Depth control for ground engaging tools of an implement

The present inventors have recognized that hydraulic cylinders for raising and lowering ground engaging tools of an implement can be synchronously controlled with respect to a prioritized primary set of tools, such as a section of tillage shanks for ripping compacted soil, which cylinder adjustment affects all other sections due to the arrangement of the primary set on the frame. A user can electronically command new ground engaging depths for the primary set and/or any secondary set of ground engaging tools. If the primary set is updated, the system can synchronously control the primary set and the other sections to adjust respective cylinders to achieve desired depths. However, if only a second set is updated, and not the primary set, the system can control only the second set to adjust its cylinder to the desired depth without affecting the primary set or any other second set.

FIELD OF THE INVENTION

The present invention relates generally to agricultural systems having ground engaging tools, and more particularly, to systems in which a change for a ground engaging depth for a primary set causes changes in hydraulic cylinder lengths for the primary set and a secondary set whereas a change for a ground engaging depth for the secondary set causes a change in hydraulic cylinder length for only the secondary set.

BACKGROUND OF THE INVENTION

Farmers utilize a wide variety of tillage implements to prepare soil for planting. Some such implements include two or more sections (or sets of tools) coupled together to perform multiple functions as they are pulled through the fields by a tractor, for example, a cultivator/harrow which is capable of simultaneously tilling and leveling the soil in preparation for planting. This implement includes a cultivator that is towed by a tractor in a harrow that is towed by the cultivator.

It is often desirable to configure the sections (or sets) of the implement to engage the ground at different depths and at different times. For example, with an implement having a first section of disc blades for cutting agricultural residue, a second section of tillage shanks for ripping compacted soil, a third section of leveling discs for distributing soil, and/or a fourth section of baskets for breaking soil clods, such as the Ecolo-Tiger 875 disk ripper available from CNH Industrial, it is oftentimes desirable to set ground engaging depths for the respective sections to different depths. Moreover, it is oftentimes desirable to change ground engaging depths for particular sections and particular times. However, changing a ground engaging depth of one section may inadvertently result in a changed ground engaging depth of a different section. It is therefore desirable to provide a system for controlling depth of ground engaging tools of an implement that is easier to configure and use in the field.

SUMMARY OF THE INVENTION

The present inventors have recognized that hydraulic cylinders for raising and lowering ground engaging tools of an implement can be synchronously controlled with respect to a prioritized primary set of tools, such as a section of tillage shanks for ripping compacted soil, which cylinder adjustment affects all other sections due to the arrangement of the primary set on the frame. A user can electronically command new ground engaging depths for the primary set and/or any secondary set of ground engaging tools. If the primary set is updated, the system can synchronously control the primary set and the other sections to adjust respective cylinders to achieve desired depths. However, if only a second set is updated, and not the primary set, the system can control only the second set to adjust its cylinder to the desired depth without affecting the primary set or any other second set.

In one aspect, operation of an implement, such as an Ecolo-Tiger 875 disk ripper, can require independent adjustment of a main depth (“D1,” also noted as “MD,” via an MD cylinder, also noted as “C1”), a front disk frame depth (“D2,” also noted as “DF,” via a DF cylinder, also noted as “C2”), a main frame tilted angle or Fore-Aft (“D4,” also noted as “FA,” via an FA cylinder, also noted as “C4”), and a rear leveler near ground (“D3,” also noted as “Lr,” via an Lr cylinder, also noted as “C3”) with respect to ground. However, the implement's design is such that DF, Lr and FA move along a shank depth adjustment if DF, Lr, and/or FA cylinders are locked. This is because their cylinders are attached on main frame. Thus, with DF, Lr, and/or FA being set and maintained, whenever MD is adjusted, DF, Lr, and/or FA are to be adjusted in an opposite direction. This corresponding adjustment is “coordinated control.” Ideally, such coordinated control is “synchronous.” A parallel control strategy is based on depth adjustment target; a new DF, Lr, and/or FA target are calculated with the condition of keeping their settings the same. Then, 4 functions' cylinder is independently driven to their targets. With parallel control, there is no interaction among and no significant initial delay; however, during movement, there can be some control error due to load differences, hydraulic gain differences and/or potentially, flow sequent supply. With series control, there is a master/slave control mode, i.e. DF, Lr, and/or FA take the corresponding transformation of MD's instantaneous position as their new instantaneous Target. However, DF, Lr, and/or FA could have some lag error or accumulated error due to delay of the hydraulic and control system, and/or a slower response when compared to an electric control system. The present invention provides a parallel plus series synchronous control method.

