System and method for operating milling machines

Abstract

A system for operating a milling machine 102 is described. The system includes one or more sensors 168 configured to detect an extension of one or more legs 138 of the milling machine correspondingly

Description

Technical Field

[0001] The present disclosure relates to a milling machine, such as a cold planer. More particularly, the present disclosure relates to a system and method for controlling a travel speed of the milling machine based on a height of legs that support traction devices of the milling machine. Background

[0002] Milling machines, such as cold planers, are used for performing various earth-altering operations, such as removal of material from a work surface, and mixing or reclaiming material from the work surface. The milling machine generally includes multiple traction devices for facilitating machine movement over the work surface. Each traction device is commonly coupled to a frame of the milling machine by a corresponding leg that is actuated (e.g., hydraulically) to raise or lower the frame with reference to an underlying work surface. With an increase in a height of the milling machine, which may be applicable during machine travel, etc., the amount of work surface unevenness that can be accommodated by the legs or the traction devices during the travel is reduced.

[0003] United States Patent No.: 9,267,446 B2 relates to an engine speed management control system for machines such as cold planers to regulate the idle engine speed as components of the machine are operated to perform functions while the engine is idling. Summary of the Invention

[0004] In one aspect, the disclosure relates to a system for operating a milling machine. The system includes one or more sensors configured to detect an extension of one or more legs of the milling machine correspondingly with respect to one or more traction devices of the milling machine. The one or more legs extend with respect to the one or more traction devices to raise or lower a frame of the milling machine with respect to the one or more traction devices. The system further includes a controller configured to determine a travel speed of the milling machine and compute an extension height value of the one or more legs based on the extension of the one or more legs. The controller is further configured to determine a condition to limit the travel speed of the milling machine up to a maximum travel speed when the extension height value exceeds a height value threshold.

[0005] In another aspect, the disclosure is directed to a method for operating a milling machine. The method includes detecting, via one or more sensors, an extension of one or more legs of the milling machine correspondingly with respect to one or more traction devices of the milling machine. The one or more legs extend with respect to the one or more traction devices to raise or lower a frame of the milling machine with respect to the one or more traction devices. The method further includes determining, by a controller, a travel speed of the milling machine and computing, by the controller, an extension height value of the one or more legs based on the extension of the one or more legs. Further, the method includes determining, by the controller, a condition to limit the travel speed of the milling machine up to a maximum travel speed when the extension height value exceeds a height value threshold.

[0006] In yet another aspect, the disclosure relates to a milling machine. The milling machine includes a frame, a milling chamber supported by the frame, one or more traction devices to provide tractive force to the milling machine, and one or more legs coupled to the frame and the one or more traction devices. The one or more legs are extendable with respect to the one or more traction devices to raise or lower the frame of the milling machine with respect to the one or more traction devices. The milling machine further includes a system for operating the milling machine. The system includes one or more sensors configured to detect an extension of the one or more legs of the milling machine correspondingly with respect to the one or more traction devices of the milling machine and a controller configured to determine a travel speed of the milling machine, compute an extension height value of the one or more legs based on the extension of the one or more legs, and determine a condition to limit the travel speed of the milling machine up to a maximum travel speed when the extension height value exceeds a height value threshold. Brief Description of the Drawings

[0007] FIG. 1 illustrates an exemplary work machine, in accordance with one or more aspects of the present disclosure;

[0008] FIG. 2 illustrates a cross-sectional view of a leg of the work machine of FIG. 1, in accordance with one or more aspects of the present disclosure;

[0009] FIG. 3 illustrates another cross-sectional view of the leg of the work machine of FIG. 1, in accordance with one or more aspects of the present disclosure;

[0010] FIG. 4 is a schematic view of an exemplary system for operating the work machine of FIG. 1, in accordance with one or more aspects of the present disclosure; and

[0011] FIG. 5 is a flowchart illustrating a method for operating the work machine of FIG. 1, in accordance with one or more aspects of the present disclosure. Detailed Description

[0012] Reference will now be made in detail to specific aspects or features, examples of which are illustrated in the accompanying drawings. Wherever possible, corresponding, or similar reference numbers will be used throughout the drawings to refer to the same or corresponding parts. Generally, corresponding reference numbers may be used throughout the drawings to refer to the same or corresponding parts, e.g., 1, F, and 1" could refer to one or more comparable components used in the same and / or different depicted embodiments.

