Stump cutter with automated cutting

Abstract

A stump cutter (100) and method of processing a stump with the stump cutter. A set of setup parameters is recorded with an electronic controller of the stump cutter. An automated multi-axis cutting cycle is initiated on the stump upon receiving an input from an operator control panel (112). During the automated multi-axis cutting cycle, the electronic controller instructs movements of a rotatable cutter wheel (102) with respect to a base portion (104) of the stump cutter to perform multiple horizontal sweeps (S) along a first axis and multiple vertical plunges (P) along a second axis, and the electronic controller further instructing at least one creep movement (C) via a ground drive system (110) of the stump cutter base portion.

Description

STUMP CUTTER WITH AUTOMATED CUTTINGCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to co-pending U.S. Provisional Patent Application No. 63 / 671,930, filed on July 16, 2024, the entire contents of which are incorporated by reference herein.BACKGROUND

[0002] The present invention relates to machines for material reduction of tree stumps by cutting and / or grinding, and more particularly to a control system for cutting with such machines.

[0003] Conventional stump cutters are well known. These machines commonly include a rotating cutter wheel driven by a prime mover (e.g., a gas or diesel engine). The cutter wheel, while rotating, is advanced toward the stump and moved laterally across the face of the stump in a horizontal sweeping movement to reduce the stump material by cutting and / or grinding. The cutter wheel is mounted to one end of a boom which is, in turn, pivotally mounted on a support frame. Hydraulic boom swing cylinders are used to pivot the boom about the pivot point to move the cutter wheel back and forth across the face of the stump to reduce it, layer-by-layer. Advancing the cutter wheel down toward the stump is accomplished by separate hydraulic tilt cylinders that cause the boom to tilt within a vertical plane.

[0004] Commercially available stump cutters have long been available with automated sweeping (e.g., Vermeer Smart Sweep) in which an operator sets a position of the cutter wheel, and then the stump cutter’ s controller automatically controls the speed of sweep horizontally across the stump. Even with an automated sweeping function, the operator of a conventional stump cutter must continuously interact with the machine to set the cutter wheel position between sweeps (e.g., advancing the machine forward and / or adjusting the cutting wheel height in preparation for another sweep pass). This process is repeated until the stump is comminuted to the desired condition. Most often, this includes reducing to stump to a depth below grade. This manual process is prone to inefficiencies and may require a skilled operator. For example, the layer depth could be too shallow for certain sweep movements across the stump, leading to inefficient chipping, taking too much time. Conversely, the layer depth could be too deep for certain sweep movements acrossthe stump, requiring the operator to reposition the cutting wheel, possible machine damage, undesirable operation. Thus, a need exists for a more user-friendly stump cutting system that may reduce the reliance on skilled operator control through automation. Further automation of stump cutters has been stunted by the fact that stump cutters encounter changing conditions as the stump is processed, for example, chips may accumulate around the work site as the comminution process progresses and / or the cutting wheel may cause changes in the terrain when plunging below grade to remove roots.SUMMARY

[0005] In one aspect, the invention provides a stump cutter including a base portion configured for movement along a ground surface by a ground drive system of the stump cutter, and a rotatable cutter wheel movable with respect to the base portion to perform horizontal sweeps along a first axis and vertical plunges along a second axis during reduction of a stump. An operator control panel of the stump cutter is configured, via an electronic controller of the stump cutter, to control creep movements toward and away from the stump by the ground drive system and to control horizontal sweeps and vertical plunges of the cutter wheel in response to manipulation of respective operator controls by the operator. The electronic controller is programmed with an algorithm to conduct an automated multi-axis cutting cycle on the stump upon receiving an input from the operator control panel, the algorithm including instructions to complete the following without subsequent inputs from the operator control panel: conduct multiple horizontal sweeps with respect to the stump, conduct multiple vertical plunges with respect to the stump, and conduct at least one creep movement with respect to the stump.

[0006] In another aspect, the invention provides a method of processing a stump with a stump cutter. A set of setup parameters is recorded with an electronic controller of the stump cutter. An automated multi-axis cutting cycle is initiated on the stump upon receiving an input from an operator control panel. During the automated multi-axis cutting cycle, the electronic controller instructs movements of a rotatable cutter wheel with respect to a base portion of the stump cutter to perform multiple horizontal sweeps along a first axis and multiple vertical plunges along a second axis, and the electronic controller further instructing at least one creep movement via a ground drive system of the stump cutter base portion.

[0007] In yet another aspect, the invention provides a method of processing a stump with a stump cutter. The stump cutter is positioned in front of the stump. A starting height of a rotatable cutter wheel of the stump cutter is determined with an electronic controller of the stump cutter. A final depth for the rotatable cutter wheel of the stump cutter is determined with the electronic controller. An automated multi-axis cutting cycle is initiated on the stump, whereby the electronic controller instructs a sequence of movements of the rotatable cutter wheel to reduce the stump to the final depth. The automated multi-axis cutting cycle, once initiated, completes reduction of the stump to the final depth without requiring any human operator command.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Fig. l is a first perspective view of a stump cutter according to the present disclosure.

[0009] Fig. 2 is a second perspective view of the stump cutter of Fig. 1.

[0010] Fig. 3 is a left side elevation view of the stump cutter of Fig. 1.

[0011] Fig. 4 is a right side elevation view of the stump cutter of Fig. 1.

[0012] Fig. 5 is a top plan view of the stump cutter of Fig. 1.

