COORDINATED CONTROL OF STEERABLE ATTACHMENTS

Description

TECHNICAL FIELD

The embodiments described herein are generally directed to coordinated control attachments, and, more particularly, to the coordinated control of steerable attachments in a work machine.

BACKGROUND

Motor graders are used to flatten a surface during grading projects, and can also be used for other tasks (e.g., snow removal, mixing and spreading materials, etc.). However, a large motor grader may not be suitable for all tasks, such as those in tight spaces, on rough terrain, using novice operators, and/or the like.

In these cases, a grader attachment may be affixed to the front of a skid steer, wheel loader, or other work machine. The attachment will generally comprise a fastening portion, configured to be attached to the front of the work machine, at one end, caster wheels at the opposite end, and a blade, also referred to as a moldboard, between the opposing ends. The blade is configured to flatten a surface, remove materials, mix and spread materials, and the like.

Work machines with such attachments may face challenges. In particular, the caster wheels on the attachment offer no lateral resistance to the lateral forces generated by the blade when the blade is yawed or unevenly loaded. These lateral forces may cause the caster wheels to lose traction, leading to difficulties in maintaining a consistent grading depth and achieving the desired smoothness in road construction or maintenance projects.

Accordingly, a steerable attachment would offer a variety of benefits. Steerable attachments have been used in other contexts. For example, U.S. Pat. No. 9,062,940 describes an example of a steerable attachment that is used for mine detonation. However, while a steerable attachment can provide the necessary lateral resistance for grading operations, a work machine, such as a skid steer, is generally capable of a tighter turn radius than the steerable attachment. If the work machine attempts a turn that is not within the capability of the steerable attachment, the steerable attachment may lose traction. The present disclosure is directed toward a steerable attachment, in the context of grading and similar tasks, that overcomes this and other problems discovered by the inventors.

SUMMARY

In an embodiment, a steerable attachment comprises: an attachment body, wherein the attachment body comprises a fastening portion, and wherein the fastening portion is configured to attach to a work machine; a blade connected to the attachment body and configured to flatten a surface; at least one ground-engaging member; a steerable axle system connected to the attachment body and configured to steer and rotate the at least one ground-engaging member; and an attachment electronic control module configured to receive one or more steering commands from a machine electronic control module in the work machine, actuate the steerable axle system according to the one or more steering commands, measure a position of the steerable axle system, calculate a steering radius of the steerable axle system based on the measured position, and send the calculated steering radius to the machine electronic control module.

In an embodiment, a steerable attachment comprises: an attachment body, wherein the attachment body comprises a fastening portion, and wherein the fastening portion is configured to attach to a work machine; a blade connected to the attachment body and configured to flatten a surface, wherein the blade is joined to the attachment body along a central axis, and configured to rotate around the central axis; at least one ground-engaging member; a steerable axle system connected to the attachment body and configured to steer and rotate the at least one ground-engaging member, wherein the steerable axle system comprises at least one all-wheel drive hub, and wherein the at least one ground-engaging member is driven by the at least all-wheel drive hub; and an attachment electronic control module configured to receive one or more steering commands from a machine electronic control module in the work machine, actuate the steerable axle system according to the one or more steering commands, measure a position of the steerable axle system, calculate a steering radius of the steerable axle system based on the measured position, and send the calculated steering radius to the machine electronic control module.

In an embodiment, a method of controlling an steerable attachment that is attached to a work machine, comprises: by a machine electronic control module in the work machine, receiving a steering control from one or more machine controls in the work machine, sending one or more steering commands to an attachment electronic control module in the steerable attachment based on the steering control, receiving a steering radius from the attachment electronic control module, and matching a steering radius of the work machine to the received steering radius; and by the attachment electronic control module in the steerable attachment, receiving the one or more steering commands from the machine electronic control module, actuating a steerable axle system of the steerable attachment according to the one or more steering commands, measuring a position of the steerable axle system, calculating a steering radius of the steerable axle system based on the measured position, and sending the calculated steering radius to the machine electronic control module.

BRIEF DESCRIPTION OF THE DRAWINGS

The details of embodiments of the present disclosure, both as to their structure and operation, may be gleaned in part by study of the accompanying drawings, in which like reference numerals refer to like parts, and in which:

FIG. 1 illustrates a side view of a work machine with a steerable attachment, according to an embodiment;

FIG. 2 illustrates a top-down schematic of a steerable attachment for a work machine, according to an embodiment;

FIG. 3 illustrates a schematic of a steerable axle system in isolation, according to an embodiment;

FIG. 4 illustrates a process for steering control, according to an embodiment;

FIG. 5 illustrates a process for actuating a steerable axle system, according to an embodiment; and

FIG. 6 illustrates an example of a controller, according to an embodiment.