[0013] Referring to FIG. 1, an exemplary work machine 100 is shown and described. The work machine 100 may include a milling machine 102, such as a roadway / pavement profiler, a roadway planer, a cold planer, and / or the like. The work machine 100 may be used to perform a milling operation to modify a ground surface 104. For example, the milling operation may mean or include one or more of scarifying, removing, mixing, and / or reclaiming material, from the ground surface 104. The ground surface 104 may be a worn-out surface formed from one or more of asphalt, bitumen, concrete, and / or other road surface materials. One or more layers of the ground surface 104 may be milled and removed by way of the milling operation for the laying of a new ground surface.

[0014] As shown in FIG. 1, the work machine 100 may define a forward end 106 and a rearward end 108 opposite to the forward end 106. The forward end 106 and the rearward end 108 may be defined in relation to an exemplary direction of travel T of the work machine 100, with said direction of travel T being defined exemplarily from the rearward end 108 towards the forward end 106. Further, terms such as ‘left’ and ‘right’, as used in the present disclosure, may be understood as the work machine 100 is viewed from the rearward end 108 towards the forward end 106. The work machine 100 may include a first side 110 and a second side (not shown) opposite to the first side 110 of the work machine 100. The first side 110 may correspond to the right side of the work machine 100 and the second side may correspond to the left side of the work machine 100 when viewing the work machine 100 from the rearward end 108 towards the forward end 106.

[0015] The work machine 100 may include a frame 112 and an operator station 114 supported on the frame 112. The operator station 114 may house any number of output devices 184 (shown in FIG. 4) and control devices (e.g., a throttle control, a braking control, a steering device 116, etc.) that an operator may use to facilitate an operator in operating the work machine 100. In some embodiments, the output device 184 (shown in FIG. 4) may include buttons, screens, lights, switches, and any other output device that can provide one or more of auditory, visual, or haptic feedback to the operator. More specifically, the output device 184 (shown in FIG. 4) may include one or more of a screen or touchscreen for visual feedback, a speaker or the like for auditory feedback, and vibrating components for haptic feedback.

[0016] The work machine 100 may include a milling chamber 118 supported by the frame 112 and configured to facilitate the milling operation. During a milling operation, the ground surface 104 may be milled by the milling chamber 118 as the work machine 100 moves over the ground surface 104. The milling operation facilitates disintegration of one or more layers of the ground surface 104 to result in milled materials and thus a milled ground surface. The milling chamber 118 may include a milling drum 120. The milling drum 120 may be applied to engage and mill the ground surface 104 during the milling operations so as to obtain the milled materials and thus the milled ground surface. The milling drum 120 may grind and scrape off a top of the ground surface 104 or one or more layers (e.g., top layers) of the ground surface 104 that the milling drum 120 may come in contact with. In so doing, such layers of the ground surface 104 may break into rubble, dust, and debris, and may result in the formation of the milled materials which may be transferred to a conveyor system 122 so as to clear the milled ground surface of the milled materials. The conveyor system 122 may in turn convey the milled materials into a haul machine, such as a dump truck, (not shown) that may move ahead of the work machine 100 during the milling operation.

[0017] The work machine 100 may further include a power source 128. The power source 128 may by supported on the frame 112 and may be configured to provide mechanical and / or electrical power to the work machine 100. The power source 128 may include one or more of an internal combustion engine, an electric generator, a fluid pump, a fuel cell, a battery, or any other suitable device configured to power the work machine 100. In one example, the power source 128 may be configured to propel the work machine 100 on the ground surface 104, provide power to various components, such as the milling drum 120, the conveyor system 122, and one or more other components (e.g., pumps, fans, motors, generators, belt drives, transmission devices, etc.) associated with the work machine 100.