Specifically then, one aspect of the present invention can provide an agricultural implement, including: a frame supported by multiple wheels; multiple ground engaging tools supported by the frame, the ground engaging tools including a primary set and at least one secondary set, in which each set includes a hydraulic cylinder arranged with respect to the frame for raising and lowering the set, and in which each set is configured to engage the ground at a ground engaging depth when lowered to be in contact with the ground; a hydraulic system comprising a pump configured to supply hydraulic fluid and multiple electronically controlled valves, in which each electronically controlled valve is configured to meter hydraulic fluid with respect to a hydraulic cylinder; operator controls for configuring a ground engaging depth for each set; and a controller in communication with the hydraulic system and the operator controls, the controller executing a program stored in a non-transient medium to: upon receiving from the operator controls a change for a ground engaging depth for the primary set, calculate a cylinder length target for a hydraulic cylinder of the primary set and for each secondary set for achieving the ground engaging depth for each set, and control the hydraulic system to adjust the hydraulic cylinder of each set to the cylinder length target calculated for the set; and upon receiving from the operator controls a change for a ground engaging depth for a secondary set, calculate a cylinder length target for a hydraulic cylinder of only the secondary set for achieving the ground engaging depth for the set, and control the hydraulic system to adjust the hydraulic cylinder of only the secondary set to the cylinder length target calculated for the set.

Another aspect of the present invention can provide a method for changing ground engaging depths for tools of an agricultural implement, the agricultural implement including a frame supported by multiple wheels, multiple ground engaging tools supported by the frame, the ground engaging tools including a primary set and at least one secondary set, in which each set includes a hydraulic cylinder arranged with respect to the frame for raising and lowering the set, and in which each set is configured to engage the ground at a ground engaging depth when lowered to be in contact with the ground, and a hydraulic system including a pump configured to supply hydraulic fluid and multiple electronically controlled valves, in which each electronically controlled valve is configured to meter hydraulic fluid with respect to a hydraulic cylinder, the method including: configuring a ground engaging depth for each set; upon receiving a change for a ground engaging depth for the primary set, calculating a cylinder length target for a hydraulic cylinder of the primary set and for each secondary set for achieving the ground engaging depth for each set, and controlling the hydraulic system to adjust the hydraulic cylinder of each set to the cylinder length target calculated for the set; and upon receiving a change for a ground engaging depth for a secondary set, calculating a cylinder length target for a hydraulic cylinder of only the secondary set for achieving the ground engaging depth for the set, and controlling the hydraulic system to adjust the hydraulic cylinder of only the secondary set to the cylinder length target calculated for the set.

DETAILED DESCRIPTION

Referring now to the drawings, and more particularly toFIG. 1, there is shown by way of example an agricultural system10which generally includes a tractor12and an agricultural implement14for tilling and finishing soil prior to seeding. With additional reference toFIGS. 2 and 3showing top and sides views, respectively, the implement14can be configured as a multi-section (combination tool) field disk ripper, such as the Ecolo-Tiger 875 disk ripper, as available from CNH Industrial. The implement14can include a carriage frame16which can directly towed by a traction unit, such the tractor12. The frame16can include a pull hitch18generally extending in a travel direction20, and forward and aft directed carrier frame members22which are coupled with and extend from pull hitch18. Reinforcing gusset plates may be used to strengthen the connection between pull hitch18and carrier frame members22.