DETAILED DESCRIPTION

The detailed description set forth below, in connection with the accompanying drawings, is intended as a description of various embodiments, and is not intended to represent the only embodiments in which the disclosure may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the embodiments. However, it will be apparent to those skilled in the art that embodiments of the invention can be practiced without these specific details. In some instances, well-known structures and components are shown in simplified form for brevity of description. In addition, it should be understood that the various components illustrated herein are not necessarily drawn to scale. In other words, the features disclosed in various embodiments may be implemented using different relative dimensions within and between components than those illustrated in the drawings.

FIG. 1 illustrates a side view of a work machine 100 with a steerable attachment 200, according to an embodiment. Work machine 100 is illustrated as a skid steer, and particularly, a compact track loader. Examples of compact track loaders include the Models 239, 349, 359, 255, 265, 279, 289, and 299 of compact track loaders, offered by Caterpillar Inc. of Irving, Texas. Work machine 100 could also be a skid steer loader, such as Models 226, 232, 236, 242, 246, 262, and 272 of skid steer loaders, offered by Caterpillar Inc. More generally, work machine 100 may be any type or model of equipment that can use steerable attachment 200, for instance, in an industrial site in which construction, mining, agriculture, forestry, paving, and/or the like are performed. Work machine 100 may be operated by a human (e.g., locally or remotely) or by an autonomous system. In addition, work machine 100 may be powered by an internal combustion engine and/or may be electrically powered by an on-board battery pack.

Work machine 100 may comprise a machine body 110. Machine body 110 may comprise a sturdy frame that supports the cabin, engine, transmission, battery pack, actuators, and/or other components of work machine 100.

Machine body 110 may support a pair of loader arms 120. Loader arms 120 may be raised and lowered via a hydraulic system. The hydraulic system may comprise a cylindrical housing and a piston that extends out of and retracts into the cylindrical housing, according to hydraulic pressure applied to the piston. Alternatively, loader arms 120 may be raised and lowered and/or otherwise manipulated via a different actuating mechanism.

Loader arms 120 are configured to be equipped with a standard work implement. In the case that work machine is a skid steer or wheel loader, this standard work implement may be a bucket for digging, scraping, lifting, carrying, or otherwise moving material. In the illustrated embodiment, the bucket or other standard work implement has been removed, and loader arms 120 have been equipped with steerable attachment 200, as discussed elsewhere herein. In an alternative embodiment, work machine 100 may comprise a different mechanism from loader arms 120 for attaching steerable attachment 200.

Work machine 100 may comprise at least one, and generally a plurality of, ground-engaging members 130. Ground-engaging members 130 are illustrated as a track or pair of tracks. In an alternative embodiment, ground-engaging members 130 may comprise wheels with tires. More generally, ground-engaging member(s) 130 may comprise any mechanism for supporting work machine 100 above the ground, and preferably moving work machine 100 relative to the ground.

Work machine 100 may comprise one or more machine controls 140. Machine control(s) 140 may be designed to provide a local operator, remote operator, or autonomous system command over the various functions of work machine 100, including turning work machine 100 on and off, steering work machine 100, increasing and decreasing the speed of work machine 100, raising and lowering loader arms 120, and/or the like. Machine control(s) 140 can be housed within the cabin of work machine 100, in which case machine control(s) 140 may be designed for use by a local operator. In this case, machine control(s) 140 may include one or more joysticks, a steering wheel, one or more pedals, one or more levers, and/or the like, which control various functions of work machine 100. Alternatively or additionally, work machine 100 may comprise electronic interfaces (e.g., touchscreen console(s)) that enable the local operator to access various functions of work machine 100 and/or provide real-time information about the operation of work machine 100. In an embodiment, machine control(s) 140 may also provide command over one or more functions of steerable attachment 200.

Work machine 100 may comprise a machine electronic control module (ECM) 150. It should be understood that the illustrated position of machine electronic control module 150 is merely representative, and that the actual position of machine electronic control module 150 may be any suitable location on or within machine body 110. Machine electronic control module 150 may be configured to receive commands from machine control(s) 140, calculate one or more control parameters from these commands, and utilize the control parameters to actuate one or more components of work machine 100, such as loader arms 120 and ground-engaging members 130. The control parameter(s) may comprise a turn radius of ground-engaging members 130 (e.g., tracks) and/or a differential speed between the pair of ground-engaging members 130. In an embodiment, machine electronic control module 150 is further configured to utilize the control parameters to actuate one or more components of steerable attachment 200, coordinate turning with steerable attachment 200, and/or the like, as will be discussed elsewhere herein.

