Implement guidance system and method

Abstract

A system includes a towing vehicle for towing an implement, an inclination sensor for determining a tilt of the towing vehicle, a positioning device for determining a position of the implement and an automated guidance system. The automated guidance system automatically operates the towing vehicle using positioning information from the positioning device so that the implement follows a wayline, detects a tilt of the towing vehicle using data from the inclination sensor and automatically operates the towing vehicle to make adjustments for a sloped ground surface based on the determined tilt of the towing vehicle so that the implement follows the wayline on the sloped ground surface. The system may also be configured to detect and compensate for an average implement crosstrack error resulting from, for example, implement settings.

Description

Docket No.: 25003 / WOIMPLEMENT GUIDANCE SYSTEM AND METHODFIELD

[0001] Embodiments of the present invention relate to the operation of mobile machines used in the agriculture and construction industries. More particularly, embodiments relate to a system and method for compensating for implement drift due to, for example, sloping ground surfaces and implement settings.BACKGROUND

[0002] In the agriculture and construction industries it is common to use a towing vehicle, such as a tractor, to pull an implement, such as a plow or a disc. It is also common for towing vehicles to include automated guidance systems that automatically control the towing vehicle to follow a predefined target path or “wayline”, thus eliminating the need for a human operator to constantly steer the vehicle.

[0003] When a towing vehicle pulls an implement along a sloped surface that causes sideways tilt or “roll” of the towing vehicle and implement, the implement may tend to slide downhill rather than follow directly behind the towing vehicle. This is referred to as implement drift or implement sidehill drift and can present a problem when using automated guidance because the automated guidance system operates the towing vehicle to maintain the vehicle centered on the target wayline but the implement ends up offset from the wayline. The steeper the incline and the greater the distance between the towing vehicle and a working portion of the implement, the more the implement tends to drift. Other factors that may influence implement drift include implement type and the nature of the work being performed.

[0004] The above section provides background information related to the present disclosure which is not necessarily prior art.Docket No.: 25003 / WOSUMMARY

[0005] A system according to an embodiment of the invention comprises a towing vehicle configured to tow an implement; an inclination sensor for determining a tilt of the towing vehicle; a positioning device for determining a position of the implement; and an automated guidance system for automatically operating the towing vehicle using positioning information from the positioning device so that the implement follows a wayline. The automated guidance system is configured to detect a tilt of the towing vehicle using data from the inclination sensor and automatically operate the towing vehicle to make adjustments for a sloped ground surface based on the determined tilt of the towing vehicle so that the implement follows the wayline on the sloped ground surface.

[0006] In some embodiments, the automated guidance system is configured to make the adjustments for the sloped ground surface by steering the tractor to follow a path that is uphill of the wayline such that the tractor begins following or moving toward the path while the implement is still on the wayline.

[0007] In some embodiments, the automated guidance system is configured to make the adjustments for the sloped ground surface according to an adjustment parameter and use positioning data from the positioning device to automatically change the adjustment parameter so that the implement follows the wayline on the sloped ground surface. The automated guidance system may be configured to use the positioning data to automatically change the adjustment parameter by detecting when the implement has overshot the wayline and changing the adjustment parameter so the towing vehicle reacts less aggressively to the tilt of the towing vehicle. The automated guidance system may be configured to use the positioning data to automatically change the adjustment parameter by detecting when the implement has undershot the wayline and changing the adjustment parameter so the towing vehicle reacts more aggressively to the tilt of the towing vehicle. The automated guidance system may be configured to automatically change the adjustment parameter according to a calibration value, the calibration value being derived from measured minimum and maximum implement crosstrack errors and a maximum measured roll value of the towing vehicle.

[0008] In some embodiments the system further comprises a user interface for receiving an input value from an operator, and the automated guidance system isDocket No.: 25003 / WOconfigured to make the adjustments for the sloped ground surface according to an adjustment parameter and change the adjustment parameter according to the input value. In some embodiments the automated guidance system is configured to detect an average implement crosstrack error using implement position information from the positioning device, and automatically operating the towing vehicle using the average implement crosstrack error so that the implement follows the wayline.

[0009] A method according to an embodiment of the invention comprises towing an implement with a towing vehicle; determining a tilt of the towing vehicle using a tilt sensor; determining a position of the implement using a positioning device located on the implement; automatically operating the towing vehicle, using an automated guidance system and positioning information from the positioning device, so that the implement follows a wayline; and automatically operating the towing vehicle, using the automated guidance system, to make adjustments for a sloped ground surface based on the determined tilt of the towing vehicle so that the implement follows the wayline on the sloped ground surface.

