Cantilever tunnel boring machine cutting arm bearing oil level detection device and method

Abstract

The present invention relates to the technical field of tunnel boring machine maintenance, and specifically to a cantilever tunnel boring machine cutting arm bearing oil level detection device, including an oil level sensing switch and a protective component, an oil inlet hole is arranged on the connecting tube of the cutting arm, the inner end of the oil inlet hole is connected to the bearing cavity in the connecting tube, the oil level sensing switch is connected to the oil inlet hole of the connecting tube, an induction switch detection head is arranged on the end of the oil level sensing switch inserted into the oil inlet hole, the position of the oil inlet hole is lower than the lubricating oil level of the bearing cavity when the cutting arm is in a horizontal state, the oil level sensing switch is electrically connected to the tunnel boring machine main controller; the protective component is fixedly connected to the outside of the connecting tube; a cantilever tunnel boring machine cutting arm bearing oil level detection method, using the above-mentioned cantilever tunnel boring machine cutting arm bearing oil level detection device for detection. The present invention can realize automatic detection of the oil level of the large bearing of the cutting arm, which can not only improve the detection work efficiency and reduce the probability of safety accidents, but also has good reliability, convenient and timely detection of oil leakage and replacement of floating seals.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel boring machine maintenance, and in particular to a device and method for detecting the oil level of a cutting arm bearing of a cantilever tunnel boring machine. Background Art

[0002] The cutting arm is the core component of the cantilever roadheader, and its reliability directly affects the performance and work efficiency of the whole machine. The large bearing is located at the front end of the cutting arm and bears most of the axial and radial forces generated by tunneling. Therefore, it is very important to ensure the normal operation of the large bearing. In the actual application of the cutting arm on site, the large bearing is mostly damaged prematurely due to lack of oil and muddy water pollution caused by damage to the floating seal. If the oil leakage can be discovered in time and the floating seal is replaced, the premature damage of the bearing can be avoided. Therefore, the bearing oil level needs to be checked frequently.

[0003] At present, the oil level of the cutting arm is mainly checked manually. When checking, first adjust the lifting cylinder of the cutting part so that the cutting part is roughly horizontal with the ground, then unscrew the oil overflow plug on the connecting tube, and observe the lubricating oil level in the bearing cavity. Since the oil overflow port is more than 2 meters above the ground when the cutting arm is horizontal, it is necessary to use tools to raise it or use an escalator to check it. It can be seen that manual inspection is not only unreliable and inefficient, but also unsafe. Summary of the invention

[0004] The purpose of the present invention is to provide a cantilever tunneling machine cutting arm bearing oil level detection device and method in view of the above-mentioned problems and shortcomings, which can realize automatic detection of the oil level of the cutting arm large bearing, not only improving the detection efficiency and reducing the probability of safety accidents among on-site workers, but also having good reliability, facilitating and timely detection of oil leakage and replacement of floating seals, and avoiding premature damage to the bearings.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution of the present invention is:

[0006] A cantilever tunneling machine cutting arm bearing oil level detection device, including an oil level sensing switch and a protective component, an oil inlet hole is arranged on the connecting tube of the cutting arm, the inner end of the oil inlet hole is connected to the bearing cavity in the connecting tube, the oil level sensing switch is connected to the oil inlet hole of the connecting tube, and an inductive switch detection head is arranged on the end of the oil level sensing switch inserted into the oil inlet hole, the position of the oil inlet hole is lower than the lubricating oil level of the bearing cavity when the cutting arm is in a horizontal state; the protective component is fixedly connected to the outer side of the connecting tube, and is used for protecting the oil level sensing switch and the sensing switch cable.

[0007] Furthermore, in the above-mentioned cantilever tunnel boring machine cutting arm bearing oil level detection device, the oil level sensing switch is electrically connected to the tunnel boring machine main controller, and the tunnel boring machine main controller is also electrically connected to the display device and / or the voice warning device.

[0008] Furthermore, in the above-mentioned cantilever tunnel boring machine cutting arm bearing oil level detection device, the cantilever tunnel boring machine cutting arm bearing oil level detection device also includes a linear displacement sensor, which is installed on the cutting arm lifting cylinder and is used to detect the position of the cutting arm relative to the ground. The linear displacement sensor is electrically connected to the tunnel boring machine main controller.

