Mill planer with height measurement system based on fluid flow

Abstract

A milling machine can have a frame, a milling drum attached to the frame, and a ground-engaging track supporting the frame and propelling the milling machine in a forward or rearward direction. The milling machine can have a reservoir storing hydraulic fluid. The milling machine can also have at least one actuator connecting the frame to the track. The actuator can adjust a height of the frame relative to a ground surface. A fluid conduit can connect the reservoir to the actuator. The milling machine can have a flow sensor in the fluid conduit. The flow sensor can determine a flow parameter associated with a flow of hydraulic fluid into or out of the actuator. The milling machine can also have a controller determining the height of the frame relative to the ground surface based on the flow parameter.

Description

Technical Field

[0001] This disclosure generally relates to a milling machine, and more specifically to a milling machine having a height measurement system based on fluid flow. Background Technology

[0002] Road surfaces typically consist of the top layer of asphalt or concrete on which vehicles travel. Over time, road surfaces may wear down or become damaged, for example, due to the formation of potholes, cracks, and ruts. Damaged road surfaces can, in turn, cause damage to vehicles traveling on them. Damaged road surfaces can be partially repaired by filling potholes, cracks, and / or ruts. However, it is generally desirable to replace worn or damaged road surfaces with entirely new road surfaces. This is typically achieved by removing the asphalt or concrete layer from the road and repaving it with a new layer of asphalt or concrete.

[0003] Milling machines are typically used to remove layers of asphalt or concrete from road surfaces. A typical milling machine consists of a frame supported on wheels or tracks by height-adjustable outriggers, and includes a milling drum attached to the frame. As the milling machine travels over an existing road surface, teeth or cutting tools on the rotating milling drum contact the road surface and tear away the road layers. The milling drum chamber typically surrounds the milling drum to contain the milled material. The milled material is usually conveyed to a nearby vehicle using a conveyor system, which removes the material from the work site. After the milling process, a new layer of asphalt or concrete can be applied to the milled road surface to create a new road surface.

[0004] In another application, it is sometimes desirable to stabilize or rebuild the superstructure of a road or work site. This is typically achieved by removing the superstructure, mixing it with stabilizing components such as cement, ash, lime, etc., and depositing the mixture back onto the top of the road or work site. Milling machines, such as stabilizers or fillers, are commonly used for this purpose. Such milling machines may also include a frame supported on tracks or wheels by height-adjustable outriggers and include a milling drum attached to the frame. The milling drum is enclosed within a chamber. Cutting tools or teeth on the milling drum tear through the ground and push the removed material toward the rear of the chamber. Stabilizing components and / or water are mixed with the milled material, which is then deposited back onto the ground toward the rear of the chamber.

[0005] In the two types of milling machines discussed above, it is typically necessary to position the frame at a desired height and / or orientation relative to the ground surface. For example, it may be necessary to orient the frame at a predetermined tilt relative to the ground surface to achieve a corresponding tilt of the milled surface. It may also be necessary to raise the frame to a desired height to perform maintenance operations. Therefore, it is desirable to accurately determine the height and / or tilt of the frame relative to the ground surface.

[0006] Externally attached sensors, such as ultrasonic sensors, can be used to determine and adjust the height and orientation of the frame. However, ultrasonic sensors may not provide the desired level of accuracy. Furthermore, using such external sensors requires additional and potentially inconvenient steps to connect them to the milling machine and its control system. Proximity sensors located on the outriggers may also be used to position the frame. However, based on the location of the proximity sensor on the machine, it may only position the frame at discrete heights above the ground surface. Therefore, it is desirable to equip the milling machine with a height sensor that can help accurately position the frame relative to the ground surface at any desired height and / or orientation.

[0007] The milling machine and / or fluid flow-based height measurement system disclosed herein solve one or more of the above-mentioned problems and / or other problems in the art. Summary of the Invention

[0008] In one aspect, this disclosure relates to a milling machine. The milling machine may include a frame and a milling drum attached to the frame. The milling machine may also include a plurality of ground-engaging tracks configured to support the frame and propel the milling machine in a forward or backward direction. The milling machine may include a tank configured to store hydraulic fluid. The milling machine may also include at least one actuator connecting the frame to the tracks. The at least one actuator may be configured to adjust the height of the frame relative to a ground surface. The milling machine may include a fluid conduit connecting the tank to the at least one actuator. The milling machine may also include a flow sensor disposed in the fluid conduit. The flow sensor may be configured to determine flow parameters associated with the flow of hydraulic fluid entering or leaving the at least one actuator. The milling machine may include a controller configured to determine the height of the frame relative to the ground surface based on the flow parameters.

[0009] In another aspect, this disclosure relates to a milling machine. The milling machine may include a frame. The milling machine may also include a left front track disposed adjacent to the front end of the frame, a right front track disposed adjacent to the front end and spaced apart from the left front track, and at least one rear track disposed adjacent to the rear end of the frame. Furthermore, the milling machine may include a left front actuator connecting the frame and the left front track, a right front actuator connecting the frame and the right front track, and a rear actuator connecting the frame and at least one rear track. Each of the left front actuator, right front actuator, and rear actuator may be configured to selectively adjust the height of the frame relative to the left front track, right front track, and at least one rear track, respectively. The milling machine may include a milling drum connected to the frame and disposed between the front end and the rear end. The milling machine may also include an engine configured to rotate the milling drum and propel the left front track, right front track, and at least one rear track in a forward or rearward direction. The milling machine may include at least one flow sensor configured to determine flow parameters associated with the flow of hydraulic fluid entering or leaving at least one of the left front actuator, right front actuator, and rear actuator. Furthermore, the milling machine may include a controller configured to determine the height of the frame relative to the ground surface based on the flow parameters. Attached Figure Description

[0010] Figure 1 This is an illustration of an exemplary milling machine;

[0011] Figure 2 This is an illustration of another exemplary milling machine;

[0012] Figure 3A yes Figure 1 and 2 A partial cross-sectional view of an exemplary support column of a milling machine;

[0013] Figure 3B yes Figure 1 and 2 A partial cross-sectional view of another exemplary support column of a milling machine;

[0014] Figure 4A yes Figure 1 and 2 A schematic diagram of an exemplary hydraulic circuit for a milling machine;

[0015] Figure 4B yes Figure 1 and 2 A schematic diagram of another exemplary hydraulic circuit for a milling machine;

[0016] Figure 5 This illustrates the pressure drop, current, voltage, or angular velocity associated with the exemplary disclosed flow meter. Figure 4A and 4B An exemplary graph showing the correlation between the flow rates of hydraulic fluid in a hydraulic circuit;

[0017] Figure 6 yes Figure 1 and 2 An exemplary illustration of a milling machine based on a fluid flow height sensor;

[0018] Figure 7 This is an exemplary method for determining the height of the milling machine frame relative to the ground surface; and

[0019] Figure 8 This is another exemplary method for determining the height of the milling machine frame relative to the ground surface. Detailed Implementation

[0020] Figure 1 and 2 Exemplary milling machines 10 and 20 are shown respectively. In such... Figure 1 In one exemplary embodiment shown, the milling machine 10 may be a cold planer, which may also be referred to as a cold milling machine, a soil ripper, a profile planer, etc. The milling machine 10 may include a frame 22 extending from a first end 24 to a second end 26 disposed opposite to the first end 24. In some exemplary embodiments, the first end 24 may be a front end, while the second end 26 may be a rear end of the frame 22. The frame 22 may have any shape (e.g., rectangular, triangular, square, etc.).

[0021] Frame 22 can be supported on one or more propulsion devices. For example, such as Figure 1 As shown, frame 22 can be supported on propulsion devices 28, 30, 32, and 34. Propulsion devices 28, 30, 32, and 34 can be equipped with electric or hydraulic motors, which can provide movement to propel the machine 10 forward or backward. Figure 1 In one exemplary embodiment shown, the propulsion devices 28, 30, 32, and 34 may be in the form of tracks, which may include, for example, sprockets, idler wheels, and / or one or more rollers capable of supporting continuous tracks. However, it is contemplated that the propulsion devices 28, 30, 32, and 34 of the milling machine 10 may be in the form of wheels (see [link to documentation]). Figure 2 In this disclosure, the terms track and wheel will be used interchangeably, and the other of the two terms will be included.

[0022] Tracks 28 and 30 can be positioned adjacent to the first end 24 of frame 22, and tracks 32 and 34 can be positioned adjacent to the second end 26 of frame 22. Track 28 can be spaced apart from track 30 along the width direction of frame 22. Similarly, track 32 can be spaced apart from track 34 along the width direction of frame 22. Figure 1In one exemplary embodiment shown, track 28 may be the left front track, track 30 may be the right front track, track 32 may be the left rear track, and track 34 may be the right rear track. Some or all of the propulsion devices 28, 30, 32, and 34 may also be steerable, thereby allowing the machine 10 to turn right or left during forward or backward movement on the ground surface 64. Although Figure 1 The milling machine 10 is shown to include four tracks 28, 30, 32, 34, but it is envisioned that in some exemplary embodiments, the milling machine 10 may have only one rear track 32 or 34, which may be positioned substantially centered along the width of the frame 22.

[0023] Frame 22 can be connected to tracks 28, 30, 32, 34 via one or more outrigger posts 36, 38, 40, 42. For example, as Figure 1 As shown, frame 22 can be connected to the left front track 28 via outrigger posts 36 and to the right front track 30 via outrigger posts 38. Similarly, frame 22 can be connected to the left rear track 32 via outrigger posts 40 and to the right rear track 34 via outrigger posts 42. One or more of outrigger posts 36, 38, 40, and 42 can be height-adjustable, such that the height of frame 22 relative to one or more of tracks 28, 30, 32, and 34 can be increased or decreased by adjusting the length of one or more outrigger posts 36, 38, 40, and 42, respectively. It should be understood that adjusting the height of frame 22 relative to one or more of tracks 28, 30, 32, and 34 will also adjust the height of frame 22 relative to the ground surface 64 on which tracks 28, 30, 32, and 34 can be supported.