[0010] In some embodiments the method comprises making the adjustments for the sloped ground surface, using the automated guidance system, by steering the tractor to follow a path that is uphill of the wayline such that the tractor begins following or moving toward the path while the implement is still on the wayline. In some embodiments the method comprises making the adjustments for the sloped ground surface, using the automated guidance system, according to an adjustment parameter, and using positioning data from the positioning device and using the automated guidance system to automatically change the adjustment parameter so that the implement follows the wayline on the sloped ground surface.

[0011] In some embodiments the method comprises automatically changing, using the automated guidance system and the positioning data, the adjustment parameter by detecting when the implement has overshot the wayline and changing the adjustment parameter so the towing vehicle reacts less aggressively to the tilt of the towing vehicle. In some embodiments the method comprises automatically changing, using the automated guidance system and the positioning data, the adjustment parameter by detecting when the implement has undershot the wayline and changing the adjustment parameter so the towingDocket No.: 25003 / WOvehicle reacts more aggressively to the tilt of the towing vehicle. In some embodiments the method comprises automatically changing, using the automated guidance system, the adjustment parameter according to a calibration value, the calibration value being derived from measured minimum and maximum implement crosstrack errors and a maximum measured roll value of the towing vehicle.

[0012] In some embodiments the method comprises receiving an input value from an operator via a user interface and making the adjustments for the sloped ground surface, using the automated guidance system, according to an adjustment parameter and changing the adjustment parameter according to the input value. In some embodiments the method comprises using the automated guidance system to detect an average implement crosstrack error using implement position information from the positioning device and automatically operating the towing vehicle using the average implement crosstrack error so that the implement follows the wayline.

[0013] This summary is provided to introduce a selection of concepts in a simplified form that are further described in the detailed description below. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Other aspects and advantages of the present invention will be apparent from the following detailed description of the embodiments and the accompanying drawing figures.DRAWINGS

[0014] Embodiments of the present invention are described in detail below with reference to the attached drawing figures, wherein:

[0015] Fig 1 is a plan view of a tractor and implement in accordance with an embodiment of the invention.

[0016] Fig 2 is a schematic illustration of an electronic system of the tractor of Fig. 1.

[0017] Fig 3 illustrates a configuration of the electronic system of Fig. 2.

[0018] Fig 4 is the electronic system of Fig. 2 illustrating a portion of the system used in an automated guidance system.Docket No.: 25003 / WO

[0019] Fig 5 is a rear elevation view of the tractor of Fig. 1 illustrating the tractor operating on a sloped ground surface.

[0020] Fig 6 is a plan view of the tractor and implement of Fig. 1 operating on a sloped ground surface and illustrating implement drift.

[0021] Fig 7 is the tractor and implement of Fig. 6 illustrating travel paths of the tractor and the implement.

[0022] Fig 8 is the tractor and implement of Fig. 7, further illustrating an alternative path for the tractor that compensates for the implement drift.

[0023] Fig 9 illustrates the tractor and implement of Fig. 8 wherein the tractor is following the alternative path.

[0024] Fig 10 illustrates a portion of a user interface that is part of the electronic system of Fig. 2.

[0025] Fig 11 illustrates a path travelled by the implement of Fig. 1 without the use of implement drift compensation according to embodiments of the present invention.

[0026] Fig 12 illustrates a path travelled by the implement of Fig. 1 with the use of implement drift compensation according to embodiments of the present invention.

[0027] The drawing figures do not limit the present invention to the specific embodiments disclosed and described herein. The drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the invention.DESCRIPTION

[0028] The following detailed description of embodiments of the invention references the accompanying drawings. The embodiments are intended to describe aspects of the invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the spirit and scope of the invention as defined by the claims. The following description is, therefore, not to be taken in a limiting sense. Further, it will be appreciated that the claims are not necessarily limited to the particular embodiments set out in this description.

[0029] In this description, references to “one embodiment”, “an embodiment”, or “embodiments” mean that the feature or features being referred to are included in at leastDocket No.: 25003 / WOone embodiment of the technology. Separate references to “one embodiment”, “an embodiment”, or “embodiments” in this description do not necessarily refer to the same embodiment and are also not mutually exclusive unless so stated and / or except as will be readily apparent to those skilled in the art from the description. For example, a feature, structure, act, etcetera described in one embodiment may also be included in other embodiments, but is not necessarily included. Thus, the present technology can include a variety of combinations and / or integrations of the embodiments described herein.