[0018] The work machine 100 may include one or more traction devices 132 to provide tractive force to the work machine 100. Exemplarily, the work machine 100 may include four traction devices 132, although lesser or greater numbers of traction devices 132 may be contemplated. FIG. 1 shows only two traction devices 132, for example, a rear traction device 132' disposed adjacent to the rearward end 108 and a forward traction device 132" disposed adjacent to the forward end 106 on the first side 110 of the work machine 100, with the other traction devices being respectively (and exemplarily) hidden behind the forward traction device 132" and the rear traction device 132' in the view of FIG. 1 and being also exemplarily disposed on the second side of the work machine 100. The traction devices 132 may include tracks, wheels, or a combination thereof. The traction devices 132 may be rotatably supported on the frame 112 and operatively connected to one or more motors (not shown) to drive the traction devices 132 to propel the work machine 100 on the ground surface 104. The motors (not shown) may be configured to modify a speed of the work machine 100 by modifying a speed of rotation of the one or more traction devices 132. The motors (not shown) may be powered by the power source 128 and operably coupled to the power source 128 via electrical wires, fluid conduits, or any other suitable connection.

[0019] The work machine 100 may further include one or more vertically adjustable legs 138 coupled to the frame 112 and the traction devices 132. For example, a rearward leg 138' is coupled between the frame 112 and the rear traction device 132' disposed on the first side 110 of the work machine 100. Similarly, a forward leg 138" is coupled between the frame 112 and the forward traction device 132" disposed on the first side 110 of the work machine 100. Although not shown in FIG. 1, the other rear traction device and the other forward traction device disposed on the second side of the work machine 100 may also be coupled to the frame 112 via another rearward leg 138' and another forward leg 138", respectively. Each leg 138 is extendable and retractable with respect to the corresponding traction device 132 to in turn raise or lower the frame 112 of the work machine 100 with respect to the corresponding traction device 132. The legs 138 may raise or lower individually or collectively. It will be understood that raising or lowering the frame 112 with respect to the traction devices 132 may also adjust a height of the frame 112 relative to the ground surface 104 on which the traction devices 132 may be supported.

[0020] FIG. 2 illustrates an exemplary cross-sectional view of a leg 138, for example, the rearward leg 138' of the work machine 100, in accordance with an embodiment. Although FIG. 2 describes an arrangement and operation of the rearward leg 138' of the work machine 100, it would be appreciated that the arrangement and operation described with reference to FIG. 2 may be applicable to all other legs 138 of the work machine 100. As shown in FIGs. 1 and 2, the rearward leg 138' may include a leg column 140 that is attached to the rear traction device 132' via a yoke 160 and extends towards the frame 112. The leg column 140 may be a hollow cylindrical tube. It is contemplated, however, that the leg column 140 may have other non-cylindrical shape. The leg column 140 may be extendable and retractable with respect to the frame 112 of the work machine 100.

[0021] An actuator 142 may be disposed within the leg column 140 and is operable to extend the rearward leg 138' with respect to the rear traction device 132'. The actuator 142 may connect the frame 112 with the rear traction device 132' via the yoke 160. The actuator 142 may include a cylinder 144 and an extension rod 148 slidably disposed within the cylinder 144. The cylinder 144 may extend from a frame end 150 connected to the frame 112 to a rod end 162 which may be disposed between the frame 112 and the yoke 160. The extension rod 148 may be slidably disposed within the cylinder 144 and may be configured to slide within the cylinder 144 between the frame end 150 and the rod end 162. The extension rod 148 may be connected to the yoke 160, which in turn may be connected to the rear traction device 132'.

[0022] The actuator 142 may be a hydraulic actuator that is configured to receive and hold hydraulic fluid. The movement of hydraulic fluid in the actuator 142 may cause the extension rod 148 of the actuator 142 to slidably move within the cylinder 144 to increase or decrease a length of the actuator 142, thereby increasing or decreasing the height of the frame 112 with respect to the traction devices 132 of the work machine 100. For example, filing the hydraulic fluid in the actuator 142 (e.g., in its head end chamber) may cause the extension rod 148 to move from the frame end 150 towards the rod end 162, thereby increasing the height of the frame 112 with respect to the traction devices 132 of the work machine 100. Conversely, filing the hydraulic fluid in the actuator 142 (e.g., in its rod end chamber) (and parallely emptying the hydraulic fluid from the actuator 142) may cause the extension rod 148 to move from the rod end 162 towards the frame end 150, thereby decreasing the height of the frame 112 with respect to the traction devices 132 of the work machine 100.

