Agricultural mowing system with overlap control

An agricultural mowing system includes: a driving vehicle having a steerable axle and a pivotable tongue and defining a travel axis; a first mower coupled to the driving vehicle; a second mower coupled to the tongue; a tongue actuator configured to pivot the tongue; a tongue angle sensor configured to output signals corresponding to a tongue angle of the tongue; and a controller operatively coupled to the tongue actuator and the tongue angle sensor. The controller is configured to: determine a lateral overlap or underlap of the mowers exceeds a threshold value based at least partially on the tongue angle and a steering angle of the steerable axle; determine a correction angle needed for the tongue to pivot such that the lateral overlap or underlap no longer exceeds the threshold value; and output a correction signal to the tongue actuator to pivot the tongue by the correction angle.

FIELD OF THE INVENTION

The present invention pertains to agricultural vehicles and, more specifically, to agricultural mowers and mower conditioners.

BACKGROUND OF THE INVENTION

Mowers and mower-conditioners are often employed to cut hay and/or other standing plants, such as grass, in a field. For cutting large fields, many mowing systems include a driving vehicle that pushes a mower (or mower-conditioner) in front of the vehicle while simultaneously pulling another mower (or mower-condition) behind the vehicle.

It is known that a slight lateral overlap is desired between the front mower and the rear mower to ensure that all of the standing plants are cut and no patches of uncut plants are left behind in a pass, which results due to lateral “underlap”. Various mechanisms are known for adjusting the lateral overlap between the front and rear mowers, but such solutions can be overly complex and unreliable.

What is needed in the art is an agricultural mowing system that can address some of the previously described issues with known systems.

SUMMARY OF THE INVENTION

Exemplary embodiments disclosed herein provide an agricultural mowing system with a controller that can cause a tongue actuator to pivot a mower responsively to the controller determining that a lateral overlap or underlap exceeds a threshold value.

In some exemplary embodiments provided according to the present disclosure, an agricultural mowing system includes: a driving vehicle having a chassis, a steerable axle carried by the chassis, and a tongue coupler carried by the chassis, the driving vehicle defining a travel axis; a first mower having a plurality of first cutting elements and coupled to the driving vehicle; a second mower having a plurality of second cutting elements and a pivotable tongue coupled to the tongue coupler; a tongue actuator associated with the tongue and configured to pivot the tongue; a tongue angle sensor associated with the tongue and configured to output tongue angle signals corresponding to a tongue angle of the tongue relative to the travel axis; and a controller operatively coupled to the tongue actuator and the tongue angle sensor. The controller is configured to: determine a lateral overlap or underlap of the first mower and the second mower, relative to the travel axis, exceeds a threshold value based at least partially on the tongue angle and a steering angle of the steerable axle; determine a correction angle needed for the tongue to pivot such that the lateral overlap or underlap no longer exceeds the threshold value; and output a correction signal to the tongue actuator to cause the tongue actuator to pivot the tongue by the correction angle.

In some exemplary embodiments, a method of controlling an agricultural mowing system is provided. The agricultural mowing system includes a driving vehicle having a steerable axle and a tongue coupler, a first mower coupled to the driving vehicle, and a second mower including a pivotable tongue coupled to the tongue coupler. The method is performed by a controller and includes: determining a lateral overlap or underlap of the first mower and the second mower, relative to a travel axis of the driving vehicle, exceeds a threshold value based at least partially on a tongue angle of the tongue and a steering angle of the steerable axle; determining a correction angle needed for the tongue to pivot such that the lateral overlap or underlap no longer exceeds the threshold value; and outputting a correction signal to a tongue actuator to pivot the tongue by the correction angle.

One possible advantage that may be realized by exemplary embodiments disclosed herein is that the controller can determine that the lateral overlap or underlap exceeds the threshold value by utilizing known geometry of the vehicle and the mowers and cause the tongue actuator to adjust the tongue so the overlap or underlap no longer exceeds the threshold value.

Another possible advantage that may be realized by exemplary embodiments disclosed herein is that tongue can be adjusted using fewer inputs to the controller than known systems, which can significantly reduce the system complexity and computing power necessary to control the tongue.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, and more particularly toFIG.1, an exemplary embodiment of an agricultural mowing system100provided according to the present disclosure is illustrated. The mowing system100includes a driving vehicle110, a first mower120coupled to the driving vehicle110, and a second mower130coupled to the driving vehicle110. In other words, the mowing system100is a tandem mowing system that includes at least two mowers120,130operating in tandem to cut plants from a field. It should be appreciated that while only two mowers120,130are illustrated and described herein, the present disclosure is equally applicable to mowing systems that incorporate more than two mowers, such as mowing systems that include three or more mowers.