[0013] Fig. 6 is a front elevation view of the stump cutter of Fig. 1.

[0014] Fig. 7 is a detail perspective view of a connection between a base portion and a boom of the stump cutter of Fig. 1, including sensors configured to measure boom position.

[0015] Fig. 8 is an exemplary display interface for an operator control panel of the stump cutter of Fig. 1, configured to setup operation parameters for an automated cutting cycle.

[0016] Fig. 9 is a process flow diagram for an automated cutting cycle.

[0017] Fig. 10 is a perspective view of a stump, including a coordinate system used in the automated cutting cycle.

[0018] Fig. 11 is a first perspective view of a tow-behind stump cutter coupled to and extended from a truck hitch by a first distance.

[0019] Fig. 12 is a second perspective view of the tow-behind stump cutter coupled to and extended from a truck hitch by a reduced distance compared to the first distance.

[0020] Fig. 13 is a side elevation view of the tow-behind stump cutter having an extendable- retractable trailer hitch tongue fully extended.

[0021] Fig. 14 is a side elevation view of the tow-behind stump cutter having the extendable- retractable trailer hitch tongue fully retracted.DETAILED DESCRIPTION

[0022] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

[0023] Figs. 1-6 illustrate a stump cutter 100 for materially reducing tree stumps by cutting and / or grinding with a rotatable cutter wheel 102. The cutter wheel 102 can have a disc shape, as shown. A plurality of integral or removable cutters are provided on the cutter wheel 102 and configured to engage and reduce the stump during operation. The illustrated cutter wheel 102 is configured for rotation about an axis A that is horizontal. However, other cutter wheel configurations are optional, including discs that rotate about a vertical axis, or drums rather than discs. Separate from the rotation about the axis A, the cutter wheel 102 is movable in multiple directions with respect to a base or main portion 104 of the stump cutter 100. As described in further detail below, the cutter wheel 102 can swing horizontally and can also tilt vertically. The base portion 104 includes a frame, or “mainframe,” 106 that may support a prime mover (not shown) for driving the cutter wheel 102. The base portion 104 further includes a ground drive system 110, including wheels and / or tracks configured to provide motive operation of the stump cutter 100 along a ground surface.

[0024] In order to provide the horizontal swing and vertical tilt capability for the cutter wheel 102, the cutter wheel 102 can be provided on a movable boom 108. The boom 108 has a proximalend coupled to the base portion 104 and a distal end that rotatably supports the cutter wheel 102. As will be appreciated in the art, mechanisms are provided to manipulate the boom 108. These mechanisms can include pivot joints and actuators, such as hydraulic cylinders, the details of which are not examined in more detail, as numerous configurations may be used, including those of various known configurations as well as those of configurations later developed, within the context of the present disclosure. Examples of stump cutter systems and configurations that may be incorporated in part or whole in the stump cutter 100 can be found in U.S. Patent 11,326,655 and U.S. Patent 11,612, 114, the entire contents of both of which are incorporated by reference herein. The stump cutter 100 is configured to provide motion (called “sweep”) of the cutter wheel 102 along a horizontal plane. The boom 108, for example, is movable relative to the base portion 104 in two directions (+ / - sweep “S”, or Left and Right) from a neutral or center position which is shown in the drawings. The stump cutter 100 is configured to provide motion (called “plunge” or “tilt”) of the cutter wheel 102 along a vertical plane. The boom 108, for example, is movable relative to the base portion 104 in two directions (+ / - plunge “P”, or Down and Up). Sweep and plunge movements can each be constrained to a fixed radius arc, in some constructions (i.e., respective fixed pivot axes for each). However, with a different mechanism connecting the boom 108 to the base portion 104, sweep and / or plunge can be configured to move along a variable radius arc or even a straight path. Sweep movements are side-to-side, generally perpendicular to a longitudinal axis LI (Fig. 5) that extends between the proximal and distal ends of the stump cutter 100. Additional horizontal movement of the cutter wheel 102 can be provided along the longitudinal axis LI. These movements, which can be provided by the ground drive system 110 rather than manipulation of the boom 108, can be referred to as + / - creep “C”, or Advance and Retract. Sweep “S”, Plunge “P”, and Creep “C” can define a three-dimensional coordinate system as labeled in Figs. 2 and 10, where S, P, and C represent the three axes.

[0025] The movements of the cutter wheel 102 can be controlled from the controls of an operator interface or control panel 112. In some constructions, the control panel 112 is provided on the stump cutter 100 at a proximal or operator end, which is opposite a distal or cutting end. As will be appreciated, the control panel 112 can include physical controls (e.g., one or more joysticks, etc.) and / or interactive electronic screen(s). Also, it will be appreciated that the control panel 112, or an additional control panel, can be provided on a remote electronic device, which may be a dedicated remote of the stump cutter 100, or a personal handheld electronic device. Inany case, the movements of the cutter wheel 102, among other functions are implemented through a controller 116 in command of the actuators configured to move the cutter wheel 102. Movement of the cutter wheel 102 with respect to a stump may be accomplished in three-dimensional space by separate inputs from an operator to the control panel 112. In particular, the control panel 112 can include operator controls individually operable to control + / - creep (which moves the entire stump cutter 100), + / - sweep (which moves the boom 108 horizontally), and + / - plunge (which moves the boom 108 vertically). As described further below, the control panel 112 can also enable the operator to input a command to initiate an automated multi-axis cutting cycle in which combinations of two or more of sweep, plunge, and creep are conducted without interstitial operator command.