[0023] In accordance with an embodiment, the rearward leg 138' further includes one or more sensors 164 configured to detect an extension of the rearward leg 138' of the work machine 100 with respect to the rear traction device 132' of the work machine 100. In an embodiment, as shown in FIG. 2, the sensor 164 may include a proximity switch 164' configured to detect the extension by sensing a linear displacement of the leg column 140 associated with the rearward leg 138' with respect to the frame 112 of the work machine 100 and convert the sensed displacement into a first electrical signal. As shown in FIG. 2, the proximity switch 164' may be installed on the leg column 140 of the rearward leg 138'. It would be appreciated that the proximity switch 164' may be disposed at any other location on the rearward leg 138', such as on, within, or adjacent to the leg column 140 and / or the frame 112 of the work machine 100, to sense the displacement of the leg column 140 with respect to the frame 112.

[0024] In another embodiment, as shown in FIG. 3, the sensor 164 may include a position sensor 164" disposed within the cylinder 144 of the rearward leg 138' of the work machine 100. The position sensor 164" is configured to detect the extension by sensing a linear displacement of the extension rod 148 with respect to the cylinder 144 of the actuator 142 and convert the sensed displacement into a second electrical signal. Although the position sensor 164" is shown to be disposed within the cylinder 144, it would be appreciated that the position sensor 164" may be disposed at any other location on the rearward leg 138', such as on, within, or adjacent to the cylinder 144 and / or the extension rod 148, to sense the displacement of the extension rod 148 with respect to the cylinder 144. In an exemplary embodiment, the position sensor 164" may include a linear displacement transducer (LDT) or any other sensor configured to detect the displacement of the extension rod 148 with respect to the cylinder 144.

[0025] Although, not shown, the rearward leg 138' may include one or both of the proximity switch 164' and the position sensor 164" to detect the extension of the rearward leg 138' with respect to the rear traction device 132' of the work machine 100. Further, it would be appreciated that various other means to obtain the detect the extension of the rearward leg 138' with respect to the rear traction device 132' of the work machine 100 may be contemplated and those discussed herein are purely exemplary.

[0026] Referring to FIG. 4, details of an exemplary system 180 for operating the work machine 100 are illustrated. In an exemplary embodiment, the system 180 includes the one or more sensors 164, the power source 128, and the output device 184 operatively coupled to a controller 182.

[0027] The controller 182 is configured to determine a travel speed of the work machine 100. In accordance with various embodiments, the travel speed corresponds to the speed of rotation of the one or more traction devices 132 of the work machine 100. The controller 182 is configured to determine the travel speed based on signals received from an electronic control module (ECM), transducers, or one or more sensors configured to detect the speed of rotation of the traction devices 132 of the work machine 100. The one or more sensors may include, but not limited to, a position sensor (e.g., Global Positioning Sensor), an accelerometer, and the like for detecting the speed of rotation of the traction devices 132 of the work machine 100.

[0028] The controller 182 may be further configured to compute an extension height value of the legs 138 based on the extension of the legs 138. To this end, the controller 182 may be configured to receive one or both of the first electrical signal and the second electrical signal from the proximity switch 164' and the position sensor 164", respectively and determine the extension height value of the legs 138 based on the received electrical signal(s). In an exemplary embodiment, the legs 138 are rearward legs 138' of the work machine 100 with respect to the direction of travel T of the work machine 100.

[0029] The controller 182 may be further configured to determine a condition to limit the travel speed of the work machine 100 up to a maximum travel speed when the extension height value exceeds a height value threshold. In accordance with various embodiments, the height value threshold may be any predefined value. For example, the controller 182 may be configured to compare the extension height value with the height value threshold and when the extension height value exceeds the height value threshold, the controller 182 determines the condition to limit the travel speed of the work machine 100 up to the maximum travel speed. In an embodiment, the controller 182 may be configured to restrict the travel speed of the work machine 100 under the maximum travel speed in response to the condition. To this end, the controller 182 is configured to restrict the speed of rotation of the traction devices 132 of the work machine 100 such that the travel speed of the work machine is limited up to the maximum travel speed.