[0009] Furthermore, in the above-mentioned oil level detection device for the cutting arm bearing of a cantilever tunneling machine, the protective assembly includes an upper protective block, a lower protective block, a protective plate, a front protective cover, a protective cylinder and a rear protective cover. The upper protective block and the lower protective block are respectively arranged above and below the induction switch and welded to the outer circumferential surface of the connecting cylinder. A protective plate is welded on the side between the upper protective block and the lower protective block close to the cutting head. The front protective cover is fixed on the upper protective block and the lower protective block, and the rear protective cover is fixed on the rear flange of the connecting cylinder. The protective cylinder is located between the front protective cover and the rear protective cover, and is welded to the outer circumferential surface of the connecting cylinder along the axial direction of the connecting cylinder.

[0010] Furthermore, in the above-mentioned cantilever tunneling machine cutting arm bearing oil level detection device, the upper protective block and the lower protective block are provided with threaded holes, the front protective cover is fixed to the upper protective block and the lower protective block by bolts; the rear protective cover is fixed to the rear flange of the connecting cylinder by bolts.

[0011] Furthermore, in the above-mentioned oil level detection device for the cutting arm bearing of a cantilever tunneling machine, the front protective cover includes an arc-shaped cover plate and a side plate connected to one side of the arc-shaped cover plate, the outer side edge of the side plate is set to an arc line that matches the curvature of the arc-shaped cover plate, and the inner side edge is set to an arc line that matches the outer cylindrical surface of the connecting cylinder, and the side plate is provided with a connecting hole and a cable passing groove, and the front protective cover is fixed to the upper protective block and the lower protective block through the side plate.

[0012] Furthermore, in the above-mentioned oil level detection device for the cutting arm bearing of a cantilever tunneling machine, the rear protective cover includes a connecting plate and a cable protective cover, the inner and outer edges of the connecting plate are both set as arcs, and a connecting hole is provided on the connecting plate. The rear protective cover is fixed to the rear flange of the connecting tube through the connecting plate, one end of the cable protective cover is welded to the plate surface of the connecting plate, and the other end is covered on the outside of the end of the protective tube.

[0013] Furthermore, in the above-mentioned cantilever tunneling machine cutting arm bearing oil level detection device, the oil inlet hole is threaded on the inner wall of one end close to the outer circumferential surface of the connecting tube, and the induction switch is screwed to the connecting tube through the oil inlet hole.

[0014] A method for detecting the oil level of a cutting arm bearing of a cantilever tunneling machine is provided. The method uses any of the above-mentioned oil level detection devices for detecting the oil level of a cutting arm bearing of a cantilever tunneling machine to perform detection. First, the user looks at a display device in the tunneling machine cab and operates a handle to make the position angle α of the cutting arm relative to the ground reach 0±1 degrees. The position angle α of the cutting arm relative to the ground is calculated by the tunneling machine main controller by reading the data of a linear displacement sensor installed on the cutting arm lifting cylinder and displayed on the display device. Then, information on whether the bearing is leaking oil is obtained through the display device and / or a voice warning device. The oil leakage information is output by the tunneling machine main controller by reading the data of the oil level sensing switch and controlling the display device and / or the voice warning device.

[0015] Furthermore, in the above-mentioned method for detecting the oil level of the cutting arm bearing of a cantilever tunneling machine, the calculation formula of the angle α of the cutting arm relative to the ground position is:

[0016] Among them, L1 is the straight-line distance between the front and rear hinges of the cutting frame, L2 is the straight-line distance between the upper and lower hinges of the turntable, L3 is the installation distance of the cutting arm lifting cylinder, X is the telescopic amount of the cutting arm lifting cylinder, which is obtained by reading the data of the linear displacement sensor, γ is the angle between the axial center line of the cutting arm and L1, δ is the angle of L2 relative to the ground, and β is the angle of the lifting cylinder relative to the ground.

