Automatic leveling method and device for tail end of feller

Abstract

The invention discloses a feller tail end automatic leveling method and device, and belongs to the technical field of felling machines. The method aims to solve the problem of leveling the trunk of the feller, and comprises the following steps: after the trunk clings to the feller, acquiring a vertical distance from a measurement plane of a laser ranging device to a saw plate plane and a laser ranging measurement value; generating an electromagnetic valve group electric signal according to the positive and negative results of the vertical distance and a comparison result of a set threshold value and a laser ranging measurement value so as to control a feeding roller to operate and enable the tree trunk to approach a saw plate plane; when the trunk gets close to the saw plate plane, whether the trunk tail end plane reaches the measurement plane or not is judged according to the comparison result of the set threshold value and the laser ranging measurement value; when the trunk tail end plane reaches the measuring plane, trunk feeding displacement is obtained; and according to a comparison result of a preset leveling threshold value and the trunk feeding displacement, whether the tail end of the trunk is leveled or not is determined so as to control the feeding roller to operate or stop. Trunk tail end leveling can be rapidly and accurately achieved, the operation process is simplified, and efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of automatic leveling method and device of feller-nibber end, belong to feller-nibber technical field. BACKGROUND

[0002] Feller-nibber is a key operation to the end face of tree when felling, so that the stump and wood end face after cutting are flat, facilitate post-processing, transportation and improve wood utilization rate;In the conventional work flow of feller-nibber, the feller climbs to the steep slope and uses the chainsaw to fell the tree, then the professional wood pulling machine drags the wood to the roadside and piles it up, and then the feller-nibber cuts the pile of wood into segments according to the predetermined size. However, the existing feller-nibber needs the operator to visually judge the cutting point, which may be affected by the line of sight obstruction or experience difference, resulting in uneven length of the wood after cutting and too long or short end, which cannot be recycled and is seriously wasted. At the same time, the operator needs to repeatedly adjust the feeding button during cutting, which is low in efficiency and easy to cause waste due to operation error. Therefore, the existing feller-nibber has the problems of too much manual intervention and low efficiency.

[0003] In order to solve the above problems, the existing technology introduces laser measurement technology to guide the leveling of feller-nibber, such as CN112889620A which uses two laser sensors to control the end face of the tree to the middle of the two sensors as the sign of leveling completion. This scheme needs to move the tree repeatedly during use, and cannot accurately control the end under the saw, so the overall efficiency is low and the accuracy is not high. Therefore, there is a need for a high-efficiency and accurate leveling method in the field of felling to eliminate the influence of manual intervention and achieve the purpose of improving the accuracy of felling end position and reducing wood waste. SUMMARY

[0004] The purpose of the present application is to provide an automatic leveling method and device for the end of feller-nibber, which aims to solve the above problems. The present application uses a combination of laser ranging device and length measuring device to quickly and efficiently control the movement of the feed roller with the tree trunk, accurately align the tree with the saw plate plane, realize the leveling of the end of the tree trunk, and reduce the number of laser sensors used, thereby reducing the cost of the whole machine and the probability of component damage.

[0005] To solve the above technical problems, the present application is realized by using the following technical scheme.

[0006] In the first aspect, the present application provides an automatic leveling method for the end of feller-nibber, comprising:

[0007] After the tree trunk is close to the feller-nibber, the vertical distance from the laser ranging device measurement plane to the saw plate plane and the laser ranging measurement value are obtained;

[0008] Based on the positive and negative results of the vertical distance and the comparison results between the set threshold and the laser ranging measurement value, an electrical signal is generated for the solenoid valve group to control the operation of the feed roller, so that the tree trunk moves closer to the saw blade plane.

[0009] As the tree trunk approaches the saw blade plane, the system determines whether the end plane of the tree trunk has reached the measurement plane based on the comparison between the set threshold and the laser ranging measurement value.

[0010] The trunk feeding displacement is obtained when the plane at the end of the trunk reaches the measuring plane;

[0011] Based on the comparison between the preset leveling threshold and the trunk feeding displacement, it is determined whether the end of the trunk is leveled, so as to control the operation or stop of the feeding roller.