The frame16can be supported by multiple wheels24. The wheels24can be pivoted between a field operation position and a transport position by actuator assemblies associated with the wheels. The frame16, in turn, can support multiple ground engaging tools30that are useful for field operations, including a primary set of ground engaging tools30aand one or more secondary sets of ground engaging tools, such as secondary sets30band30c. In one aspect, the primary set of ground engaging tools30acould comprise tillage shanks for ripping compacted soil. A secondary set of ground engaging tools30bcould comprise disc blades for cutting agricultural residue, such as corn stalks, that are arranged forward of the tillage shanks. Another secondary set of ground engaging tools30ccould comprise leveling discs for distributing soil, and/or baskets (or “crumblers”) for breaking large soil clods, which are arranged rearward of the leveling discs.

Each set of ground engaging tools includes one or more hydraulic cylinders40arranged with respect to the frame16. The hydraulic cylinders40are configured to raise and lower each respective set of ground engaging tools30with respect to the frame16. Accordingly, each set of ground engaging tools30can be configured to engage the ground at a ground engaging depth (“D”), when lowered by respective hydraulic cylinders40, to be in contact with the ground. For example, the primary set of ground engaging tools30acan include one or more cylinders40a(such as cylinder40aidentified as “C1LH” and cylinder40a′ identified as “C1RH” on left and right sides, respectively, mechanically linked through a rockshaft, but hydraulically plumbed in parallel) identified as “C1” for raising and lowering the tillage shanks for engaging the ground at a tillage ground engaging depth “D1;” the secondary set of ground engaging tools30bcan include one or more cylinders40b(identified as “C2”) for raising and lowering the disc blades for engaging the ground at a disc blade ground engaging depth “D2;” and the secondary set of ground engaging tools30ccan include one or more cylinders40c(such as cylinder40cidentified as “C3LH” and cylinder40c′ identified as “C3RH” on left and right sides, respectively, which are not mechanically linked through a rockshaft, but are hydraulically plumbed in parallel) identified as “C3” for raising and lowering the leveling discs and/or baskets for engaging the ground at a leveling ground engaging depth “D3.” In addition, a hydraulic cylinder40d(identified as “C4”) can be arranged with respect to the frame16for changing an angle of the frame16(identified as “D4”) with respect to the ground, preferably for leveling the frame16with respect to the hitch18and the tractor12.

In operation, retracting C1lowers the frame16(and the primary set30a), whereas extending C1raises the frame16; extending C2raises the disc blades (the secondary set30b), whereas retracting C2lowers the disc blades; extending C3raises the leveling discs and/or baskets (the secondary set30c), whereas retracting C3lowers the leveling discs and/or baskets; and extending C4pitches the implement14forward (angle of the frame16), whereas retracting C4pitches the implement14rearward.

A maximum ground engaging depth D1for the primary set30acan typically be greater than a maximum ground engaging depth for any secondary set, such as30band/or30c. For example, the maximum ground engaging depth for the primary set30acomprising tillage shanks could be at least 14 inches. However, during a work or field mode, the maximum ground engaging depth for the secondary sets30bor30c, comprising disc blades and/or leveling discs, could be 3 to 4 inches.

