A center of gravity control system, a shovel, and a center of gravity control method for a shovel

Abstract

This invention discloses a center of gravity control system, an excavator, and a method for controlling the center of gravity of the excavator. The center of gravity control system includes a turntable, a center of gravity detector, a servo motor pump, a counterweight mechanism, and a controller. The controller is connected to both the center of gravity detector and the servo motor pump, receiving center of gravity position signals from the detector and controlling the servo motor pump to steer, causing liquid in the first and / or second liquid counterweight tanks to flow towards the solid-liquid mixture counterweight tank, or vice versa. The center of gravity control system provided by this invention has a simple structure and is easy to operate. The center of gravity control method enables manual and automatic adjustment of the machine's center of gravity, effectively improving the stability of the entire machine and enabling the excavator to adapt to multiple working conditions and perform multiple functions.

Description

Technical Field

[0001] This invention belongs to the field of engineering machinery technology, specifically relating to a center of gravity control system, an excavator, and a method for controlling the center of gravity of an excavator. Background Technology

[0002] Excavators require different counterweights under different working conditions and with different attachments. Therefore, when changing attachments or working under special conditions, the overall stability of the machine will deteriorate. To meet stability requirements, excavators generally use pre-packaged counterweights (usually solid) with matching dimensions. However, due to the shape of the counterweight and the space available for installation, the adjustment of the counterweight cannot be precisely controlled. Furthermore, the counterweight is relatively heavy, requiring transport vehicles and specialized replacement equipment, which cannot meet the center of gravity adjustment needs during field operations.

[0003] Currently, excavators generally use two methods to adjust the overall center of gravity: one is to add a counterweight. This involves using pre-filled counterweights of matching dimensions to simply increase the weight of the vehicle, thus adjusting the center of gravity. The drawback of this method is that the center of gravity needs to be adjusted whenever the implements are changed, making the operation cumbersome. Furthermore, the shape and installation space of the counterweight limit precise control, and the counterweight's large mass requires transport vehicles and specialized replacement equipment, making it unsuitable for adjusting the center of gravity during field operations. The other method is to use a sliding counterweight, which uses hydraulic cylinders... The counterweight is pushed out or retracted by mechanical tools, and the center of gravity is adjusted by gravitational torque. The disadvantage of this method is that although the hydraulic cylinder can achieve real-time adjustment in the field, the adjustment of the center of gravity is highly random. Due to the limitation of the movement position of the hydraulic cylinder and push rod, the adjustment of the center of gravity cannot be precisely controlled. At the same time, because the counterweight is heavy, the hydraulic cylinder is subjected to large bending moments and impacts during operation for a long time, which can easily lead to rapid deformation and damage of the cylinder. In addition, since the sliding counterweight is adjusted by the hydraulic cylinder, it is greatly limited by the working space and construction site. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a center of gravity control system, an excavator, and a method for controlling the center of gravity of the excavator. The system has a simple structure and is easy to operate. It can realize manual and automatic adjustment of the center of gravity of the whole machine, effectively improve the stability of the whole machine, and realize the multi-condition adaptability and multi-purpose use of the excavator.

[0005] This invention provides the following technical solution:

[0006] In one aspect, a center of gravity control system is provided, including a turntable, a center of gravity detector, a servo motor pump, a counterweight mechanism, and a controller;

[0007] The turntable is connected to the slewing support through the slewing center, and the center of gravity detector is located between the turntable and the slewing support to monitor the center of gravity position and transmit the center of gravity position signal to the controller;

[0008] The counterweight mechanism includes a solid-liquid mixed counterweight box located at the rear of the turntable, and a first liquid counterweight box and a second liquid counterweight box located on both sides of the turntable and in front of the solid-liquid mixed counterweight box. The solid-liquid mixed counterweight box is connected to one port of the servo motor pump, and the first liquid counterweight box and the second liquid counterweight box are connected to the other port of the servo motor pump.

[0009] The controller is connected to the center of gravity detector and the servo motor pump respectively, and is used to receive the center of gravity position signal and control the servo motor pump to turn so that the liquid in the first liquid counterweight box and / or the second liquid counterweight box flows to the solid-liquid mixed counterweight box, or so that the liquid in the solid-liquid mixed counterweight box flows to the first liquid counterweight box and / or the second liquid counterweight box.

[0010] Furthermore, the first liquid counterweight tank is connected to the servo motor pump via a first solenoid valve, and the second liquid counterweight tank is connected to the servo motor pump via a second solenoid valve. The first and second solenoid valves are respectively connected to the controller.

