Collision Avoidance Control Method and System

Abstract
A control method and system for avoiding collisions between components of a machine includes a controller that receives position signals from sensors associated with movable components of the machine. The controller determines the positional coordinate representations of the components within a coordinate system based upon the position signals and the outer dimensions of the respective components. If any of the components are within preset collision slowdown or shutdown zones within the coordinate system, then the speed of those components is restricted or the components are shutdown, respectively, in the direction of collision.
Description
TECHNICAL FIELD

This disclosure relates generally to a system for removing material and, more particularly, to a system and method for dynamically controlling the system to avoid collisions between the components of the system.


BACKGROUND

Mobile machines may be configured for underground operation to perform tunneling or underground mining. Such machines may have a low profile design and include an undercarriage with continuous tracks or similar propulsion devices to transport the machine about the underground worksite. Stabilizers may be utilized to press downwardly to resist unwanted pitching and rolling motions of the machine during milling operations.


To perform a cutting or milling operation, a rotary cutter head is disposed on a tool support and positioning assembly supported by the undercarriage. The tool support and positioning assembly can be configured to move the cutter head in multiple directions to make passes or sweeps with respect to the milling wall thereby removing successive layers of material from the milling wall.


U.S. Publication No. 2015/0204190 describes a mobile mining machine having a movable machine base frame, a rotatable tool drum, and excavating tools.


The foregoing background discussion is intended solely to aid the reader. It is not intended to limit the innovations described herein, nor to limit or expand the prior art discussed. Thus, the foregoing discussion should not be taken to indicate that any particular element of a prior system is unsuitable for use with the innovations described herein, nor is it intended to indicate that any element is essential in implementing the innovations described herein. The implementations and application of the innovations described herein are defined by the appended claims.


SUMMARY

In one aspect there is provided a machine for removal of material from a surface. The machine has an undercarriage having a front end and a rear end, supported on a plurality of propulsive drive mechanisms that may be used to position the machine proximate to the surface. The machine also includes a cutter head disposed on a tool support and positioning assembly, which is supported on the undercarriage. The tool support and positioning assembly is moveable relative to the undercarriage. At least one support position sensor is associated with the tool support and positioning assembly, and adapted to dynamically determine the position of the tool support and positioning assembly. A gathering head is coupled to the front end of the undercarriage. The machine also includes a controller configured to receive a tool support position signal from the at least one support position sensor, determine respective positional coordinate representations of the gathering head, the tool support and positioning assembly, and the cutter head within a coordinate system. The controller determines if any of the gathering head, the tool support and positioning assembly, and the cutter head are within a preset collision slowdown zone within the coordinate system based on the respective positional coordinate representations, and if any of the gathering head, the tool support and positioning assembly, and the cutter head are within a preset collision shutdown zone within the coordinate system based on the respective positional coordinate representations. If any of the gathering head, the tool support and positioning assembly, and the cutter head is within said preset collision slowdown zone, the controller restricts the speed of the gathering head, the tool support and positioning assembly, and the cutter head in a direction of collision within said preset collision slowdown zone to a reduced speed within said preset collision slowdown zone. If any of the gathering head, the tool support and positioning assembly, and the cutter head is within said preset collision shutdown zone, then the controller stops movement of the gathering head, the tool support and positioning assembly and the cutter head in the direction of collision within the preset collision shutdown zone. If none of the gathering head, the tool support and positioning assembly, and the cutter head is within at least one of the preset collision slowdown zone and the preset collision shutdown zone, then the controller permits full speed movement of the tool support and positioning assembly.


In another aspect, there is provided a method of avoiding collisions between components of machine having a gathering head, and a cutter head disposed on a movable tool support and positioning assembly. The tool support and positioning assembly is moveable relative to the gathering head. The cutter head is moveable relative to the gathering head at a speed. The method includes receiving at least one tool support position signal from the at least one support position sensor, and determining respective positional coordinate representations of the gathering head, the tool support and positioning assembly, and the cutter head within a coordinate system. The method also includes determining at least one of the following: if any of the gathering head, the tool support and positioning assembly, and the cutter head are within a preset collision slowdown zone within the coordinate system based on the respective positional coordinate representations; and if any of the gathering head, the tool support and positioning assembly, and the cutter head are within a preset collision shutdown zone within the coordinate system based on the respective positional coordinate representations. If any of the gathering head, the tool support and positioning assembly, and the cutter head is within said preset collision slowdown zone, then the method restricts the speed of the gathering head, the tool support and positioning assembly, and the cutter head in a direction of collision within said preset collision slowdown zone to a reduced speed within said preset collision slowdown zone. If any of the gathering head, the tool support and positioning assembly, and the cutter head is within said preset collision shutdown zone, then the method stops movement of the tool support and positioning assembly in the direction of collision within the preset collision shutdown zone. If none of the gathering head, the tool support and positioning assembly, and the cutter head is within at least one of the preset collision slowdown zone and the preset collision shutdown zone, then the method permits full speed movement of the tool support and positioning assembly.


In still another aspect, there is provided a machine for underground milling of a wall. The machine includes an undercarriage having a front end and a rear end. The machine also includes a cutter head and a tool support and positioning assembly, which is supported on the undercarriage. The machine also includes a gathering head, and a controller. The controller is configured to determine coordinates of the tool support and positioning assembly, and the cutter head within a coordinate system, and coordinates of the gathering head within the system. The controller is also configured to determine at least one of the following: if any of the gathering head, the tool support and positioning assembly, and the cutter head are within a preset collision slowdown zone within the system; and if any of the gathering head, the tool support and positioning assembly, and the cutter head are within a preset collision shutdown zone within the system. If any of the gathering head, the tool support and positioning assembly, and the cutter head is within said preset collision slowdown zone, the controller then restricts the speed of the gathering head, the tool support and positioning assembly, and the cutter head within said preset collision slowdown zone to a reduced speed within said preset collision slowdown zone. If any of the gathering head, the tool support and positioning assembly, and the cutter head is within said preset collision shutdown zone, then the controller stops movement of the tool support and positioning assembly is in the direction of collision within the preset collision shutdown zone. If none of the gathering head, the tool support and positioning assembly, and the cutter head is within at least one of the preset collision slowdown zone and the preset collision shutdown zone, then the controller permits full speed movement of the tool support and positioning assembly.





BRIEF DESCRIPTION OF THE DRAWINGS


FIG. 1 is a front isometric view of an embodiment of a machine configured for removing material, with certain parts removed, incorporating the principles disclosed herein.