[0026] The controller 116 may include one or more electronic processors and one or more memory devices. The controller 116 may be communicably connected to one or more sensors or other inputs, such as described herein. The electronic processor may be implemented as a programmable microprocessor, an application specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGA), a group of processing components, or with other suitable electronic processing components. The memory device (for example, a non-transitory, computer- readable medium) includes one or more devices (for example, RAM, ROM, flash memory, hard disk storage, etc.) for storing data and / or computer code for completing the or facilitating the various processes, methods, layers, and / or modules described herein. The memory device may include database components, object code components, script components, or other types of code and information for supporting the various activities and information structure described in the present application. According to one example, the memory device is communicably connected to the electronic processor and may include computer code for executing one or more processes described herein. The controller 116 may further include an input-output (“I / O”) module. The I / O module may be configured to interface directly with one or more devices, such as a power supply, sensors, displays, etc. In one embodiment, the I / O module may utilize general purpose I / O (GPIO) ports, analog inputs / outputs, digital inputs / outputs, and the like.

[0027] In order to track and control the position of the cutter wheel 102 in relation to a stump, a plurality of sensors are provided on the stump cutter 100, each connected to the controller 116 to provide a signal thereto. As shown in Fig. 7, one or more boom sensors 124, 126 are provided.The first boom sensor 124 is operable to detect the horizontal swing or sweep position of the boom 108 in relation to the base portion 104. The first boom sensor 124 can measure boom angle about a first boom pivot axis (sweep axis). The controller 116 can receive the signal from the first boom sensor 124 and determine a horizontal position of the cutter wheel 102 (e.g., by factoring in an offset distance between the cutter wheel 102 and the sweep axis). In some constructions, the first boom sensor 124 is a string potentiometer. However, the first boom sensor 124 can be implemented with other suitable sensor topologies, including but not limited to Hall-Effect Rotary Position Sensor, Position Sensing Hydraulic Cylinder, Hydraulic Cylinder Pressure, Position Feedback Electric Actuator, Rotary Encoder, Machine Vision (Camera, LiDAR, 4D Radar), and / or Linear Distance Sensing. The second boom sensor 126 is operable to detect the vertical tilt or plunge position of the boom 108 in relation to the base portion 104. The second boom sensor 126 can measure boom angle about a second boom pivot axis (tilt axis). The controller 116 can receive the signal from the second boom sensor 126 and determine a vertical position of the cutter wheel 102 (e.g., by factoring in an offset distance between the cutter wheel 102 and the tilt axis). In some constructions, the second boom sensor 126 is a Hall-Effect Rotary Position Sensor. However, the second boom sensor 126 can be implemented with other suitable sensor topologies, including but not limited to Inertial Measurement Unit (IMU), Position Sensing Hydraulic Actuator, Hydraulic Cylinder Pressure, Position Feedback Electric Actuator, Rotary Encoder, Machine Vision (Camera, LiDAR, 4D Radar), and / or Linear Distance Sensing.

[0028] Additionally, because the position of the cutter wheel 102 in relation to a stump is also affected by the orientation of the base 104 (e.g., as it moves over uneven ground), the stump cutter 100 includes at least one sensor 128 configured to measure orientation of the base portion 104. In some constructions, the sensor 128 is an Inertial Measurement Unit (IMU). However, the sensor 128 can be implemented with other suitable sensor topologies, including but not limited to GPS or machine vision (camera, LiDAR, 4D radar). The sensor 128 can detect and report to the controller 116 a pitch angle or change in pitch angle. Pitch angle can refer to deviation of the longitudinal axis LI from horizontal, or in other words, height difference between the fore / aft ends of the stump cutter 100. The controller 116 can then modify (offset) a boom tilt command (plunge depth stroke as measured between the boom 108 and the base portion 104), especially during an automated cutting cycle, that controls an amount of plunge of the cutter wheel 102 with respect to the stump.

[0029] With reference to Fig. 10, a stump to be reduced by the stump cutter 100 will have a unique size and shape. Thus, before enacting an automated cutting cycle, the controller 116 of the stump cutter 100 obtains a set of input parameters. The set of input parameters include, but are not limited to, characteristics of the particular stump in front of the stump cutter 100. For example, the total plunge stroke includes not only the above ground height of the stump, but also the desired depth below ground that should be reduced. This parameter may vary stump-to-stump, and may be configurable by the operator by input to the controller 116. In addition to total plunge stroke, the number of layers L to accomplish the total plunge stroke must be determined. The number of layers L equals the total plunge stroke divided by the depth of each layer L. The appropriate depth of each layer L may depend on the type of wood in the stump, the condition and configuration of the cutters on the cutter wheel 102, etc. The stump of Fig. 10 is shown schematically in a configuration where the near side (left) with respect to the stump cutter (not shown) has been swept according to a number of layers L (e.g., four) before completing the sweeps according to these layers L on the far side (right). Advancing the stump cutter wheel 102 longitudinally from the near side to the far side of the stump is accomplished by creeping forward with the ground drive system 110. A plurality of creep steps may be required to traverse the entire length of the stump, depending on the overall length of the stump and the size of the cutter wheel 102. In practice, the sequencing or choreography for reducing the stump can be performed according to several different options. In some sequences, all of the depth layers L are completed on the stump at a first longitudinal creep position before moving forward to a subsequent longitudinal position or creep step to repeat cutting through all the depth layers L. In other sequences, the stump is reduced in complete layers L such that material is reduced from the top of the stump before plunging to a further depth, and then the stump cutter repeats the process for another complete layer. Aspects of these sequences can also be combined into a hybrid sequence in which multiple (but less than the total number of) layers are completed before advancing through the sequence of longitudinal positions or creep steps. One or more cutting sequences can be pre-programmed to the controller 116. Sequences, or parameters thereof, may be variable according to operator input.