[0012] Optionally, based on the positive or negative result of the vertical distance and the comparison result between the set threshold and the laser ranging measurement value, an electrical signal for the solenoid valve group is generated to control the operation of the feed roller, including:

[0013] If the vertical distance is positive and the measured value of the laser rangefinder is greater than the set threshold, it is determined that the plane at the end of the tree trunk is above the plane measured by the laser rangefinder. At this time, the first electrical signal of the solenoid valve group is generated to control the feed roller to rotate forward, driving the tree trunk to move down toward the saw blade plane.

[0014] If the vertical distance is negative and the measured value of the laser rangefinder is less than or equal to the set threshold value, it is determined that the plane at the end of the tree trunk is below the measuring plane of the laser rangefinder. At this time, a second electrical signal is generated for the solenoid valve group to control the feed roller to reverse and drive the tree trunk to move upward toward the saw blade plane.

[0015] Optionally, as the tree trunk approaches the saw blade plane, a comparison between a set threshold and the laser ranging measurement value is used to determine whether the end plane of the tree trunk reaches the measurement plane, including:

[0016] After the feed roller rotates forward, if the measured value of the laser rangefinder is less than or equal to the set threshold, it is determined that the end of the trunk has moved from top to bottom onto the measuring plane, and the trunk feeding displacement is obtained at this time.

[0017] Optionally, as the tree trunk approaches the saw blade plane, determining whether the end plane of the tree trunk has reached the measurement plane based on a comparison between a set threshold and the laser ranging measurement value, further includes:

[0018] After the feed roller reverses, if the instantaneous measurement value of the laser rangefinder is greater than the set threshold, it is determined that the end of the trunk has moved from the bottom to the upper measurement plane, and the trunk feed displacement is obtained at this time.

[0019] Optionally, based on a comparison between a preset leveling threshold and the trunk feeding displacement, it is determined whether the end of the trunk has been leveled, in order to control the operation or stop of the feeding roller, including:

[0020] If the trunk feeding displacement is equal to the leveling threshold, it is determined that the end of the trunk and the saw blade are on the same plane. The leveling control solenoid valve group is de-energized, and the feeding roller stops.

[0021] If the trunk feeding displacement does not reach the leveling threshold, it is determined that the end of the trunk has not reached the saw blade, and the leveling solenoid valve group cannot continue to be energized. The feeding roller will then continue to rotate forward or backward until the trunk feeding displacement equals the leveling threshold and stops.

[0022] Optionally, the leveling threshold is determined based on the vertical distance from the laser rangefinder's measuring plane to the saw blade plane and the vertical movement distance of the tree trunk end toward the measuring plane;

[0023] If the end of the tree trunk moves from top to bottom onto the measuring plane, the leveling threshold is the sum of the movement value of the end of the tree trunk and the vertical distance.

[0024] If the end of the tree trunk moves from bottom to top onto the measuring plane, the leveling threshold is the difference between the movement value of the end of the tree trunk and the vertical distance.

[0025] Secondly, the present invention provides an automatic leveling device for the end of a logging machine, comprising:

[0026] Controller, solenoid valve assembly, feed roller, laser rangefinder, length measuring device;

[0027] The controller is used to electrically connect the solenoid valve group, the laser rangefinder, and the length measuring device, and is used to execute the steps of the first aspect of the method;

[0028] The solenoid valve assembly is connected to the feed roller via a hydraulic pipeline and is used to control the operation or stop of the feed roller;

[0029] The laser rangefinder is used to detect the orientation of the end of the tree trunk.

[0030] The length measuring device is used to obtain the vertical displacement of the tree trunk during feeding.

[0031] Optionally, the feed roller, laser rangefinder, length measuring device, and saw blade are all arranged along the direction of trunk movement;

[0032] The laser rangefinder is installed above the saw blade, and the vertical distance from the laser rangefinder's measuring plane to the saw blade plane is a positive value.

[0033] Optionally, the laser rangefinder is installed below the saw blade, and the vertical distance from the laser rangefinder's measuring plane to the saw blade plane is negative.

[0034] Thirdly, the present invention provides a logging machine, including the leveling device described in the second aspect, wherein the feed roller, laser rangefinder, length measuring device and saw blade are all mounted on the frame of the logging machine.