Steerable attachment 200 may comprise an attachment body 210 with a fastening portion 215. Fastening portion 215 is configured to fasten to work machine 100, so as to attach steerable attachment 200 to work machine 100. For example, fastening portion 215 may be configured to be secured to loader arms 120. In an embodiment, fastening portion 215 utilizes the same fastening mechanism as the standard work implement that work machine 100 utilizes. In the case of a skid steer or wheel loader, fastening portion 215 may comprise a pair of engagement members, that are identical or similar to the engagement members on the bucket. Each engagement member may be configured to connect to the front end of a respective one of the pair of loader arms 120, via one or more pins, screws, bolts, and/or the like.

Steerable attachment 200 may comprise one or more ports or cables that connect to corresponding cables or ports on work machine 100, through fastening portion 215. These physical connections may be used for communications between work machine 100 and steerable attachment 200 and/or for supplying power and/or hydraulic fluid from work machine 100 to components of steerable attachment 200. In a particular implementation, a 14-pin connector is used to electronically connect steerable attachment 200 to work machine 100.

Steerable attachment 200 may comprise a blade 220, which may also be referred to as a moldboard. It should be understood that blade 220 serves as the primary tool for grading and other tasks. Blade 220 is positioned below attachment body 210 and connected to attachment body 210. Blade 220 may be configured to pivot (roll), relative to attachment body 210, within a range of angles around a horizontal longitudinal axis X that bisects blade 220. Blade 220 may also be configured to pivot (yaw), relative to attachment body 210, within a range of angles around a vertical central axis Y that bisects blade 220. Blade 220 may also be configured to pivot (pitch), relative to attachment body 210, within a range of angles around a horizontal lateral axis Z through blade 220. In each case, blade 220 may be pivoted by one or more hydraulic systems. Each hydraulic system may comprise a cylindrical housing and a piston that extends out of and retracts into the cylindrical housing, according to hydraulic pressure applied to the piston, to thereby push or pull an end of blade 220 around the respective axis. In an alternative embodiment, steerable attachment 200 may comprise a different mechanism for pivoting blade 220 around longitudinal axis X, central axis Y, or lateral axis Z. Blade 220 may also be configured to be raised or lowered, relative to attachment body 210, within a range of distances along vertical central axis Y. Thus, blade 220 can be angled, tilted, raised, and/or lowered to move, cut, and/or otherwise shape materials. Different types of blade 220 may be swapped in or out of steerable attachment 200, such as straight blades for general grading and V-shaped blades for cutting through tough materials.

Steerable attachment 200 may comprise a steerable axle system 300 at the opposite end of attachment body 210 as fastening portion 215. Steerable axle system 300, which will be described in further detail elsewhere herein, may drive at least one, and preferably a pair of, ground-engaging members 230 on either side of steerable axle system 300. Each ground-engaging member 230 may comprise a wheel with a tire.

Steerable attachment 200 may comprise an attachment electronic control module 250. It should be understood that the illustrated position of attachment electronic control module 250 is merely representative, and that the actual position of attachment electronic control module 250 may be any suitable location on or within attachment body 210. Attachment electronic control module 250 may be configured to control one or more components of steerable attachment 200, including blade 220 and/or steerable axle system 300. Of particular relevance to disclosed embodiments, attachment electronic control module 250 may be configured to receive steering commands from machine electronic control module 150 in work machine 100, actuate steerable axle system 300 according to the steering commands, measure the position of steerable axle system 300, calculate a steering radius of steerable axle system 300 based on the measured position, and send the calculated steering radius to machine electronic control module 150 to coordinate the turning of ground-engaging member(s) 230 of steerable attachment 200 with the turning of ground-engaging member(s) 130 of work machine 100. In this case, the steering commands may comprise a turn radius of ground-engaging members 130 (e.g., two tracks) and/or a differential speed between ground-engaging members 130 of work machine 100. In addition, attachment electronic control module 250 may be configured to receive control parameters for actuating blade 220 (e.g., to rotate around axes X, Y, and/or Z) from machine electronic control module 150, and actuate blade 220 according to the control parameter(s). Alternatively, blade 220 could be actuated by direct hydraulic control through machine electronic control module 150.