With additional reference toFIG. 4, a schematic diagram for a ground engaging depth control system50, located on the implement14or tractor12, for synchronously controlling ground engaging depths D1, D2, D3and D4(angle), by way of cylinders C1, C2, C3and C4, is provided in accordance with aspect of the invention. Each cylinder40includes a movable “piston” or rod52that is extendable and retractable from a “cap” or base54of the cylinder40, as fluidly controlled by a hydraulic system including an electronically controlled valve system56, a fluid reservoir62and a pump64. Each cylinder40can be a double acting, single ended hydraulic cylinder with an integrated linear position sensor, such as those described in U.S. Pat. Nos. 7,307,418, 7,259,553, and 7,034,527, the disclosures of which are incorporated herein by reference. In particular, a sensor58, such as a linear potentiometer, integrated with respect to the cylinders40, can provide a signal to a controller60indicating a linear displacement of the respective cylinder40, reflected by an amount of extension or retraction of the rod52. The controller60can selectively energize one or more electronically controlled valves, via solenoids, of the valve system56operably connected to the cylinder40. Valves of the valve system56can meter-in and meter-out hydraulic fluid with respect to cylinders40for precise control of cylinder lengths. The solenoids are fluidly connected to the fluid reservoir62that includes the pump64configured to supply hydraulic fluid from the fluid reservoir62. The pump64could supply hydraulic fluid at a pressure, for example, of at least 3000 psi (pounds per square inch). To extend the rod52of any particular cylinder40, hydraulic fluid can be supplied to the cylinder40through a base port70, while hydraulic fluid is also withdrawn from the cylinder40through a rod port72, as controlled by the valve system56and the controller60. Also, to retract the rod52of any particular cylinder40, hydraulic fluid can be supplied to the cylinder40through the rod port72, while hydraulic fluid is also withdrawn from the cylinder40through the base port70, as controlled by the valve system56and the controller60.

The controller60can selectively energize solenoids of the valve system56to vary any of the cylinder lengths C1, C2, C3and/or C4to achieve ground engaging depths D1, D2, D3and/or D4(angle) as desired. Operator controls66, which could be within an operator cab of the tractor12, can receive inputs from an operator for configuring ground engaging depths D1, D2, D3and/or D4(angle) as desired. Various displays68, which could also be within the operator cab, can provide feedback to the operator, including progress toward achievement of the desired ground engaging depths D1, D2, D3and/or D4(angle).

In accordance with an aspect of the invention, cylinders40can be synchronously controlled with respect to the primary set of ground engaging tools30a, also being a prioritized set of tools. This is due to cylinder adjustment of the primary set of ground engaging tools30aaffecting relative depths of all other sets of ground engaging tools30, i.e., secondary sets of ground engaging tools30band30c, and angle of the frame16, due to their arrangement on the frame16. A user can electronically command new ground engaging depths for the primary set of ground engaging tools30aand/or any secondary sets of ground engaging tools30band/or30cand/or angle of the frame16. If ground engaging depth D1of the primary set30ais updated, the system can synchronously control respective cylinders C1, C2, C3and/or C4, to achieve desired depths and angle, including D1, D2, D3and/or D4(angle), calculated based on the physical geometry of the implement14. However, if only a secondary set30band/or30cis updated, or the angle of the frame16is updated, and not the primary set30a, the system can control only the secondary set30band/or30cand or angle of the frame16to adjust its cylinder C2, C3or C4to the desired depth or angle without affecting the primary set or any other second set. In particular, the controller60executing a program stored in a non-transient medium69to, upon receiving from the operator controls66a change for a ground engaging depth D for the primary set30a, calculate a cylinder length target for a hydraulic cylinder40of the primary set30aand for each secondary set30band30cand angle of the frame16for achieving the ground engaging depth for each set and the angle, and control the hydraulic system to adjust the hydraulic cylinder40of each to the cylinder length target calculated. The controller60can further execute to, upon receiving from the operator controls66a change for a ground engaging depth D2or D3for secondary set30band/or30c, or angle D4for the angle of the frame16, calculate a cylinder length target for a hydraulic cylinder40of only the secondary set30band/or30cor angle of the frame16for achieving the ground engaging depth or angle, and control the hydraulic system to adjust the hydraulic cylinder40of only the secondary set30band/or30cor angle of the frame16to the cylinder length target calculated.

With additional reference toFIG. 5is a flow diagram80for controlling ground engaging depths is provided in accordance with aspect of the invention. Beginning at step82, the system can receive inputs from an operator via the operator controls66. Next, at decision step84, the system can determine whether D1, a prioritized ground engaging depth, has been updated. If D1has been updated (“Yes”), the system can proceed to step86to calculate cylinder length targets for C1, C2, C3and/or C4for achieving the ground engaging depth and angle presently configured. Then, at step88, the system can control the hydraulic system to adjust the aforementioned cylinders40to the cylinder length targets calculated for each. Preferably, the system can execute a closed loop control system, with the feedback from sensors58, to adjust each cylinder to a cylinder length within a tolerance band of the cylinder length targets. The process can then return to step82for further inputs.