The driving vehicle110includes a chassis111and a power source, such as an internal combustion engine (ICE)112, to provide motive force to a plurality of wheels113,114. Some of the wheels, such as front wheels113, may be coupled to the chassis111by a steerable front axle115while the rear wheels114are coupled to the chassis111by a fixed rear axle116. It should be appreciated that, alternatively, the front axle115may be a fixed axle and/or the rear axle116may be a steerable axle. In some embodiments, a steering angle sensor117is associated with the steerable axle115and configured to output a steering angle signal that corresponds to a steering angle of the steerable axle115, as will be described further herein. The chassis111also carries a tongue coupler118that allows coupling of the second mower130to the driving vehicle110, as will be described further herein. As illustrated, the driving vehicle110is in the form of a tractor, but it should be appreciated that the driving vehicle110may be other types of vehicles.

The first mower120and the second mower130each carry a respective set of cutting elements121,131that can cut standing plants as the mowers120,130travel across the field. The mowers120,130are each coupled to the driving vehicle110. The first mower120, for example, may be center mounted to the driving vehicle110in a “fixed” manner so the first mower120is generally static relative to the driving vehicle110. The second mower130, on the other hand, is coupled to the tongue coupler118by a pivotable tongue133that can change the angular position of the second mower130relative to a travel axis TA defined by the driving vehicle110, which generally corresponds to a travel direction of the driving vehicle110. In this sense, the first mower120can be in-line with the travel axis TA so the first mower120is generally co-axial with the travel axis TA. The second mower130, on the other hand, can be angled and laterally offset from the travel axis TA and the first mower120by pivoting the tongue133. A lateral offset X of the second mower130, relative to the travel axis TA and the first mower120, can be defined between a mower axis MA of the second mower130and the travel axis TA.

A tongue actuator140is associated with the tongue133and configured to pivot the tongue133. As used herein, the tongue actuator140is “associated” with the tongue133in the sense that the tongue actuator140is somehow connected, either directly or indirectly, to the tongue133in a manner that allows actuating movement of the tongue actuator140to pivot the tongue133. The tongue actuator140may be, for example, a hydraulic actuator in the form of a cylinder that is powered by a hydraulic system of the driving vehicle110. In some embodiments, the tongue actuator140is also carried by the second mower130. It should be appreciated that the tongue actuator140can also be carried by the tractor110to pivot the tongue133.

A tongue angle sensor150is associated with the tongue133and configured to output tongue angle sensors corresponding to a tongue angle α relative to the travel axis TA. The tongue angle sensor150may be, for example, a rotary sensor that is carried by the second mower130adjacent to the tongue133to sense the tongue angle α and/or may be mounted at the tongue coupler118of the driving vehicle110. Alternatively, the tongue angle sensor150may be part of the tongue actuator140; in such a case, the tongue actuator140may be a “smart” actuator that may include absolute positioning features that translate extension/retraction directly to the tongue angle α relative to the travel axis TA. In other words, in some embodiments the tongue actuator140may also function as the tongue angle sensor150. Many different types of angle sensors are known, so further description is omitted for brevity.

A controller160, such as a tractor controller, is operatively coupled to the tongue actuator140and the tongue angle sensor150to communicate via electronic signals. The controller160may be, for example, a central tractor controller that is configured to control a variety of tractor functions. Alternatively, the controller160may be an application specific controller that is specifically configured to control the orientation of the second mower130relative to the driving vehicle110by causing the tongue actuator140to pivot the tongue133.

As illustrated inFIG.1, the first mower120travels in front of the driving vehicle110and the second mower130travels behind the driving vehicle110. Due to the orientation of the mowers120,130, the mowers120,130are overlapped with one another laterally, relative to the travel axis TA, as designated by the illustration of a lateral overlap O. Lateral overlapping of the mowers120,130significantly reduces the possibility of standing plants being left on the field in areas that the mowers120,130have traveled across. Overlapping the mowers120,130also eliminates so-called lateral underlap between the mowers120,130, which would leave behind areas of standing plants due to the mowers120,130not traversing the underlapped area. It should be appreciated that “overlap” and “underlap” described herein refers to lateral overlap or underlap relative to the travel axis TA and, as used herein, “lateral” refers to the direction of an axis that extends orthogonally relative to the travel axis TA.