[0017] Beneficial effects of the device and method for detecting the oil level of the cutting arm bearing of a cantilever tunneling machine of the present invention:

[0018] The cantilever tunnel boring machine cutting arm bearing oil level detection device of the present invention can realize automatic detection of the oil level of the cutting arm large bearing by arranging an oil level sensing switch on the connecting tube for detecting whether the cutting arm is short of oil when the cutting arm is in the horizontal position, thereby improving the detection work efficiency and reducing the probability of safety accidents for on-site workers. The tunnel boring machine main controller is electrically connected with the oil level sensing switch, the display device and / or the voice warning device, so that the driver can directly observe the detection result in the cab conveniently. By arranging a linear displacement sensor for detecting the position of the cutting arm relative to the ground on the cutting arm lifting cylinder, it is convenient to accurately control the angle of the cutting arm, so that the automatic detection of the oil level of the cutting arm large bearing has good reliability, and it is convenient to find oil leakage in time and replace the floating seal, so as to avoid premature damage to the bearing. By arranging a protective component, it is feasible to arrange the oil level sensing switch in the complex environment of the connecting tube position.

[0019] The oil level detection method for the cutting arm bearing of a cantilever tunneling machine of the present invention can not only improve the detection efficiency and reduce the probability of safety accidents occurring to on-site workers, but also has good reliability and is convenient for timely detecting oil leakage and replacing floating seals. In addition, through the cutting arm position angle calculation method, the cutting arm position angle can be cleverly obtained according to the linear displacement of the cutting arm lifting cylinder. Since the data accuracy of the linear displacement sensor is high, the cutting arm position angle obtained according to the linear displacement sensor is also more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a schematic structural diagram of a device for detecting an oil level in a cutting arm bearing of a boom boring machine according to an embodiment of the present invention.

[0021] Figure 2 yes Figure 1 AA cross-sectional structure schematic diagram.

[0022] Figure 3 Schematic diagram of the structure of a protective member welded on the outer circumferential surface of a connecting cylinder according to an embodiment of the present invention.

[0023] Figure 4 It is a schematic structural diagram of a protection component connected to the outer circumferential surface of a connecting cylinder according to an embodiment of the present invention.

[0024] Figure 5 2 is a schematic structural diagram of a front protective cover according to an embodiment of the present invention.

[0025] Figure 6 is a schematic structural diagram of a rear protective cover according to an embodiment of the present invention.

[0026] Figure 7 4 is a schematic diagram of the calculation of the position angle of the cutting arm according to an embodiment of the present invention.

[0027] Figure 8 The present invention is a block diagram of the working principle of a cantilever tunneling machine bearing oil level detection device according to an embodiment of the present invention.

[0028] In the figure: 1 is the cutting arm lifting cylinder, 2 is the linear displacement sensor, 3 is the connecting tube, 4 is the oil level sensing switch, 5 is the upper protective block, 6 is the lower protective block, 7 is the protective plate, 8 is the protective tube, 9 is the front protective cover, 91 is the arc cover plate, 92 is the side plate, 10 is the rear protective cover, 101 is the connecting plate, 102 is the cable protective cover, 11 is the oil inlet hole, 12 is the oil inlet hole thread, 13 is the detection switch probe, 14 is the bolt, 15 is the rear flange of the connecting tube, 16 is the bearing cavity, 17 is the turntable, and 18 is the cutting frame. DETAILED DESCRIPTION

[0029] The following is a more detailed description of a cantilever tunneling machine cutting arm bearing oil level detection device and method of the present invention in conjunction with the accompanying drawings and through specific implementations.

[0030] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0031] See also Figure 1-Figure 8 The present embodiment discloses an oil level detection device for the bearing of a cutting arm of a cantilevered tunnel boring machine, including an oil level sensing switch and a protection component. An oil inlet hole is arranged on the connecting tube of the cutting arm, and the inner end of the oil inlet hole is communicated with the bearing cavity in the connecting tube. The bearing cavity is an oil storage cavity between the front and rear seals of the large bearing of the cutting arm. The oil level sensing switch is connected to the oil inlet hole of the connecting tube. An induction switch detection head is arranged on the end of the oil level sensing switch inserted into the oil inlet hole, which is used to automatically detect whether the cutting arm is short of oil when the cutting arm is in a horizontal position. When the position of the oil inlet hole is lower than that of the bearing when the cutting arm is in a horizontal state, the oil level sensing switch is connected to the oil inlet hole of the connecting tube. The lubricating oil level in the cavity is measured, and the sensing switch detection head is immersed in the lubricating oil. When oil leakage occurs, the oil inlet hole will be higher than the lubricating oil level, the switch detection head will be separated from the lubricating oil and generate a signal, which can improve the detection efficiency and reduce the probability of safety accidents for on-site workers; the protective component is fixedly connected to the outside of the connecting cylinder, and the connecting cylinder is close to the cutting head of the cutting arm, and the external environment is harsh. Therefore, it is necessary to set a protective component to protect the oil level sensing switch and the sensing switch cable, so that it is feasible to set the oil level sensing switch in the complex environment of the connecting cylinder.