FIG. 2 is a side elevational view of an embodiment of a machine in an underground worksite with the cutter head oriented with respect to a surface and supported on a tool support and positioning assembly including extendable and retractable boom infeed extension.



FIG. 3 is a fragmentary bottom isometric view of the machine of FIG. 1;



FIG. 4 is a schematic view of an exemplary hydraulic actuator and sensor;



FIG. 5 is a diagrammatic view of an exemplary side elevational view of a coordinate system representing components of a machine;



FIG. 6 is a diagrammatic view of an exemplary isometric view of the coordinate system of FIG. 5 representing components of a machine;



FIG. 7 is a flowchart of a process of avoiding collision in the operation of a machine; and



FIG. 8 is a flowchart representing an exemplary arrangement for tracking the positions and outer dimensions of relatively movable components in the process illustrated in FIG. 7.





DETAILED DESCRIPTION

Now referring to the drawings, wherein like reference numbers refer to like elements, there is illustrated in each of FIGS. 1 and 2 a mobile or movable machine 100 for removing material from a surface and configured for operations such as tunneling, underground mining, or the like. In some embodiments, the machine 100 may be a milling machine and the surface may be a milling surface or a milling wall, such as milling wall 108 (shown in FIG. 2). The machine 100 may be relatively large, on the order of several meters in length, and may be intended to remove material in quantities sufficient to create underground workspaces that are meters high and wide. To propel or transport the machine 100 about the underground worksite, the machine 100 can include an undercarriage 102 configured with a plurality of continuous tracks 104 disposed on opposite sides of the machine 100 that can propel the machine 100 in the forward or reverse directions as well as turn the machine 100 side-to-side. As shown in FIG. 2, the continuous tracks 104 translate as a closed loop or belt with respect to the tunnel floor 106 to position the machine 100 with respect to a milling surface or milling wall 108 from which material such as rock is to be removed. While the illustrated embodiment includes two continuous tracks 104, other embodiments may include any suitable number of continuous tracks 104 or may utilize different propulsive drive mechanisms.


To remove material (e.g., cut or mill material) from the milling wall 108, the machine 100 includes a cutter head 110 having a plurality of cutting tools 112 disposed about its radial periphery. The cutter head 110 can include a gear box 114 upon which a drum structure 115 is rotatably mounted about a cutter head axis 116, thereby revolving the cutting tools 112 with respect to the milling wall 108. The cutting tools 112 can be supported in corresponding sockets disposed in the drum structure 115 and, in an embodiment, can be made to forcibly rotate or spin about their respective axes within the drum structure 115 for increased cutting action. To impact and dislodge material from the milling wall 108, a plurality of bits 118 can be disposed about the exterior surface of the cutting tools 112. The bits 118 can be made of tungsten carbide, polysynthetic diamond, or a similar material having good hardness characteristics. As the bits 118 wear down, the cutting tools 112 may be removed from the cutter head 110 and replaced.


To support cutter head 110 and to move it in passes or sweeps with respect to the milling wall 108, the cutter head 110 can be supported on a tool support and positioning assembly 120 that is configured to move or pivot in multiple directions or about various axes. In particular, the tool support and positioning assembly 120 suspends the cutter head 110 proximately over the front end 122 of the machine 100 and includes various systems and structures that are disposed over the undercarriage 102 extending toward the rear end 123 of the machine 100. The tool support and positioning assembly 120 includes an elongated boom infeed extension 124 that can be generally supported over the continuous tracks 104 on rails or the like to enable translation with respect to the undercarriage 102. For example, to feed the cutter head 110 into the milling wall 108 or to retract the cutter head 110 from the milling wall 108, the tool support and positioning assembly 120 includes a boom infeed extension 124 that is slidably disposed on the undercarriage 102 to translate in the forward and rearward directions along a longitudinal boom axis, the direction of which is indicated by the double-headed arrow 126. To cause the boom infeed extension 124 to translate along the forward and rearward directions along the boom axis, as indicated by double-headed arrow 126, the boom infeed extension 124 can be operatively associated with one or more boom actuators 128. The boom actuators 128 may be of any appropriate design, for example, an electric motor or a hydraulic boom actuator 128, such as illustrated in FIG. 2. The boom actuator 128 may be located on the rear end 123 of the machine 100 and arranged to slide the boom infeed extension 124 toward and from the front end 122 to feed and retract the cutter head 110. In an embodiment, the travel distance of the boom infeed extension 124 between a fully extended position toward the front end 122 of the machine 100 and a fully retracted position toward the rear end 123 may be about a meter or more.


To cause the cutter head 110 to sweep in a side-to-side motion, the tool support and positioning assembly 120 can include a swing platform 130 such as a pivot table or the like supported on the boom infeed extension 124 that pivots the cutter head 110 with respect to the undercarriage 102. Actuation of the swing platform 130 moves the cutter head 110 horizontally in an arc about the vertically orientated swing axis 132. To actuate the swing platform 130, the swing platform 130 can be operatively associated with one or more swing actuators 134. The swing actuators 134 may be of any appropriate design, for example, an electric motor or a hydraulic swing actuator 134, such as illustrated in FIG. 2, connected to either side of the swing platform 130 and to the boom infeed extension 124. It will be appreciated that extension of one hydraulic swing actuator 134 and retraction of the other will rotate the swing platform 130 though a horizontal plane about the swing axis 132.


To vertically raise and lower the cutter head 110 with respect to the tunnel floor 106 and milling wall 108, the tool support and positioning assembly 120 can include a cantilevered lift arm 140 disposed along the swing platform 130. The cantilevered lift arm 140 can move the cutter head 110 along the laterally extending tilt axis 142, which is parallel with the cutter head axis 116, as illustrated in FIGS. 1 and 2. In particular, the cantilevered lift arm 140 extends over the front end 122 of the machine 100 and has a hinge or pivot joint 144 that articulates the forward part of the cantilevered lift arm 140 in an up-and-down motion. To actuate the cantilevered lift arm 140, one or more lift actuators 146 can be operatively arranged on the cantilevered lift arm 140 to articulate the pivot joint 144. The lift actuators 146 may be of any appropriate design, for example, an electric motor or a hydraulic lift actuator 146, such as illustrated in FIG. 2. In a further possible embodiment, to twist or roll the cutter head 110, the distal end of the cantilevered lift arm 140 can be configured as a wrist joint or rollover joint 148 that rolls or rotates the cutter head axis 116 with respect to the rest of the machine 100.