[0024] Machine 10 may include a milling drum 50, which may be attached to frame 22 between front end 24 and rear end 26. Milling drum 50 may include cutting tools 52 (or teeth 52) configured to cut and tear a predetermined thickness of road or ground. The height of milling drum 50 relative to ground surface 64 can be adjusted by adjusting the height of one or more outriggers 36, 38, 40, 42. When milling drum 50 rotates, the teeth 52 of milling drum 50 may contact the ground or road surface, thereby tearing or cutting the ground or road surface. Milling drum 50 may be enclosed within a drum chamber 54, which may facilitate the containment of material removed from the ground or road surface by the teeth 52. Machine 10 may include one or more conveyors 56, 58, which may facilitate the transport of material removed by milling drum 50 to adjacent vehicles, such as dump trucks.

[0025] The milling machine 10 may include an engine 60 attachable to the frame 22. The engine 60 may be any suitable type of internal combustion engine, such as a gasoline, diesel, natural gas, or hybrid engine. However, it is contemplated that in some exemplary embodiments, the engine 60 may be electrically driven. The engine 60 may be configured to deliver rotational power output to one or more hydraulic electric motors associated with propulsion devices 28, 30, 32, 34, to the milling drum 50, and to one or more transmitters 56, 58. The engine 60 may also be configured to deliver electricity to operate one or more other components or accessory devices associated with the milling machine 10 (e.g., pumps, fans, motors, generators, belt drives, transmissions, etc.).

[0026] The milling machine 10 may include an operator platform 62 attachable to the frame 22. In some exemplary embodiments, the operator platform 62 may be in the form of an open platform, which may or may not include a roof. In other exemplary embodiments, the operator platform 62 may be in the form of a partially or completely enclosed cabin. Figure 1 As shown, the operator platform 62 may be located at a height “H” above the ground surface 64. In some exemplary embodiments, the height H may be between approximately 2 feet and 10 feet above the ground surface 64. The operator platform 62 may include one or more controllers 66, which may be used by an operator to operate and / or control the milling machine 10. The controller 66 may include one or more input devices 66, which may take the form of buttons, switches, sliders, joysticks, rollers, touch screens, or other input / output or interface devices. The milling machine 10 may include a display 68 located in the operator platform 62. The display 68 may be configured to display information, data, and / or measurements obtained from one or more sensors of the milling machine 10. The display 68 may also be configured to display diagnostic results, errors, and / or alarms. The display 68 may be a cathode ray tube (CRT) monitor, a liquid crystal display (LCD), a light-emitting diode (LED) display, a touch screen display, or any other type of display.

[0027] The milling machine 10 may also include a controller 70, which is configured to receive inputs, data, and / or signals from one or more input devices 66 and / or other sensors associated with the milling machine 10, and to control the operation of one or more components (e.g., engine 60, milling drum 50, propellers 28, 30, 32, 34, transmitters 56, 58, etc.). The controller 70 may include or be associated with one or more processors, memory devices 72, and / or communication devices. The controller 70 may embody a single microprocessor or multiple microprocessors, digital signal processors (DSPs), application-specific integrated circuit devices (ASICs), etc. Many commercially available microprocessors may be configured to perform the functions of the controller 70. Various other known circuits may be associated with the controller 70, including power supply circuits, signal conditioning circuits, and communication circuits. The controller 70 may also include one or more internal timers configured to monitor the time at which the controller 70 may receive signals from one or more sensors or the time at which the controller 70 may issue command signals to one or more components of the milling machine 10.

[0028] One or more memory devices 72 associated with controller 70 may store, for example, data and / or one or more control routines or instructions. The one or more memory devices 72 may be embodied in a non-transitory computer-readable medium, such as a random access memory (RAM) device, a NOR or NAND flash memory device, and a read-only memory (ROM) device, CD-ROM, hard disk, floppy disk drive, optical media, solid-state storage media, etc. Controller 70 may receive one or more input signals from one or more input devices 66 and may execute routines or instructions stored in one or more memory devices 72 to generate one or more command signals and deliver them to one or more of the propulsion systems 28, 30, 32, 34, engine 60, milling drum 50, transmitters 56, 58, or other components of milling machine 10.

[0029] Figure 2 Another exemplary embodiment of the milling machine is shown. Figure 2 In one exemplary embodiment shown, the milling machine 20 can be a soil filler, also known as a soil stabilizer, filler machine, road filler, etc. Like the milling machine 10, the milling machine 20 may include a frame 22 and wheel-type propulsion devices 28, 30, 32. Figure 2 (Not visible in the center), 34, and support columns 36, 38, 40, 42. In some exemplary embodiments, one or more support columns 36, 38, 40, 42 may be height-adjustable, such that the height of the frame 22 relative to one or more of the wheels 28, 30, 32, 34 can be increased or decreased by adjusting the length of one or more support columns 36, 38, 40, 42 respectively. Figure 2 As shown, outrigger column 36 connects frame 22 to left front wheel 28, outrigger column 38 connects frame 22 to right front wheel 30, and outrigger column 40 connects frame 22 to left rear wheel 32. Figure 2 (Not visible in the middle), and the outrigger column 42 connects the frame 22 to the right rear wheel 34. Although the milling machine 20 is already... Figure 2 The milling machine 20 is shown as including wheels 28, 30, 32, and 34, but it is contemplated that the milling machine 20 may instead include tracks 28, 30, 32, and 34. One or more of the wheels 28, 30, 32, and 34 may be steerable, thereby allowing the milling machine 20 to turn to the right or left during forward or backward movement on the ground surface 64.

[0030] The milling drum 50 of the milling machine 20 can be located between the first end 24 and the second end 26. In such a case... Figure 2 In one exemplary embodiment shown, the milling drum 50 of the milling machine 20 may not be directly attached to the frame 22. Instead, as shown... Figure 2 As shown, the milling drum 50 of the milling machine 20 can be attached to the frame 22 via an arm 74. The arm 74 may include a pair of arms disposed on either side of the milling machine 20 (in... Figure 2 (Only one of them is visible in the image). Arm 74 may be pivotally attached to frame 22 and may be configured to rotate relative to frame 22. One or more actuators may be connected between frame 22 and arm 74 and may be configured to move arm 74 relative to frame 22. Thus, unlike milling machine 10, the milling drum 50 of milling machine 20 may move relative to frame 22. However, it is contemplated that in other exemplary embodiments, milling drum 50 may be directly attached to frame 22 of machine 20 in a manner similar to that described above for machine 10.

[0031] The milling drum 50 of the milling machine 20 may include cutting tools 52 (or teeth 52). The height of the milling drum 50 above the ground surface can be adjusted by rotating the arm 74 relative to the frame 22 and / or by adjusting one or more of the outriggers 36, 38, 40, 42. As the milling drum 50 rotates, the teeth 52 may contact and tear or cut the ground or road surface. The milling drum 50 may be enclosed within a drum chamber 54, which may facilitate the containment of material removed from the ground or road surface by the teeth 52. Rotation of the milling drum 50 may cause the removed material to shift from the adjacent front end 76 of the drum chamber 54 toward the rear end 78 of the drum chamber 54. Stabilizing components such as ash, lime, cement, water, etc., may be mixed with the removed material, and the reconstituted mixture of milled material and stabilizing components may be deposited on the ground surface 64 near the rear end 78 of the drum chamber 54.

[0032] Similar to milling machine 10, milling machine 20 may also include an engine 60, an operator platform 62, one or more control or input devices 66, a display 68, and a controller 70, all of which may have similar structural and functional characteristics as discussed above with respect to milling machine 10. Furthermore, it should be understood that, as used in this disclosure, the terms "front" and "back" are relative terms, which may be determined based on the direction of travel of milling machine 10 or 20. Similarly, it should be understood that, as used in this disclosure, "left" and "right" are relative terms, which may be determined based on the direction of travel facing milling machine 10 or 20.

[0033] Figure 3A This is a partial cross-sectional view of exemplary outrigger posts 36, 38, 40, 42 for a milling machine 10 or 20. Outrigger post 36 may include a first (or upper) section 80 and a second (or lower) section 82. An actuator 88 may be disposed inside or outside the outrigger post 36. The first section 80 may be attached to a frame 22. In one exemplary embodiment, the first section 80 may be rigidly attached to the frame 22. The first section 80 may extend from the frame 22 toward the track 28. In some exemplary embodiments, the first section 80 may also extend into the frame 22 in a direction away from the track 28. Figure 3A As shown, the edge 84 of the first segment 80 may have a height "H1" relative to the frame 22. The second segment 82 may be attached to the track 28 and may extend from the track 28 toward the frame 22. Figure 3A As shown, the edge 86 of the second segment 82 may have a height “H2” relative to the ground surface 64. Heights H1 and H2 may be fixed and may be determined based on the geometry of machine 10 or 20.

[0034] In such Figure 3A In one exemplary embodiment shown, the first segment 80 and the second segment 82 may be hollow cylindrical tubes. However, it is conceivable that the first segment 80 and the second segment 82 may have other non-cylindrical shapes. The first segment 80 and the second segment 82 may be configured to be slidably movable relative to each other. Figure 3A In the exemplary embodiment shown, the second segment 82 may have a smaller cross-section than the first segment 80 and may be received within the first segment 80. However, it is contemplated that in other exemplary embodiments, the first segment 80 may have a smaller cross-section than the second segment 82 and may be received within the second segment 82. The first segment 80 and the second segment 82 may form a variable-height enclosure, and the actuator 88 may be located within the variable-height enclosure. However, it is also contemplated that the actuator 88 may be located outside the enclosure formed by the first segment 80 and the second segment 82.