[0011] Furthermore, the center of gravity detector includes a first pressure sensor, a second pressure sensor, a third pressure sensor, and a fourth pressure sensor disposed between the turntable and the slewing support.

[0012] Furthermore, the solid-liquid mixed counterweight box includes a solid counterweight and a third liquid counterweight box mounted on the solid counterweight.

[0013] Furthermore, the first liquid counterweight box, the second liquid counterweight box, and the third liquid counterweight box are equipped with corrugated anti-sway plates, and the first liquid counterweight box, the second liquid counterweight box, and the third liquid counterweight box are equipped with built-in respirators.

[0014] In a second aspect, an excavator is provided, comprising the center of gravity control system described in any one of the first aspects.

[0015] Thirdly, a method for controlling the center of gravity of the excavator described in the second aspect is provided, comprising:

[0016] Get the center of gravity adjustment mode;

[0017] When the acquired center of gravity adjustment mode is manual mode, based on the user-set work instructions and database, the servo motor pump is controlled to rotate, adjusting the liquid flow in the first liquid counterweight tank and / or the second liquid counterweight tank to the solid-liquid mixing counterweight tank, or adjusting the liquid flow in the solid-liquid mixing counterweight tank to the first liquid counterweight tank and / or the second liquid counterweight tank; after the adjustment is completed, it is determined whether the current center of gravity position from the center of gravity detector is within the error allowable range compared with the center of gravity position required in the database. If it exceeds the error allowable range, the adjustment is performed again until the center of gravity position is within the error allowable range compared with the center of gravity position required in the database, the manual mode is completed, the servo motor pump is turned off, and normal construction begins;

[0018] When the obtained center of gravity adjustment mode is automatic, the database is used to determine whether the center of gravity position meets the requirements. If it does not meet the requirements, the servo motor pump is controlled to turn based on the current center of gravity position from the center of gravity detector, and the liquid flow in the first liquid counterweight tank and / or the second liquid counterweight tank is adjusted to the solid-liquid mixing counterweight tank, or the liquid flow in the solid-liquid mixing counterweight tank is adjusted to the first liquid counterweight tank and / or the second liquid counterweight tank. After the adjustment is completed, normal construction begins.

[0019] Furthermore, it also includes: after normal construction is completed, restoring the counterweights of the first liquid counterweight box, the second liquid counterweight box, and the solid-liquid mixed counterweight box to their initial state and performing automatic calibration.

[0020] Furthermore, the adjusted liquid weight is achieved by controlling the liquid flow time, and the relationship between the liquid weight and the liquid flow time is as follows:

[0021] m=ρ*V=ρ*η*Q*t

[0022] Where m is the liquid weight, ρ is the liquid density, V is the liquid volume, η is the efficiency (η = 0.9-0.98), Q is the flow rate of the servo motor pump, and t is the liquid flow time.

[0023] Furthermore, the center of gravity detector calculates the center of gravity position using the pressure values ​​detected by the first, second, third, and fourth pressure sensors located between the turntable and the slewing support, as well as the torque balance. The calculation method includes:

[0024] Using the center of rotation as the origin, the direction pointing from the origin to the back of the turntable as the x-axis, and the direction perpendicular to the x-axis as the y-axis, let the coordinates of the first pressure sensor be (-A, B) and it detects force F1; the coordinates of the second pressure sensor be (A, B) and it detects force F2; the coordinates of the third pressure sensor be (-A, -B) and it detects force F3; and the coordinates of the fourth pressure sensor be (A, -B) and it detects force F4. Then the coordinates of the center of gravity (x, y) satisfy:

[0025] (-A+x)*F1+(Ax)*F2+(-A+x)*F3+(Ax)*F4=0;

[0026] (By)*F1+(By)*F2+(-B+y)*F3+(-B+y)*F4=0.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] (1) The center of gravity control system provided by the present invention includes a turntable, a center of gravity detector, a servo motor pump, a counterweight mechanism and a controller. The controller is connected to the center of gravity detector and the servo motor pump respectively, and is used to receive the center of gravity position signal from the center of gravity detector and control the servo motor pump to turn so that the liquid in the first liquid counterweight box and / or the second liquid counterweight box flows to the solid-liquid mixed counterweight box, or so that the liquid in the solid-liquid mixed counterweight box flows to the first liquid counterweight box and / or the second liquid counterweight box. The center of gravity is adjusted by using liquid. The system has a simple structure, is easy to operate and has strong adaptability.