[0030] Fig. 8 illustrates one example of a display interface 136 for the operator control panel 112 of the stump cutter 100, which enables inputting stump parameters for an automated cutting cycle. In this example, the display interface 136 has input sections for stump dimensions (e.g., plan view). Length input can correspond to the longitudinal span of the stump, along thelongitudinal axis LI or creep axis C. Width input can correspond to the span of the stump perpendicular to the length, which corresponds to the sweep axis S. The display interface can also include an input section for selection of the stump shape (e.g., plan view). In the illustrated example, the display interface provides for an operator selection among a plurality of geometric options, such as Square, Circle, and Oval inputs. Although stump height or depth (i.e., the vertical measure of the stump above ground) may also be input via the display interface 136 in some constructions, the automated cutting cycle can in other constructions be continued to run the cutter wheel 102 below grade until the operator determines that the stump is adequately reduced and inputs a command to stop the automated cutting cycle. In some constructions, the stump cutter 100 can include one or more sensors to corroborate the operator’s stump inputs. The starting and stopping positions for Sweep S, Plunge P, and Creep C can be set by the operator and input to the controller 116, determined by the controller 116 based at least on stump parameters, or a combination thereof. The above are examples of a set of setup parameters recorded by the electronic controller for the automated cutting cycle on a particular stump. The electronic controller 116 either receives an input or calculates: a total plunge depth, a plunge depth for each of a plurality of layers L, a sweep stroke for the multiple horizontal sweeps between a left sweep limit and a right sweep limit, a total creep length, and a creep length for each of the multiple creep movements.

[0031] In some constructions, the operator teaches (or demonstrates to) the controller 1 16 the sweep span desired for a given stump by sweeping the boom 108 between the desired starting and stopping positions, which are flagged to or by the controller 116 (e.g., by the operator making an input to the control panel 112 when at the particular position, or the controller 116 recognizing the maximum extent of the various movements). This can be done prior to cutting the stump, or done during the initial stages of cutting the stump. The same applies for the total forward creep between starting and ending creep positions, unless the length of the stump precludes it. The same applies also for the total plunge depth between starting and ending plunge positions, with the exception that below ground plunge depth cannot be performed prior to cutting, and must either be provided as a numerical input by the operator before cutting or recording via flagging during cutting once the operator reaches the final depth on the initial portion of the stump. Thus, the setup parameters can be populated and recorded to the controller 116 by preliminary data entry, by flagging current positions, or combinations thereof.

[0032] As mentioned above, one or more sensors of the stump cutter 100 can detect stump size and / or shape parameters to corroborate operator inputs. However, in some constructions, the sensor(s) alone are used by the stump cutter 100 to determine one or more (e.g., all) of the stump parameters used for setup of the controller 116 to enable the automated cutting cycle (without quantitative operator inputs to the display interface 136). The sensor(s) constitute a vision system of the stump cutter 100. The vision system can include one or more cameras 140 (FIG. 1) with respective digital image sensors to obtain and record one or more digital images of the stump. As illustrated in FIG. 1, the vision system can include multiple cameras 140 positioned offset from the longitudinal axis LI. The cameras 140 can be mounted near the top of the stump cutter 100. In other constructions, the cameras 140 are mounted lower (e.g., in the lower half) on the stump cutter 100. The vision system can further include an image processing module (e.g., of the controller 116) configured to receive the digital image(s) and determine the size and shape of the stump. The image processing module, based on the data from the vision system sensor(s) may create stump measurements. The stump measurements can optionally be in the form of a 3-D model of the stump, or may be used for the electronic controller 116 to create a 3-D model of the stump. Once the stump measurements are determined, the controller 116 can determine and set the appropriate setup parameters that provide for complete coverage of the stump by the cutter wheel 102 during the automated cutting cycle. In other constructions, the vision system is not limited to cameras with digital image sensors. In lieu of, or in addition to, one or more cameras, the vision system can include a 3-D scanner such as a LiDAR scanner 144 (FIG. 1). As illustrated in FIG. 1, the LiDAR scanner 144 can be positioned at or near the longitudinal axis LI. The LiDAR scanner 144 can be on a forward-facing housing or frame portion, above the cutter wheel 102. In other constructions, the LiDAR scanner 144 is positioned elsewhere on the stump cutter 100.