With additional reference toFIG. 6, a timing diagram illustrates one aspect in which the aforementioned steps86and88can be accomplished with a minimization of dynamic error. At the outset, it should be noted that ground engaging depths and/or angles “D” (such as D1, D2, D3, D4) correspond to earth or ground coordinates, whereas cylinder lengths “C” (such as C1, C2, C3, C4) correspond to control of cylinders with respect to frame coordinates (such as the frame16) as secondary sets. At the moment t1, an operator can set a command with respect to mainframe depth, such as lowering the primary set of ground engaging tools30a. The controller60can execute to determine the D1target according to ground coordinates and the C2target according to frame coordinates. Then, the cylinders40can be controlled to gradually ramp from their current positions to the new targets at t2. The C1cylinder can begin response to the C1target profile. However, some control error can occur due to a delay122which could be due to, for example, ground conditions, hydraulic system interactions, and the like.

During the dynamic control process of C1, the controller60can also execute to instantaneously determine the C2dynamic target with respect to the frame. The C2cylinder is controlled not only according to the C2target, which was determined at t1, but also at the same time according to the C2dynamic target. This combined control method can achieve a satisfied control error, limiting a control error of D2to within a defined D2error band. The large control error124can be avoided due to the significant delay122of the mainframe control system with C1, so long as control of C2is based on the C2target determined at t1. Also, the large fluctuation126can be limited due to delay in the control of C2, so long as the control of C2is based on the C2dynamic target. C3(and D3) and C4(and D4) can be similarly controlled like C2(and D2).

Referring again toFIG. 5, if at decision step84the system determines that D1, the prioritized ground engaging depth, has not been updated (“No”), the system can instead proceed to decision step90. At decision step90, the system can determine whether D2, a secondary set, has been updated. If D2has been updated (“Yes”), the system can proceed to step92to calculate a cylinder length target for only C2for achieving the ground engaging depth D2. Then, at step94, the system can control the hydraulic system to adjust the only aforementioned cylinder C2to the cylinder length target that was calculated. Preferably, the system can execute a closed loop control system, with the feedback from sensor58for C2, to adjust C2to a cylinder length within a tolerance band of the cylinder length target. The process can then continue to decision step96. However, if at decision step90the system determines that D2, a non-prioritized ground engaging depth, has not been updated (“No”), the system can instead continue directly to decision step96.

Similarly, at decision step96, the system can determine whether D3, another secondary set, has been updated. If D3has been updated (“Yes”), the system can proceed to step98to calculate a cylinder length target for only C3for achieving the ground engaging depth D3. Then, at step100, the system can control the hydraulic system to adjust only the aforementioned cylinder C3to the cylinder length target that was calculated. Preferably, the system can execute a closed loop control system, with the feedback from sensor58for C3, to adjust C3to a cylinder length within a tolerance band of the cylinder length target. The process can then continue to decision step96. The process can then continue to decision step102. However, if at decision step96the system determines that D3, a non-prioritized ground engaging depth, has not been updated (“No”), the system can instead continue directly to decision step102.

Similarly, at decision step102, the system can determine whether D4, the angle of the frame16, has been updated. If D4has been updated (“Yes”), the system can proceed to step104to calculate a cylinder length target for only C4for achieving the ground angle D4. Then, at step106, the system can control the hydraulic system to adjust only the aforementioned cylinder C4to the cylinder length target that was calculated. Preferably, the system can execute a closed loop control system, with the feedback from sensor58for C4, to adjust C4to a cylinder length within a tolerance band of the cylinder length target. The process can then continue to decision step96. The process can then return to step82for further inputs. However, if at decision step102the system determines that D4, a non-prioritized angle, has not been updated (“No”), the system can instead continue directly to step82.