[0029] (2) The excavator center of gravity control method provided by the present invention realizes manual and automatic adjustment of the center of gravity of the whole machine through a brand-new control logic. It can realize the center of gravity detection function of the excavator, realize the center of gravity self-adjustment function with one click, realize the counterweight mass adjustment of various sites and working conditions, realize the center of gravity self-adaptation function, and can more effectively improve the stability of the whole machine. With the help of the center of gravity dynamic balance excitation technology, it can conveniently realize the multi-working condition adaptability of the excavator and realize the multi-purpose use of one machine. It can realize the consistent stability of the whole machine when the excavator is in different working conditions or equipped with different tools, and provide a brand-new design idea for the stability design of excavators. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the installation structure of the center of gravity control system provided in an embodiment of the present invention;

[0031] Figure 2 This is a control logic diagram of the excavator center of gravity control method provided in the embodiments of the present invention;

[0032] The following are labeled in the diagram: 1. Turntable; 2. Center of gravity detector; 3. Controller; 4. Servo motor pump; 5. First solenoid valve; 6. Second solenoid valve; 7. Second liquid counterweight tank; 8. First liquid counterweight tank; 9. Solid-liquid mixed counterweight tank; 10. Anti-sway plate; 11. Breather; 12. First pressure sensor; 13. Rotary support; 14. Rotation center; 15. Second pressure sensor; 16. Third pressure sensor; 17. Fourth pressure sensor. Detailed Implementation

[0033] 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.

[0034] Example 1

[0035] like Figure 1 As shown, this embodiment provides a center of gravity control system, including a turntable 1, a center of gravity detector 2, a servo motor pump 4, a counterweight mechanism, and a controller 3.

[0036] Turntable 1 is connected to slewing support 13 via slewing center 14. Center of gravity detector 2 is located between turntable 1 and slewing support 13. Center of gravity detector 2 includes a first pressure sensor 12, a second pressure sensor 15, a third pressure sensor 16, and a fourth pressure sensor 17 located between turntable 1 and slewing support 13. Center of gravity detector 2 is a device that calculates the center of gravity position based on the pressure values ​​detected by the four pressure sensors and the torque balance. That is, it is used to monitor the center of gravity position and transmit the center of gravity position signal to controller 3.

[0037] The counterweight mechanism includes a solid-liquid mixed counterweight box 9 located at the rear of the turntable 1, and a first liquid counterweight box 8 and a second liquid counterweight box 7 located on both sides of the turntable 1 and in front of the solid-liquid mixed counterweight box 9. The solid-liquid mixed counterweight box 9 is connected to one port of the servo motor pump 4, and the first liquid counterweight box 8 and the second liquid counterweight box 7 are connected to the other port of the servo motor pump 4. Specifically, the first liquid counterweight box 8 is connected to the servo motor pump 4 through a first solenoid valve 5, and the second liquid counterweight box 7 is connected to the servo motor pump 4 through a second solenoid valve 6.

[0038] The solid-liquid mixed counterweight box 9 includes a solid counterweight and a third liquid counterweight box mounted on the solid counterweight. The first liquid counterweight box 8, the second liquid counterweight box 7, and the third liquid counterweight box are filled with a high-density heavy salt solution, characterized by high solubility and high density in water, with a maximum solubility of up to 65%, at which point the density of the heavy salt solution is approximately 2 kg / m³. 3 This heavy salt solution also exhibits low-temperature resistance, remaining unfrozen and crystallized at around -40°C. Using this heavy salt solution as a substitute for solid counterweights provides excellent flow and mixing characteristics, offers significant weight capacity, and is well-suited to low-temperature operating conditions, making it a perfect replacement for solid counterweights. To reduce vibrations caused by vehicle body swaying, the first liquid counterweight tank 8, the second liquid counterweight tank 7, and the third liquid counterweight tank are equipped with corrugated anti-sloshing plates 10. To ensure smooth liquid flow, the first liquid counterweight tank 8, the second liquid counterweight tank 7, and the third liquid counterweight tank are equipped with built-in breathers 11, which also serve the function of adding liquid.