Because the cutter head 110 is disposed over the front end 122 of the machine 100, the material it removes from the milling wall 108 will gather in front of the machine 100 and can hinder further milling operations. To remove the gathered material, the front end 122 of the machine 100 can be equipped with a gathering head 150 that extends across the width of the machine 100 below the cutter head 110 proximate to the tunnel floor 106. The gathering head 150 can be configured to collect the material from the tunnel floor 106.


The gathering head 150 may include a loading table 151 having opposing, adjustable gathering wings 152. In this way, the width of the gathering head 150 may be adjusted to the width of the tunnel floor 106 by adjustment of the gathering wings 152. Those of skill in the art will appreciate that movement of the gathering wings 152 may be provided by one or more wing actuators. The wing actuators may be of any appropriate design, for example, an electric motor, a hydraulic wing actuator, or manual operation. Where manual operation occurs, the wing actuators may include mating components and locking structures that allow the gathering wings 152 to slide relative to the loading table 151.


In at least one embodiment, the gathering head 150 may be adjusted relative to the undercarriage 102 by one or more gathering head actuators 153. The gathering head actuators 153 may be of any appropriate design, such as, for example, the hydraulic gathering head actuators 153 shown in FIG. 2. As shown in FIG. 2, in order to pivotably adjust the gathering head 150 relative to the undercarriage 102, the loading table 151 may be pivotably mounted to undercarriage 102, for example, at a pivot joint 155. In this way, actuation of the gathering head actuators 153 would pivot the loading table 151 about pivot joint 155. Those of skill in the art will appreciate that the gathering head 150 may also be adjusted in a longitudinal direction or may be pivoted relative to the undercarriage 102 in an embodiment. For example, the gathering head actuators 153 may extend to pivot the loading table 151 in a clockwise direction in the side view illustrated in the embodiment of FIG. 2, or retract to pivot the loading table 151 in a counter-clockwise direction.


To remove the material collected by the gathering head 150, a conveyor 154 in the form of a translating belt is disposed through the machine 100 that passes the material from the front end 122 through to the rear end 123 of the machine 100. The conveyor entrance 156 can be an opening centrally disposed in the skirt of the gathering head 150 with the conveyor 154 extending lengthwise through the machine 100 above the undercarriage 102 to the conveyor exit 158 located at the rear end 123 of the machine 100.


To direct the material to the conveyor 154, the gathering head 150 can include gathering arms 159 that sweep across the surface of the gathering head 150 toward the conveyor entrance 156. The gathering arms 159 may be of any appropriate design. For example, the gathering arms 159 may be one or more pivotably mounted arms, such as those shown in FIG. 2, or one or more rotatably mounted multi-arm gathering stars, such as those illustrated in FIG. 1.


Referring to FIG. 2, during the cutting or milling operation, to remove material discharged at the conveyor exit 158, a secondary conveyor system 160, separate from the machine 100 can be positioned proximate to the rear end 123 of the machine 100 that extends to the entrance of the underground worksite. Accordingly, the machine 100 and the secondary conveyor system 160 are configured to continuously remove material from the worksite. In an alternative embodiment, instead of a separate conveyor system 160, carts may be used to carry the material away.


To power the machine 100 and movement of the cutter head 110 on the tool support and positioning assembly 120, the machine 100 can be equipped with one or more electric motors 170 that advantageously utilize electricity and avoid generating exhaust fumes in the underground worksite. A remote power source, such as a generator, can provide three-phase electrical power to the electric motors 170 via cables. In the embodiments in which the continuous tracks 104 and hydraulic actuators of the tool support and positioning assembly 120 are hydraulically operated, a hydraulic system 172 including a hydraulic pump and a hydraulic fluid reservoir can be operatively associated with the electric motors 170 to generate fluid pressure for operation.


To further facilitate the milling operation, the machine 100 can be equipped with one or more extendable and retractable ground-engaging devices. In at least one embodiment, the ground-engaging devices are operatively associated with the hydraulic system 172. For example, to stabilize the machine 100 during a cutting or milling operation, the machine 100 can be equipped with a plurality of stabilizers 180 that can be disposed along the underside of the undercarriage 102 (see FIGS. 2 and 3). For example, left and right stabilizers 180 may be located at the front end 122 of the undercarriage 102, as shown in FIG. 3, and one or more rear stabilizers 180 may be provided as the rear end 123, as shown in FIG. 2.


The stabilizers 180 can include a stabilizer actuator 182 that can extend and retract a ground-engaging portion 184 with respect to the tunnel floor 106. The stabilizer actuators 182 may be of any appropriate design, for example, an electric motor or a hydraulic stabilizer actuator 182, such as illustrated in FIGS. 2 and 3.


The ground-engaging portion 184 may be of any appropriate design, such as, for example, a ground-engaging pad, as illustrated in FIG. 2, or a ground-engaging wheel, as illustrated in FIG. 3, or a combination of such designs. During a milling operation, the stabilizer actuator 182 extends the ground-engaging portion 184 to engage the tunnel floor 106, brace, and support the machine 100 with respect to vibrations and oscillations generated by cutting into the milling wall 108. To enable the machine 100 to move about the underground worksite, the stabilizer actuator 182 retracts the ground-engaging portion 184 generally adjacent to the undercarriage 102.


The hydraulic actuators that serve as the boom actuators 128, swing actuators 134, lift actuators 146, gathering head actuators 153, wing actuator, and stabilizer actuators 182 can be configured as double acting hydraulic cylinders with telescoping pistons that extend and retract from the cylinder body. However, in other embodiments of the machine 100, one or more of the actuators may be other hydraulic devices or electric motors or the like.


To regulate and control operation of the machine 100, an electronic control system 190 can be included as shown in FIG. 1. The electronic control system 190 may include a controller 191 and can have any suitable computer architecture and can be in electronic communication with the various components and systems on the machine 100 to send and receive electronic signals in digital or analog form that enable the electronic control system 190 to monitor and regulate the operations and functions of the machine 100. The electronic control system 190 may execute and process functions, steps, routines, control maps, data tables, charts, and the like saved in and executable from computer readable and writable memory or another electronically accessible storage medium to control the machine. To perform these functions and operations, the electronic control system 190 can be configured as a microprocessor, an application specific integrated circuit (“ASIC”), or other appropriate circuitry and may have memory or other data storage capabilities. The memory can include any suitable type of electronic memory devices such as random access memory (“RAM”), read only memory (“ROM”), dynamic random access memory (“DRAM”), flash memory and the like. Although in the schematic representation of FIG. 1, the electronic control system 190 is represented single, discrete unit, in other embodiments, the electronic control system 190 and its functions may be distributed among a plurality of distinct and separate components.