[0035] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0036] This invention, through the combined use of a laser rangefinder and a length measuring device, can quickly and efficiently control the feed roller to move the tree trunk up and down, accurately align the tree trunk with the plane of the saw blade, achieve leveling of the tree trunk end, and at the same time reduce the number of laser sensors used, thereby reducing the overall machine cost and the probability of component damage.

[0037] The operator only needs to press a button once to issue a leveling command, and the controller can precisely move the end face of the wood to directly under the saw in two steps, thereby solving the problem of the first section of tree being of unacceptable length or wasting tree trunk, and ultimately greatly improving the accuracy and efficiency of leveling.

[0038] By coupling the length measurement information and the laser sensor information with the controller, the controller can determine the accurate relative position between the end of the tree trunk and the saw blade of the logging machine, and automatically control the feed roller to rotate forward, reverse or stop, reducing the complexity of operation and making the control more intelligent. Attached Figure Description

[0039] Figure 1 The diagram shows the flowchart of the automatic leveling method at the end of the logging machine according to the present invention.

[0040] Figure 2 The diagram shown is a structural diagram of the automatic leveling device at the end of the logging machine according to the present invention.

[0041] Figure 3 The diagram shown is a control structure diagram of the automatic leveling device at the end of the logging machine according to the present invention.

[0042] Figure 4 The figure shown is an embodiment of the automatic leveling device at the end of the logging machine according to the present invention.

[0043] In the diagram: 1. Feed roller; 2. Length measuring device; 3. Laser rangefinder; 4. Saw blade; 5. Controller; 6. Solenoid valve assembly; 7. Tree trunk. Detailed Implementation

[0044] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0045] Example 1

[0046] This embodiment provides a method for automatic leveling at the end of a logging machine, including:

[0047] Step 1: After the tree trunk is close to the logging machine, obtain the vertical distance from the laser rangefinder's measuring plane to the saw blade plane and the laser rangefinder's measured value;

[0048] Step 2: Based on the positive and negative results of the vertical distance and the comparison results between the set threshold and the laser ranging measurement value, generate an electrical signal for the solenoid valve group to control the operation of the feed roller and make the tree trunk move closer to the saw blade plane.

[0049] Step 3: When the tree trunk approaches the saw blade plane, determine whether the end plane of the tree trunk reaches the measurement plane based on the comparison result of the set threshold and the laser ranging measurement value.

[0050] Step 4: When the plane at the end of the tree trunk reaches the measuring plane, obtain the trunk feeding displacement;

[0051] Step 5: Based on the comparison between the preset leveling threshold and the trunk feeding displacement, determine whether the end of the trunk is leveled, so as to control the operation or stop of the feeding roller.

[0052] This embodiment introduces a length measuring device for end-point leveling, reducing the number of laser sensors and thus lowering overall machine cost and the likelihood of component damage. Furthermore, because it can detect the position of the trunk end in real time, the operator only needs to press a button once to issue a leveling command. The controller can then precisely move the wood end face directly under the saw in two steps, solving the problem of unqualified first-segment length or wasted trunk. Ultimately, this significantly improves leveling accuracy and efficiency. Compared to control methods using multiple laser sensors, this eliminates the need for repeated trunk movement, completely resolving the traditional problems of unqualified first-segment trunk length or wood waste, and achieving a significant improvement in leveling accuracy and efficiency. Figure 1 As shown, let d be the vertical distance from the laser rangefinder's measuring plane to the saw blade plane, l be the laser rangefinder's measured value, and x be the trunk's feeding displacement. When the trunk is directly below the laser rangefinder, the measured value is... Because each tree trunk, once embraced, will press tightly against the frame of the logging machine, therefore this The value will not differ significantly due to changes in the trunk diameter, therefore the specified value within the controller is... As a criterion for determining when the tree trunk is directly below the laser rangefinder, when there is no tree trunk below the laser rangefinder, the laser rangefinder measurement value in the controller is l >

[0053] Optionally, in step 2, based on the positive or negative result of the vertical distance and the comparison result between the set threshold and the laser ranging measurement value, an electrical signal for the solenoid valve group is generated to control the operation of the feed roller, including:

[0054] Step 2.1: If the vertical distance is positive and the measured value of the laser rangefinder is greater than the set threshold, then it is determined that the plane at the end of the tree trunk is above the plane measured by the laser rangefinder. At this time, the first electrical signal of the solenoid valve group is generated to control the feed roller to rotate forward and drive the tree trunk to move down toward the saw blade plane.