[0035] Actuator 88 connects frame 22 to track 28. Actuator 88 may include cylinder 90, piston 92, and rod 94. Cylinder 90 extends from frame end 100 connected to frame 22 to track end 102, the track end being disposed between frame 22 and track 28. Piston 92 is slidably disposed within cylinder 90 and may divide cylinder 90 into a front end chamber 96 and a rod end chamber 98. That is, piston 92 is configured to slide within cylinder 90 from adjacent frame end 100 to adjacent track end 102. Front end chamber 96 is disposed closer to frame end 100 of cylinder 90, and rod end chamber 98 is disposed closer to track end 102 of cylinder 90. Rod 94 may be connected to piston 92 at one end. Rod 94 extends from piston 92 through track end 102 of cylinder 90 and may be directly or indirectly connected to track 28 at opposite ends of rod 94. Figure 3A In one exemplary embodiment shown, the rod 94 may be connected to the yoke 162, which in turn may be connected to the track 28. In some exemplary embodiments, the yoke 162 may be fixedly attached to the second section 82 of the outrigger post 36. In other exemplary embodiments, the yoke 162 may be part of the track 28 and may be movably attached to the second section 82. It is also contemplated in some embodiments that the yoke 162 may not be attached to the second section 82.

[0036] Actuator 88 can be a single-acting or double-acting hydraulic actuator. For example, one or both of the front end chamber 96 and the rod end chamber 98 of actuator 88 can be configured to receive and retain hydraulic fluid. One or both of the front end chamber 96 and the rod end chamber 98 can be connected to the reservoir 170 (see [link to reservoir]). Figure 4A , 4B The tank is configured to store hydraulic fluid. Filling the front chamber 96 with hydraulic fluid and / or emptying the rod end chamber 98 with hydraulic fluid allows the piston 92 to slide within the cylinder 90 in the direction indicated by arrow "A" from the frame end 100 toward the track end 102. Movement of the piston in direction A results in an increase in the length of the actuator 88, thereby allowing the first section 80 and the second section 82 to slide relative to each other, thus increasing the height of the outrigger column 36, and consequently also increasing the height of the frame 22 relative to the track 28 or the height of the frame 22 relative to the ground surface 64. Similarly, emptying the front chamber 96 with hydraulic fluid and / or filling the rod end chamber 98 with hydraulic fluid allows the piston 92 to slide within the cylinder 90 in the direction indicated by arrow "B" from the track end 102 toward the frame end 100. Movement of the piston in direction B reduces the length of the actuator 88, thereby reducing the height of the outrigger column 36, which in turn reduces the height of the frame 22 relative to the ground surface 64.

[0037] The outrigger column 36 may include one or more proximity sensors (or switching devices) 104, 106, 108, 110. For example... Figure 3A As shown, proximity sensors 104 and 106 can be attached to the first section 80 of the outrigger post 36. For example, as... Figure 3A As shown, proximity sensor 104 can be attached to the first segment 80 at a distance "h1" relative to frame 22, and proximity sensor 106 can be attached to the first segment 80 at a distance "h2" relative to proximity sensor 104. In an exemplary embodiment, proximity sensors 104, 106 may be beam-break sensors that may include receivers 112, 114 attachable to the first segment 80. Figure 3A In the exemplary embodiment shown, receiver 112 may be attached to the first segment 80 at a distance h1 relative to frame 22, and receiver 114 may be attached to the first segment 80 at a distance h2 relative to receiver 112. Receivers 112 and 114 may be circumferentially positioned on the first segment 80 such that they may receive substantially collimated or focused light beams (e.g., infrared, laser, or any other wavelength) or other electromagnetic radiation from proximity sensors 104 and 106.

[0038] As discussed above, the second segment 82 can be configured to be slidably movable relative to the first segment 80. When the edge 86 of the second segment 82 is positioned adjacent to the proximity sensors 104, 106, the second segment 82 can block the light beam transmitted from the proximity sensors 104, 106, thereby preventing the light beam from being received by the receivers 112, 114, respectively. The proximity sensors 104, 106 can be triggered, and signals can be generated in two scenarios. In the first scenario, the light beam emitted by the proximity sensors 104, 106 can be received by the receivers 112, 114, respectively. When the second segment 82 moves relative to the first segment 80, the edge 86 of the second segment 82 can prevent the receivers 112, 114 from receiving the light beam. The proximity sensors 104 and 106 can generate signals when the light beam previously received by the receivers 112, 114, respectively, is blocked. That is, when there is a transition from an unblocked light beam to a blocked light beam, the proximity sensors 104 and 106 can generate signals. Conversely, in the second scenario, the second segment 82 can be positioned such that the light beam emitted from proximity sensors 104, 106 can be blocked by the second segment 82. When the second segment 82 moves relative to the first segment 80, the previously blocked light beam can be unblocked, allowing receivers 112, 114 to begin receiving the light beam emitted from proximity sensors 104, 106, respectively. Therefore, proximity sensors 104, 106 can generate signals when there is a transition from blocked to unblocked light beam (or vice versa). In both scenarios, proximity sensors 104 and 106 can generate signals when they detect the presence of an edge 86 adjacent to the respective proximity sensor 104, 106.

[0039] Although proximity sensors 104 and 106 have been described above as beam-break sensors, it is contemplated that proximity sensors 104 and 106 may include resistive, inductive, capacitive, optical, or any other type of proximity sensor. For example, as Figure 3A As shown, in some embodiments, proximity sensors 104, 106 may be configured to detect edge 86 or target 116 located on a second segment 82 adjacent to edge 86. Target 116 may extend partially or entirely around the periphery of the second segment 82. In some exemplary embodiments, proximity sensors 104, 106 may be configured to detect edge 86 or target 116 based on changes in inductance, capacitance, or any other electrical characteristics caused by proximity sensors 104 or 106 locating edge 86 or target 116. In other exemplary embodiments, proximity sensors 104, 106 may include imaging devices configured to use image processing techniques to detect edge 86 or target 116 as proximity sensors 104, 106 are positioned.

[0040] In some exemplary embodiments, the outrigger column 36 may additionally or alternatively include proximity sensors 108, 110, which may be attached to the second segment 82. For example, as Figure 3A As shown, proximity sensor 108 can be attached to the second segment 82 at a distance "h3" relative to track 28, and proximity sensor 110 can be attached to the second segment 82 at a distance "h4" relative to proximity sensor 108. The height H3 of track 28 relative to ground surface 64 may be known based on the geometry of machine 10 or 20. In some exemplary embodiments, proximity sensors 108, 110 may be cleavage sensors and may include receivers 118, 120, respectively. When proximity sensors 108, 110 are cleavage sensors, proximity sensors 108, 110 may be attached to the inner surface of the second segment 82. Figure 3AAs shown, receiver 118 can be attached to the second segment 82 at a distance "h3" relative to track 28, and receiver 120 can be attached to the second segment 82 at a distance "h4" relative to proximity sensor 108. Proximity sensors 108, 110 and receivers 118, 120 can have similar structural and functional characteristics to those discussed above with respect to proximity sensors 104, 106 and receivers 112, 114, respectively. When actuator 88 extends or retracts, the light or electromagnetic beam between proximity sensors 104, 106 and receivers 112, 114 can be blocked or unblocked by the track end 102 of cylinder 90, respectively. In some exemplary embodiments where the second segment 82 has a larger size than the first segment 80, the light or electromagnetic beam between proximity sensors 104, 106 and receivers 112, 114 can be blocked or unblocked by the edge 84 of the upper segment 80, respectively. Therefore, controller 70 can be configured to detect the proximity of the track end 102 or edge 84 of the first segment 80 to proximity sensor 108 or 110 based on whether the beam emitted by proximity sensor 108 or 110 is blocked or unblocked. In some exemplary embodiments, target 122 may be attached to the first segment 80 adjacent to edge 84. Target 122 may extend around a portion or all of the perimeter of the first segment 80. Controller 70 can be configured to detect whether target 122 is located adjacent to proximity sensor 108 or 110.

[0041] Although proximity sensors 108 and 110 have been described above as beam break sensors, they may include resistive, inductive, capacitive, optical, or any other type of proximity sensor. For example, proximity sensors 108 and 110 may be configured to detect track end 102, edge 84, or target 122 based on changes in resistance, inductance, capacitance, optical image, or any other electrical characteristic caused by the positioning of track end 102, edge 84, or target 122 by proximity sensors 108 and 110.

[0042] The controller 70 can determine the height of the frame 22 relative to the ground surface 64 based on known distances h1, h2, h3, h4, H1, H2, and / or H3. For example, the controller 70 can determine the height of the outrigger column 36 based on signals received from proximity sensors 104, 106. The controller 70 can receive signals from proximity sensor 104 indicating that the edge 86 of the second segment 82 is located adjacent to proximity sensor 104. The controller 70 can determine that the edge 86 of the second segment 82 is located at a distance h1 from the frame 22 based on the position of proximity sensor 104 relative to the frame 22. Because the edge 86 has a known height H2 relative to the ground surface 64, the controller 70 can determine that the height of the frame 22 relative to the ground surface 64 is approximately h1 + H2. The controller 70 can determine the height of the frame 22 above the ground surface 64 in a similar manner based on signals received from proximity sensor 106.

[0043] As another example, controller 70 can receive a signal from proximity sensor 108 indicating that the edge 84 of the first segment 80 is located near proximity sensor 108. Controller 70 can determine that the edge 84 of the first segment 80 is located at a height h3 + H3 relative to the ground surface 64 based on the position of proximity sensor 108 relative to the ground surface 64. Furthermore, since the height H1 of the edge 84 relative to the frame 22 is known based on the geometry of machine 10 or 20, controller 70 can determine that the height of the frame 22 above the ground surface 64 is approximately H1 + h3 + H3. Controller 70 can similarly determine the height of the frame 22 above the ground surface 64 based on signals received from proximity sensor 110. Therefore, when controller 70 detects that the edge 86 of the second segment 82 or the target 116 is located near proximity sensors 104, 106, controller 70 may be able to determine the height of the frame 22 relative to the ground surface 64. Similarly, when controller 70 detects that the edge 84 of the first segment 80, the target 122, or the track end 102 is near the proximity sensors 108, 110, controller 70 may be able to determine the height of frame 22 relative to ground surface 64. In some exemplary embodiments, controller 70 may also be configured to cause display 68 to display the determined height of frame 22. Although heights h3 and H3 are relative to... Figure 3A The upper surface 164 of the yoke 162 is shown, but it is contemplated that in some exemplary embodiments, the heights h3 and H3 may instead be measured relative to the upper surface 166 of the track 28.

