the opening disc to maintain the depth of the opening disc within a desired range on both sides of the target value.

The target value can be changed automatically as the planter traverses a field having variable soil conditions. For example, a soil moisture sensor can be used to determine optimum target values in different areas of a field being planted. Another example is to use stored data corresponding to the soil properties at different GPS locations in the field to adjust the target value as the planter traverses those locations.

The gauge wheel support arms <NUM> push against an equalizer support which is connected to the slider/depth adjuster <NUM> that slides along an arcuate guide. Movement of the slider/depth adjuster <NUM> along the arcuate guide moves one end of the link arm <NUM> that is attached at its other end to the rocker arm <NUM> mounted for pivoting movement abound a stationary pivot pin <NUM>. The lower end of the rocker arm <NUM> engages the ram <NUM> in the hydraulic cylinder <NUM> that is filled with a pressurized hydraulic fluid.

The force on the gauge wheels due to the weight of the row unit and applied down force causes the rocker arm <NUM> to pivot around the pivot bolt <NUM> and push against the hydraulic ram <NUM>. This force on the ram <NUM> controls the pressure on the fluid in the cylinder <NUM>, so the fluid pressure in the cylinder <NUM> is proportional to the amount of gauge wheel load. This fluid pressure controls the depth of the opener blade by controlling the angle between the support arms for the gauge wheel and the opener blade.

To adjust the depth of the opener blade, the pressure of the hydraulic fluid in the cylinder <NUM> can be adjusted by increasing or decreasing the amount of hydraulic fluid in the cylinder. This is accomplished by a pair of valves that can be opened and closed by electrical signals from an electrical controller.

The fluid cylinder <NUM> includes a fluid port <NUM> that is connected to one or more valves to allow hydraulic fluid to be added to or removed from the cylinder <NUM> to change the angle of the opener disc relative to the gauge wheel. The distance sensor <NUM> produces an output signal representing the position of the opener disc support arm <NUM> along an arcuate guide, which changes as the angle between the two support arms changes with changes in the depth of the opener disc relative to the elevation of the gauge wheel (the soil surface). The output signal from the distance sensor <NUM> can be referred to as the "seed depth" signal because the depth of the opener disc determines the depth of the furrow in which the seed is planted.

<FIG> is a flow chart of an algorithm for generating signals that control the one or more valves that control the flow of hydraulic fluid in and out of the fluid chamber <NUM>. At step <NUM>, this algorithm calibrates the distance or angle sensor to read the correct seed depth in inches, and step <NUM> calibrates the pressure sensor <NUM> to read the gauge wheel force in pounds or kilograms. Step <NUM> computes the target seed depth and down pressure based on the output of step <NUM> and external soil property data, furrow hardness sensor data and/or moisture sensor data. Then seed depth dead band values are entered at step <NUM>, and down pressure dead band values are entered at step <NUM>.

Step <NUM> in this algorithm determines whether the planter row unit is in an operating configuration on the ground, as will be described in detail below. When step <NUM> produces an affirmative answer, step <NUM> measures the actual seed depth, and step <NUM> measures the actual gauge wheel load. Steps <NUM> and <NUM> then determine whether the actual seed depth and the actual gauge wheel load are within their respective dead bands and, if the answer is negative in either case, whether the actual value is above or below that dead band.

In the case of the seed depth, if the actual seed depth is within the dead band, the system returns to step <NUM> to repeat steps <NUM>-<NUM>. If the actual seed depth is outside the dead band and is too deep, step <NUM> opens a valve to supply additional hydraulic fluid to the cylinder <NUM> for a brief time interval. If the actual seed depth is outside the dead band and too shallow, step <NUM> opens a valve to allow hydraulic fluid to flow out of the cylinder <NUM> for a brief time interval.

In the case of the gauge wheel load, if the actual gauge wheel load is above the dead band, step <NUM> opens a valve to supply additional hydraulic fluid to the cylinder <NUM>. If the actual gauge wheel load is above the dead band, step <NUM> decreases the down pressure actuator pressure. If the actual gauge wheel load is below the dead band, step <NUM> increases the down pressure actuator pressure. If the actual gauge wheel load is within the dead band, the system returns to step <NUM> to repeat steps <NUM>-<NUM>. When step <NUM> produces a negative answer, step <NUM> performs an active air purge process, and step <NUM> maintains the row unit down pressure at zero for safety.

Referring to <FIG>, a modified system (e.g., an agricultural planting system) <NUM> enables an operator to select a desired planting depth setting, and then maintains the actual planting depth within a selected range above and below the selected depth. The agricultural planting system <NUM> is the same as, or similar to, the modified system of <FIG>, where like reference numbers are used for like elements, except that the agricultural planting system <NUM> may further include a GPS device <NUM>. According to one embodiment, the agricultural planting system <NUM> includes an agricultural planter <NUM>, an opener device, a gauge wheel <NUM>, a GPS device <NUM>, and a controller <NUM>. The opener device is mounted on the agricultural planter <NUM> for engaging the ground of a field. The gauge wheel <NUM> is mounted on the agricultural planter <NUM> for rotating on the ground of the field. The GPS device <NUM> is communicatively coupled and physically affixed to the agricultural planter <NUM>.