[0030] When elements or components are referred to herein as being “connected” or “coupled,” the elements or components may be directly connected or coupled together or one or more intervening elements or components may also be present. In contrast, when elements or components are referred to as being “directly connected” or “directly coupled,” there are no intervening elements or components present.

[0031] Embodiments of the present invention address challenges associated with operating machines on sloped surfaces by reducing or eliminating the effects of implement drift and latency associated with implement drift compensation. According to some embodiments a system comprises a towing vehicle configured to tow an implement, an inclination sensor for determining a tilt of the towing vehicle, a positioning device for determining a position of the implement, and an automated guidance system. The automated guidance system is configured to automatically operate the towing vehicle using positioning information from the positioning device so that the implement follows a wayline. The automated guidance system is further configured to detect a tilt of the towing vehicle using data from the inclination sensor and automatically operate the towing vehicle to make adjustments for a sloped ground surface based on the determined tilt of the towing vehicle so that the implement follows the wayline on the sloped ground surface.

[0032] Thus, embodiments of the present invention address the problem of latency in implement drift compensation by detecting and responding to a tilt of the towing vehicle, rather than a tilt or crosstrack error of the implement. Because the towing vehicle encounters sloped ground surface before the implement, this technology allows the towing vehicle to anticipate implement drift and begin making adjustments for implement drift before the implement begins to drift, thus elimination or minimizing the effects of latency.Docket No.: 25003 / WO

[0033] Turning now to the drawing figures, and initially Fig. 1, a towing vehicle constructed in accordance with embodiments of the invention is illustrated. The illustrated towing vehicle is a tractor 10, and the tractor 10 is attached to and pulling an implement 12. The implement 12 is pivotally attached to a hitch 14 of the tractor 10. A working portion 16 of the implement 12 is separated from the tractor 10 by a distance 18, wherein the working portion 16 of the implement is a portion of the implement 12 that performs work, such as the portion of a tillage implement that engages the ground.

[0034] The tractor 10 and implement 16 include an electronic system 20 illustrated schematically in Fig. 2. The system 20 broadly includes a controller 22, a positioning system 24, a user interface 26, a plurality of sensors 28, one or more actuators 30, one or more storage components 32, one or more input / out ports 34, and a communications gateway 36.

[0035] The positioning system 24 uses one or more technologies to determine a location of the tractor 10, a location of the implement 12, or both. The positioning system 24 may include one or more global navigation satellite system (GNSS) receivers, such as GNSS receivers configured to receive signals from one or more positioning systems such as the United States’ global positioning system (GPS), the European GALILEO system, the Chinese Beidou system and / or the Russian GLONASS system, and to determine a location of the tractor 10 using the received signals. Alternatively or additionally, the positioning system 24 may use light detection and ranging (LiDAR) technology, radio detecting and ranging (RADAR) technology, one or more cameras, one or more inertial measurement units (IMUs), or a combination thereof to determine position or assist in determining position. As explained below, one or more components or portions of the positioning system 24 may be located on the tractor 10 to determine a location of the tractor 10 and one or more components of the positioning system 24 may be located on the implement 16 to determine a location of the implement 16. By way of example, a first GNSS receiver and a first IMU may be located on the tractor 10 and a second GNSS receiver and a second IMU may be located on the implement 16 to assist with guidance.

[0036] The user interface 26 includes components for receiving information, instructions or other input from a user and may include buttons, switches, dials, and microphones, as well as components for presenting information or data to users, such asDocket No.: 25003 / WOdisplays, light-emitting diodes, audio speakers and so forth. The user interface 26 may include one or more touchscreen displays capable of presenting visual representations of information or data and receiving instructions or input from the user via a single display surface.

[0037] The sensors 28 may be associated with any of various components or functions of the tractor 10 and / or the implement 12 including, for example, various elements of the engine, transmission(s), and hydraulic and electrical systems. As explained below, in some embodiments one or more of the sensors 28 is or includes an inclination sensor configured to determine a tilt of the tractor 10, and in some embodiments one or more of the sensors 28 is or includes an inclination sensor configured to determine a tilt of the implement 12. Furthermore, one or more of the sensors 28 may be configured and positioned to detect information about the environment in which the tractor 10 and implement 12 are operating including temperature, ambient light, objects external to the tractor 10 and a ground surface. The actuators 30 are configured and placed to drive certain functions of the tractor 10 and / or the implement 12 and may take virtually any form but are generally configured to receive control signals or instructions from the controller 22 (or other component of the system 20) and to generate a mechanical response to the control signals or instructions. By way of example, the sensors 28 and actuators 30 may be used in automated steering of the tractor 10 wherein the sensors 28 detect a current position or state of steered wheels and the actuators 30 drive steering action of the steered wheels.