[0055] Step 2.2: If the vertical distance is negative, and the measured value of the laser rangefinder is less than or equal to the set threshold value, then it is determined that the plane of the tree trunk end is below the measuring plane of the laser rangefinder. At this time, a second electrical signal is generated for the solenoid valve group to control the feed roller to reverse, causing the tree trunk to move upward toward the saw blade plane.

[0056] In this embodiment, after the operator holds the tree trunk, if the command to find the end is issued and d > 0, the controller compares l with... The value of l, if l > This proves that the plane at the end of the tree trunk is above the measuring plane of the laser rangefinder (hereinafter referred to as the measuring plane). At this time, the controller supplies power to the solenoid valve group, driving the feed roller to rotate. If d < 0: Controller 5 compares l with... The value of l, if l≤ This proves that the end plane of the tree trunk 7 is below the measuring plane (hereinafter referred to as the measuring plane) of the laser rangefinder 3. At this time, the controller 5 supplies power to the solenoid valve group 6, driving the feed roller 1 to rotate in the opposite direction. The feed roller contacts the tree trunk and converts the rotational force into the power to move the tree trunk up or down, ensuring that the wood can smoothly enter the processing area according to the predetermined rhythm and force, and making full preparations for subsequent cutting and other processes.

[0057] Optionally, in step 3, as the tree trunk approaches the saw blade plane, a comparison between a set threshold and the laser ranging measurement value is used to determine whether the end plane of the tree trunk has reached the measurement plane, including:

[0058] Step A: After the feed roller rotates forward, if the measured value of the laser rangefinder is less than or equal to the set threshold, it is determined that the end of the trunk has moved from top to bottom onto the measurement plane, and the trunk feeding displacement is obtained at this time.

[0059] Step 3, when the tree trunk approaches the saw blade plane, determines whether the end plane of the tree trunk has reached the measurement plane based on the comparison result of the set threshold and the laser ranging measurement value. This also includes:

[0060] Step B: After the feed roller reverses, if the instantaneous measurement value of the laser rangefinder is greater than the set threshold, it is determined that the end of the trunk has moved from the bottom to the upper measurement plane, and the trunk feed displacement is obtained at this time.

[0061] In this embodiment, during the trunk's movement, the trunk moves downwards when rotating clockwise, and at a certain instant, l is no longer greater than... This proves that the plane at the end of tree trunk 7 lies on the measurement plane; at this point, record... When the tree trunk reverses, it moves upwards. When l is greater than a certain instant... This proves that the plane at the end of tree trunk 7 lies on the measurement plane; at this point, record... .

[0062] Optionally, in step 5, based on the comparison between the preset leveling threshold and the trunk feeding displacement, it is determined whether the end of the trunk has been leveled, so as to control the operation or stop of the feeding roller, including:

[0063] If the trunk feeding displacement is equal to the leveling threshold, it is determined that the end of the trunk and the saw blade are on the same plane. The leveling control solenoid valve group is de-energized, and the feeding roller stops.

[0064] If the trunk feeding displacement does not reach the leveling threshold, it is determined that the end of the trunk has not reached the saw blade, and the leveling solenoid valve group cannot continue to be energized. The feeding roller will then continue to rotate forward or backward until the trunk feeding displacement equals the leveling threshold and stops.

[0065] Optionally, the leveling threshold is determined based on the vertical distance from the laser rangefinder's measuring plane to the saw blade plane and the vertical movement distance of the tree trunk end toward the measuring plane;

[0066] If the end of the tree trunk moves from top to bottom onto the measuring plane, the leveling threshold is the sum of the movement value of the end of the tree trunk and the vertical distance.

[0067] If the end of the tree trunk moves from bottom to top onto the measuring plane, the leveling threshold is the difference between the movement value of the end of the tree trunk and the vertical distance.