In an embodiment, the machine 100 may be remotely operated through the electronic control system 190. As illustrated in FIG. 1, a remote control 192 can be in communication with the electronic control system 190 to send and receive operation signals that direct operation of the machine 100. Accordingly, an operator can stand away from the machine 100 while controlling its operations via the remote control 192. Communication between the electronic control system 190 and the remote control 192 may be wireless, i.e., via radio signals or other electromagnetic technology, or may be conducted through control cables. The remote control 192 can include various dials, switches, and controls to interface with the electronic control system 190 on the machine. For example, to selectively operate the continuous tracks 104 to position or reposition the machine 100 with respect to the milling wall 108, the remote control 192 can include a multi-directional joystick. Similarly, a second multi-directional joystick can be used to maneuver and position the cutter head 110 through use of the tool support and positioning assembly 120. It should be appreciated that in other embodiments, the machine 100 may include an onboard operator station having the various controls necessary to operate the machine 100.


In at least one embodiment, the electronic control system 190 and the remote control 192 may be configured for either or both automated or automatic control and operator or manual control of the machine 100. If automatic control is selected, the electronic control system 190 may be directed to operate using any one of a plurality of predetermined milling sets to maneuver the cutter head 110 with respect to the milling wall 108. The predetermined milling sets can be embodied as software instructions that can be stored in and executable by the electronic control system 190 to direct the tool support and positioning assembly 120 to maneuver the cutter head 110. If the manual control is selected, the remote operator may utilize the remote control 192 to control operations of the machine 100, including the tool support and positioning assembly 120.


As indicated, the cutter head 110 and the tool support and positioning assembly 120 can be maneuvered through a plurality of distinct positions to remove material from the milling wall 108 during a cutting or milling operation. During operation, it may be possible for movable components of the machine 100 to collide with one another or with stationary components of the machine 100, that is, relatively moveable components may collide with one another during operation. For example, it is possible for the tool support and positioning assembly 120 and/or the cutter head 110 to collide with the gathering head 150, or for the front stabilizers 180 to collide with the loading table 151.


In order to avoid such collisions, there is provided a system and method for avoiding collisions. More specifically, the respective positions of at least two of the tool support and positioning assembly 120, the cutter head 110, the gathering head 150, and the front stabilizers 180 are tracked within a coordinate system. For the purposes of this disclosure, these may be referenced as “tracked components.” For the purposes of the disclosure, the term “positional coordinate representation” will refer to coordinates identifying the position of the tracked component within the coordinate system. For the purposes of this disclosure, the term “direction of collision” will refer to the directional component of relative movement between the tracked component that would result in a collision between the tracked components should movement be permitted to continue. When relative movement of these tracked components enters a warning zone or slowdown zone, the speed of movement of the tracked components within the slowdown zone is restricted in the direction of collision. When relative movement of these tracked components enters a watch zone or shutdown zone, movement of the tracked components is shutdown in the direction of collision.


The coordinate system may be of any appropriate type in which the positions of the tracked components are trackable based upon positional data and dimensions of tracked components. One such coordinate system is a Cartesian coordinate system. For the purposes of the disclosure, the term “Cartesian coordinate” will be either of two coordinates that locate a point on a plane and measure its distance from either of two intersecting straight-line axes along a line parallel to the other axis; and/or any of three coordinates that locate a point in space and measure its distance from any of three intersecting coordinate planes measured parallel to that one of three straight-line axes that is the intersection of the other two planes.


In order to track the positions of the tracked components, at least one position sensor may be provided to provide a signal indicative of an associated moveable component. The sensor may be of any appropriate design at any appropriate location. By way of example, one or more linear or rotary sensors may be provided at appropriate locations to provide a signal indicative of an associated moveable component.


For example, the tool support and positioning assembly 120 may be provided with at least one sensor disposed at any appropriate location(s). In the illustrated embodiments, at least one of each of the boom actuators 128, the swing actuators 134, and the lift actuators 146 are provided with a boom sensor 200, a swing sensor 202, and a lift sensor 204, respectively. While such sensors are illustrated with regard to each of the actuators, it will be appreciated that all or less than all actuators may be provided with such sensors. Further, one or both of opposing actuators may be provided with such sensors. For example, only one or both of the swing actuators 134 may be provided with such swing sensors 202.


In the illustrated embodiments, at least one of the gathering head actuators 153 is provided with a gathering head sensor 210. Inasmuch as the gathering head actuators 153 may independently move the position of the loading table 151 of the gathering head 150, however, in at least one embodiment, that gathering head actuators 153 on opposite sides of the undercarriage 102 both include gathering head sensors 210.


One or both of the stabilizer actuators 182 likewise may be provided with a stabilizer sensor 212. In a manner similar to the gathering head actuators 153, the stabilizer actuators 182 independently control the position of the respective front left and right stabilizers 180. Accordingly, in at least one embodiment, respective stabilizer sensors 212 are associated with the stabilizer actuators 182 of the front left and right stabilizers 180.


The sensors 200, 202, 204, 210, 212 associated with the boom actuators 128, the swing actuators 134, the lift actuators 146, gathering head actuators 153, and the stabilizer actuators 182, if provided, may be of any appropriate design. For example, one or more of the sensors 200, 202, 204, 210, 212 associated with hydraulic cylinders may be linear position sensors, such as the sensor illustrated. In the embodiment illustrated in FIG. 4, the sensor 200, 202, 204, 210, 212 monitors the position of a magnet 214 movably positioned over the shaft 216 within the cylinder 218. In this way, a signal provided by a sensor 200, 202, 204, 210, 212 is indicative of the respective distance that the associated cylinder has extended or retracted. Those of skill in the art will appreciate that one or more of the sensors 200, 202, 204, 210, 212 may be of an alternate design.


In order to more accurately track the position of the cutter head 110, the rollover joint 148 between the tool support and positioning assembly 120 and the cutter head 110 may likewise be provided with a sensor 220. The sensor 220 may be of any appropriate design. For example, a rotary sensor may be provided. In at least one embodiment, the sensor 220 is a rotary encoder that is positioned to sense the degree to which the rollover joint 148 has rotated. Should the cutter head 110 be provided with one or more cooling spray bars or heads, sensors may likewise be provided in connection with such cooling spray heads.