[0038] The controller 22 is a computing device or system and includes one or more integrated circuits programmed or configured to implement the functions described herein and associated with the tractor 10 and / or the implement 12. By way of example, the controller 22 may be a digital controller and may include one or more general purpose microprocessors or microcontrollers, programmable logic devices, application specific integrated circuits or other computing or logic devices. The controller 22 may include multiple computing components, such as electronic control units, placed in various different locations on the tractor 10 and / or the implement 12, and may include one or more computing devices connected to the system 20 through the I / O port 34 and / or the gateway 36. The controller 22 may also include one or more discrete and / or analog circuit components operating in conjunction with the one or more integrated circuits or computingDocket No.: 25003 / WOcomponents. Furthermore, the controller 22 may include or have access to one or more memory elements (not illustrated) operable to store executable instructions, data, or both. The storage component 32 stores data and preferably includes a non-volatile storage medium such as solid state, optic or magnetic technology. The storage component 32 may store, for example, map information relating to a field in which the tractor 10 is operating or wayline information for use in automated guidance, as explained below in greater detail.

[0039] The communications gateway 36 includes one or more wireless transceivers configured to communicate with external systems, machines or devices using wireless communications technology. The communications gateway 36 may include one or more wireless transceivers configured to communicate according to one or more wireless communications protocols or standards, such as one or more protocols based on the IEEE 802.11 family of standards (“Wi-Fi”), the Bluetooth wireless communications standard, a 433 MHz wireless communications protocol or a protocol for communicating over a cellular telephone network. Alternatively or additionally, the communications gateway 36 may include one or more wireless transceivers configured to communicate according to one or more proprietary or non-standardized wireless communication technologies or protocols, such as proprietary wireless communications protocols using 2.4 GHz or 5 GHz radio signals. Thus, the communications gateway 36 enables wireless communications with other machines such as other harvesters or tractors, with external devices such as laptop or tablet computers or smartphones, and with external communications networks such as a cellular telephone network or Wi-Fi network.

[0040] An embodiment is illustrated in Fig. 3 wherein a first portion 20a of the electronic system 20 is located on the tractor 10 and a second portion 20b of the electronic system 20 is located on the implement 12. A first portion 24a of the positioning system 24 and a first one or more 28a of the sensors 28 are located on the tractor 10. The first portion 24a of the of the positioning system 24 is located on the tractor 10 for detecting and tracking a location of the tractor 10 and may include, for example, a GNSS receiver and / or an inertial measurement unit. The first one or more sensors 28a includes at least a tilt sensor for detecting an inclination of the tractor 10. A second portion 24b of the positioning system 24 and a second one or more 28b of the sensors 28 are located on the implement 12. The second portion 24b of the of the positioning system 24 is located on the implement 12 forDocket No.: 25003 / WOdetecting and tracking a location of the implement 12 and may include, for example, a GNSS receiver and / or an inertial measurement unit. The second one or more sensors 28b includes at least a tilt sensor for detecting an inclination of the implement 12. It will be appreciated that the first portion 24a and the second portion 24b of the positioning system 24 may include any of various positioning devices for determining location including devices that use camera technology. Furthermore, some of the components of the system 20 may be combined such that the functionality is implemented in a single unit. Inertia and inclination measurements may be performed by a single device, for example, such as an inertial measurement unit (IMU) configured to detect both. Thus, while the embodiment illustrated in Fig. 3 is described as having an IMU sensor and a tilt sensor, it will be appreciated that those may be separate devices or may be integrated into a single device and that both implementations are within the ambit of the present invention. The dashed line connecting the first portion 20a of the electronic system 20 located on the tractor 10 with the second portion 20b of the electronic system 20 located on the implement 12 represents a communications medium for enabling communications between the components of the first portion 20a and the components of the second portion 20b. In some embodiments the communications medium is a wired communications medium using the CANBUS communication protocol. Other technologies may be used, including wireless communications mediums and protocols.

[0041] It will be appreciated that, for simplicity, certain elements and components of the system 20 have been omitted from the present discussion and from the diagram illustrated in Fig. 2. A power source or power connector and a data communications medium are also associated with the system 20, for example, but are conventional in nature and, therefore, is not discussed herein.