The agricultural planting system <NUM> optionally includes a fluid chamber <NUM> having a fluid port <NUM> that is connected to one or more valves to allow hydraulic fluid to be added to or removed from the chamber <NUM> to change the angle of the opener disc relative to the gauge wheel. As shown, the distance sensor <NUM> produces an output signal representing the position of the opener disc support arm along the arcuate guide. The position of the opener disc support arm changes with changes in the depth of the opener disc relative to the elevation of the gauge wheel (the soil surface). The output signal from the distance sensor <NUM> is referred to as the "seed depth" signal because the depth of the opener disc determines the depth of the furrow in which the seed is planted.

The GPS device <NUM> is configured to determine a location of the agricultural planter <NUM> in the field. The controller <NUM> is in electrical communication with both the agricultural planter <NUM> and the GPS device <NUM>. The controller <NUM> has predetermined settings associated with a map of the field. For example, the map of the field may consist of stored data corresponding to soil properties at different GPS locations in the field for adjusting the target value as the planter traverses those locations. The controller <NUM> is configured to select a relative elevation of the opener device and the gauge wheel <NUM> based at least in part on the location determined by the GPS device <NUM>. The controller <NUM> is further configured to produce, based on the location, a signal for adjusting the depth of engagement into the ground of the opener device. In some implementations, the relative elevation of the opener device and the gauge wheel <NUM> is selected automatically in response to the map of the field.

Further referring to the illustration of <FIG>, step <NUM> computes the target seed depth and down pressure based on the output of step <NUM> and external soil property data, furrow hardness sensor data and/or moisture sensor data. The external soil property data, furrow hardness sensor data and/or moisture sensor data can be represented by the map of the field for determining the target seed depth. One benefit of the map is to control the planting depth in real time as the agricultural planter <NUM> and/or opener traverses the field, because it is critical that the seeds all be planted into moisture so that each seed emerges from the soil at the same time. As such, the map of the field includes a topographical map, a soil temperature map, a soil moisture map, or the like, or in any combination thereof.

According to some embodiments of the present disclosure, the agricultural planting system further includes a plurality of sensors <NUM> (illustrated in <FIG>) communicatively coupled to the controller <NUM>. Each of the plurality of sensors <NUM> is positioned in a respective one of a plurality of zones of the field. The plurality of sensors <NUM> is configured to measure soil properties. For example, the soil properties measured by the plurality of sensors <NUM> include a moisture level, and a soil moisture sensor can be used to determine optimum target values in different areas of a field being planted. As another example, the plurality of sensors <NUM> is a plurality of remote sensors configured to capture a plurality of aerial images. Each of the plurality of aerial images captures the respective one of the plurality of zones of the field.

The map of the field is associated with the soil properties measured by the plurality of sensors <NUM>. As described above, the map of the field may consist of stored data, such as external soil property data, soil temperature data, air pressure data, humidity data, furrow hardness data, soil moisture data, or the like. Additionally or alternatively, the map of the field can be updated periodically (e.g., every hour, every day, every week, every month, etc.) according to the soil properties measured by the plurality of sensors.

According to some embodiments of the present disclosure, the plurality of sensors <NUM> includes at least one soil moisture sensor. Instead of or in addition to being remote from the agricultural planter <NUM>, the at least one soil moisture sensor <NUM> can include a local moisture sensor <NUM> (illustrated in <FIG>) mounted on the agricultural planter <NUM> and in contact with the ground being engaged by the opener device. In response to the soil moisture level measured by the local moisture sensor <NUM>, the controller <NUM> is configured to produce a signal for adjusting the depth of engagement into the ground of the opener device. The map of the field may be updated according to the soil moisture level measured by the local moisture sensor <NUM> at each GPS location measured by the GPS device <NUM>.

The map of the field may also be updated to include a seed depth associated with each GPS location. Each seed depth at its respective GPS location may be cross-referenced with other seed depths at their respective GPS locations, for determining the relative elevation of the opener device and the gauge wheel <NUM>, based at least in part on (<NUM>) the local soil moisture level measured by the local moisture sensor <NUM>, (<NUM>) the stored soil moisture data from the map of the field, and/or (<NUM>) the soil moisture level measured by the plurality of remote sensors <NUM>.

Claim 1:
An agricultural planting system for controlling the depth of an opener device in an agricultural planter, the agricultural planting system comprising:
an agricultural planter;
an opener device mounted on the agricultural planter for engaging the ground of a field;
a gauge wheel mounted on the agricultural planter for rotating on the ground of the field;
at least one soil-moisture sensor configured to measure a moisture content of the soil in the ground; and
a controller in electrical communication with the agricultural planter and the at least one soil-moisture sensor,
characterized in that
the controller (<NUM>) is configured to
select a relative elevation of the opener device and the gauge wheel based at least in part on a map of the field representing the moisture content measured by the at least one soil-moisture sensor as a soil moisture map and on a topographical map, and
produce, based on the map of the field including the soil moisture map and the topographical
map, a signal for adjusting the depth of engagement into the ground of the opener device.