[0033] As described in detail below with respect to the exemplary algorithm or program of Fig. 9, the controller 116, once equipped with adequate setup parameters, is programmed to conduct multiple sweeps across the stump at different depths and / or different forward creep positions, without interstitial operator command. Prior to the process shown in Fig. 9, the operator may drive the stump cutter 100 to a position in which the stump is directly in front of the stump cutter 100. For example, the operator positions the longitudinal axis LI of the stump cutter 100 near a center line of the stump. The operator positions the base portion 104 and the boom 108such that the cutter wheel 102 is in a raised position above the stump. Initially, the automated stump cutter program is disabled as represented at step SI. The operator engages the cutter wheel (step S2) to begin a cutting process. Before commencing the automated cutting cycle at step S4 (e.g., pressing an automation start button), the controller 116 may go through a series of checks and data collection at step S3. For example, the stump cutter 100 may automatically prompt the operator to input automation startup parameters, or the operator may select via the control panel 112 that they wish to utilize the automated cutting cycle rather than manually setting the positions for each stump cutting layer. At step S3, start position data can be collected. The data collected and stored at step S3 may include data defining the starting position of the machine 100, and more particularly a starting position of the cutter wheel 102, such as information from the sensor 128 (e.g., machine pitch), the boom angle sensor 124 (boom sweep position), boom height (rotary sensor, tilt) sensor 126, and the ground drive position (such as ground drive encoder data), all of which contribute to the position of the cutter wheel 102 in space. The data related to the start position is stored by the controller 116 and referenced in the logic detailed below to determine the relative position of the base portion 104 and the boom 108. Step S3 can also include the controller 116 obtaining physical parameters of the stump and / or starting / stopping points for the movements of the cutter wheel 102. As already noted, these can be learned by the controller 116 from sensors on the stump cutter 100, inputs from the operator, or a combination thereof. The checks at step S3 may include the shutdown events listed above to verify the automated stump cutting process can be performed. When the necessary checks have been completed and fall within an acceptable range at step S3, the controller 116 may indicate to the operator (e.g., through a signal, status message on a remote control, a light, or audible sound) that the automated stump cutting process can begin. At step S4, the operator inputs a “start” or “go” command. The controller 116 may then commence the multi-axis automated stump cutting cycle. It is also noted that some of the above setup parameters and / or pre-checks of step S3 can be conducted by the controller 116 in response to the user’s “start” or “go” command for the automated process at step S4. As such, the controller 116 may respond to the “start” or “go” command with further prompts for input, or an error message indicating why the automated process cannot commence.

[0034] At step S3, or at least upon the automation start button being pressed at step S4, the controller 116 determines the automated strategy for cutting the stump, including the various movements of the cutter wheel 102 (start and stop points for the back and forth sweeps of the boom108, the number and depth of plunge layers L, and the number and distance of advancing steps of the ground drive 110) and also the particular sequence thereof. A counter of the controller 116 keeps a plunge count, which is initially set to zero for the beginning of the cycle at step S5. As noted later, the number of plunge layers L for the total plunge count, or “plunge limit,” is set to 5 in this non-limiting example. The action of the automated cutting cycle begins by sweeping the boom left at step S6 (starting from where the operator has positioned the boom 108, the start position). Upon completion of the sweep left, as measured by the boom swing sensor 124 where the boom angle is greater than the left sweep parameter (step S7), the boom 108 is actuated to plunge downward at step S8 and the plunge count increases by one. The controller 116 plunges the boom 108 down until the controller 116 determines the boom height is less than or equal to the prior height, less the preset plunge distance (for cutting the first layer L) at step S9. The controller 116 uses output data from the boom tilt sensor 126. The controller 116 then commands the boom 108 to sweep right at step S10 until a sweep parameter has been reached (as measured the boom swing sensor 124), such as where the boom angle is greater than the right sweep parameter at Step Si l. Upon completing the right sweep, the controller 116 determines if the plunge count is less than the total plunge limit (e.g., 5) at step S12. If yes at step S12, the controller 116 plunges the boom 108 the preset amount (for cutting the second layer L) and increases the plunge count by one at step S13. The controller 116 lowers the boom 108 until it is determined, e.g., from the boom tilt sensor 126, that the boom height is less than or equal to the prior height, less the plunge distance at step S14. The controller 116 then proceeds to sweep the boom left at step S6. It should be noted that relative terms such as “greater than,” “less than,” etc. are used with reference to the actual angle, actual height, etc. for the ease of understanding, although it will be understood that sensors and controller logic may be scaled or mapped arbitrarily in practice (e.g., + / - voltage values).

[0035] As illustrated at steps S6 - S14, the process of sweeping in a first direction, plunging, sweeping back in a second direction, and plunging again is repeated until the plunge count is greater than the predetermined limit (e.g., 5). It should be noted that this example shows a series of 5 plunges, before the stump cutter 100 creeps to the next position (the logic proceeds toward step SI 8). The quantity of 5 plunges is non-limiting example, and an automated cutting cycle can include a different number of plunges (0, 1, 2, 3, 4, or more than 5) before the stump cutter 100 creeps to the next position. Other examples may utilize the total plunge distance (instead of plunge count) before creeping (for example, step S12 may be replaced with “Is the total plunge distancegreater than X” where X is a set distance such as 2 inches). Yet other embodiments may continue plunging until the final depth has been reached before the stump cutter 100 creeps forward.