[0042] The tractor 10 and / or the implement 12 include an automated guidance system capable of automatically operating the tractor 10 so that the tractor 10 and / or the implement 12 follow a target path known as a wayline. With reference to Fig. 4, an exemplary automated guidance system 37 is included in, or implemented by, the electronic system 20 using, for example, the controller 22, the storage component 32, the positioning system 24, the user interface 26, at least one of the sensors 28 and at least one of the actuators 30. The automated guidance system 37 may use the user interface 26 to receiveDocket No.: 25003 / WOinformation from a user such as a width of the implement 12 attached to the tractor 10, selection or definition of a wayline, commands to engage and disengage automated guidance and / or to receive an adjustment parameter, as discussed below.

[0043] Automated guidance of a machine involves generating a wayline, determining a location of the machine relative to the wayline and automatically steering the machine to follow the wayline. While the machine travels along the wayline the automated guidance system continuously detects the machine’s position using the positioning system 24 and compares it to the location of the wayline. The system 37 identifies discrepancies between the machine’s position and the location of the way line as crosstrack errors. If the machine is ten centimeters to the left of the wayline the crosstrack error is ten centimeters and the guidance system 37 corrects the error by steering the machine toward the right ten centimeters. The wayline may be generated by an operator of the machine by, for example, designating a starting point and an ending point of the wayline or designating a starting point and a direction of travel. The wayline may be generated in its entirety all at once or may be generated by sensors that allow adaptive guidance based on the current environment and task. The wayline may also be stored and retrieved from a previous operation, received from another agricultural machine or imported from an external computing device, such as an external computer running farm management software that generates the wayline.

[0044] The automated guidance system 37 is part of the tractor 10 and / or the implement 12 and is included in the electronic system 20 as described above. Automated guidance software stored in the storage component 32, for example, enables the controller 22 to determine or acquire the wayline, determine the location of the tractor 10 and / or the implement 12 using the position system 24, compare the tractor’s and / or the implement’s location with the location of the wayline, and automatically steer the tractor 10 using data from the one or more sensors 28 to determine a steering angle of the steerable wheels and using the one or more actuators 30 to change the steering angle of the wheels, if necessary, to steer the machine to or along the wayline. During operation the location of the tractor 10 and / or the implement 12 is continuously determined using the positioning system 24, and the location of a navigation point of the tractor 10 (for example, a point located between rear wheels of the tractor 10) and / or the implement 12 (for example, a point located at theDocket No.: 25003 / WOcenter of the implement 12) is continuously compared with the location of the wayline. Steering of the tractor 10 is automatically controlled so that the navigation point follows the wayline.

[0045] Embodiments of the invention relate to an implement guidance system wherein the tractor 10 is operated to pull the implement 12 so that the implement 12, and not the tractor 10, follows a wayline. This embodiment includes the electronic system 20 as configured in Fig. 3 with a first portion 20a of the system 20 located on the tractor 10 and a second portion 20b of the system 20 located on the implement 12 as illustrated in Fig. 3. The automated guidance system 37 determines the location of the implement 12 relative to the wayline using a GNSS receiver and / or IMU (or other positioning device or devices, as explained above) that is part of the positioning system 24b and controls operation of the tractor 10 so that the implement 12 follows the wayline. The guidance system 37 continuously or periodically detects the location of the implement 12 relative to the wayline and determines whether there is a difference between the location of the implement 12 and the wayline, referred to as a crosstrack error. If the guidance system 37 determines that the implement 12 is to the left of the target wayline it controls the tractor 10 to move toward the right, thus moving the implement 12 toward the right and back toward the wayline. If the guidance system 37 determines that the implement 12 is to the right of the target wayline it controls the tractor 10 to move toward the left, thus moving the implement 12 toward the left and back toward the target wayline.

[0046] The automated guidance system 37 is configured to compensate for implement drift resulting from the tractor 10 and the implement 12 operating on a sloped surface. With particular reference to Figs. 5 and 6, the tractor 10 is illustrated operating on a ground surface 50 with a slope of 0 degrees such that the tractor 10 and implement 12 are tilted laterally by 0 degrees toward the left in Fig. 5 and in the direction of the arrow 52 in Fig. 6. For simplicity of illustration the implement 12 is omitted from Fig. 5. A problem associated with implement drift is illustrated in Fig. 7, wherein the tractor 10 does not follow the same path as the tractor 10. If the tractor 10 is steered to follow the wayline 54 the implement follows a path 56 separated downhill from the wayline 54 and therefore does not work the desired area of land. If not addressed, this implement drift results in overlapping swaths on one side and / or a gap between swaths on the other side.Docket No.: 25003 / WO