Attachment electronic control module 250 may be configured to communicate with machine electronic control module 150 (e.g., to receive steering commands and/or other control parameters, send the calculated steering radius, etc.) via a wired connection. For example, one or more cables may be run from attachment electronic control module 250, through the interface between fastening portion 215 and work machine 100, to machine electronic control module 150. Alternatively or additionally, attachment electronic control module 250 may be configured to communicate with machine electronic control module 150 via wireless communication. For example, attachment electronic control module 250 may comprise a wireless receiver or transceiver, and machine electronic control module 150 may comprise a wireless transmitter or transceiver that is configured to communicate with the wireless receiver or transceiver of attachment electronic control module 250 via a standard or non-standard wireless communication protocol.

FIG. 2 illustrates a top-down schematic of a steerable attachment 200 for a work machine 100, according to an embodiment. As described above, steerable attachment 200 may comprise an attachment body 210 with a fastening portion 215, a blade 220 that is configured to pivot around axes X, Y, and/or Z under the control of attachment electronic control module 250 or machine electronic control module 150, and one or more ground-engaging members 230 (e.g., one or two wheels) that can be steered and driven by steerable axle system 300.

FIG. 3 illustrates a schematic of a steerable axle system 300 in isolation, according to an embodiment. Steerable axle system 300, which is connected to attachment body 210, may comprise a rod 310 and at least two all-wheel drive (AWD) hubs 320. Rod 310 may extend between AWD hubs 320. Each end of rod 310 may be attached to a respective one of AWD hubs 320 by a respective spindle 330. In particular, each spindle 330 may be fixed to the respective AWD hub 320 and joined to rod 310 by a respective kingpin 340, which enables spindle 330 and AWD hub 320 to pivot, relative to rod 310, for steering. For example, the left end of rod 310 may be connected to the left AWD hub 320L via left spindle 330L, which is joined to the left end of rod 310 via left kingpin 340L, and the right end of rod 310 may be connected to the right AWD hub 320R via right spindle 330R, which is joined to the right end of rod 310 via right kingpin 340R.

As used herein, a reference numeral without an appended letter, but with the same numerical component as a reference numeral with an appended letter, will be used to refer to that component generically. For example, the term “AWD hub 320” may refer to either AWD hub 320R or AWD hub 320L, and the term “AWD hubs 320” may refer collectively to AWD hub 320R and AWD hub 320L.

Each ground-engaging member 230 (e.g., wheel) of steerable attachment 200 may be driven by a respective one of AWD hubs 320. For example, a left wheel may be mounted on and driven by left AWD hub 320L, and a right wheel may be mounted on and driven by a right AWD hub 320R. Each AWD hub 320 may comprise a motor that is configured to drive a respective ground-engaging member 230, independently of the other AWD hub 320 and ground-engaging member 230. Thus, for example, left AWD hub 320L may drive the left ground-engaging member 230 at a different speed than the speed at which right AWD hub 320R drives the right ground-engaging member 230. In other words, there may be a speed differential between a pair of ground-engaging members 230.

Steerable axle system 300 may comprise a tie rod 350 connected between at least two steering arms 370. Each steering arm 370 is connected to a respective one of ground-engaging members 230 (e.g., wheels) by virtue of being connected to a respective one of AWD hubs 320. For instance, the left end of tie rod 350 is connected to left AWD hub 320L via left steering arm 370L, and the right end of tie rod 350 is connected to right AWD hub 320R via right steering arm 370R. Tie rod 350 ensures that steering arms 370, and therefore, AWD hubs 320 and their respective ground-engaging members 230, move in unison and in parallel. For example, when left steering arm 370L moves, tie rod 350 fixes the distance between left steering arm 370L and right steering arm 370R, such that right steering arm 370R moves in an identical manner to left steering arm 370L.

Steerable axle system 300 may comprise at least two steering actuators 360. Each steering actuator 360 may comprise a hydraulic system that is connected between a frame of steerable axle system 300 and a respective steering arm 370. The hydraulic system may comprise a cylindrical housing and a piston, connected to a respective steering arm 370, that extends out of and retracts into the cylindrical housing, according to hydraulic pressure applied to the piston. When the piston of steering actuator 360 extends, the piston may push a respective steering arm 370 laterally outward, to thereby steer the connected AWD hub 320 in a first direction. Conversely, when the piston of steering actuator 360 retracts, the piston may pull the end of a respective steering arm 370 laterally inward, to thereby steer the connected AWD hub 320 in a second direction that is opposite the first direction. It should be understood that tie rod 350 fixes the distance between the ends of steering arms 370 that are pushed or pulled, such that steering arms 370 and their respective AWD hubs 320 move in unison and in parallel. Thus, a pair of steering actuators 360 may operate in conjunction to steer ground-engaging members 230 in the first or second direction. For example, right steering actuator 360R may extend and left steering actuator 360L may retract to steer ground-engaging members 230, mounted on AWD hubs 320, to the right. Similarly, right steering actuator 360R may retract and left steering actuator 360L may extend to steer ground-engaging members 230, mounted on AWD hubs 320, to the left. In an alternative embodiment, steering actuators 360 may comprise a different actuating mechanism.