In this way, a signal indicative of the position of the associated tracked component is conveyed from each of the sensors 200, 202, 204, 210, 212, 220 to the electronic control system 190. From these signals in conjunction with the geometry of the respective movable tracked component, that is, the outward-most extent of each respective movable component, the controller of the electronic control system 190 may determine the positional coordinate representation of the respective movable tracked component within a coordinate system and establish preset collision slowdown zones and preset collision shutdown zones. Cartesian coordinate representations of certain movable tracked components are illustrated, for example, in the Cartesian coordinate system representations of FIGS. 5 and 6. The controller of the electronic control system 190 is adapted to controls movement of the movable tracked components within one or more preset collision slowdown zones by reducing speeds in the direction of collision, and is adapted to discontinue movement of a movable tracked component within one or more preset collision shutdown zones. For example, a first preset collision slowdown zone and first preset collision shutdown zone may be established between the tool support and positioning assembly 120/cutter head 110 and the gathering head 150, and a second preset collision slowdown zone and second preset collision shutdown zone may be established between the stabilizers 180 and the gathering head 150.


Referring to FIGS. 5 and 6, the tool support and positioning assembly 120 is represented by the Cartesian coordinate line(s) 232 connecting the small circles. The position of the tool support and positioning assembly 120 may be determined based upon the geometry of the same and the signals of the boom sensor(s) 200, swing sensor(s) 202, and lift sensor(s) 204. In this embodiment, the cutter head 110 is represented as a Cartesian coordinate sphere 234, which encapsulates all wrist positions of the rollover joint 148. In this way, the controller will not allow the tool support and positioning assembly 120 to place the cutter head 110 in a position in which the rotation of the rollover joint 148 would cause a collision of the cutter head 110 with the gathering head 150.


Referring to FIGS. 5 and 6, the Cartesian coordinate representation of the gathering head 150 are represented by the Cartesian coordinate line or lines 240 between the squares. The position of the gathering head 150 is determined based upon the geometry of the gathering head 150 as well as the positions of signal(s) of the gathering head sensor(s) 210.


In determining the preset collision slowdown zones and preset collision shutdown zones relative to the geometry of the respective movable tracked components, certain assumptions may be made. For example, the geometry of the gathering head 150 may take into account all locations of the opposing gathering wings 152, and the geometry of the gathering head 150 may take into account cut material that may build up on the surface of the loading table 151. Accordingly, the outermost dimension along the upper surface of the gathering head 150 may include a protective area (e.g., a protective envelope or mesh 242, such illustrated in FIG. 5). The Cartesian coordinate representations of the protective envelope 242 are represented by the dotted triangular structure in FIG. 5, and the dotted lines identified in FIG. 6.


The positions of the front left and right stabilizers 180 relative to the undersurface of the gathering head 150 are determined by the dimensions of the respective stabilizers 180, as well as the signal from the stabilizer sensor(s) 212. In the embodiment illustrated in FIGS. 5 and 6, the Cartesian coordinate representations front left and right stabilizers 180 are represented by the stars 244, while an undersurface of the gathering head 150 is represented by the dotted lines 246.


Using this information, the controller of the electronic control system 190 utilize the coordinate system to establish one or more preset collision slowdown zones and one or more preset collision shutdown zones. For example, a preset collision slowdown zone and a preset collision shutdown zone may be established between Cartesian coordinate line(s) 232, 234 of the tool support and positioning assembly 120 and the cutter head 110, and the Cartesian coordinate representations 240 of the gathering head 150 and protective envelope 242 to such that the movement of the tool support and positioning assembly 120 and cutter head 110 will be limited to avoid collision with the gathering head 150. Similarly, the gathering head 150 cannot be moved into a collision condition with the tool support and positioning assembly 120.


Likewise, a preset collision slowdown zone and a preset collision shutdown zone may be established between the Cartesian coordinate representations of the underside of the gathering head 150 and front left and right stabilizers 180. In this way, the front left and right stabilizer 180 cannot be raised into a collision condition with the underside of the gathering head 150.


In at least one embodiment, the anti-collision control routine is always active during both manual and automatic operation. The preset collision slowdown zone(s) and preset collision shutdown zone(s) are predetermined based upon the relative positions of the encroaching tracked components and their dimensions, rather than dynamic zones, encroaching tracked components generally reaching the preset collision slowdown zone prior to reaching the preset collision shutdown zone. By way of example only, a preset collision shutdown zone may be within 50 millimeter of collision, while a preset collision slowdown zone may be within 100 millimeters of collision, but outside of the predetermined shutdown zone. Within the preset collision shutdown zone, movement of the encroaching tracked components may be shutdown entirely in the direction of collision.


Conversely, within the predetermined slowdown zone, movement of the encroaching tracked components maybe restricted in the direction of collision. In this regard, such restriction may be by way of a percentage of a maximum velocity limit of the tracked component, for example, 10%. Alternatively, such restriction may be by way of a set velocity, for example, x mm/sec.


Moreover, operation within the predetermined slowdown zone may vary based upon the mode of operation. That is, in an embodiment, velocity of the encroaching tracked components may be limited only in the direction of collision when the machine 100 is being operated manually. That is, the encroaching tracked components would be permitted to operate at full speed in all directions other than the direction of collision within the collision slowdown zone when in manual operation. Conversely, when the machine is being operated automatically, the velocity of the tool support and positioning assembly 120 may be limited proportionally in all directions. In this way, the restriction of the velocity of the encroaching tracked components in the direction of collision will not affect the programmed cutting path of the cutter head 110.


It will further be appreciated that the predetermined slowdown zone and predetermined shutdown zone may be particular to the encroaching tracked components. For example, the predetermined slowdown zone for the gathering head 150 and the tool support and positioning assembly 120/cutter head 110 may be larger than the predetermined slowdown zone for the gathering head 150 and the stabilizers 180.


According to another feature of some embodiments, if functionality is impeded by the limitations imposed on the range of movement, the electronic control system 190 may generate an alert. Such an alert may be provided to the operator by way of the remote control 192, for example.