[0047] Using an implement guidance system wherein the implement 12 includes a positioning device such as a GNSS receiver and / or an IMU to determine a location of the implement 12, the guidance system 37 compensates for the implement drift depicted in Fig. 7 resulting from a sloping ground surface by causing the tractor 10 to move uphill, or to the right in Fig. 7. With reference to Fig. 8, the tractor 10 is following a path 54 corresponding to the wayline while the implement 12, which has drifted downhill, is following the path 56 that is generally parallel with, but separated from, the path 54. To correct this problem and place the implement 12 back on the wayline 54 the guidance system 37 steers the tractor 10 to follow a path 72 that is generally parallel with and uphill from the target wayline 54. As illustrated in Fig. 9, when the tractor 10 follows the path 72 the implement 12 follows the wayline 54.

[0048] While use of an implement guidance system with a positioning device on the implement 12 addresses the problem of implement drift there remains the problem of latency associated with the tractor 10 responding to crosstrack errors detected using positioning devices of the positioning system 24b on the implement. When the guidance system 37 detects crosstrack error of the implement 12 the implement 12 has already begun to drift off the wayline. It takes time for the tractor 10 to move to a different location and it takes the implement 12 even longer to move because the implement’s lateral movements lag behind those of the tractor. With reference to Fig. 8, the ground surface may begin to slope at point 90 but by the time the guidance system 37 detects a crosstrack error using position information from a positioning device on the implement 12 and begins to react the tractor 10 may be at point 92 before it begins to correct the crosstrack error of the implement 12. This results in the implement 12 being off the way line 54 for at least a short distance each time there is a change in the slope of the ground surface.

[0049] To avoid the problems associated with the latency of the tractor’s response to the crosstrack error the guidance system 37 implements anticipatory correction. With continued reference to the scenario illustrated in Fig. 8, the inclination sensor 28a on the tractor detects tilt of the tractor 10 when the tractor first begins to tilt at point 90. When the tractor 10 is beginning to tilt at point 90 the implement 12 has not begun to drift. By the time the implement 12 reaches point 90 where drifting is likely to begin the tractor 10 has moved to path 72 so that the implement 12 remains on the target wayline 54.Docket No.: 25003 / WO

[0050] The guidance system 37 may be configured to react to measured tilt of the tractor 10 according to an adjustment parameter. A first example of an adjustment parameter may be five centimeters per degree, wherein for every degree of tilt measured at the tractor 10 the guidance system adjusts the tractor’s travel path uphill by five centimeters. If the guidance system 37 determines that this adjustment parameter is not aggressive enough and that the implement 12 is still downhill of the target path 54, the guidance system 37 may increase the adjustment parameter to, for example, seven centimeters per degree of tilt. Similarly, if the guidance system 37 determines that this adjustment parameter is too aggressive and that the implement 12 is uphill of the target path 54, the guidance system 37 may decrease to the adjustment parameter to, for example, three centimeters per degree of tilt.

[0051] The adjustment parameter may be at least partially manually submitted by a user via the user interface 26. An exemplary element of the user interface 26 is illustrated in Fig. 10, wherein the element includes a slider 38 that a user can manipulate to indicate an adjustment parameter. If the user positions a marker 40 at the left end 42 the parameter is a minimum value, if the user positions the marker 40 at the right end 44 the parameter is a maximum value. In the exemplary user interface element illustrated in Fig. 10 the marker 40 is positioned at a point on the slider 38 corresponding to thirty-six percent of the distance between the left end 42 and the right end 44 such that the adjustment parameter will be thirty-six percent of the maximum value. The current adjustment parameter percentage (thirty-six percent in the user interface illustrated in Fig. 10) is visually indicated at or on the marker 40 and near the right end 44. A first icon 46 is located near the left end 42 of the slider 38 indicating the minimum adjustment parameter with a depiction of a tractor on a wayline. A second icon 48 is located near the right end 44 of the slider 38 indicating the maximum adjustment parameter with a depiction of a tractor off a wayline.

[0052] By way of example and not limitation, the minimum adjustment parameter may be between zero and five centimeters per degree of tilt and the maximum tilt adjustment parameter may be between ten and fifty centimeters per degree of tilt. Some exemplary tilt adjustment parameters include five centimeters, ten centimeters, fifteen centimeters, twenty centimeters and twenty-five centimeters per degree of tilt.Docket No.: 25003 / WO

[0053] The guidance system 37 may automatically change the adjustment parameter according to equation (1) to guide the tractor 10 so that the implement 12 more accurately follows the wayline 54:whereinOffsetLateral is the distance the tractor 10 deviates or shifts from the wayline to compensate for implement drift,Roll Angle is the roll angle of the tractor 10,Slideruanuai is the setting of the slider 38 (if used), andCalibration is a calibration value automatically determined by the system 37. The adjustment parameter of equation (1 ) is the fraction to the right of Roll Angle. In some embodiments the system 37 may not receive a manual slider input from the operator via the slider 38. In those embodiments the variable Slideruanuai is set to zero in equation (1).