Steerable axle system 300 may comprise a steering sensor 380 that measures the position of steerable axle system 300. In particular, steering sensor 380 may measure the position of one or both of steering actuators 360. Steering sensor 380 may communicate the measured position(s), in real time, via wired or wireless communication, to attachment electronic control module 250.

It should be understood that this is simply one example of steerable axle system 300. There are numerous other architectures for implementing a steerable axle system 300 that is capable of steering and/or rotating one or more ground-engaging members 230. For example, in an alternative embodiment, instead of being steered together, each ground-engaging member 230 may be independently steered. In particular, each ground-engaging member 230 may be connected to a separate electric or hydraulic motor that is configured to steer that ground-engaging member 230, independently of any other ground-engaging member 230. In any embodiment, ground-engaging member(s) 230 may be rotated by independent AWD hubs 320, may be rotated by some other mechanism, or may be castor wheels that are not directly rotated with wheel torque (e.g., but are indirectly rotated by ground-engaging members 130 of work machine 100).

FIG. 4 illustrates a process 400 for steering control, according to an embodiment. Process 400 may be implemented by machine electronic control module 150. While process 400 is illustrated with a certain arrangement and ordering of subprocesses, process 400 may be implemented with fewer, more, or different subprocesses and a different arrangement and/or ordering of subprocesses. In addition, it should be understood that any subprocess, which does not depend on the completion of another subprocess, may be executed before, after, or in parallel with that other independent subprocess, even if the subprocesses are described or illustrated in a particular order.

In subprocess 410, it is determined whether or not work machine 100 has been shutdown. When work machine 100 is shutdown (i.e., “Yes” in subprocess 410), process 400 may end. Otherwise, when work machine 100 remains operating (i.e., “No” in subprocess 410), process 400 may proceed to subprocess 420. It should be understood that process 400 executes in real time as work machine 100 is operated, and therefore, may be executed many times a second.

In subprocess 420, it is determined whether or not work machine 100 is operating in an attachment mode. The attachment mode may be a setting that can be manually activated and deactivated by the operator of work machine 100. For example, machine control(s) 140 may comprise a button, switch, or other input for turning the attachment mode on and off. Alternatively or additionally, the attachment mode may be automatically activated whenever a connection between work machine 100 and steerable attachment 200 is detected. This connection may be automatically detected based on a sensor that detects a physical connection (e.g., via fastening portion 215), the completion of a “handshake” protocol or pairing between machine electronic control module 150 and attachment electronic control module 250, and/or the like. When work machine 100 is operating in the attachment mode (i.e., “Yes” in subprocess 420), process 400 may proceed to subprocess 430. Otherwise, when work machine 100 is not operating in the attachment mode (i.e., “No” in subprocess 420), process 400 may operate in the normal mode in subprocess 470. It should be understood that the normal mode is the standard mode of operation for work machine 100.

In subprocess 430, it is determined whether or not a steering control has been received. Steering control may be received from one or more machine controls 140 in work machine 100 (e.g., being operated by a local operator). For example, the steering control may comprise the position(s) of machine control(s) 140 (e.g., a joystick), which represent turning work machine 100 (e.g., left or right), changing a speed of steering work machine 100 (e.g., via acceleration or deceleration), and/or the like. When a steering control is received (i.e., “Yes” in subprocess 430), process 400 proceeds to subprocess 440. Otherwise, process 400 may return to subprocess 410.

In subprocess 440, one or more steering commands, representing the steering control received in subprocess 430, are sent from machine electronic control module 150 to attachment electronic control module 250. The steering commands may be sent via a wired connection through fastening portion 215. In this case, the same electronic connection between machine electronic control module 150 and steerable attachment 200, which is used to control blade 220, may also be used to communicate the steering commands. Alternatively, the steering commands may be sent via wireless communication from a transmitter of machine electronic control module 150 to a receiver of attachment electronic control module 250.