[0032] In this embodiment, preferably, the oil level sensing switch is electrically connected to the main controller of the tunnel boring machine, and the main controller of the tunnel boring machine is also electrically connected to the display device and / or the voice warning device, which can facilitate the driver to directly observe the detection results in the cab. On the basis of the above scheme, more preferably, the cantilever tunnel boring machine cutting arm bearing oil level detection device also includes a linear displacement sensor, which is installed on the cutting arm lifting cylinder and is used to detect the position of the cutting arm relative to the ground. The linear displacement sensor is electrically connected to the main controller of the tunnel boring machine. The linear displacement sensor is provided to facilitate the precise control of the angle of the cutting arm, so that the automatic detection of the oil level of the large bearing of the cutting arm is reliable. The main controller of the tunnel boring machine reads the displacement sensor, the inductive switch data or signal, and after processing, outputs the cutting arm position angle, whether there is oil shortage and other information to the display device or voice warning device electrically connected to the main controller, so as to facilitate timely detection of oil leakage and replacement of floating seals to avoid premature damage to the bearings.

[0033] In this embodiment, preferably, the protective assembly includes an upper protective block, a lower protective block, a protective plate, a front protective cover, a protective tube and a rear protective cover. The upper protective block and the lower protective block are respectively arranged above and below the sensing switch and welded to the outer circumferential surface of the connecting tube to prevent the sensing switch from being squeezed during the cutting process. A protective plate is welded on the side between the upper protective block and the lower protective block close to the cutting head to prevent the material blocks brought up by the rotation of the cutting head from wearing the sensing switch. The front protective cover is fixed on the upper protective block and the lower protective block, and the rear protective cover is fixed on the rear flange of the connecting tube. The protective tube is located between the front protective cover and the rear protective cover, and is welded to the outer circumferential surface of the connecting tube along the axial direction of the connecting tube for protecting the sensing switch cable.

[0034] In this embodiment, preferably, threaded holes are provided on the upper and lower protective blocks, and the front protective cover is fixed to the upper and lower protective blocks by bolts; the rear protective cover is fixed to the rear flange of the connecting tube by bolts. The threaded connection is convenient for maintenance of the oil level sensor switch and the sensor switch cable.

[0035] In this embodiment, preferably, the front protective cover includes a curved cover plate and a side plate connected to one side of the curved cover plate, the outer side edge of the side plate is set to an arc that matches the curvature of the curved cover plate, and the inner side edge is set to an arc that matches the outer cylindrical surface of the connecting tube. The shapes of the curved cover plate and the side plate make the front protective cover fit more closely to the surface of the connecting tube and are not easily damaged. The side plate is provided with connecting holes and cable passing grooves. The front protective cover is fixed to the upper protective block and the lower protective block through the connecting holes on the side plate, bolts and threaded holes on the upper protective block and the lower protective block. The position of the bolts makes it difficult to be hit or damaged. The front protective cover serves to protect the oil level sensing switch and the sensing switch cable.

[0036] In this embodiment, preferably, the rear protective cover includes a connecting plate and a cable protective cover, the inner and outer edges of the connecting plate are set as arcs, so that it is convenient to fix it to the rear flange of the connecting tube, and a connecting hole is provided on the connecting plate. The rear protective cover is fixed to the rear flange of the connecting tube through the connecting plate. One end of the cable protective cover is connected to the plate surface of the arc-shaped connecting plate, and the other end is covered on the outside of the end of the protective tube, which can protect the induction switch cable at the end of the protective tube. The rear protective cover can prevent the material blocks that fall during the cutting process from hitting the induction switch cable.