[0044] Figure 3B This is a partial cross-sectional view of another exemplary support column 36, 38, 40, 42 for a milling machine 10 or 20. Figure 3B Many features of the outriggers 36, 38, 40, and 42 shown are similar to Figure 3AThe characteristics of the outrigger columns 36, 38, 40, and 42. In the following disclosure, only those features will be discussed in detail. Figure 3B The embodiments show the characteristics of different support columns 36, 38, 40, and 42. For example... Figure 3B As shown, the outrigger column 36 may include proximity sensors 124, 126 and a target 128. Proximity sensor 124 may be positioned on cylinder 90 at a distance "h5" relative to frame 22. Proximity sensor 126 may be positioned on cylinder 90 at a distance "h6" relative to proximity sensor 126. Proximity sensors 124, 126 may have similar structural and functional characteristics to those discussed above regarding one or more of proximity sensors 104, 106, 108, 110. Therefore, for example, when proximity sensors 124, 126 are break-beam sensors, outrigger column 36 may include, for example, receivers 130, 132 positioned on the first segment 80 at distances h5 and h6, respectively. In other exemplary embodiments, proximity sensors 124, 126 can detect the presence of an edge 86 of the second segment 82 or a target 128 adjacent to the edge 86 of the second segment 82, as discussed above with respect to proximity sensors 104, 106, 108, 110, based on changes in resistance, inductance, capacitance, optical imagery, etc. The target 128 may extend partially or entirely around the perimeter of the second segment 82. Proximity sensors 124, 126 can send signals to controller 70, enabling controller 70 to determine that the edge 86 and / or the target 128 may be located adjacent to one of proximity sensors 124, 126. Based on known distances h5, h6, and based on the geometry of machine 10 or 20, controller 70 can determine the height of frame 22 relative to ground surface 64 when the edge 86 and / or the target 128 is located adjacent to proximity sensors 124, 126. Although proximity sensors 124, 126 have... Figure 3B The sensor is shown attached to cylinder 90, but it is envisioned that proximity sensors 124 and 126 may be attached to rod 94 separately or alternatively.

[0045] Although the above text has already mentioned targets 116 and 122 ( Figure 3A ) and target 128 ( Figure 3B The diagram shows and describes the location near edge 84 or 86, but it is contemplated that targets 116, 122, and 128 could be located at any known distance from edge 84 or 86. Furthermore, although in Figure 3A and Figure 3BAs shown and described above, only proximity sensors 104, 106, 108, 110, 124, 126, receivers 112, 114, 118, 120, 130, 132, and targets 116, 122, 128 are considered. However, it is contemplated that one or more outrigger posts 36, 38, 40, 42 may include any number of proximity sensors, receivers, and / or targets. It is also contemplated that one or more outrigger posts 36, 38, 40, 42 may include some, but not all, of the proximity sensors 104, 106, 108, 110, 124, 126, receivers 112, 114, 118, 120, 130, 132, and / or targets 116, 122, 128, and their associated height relative to the upper edge 164 of the frame 22, the yoke 162, and / or the upper surface 166 of the track 28. In some exemplary embodiments, instead of attaching to the outriggers 36 or actuators 88, one or more of the proximity sensors 104, 106, 108, 110, 124, 126, receivers 112, 114, 118, 120, 130, 132, and / or targets 116, 122, 128 may be attached to other structural members (e.g., sliding rods, tubes, etc.) disposed within the enclosure formed by the first section 80 and the second section 82. It is also envisioned that these sliding structural members may be attached to the frame 22 and / or the tracks 28.

[0046] In some exemplary embodiments, controller 70 is also envisioned to be configured to stop movement (e.g., extraction or retraction) of actuator 88 based on input received from one or more input devices 66. Controller 70 may be configured to stop movement of actuator 88 by stopping the flow of hydraulic fluid into or out of front end chamber 96 or rod end chamber 98. For example, input device 66 may be configured to specify a desired height of frame 22 relative to ground surface 64 with reference to the known position of one or more proximity sensors 104, 106, 108, 110, 124, and / or 126. Controller 70 may be configured to stop movement of actuator 88 upon receiving a signal indicating that edge 84, edge 86, or track end 102 is adjacent to the location of proximity sensor 104, 106, 108, 110, 124, or 126. For example, proximity sensor 106 may correspond to a service height (e.g., the height of frame 22 suitable for performing maintenance operations). When the operator uses input device 66 to specify that frame 22 should be raised to service height, controller 70 can be configured to stop the movement of actuator 88 when it receives a signal from proximity sensor 106 that the edge 86 of second segment 82 is located near proximity sensor 106.

[0047] In some exemplary embodiments, the positions of one or more of the proximity sensors 104, 106, 108, 110, 124, 126, receivers 112, 114, 118, 120, 130, 132, and / or targets 116, 122, 128 may not be fixed. Instead, the proximity sensors 104, 106, 108, 110, 124, 126, receivers 112, 114, 118, 120, 130, 132, and / or targets 116, 122, 128 may be movable and can be configured to be positioned at any desired distance relative to the frame 22 or track 28. For example, in some embodiments, proximity sensors 104, 106, 108, 110, 124, 126, receivers 112, 114, 118, 120, 130, 132, and / or targets 116, 122, 128 may be associated with servo motors, rack and pinion arrangements, line and pulley arrangements, or other mechanical devices configured to allow proximity sensors 104, 106, 108, 110, 124, 126, receivers 112, 114, 118, 120, 130, 132, and / or targets 116, 122, 128 to be positioned relative to frame 22 or track 28 at any desired distance. For instance, an operator may use one or more input devices 66 to specify a desired distance to one or more proximity sensors, receivers, or targets. The controller 70 may receive signals from one or more input devices 66 and may be configured to operate one or more servo motors, rack and pinion arrangements, line and pulley arrangements or other mechanical devices to move one or more proximity sensors 104, 106, 108, 110, 124, 126, receivers 112, 114, 118, 120, 130, 132 and / or targets 116, 122, 128 to a position specified by the operator.

[0048] Furthermore, although the foregoing description refers to outrigger posts 36 and tracks 28, each of the outrigger posts 38, 40, and 42 connected to tracks 30, 32, and 34 respectively may have similar structural and functional characteristics to those described above regarding outrigger posts 36 and tracks 28. Therefore, for example, each of outrigger posts 38, 40, and 42 may include any number of proximity sensors, receivers, and / or targets, including, for example, proximity sensors 104, 106, 108, 110, 124, and 126, receivers 112, 114, 118, 120, 130, and 132, and / or targets 116, 122, and 128. It is also contemplated that distances h1, h2, h3, h4, h5, and h6 may be equal or unequal, and may be the same or different in outrigger posts 36, 38, 40, and / or 42.

[0049] Figure 4AA schematic diagram of an exemplary hydraulic circuit 140 for a milling machine 10 or 20 is shown. Figure 4A As shown, hydraulic circuit 140 can be applied to milling machine 10 or 20, which may include two front tracks (e.g., left front track 28 and right front track 30) and a rear track 32. Left front track 28 may be connected to frame 22 via outrigger posts 36 (see...). Figure 1 The right front track can be connected to the frame 22 via outrigger column 38 (see...). Figure 1 Furthermore, the rear track 32 can be connected to the frame 22 via the outrigger posts 40 (see...). Figure 1 ).like Figure 4A As shown, the rear track 32 can be positioned adjacent to the second end 26 of the frame 22 and is generally centered along the width "W" of the frame 22.

[0050] The left front track 28 can be connected to the frame 22 via the left front actuator 88, the right front track 30 can be connected to the frame 22 via the right front actuator 134, and the rear track 32 can be connected to the frame 22 via the rear actuator 136. Actuators 88, 134, and 136 can be located inside or outside the outrigger posts 36, 38, and 40, respectively. The left front actuator 88 can be a single-acting or double-acting hydraulic actuator and can have similar characteristics to those described above. Figure 3A and 3B The described structural and functional characteristics. The right front actuator 134 can be a single-acting or double-acting hydraulic actuator and may include a cylinder 142, a piston 144, and a rod 146. The piston 144 may be slidably disposed within the cylinder 142, and the cylinder 142 may be divided into a front end chamber 148 and a rod end chamber 150. That is, the piston 144 may be configured to slide within the cylinder 142. One or both of the front end chamber 148 and the rod end chamber 150 may be configured to retain and receive hydraulic fluid. The cylinder 142 may be connected to the frame 22 adjacent to the front end chamber 148. The rod 146 may be connected to the piston 144 at one end and to the track 30 at the opposite end. Similarly, the rear actuator 136 can be a single-acting or double-acting hydraulic actuator and may include a cylinder 152, a piston 154, and a rod 156. The piston 154 may be slidably disposed within the cylinder 152, and the cylinder 152 may be divided into a front end chamber 158 and a rod end chamber 160. That is, piston 154 may be configured to slide within cylinder 152. One or both of front end chamber 158 and rod end chamber 160 may be configured to retain and receive hydraulic fluid. Cylinder 152 may be connected to frame 22 adjacent to front end chamber 158. Rod 156 may be connected to piston 154 at one end and to track 32 at the opposite end.