The steering commands may comprise the steering control or be otherwise derived from the steering control. For example, one or more control parameters, such as the turn radius and/or differential speed (e.g., differential track speed) for ground-engaging members 130 of work machine 100, may be determined based on the steering control that was received in subprocess 410. These values may be determined using a map, stored in a memory of machine electronic control module 150, that maps the position(s) of machine control(s) 140, as represented in the steering control, to values of turn radius and/or differential speed. For example, machine control(s) 140 may comprise a joystick that moves in a forward-aft axis for changing the speed of work machine 100 and a left-right axis for steering work machine 100. In this case, the stored map may comprise a two-dimensional map that specifies the relative speed of the right and left ground-engaging members 130 (e.g., tracks) for all positions of the joystick in the forward-aft and left-right axes. In an alternative embodiment, the turn radius and/or differential speed may be determined in a different manner, or the values of additional or different control parameter(s) may be determined. In any case, the steering commands for steerable attachment 200 may comprise or be derived from the values of these control parameter(s).

In subprocess 450, the steering radius of steerable axle system 300 is received from attachment electronic control module 250. This steering radius represents feedback about the turn radius that steerable axle system 300 is capable of achieving, given the steering commands sent in subprocess 440. The steering radius of steerable axle system 300 may be calculated by attachment electronic control module 250, as discussed elsewhere herein.

In subprocess 460, the steering radius of work machine 100 is matched to the steering radius of steerable axle system 300 that was received in subprocess 450. For instance, the steering control for work machine 100, which was received in subprocess 430, may be changed, constrained, or otherwise manipulated, to prevent the turn radius of work machine 100 from exceeding the capability of steerable attachment 200. In a simple example, the steering radius for work machine 100 may be changed to the steering radius of steerable axle system 300. In a more complicated example, the steering radius of work machine 100 may be mapped or calculated from the steering radius of steerable axle system 300. Notably, subprocesses 430-460 form a closed feedback loop that ensures that the steering capability of work machine 100 does not exceed the steering capability of steerable attachment 200.

FIG. 5 illustrates a process 500 for actuating steerable axle system 300, according to an embodiment. Process 500 may be implemented by attachment electronic control module 250. While process 500 is illustrated with a certain arrangement and ordering of subprocesses, process 500 may be implemented with fewer, more, or different subprocesses and a different arrangement and/or ordering of subprocesses. In addition, it should be understood that any subprocess, which does not depend on the completion of another subprocess, may be executed before, after, or in parallel with that other independent subprocess, even if the subprocesses are described or illustrated in a particular order.

In subprocess 510, it is determined whether or not steerable attachment 200 has been shutdown. When steerable attachment 200 is shutdown (i.e., “Yes” in subprocess 510), process 500 may end. Otherwise, when steerable attachment 200 remains operating (i.e., “No” in subprocess 510), process 500 may proceed to subprocess 520. It should be understood that process 500 executes in real time as steerable attachment 200 is operated, and therefore, may be executed many times a second.

In subprocess 520, it is determined whether or not one or more steering commands have been received. Steering command(s) may be received from machine electronic control module 150, as the reception side of the sending in subprocess 440 of process 400. The steering command(s) may comprise the turn radius and/or differential speed, control commands for the steerable attachment 200 based on the turn radius and/or differential speed, and/or the like. When steering command(s) are received (i.e., “Yes” in subprocess 520), process 500 proceeds to subprocess 530. Otherwise, when no steering command(s) are received (i.e., “No” in subprocess 520), process 500 may return to subprocess 510.

In subprocess 530, steerable axle system 300 is actuated according to the steering command(s) that were received in subprocess 520. In an embodiment in which the steering command(s) include control commands, attachment electronic control module 250 may execute the control commands. In an embodiment in which the steering command(s) include the turn radius, differential speed, and/or other parameter values, attachment electronic control module 250 may determine control commands from these parameter values. For example, attachment electronic control module 250 may derive a turn radius and/or differential speed for ground-engaging members 230 based on the turn radius and/or differential speed for ground-engaging members 130 of work machine 100. In this case, the turn radius and/or differential speed for ground-engaging members 230 may be the same as the turn radius and/or differential speed for ground-engaging members 130 of work machine 100. Alternatively, attachment electronic control module 250 may comprise a map, stored in a memory of attachment electronic control module 250, that maps the turn radius, differential speed, and/or other parameter values, received from machine electronic control module 150, to the turn radius, differential speed, and/or other parameter values for ground-engaging members 230. In any case, the derived parameter values may be used to generate control commands that are then executed by attachment electronic control module 250 to actuate components of steerable axle system 300 to steer and drive ground-engaging members 230. For example, the control commands may actuate steering actuators 360 to steer ground-engaging members 230, and/or actuate AWD hubs 320 to drive ground-engaging members 230.