[0030] In some embodiments, the controller 182 may be configured to limit the travel speed of the work machine 100 incrementally with respect to the maximum travel speed as the extension height value increases incrementally above the height value threshold in response to the condition. To this end, the controller 182 may be configured to determine an increase in the extension height value from the height value threshold and limit the speed of rotation of the traction devices 132 of the work machine 100 based on the determined increase. For example, when the extension height value is greater than the height value threshold by ‘XI’, the controller 182 may be configured to limit the speed of rotation of the traction devices 132 to ‘Yl’. However, when the extension height value is greater than the height value threshold by ‘X2’ (where X2>X1), the controller 182 may be configured to further limit the speed of rotation of the traction devices 132 to ‘Y2’ such that Y2<Y1.

[0031] Additionally or alternatively, the controller 182 is configured to provide an alert via the output device 184 in response to the condition to notify the operator of the condition. For example, the alert may include one or more of a visual feedback on the screen or the touchscreen, an auditory feedback on the speaker, and a haptic feedback on the vibrating components of the work machine 100. Industrial Applicability

[0032] During travel of the work machine 100, the work machine 100 (e.g., the milling machine 102) may be required to increase the height of the frame 112 or the milling chamber 118 with respect to the ground surface 104. However, when the height of the frame 112 or the milling chamber 118 is increased with respect to the ground surface 104, the amount of work surface unevenness that can be accommodated by the legs 138 or the traction devices 132 of the work machine 100 during the travel may be reduced. FIG. 5 describes an exemplary method 500 for operating the work machine 100 in such scenarios. The method 500 is discussed by way of a flowchart and is discussed in conjunction with FIGs. 1 to 4, as well.

[0033] The method 500 begins with the one or more sensors 164 detecting the extension of the one or more legs 138 of the work machine 100 correspondingly with respect to the traction devices 132 of the work machine 100, at 502. At 504, the controller 182 determines the travel speed of the work machine 100. The controller 182, at 506, then computes the extension height value of the legs 138 based on the extension of the legs 138. At 508, the controller 182 determines the condition to limit the travel speed of the work machine 100 up to the maximum travel speed when the extension height value exceeds the height value threshold.

[0034] The controller 182 may be one or more processor, a microprocessor, a microcontroller, an electronic control module (ECM), an electronic control unit (ECU), or any other suitable means for determining the condition to limit the travel speed of the work machine 100. The controller 182 may be implemented using one or more controller technologies, such as Application Specific Integrated Circuit (ASIC), Reduced Instruction Set Computing (RISC) technology, Complex Instruction Set Computing (CISC) technology or any other similar technology now known or developed in the future.

[0035] The present disclosure provides a method and system for restricting the travel speed of the work machine 100 under the maximum travel speed when the extension height value of the legs 138 of the work machine 100 exceeds the height value threshold. This ensures that the work machine 100 may relatively smoothly navigate an uneven terrain in scenarios when the amount of work surface unevenness that can be accommodated by the legs 138 or the traction devices 132 becomes limited due to an increase in the height of the work machine 100 (e.g., the frame the work machine 100). This helps prevent the work machine 100, e.g., the legs and traction devices, from any damage and also extends its workable lifespan.

[0036] Unless explicitly excluded, the use of the singular to describe a component, structure, or operation does not exclude the use of plural such components, structures, or operations or their equivalents. The use of the terms “a” and “an” and “the” and “at least one” or the term “one or more,” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context.

[0037] It will be apparent to those skilled in the art that various modifications and variations can be made to the method and / or system of the present disclosure without departing from the scope of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the method and / or system disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalent.

Claims

What is claimed is:

1. A system for operating a milling machine, the system comprising:one or more sensors configured to detect an extension of one or more legs of the milling machine correspondingly with respect to one or more traction devices of the milling machine, wherein the one or more legs extend with respect to the one or more traction devices to raise or lower a frame of the milling machine with respect to the one or more traction devices; anda controller configured to:determine a travel speed of the milling machine;compute an extension height value of the one or more legs based on the extension of the one or more legs; anddetermine a condition to limit the travel speed of the milling machine up to a maximum travel speed when the extension height value exceeds a height value threshold.