[0051] The milling machine 10 or 20 may also include a reservoir 170 configured to store hydraulic fluid. One or more of the front end chambers 96, 148, 158 and / or the rod end chambers 98, 150, 160 may be connected to the reservoir 170 and may receive hydraulic fluid from or direct hydraulic fluid to the reservoir 170. For example, as... Figure 4A As shown, tank fluid conduit 172 connects tank 170 to front chamber 96 of actuator 88, tank fluid conduit 174 connects tank 170 to front chamber 148 of actuator 134, and tank fluid conduit 176 connects tank 170 to front chamber 158 of actuator 136. Therefore, for example, hydraulic fluid can flow from tank 170 to one or more of front chambers 96, 148, 158, or vice versa.

[0052] Flow sensor 178 can be disposed in tank fluid conduit 172 and configured to determine flow parameters associated with the hydraulic fluid flow between tank 170 and front chamber 96. Flow sensor 180 can be disposed in tank fluid conduit 174 and configured to determine flow parameters associated with the hydraulic fluid flow between tank 170 and front chamber 148. Flow sensor 182 can be disposed in tank fluid conduit 176 and configured to determine flow parameters associated with the hydraulic fluid flow between tank 170 and front chamber 158. Figure 4A As shown, for example, flow sensor 178 can be a left front flow sensor, flow sensor 180 can be a right front flow sensor, and flow sensor 182 can be a rear flow sensor.

[0053] In such Figure 4A In one exemplary embodiment shown, flow sensors 178, 180, and 182 may be flow meters configured to measure the velocity or flow rate of hydraulic fluid flowing in tank fluid conduits 172, 174, and 176, respectively. Therefore, the flow parameters of these flow meters may include one of the velocity or flow rate of the hydraulic fluid in tank fluid conduits 172, 174, and 176. It is conceivable that one or more of flow sensors 178, 180, and 182 may be differential pressure flow meters, positive displacement flow meters, velocity flow meters, or any other type of fluid flow meter. When one or more of flow sensors 178, 180, and 182 are differential pressure flow meters, a pressure sensor may be associated with the flow meter to determine the pressure drop at a contraction such as an orifice, venturi tube, flow tube, nozzle, etc. The pressure sensor may transmit a signal to controller 70.

[0054] When one or more flow sensors 178, 180, 182 are positive displacement flow meters, the hydraulic fluid flowing through the flow sensors can displace a valve element within the flow sensors. The movement of the valve element can be converted into an electrical signal using a rotary or linear encoder, or other sensors that can convert movement into an electrical signal. These electrical signals can be transmitted from the flow sensors 178, 180, 182 to the controller 70. In some exemplary embodiments where the flow sensors 178, 180, or 182 are turbine flow meters or rotary vane flow meters, the angular velocity of the turbine or rotary vane can correspond to the velocity of the fluid flowing through the flow sensors 178, 180, or 182. The flow rate of the hydraulic fluid in such flow meters can be determined based on the determined velocity and the cross-sectional area of ​​the flow. It is conceivable that when the flow sensors 178, 180, or 182 are turbine flow meters or rotary vane flow meters, electronic sensors or pickups associated with the flow sensors can transmit signals indicating the angular velocity of the turbine and / or rotary vanes to the controller 70. The milling machine 10 or 20 may include additional fluid conduits, control valves, pressure relief valves, pumps, filters, flow sensors, and / or other hydraulic components connecting actuators 88, 134, and / or 136 to the reservoir 170. For example, it is contemplated that rod end chambers 98, 150, and 160 may also be connected to the reservoir 170 via fluid conduits, which may include flow sensors, for example, determining the flow rate of hydraulic fluid between the reservoir 170 and one or more of the rod end chambers 98, 150, and 160. For the sake of brevity and clarity, a discussion of these additional hydraulic components is omitted in this disclosure.

[0055] Figure 5 A schematic diagram 500 illustrates exemplary variations in the flow rate of one or more flow sensors 178, 180, 182 relative to pressure drop, current, voltage, or angular velocity. For example, as shown in line 502, the flow rate of hydraulic fluid through flow sensors 178, 180, or 182 can vary linearly with the amount of pressure drop, current, voltage, or angular velocity. In other embodiments, the flow rate of hydraulic fluid through control valves 178, 180, or 182 can vary non-linearly with the amount of pressure drop, current, voltage, or angular velocity, as shown, for example, by lines 504 and 506. It is also contemplated that the variation in the flow rate of hydraulic fluid with the amount of pressure drop, current, voltage, or angular velocity may be discontinuous, as shown in lines 502, 504, 506, but rather take discrete values ​​or piecewise continuous values. Various other mathematical relationships between the amount of pressure drop, current, voltage, or angular velocity readings and the flow rate are also contemplated. Data represented by lines 502, 504, 506, or other data relating flow rate to quantities of voltage drop, current, voltage, or angular velocity, can be stored in a memory device 72 associated with the controller 70. In some embodiments, the relationship between flow rate and quantities of voltage drop, current, voltage, or angular velocity can be in the form of a lookup table, which can be stored in the memory device 72. Although Figure 5A two-dimensional relationship between the quantity of pressure drop, current, voltage, or angular velocity of the hydraulic fluid and its flow rate is shown, but it is envisioned that the flow rate may additionally or alternatively depend on other parameters, such as temperature, pump pressure, hydraulic oil properties (e.g., density, viscosity, etc.), and / or other operating parameters of the milling machine 10 or 20. It is envisioned that the relationship between the flow rate of the hydraulic fluid and the quantity of pressure drop, current, voltage, or angular velocity and / or other machine parameters may be stored in memory device 72 in the form of graphs, diagrams, mathematical functions, algorithms, and / or lookup tables.

[0056] Hydraulic circuit 140 may include one or more temperature sensors 184, which may be configured to determine the temperature of hydraulic fluid in tank 170 or hydraulic fluid flowing through flow sensors 178, 180, or 182. Temperature sensors 184 may be disposed in tank 170 or in one or more tank fluid conduits 172, 174, or 176. Controller 70 may be configured to correct the flow rate of hydraulic fluid based on temperature. For example, at higher temperatures, the viscosity of the hydraulic fluid may be lower, and it may have a lower density compared to lower temperatures. The viscosity and density of the hydraulic fluid can affect the flow rate of the hydraulic fluid through flow sensors 178, 180, or 182. Controller 70 may utilize correlations, graphs, tables, mathematical relationships, algorithms, etc., relating the temperature of the hydraulic fluid to its flow rate to correct the flow rate determined based on pressure drop, current, voltage, or angular velocity.

[0057] The controller 70 can also be configured to determine the amount (e.g., mass or volume) of hydraulic fluid flowing through one or more flow sensors 178, 180, or 182 into or out of the front chambers 96, 148, or 158 based on the flow rate and the amount of time associated with the flow rate. The controller 70 may employ an internal timer to determine the amount of time associated with the flow rate. For example, the controller 70 may monitor one or more input devices 66 configured to raise or lower the frame 22. The controller 70 may employ a timer to determine the time period during which an operator can activate one or more input devices 66 to raise or lower the frame 22 relative to the ground surface 64. The controller 70 may also determine the flow rate of hydraulic fluid entering or leaving the actuators 88, 134, 136 based on the determined flow rate and the time associated with the determined flow rate. Furthermore, based on the geometry of the corresponding cylinders 90, 142, or 152, the controller 70 can determine the extension or retraction (i.e., the amount of displacement or linear movement) of rods 94, 146, or 156 of pistons 92, 144, and 154, respectively, and can further determine the height of frame 22 relative to ground surface 64 based on the determined extension or retraction of rods 94, 146, and / or 156. Therefore, by determining the flow rate and / or flow volume of hydraulic fluid through each of flow sensors 178, 180, and 182, the controller 70 can determine the height of frame 22 relative to tracks 28, 30, and 32, respectively. In some exemplary embodiments, the controller 70 may also be configured to display the determined height of frame 22 on display 68.

[0058] The controller 70 can also be configured to correct for height determined based on the flow rate or volume of hydraulic fluid via flow sensors 178, 180, and 182. For example, consider a scenario where an operator uses one or more input devices 66 to raise the frame 22 relative to the ground surface 64. The controller 70 can receive from the proximity sensor 104 a signal indicating that the edge 86 of the second segment 82 is adjacent to the proximity sensor 104. The controller 70 can also determine, at that location, the height "H" of the frame 22 relative to the ground surface 64 adjacent to the track 28 based on one or more of pressure drop, flow rate, time associated with the flow rate, angular velocity, current or voltage associated with the flow sensor 178. 测量 "Settings. As discussed above, when the edge 86 of the second segment 82 is set to be adjacent to the proximity sensor 104, the controller 70 can determine the actual height of the frame 22 relative to the ground surface 64." 实际 The height is defined as "h1 + H2". The controller 70 can compare the measured height with the actual height and determine the height error "ΔH = H". 实际 -H 测量 The controller 70 can use height error ΔH correction to measure height H. 测量In some exemplary embodiments, the controller 70 may be configured to determine an error ΔH whenever it receives a signal from one or more proximity sensors 104, 106, 108, 110, 124, or 126. Alternatively, the controller 70 may be configured to determine the error at predetermined time intervals or based on input received from an operator via one or more input devices 66.

[0059] It is also envisioned that controller 70 can be configured to determine the error in the flow rate of the hydraulic fluid based on a determined height error ΔH. Controller 70 can modify one or more graphs, figures, mathematical functions, algorithms, or lookup tables that correlate the amount of pressure drop, current, voltage, or angular velocity with the flow rate of the hydraulic fluid based on the determined flow error. Controller 70 can use the flow rate error to update one or more graphs, figures, mathematical functions, algorithms, or lookup tables related to pressure drop, current, voltage, or angular velocity and the flow rate of the hydraulic fluid. Controller 70 can store one or more of the updated graphs, figures, mathematical functions, algorithms, or lookup tables in memory device 72. In some exemplary embodiments, controller 70 can execute machine learning algorithms to determine changes in the height error or flow rate error, and can update the relationship between pressure drop, current, voltage, or angular velocity and flow rate in memory device 72 based on the machine learning algorithm.