[0036] Continuing with the flow diagram of Fig. 9, once the plunge count reaches the limit at step S12 (e g., plunge count < 5 = NO), the total tracking (creep) distance is compared to the preentered stump length to determine if the cutting wheel 102 is at the end of the stump (step S 15). If not at the end of the stump, the boom 108 is raised at step S16 and the plunge count is reset to zero. The boom raise command is stopped when the boom 108 is raised to a height greater than or equal to the starting height at step SI 7. The controller 116 then commands the stump cutter 100 to creep forward at step S18 a preset amount (one forward creep step), which, as shown at step SI 9, the new position of the stump cutter 100 will be a forward location that is greater than or equal to the sum of the prior position plus the preset creep amount. The creep (or any ground drive travel in the logic) may be measured by an encoder on the ground drive system, such as motors and / or shafts. Alternatives for determining the travel distance may include cameras mounted on the stump cutter 100 to sense surroundings and operating the ground drive system 110 for a preset amount of time, other options include GPS positioning and ultra-wideband localization. Machine position data relative to the ground drive, such as starting location, creep amount, and total creep amount, may be stored and utilized by the controller 116.

[0037] At step S20, the boom height is checked to see if it has been affected by repositioning the stump cutter 100 along uneven terrain (e.g., of the natural terrain and / or collection of chips from cutting the stump) encountered during the creep forward of step SI 8. The controller 116 can check if the boom height is greater than or equal to the start height. If yes at step S20, the boom height is either correct or may be too high with respect to the stump. The controller 116 lowers the boom 108 at step S21 until the boom height is less than or equal to the start height at step S22. Returning to step S20, if the boom height is less than the start height (i.e., NOT greater than or equal to the start height), the boom is too low, and the controller 116 raises the boom 108 at step S23 until the boom height is greater than or equal to the start height at step S24. As described further below, this routine accomplishes a pitch adjustment that can alter the plunge depth stroke between the boom 108 and the base portion 104 in order to achieve consistent height settings and plunge depths relative to the stump, after creeping the stump cutter 100 to a new position on the ground adjacent the stump. Despite completing a prescribed amount of upward boom tiltcorresponding to the starting height (e.g., confirmed by the boom tilt sensor 126), the actual boom height, and thereby the cutting height of the cutter wheel 102, is affected by the pitch angle of the stump cutter 100. This is accounted for within the controller 116, which determines actual height of the cutter wheel 102 relative to the stump using the pitch angle (p) from the pitch sensor 128 and the boom angle (a) from the boom tilt sensor 126, and inputting the values into the function presented below (see Fig. 4 for labeled variables):

[0038] (%) = * cos(p) + c2* sin(p + a) — c3

[0039] ci: Distance from Ground to Boom Mount Pin

[0040] C2: Distance from Cutter Wheel Center to Boom Mount Pin

[0041] cs: Cutter Wheel Radius

[0042] The output of the function can be used to determine relative changes in the height of the boom 108, such as a determination of Yes or No at step S20 (and other boxes where the relative boom height is considered). For example, in the logic below, data from the pitch sensor 128 and the boom tilt sensor 126 may be collected, stored, and utilized in the equation when the stump cutter 100 is in the start position (data from step S5) to determine the starting height of the boom 108. As mentioned above, the machine creeps forward (step S18) to a stop position (step S19.5) or rearward (step S25) to a stop position (step S27) (the stump cutter 100 is now in a new position relative to the start position) the data from the pitch sensor 128 and the boom tilt sensor 126 may be collected, stored, and utilized in the equation to make the determinations at step S20 or step S28, respectively. The output of the function from the start position can be compared to the output of function when the stump cutter 100 is in another stopped position (the new position) to determine if the relative difference in boom height between the start position and other stopped position. This allows the boom height to be (corrected) adjusted in response to any changes in machine position due to the terrain encountered during forward or rearward travel. The controller 116 can then adjust the boom height (raise or lower) accordingly to the desired height, which in the logic (steps S20, S25, and / or S22), is the equal to the starting height. Terrain changes may be caused by the ground surface which the stump cutter 100 rests on and / or changes in the groundsurface due the stump cutting process, such as accumulation of chips caused during chipping, and / or removal of soil due to cutting below grade.

[0043] In some configurations the base portion 104 has a pitch sensor 128, and the boom 108 also has a pitch sensor (e.g., another IMU). In this configuration, the same equation would be used but the boom pitch would be known (not derived from the boom tilt sensor 126).

[0044] In some configurations machine location tracking may be added, such that the tracking / creeping distance is accounted for, allowing the height to change (increase or decrease) while tracking over a mound.

[0045] When the boom 108 is at the corrected start height (from step S22 or S24), the sweeping and plunging cycle (step S6 - S14) repeats until the predetermined plunge count is met, and the forward tracking (step SI 8) and height correction (S19-S24) cycle repeats until the controller 116 determines that the cutting wheel 102 has traversed the entire stump (Yes at step S15, the sum of the creeping distance exceeds stump length). The controller 116 then commands the ground drive system 110 to track / creep in reverse (step S25) to the start position. From step S25, the controller 116 determines whether the machine position is less than or equal to the start position (step S26) (as determined by tracking time / or distance described above), where the machine stops (step S27) and the controller 116 compares the most recent plunge depth to the final depth (step S28). If the final depth has not been reached (No at step S28), the controller 116 lowers the boom 108 to the next cutting depth (plunge)(steps S29, S30), increases the plunge count (step S31). Correction of the boom height may be included between step S27 and step S6. The controller 116 repeats the series of sweeps, plunges, creeping (steps S6 - S24) until the final depth has been reached (Yes at step S28). When the final depth and final distance has been reached the automated logic ends (step S32) and the controller 116 stops the cutting wheel 102, may alert the operator, and / or may raise the cutter wheel 102.