[0039] The controller 3 is connected to the center of gravity detector 2, the servo motor pump 4, the first solenoid valve 5, and the second solenoid valve 6 respectively. It is used to receive the center of gravity position signal and control the direction of the servo motor pump 4 and the opening and closing of the first solenoid valve 5 and the second solenoid valve 6, so that the liquid in the first liquid counterweight tank 8 and / or the second liquid counterweight tank 7 flows to the solid-liquid mixing counterweight tank 9, or so the liquid in the solid-liquid mixing counterweight tank 9 flows to the first liquid counterweight tank 8 and / or the second liquid counterweight tank 7.

[0040] During design and installation, a dedicated cavity is designed under the left and right frames of the machine to house the first and second rotomolded liquid counterweight boxes 8 and 2. A third liquid counterweight box is added to the existing solid counterweights, forming a solid-liquid hybrid counterweight box 9, thus arranging the counterweight mechanism. Then, the servo motor pump 4, the first solenoid valve 5, and the second solenoid valve 6 are placed in the lower part of the pump chamber, and the pipelines are connected to the upper part of each liquid counterweight box, thus completing the overall installation and arrangement of the center of gravity control system.

[0041] Example 2

[0042] This embodiment provides an excavator, including the center of gravity control system described in Embodiment 1.

[0043] Example 3

[0044] like Figure 1 and Figure 2 As shown, this embodiment provides a method for controlling the center of gravity of an excavator as described in Embodiment 2, the steps of which are as follows:

[0045] Step 1: The user selects the center of gravity adjustment mode, either manual or automatic; and when the vehicle starts, the vehicle body counterweight mechanism is in its initial state (factory state).

[0046] Step 2: Adjust the center of gravity.

[0047] (1) The center of gravity adjustment mode is manual.

[0048] Step 2.1.1: The controller 3 automatically calibrates the initial position based on the database using the center of gravity detector 2.

[0049] Step 2.1.2: The user sets the working instructions, such as standard mode, multiple tools, multiple working conditions, center of gravity adjustment, etc.

[0050] Step 2.1.3: According to the work instructions set by the user and the machine tools or working conditions calculated in the database, the controller 3 sends action signals to the servo motor pump 4, the first solenoid valve 5, and the second solenoid valve 6 to adjust the liquid in the first liquid counterweight tank 8, the second liquid counterweight tank 7, and the solid-liquid mixed counterweight tank 9 to the corresponding counterweight tank.

[0051] When the vehicle's center of gravity needs to be moved backward, the weight of the solid-liquid mixture counterweight box 9 needs to be increased. At this time, the controller 3 controls the servo motor pump 4 to run in the forward direction, the controller 3 controls the first solenoid valve 5 to open and controls the first liquid counterweight box 8 to output liquid weight according to the time value set in the system database. Once the requirements are met, it can be closed. The controller 3 controls the second solenoid valve 6 to open and controls the second liquid counterweight box 7 to output liquid weight according to the time value set in the system database. Once the requirements are met, it can be closed.

[0052] When it is necessary to move the vehicle's center of gravity forward or adjust it left or right, the weight of the first liquid counterweight tank 8 and / or the second liquid counterweight tank 7 needs to be increased. At this time, the controller 3 controls the servo motor pump 4 to run in reverse, the controller 3 controls the first solenoid valve 5 to open and controls the liquid weight input to the first liquid counterweight tank 8 according to the time value set in the system database, and can close it after the requirements are met; the controller 3 controls the second solenoid valve 6 to open and controls the liquid weight input to the second liquid counterweight tank 7 according to the time value set in the system database, and can close it after the requirements are met.

[0053] Step 2.1.4: After the adjustment is completed, the controller 3 determines whether the current center of gravity position from the center of gravity detector 2 is within the allowable error range compared with the required center of gravity position in the database. If it exceeds the allowable error range, the adjustment is performed again until the center of gravity position is within the allowable error range compared with the required center of gravity position in the database. The manual mode is then completed, and the adjustment data is recorded as the basis data for subsequent mode optimization.

[0054] Step 2.1.5: Turn off the servo motor pump 4, the first solenoid valve 5, and the second solenoid valve 6, and proceed with normal construction.

[0055] (2) The center of gravity adjustment mode is automatic.

[0056] Step 2.2.1 After normal construction, the controller 3 automatically calibrates the initial position according to the database through the center of gravity detector 2.

[0057] Step 2.2.2: When the controller 3 determines from the database that the center of gravity position provided by the center of gravity detector 2 does not meet the system requirements, it sends action signals to the servo motor pump 4, the first solenoid valve 5, and the second solenoid valve 6 based on the current center of gravity position from the center of gravity detector 2 and by calling the algorithm data in the database. This adjusts the liquid in the first liquid counterweight tank 8, the second liquid counterweight tank 7, and the solid-liquid mixed counterweight tank 9 to the corresponding counterweight tanks.