[0060] Figure 4B A schematic diagram of another exemplary hydraulic circuit 190 for a milling machine 10 or 20 is shown. Figure 4B As shown, the hydraulic circuit 190 can be applied to a milling machine 10 or 20, which includes two front tracks (e.g., left front track 28 and right front track 30) and two rear tracks (e.g., left rear track 32 and right rear track 34). Figure 4B Many features of the hydraulic circuit 190 shown are similar to Figure 4A The features of hydraulic circuit 140. In the following disclosure, only the features of hydraulic circuit 190, which differ from those of hydraulic circuit 140, will be discussed in detail. As mentioned above regarding Figure 4A The left front track 28 can be connected to the frame 22 via the outrigger post 36 (see...). Figure 1 The right front track can be connected to the frame 22 via outrigger column 38 (see...). Figure 1 The left rear track 32 can be connected to the frame 22 via the outrigger post 40 (see...). Figure 1 Furthermore, the right rear track 34 can be connected to the frame 22 via the outrigger post 42 (see...). Figure 1 However, as Figure 4B As shown, the left rear track 32 can be positioned adjacent to one side of the frame 22, and the right rear track 34 can be positioned adjacent to the opposite side of the frame 22 and is laterally spaced from the left rear track 32 along the width W of the frame 22.

[0061] The left front track 28 can be connected to the frame 22 via the left front actuator 88, the right front track 30 can be connected to the frame 22 via the right front actuator 134, the left rear track 32 can be connected to the frame 22 via the left rear actuator 136, and the right rear track 34 can be connected to the frame 22 via the right rear actuator 192. Actuators 88, 134, 136, and 192 can be located inside or outside the outrigger posts 36, 38, 40, and 42, respectively. The left front actuator 88, right front actuator 134, and left rear actuator 136 can have structural and functional characteristics similar to those described above. The right rear actuator 192 can include a cylinder 194, a piston 196, and a rod 198. The piston 196 can be slidably disposed within the cylinder 194, and the cylinder 194 can be divided into a front end chamber 200 and a rod end chamber 202. That is, the piston 196 can be configured to slide within the cylinder 194. One or both of the front end chamber 200 and the rod end chamber 202 may be configured to retain and receive hydraulic fluid. A cylinder 194 may be connected to the frame 22 adjacent to the front end chamber 200. A rod 198 may be connected at one end to a piston 196 and at the opposite end to a track 34.

[0062] For example Figure 4B As shown, the left rear actuator 136 and the right rear actuator 192 can be connected to each other to form a fully floating shaft. For example, the front chamber 158 of the left rear actuator 136 can be connected to the front chamber 200 of the right rear actuator 192 via a front fluid conduit 204. Similarly, the rod end chamber 160 of the left rear actuator 136 can be connected to the rod end chamber 202 of the right rear actuator 192 via a rod end fluid conduit 206. A tank fluid conduit 176 can connect a tank 170 to the front fluid conduit 204. Therefore, hydraulic fluid can flow from the tank 170 to the two front chambers 158 and 200 of the left rear actuator 136 and the right rear actuator 192. A flow sensor 182 can be disposed in the tank fluid conduit 176. Although... Figure 4B A left rear actuator 136 and a right rear actuator 192 connected via a front end fluid conduit 204 and a rod end fluid conduit 206 are shown, but it is contemplated that in some exemplary embodiments, the left rear actuator 136 and the right rear actuator 192 may not be connected to each other. In this configuration, the front end chambers 158 and 200 of the left rear actuator 136 and the right rear actuator 192 may be individually connected to the tank 170 via separate fluid conduits. Each of these fluid conduits may include its own flow sensor, the structure and functional characteristics of which may be similar to those of flow sensors 178, 180, and 182. Flow sensors 178, 180, and 182, individually or in combination with controller 70, may constitute exemplary fluid flow-based height sensors.

[0063] Figure 6Another exemplary embodiment of a fluid flow-based height sensor is shown. In the following description, the fluid flow-based height sensor is described with reference to a flow sensor 178, an actuator 88, and a track 28. Figure 6 Many components of the actuator 88 and track 28 are similar to those previously discussed. Figure 3A and 3B The descriptions of those elements, and the common elements thereof, will not be repeated here. Furthermore, it should be understood that flow sensors 180 and 182 may have the same... Figure 6 The flow sensor 178 of the exemplary embodiment has similar structural and functional characteristics to the flow sensor 178.

[0064] like Figure 6 As shown in the exemplary embodiment, the flow sensor 178 may include a cylinder 220 extending from one end (or first end) 222 to an opposite end (or second end) 224. A piston 226 may be slidably disposed within the cylinder 220 and may be configured to slide within the cylinder 220 between the first end 222 and the second end 224. The piston 226 may divide the cylinder 220 into a first chamber 228 and a second chamber 230. Both the first chamber 228 and the second chamber 230 may be configured to receive and retain hydraulic fluid. A reservoir fluid conduit 172 may connect the reservoir 170 to the actuator 88. Figure 6 As shown, the reservoir fluid conduit 172 may include fluid conduit 232 and fluid conduit 234. Fluid conduit 232 can connect the reservoir 170 to the second chamber 230 of the cylinder 220. Fluid conduit 234 can connect the first chamber 228 of the cylinder 220 to the front end chamber 96 of the actuator 88. As discussed above, it is contemplated that in some exemplary embodiments, a flow sensor 178 or a sensor similar to flow sensor 178 may additionally or alternatively be connected to the rod end chamber 98 of the actuator 88.

[0065] from Figure 6 It is evident that when hydraulic fluid flows from tank 170 to second chamber 230 via fluid conduit 232, the hydraulic fluid can fill second chamber 230, allowing piston 226 to slide slidably in the direction from second end 224 toward first end 222. This, in turn, reduces the volume of first chamber 228, forcing hydraulic fluid from first chamber 228 into front chamber 96, which can cause actuator 88 to extend, thereby increasing the height of frame 22 relative to ground surface 64. Similarly, when hydraulic fluid flows from second chamber 230 to tank 170 via fluid conduit 232, hydraulic fluid can be emptied from second chamber 230. Therefore, hydraulic fluid from front chamber 96 can flow into first chamber 228 via fluid conduit 234, causing actuator 88 to retract. This, in turn, reduces the height of frame 22 relative to ground surface 64.

[0066] For example Figure 6As shown, cylinder 220 may include position sensor 240. In such a case... Figure 6 In one exemplary embodiment shown, the position sensor 240 may include a first sensor element 242, which may be attached to or positioned near a first end 222 of the cylinder 220. The position sensor 240 may also include a second sensor element 244. In one exemplary embodiment, as shown... Figure 6 As shown, the second sensor element can be attached to the piston 226. The position sensor 240 can be configured to determine the distance "Ds" between the first sensor element 242 and the second sensor element 244.

[0067] In one exemplary embodiment, the position sensor 240 may be a wire-line sensor with a cord associated with a first sensor element 242. The end of the cord may be connected to a second sensor element 244. The cord may be wound or unwound on the spool as the piston 226 moves away from or toward the first end 222. The sensor element associated with the position sensor 240 can determine when the piston 226 moves to a new position (e.g., as...). Figure 6 When (shown as dashed lines in the middle), the distance ΔD corresponding to piston 226. S The change in the length of the rope "ΔD" S The change in “”. As described above, the cylinder with a cord sensor is disclosed in U.S. Patent No. 6,234,601, the contents of which are expressly incorporated herein by reference in their entirety.

[0068] In another exemplary embodiment, the first sensor element 242 may be in the form of a rod member attached at one end to a first end 222 of the cylinder 220 and extending within the cylinder 220 from the first end 222 toward a second end 224. The second sensor element 244 may include an opening configured to receive the first sensor element 242, such that the second sensor element 244 is movable relative to the first sensor element 242. Changes in the electrical characteristics (e.g., inductance, capacitance, etc.) between the first sensor element 242 and the second sensor element 244 can be used to determine the movement ΔD of the piston 226 relative to, for example, the first end 222. S .

[0069] In some exemplary embodiments, it is also envisioned that both the first sensor element 242 and the second sensor element 244 may be attached to or positioned near the first end 222. For example, the first sensor element 242 may include a transmitter configured to emit an electromagnetic beam (light, sound, etc.) that may be reflected by the piston 226. The reflected beam may be received by the second sensor element 244, which may include a receiver. Movement ΔD S This can be determined by the position sensor 240 based on the attenuation or change of the reflected beam. For example, based on the distance D of the piston 226 from the first end 222. SThe reflected beam can have different amplitudes, frequencies, power, etc., and some or all of these can be used by the position sensor 240 to determine the movement ΔD of the piston 226 relative to the first end 222. S .

[0070] The controller 70 can be configured to be based on a determined movement ΔD of the piston 226. S To determine the flow rate of hydraulic fluid in the fluid conduit 172 of the storage tank. For example, based on the geometry of piston 226 and / or cylinder 220, the cross-sectional area "A" of piston 226 and / or cylinder 220 can be determined. S The controller 70 can be based on the piston 226 moving a certain distance ΔD. S The flow rate of the hydraulic fluid is determined by the volume of hydraulic fluid displaced by piston 226. Therefore, for example, controller 70 can determine the flow rate of the hydraulic fluid as "A". S xΔD S However, it is conceivable that the controller 70 could use other mathematical functions, correlations, algorithms, or lookup tables based on the determined movement distance ΔD of the piston 226. S To determine the flow rate of hydraulic fluid in fluid conduit 172.