The following is an example of the limit map for the limit of a collision distance between the underside of the gathering head 150 and the stabilizer(s) 180. According to the following limit map, when the gathering head 150 and stabilizer(s) 180 are 60 mm or further apart, the respective velocities of the tracked components are not limited. Conversely, when the gathering head 150 and stabilizer(s) 180 are 50 mm apart, that is, the at the preset collision slowdown zone, the respective velocities of the tracked components are limited to 10% of their respective maximum speeds in the direction of collision. Further, when the gathering head 150 and stabilizer(s) 180 are 40 mm apart or less, that is, when the encroaching tracked components reach the preset collision shutdown zone, movement of the encroaching tracked components is shutdown entirely in the direction of collision in order to avoid collision.


















Preset collision
Preset collision




Collision
Shutdown Zone
Slowdown Zone



















mm from
0
40
50
60


collision






% velocity limit
0
0
10
100









INDUSTRIAL APPLICABILITY

Turning now to the process diagram illustrated in FIG. 7, the positions of the relatively movable tracked components are tracked and the outer dimensions of the relatively movable tracked components are determined (Step 302). From this information, the respective positional coordinate representations of the tracked components are determined within a coordinate system (Step 304), such as the Cartesian coordinate system representations shown in FIGS. 5 and 6.


The information provided at Step 302 for determination of the positional coordinate representations at Step 304 is illustrated in greater detail in FIG. 8. As explained above, the positional coordinate representations 240 of the gathering head 150 along with the positional coordinate representations of a protective envelope 242 are determined based upon the dimensions of the loading table 151 and gathering wings 152, and position of the gathering head actuators 153 based upon signals from the gathering head sensor(s) 210, and the position of the wing actuators 224, if provided. The positional coordinate representations 244 of the front left and right stabilizers 180 are provided based upon the dimensions of the same and the positions of the left and right stabilizer actuators 182 based upon signals from the left and right stabilizer sensors 212, respectively. The positional coordinate representations 232, 234 of the tool support and positioning assembly 120 and the cutter head 110 are determined based upon the dimensions of the same, and the positions of the boom infeed extension 124, cantilevered lift arm 140, the rollover joint 148, cutter gear box 114, and cooling spray head 226, based upon the positions of the boom actuator(s) 128, the swing actuator(s) 134, the lift actuator(s) 146, and the rollover joint 148 based upon signal from the associated boom sensor 200, swing sensor 202, lift sensor 204, and rollover joint sensor or rotary encoder 220.


Returning to FIG. 7, at Decision Box 306, it is determined if any of the tracked components are within a preset collision slowdown zone. If no tracked components are within the preset collision slowdown zone, the method returns Step 302 for continued dynamic monitoring of the tracked components.


Conversely, if it is determined at Decision Box 306 that at least some portion of the tracked components are within the preset collision slowdown zone, then it is determined whether the machine 100 is in manual or automatic operation (Step 308). If the machine is in automatic operation, then the speed of all of the tracked components is restricted (Step 310), as, for example, by a percentage. It will thus be appreciated that if the tool support and positioning assembly 120 is moving the cutter head 110 along a predetermined cutting path, that cut will not be altered, just reduced in speed.


In automatic operation, at Decision Box 312, it is then determined if any of the tracked components are within a preset collision shutdown zone. If not, while operating in automatic operation, the method returns to Step 310, continuing to restrict the speed of all movable tracked components. If any of the tracked components are within the preset collision shutdown zone, however, all movement is stopped with regard to the components within the preset collision shutdown zone (Step 314). Thus, for example, if a portion of the tool support and positioning assembly 120 is disposed within the preset collision shutdown zone, all movement of the tool support and positioning assembly 120 will stop.


Conversely, if it is determined at Step 308 that the machine is in manual operation, then the speed of the encroaching tracked components is restricted within the preset collision slowdown zone in the direction of collision only (Step 316). Full speed of the tracked components not within the predetermined slowdown zone is permitted, and full speed of the encroaching tracked components is permitted in all directions other than the direction of collision (Step 318). The position of the tracked components not within the predetermined slowdown zone continues to be monitored, however, as the method returns to Decision Box 306.


While operating in manual operation, at Decision Box 320, it is determined if any of the tracked components are within a preset collision shutdown zone. If not, then the method returns to Step 316, continuing to restrict the speed of encroaching tracked components within the preset collision slowdown zone in the direction of collision. If, however, any portion of the tracked components is within the predetermined shutdown zone, movement of the encroaching tracked components within the predetermined shutdown zone is shutdown entirely in the direction of collision (Step 322).


While Decision Boxes 312 and 320 are illustrated as separate steps, it will be appreciated that, they may be a single step. If it is determined that no portion of the tracked components is within the preset collision shutdown zone, the method would return to Step 310 if operating in automatic operation, or to Step 316 if operating in manual operation. Conversely, if it is determined that any portion of the tracked components is within the preset collision shutdown zone, and the machine 100 is in manual operation, then movement of the encroaching tracked components is stopped within the preset collision slowdown zone in the direction of collision. If, however, any portion of the tracked components is within the predetermined shutdown zone and the machine is operating in automatic operation, all movement is stopped with regard to the components within the preset collision shutdown zone (Step 314).


While the method as illustrated in FIG. 7 shows the step of determining whether any tracked components are disposed within the preset collision shutdown zone (Decision Boxes 312, 320) subsequent to the step of determining whether any tracked components are disposed within the preset collision slowdown zone (Decision Box 306), those of skill in the art will appreciate that the step may occur simultaneously. That is, there may be a continuous monitoring of whether any tracked components are within the either the preset collision slowdown zone (Decision Box 306) or within the collision shutdown zone (Decision Boxes 312, 320). Alternatively, if it is determined that any portion of the tracked components is disposed within one or the other of the preset collision slowdown zone or the preset collision shutdown zone, then the method may proceed to either restrict the speed of the encroaching tracked components (Steps 310, 316), or stop movement of the encroaching tracked components (Steps 314, 322).


It will be appreciated that the indication of whether a tracked component is in the preset collision slowdown zone or within the preset collision shutdown zones necessarily includes whether any portion of the tracked component is within the respective zone. For the purposes of this disclosure and the appended claims, an identification or indication of one or more tracked components being disposed within a preset collision slowdown zone or a preset collision shutdown zone does not require that the entirety of the subject tracked component be disposed within the preset collision slowdown zone or the preset collision shutdown zone. Rather, any portion of the tracked component being disposed within the preset collision slowdown zone or the preset collision shutdown zone means that the subject tracked component is within the preset collision slowdown zone or the preset collision shutdown zone.