[0058] Step 2.2.3: After the adjustment is completed, normal construction begins. At the same time, the data in the center of gravity detector 2 is checked, the difference between the data provided by the database and the actual adjustment data is analyzed and recorded in the database. When the data reaches a certain level, the algorithm will be optimized to improve the accuracy of the algorithm, thereby enabling precise real-time adjustment of the center of gravity position.

[0059] Step 3: After normal construction is completed, if the user removes the additional equipment or cancels the center of gravity adjustment, the counterweights of the first liquid counterweight box 8, the second liquid counterweight box 7 and the solid-liquid mixed counterweight box 9 need to be restored to their initial state and automatically calibrated.

[0060] Specifically, in step 2 above, the adjusted liquid weight is achieved by controlling the liquid flow time, and the relationship between the liquid weight and the liquid flow time is as follows:

[0061] m=ρ*V=ρ*η*Q*t

[0062] Where m is the weight of the liquid, in kg; ρ is the density of the liquid, in kg / m³. 3 V is the liquid volume in L; η is the efficiency, η = 0.9-0.98; Q is the flow rate of the servo motor pump, a constant value in L / S; t is the liquid flow time in s.

[0063] Specifically, in step 2 above, the center of gravity detector calculates the center of gravity position using the pressure values ​​detected by the first, second, third, and fourth pressure sensors located between the turntable and the slewing support, as well as the torque balance. The calculation method includes:

[0064] Using the center of rotation as the origin, the direction pointing from the origin to the back of the turntable as the x-axis, and the direction perpendicular to the x-axis as the y-axis, let the coordinates of the first pressure sensor be (-A, B) and it detects force F1; the coordinates of the second pressure sensor be (A, B) and it detects force F2; the coordinates of the third pressure sensor be (-A, -B) and it detects force F3; and the coordinates of the fourth pressure sensor be (A, -B) and it detects force F4. Then the coordinates of the center of gravity (x, y) satisfy:

[0065] (-A+x)*F1+(Ax)*F2+(-A+x)*F3+(Ax)*F4=0;

[0066] (By)*F1+(By)*F2+(-B+y)*F3+(-B+y)*F4=0.

[0067] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application 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.

[0068] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. 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... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0069] 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.

[0070] 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.

[0071] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A center of gravity control system, characterized in that, Includes a turntable, a center of gravity detector, a servo motor pump, a counterweight mechanism, and a controller; The turntable is connected to the slewing support through the slewing center, and the center of gravity detector is located between the turntable and the slewing support to monitor the center of gravity position and transmit the center of gravity position signal to the controller; The counterweight mechanism includes a solid-liquid hybrid counterweight box located at the rear of the turntable, and a first liquid counterweight box and a second liquid counterweight box located on both sides of the turntable and in front of the solid-liquid hybrid counterweight box. The solid-liquid hybrid counterweight box is connected to one port of the servo motor pump, and the first and second liquid counterweight boxes are connected to the other port of the servo motor pump. The solid-liquid hybrid counterweight box includes a solid counterweight and a third liquid counterweight box mounted on the solid counterweight. The first, second, and third liquid counterweight boxes are equipped with corrugated anti-sloshing plates, and the first, second, and third liquid counterweight boxes are equipped with built-in respirators. The controller is connected to the center of gravity detector and the servo motor pump respectively, and is used to receive the center of gravity position signal and control the servo motor pump to turn so that the liquid in the first liquid counterweight box and / or the second liquid counterweight box flows to the solid-liquid mixture counterweight box, or so that the liquid in the solid-liquid mixture counterweight box flows to the first liquid counterweight box and / or the second liquid counterweight box. The control method of the center of gravity control system includes: Get the center of gravity adjustment mode; When the acquired center of gravity adjustment mode is manual mode, based on the user-set work instructions and database, the servo motor pump is controlled to rotate, adjusting the liquid flow in the first liquid counterweight tank and / or the second liquid counterweight tank to the solid-liquid mixing counterweight tank, or adjusting the liquid flow in the solid-liquid mixing counterweight tank to the first liquid counterweight tank and / or the second liquid counterweight tank; after the adjustment is completed, it is determined whether the current center of gravity position from the center of gravity detector is within the error allowable range compared with the center of gravity position required in the database. If it exceeds the error allowable range, the adjustment is performed again until the center of gravity position is within the error allowable range compared with the center of gravity position required in the database, the manual mode is completed, the servo motor pump is turned off, and normal construction begins; When the obtained center of gravity adjustment mode is automatic, the database is used to determine whether the center of gravity position meets the requirements. If it does not meet the requirements, the servo motor pump is controlled to turn based on the current center of gravity position from the center of gravity detector, and the liquid flow in the first liquid counterweight tank and / or the second liquid counterweight tank is adjusted to the solid-liquid mixing counterweight tank, or the liquid flow in the solid-liquid mixing counterweight tank is adjusted to the first liquid counterweight tank and / or the second liquid counterweight tank. After the adjustment is completed, normal construction begins.