[0071] The controller 70 can also be configured to determine the distance D by which the actuator 88 can extend or retract due to the flow of hydraulic fluid. H For example, based on the geometry of piston 92 and / or cylinder 90, the cross-sectional area "A" of piston 92 and / or cylinder 90 can be determined. A It should be understood that the flow rate of hydraulic fluid in fluid conduit 172 (e.g., A) S xΔD S The volume of hydraulic fluid flowing into or out of the front chamber 96 of the actuator 88 will be approximately equal to the volume of hydraulic fluid flowing into or out of the actuator 88. In one exemplary embodiment, the controller 70 may determine the extension or retraction ΔL of the rod 94 based on the amount of hydraulic fluid flowing in the fluid conduit 172, for example, such as ΔL = (A S xΔD S ) / A A However, it is conceivable that controller 70 can use other mathematical functions, correlations, algorithms, or lookup tables based on the flow rate of hydraulic fluid in fluid conduit 172 (e.g., A). S xΔD S The controller 70 is also configured to determine the extension or retraction ΔL of the rod 94 based on the determined extension or retraction ΔL of the rod 94.

[0072] The size of cylinder 220 and / or piston 226 may be the same as or different from the size of one or more of cylinders 90, 142, 152, 194 and / or one or more of pistons 92, 144, 154, 196. Therefore, region A... S Region A can be associated with one or more of actuators 88, 134, 136, and 192. A Same or different.

[0073] The method for determining the height of the frame 22 of the milling machine 10 or 20 will be described in more detail below.

[0074] Industrial applicability

[0075] The controller 70 and flow sensors 178, 180, 182 disclosed herein can be used on a milling machine 10 or 20 to determine the height of the frame 22 of the milling machine 10 or 20 relative to the ground surface 64. Specifically, the height of the frame 22 can be determined based on the flow parameters (e.g., flow rate or flow volume) of the hydraulic fluid flowing through one or more flow sensors 178, 180, 182 of the milling machine 10 or 20. The determined height can also be corrected using signals from one or more proximity sensors 104, 106, 108, 110, 124, 126.

[0076] Figure 7 An exemplary method 700 is shown for determining the height of the frame 22 of a milling machine 10 or 20 relative to a ground surface 64 using hydraulic circuits 140 or 190. The sequence and arrangement of the steps of method 700 are provided for illustrative purposes. As will be appreciated from this disclosure, method 700 can be modified by, for example, adding, combining, removing, and / or rearranging the steps of method 700. Method 700 can be executed by controller 70. Although method 700 is described below with reference to the front actuator 88 and flow sensor 178, method 700 and its following description and as... Figure 7 The steps shown also apply to the front actuator 134 and flow sensor 180, as well as one or more of the rear actuators 136, 192 and flow sensor 182.

[0077] Method 700 may include the step of raising or lowering frame 22 relative to ground surface 64 (step 702). An operator may perform actions such as raising the frame to a maintenance height for performing maintenance operations or positioning frame 22 at a specific height and angle relative to ground surface before initiating milling operations. Controller 70 may receive signals from one or more input devices 66 instructing the operator to raise or lower frame 22 of milling machine 10 or 20. Controller 70 may cause one or more pumps associated with milling machine 10 or 20 to pump hydraulic fluid from tank 170 into or out of one or more of front chambers 96, 148, 158 and / or 200 via one or more tank fluid conduits 172, 174, 176 to increase or decrease the height of frame 22 adjacent to one or more of tracks 28, 30, 32 and / or 34. For example, controller 70 may control one or more control valves associated with milling machine 10 or 20 to allow hydraulic fluid to flow through flow sensor 178 and via reservoir fluid conduit 172. When frame 22 is raised or lowered, controller 70 may receive signals indicating, for example, whether the edge 84 or target 128 of the first segment 80 is located near one of proximity sensors 108 or 110; whether the edge 86 or target 116 is located near one of proximity sensors 104 or 106; or whether the edge 86, track end 102, or target 128 is located near one of proximity sensors 124 or 126. As discussed above, based on these signals and the known geometry of milling machines 10 and 20, the controller can determine the initial height "H" of frame 22 relative to ground surface 64. 初始 ".

[0078] Method 700 may include the step of determining the flow rate of hydraulic fluid through flow sensor 178 (step 704). Controller 70 may receive one or more signals from flow sensor 178 indicating pressure drop, current, voltage, or angular velocity associated with flow sensor 178. Controller 70 may use data that correlates pressure drop, current, voltage, or angular velocity with flow rate to determine the flow rate through flow sensor 178. For example, controller 70 may use data stored in memory device 72 representing graphs, charts, mathematical functions, algorithms, lookup tables, etc., to determine the flow rate corresponding to the pressure drop, current, voltage, or angular velocity associated with flow sensor 178. In some exemplary embodiments, controller 70 may determine the change in flow rate over time based on the relationship between pressure drop, current, voltage, or angular velocity and flow rate.

[0079] Method 700 may include the step of determining a time period associated with the flow rate of hydraulic fluid passing through flow sensor 178 (step 706). Controller 70 may determine the time period during which hydraulic fluid flows through flow sensor 178. Controller 70 may do so using a timer associated with controller 70. In some exemplary embodiments, controller 70 may continuously monitor the flow rate of hydraulic fluid flowing through flow sensor 178 over a period of time. Controller 70 may store the change in flow rate over time in memory device 72.

[0080] Method 700 may include the step of determining the flow rate of hydraulic fluid in the reservoir fluid conduit 172 (step 708). Controller 70 may determine the flow rate of hydraulic fluid entering or leaving the front chamber 96 based, for example, the flow rate and time period determined in steps 704 and 706. In some exemplary embodiments, controller 70 may employ integration, summation, or other mathematical operations to determine the flow rate of hydraulic fluid based, for example, the change in flow rate over time determined in step 708.

[0081] Method 700 may include the step of determining the height of frame 22 relative to ground surface 64 (step 710). Controller 70 may determine the extension (or retraction) of rod 94 (or actuator 88) based, for example, the hydraulic fluid flow rate determined in steps 704-708. For example, based on the known geometry of cylinder 90 and piston 92, controller 70 may determine the cross-sectional area "A" of cylinder 90 or piston 92. A The controller 70 can then, for example, divide the determined hydraulic fluid flow rate by the cross-sectional area A. A The controller 70 determines the extension (or retraction) "ΔL" of the lever 94 (or actuator 88). It is conceivable that the controller 70 can perform other mathematical operations or employ other algorithms to determine the extension (or retraction) ΔL of the lever 94. In one exemplary embodiment, the controller 70 can be based on an initial height H. 初始 The extension (or retraction) ΔL of rod 94 determines the measured height H of frame 22 relative to ground surface 64. 测量 The controller 70 can also be configured to cause a determined height H of the display frame 22 of the display 68. 测量 .

[0082] Method 700 may include a step of determining a height error (step 712). Controller 70 may be configured to determine the height error when it receives a signal from one or more of proximity sensors 104, 106, 108, 110, 124, or 126. As discussed above, when controller 70 receives a signal from one or more of proximity sensors 104, 106, 108, 110, 124, or 126, controller 70 may be configured to determine the actual height H based on the known geometry of machine 10 or 20 and the known positions of proximity sensors 104, 106, 108, 110, 124, or 126 relative to frame 22 or ground surface 64. 实际 For example, when edge 86 or target 116 can be located near proximity sensor 106, controller 70 can receive a signal from proximity sensor 106. This is based on, for example, the position of proximity sensor 106 at a distance h1+h2 relative to frame 22 and the position of edge 86 at a distance H2 relative to ground surface 64 (see...). Figure 3A The controller 70 can display the actual height H. 实际 The height error ΔH is determined to be equal to the sum of the two distances, i.e., h1 + h2 + H2. The controller 70 can then determine the actual height H as the height error ΔH. 实际 With the measured height H 测量 The difference between them.

[0083] In some exemplary embodiments, controller 70 may use a timer to monitor the timing of triggering the paired proximity sensors to determine a height error. For example, when actuator 88 extends or retracts, controller 70 may receive a signal from proximity sensor 104 at time “t1” indicating that the edge 86 of the second segment 82 is positioned adjacent to proximity sensor 104. Controller 70 may also receive a signal from proximity sensor 106 at time “t2” indicating that the edge 86 of the second segment 82 is positioned adjacent to proximity sensor 106. Controller 70 may determine the extension or retraction ΔL of rod 94 during the time period between time t1 and t2 by determining the flow rate of hydraulic fluid flowing through flow sensor 178 during the time period from t1 to t2. Controller 70 may determine the flow rate using the process described above, for example, with respect to step 704. Controller 70 may also determine the amount of hydraulic fluid flowing into front chamber 96 during the time period between time t1 and t2 based on the determined flow rate and the time period between time t1 and t2. The controller can compare the extension ΔL of rod 94 with the known distance h2 between proximity sensors 104 and 106 to determine the height error ΔH. For example, controller 70 can determine the height error as h2 – ΔL.

[0084] Method 700 may include a step of correcting the height of frame 22 (step 714). Controller 70 may use, for example, the height error ΔH determined in step 712 to correct, for example, the measured height H of frame 22 determined in step 710. 测量 For example, controller 70 can add the height error ΔH to the measured height H. 测量 The controller 70 can also store the value of the height error ΔH in the memory device 72, and can use the stored value of the height error ΔH to correct subsequently measured heights. The controller 70 can also be configured to cause the display 68 to display the corrected height. The controller 70 can repeat the determination of the height error ΔH as it receives signals from one or more proximity sensors 104, 106, 108, 110, 124, or 126. Alternatively, the controller 70 can determine the height error ΔH periodically or based on input received from the operator.

[0085] Figure 8 It shows the use of Figure 6 An exemplary method 800 for determining the height of the frame 22 of a milling machine 10 or 20 relative to the ground surface 64 using a piston cylinder flow sensor 178. The sequence and arrangement of the steps of method 800 are provided for illustrative purposes. As will be appreciated from this disclosure, method 800 can be modified by, for example, adding, combining, removing, and / or rearranging the steps of method 800. Method 800 can be executed by controller 70. Although method 800 is described below with reference to the front actuator 88 and flow sensor 178, method 800 and its following description and as... Figure 7 The steps shown also apply to the front actuator 134 and flow sensor 180, as well as one or more of the rear actuators 136, 192 and flow sensor 182.