[0068] In this embodiment, after the tree trunk reaches the measuring plane, if the forward rotation controller 5 continues to supply power, it drives the feed roller 1 to rotate until... At this point, the end of the tree trunk is on the same horizontal plane as saw blade 4, and leveling is complete. If the value being compared is l≤ Then, controller 5 supplies power to solenoid valve group 6, driving feed roller 1 to rotate in the opposite direction, causing tree 7 to move upward until l> Repeat the previous leveling process. If the direction reverses, controller 5 continues to supply power, driving feed roller 1 to rotate until... At this point, the end of the tree trunk is on the same horizontal plane as saw blade 4, and leveling is complete. If the value being compared is l > Then, controller 5 supplies power to solenoid valve group 6, driving feed roller 1 to rotate, causing tree 7 to move downwards until l ≤ Repeat the leveling process described above.

[0069] Example 2

[0070] This embodiment provides an automatic leveling device for the end of a logging machine, such as... Figures 2 to 4The device includes: a controller 5, a solenoid valve assembly 6, a feed roller 1, a laser rangefinder 3, and a length measuring device 2. The controller 5 is used to electrically connect the solenoid valve assembly 6, the laser rangefinder 3, and the length measuring device 2 to execute the steps of the method in Example 1. The solenoid valve assembly 6 is connected to the feed roller 1 through a hydraulic line and is used to control the operation or stop of the feed roller 1. The laser rangefinder 3 is used to detect the orientation of the end of the trunk 7. The length measuring device 2 is used to obtain the vertical feeding displacement of the trunk 7.

[0071] Optionally, the feed roller 1, laser rangefinder 3, length measuring device 2, and saw blade 4 are all arranged along the moving direction of the trunk 7;

[0072] The laser rangefinder 3 is installed above the saw blade 4, and the vertical distance from the plane of the laser rangefinder 3 to the plane of the saw blade 4 is a positive value.

[0073] Optionally, the laser rangefinder 3 is installed below the saw blade 4, and the vertical distance from the plane of the laser rangefinder 3 to the plane of the saw blade 4 is a negative value.

[0074] Example 3

[0075] This embodiment provides a logging machine, including the leveling method of Embodiment 1 and the leveling device of Embodiment 2. The feed roller, laser rangefinder, length measuring device and saw blade are all installed on the frame of the logging machine.

[0076] In summary, this invention, through the combined use of a laser rangefinder and a length measuring device, can quickly and efficiently control the feed roller to move the tree trunk up and down, precisely aligning the trunk with the saw blade plane to achieve leveling of the trunk end. Simultaneously, it reduces the number of laser sensors required, thereby reducing overall machine cost and the likelihood of component damage. The operator only needs to press a button once to issue the leveling command, and the controller can precisely move the wood end face directly under the saw in two steps, thus solving the problem of unqualified first-segment tree length or wasted trunk, ultimately greatly improving the accuracy and efficiency of leveling.

[0077] By coupling the length measurement information and the laser sensor information with the controller, the controller can determine the accurate relative position between the end of the tree trunk and the saw blade of the logging machine, and automatically control the feed roller to rotate forward, reverse or stop, reducing the complexity of operation and making the control more intelligent.

[0078] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0079] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0080] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0081] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0082] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for automatic leveling at the end of a logging machine, characterized in that, include: After the tree trunk is close to the logging machine, the vertical distance from the laser rangefinder's measuring plane to the saw blade plane and the laser rangefinder measurement value are obtained. Based on the positive and negative results of the vertical distance and the comparison results between the set threshold and the laser ranging measurement value, an electrical signal is generated for the solenoid valve group to control the operation of the feed roller, so that the tree trunk moves closer to the saw blade plane. As the tree trunk approaches the saw blade plane, the system determines whether the end plane of the tree trunk has reached the measurement plane based on the comparison between the set threshold and the laser ranging measurement value. The trunk feeding displacement is obtained when the plane at the end of the trunk reaches the measuring plane; Based on the comparison between the preset leveling threshold and the trunk feeding displacement, it is determined whether the end of the trunk is leveled, so as to control the operation or stop of the feeding roller.