[0037] In this embodiment, preferably, a thread is processed on the inner wall of one end of the oil inlet hole close to the outer circumferential surface of the connecting tube, and the sensing switch is screwed to the connecting tube through the oil inlet hole, which facilitates the connection and disassembly of the oil level sensing switch.

[0038] A method for detecting the oil level of the cutting arm bearing of a cantilever tunneling machine is provided. The oil level detection device for the cutting arm bearing of the cantilever tunneling machine is used for detection. First, the user looks at the display device in the tunneling machine cab and operates the handle to make the position angle α of the cutting arm relative to the ground reach 0±1 degrees. The position angle α of the cutting arm relative to the ground is calculated by the tunneling machine main controller by reading the data of the linear displacement sensor installed on the cutting arm lifting cylinder and displayed on the display device. Then, the information on whether the bearing is leaking oil is obtained through the display device and / or the voice warning device. The oil leakage information is output by the tunneling machine main controller by reading the data of the oil level sensing switch and controlling the display device and / or the voice warning device. The detection method is simple and reliable to operate, has good safety and high detection efficiency, and is convenient for timely detection of oil leakage and replacement of floating seals.

[0039] In this embodiment, preferably, the calculation formula of the cutting arm position angle α relative to the ground is:

[0040] Among them, L1 is the straight-line distance between the front and rear hinges of the cutting frame (i.e., the hinge points between the cutting frame and the front end of the rotary table and the cutting arm lifting cylinder), L2 is the straight-line distance between the upper and lower hinges of the rotary table (the upper and lower hinges are the hinge points between the rotary table and the cutting frame and the cutting arm lifting cylinder, respectively), L3 is the installation distance of the cutting arm lifting cylinder, X is the telescopic amount of the cutting arm lifting cylinder, which is obtained by reading the data of the linear displacement sensor, γ is the angle between the axial center line of the cutting arm and L1, the axial center line of the cutting arm is the center line of the main shaft in the connecting tube, δ is the position angle of L2 relative to the ground, and β is the position angle of the lifting cylinder relative to the ground. Through the above calculation formula, the cutting arm position angle can be cleverly obtained according to the linear displacement of the cutting arm lifting cylinder. Due to the high data accuracy of the linear displacement sensor, the cutting arm position angle obtained according to the linear displacement sensor is also more accurate. In addition, through actual use, it is found that the detection hysteresis and accuracy of the cutting arm relative to the ground position angle α are better than those of general angle sensors.

[0041] Unless otherwise defined, the technical or scientific terms used herein shall have the usual meanings understood by persons of ordinary skill in the field to which the invention belongs. The use of "first", "second" and similar words in the specification and claims of this application does not indicate any order, quantity or importance, but is only used to distinguish different components. Similarly, the use of "one" or "an" and other similar words does not necessarily indicate a quantitative limitation. "Include" or "comprising" and other similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and other similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0042] The exemplary implementation modes of the present invention are described in detail above with reference to the preferred embodiments. However, it can be understood by those skilled in the art that, without departing from the concept of the present invention, various modifications and variations can be made to the above-mentioned specific embodiments, and various combinations of the technical features and structures proposed in the present invention can be made without exceeding the protection scope of the present invention.

Claims

1. A cantilever tunnel boring machine cutting arm bearing oil level detection device, characterized in that: It comprises an oil level sensing switch and a protection component. An oil inlet hole is arranged on the connecting tube of the cutting arm. The inner end of the oil inlet hole is communicated with the bearing cavity in the connecting tube. The oil level sensing switch is connected in the oil inlet hole of the connecting tube. An induction switch detection head is arranged on the end of the oil level sensing switch inserted into the oil inlet hole. The position of the oil inlet hole is lower than the lubricating oil level of the bearing cavity when the cutting arm is in a horizontal state. The protection component is fixedly connected to the outer side of the connecting tube and is used to protect the oil level sensing switch and the induction switch cable. The protective assembly includes an upper protective block, a lower protective block, a protective plate, a front protective cover, a protective tube and a rear protective cover. The upper protective block and the lower protective block are respectively arranged on the upper and lower sides of the induction switch and welded to the outer circumferential surface of the connecting tube. A protective plate is welded on the side between the upper protective block and the lower protective block close to the cutting head. The front protective cover is fixed on the upper protective block and the lower protective block, and the rear protective cover is fixed on the rear flange of the connecting tube. The protective tube is located between the front protective cover and the rear protective cover, and is welded to the outer circumferential surface of the connecting tube along the axial direction of the connecting tube.