[0046] In some constructions, cutting of a stump commences with the operator commanding the start of the automated cutting cycle, and the stump cutter 100 completely reduces the entire stump to the total depth (e g., subterranean) without any further inputs (e.g., adjustments or other commands) from the human operator. As such, the stump cutter 100 is configured for completeautomatic reduction of a stump, and the operator simply supervises the actions of the stump cutter 100 during reduction of the stump by the stump cutter 100.

[0047] The automated stump cutting sequence may be shutdown (stopped) during any of the following events or combination of events:• Operator Presence Not Detected - remote or on machine.• Cutter Wheel Stopped / Driveline Protection System / Cutter Wheel Stalling (Pressure)• Machine Faults (Sensor Offline, Engine Fault, Hydraulic Fault)• Not Cutting / No Acceleration / Vibration Detected During Sweep• Cutter Wheel Acceleration Detects Metal / Concrete / etc.• Cutter Wheel Vibration Detects Metal / Concrete / etc.• Human Presence Detection near the cutter wheel• Machine Rollover• Machine Moves Unintentionally (e.g., machine rocks during chipping, or boom contacts something during chipping that causes the frame to move (because boom is stopped / stuck)).

[0048] The stump cutter 100 is provided as an integrated or single-purpose work machine, as opposed to a detachable work implement for a tractor or other device. In other words, the boom 108 with the cutter wheel 102 and the prime mover are on-board components with respect to the mainframe 106. However, aspects of the disclosure may also be provided in “mounted” stump cutters configured for attachment to a mini skid-steer or general purpose tractor, for example where the mainframe is mounted to a three-point linkage of a tractor. Aspects of the disclosure may also be incorporated into stump cutters of other configurations, such as the tow-behind stump cutter described in further detail below.

[0049] As opposed to self-propelled machines that are generally trailered to a work site, unloaded, and driven under their own power to the stump site, the tow-behind stump cutter 200 ofFIGS. 11-14 has a proximal end (opposite the distal end with the cutter wheel 202) that is configured for attachment to a trailer hitch (e.g., on a truck 205). In particular, the stump cutter 200 includes a trailer hitch tongue 210. The trailer hitch tongue 210 is configured to remain connected to the trailer hitch of the truck 205, both during transport to the stump site and during operation of the stump cutter 200 to reduce the stump with the cutter wheel 202. However, creep movements during stump cutting are enabled by the stump cutter 200, without requiring movement of the truck 205 that tows the stump cutter 200. Although reference is made to the preceding description of the stump cutter 100 for the majority of features of the tow-behind stump cutter 200, it is briefly noted that the tow-behind stump cutter 200 includes a base or main portion 204 on which the boom 208 is movably supported. The control panel 212 is located on a lateral side of the tow-behind stump cutter 200, outside the sweep range of the boom 208, although other configurations for the control panel 212 including remote control devices are optional. The illustrated control panel 212 can be part of a stowable control station. In particular, the control station may pivot from the illustrated position into a stowed (non-operating) position that reduces the lateral width of the stump cutter 200 for transport.

[0050] In some constructions, the trailer hitch tongue 210 of the tow-behind stump cutter 200 is an extendable-retractable (telescopic) tongue to provide movement of the stump cutter 200 along the longitudinal axis LI or creep axis C relative to the stump. The extendable-retractable tongue 210 and a rolling assembly 215 (e g., a set of wheels on an unpowered axle) constitute the ground drive system of the tow-behind stump cutter 200. The extendable-retractable tongue 210 can include a hydraulic actuator 220 (e.g., double-acting hydraulic cylinder) extendable to creep forward and back (thereby the truck towing the stump cutter does not need to be moved for each creep). In some constructions, the hydraulic actuator 220 has a stroke (between the maximum extended position of FIG. 13 and the maximum retracted position of FIG. 14) of about 60 inches, corresponding to the same amount of available creep movement. The position and amount of movement of the hydraulic actuator 220 for creeping can be determined by a position sensing system, or in other words, an encoder on the ground drive system. In the illustrated construction, the position sensing system includes an encoder 225 on the extendable-retractable tongue 210. The encoder 225 or position sensing system can be carried out by a variety of sensors, including but not limited to linear distance sensors (LVDT), alternatively, a machine vision system (camera, LiDAR, 4D Radar) could determine the position and creep distance. Otherwise, the tow-behindstump cutter is similar to the self-propelled stump cutter 100 of the preceding description and figures including, for example, the sensors, the controller, and the method of operation - of which a separate description is not provided to avoid redundancy.

[0051] Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of one or more independent aspects of the invention as described.

Claims

CLAIMSWhat is claimed is:

1. A stump cutter comprising: a base portion configured for movement along a ground surface by a ground drive system of the stump cutter; a rotatable cutter wheel movable with respect to the base portion to perform horizontal sweeps along a first axis and vertical plunges along a second axis during reduction of a stump; and an operator control panel configured, via an electronic controller of the stump cutter, to control creep movements toward and away from the stump by the ground drive system and to control horizontal sweeps and vertical plunges of the cutter wheel in response to manipulation of respective operator controls by the operator, wherein the electronic controller is programmed with an algorithm to conduct an automated multi-axis cutting cycle on the stump upon receiving an input from the operator control panel, the algorithm including instructions to complete the following without subsequent inputs from the operator control panel: conduct multiple horizontal sweeps with respect to the stump, conduct multiple vertical plunges with respect to the stump, and conduct at least one creep movement with respect to the stump.