2. The automatic leveling method for the end of a logging machine according to claim 1, characterized in that, Based on the positive or negative result of the vertical distance and the comparison between the set threshold and the laser ranging measurement value, an electrical signal for the solenoid valve group is generated to control the operation of the feed roller, including: If the vertical distance is positive and the measured value of the laser rangefinder is greater than the set threshold, it is determined that the plane at the end of the tree trunk is above the plane measured by the laser rangefinder. At this time, the first electrical signal of the solenoid valve group is generated to control the feed roller to rotate forward, driving the tree trunk to move down toward the saw blade plane. If the vertical distance is negative and the measured value of the laser rangefinder is less than or equal to the set threshold value, it is determined that the plane at the end of the tree trunk is below the measuring plane of the laser rangefinder. At this time, a second electrical signal is generated for the solenoid valve group to control the feed roller to reverse and drive the tree trunk to move upward toward the saw blade plane.

3. The automatic leveling method for the end of a logging machine according to claim 2, characterized in that, As the tree trunk approaches the saw blade plane, the system determines whether the end plane of the tree trunk reaches the measurement plane based on a comparison between a set threshold and the laser ranging measurement value. This includes: After the feed roller rotates forward, if the measured value of the laser rangefinder is less than or equal to the set threshold, it is determined that the end of the trunk has moved from top to bottom onto the measuring plane, and the trunk feeding displacement is obtained at this time.

4. The automatic leveling method for the end of a logging machine according to claim 2, characterized in that, As the tree trunk approaches the saw blade plane, the system determines whether the end plane of the tree trunk has reached the measurement plane based on a comparison between a set threshold and the laser ranging measurement value. This also includes: After the feed roller reverses, if the instantaneous measurement value of the laser rangefinder is greater than the set threshold, it is determined that the end of the trunk has moved from the bottom to the upper measurement plane, and the trunk feed displacement is obtained at this time.

5. The automatic leveling method for the end of a logging machine according to claim 1, characterized in that, Based on the comparison between the preset leveling threshold and the trunk feeding displacement, it is determined whether the end of the trunk has been leveled, thereby controlling the operation or stopping of the feeding roller, including: If the trunk feeding displacement is equal to the leveling threshold, it is determined that the end of the trunk and the saw blade are on the same plane. The leveling control solenoid valve group is de-energized, and the feeding roller stops. If the trunk feeding displacement does not reach the leveling threshold, it is determined that the end of the trunk has not reached the saw blade, and the leveling solenoid valve group cannot continue to be energized. The feeding roller will then continue to rotate forward or backward until the trunk feeding displacement equals the leveling threshold and stops.

6. The automatic leveling method for the end of a logging machine according to claim 1, characterized in that, The leveling threshold is determined based on the vertical distance from the laser rangefinder's measuring plane to the saw blade plane and the vertical movement distance of the tree trunk end toward the measuring plane. If the end of the tree trunk moves from top to bottom onto the measuring plane, the leveling threshold is the sum of the movement value of the end of the tree trunk and the vertical distance. If the end of the tree trunk moves from bottom to top onto the measuring plane, the leveling threshold is the difference between the movement value of the end of the tree trunk and the vertical distance.

7. An automatic leveling device for the end of a logging machine, characterized in that, include: Controller, solenoid valve assembly, feed roller, laser rangefinder, length measuring device; The controller is used to electrically connect the solenoid valve group, the laser rangefinder, and the length measuring device, and is used to execute the steps of the automatic leveling method according to any one of claims 1 to 6; The solenoid valve assembly is connected to the feed roller via a hydraulic pipeline and is used to control the operation or stop of the feed roller; The laser rangefinder is located on one side of the saw blade and is used to detect the orientation of the end of the tree trunk; The length measuring device is used to obtain the vertical displacement of the tree trunk during feeding.

8. The automatic leveling device at the end of the logging machine according to claim 7, wherein the feed roller, laser rangefinder, length measuring device and saw blade are all arranged along the direction of trunk movement; The laser rangefinder is installed above the saw blade, and the vertical distance from the laser rangefinder's measuring plane to the saw blade plane is a positive value.

9. The automatic leveling device at the end of the logging machine according to claim 7, wherein the laser rangefinder is installed below the saw blade, and the vertical distance from the plane of the laser rangefinder to the plane of the saw blade is negative.

10. A logging machine, characterized in that, The system includes the leveling device as described in claim 7, wherein the feed roller, laser rangefinder, length measuring device, and saw blade are all mounted on the frame of the logging machine.

Images