2. The system of claim 1, wherein, in response to the condition, the controller is configured to restrict the travel speed of the milling machine under the maximum travel speed.

3. The system of claim 1, wherein, in response to the condition, the controller is configured to provide an alert via an output device.

4. The system of claim 1, wherein, in response to the condition, the controller is configured to limit the travel speed of the milling machine incrementally with respect to the maximum travel speed as the extension height value increases incrementally above the height value threshold.

5. The system of claim 1, wherein each sensor of the one or more sensors includes a position sensor configured to detect the extension by sensing a displacement of an extension rod with respect to a cylinder of a corresponding actuator operable to extend the corresponding leg with respect to the corresponding traction device.

6. The system of claim 1, wherein each sensor of the one or more sensors includes a proximity switch configured to detect the extension by sensing a displacement of a column associated with the one or more legs with respect to the frame.

7. The system of claim 1, wherein the one or more legs are rearward legs ofthe milling machine with respect to a travel direction of the milling machine.

8. A method for operating a milling machine, the method comprising: detecting, via one or more sensors, an extension of one or more legs of the milling machine correspondingly with respect to one or more traction devices of the milling machine, wherein the one or more legs extend with respect to the one or more traction devices to raise or lower a frame of the milling machine with respect to the one or more traction devices;determining, by a controller, a travel speed of the milling machine;computing, by the controller, an extension height value of the one or more legs based on the extension of the one or more legs; anddetermining, by the controller, a condition to limit the travel speed of the milling machine up to a maximum travel speed when the extension height value exceeds a height value threshold.

9. The method of claim 8, further including:restricting, by the controller, the travel speed of the milling machine under the maximum travel speed in response to the condition.

10. The method of claim 8, further including:providing, by the controller, an alert via an output device in response to the condition.

11. The method of claim 8, further including:limiting, by the controller, the travel speed of the milling machine incrementally with respect to the maximum travel speed as the extension height value increases incrementally above the height value threshold in response to the condition.

12. The method of claim 8, wherein each sensor of the one or more sensors includes a position sensor and wherein the detecting includes:detecting, by the position sensor, the extension by sensing a displacement of an extension rod with respect to a cylinder of a corresponding actuator operable to extend the corresponding leg with respect to the corresponding traction device.

13. The method of claim 8, wherein each sensor of the one or more sensors includes a proximity switch and wherein the detecting includes:detecting, by the proximity switch, the extension by sensing a displacement of a column associated with the one or more legs with respect to the frame.

14. The method of claim 8, wherein the one or more legs are rearward legs of the milling machine with respect to a travel direction of the milling machine.

15. A milling machine comprising:a frame;a milling chamber supported by the frame;one or more traction devices to provide tractive force to the milling machine;one or more legs coupled to the frame and the one or more traction devices, the one or more legs being extendable with respect to the one or more traction devices to raise or lower the frame of the milling machine with respect to the one or more traction devices; anda system for operating the milling machine, the system including:one or more sensors configured to detect an extension of the one or more legs of the milling machine correspondingly with respect to the one or more traction devices of the milling machine;a controller configured to:determine a travel speed of the milling machine;compute an extension height value of the one or more legs based on the extension of the one or more legs; anddetermine a condition to limit the travel speed of the milling machine up to a maximum travel speed when the extension height value exceeds a height value threshold.

16. The milling machine of claim 15, wherein, in response to the condition, the controller is configured to restrict the travel speed of the milling machine under the maximum travel speed.

17. The milling machine of claim 15, wherein, in response to the condition, the controller is configured to provide an alert via an output device.

18. The milling machine of claim 15, wherein, in response to the condition, the controller is configured to limit the travel speed of the milling machine incrementally with respect to the maximum travel speed as the extension height value increases incrementally above the height value threshold.

19. The milling machine of claim 15, wherein each sensor of the one or more sensors includes a position sensor configured to detect the extension by sensing a displacement of an extension rod with respect to a cylinder of a corresponding actuator operable to extend the corresponding leg with respect to the corresponding traction device.

20. The milling machine of claim 15, wherein each sensor of the one or more sensors includes a proximity switch configured to detect the extension by sensing a displacement of a column associated with the one or more legs with respect to the frame.

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