2. The cantilever tunnel boring machine cutting arm bearing oil level detection device according to claim 1, characterized in that: The oil level sensing switch is electrically connected to a main controller of the tunnel boring machine, and the main controller of the tunnel boring machine is also electrically connected to a display device and / or a voice warning device.

3. The cantilever tunnel boring machine cutting arm bearing oil level detection device according to claim 2, characterized in that: The cantilever tunneling machine cutting arm bearing oil level detection device also includes a linear displacement sensor, which is installed on the cutting arm lifting cylinder and is used to detect the position of the cutting arm relative to the ground. The linear displacement sensor is electrically connected to the tunneling machine main controller.

4. The oil level detection device for the cutting arm bearing of a cantilever tunneling machine according to claim 1, characterized in that: The upper protective block and the lower protective block are provided with threaded holes, the front protective cover is fixed to the upper protective block and the lower protective block by bolts; the rear protective cover is fixed to the rear flange of the connecting cylinder by bolts.

5. The cantilever tunnel boring machine cutting arm bearing oil level detection device according to claim 4, characterized in that: The front protective cover includes a curved cover plate and a side plate connected to one side of the curved cover plate, the outer side edge of the side plate is set as an arc that matches the curvature of the curved cover plate, and the inner side edge is set as an arc that matches the outer circular surface of the connecting cylinder, and the side plate is provided with a connecting hole and a cable passing groove, and the front protective cover is fixed to the upper protective block and the lower protective block through the side plate.

6. The cantilever tunnel boring machine cutting arm bearing oil level detection device according to claim 4, characterized in that: The rear protective cover includes a connecting plate and a cable protective cover. The inner and outer sides of the connecting plate are both set as arcs. A connecting hole is provided on the connecting plate. The rear protective cover is fixed to the rear flange of the connecting tube through the connecting plate. One end of the cable protective cover is connected to the plate surface of the arc-shaped connecting plate, and the other end is covered on the outside of the end of the protective tube.

7. The cantilever tunnel boring machine cutting arm bearing oil level detection device according to claim 1, characterized in that: The inner wall of one end of the oil inlet hole close to the outer circumferential surface of the connecting cylinder is processed with a thread, and the induction switch is screwed on the connecting cylinder through the oil inlet hole.

8. A method for detecting the oil level of a cutting arm bearing of a cantilever tunneling machine, characterized in that: The oil level detection device for the cutting arm bearing of a cantilever tunnel boring machine as described in any one of claims 1 to 7 is used for detection. First, the display device is looked at in the tunnel boring machine cab and the handle is operated to make the position angle α of the cutting arm relative to the ground reach 0±1 degree. The position angle α of the cutting arm relative to the ground is calculated by the tunnel boring machine main controller by reading the data of the linear displacement sensor installed on the cutting arm lifting cylinder and displayed on the display device. Then, the information on whether the bearing is leaking oil is obtained through the display device and / or the voice warning device. The oil leakage information is output by the tunnel boring machine main controller by reading the data of the oil level sensing switch and controlling the display device and / or the voice warning device.

9. A method for detecting oil level of a cutting arm bearing of a cantilever tunneling machine according to claim 8, characterized in that: The calculation formula of the cutting arm angle α relative to the ground is: , , where L1 is the straight-line distance between the front and rear hinges of the cutting frame, L2 is the straight-line distance between the upper and lower hinges of the turntable, L3 is the installation distance of the cutting arm lifting cylinder, X is the telescopic amount of the cutting arm lifting cylinder, which is obtained by reading the data of the linear displacement sensor, γ is the angle between the axial center line of the cutting arm and L1, δ is the angle of L2 relative to the ground, and β is the angle of the lifting cylinder relative to the ground.

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