In known mowing systems, the overlap and underlap of the tandem mowers can be controlled manually or automatically. In manual control, an operator may look over his or her shoulder and manually adjust the tongue actuator to increase or reduce the amount of overlap. Such manual adjustment is not generally consistent or accurate and is tiresome for the operator. Automatic control may be based on, for example, global positioning satellite (GPS) coordinates of each of the mowers. While this is an effective way to control the overlap and underlap, several issues have been found with such systems. One particular issue that has been found is the overall complexity of the control system significantly increases when utilizing GPS coordinates, because each mower must be equipped with a GPS transponder and associated wiring and controls for the transponders. This increased complexity also increases the computing power that is required to control the overlap and underlap, which leaves less computing power available for other functions of the tractor. Further, utilizing GPS coordinates to control the overlap and underlap necessarily results in substantial adjustment delays, relative to real-time, due to travel time between the transponders and orbiting satellite(s), which can result in fairly large areas of underlap developing as the mowers travel at faster speeds.

To address some of the previously described issues, and referring now toFIG.2as well, the controller160is configured to determine a lateral overlap O or underlap of the first mower120and the second mower130, relative to the travel axis TA, exceeds a threshold value based at least partially on a steering angle Sα of the steerable axle115and the tongue angle α, determine a correction angle γ needed for the tongue133to pivot such that the lateral overlap O or underlap no longer exceeds the threshold value, and output a correction signal to the tongue actuator140to cause the tongue actuator140to pivot the tongue133by the correction angle γ. The controller160may determine the steering angle Sα, for example, based on signals output by the steering angle sensor117. The controller160may have a memory161that stores an algorithm for determining the correction angle γ that is needed to correct the overlap O or underlap based on the tongue angle α and the steering angle Sα. The algorithm may be derived from the geometric relationship between elements of the mowing system100, such as the driving vehicle110, the mowers120,130, and the tongue133coupling the second mower130to the driving vehicle110. In some embodiments, the controller160is configured to set a fixed relationship between the tongue angle α and the steering angle Sα, based on the algorithm, and determine the correction angle γ by determining an adjustment angle, i.e., an angle of adjustment, that is needed to maintain the fixed relationship between the tongue angle α and the steering angle Sα. It should be appreciated that many different types of algorithms may be used to determine the correction angle γ, depending on the geometry of the components of the mowing system100.

The threshold value for the lateral overlap O or underlap may be adjusted to many different values. In some embodiments, the threshold value for underlap is, for example, 1 cm while the threshold value for overlap is, for example, 5-10 cm. Due to any underlap resulting in standing plants being missed by the mowers120,130, the threshold value for underlap may be significantly smaller than the threshold value for overlap. In some embodiments, the threshold value for underlap is zero so that any determined underlap (subject to sensitivity of the measurement) causes the controller160to determine the correction angle γ and output the correction signal. The threshold value for overlap or underlap may be set by an operator manually or be an automatic preset value stored in the memory161of the controller160.

In some embodiments, the controller160is configured to determine the lateral overlap O or underlap exceeds the value at least partially by determining the lateral offset X between the driving vehicle110and the second mower130. As illustrated inFIG.1, the lateral offset X between the travel axis TA of the driving vehicle110/first mower120and the mowing axis MA of the second mower130provides a relative distance between edges of the mowers120,130. Using the known relationship between an edge of each mower120,130to its respective axis TA, MA and the lateral offset X, the controller160can determine the lateral overlap O or underlap. The lateral offset X may be determined, for example, from the tongue angle α and the steering angle Sα.

Referring specifically now toFIG.2, the steerable axle115defines a steerable axle axis SAA and the fixed axle116defines a fixed axle axis FAA, with a vehicle axle angle VA being defined between the steerable axle axis SAA and the fixed axle axis FAA. Similarly, the second mower130may include a mower axle132defining a mower axle axis MAA. In some embodiments, the controller160is configured to determine the lateral offset X during a turning maneuver by determining a lateral distance between a vertex V of the vehicle axle angle VA and the mower axle axis MAA. From this determined lateral offset X, the controller160can then determine the correction angle γ, as previously described.