2. The center of gravity control system according to claim 1, characterized in that, The first liquid counterweight tank is connected to the servo motor pump via a first solenoid valve, and the second liquid counterweight tank is connected to the servo motor pump via a second solenoid valve. The first and second solenoid valves are respectively connected to the controller.

3. The center of gravity control system according to claim 1, characterized in that, The center of gravity detector includes a first pressure sensor, a second pressure sensor, a third pressure sensor, and a fourth pressure sensor located between the turntable and the slewing support.

4. An excavator, characterized in that, Includes the center of gravity control system as described in any one of claims 1 to 3.

5. A method for controlling the center of gravity of an excavator as described in claim 4, characterized in that, include: Get the center of gravity adjustment mode; When the acquired center of gravity adjustment mode is manual mode, based on the user-set work instructions and database, the servo motor pump is controlled to rotate, adjusting the liquid flow in the first liquid counterweight tank and / or the second liquid counterweight tank to the solid-liquid mixing counterweight tank, or adjusting the liquid flow in the solid-liquid mixing counterweight tank to the first liquid counterweight tank and / or the second liquid counterweight tank; after the adjustment is completed, it is determined whether the current center of gravity position from the center of gravity detector is within the error allowable range compared with the center of gravity position required in the database. If it exceeds the error allowable range, the adjustment is performed again until the center of gravity position is within the error allowable range compared with the center of gravity position required in the database, the manual mode is completed, the servo motor pump is turned off, and normal construction begins; When the obtained center of gravity adjustment mode is automatic, the database is used to determine whether the center of gravity position meets the requirements. If it does not meet the requirements, the servo motor pump is controlled to turn based on the current center of gravity position from the center of gravity detector, and the liquid flow in the first liquid counterweight tank and / or the second liquid counterweight tank is adjusted to the solid-liquid mixing counterweight tank, or the liquid flow in the solid-liquid mixing counterweight tank is adjusted to the first liquid counterweight tank and / or the second liquid counterweight tank. After the adjustment is completed, normal construction begins.

6. The excavator center of gravity control method according to claim 5, characterized in that, Also includes: After normal construction is completed, the counterweights of the first liquid counterweight box, the second liquid counterweight box, and the solid-liquid mixture counterweight box are restored to their initial state and automatically calibrated.

7. The excavator center of gravity control method according to claim 5, characterized in that, The adjusted liquid weight is achieved by controlling the liquid flow time, and the relationship between the liquid weight and the liquid flow time is as follows: m=ρ*V=ρ*η*Q*t; Where m is the liquid weight, ρ is the liquid density, V is the liquid volume, η is the efficiency (η=0.9-0.98), Q is the flow rate of the servo motor pump, and t is the liquid flow time.

8. The excavator center of gravity control method according to claim 5, characterized in that, The center of gravity detector calculates the position of the center of gravity using pressure values ​​detected by a first pressure sensor, a second pressure sensor, a third pressure sensor, and a fourth pressure sensor located between the turntable and the slewing support, as well as torque balance. The calculation method includes: Using the center of rotation as the origin, the direction pointing from the origin to the back of the turntable as the x-axis, and the direction perpendicular to the x-axis as the y-axis, let the coordinates of the first pressure sensor be (-A, B) and it detects force F1; the coordinates of the second pressure sensor be (A, B) and it detects force F2; the coordinates of the third pressure sensor be (-A, -B) and it detects force F3; and the coordinates of the fourth pressure sensor be (A, -B) and it detects force F4. Then the coordinates of the center of gravity (x, y) satisfy: (-A+x)*F1+(Ax)*F2+(-A+x)*F3+(Ax)*F4=0; (By)*F1+(By)*F2+(-B+y)*F3+(-B+y)*F4=0.

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