2. The stump cutter of claim 1, wherein the electronic controller is configured to record a set of setup parameters for the automated multi-axis cutting cycle, including a total plunge depth and a plunge depth for each of a plurality of layers.

3. The stump cutter of claim 2, wherein the set of setup parameters for the automated multiaxis cutting cycle further includes a sweep stroke for the multiple horizontal sweeps, between a left sweep limit and a right sweep limit.

4. The stump cutter of claim 3, wherein the set of setup parameters for the automated multiaxis cutting cycle further includes a total creep length and a creep length for each of the multiple creep movements.

5. The stump cutter of claim 2, further comprising a vision system including one or more sensors operable to detect the stump and produce stump measurements, wherein the electronic controller is in communication with the vision system to receive the stump measurements and, based on the stump measurements, determine the set of setup parameters.

6. The stump cutter of claim 1, further comprising a pitch sensor in communication with the electronic controller and operable to measure pitch angle of the stump cutter, wherein the algorithm for the automated multi-axis cutting cycle includes the electronic controller being configured to adjust a height of the rotatable cutter wheel after each of the at least one creep movement by an amount corresponding to the pitch angle measured by the pitch sensor.

7. The stump cutter of claim 6, wherein the pitch sensor includes an Inertial Measurement Unit (IMU) configured to measure pitch angle of the base portion.

8. The stump cutter of claim 6, wherein the pitch sensor includes an Inertial Measurement Unit (IMU) configured to measure pitch angle of a boom that supports the rotatable cutter wheel with respect to the base portion.

9. The stump cutter of claim 1, further comprising a boom that supports the rotatable cutter wheel with respect to the base portion, wherein the electronic controller is configured to track a position of the rotatable cutter wheel with respect to the base portion by a boom sweep sensor and a boom tilt sensor.

10. The stump cutter of claim 9, wherein the boom sweep sensor is a string potentiometer, and the boom tilt sensor is a Hall-Effect rotary position sensor.

11. The stump cutter of claim 1, wherein the operator control panel is configured to accept a stump shape as a setup parameter for the automated multi-axis cutting cycle.

12. The stump cutter of claim 1, wherein the operator control panel is configured to accept a stump length and a stump width as a set of setup parameters for the automated multi-axis cutting cycle.

13. The stump cutter of claim 1, wherein the stump cutter is a self-propelled stump cutter configured to drive to a site of the stump via powered wheels and / or tracks of the ground drive system.

14. The stump cutter of claim 1, wherein the stump cutter is a tow-behind stump cutter, wherein the ground drive system includes an extendable-retractable trailer hitch tongue and a set of wheels on an unpowered axle.

15. A method of processing a stump with a stump cutter, the method comprising: recording a set of setup parameters with an electronic controller of the stump cutter; initiating an automated multi-axis cutting cycle on the stump upon receiving an input from an operator control panel; and during the automated multi-axis cutting cycle, the electronic controller instructing movements of a rotatable cutter wheel with respect to a base portion of the stump cutter to perform multiple horizontal sweeps along a first axis and multiple vertical plunges along a second axis, and the electronic controller further instructing at least one creep movement via a ground drive system of the stump cutter base portion.

15. The method of claim 15, wherein a pitch sensor measures pitch angle of the stump cutter and sends a signal representative thereof to the electronic controller, the electronic controller adjusting a height of the rotatable cutter wheel after the at least one creep movement by an amount corresponding to the pitch angle measured by the pitch sensor.

16. The method of claim 16, wherein the at least one creep movement is a plurality of creep movements, and after each of the plurality of creep movements, the electronic controller reacquires the pitch angle from the pitch sensor and re-adjusts a height of the rotatable cutter wheel by an amount corresponding to the pitch angle measured by the pitch sensor.

17. The method of claim 15, wherein recording the set of setup parameters includes populating a total plunge depth for the automated multi-axis cutting cycle.

18. The method of claim 15, wherein recording the set of setup parameters includes populating a total sweep stroke, either by data entry to the electronic controller, or by moving the rotatable cutter wheel to a first sweep position that is flagged to the electronic controller as a left sweeplimit, and moving the rotatable cutter wheel to a second sweep position that is flagged as a right sweep limit.

19. The method of claim 15, wherein recording the set of setup parameters includes recording inputs of one or both of: a set of stump dimensions and a stump shape.

20. The method of claim 15, wherein the set of setup parameters are determined by the electronic controller in response to receiving output from a vision system of the stump cutter that detects the stump with one or more sensors and produces stump measurements.

21. A method of processing a stump with a stump cutter, the method comprising: positioning the stump cutter in front of the stump; determining a starting height of a rotatable cutter wheel of the stump cutter with an electronic controller of the stump cutter; determining a final depth for the rotatable cutter wheel of the stump cutter with the electronic controller; and initiating an automated multi-axis cutting cycle on the stump, whereby the electronic controller instructs a sequence of movements of the rotatable cutter wheel to reduce the stump to the final depth, wherein the automated multi-axis cutting cycle, once initiated, completes reduction of the stump to the final depth without requiring any human operator command.

22. The method of claim 20, wherein during the automated multi-axis cutting cycle, the electronic controller instructs movements of the rotatable cutter wheel with respect to a base portion of the stump cutter to perform multiple horizontal sweeps along a first axis and multiple vertical plunges along a second axis, and the electronic controller further instructing at least one creep movement via a ground drive system of the stump cutter base portion.

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