It should be appreciated that while the previous description refers to determining the correction angle γ based at least partially on the steering angle Sα derived from signals output by the steering angle sensor117, the controller160can also be configured to determine the steering angle Sα in other ways. For example, in some embodiments the controller160is operatively coupled to a steering device, which may be controlled by the controller160, that is coupled to the steerable axle115and configured to adjust the steerable axle115to turn the driving vehicle110. Such devices are known, so further description is omitted for brevity. The controller160may be configured to follow a stored travel path, such as swath lines, and output steering signals to the steering device to cause the driving vehicle110to travel along the swath lines. The output steering signals may thus correspond to the steering angle Sα. In some embodiments, the controller160is configured to determine a turning maneuver is about to take place and determine a preemptive correction angle that will be needed to keep the lateral overlap O or underlap from exceeding the threshold value during the turning maneuver. In such an embodiment, the controller160can output a preemptive correction signal to the tongue actuator140that prepares the tongue actuator140to pivot the tongue133during the turning maneuver by, e.g., supplying pressurized fluid to the tongue actuator140. The preemptive correction signal can thus reduce the risk of delay occurring in keeping the lateral overlap O or underlap below the threshold value during a turning maneuver.

From the foregoing, it should be appreciated that the mowing system100provided according to the present disclosure includes a controller160that can control the lateral overlap O or underlap by determining a correction angle γ based on known vehicle geometry, which remains static, as well as the tongue angle α and the steering angle Sα, which are variable. Generally, the steering angle Sα is controlled to move the mowing system100in the proper direction, so the controller160can determine the correction angle γ for adjusting the tongue angle α so the mowers120,130maintain the proper amount of overlap and underlap. Unlike manual operation or known systems, which can rely on complicated GPS or crop sensor systems, the controller160provided according to the present disclosure only needs to know the tongue angle α and the steering angle Sα to determine the correction angle γ and keep the lateral overlap and underlap within the correct operating ranges. Such control represents an elegant solution that reduces the complexity of the system, and the associated costs and computing requirements, and is responsive in real-time to reduce the risk of excessive lateral overlap or underlap developing between the mowers120,130.

Referring now toFIG.3, an exemplary embodiment of a method300of controlling an agricultural mowing system100is illustrated. The method300is performed by a controller160and includes determining301a lateral overlap O or underlap of a first mower120and a second mower130, relative to a travel axis TA of a coupled driving vehicle110, exceeds a threshold value based at least partially on a steering angle Sα and a tongue angle α. The steering angle Sα and the tongue angle α may be determined from output signals from respective sensors117,150. Upon determining301that the lateral overlap O or underlap exceeds the threshold value, a correction angle γ is determined302, with the correction angle γ corresponding to an angle needed for a pivotable tongue133to pivot such that the lateral overlap O or underlap no longer exceeds the threshold value. A correction signal is output303to a tongue actuator140that causes the tongue actuator140to pivot the tongue133by the correction angle γ. Pivoting the tongue133by the correction angle γ adjusts the relative positioning of the mowers120,130to one another, adjusting the lateral overlap O or underlap.

The first mower120may be, for example, pushed in front of the driving vehicle110and the second mower130may be pulled by the driving vehicle110and connected to the tongue133. The threshold value for the lateral underlap may be 1 cm and the threshold value for the lateral overlap may be 25 cm, as previously described. The tongue actuator140and/or the tongue angle sensor150may be carried by a chassis111of the driving vehicle110.

In some embodiments, determining301the lateral overlap O or underlap exceeds the threshold value includes determining a lateral offset X between the driving vehicle110and one of the mowers, such as the second mower130. The lateral offset X may be determined during a turning maneuver by determining a lateral distance between a vertex V of a vehicle axis VA and a mower axle axis MAA, as previously described.

In some embodiments, the method further includes setting304a fixed relationship between the tongue angle α and the steering angle Sα. In such embodiments, determining302the correction angle γ can include determining an adjustment angle needed to maintain the fixed relationship between the tongue angle α and the steering angle Sα. It should be appreciated that determining302the correction angle γ can also be done in other ways, as previously described.

It is to be understood that the steps of the method300are performed by the controller160upon loading and executing software code or instructions which are tangibly stored on a tangible computer readable medium, such as on a magnetic medium, e.g., a computer hard drive, an optical medium, e.g., an optical disc, solid-state memory, e.g., flash memory, or other storage media known in the art. Thus, any of the functionality performed by the controller160described herein, such as the method300, is implemented in software code or instructions which are tangibly stored on a tangible computer readable medium. The controller160loads the software code or instructions via a direct interface with the computer readable medium or via a wired and/or wireless network. Upon loading and executing such software code or instructions by the controller160, the controller160may perform any of the functionality of the controller160described herein, including any steps of the method300described herein.