Further, while certain of the method steps have been described as occurring if the machine 100 is under automatic operation, it will be appreciated that, in some embodiments, these steps may be utilized in a manual operation or a combination manual/automatic operation. In addition, it will be appreciated that the disclosed method does not necessarily require the input from all of the tracked components as identified in FIG. 8.


It also will be appreciated that the foregoing description provides examples of the disclosed system and technique. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure more generally. For example, while the foregoing description has been provided with respect to machines used to remove material (e.g., cut or mill rock), the foregoing description is applicable to removing other material (e.g., cutting, drilling, or milling other material) and to machines used to remove other material (e.g., cut or mill other material, such as minerals and metals). Additionally, or alternatively, the foregoing description is applicable to machines used for construction, forestry, and other similar industries and is applicable to avoid collisions between components of these machines. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the disclosure entirely unless otherwise indicated.


Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. Additionally, while the foregoing description has been provided with respect to Cartesian coordinates, the foregoing description may be applicable to other coordinate systems (e.g., the polar coordinate system, the cylindrical coordinate system, the homogeneous coordinate system, etc.).


Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims
  • 1. A machine for removal of material from a surface, the machine comprising: an undercarriage having a front end and a rear end;a plurality of propulsive drive mechanisms, the undercarriage being supported on the plurality of propulsive drive mechanisms to position the machine proximate to the surface;a cutter head;a tool support and positioning assembly supported on the undercarriage, the tool support and positioning assembly being moveable relative to the undercarriage, the cutter head being disposed on the tool support and positioning assembly and moveable relative to the undercarriage at a speed;at least one support position sensor associated with the tool support and positioning assembly, the at least one support position sensor being adapted to dynamically determine a position of the tool support and positioning assembly;a gathering head coupled to the undercarriage, the gathering head being disposed at the front end of the undercarriage; anda controller configured to: receive a tool support position signal from the at least one support position sensor,determine respective positional coordinate representations of the gathering head, the tool support and positioning assembly, and the cutter head within a coordinate system,determine if any of the gathering head, the tool support and positioning assembly, and the cutter head are within a preset collision slowdown zone within the coordinate system based on the respective positional coordinate representations,determine if any of the gathering head, the tool support and positioning assembly, and the cutter head are within a preset collision shutdown zone within the coordinate system based on the respective positional coordinate representations,if any of the gathering head, the tool support and positioning assembly, and the cutter head is within said preset collision slowdown zone, then restrict the speed of the gathering head, the tool support and positioning assembly, and the cutter head in a direction of collision within said preset collision slowdown zone to a reduced speed within said preset collision slowdown zone,if any of the gathering head, the tool support and positioning assembly, and the cutter head is within said preset collision shutdown zone, then stop movement of the gathering head, the tool support and positioning assembly, and the cutter head in the direction of collision within the preset collision shutdown zone, andif none of the gathering head, the tool support and positioning assembly, and the cutter head is within at least one of the preset collision slowdown zone and the preset collision shutdown zone, then permit full speed movement of the tool support and positioning assembly.
  • 2. The machine of claim 1 wherein the controller includes an automatic operation, wherein the controller is configured to restrict the speed movement of the tool support and positioning assembly in a direction other than the direction of collision when any of the gathering head, the tool support and positioning assembly, and the cutter head is within said preset collision slowdown zone.
  • 3. The machine of claim 1 wherein the controller includes a manual operation, wherein the controller is configured to permit full speed movement of the tool support and positioning assembly in directions other than the direction of collision when any of the gathering head, the tool support and positioning assembly, and the cutter head is within said preset collision slowdown zone.
  • 4. The machine of claim 1 wherein the coordinate system is a Cartesian coordinate system.
  • 5. The machine of claim 1 wherein the tool support and positioning assembly includes at least two of a longitudinally movable boom infeed extension, a rollover joint, and a cantilevered lift arm.
  • 6. The machine of claim 1 further including at least one hydraulic cylinder associated with the movement of the tool support and positioning assembly, and wherein the at least one support position sensor is associated with the at least one hydraulic cylinder.
  • 7. The machine of claim 1 wherein the controller is configured to determine positional coordinate representations of a protective envelope above the gathering head in determining the positional coordinate representations of the gathering head.
  • 8. The machine of claim 1 further including at least one moveable stabilizer associated with an underside of the gathering head, and at least one stabilizer position sensor associated with the at least one stabilizer, wherein the controller is further configured to receive a stabilizer position signal from the at least one stabilizer position sensor,determine respective positional coordinate representations of the gathering head and the at least one stabilizer within the coordinate system,determine if any of the gathering head and the at least one stabilizer are within a second preset collision slowdown zone based upon the respective positional coordinate representations of the gathering head and the at least one stabilizer within the coordinate system,determine if any of the gathering head and the at least one stabilizer are within a second preset collision shutdown zone based upon the respective positional coordinate representations of the gathering head and the at least one stabilizer within the coordinate system,if any of the gathering head and the at least one stabilizer is within said second preset collision slowdown zone, then restrict the speed of the gathering head and the at least one stabilizer in a direction of collision within said second preset collision slowdown zone to a reduced speed within said second preset collision slowdown zone,if any of the gathering head and the at least one stabilizer is within said second preset collision shutdown zone, then stop movement of the at least one stabilizer in the direction of collision within the second preset collision shutdown zone, andif none of the gathering head and the at least one stabilizer is within at least one of the second preset collision slowdown zone and the second preset collision shutdown zone, then permit full speed movement of the stabilizer.
  • 9. The machine of claim 8 including at least two stabilizers associated with the underside of the gathering head and at least two stabilizer position sensors, the controller being configured to received stabilizer position signals from the at least two stabilizer position sensors.