In subprocess 540, the position of steerable axle system 300 may be measured. In particular, the position of one or both of steering actuators 360 and/or other components of steerable axle system 300 may be measured by steering sensor 380 and communicated from steering sensor 380 to attachment electronic control module 250, via wired or wireless communication.

In subprocess 550, the steering radius of steerable axle system 300 is calculated based on the position(s) measured in subprocess 540. For example, the steering radius of steerable axle system 300 may be mapped or calculated from the measured position(s). This steering radius represents feedback about the turn radius that steerable axle system 300 is capable of achieving.

In subprocess 560, the steering radius, calculated in subprocess 550, is sent from attachment electronic control module 250 to machine electronic control module 150. Subprocess 560 represents the transmission side of the receiving in subprocess 450 of process 400. Notably, subprocesses 520-560 form a closed feedback loop that ensures that the steering of steerable attachment 200 is coordinated with the steering of work machine 100.

FIG. 6 illustrates an example of a controller 600, according to an embodiment. Controller 600 may represent machine electronic control module 150 and/or attachment electronic control module 250.

Controller 600 may comprise one or more processors 610. Processor(s) 610 may comprise a central processing unit (CPU). Additional processors may be provided, such as a graphics processing unit (GPU), an auxiliary processor to manage input/output, an auxiliary processor to perform floating-point mathematical operations, a special-purpose microprocessor having an architecture suitable for fast execution of signal-processing algorithms (e.g., digital-signal processor), a subordinate processor (e.g., back-end processor), an additional microprocessor or controller for dual or multiple processor systems, and/or a coprocessor. Such auxiliary processors may be discrete processors or may be integrated with a main processor 610. Examples of processors which may be used include, without limitation, any of the processors (e.g., Pentium™, Core i7™, Xeon™, etc.) available from Intel Corporation of Santa Clara, California, any of the processors available from Advanced Micro Devices, Incorporated (AMD) of Santa Clara, California, any of the processors (e.g., A series, M series, etc.) available from Apple Inc. of Cupertino, any of the processors (e.g., Exynos™) available from Samsung Electronics Co., Ltd., of Seoul, South Korea, any of the processors available from NXP Semiconductors N.V. of Eindhoven, Netherlands, and/or the like.

Processor 610 may be connected to a communication bus 605. Communication bus 605 may include a data channel for facilitating information transfer between storage and other peripheral components of machine electronic control module 150. Furthermore, communication bus 605 may provide a set of signals used for communication with processor 610, including a data bus, address bus, and/or control bus (not shown). Communication bus 605 may comprise any standard or non-standard bus architecture such as, for example, bus architectures compliant with industry standard architecture (ISA), extended industry standard architecture (EISA), Micro Channel Architecture (MCA), peripheral component interconnect (PCI) local bus, standards promulgated by the Institute of Electrical and Electronics Engineers (IEEE) including IEEE 488 general-purpose interface bus (GPIB), IEEE 696/S-100, and/or the like.

Controller 600 may comprise main memory 615. Main memory 615 provides storage of instructions and data for programs executing on processor 610, such as one or more of the processes or functions discussed herein, such as process 400 or 500. It should be understood that programs stored in the memory and executed by processor 610 may be written and/or compiled according to any suitable language, including without limitation C/C++, Java, JavaScript, Perl, Python, Visual Basic, .NET, and the like. Main memory 615 is typically semiconductor-based memory such as dynamic random access memory (DRAM) and/or static random access memory (SRAM). Other semiconductor-based memory types include, for example, synchronous dynamic random access memory (SDRAM), Rambus dynamic random access memory (RDRAM), ferroelectric random access memory (FRAM), and the like, including read only memory (ROM).

Controller 600 may comprise secondary memory 620. Secondary memory 620 is a non-transitory computer-readable medium having computer-executable code and/or other data (e.g., software implementing any process or function described herein) stored thereon. In this description, the term “computer-readable medium” is used to refer to any non-transitory computer-readable storage media used to provide computer-executable code and/or other data to or within controller 600. The computer software stored on secondary memory 620 is read into main memory 615 for execution by processor 610. Secondary memory 620 may include, for example, semiconductor-based memory, such as programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable read-only memory (EEPROM), and flash memory (block-oriented memory similar to EEPROM).

Controller 600 may comprise an input/output (I/O) interface 635. I/O interface 635 provides an interface between one or more components of controller 600 and one or more input and/or output devices. For example, I/O interface 635 may receive the output of one or more sensors, and/or output control signals to one or more of the components of work machine 100 or steerable attachment 200.