[0054] The calibration value Calibration represents a correction for detected errors in the implement drift compensation associated with sloping terrain. The system 37 detects errors in the implement drift compensation by tracking the implement’s crosstrack errors and the tractor’s roll angle. More particularly, the calibration value Calibration is an average of the variable ASlider, defined according to equation (2):AxtrackASlider =rolljnax (2)whereinAxtrack is the difference between an average of the largest leftmost crosstrack errors and an average of the largest rightmost crosstrack errors detected by the system 37, androll max is an average of the largest roll angles of the tractor.

[0055] The system 37 may calculate the variable Axtrack by storing a number, such as ten, fifteen or twenty, of the highest leftmost and rightmost crosstrack error values,Docket No.: 25003 / WOwherein the leftmost crosstrack error values represent the crosstrack errors furthest to the left (toward the top of Fig. 11) and the rightmost crosstrack error values represent the crosstrack errors furthest to the right (toward the bottom of Fig. 11). The value of Axtrack is the difference between the average of the highest leftmost crosstrack error values and the average of the highest rightmost crosstrack error values. This is illustrated in Fig. 11, wherein an actual path 100 followed by the implement 12 includes swings toward the left (toward the top of the figure) and toward the right (toward the bottom of the figure). The top line 102 represents the average of the highest leftmost crosstrack error values represented by the “x” indicators nearest line 102. The bottom line 104 represents the average of the highest rightmost crosstrack error values represented by the “x” indicators nearest line 104. The value of Axtrack is calculated as the difference between the averaged highest leftmost crosstrack error values and the averaged highest rightmost crosstrack error values, or the difference between lines 102 and 104. It should be noted that the leftmost crosstrack errors and the rightmost crosstrack errors may be on opposite sides of the wayline or may both be on the same side of the wayline. Both the leftmost crosstrack errors and the rightmost crosstrack errors may be on the left side of the wayline, for example, or both may be on the right side of the wayline. The system 37 calculates roll max as an average of the highest roll values of the tractor 10 detected over the same path 100 where the Axtrack was calculated.

[0056] By automatically calculating and using the adjustment parameter Offset Lateral in drift compensation the system 37 eliminates or minimizes drift compensation errors that result in implement crosstrack errors. Figure 12 illustrates the path followed by the implement 12 on the same pass as Fig. 11 but with the adjustment parameter OffsetLaterai used to correct the implement drift compensation. As can be seen from Figs. 11 and 12, the crosstrack errors of the implement 12 are significantly smaller when the adjustment parameter OffsetLaterai is used to correct the implement drift compensation. It will be appreciated that while Fig. 12 illustrates a path with reduced crosstrack error this technology may entirely eliminate crosstrack errors in some applications.

[0057] The system 37 may also detect and compensate for an average implement crosstrack error occurring during normal operation of the implement on level ground and resulting from such things as implement settings or the nature of the implement that causeDocket No.: 25003 / WOthe implement 12 to follow the tractor 10 somewhat to the right or left of the wayline. The system 37 detects the average crosstrack error as an overall average implement crosstrack error regardless of ground surface slope. Adding the average implement crosstrack error to the equation (1) results in the following:wherein CXTrack is a parameter used to adjust the average implement crosstrack error. In some embodiments, for example, CXTrack is the raw value of the average implement crosstrack error. In other embodiments CXTrack is the raw value of the average implement crosstrack error multiplied by a constant value such as 0.25, 0.5, 0.75 or 1.25. These are just a few examples.

[0058] Although the invention has been described with reference to the preferred embodiment illustrated in the attached drawing figures, it is noted that equivalents may be employed and substitutions made herein without departing from the scope of the invention as recited in the claims.

[0059] The claims at the end of this patent application are not intended to be construed under 35 U.S.C. § 112(f) unless traditional means-plus-function language is expressly recited, such as “means for” or “step for” language being explicitly recited in the claim(s).