[0086] Method 800 may include the step of raising or lowering frame 22 relative to ground surface 64 (step 802). Step 802 may include a process similar to that discussed above with respect to step 702 of method 700, for example.

[0087] Method 800 may include determining the displacement ΔD of the piston in the flow sensor 178. SStep (step 804). Controller 70 may receive one or more signals from position sensor 240 associated with flow sensor 178. In some exemplary embodiments, controller 70 may receive signals indicating changes in the length or inductance or capacitance of a cord, the signals indicating changes in the distance between the first sensor element 242 and the second sensor element 244 of position sensor 240. In other exemplary embodiments, controller 70 may receive signals indicating changes in the amplitude, frequency, or power of an electromagnetic beam emitted by the first sensor element 242 and received by the second sensor element 244. The received signals may indicate changes in the distance between piston 226 and the first end 222 of cylinder 220. Controller 70 may rely on correlations, mathematical functions, algorithms, lookup tables, etc., stored in memory device 72 to determine the displacement ΔD of piston 226 based on signals received from position sensor 240. S .

[0088] Method 800 may include the step of determining the amount of hydraulic fluid flowing through flow sensor 178 (step 806). Controller 70 may base its decisions on, for example, the displacement ΔD of piston 226 determined in step 804 of method 800. S To determine the flow rate of hydraulic fluid. For example, based on the geometry of piston 226 and / or cylinder 220, controller 70 can determine the cross-sectional area "A" of piston 226 and / or cylinder 220. S The controller 70 can be based on the piston 226 moving a certain distance ΔD. S The flow rate of the hydraulic fluid is determined by the volume of hydraulic fluid displaced by piston 226. Therefore, for example, controller 70 can determine the flow rate of the hydraulic fluid as "A". S xΔD S However, it is conceivable that the controller 70 can use other mathematical functions, correlations, algorithms, or lookup tables stored in the memory device 72 to determine the displacement ΔD of the piston 226. S To determine the flow rate of hydraulic fluid flowing through flow sensor 178 and fluid conduit 172.

[0089] Method 800 may include the step of determining the height of frame 22 relative to ground surface 64 (step 808). Step 808 may include a process similar to that discussed above with respect to step 710 of method 700, for example. It is conceivable that method 800 may also include steps similar to steps 710-714, which determine height error and correct the height of frame 22 relative to ground surface 64.

[0090] It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed milling machine and fluid flow-based height sensor. Other embodiments will be apparent to those skilled in the art in light of the specification and practice of the disclosed milling machine and fluid flow-based height sensor. The specification and examples are intended to be illustrative only, and the true scope is indicated by the following claims and their equivalents.

Claims

1. A milling machine, comprising: frame; A milling drum, which is attached to the frame; Multiple ground-jointing tracks, the multiple ground-jointing tracks being configured to support the frame and propel the milling machine in a forward or backward direction; Storage tank, the storage tank being configured to store hydraulic fluid; The frame is connected to at least one actuator of the track, the at least one actuator being configured to adjust the height of the frame relative to the ground surface; A fluid conduit connecting the tank to the at least one actuator; A flow sensor configured to determine flow parameters associated with the flow of hydraulic fluid entering or leaving the at least one actuator; as well as A controller configured to determine the height of the frame relative to the ground surface based on the flow parameters; The milling machine further includes outriggers for connecting the frame to the track, the outriggers comprising: The first segment connected to the frame; A second section that is slidably movable relative to the first section and connected to the track; and The at least one actuator; wherein the at least one actuator comprises: A cylinder, which is connected to the frame and contains the hydraulic fluid; Piston, the piston being slidably disposed within the cylinder; and A rod having a first end connected to the piston and extending from the piston to a second end, the second end being connected to a track in one of the plurality of ground-engaging tracks; the flow parameter is the flow rate of the hydraulic fluid; The milling machine further includes a first proximity sensor positioned on the first section at a first distance from the frame, wherein, The first proximity sensor is configured to generate a first signal when the edge of the second segment is adjacent to the first proximity sensor. The milling machine further includes a second proximity sensor attached to the first segment, the second proximity sensor being spaced a second distance from the first proximity sensor. The second proximity sensor is configured to generate a second signal when the edge of the second segment is adjacent to the location of the second proximity sensor; The controller is further configured to: Receive the first signal and the second signal from the first proximity sensor and the second proximity sensor; Determine the elapsed time between the first signal and the second signal; The flow rate of the hydraulic fluid is determined based on the flow velocity and the elapsed time. Determine the extension of the rod during the elapsed time; The error in the extension of the rod is determined based on the extension of the rod and the second distance; and The flow rate is corrected based on the error.

2. The milling machine according to claim 1, wherein the flow sensor comprises: A cylinder that contains the hydraulic fluid; A piston, which is slidably disposed within the cylinder and configured to divide the cylinder into a first chamber and a second chamber; as well as A position sensor configured to measure the distance between one end of the piston and the cylinder, wherein the fluid conduit includes: A first fluid conduit connects the storage tank to the first chamber; as well as A second fluid conduit connects the second chamber to the at least one actuator, wherein the flow of hydraulic fluid via the first or second fluid conduit causes the extension or retraction of the at least one actuator.

3. The milling machine according to claim 1, wherein The controller is configured as follows: Determine the time period associated with the flow rate; The flow rate of the hydraulic fluid entering or leaving the at least one actuator is determined based on the flow rate and the time period. The extension of the rod is determined based on the determined flow rate; and The height of the frame is determined based on the extension.

4. The milling machine according to claim 1, wherein the flow sensor is a bidirectional flow meter.

5. The milling machine of claim 1, further comprising a temperature sensor configured to determine the temperature of the hydraulic fluid, wherein the controller is configured to adjust flow parameters based on the temperature.

6. The milling machine of claim 1, wherein the flow parameter is the flow rate of the hydraulic fluid, and the controller is configured to: Determine the change in the distance between the piston and one end of the cylinder; and The flow rate of the hydraulic fluid entering or leaving the at least one actuator is determined based on the change in the distance.

7. The milling machine according to claim 1, wherein the sensor is one of a wire sensor, an inductive sensor, a capacitive sensor, or a laser sensor.

8. The milling machine according to claim 1, wherein the sensor comprises: A first sensor portion attached to one end of the cylinder; as well as The second sensor portion is attached to the piston.

9. A milling machine, comprising: frame; A left front track, wherein the left front track is disposed adjacent to the front end of the frame; The right front track is disposed adjacent to the front end and spaced apart from the left front track; At least one rear track, the at least one rear track being disposed adjacent to the rear end of the frame; A left front actuator, the left front actuator being connected to the frame and the left front track; A right front actuator, the right front actuator being connected to the frame and the right front track; A rear actuator, connected to the frame and the at least one rear track, wherein each of the left front actuator, the right front actuator, and the rear actuator is configured to selectively adjust the height of the frame relative to the left front track, the right front track, and the at least one rear track, respectively. A milling drum, which is connected to the frame and disposed between the front end and the rear end; An engine configured to rotate the milling drum and propel the left front track, the right front track, and the at least one rear track in a forward or backward direction; At least one flow sensor, configured to determine flow parameters associated with hydraulic fluid flow entering or leaving at least one of the left front actuator, the right front actuator, and the rear actuator, and A controller configured to determine the height of the frame relative to at least one of the left front track, the right front track, and the at least one rear track based on the flow parameters; The milling machine further includes a left front outrigger column, a right front outrigger column, and a rear outrigger column connecting the frame to the track, each outrigger column comprising: The first segment connected to the frame; A second section that is slidably movable relative to the first section and connected to the track; and The corresponding left front actuator, right front actuator, and rear actuator; wherein each of the actuators includes: A cylinder, which is connected to the frame and contains the hydraulic fluid; Piston, the piston being slidably disposed within the cylinder; and A rod having a first end connected to the piston and extending from the piston to a second end, the second end being connected to a track in a plurality of ground-engaging tracks; the flow parameter is the flow rate of the hydraulic fluid; For each outrigger column, the milling machine further includes a first proximity sensor positioned on the first section at a first distance from the frame, wherein, The first proximity sensor is configured to generate a first signal when the edge of the second segment is adjacent to the first proximity sensor. The milling machine further includes a second proximity sensor attached to the first segment, the second proximity sensor being spaced a second distance from the first proximity sensor. The second proximity sensor is configured to generate a second signal when the edge of the second segment is adjacent to the location of the second proximity sensor; The controller is further configured to: Receive the first signal and the second signal from the first proximity sensor and the second proximity sensor; Determine the elapsed time between the first signal and the second signal; The flow rate of the hydraulic fluid is determined based on the flow velocity and the elapsed time. Determine the extension of the rod during the elapsed time; The error in the extension of the rod is determined based on the extension of the rod and the second distance; and The flow rate is corrected based on the error.

10. The milling machine according to claim 9, wherein the at least one flow sensor comprises: A left front flow sensor, the left front flow sensor being configured to determine a first flow parameter associated with a first hydraulic fluid flow entering or leaving the left front actuator; A right front flow sensor, configured to determine a second flow parameter associated with a second hydraulic fluid flow entering or leaving the right front actuator; and A rear flow sensor, configured to determine a third flow parameter associated with a third hydraulic fluid flow entering or leaving the rear actuator.

11. The milling machine according to claim 9, wherein the flow sensor comprises: A cylinder that contains the hydraulic fluid; A piston, which is slidably disposed within the cylinder and configured to divide the cylinder into a first chamber and a second chamber; as well as A position sensor configured to measure the distance between one end of the piston and the cylinder, wherein the fluid conduit includes: A first fluid conduit connects the storage tank to the first chamber; as well as A second fluid conduit connects the second chamber to the at least one actuator, wherein the flow of hydraulic fluid via the first or second fluid conduit causes the extension or retraction of the at least one actuator.

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