Controller 600 may comprise a communication interface 640. Communication interface 640 allows signals, such as data and software, to be transferred between controller 600 and external devices, networks, or other information sources and/or destinations. For example, computer-executable code and/or data may be transferred to controller 600, over one or more networks, from a network server via communication interface 640. Examples of communication interface 640 include a built-in network adapter, network interface card (NIC), Personal Computer Memory Card International Association (PCMCIA) network card, card bus network adapter, wireless network adapter, Universal Serial Bus (USB) network adapter, modem, a wireless data card, a communications port, an infrared interface, an IEEE 1394 fire-wire, and any other device capable of interfacing controller 600 with a network or another computing device. Communication interface 640 preferably implements industry-promulgated protocol standards, such as Ethernet IEEE 802 standards, Fiber Channel, digital subscriber line (DSL), asynchronous digital subscriber line (ADSL), frame relay, asynchronous transfer mode (ATM), integrated digital services network (ISDN), personal communications services (PCS), transmission control protocol/Internet protocol (TCP/IP), serial line Internet protocol/point to point protocol (SLIP/PPP), and so on, but may also implement customized or non-standard interface protocols as well.

Software transferred via communication interface 640 is generally in the form of electrical communication signals 655. These signals 655 may be provided to communication interface 640 via a communication channel 650 between communication interface 640 and an external system 645. In an embodiment, communication channel 650 may be a wired or wireless network, or any variety of other communication links. Communication channel 650 carries signals 655 and can be implemented using a variety of wired or wireless communication means including wire or cable, fiber optics, conventional phone line, cellular phone link, wireless data communication link, radio frequency (“RF”) link, or infrared link, just to name a few.

Computer-executable code is stored in main memory 615 and/or secondary memory 620. Computer-executable code can also be received from an external system 645 via communication interface 640 and stored in main memory 615 and/or secondary memory 620. Such computer-executable code, when executed by processor(s) 610, enable controller 600 to perform the various processes or functions disclosed herein, such as process 400 or 500.

INDUSTRIAL APPLICABILITY

Traditionally, for certain grading tasks in which a motor grader is not suitable or available, a grader attachment, with caster wheels and a blade or moldboard, may be attached to a work machine 100, such as a skid steer. However, such systems have difficulty operating on irregular terrains, in which lateral forces on blade 220 may cause the caster wheels to lose traction.

Accordingly, a steerable attachment 200 is disclosed with ground-engaging members 230 (e.g., wheels) that can be steered and/or driven via an attachment electronic module 250, which is in communication with machine electronic control module 150 of work machine 100. In particular, machine electronic control module 150 may process steering controls from machine control(s) 140, and convert these into steering commands, which are then sent to attachment electronic control module 250. Attachment electronic control module 250 then steers and/or drives ground-engaging members 230 according to these steering commands, and provides feedback about the steering radius of steerable attachment 200 to machine electronic control module 150. Machine electronic control module 150 uses this feedback to match the steering radius of work machine 100 to the steering radius of steerable attachment 200. In other words, steerable attachment 200 is controlled, in coordination with work machine 100, using the same machine control(s) 140 on work machine 100.

Steerable attachment 200 offers a variety of benefits, including improved steering and traction, higher mechanical advantage, higher machine load, and/or the like. In turn, these benefits improve the functionality of steerable attachment 200. For example, by providing smooth coordinated movement of work machine 100 and steerable attachment 200, work machine 100 is less likely to perturb the ground behind blade 220, resulting in improved grading results. In addition, having motorized ground-engaging members 230 in front of blade 220 helps to counter the forces on blade 220, which are otherwise borne entirely by ground-engaging members 130 of work machine 100.

It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. Aspects described in connection with one embodiment are intended to be able to be used with the other embodiments. Any explanation in connection with one embodiment applies to similar features of the other embodiments, and elements of multiple embodiments can be combined to form other embodiments. The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages.

The preceding detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. The described embodiments are not limited to usage in conjunction with a particular type of industrial context or with a particular type of work machine. Hence, although the present embodiments are, for convenience of explanation, depicted and described as being implemented with construction equipment, it will be appreciated that it can be implemented for various other types of equipment, and in various other environments. Furthermore, there is no intention to be bound by any theory presented in any preceding section. It is also understood that the illustrations may include exaggerated dimensions and graphical representation to better illustrate the referenced items shown, and are not considered limiting unless expressly stated as such.