[0060] Having thus described the preferred embodiment of the invention, what is claimed as new and desired to be protected by Letters Patent includes the following:

Claims

Docket No.: 25003 / WOCLAIMS1. A system comprising:a towing vehicle configured to tow an implement;an inclination sensor for determining a tilt of the towing vehicle;a positioning device for determining a position of the implement; andan automated guidance system for automatically operating the towing vehicle using positioning information from the positioning device so that the implement follows a wayline, the automated guidance system configured to detect a tilt of the towing vehicle using data from the inclination sensor and automatically operate the towing vehicle to make adjustments for a sloped ground surface based on the determined tilt of the towing vehicle so that the implement follows the wayline on the sloped ground surface.

2. The system as set forth in claim 1, the automated guidance system configured to make the adjustments for the sloped ground surface by steering the tractor to follow a path that is uphill of the wayline such that the tractor begins following or moving toward the path while the implement is still on the wayline.

3. The system as set forth in either claim 1 or claim 2, the automated guidance system configured to - make the adjustments for the sloped ground surface according to an adjustment parameter, anduse positioning data from the positioning device to automatically change the adjustment parameter so that the implement follows the wayline on the sloped ground surface.

4. The system as set forth in claim 3, the automated guidance system configured to use the positioning data to automatically change the adjustment parameter by detecting when the implement has overshot the wayline and changing the adjustment parameter so the towing vehicle reacts less aggressively to the tilt of the towing vehicle.Docket No.: 25003 / WO5. The system as set forth in claim 3, the automated guidance system configured to use the positioning data to automatically change the adjustment parameter by detecting when the implement has undershot the wayline and changing the adjustment parameter so the towing vehicle reacts more aggressively to the tilt of the towing vehicle.

6. The system as set forth in claim 3, the automated guidance system configured to automatically change the adjustment parameter according to a calibration value, the calibration value being derived from measured minimum and maximum implement crosstrack errors and a maximum measured roll value of the towing vehicle.

7. The system as set forth in any preceding claim,further comprising a user interface for receiving an input value from an operator, the automated guidance system configured to make the adjustments for the sloped ground surface according to an adjustment parameter and change the adjustment parameter according to the input value.

8. The system as set forth in any preceding claim, the automated guidance system configured to - detect an average implement crosstrack error using implement position information from the positioning device, andautomatically operating the towing vehicle using the average implement crosstrack error so that the implement follows the wayline.Docket No.: 25003 / WO9. A method comprising:towing an implement with a towing vehicle;determining a tilt of the towing vehicle using a tilt sensor;determining a position of the implement using a positioning device located on the implement;automatically operating the towing vehicle, using an automated guidance system and positioning information from the positioning device, so that the implement follows a wayline; andautomatically operating the towing vehicle, using the automated guidance system, to make adjustments for a sloped ground surface based on the determined tilt of the towing vehicle so that the implement follows the wayline on the sloped ground surface.

10. The method as set forth in claim 9, further comprising making the adjustments for the sloped ground surface, using the automated guidance system, by steering the tractor to follow a path that is uphill of the wayline such that the tractor begins following or moving toward the path while the implement is still on the wayline.

11. The method as set forth in either claim 9 or claim 10, further comprising - make the adjustments for the sloped ground surface, using the automated guidance system, according to an adjustment parameter, andusing positioning data from the positioning device, using the automated guidance system, to automatically change the adjustment parameter so that the implement follows the wayline on the sloped ground surface.

12. The method as set forth in claim 11, further comprising automatically changing, using the automated guidance system and the positioning data, the adjustment parameter by detecting when the implement has overshot the wayline and changing the adjustment parameter so the towing vehicle reacts less aggressively to the tilt of the towing vehicle.Docket No.: 25003 / WO13. The method as set forth in claim 11, further comprising automatically changing, using the automated guidance system and the positioning data, the adjustment parameter by detecting when the implement has undershot the way line and changing the adjustment parameter so the towing vehicle reacts more aggressively to the tilt of the towing vehicle.

14. The method as set forth in claim 11, further comprising automatically changing, using the automated guidance system, the adjustment parameter according to a calibration value, the calibration value being derived from measured minimum and maximum implement crosstrack errors and a maximum measured roll value of the towing vehicle.

15. The method as set forth in any of claims 9 through 14, further comprising - receiving an input value from an operator via a user interface; andmaking the adjustments for the sloped ground surface, using the automated guidance system, according to an adjustment parameter and changing the adjustment parameter according to the input value.

16. The method as set forth in any of claims 9 through 15, further comprising using the automated guidance system to - detect an average implement crosstrack error using implement position information from the positioning device, andautomatically operating the towing vehicle using the average implement crosstrack error so that the implement follows the wayline.

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