  • 10. A method of avoiding collisions between components of a machine having a gathering head, a cutter head, and a movable tool support and positioning assembly, the tool support and positioning assembly being moveable relative to the gathering head, the cutter head being disposed on the tool support and positioning assembly and moveable relative to the gathering head at a speed, the method comprising: receiving at least one tool support position signal from at least one support position sensor,determining respective positional coordinate representations of the gathering head, the tool support and positioning assembly, and the cutter head within a coordinate system,determining at least one of: if any of the gathering head, the tool support and positioning assembly, and the cutter head are within a preset collision slowdown zone within the coordinate system based upon the respective positional coordinate representations, andif any of the gathering head, the tool support and positioning assembly, and the cutter head are within a preset collision shutdown zone within the coordinate system based upon the respective positional coordinate representations,if any of the gathering head, the tool support and positioning assembly, and the cutter head is within said preset collision slowdown zone, then restricting the speed of the gathering head, the tool support and positioning assembly, and the cutter head in a direction of collision within said preset collision slowdown zone to a reduced speed within said preset collision slowdown zone,if any of the gathering head, the tool support and positioning assembly, and the cutter head is within said preset collision shutdown zone, then stopping movement of the tool support and positioning assembly in the direction of collision within the preset collision shutdown zone, andif none of the gathering head, the tool support and positioning assembly, and the cutter head is within at least one of the preset collision slowdown zone and the preset collision shutdown zone, then permitting full speed movement of the tool support and positioning assembly.
  • 11. The method of claim 10 wherein the machine is automatically operable, and the method further includes restricting the speed movement of the tool support and positioning assembly in a direction other than the direction of collision when any of the gathering head, the tool support and positioning assembly, and the cutter head is within said preset collision slowdown zone.
  • 12. The method of claim 10 wherein the machine is manually operable, and the method further includes permitting full speed movement of the tool support and positioning assembly in directions other than the direction of collision when any of the gathering head, the tool support and positioning assembly, and the cutter head is within said preset collision slowdown zone.
  • 13. The method of claim 10 wherein the coordinate system is a Cartesian coordinate system.
  • 14. The method of claim 10 wherein the step of receiving a tool support position signal includes receiving signals from at least two of a boom sensor, a swing sensor, a lift sensor, and a rollover joint sensor.
  • 15. The method of claim 10 wherein the step of determining positional coordinate representations of the gathering head includes establishing positional coordinate representations of a protective envelope above the gathering head.
  • 16. The method of claim 10 wherein the machine further includes at least one moveable stabilizer associated with an underside of the gathering head, and at least one stabilizer position sensor associated with the at least one stabilizer, and wherein the method further includes receiving a stabilizer position signal from the at least one stabilizer position sensor,determining respective positional coordinate representations of the gathering head and the at least one stabilizer within the coordinate system,determining if any of the gathering head and the at least one stabilizer are within a second preset collision slowdown zone within the coordinate system based upon the respective positional coordinate representations of the gathering head and the at least one stabilizer within the coordinate system,determining if any of the gathering head and the at least one stabilizer are within a second preset collision shutdown zone within the coordinate system based upon the respective positional coordinate representations of the gathering head and the at least one stabilizer within the coordinate system,if any of the gathering head and the at least one stabilizer is within said second preset collision slowdown zone, then restricting the speed of the gathering head and the at least one stabilizer in a direction of collision within said second preset collision slowdown zone to a reduced speed within said second preset collision slowdown zone,if any of the gathering head and the at least one stabilizer is within said second preset collision shutdown zone, then stopping movement of the at least one stabilizer in the direction of collision within the second preset collision shutdown zone, andif none of the gathering head and the at least one stabilizer is within at least one of the second preset collision slowdown zone and the second preset collision shutdown zone, then permitting full speed movement of the stabilizer.
  • 17. The machine of claim 17 wherein the step of receiving a stabilizer position signal includes receiving stabilizer position signals from at least two stabilizer position sensors associated with at least two stabilizers, respectively.
  • 18. A machine for underground milling of a milling wall, the machine comprising: an undercarriage having a front end and a rear end;a cutter head;a tool support and positioning assembly supported on the undercarriage;a gathering head coupled to the undercarriage; anda controller configured to: determine coordinates of the tool support and positioning assembly, and the cutter head within a coordinate system,determine coordinates of the gathering head within the coordinate system,determine at least one of: if any of the gathering head, the tool support and positioning assembly, and the cutter head are within a preset collision slowdown zone within the coordinate system, andif any of the gathering head, the tool support and positioning assembly, and the cutter head are within a preset collision shutdown zone within the coordinate system,if any of the gathering head, the tool support and positioning assembly, and the cutter head is within said preset collision slowdown zone, then restrict the speed of the gathering head, the tool support and positioning assembly, and the cutter head within said preset collision slowdown zone to a reduced speed in a direction of collision within said preset collision slowdown zone,if any of the gathering head, the tool support and positioning assembly, and the cutter head is within said preset collision shutdown zone, then stop movement of the tool support and positioning assembly in the direction of collision within the preset collision shutdown zone, andif none of the gathering head, the tool support and positioning assembly, and the cutter head is within at least one of the preset collision slowdown zone and the preset collision shutdown zone, then permit full speed movement of the tool support and positioning assembly.
  • 19. The machine of claim 19 wherein the tool support and positioning assembly is moveable relative to the undercarriage, the cutter head being disposed on the tool support and positioning assembly and moveable at a speed relative to the undercarriage, the tool support and positioning assembly including a boom infeed extension and a cantilevered lift arm; the method further including at least one boom actuator associated with the boom infeed extension, at least one lift actuator associated with the cantilevered lift arm, a boom sensor associated with the at least one boom actuator, the boom sensor being adapted to dynamically determine a position of the at least one boom actuator, and a lift sensor associated with the at least one lift actuator, the lift sensor being adapted to dynamically determine a position of the at least one lift actuator; the gathering head having an upper surface, the controller being configured to receive a boom position signal from the boom sensor, and receive a lift position signal from the lift sensor.
  • 20. The machine of claim 19 additionally including left and right stabilizers associated with an underside of the gathering head, and left and right stabilizer position sensors associated with the left and right stabilizers, respectively, wherein the controller is further configured to receive left and right stabilizer position signals from the left and right stabilizer position sensors,determine respective Cartesian coordinates of the gathering head and the left and right stabilizers within the Cartesian coordinate system,determine if any of the gathering head and either of the left and right stabilizers are within a second preset collision slowdown zone,determine if any of the gathering head and either of the left and right stabilizers are within a second preset collision shutdown zone,if any of the gathering head and either of the left and right stabilizers is within said second preset collision slowdown zone, then restrict the speed of at least one of the left and right stabilizers in a direction of collision within said second preset collision slowdown zone to a reduced speed within said second preset collision slowdown zone,if any of the gathering head and either of the left and right stabilizers is within said second preset collision shutdown zone, then stop movement of at least one of the left and right stabilizers in the direction of collision within the second preset collision shutdown zone, andif none of the gathering head and either of the left and right stabilizers is within at least one of the second preset collision slowdown zone and the second preset collision shutdown zone, then permit full speed movement of the left and right stabilizers.