Mass compensation device, magnetic suspension balance assembly and control method thereof

Abstract

The invention relates to the technical field of sample measurement, particularly provides a mass compensation device, a magnetic suspension balance assembly and a control method thereof, and aims to solve the problem that the measurement accuracy is influenced by the nonlinear change of response characteristics of an existing magnetic suspension balance under different loads. In order to achieve the purpose, the mass compensation device comprises a balance weight bearing structure connected with a weighing structure of a balance body, a first balance weight, a second balance weight different from the first balance weight in mass and a balance weight switching device, the balance weight switching device is arranged to be capable of selectively placing one of the first balance weight and the second balance weight on the balance weight bearing structure, and the balance weight switching device is arranged to be capable of selectively placing the other one of the first balance weight and the second balance weight on the balance weight bearing structure. Therefore, the load of the balance body is stabilized in a set range. The mass compensation device can greatly reduce errors caused by nonlinear response of the balance body under different loads, so that the accuracy of a measurement result of the balance body is improved.

Description

Technical Field

[0001] The invention relates to the technical field of sample measurement, and specifically provides a mass compensation device, a magnetic suspension balance component and a control method thereof. Background Art

[0002] A magnetic levitation balance is a precision measuring instrument that uses magnetic field force to measure the mass of an object and its mass change. A magnetic levitation balance usually includes a magnetic levitation coupling structure and a balance body. The magnetic levitation coupling structure includes a permanent magnet and an electromagnet. The electromagnet is connected to the weighing structure of the balance body, and the measuring sample is connected to the permanent magnet. When weighing, the electromagnet is energized, and the magnetic field generated by it interacts with the permanent magnet, so that the permanent magnet and the measuring sample connected to it are in a free suspension state, and the weighing result is obtained through the reading of the balance body. Since the permanent magnet and the measuring sample are not in contact with the electromagnet and the balance body, the slight influence of friction and wear caused by mechanical contact on high-precision weighing is avoided. It can also be used for high-precision mass measurement in special environments such as vacuum, high temperature and high pressure, and special gases.

[0003] Since the response characteristics of the balance body under different loads are not completely linear, there is an error between the weighing value and the actual load. For example, when the balance body is tared and weighed with a sample for measurement, the load of the balance body differs greatly, so the nonlinear error it produces is relatively large, which in turn affects the accuracy of the weighing result. Frequent switching between two loads with a large difference in weight, one heavy and one light, is not a common working condition for a microbalance with a precision of micrograms, so the impact of nonlinear errors on measurement results is difficult to ignore.

[0004] Accordingly, the art needs a mass compensation device, a magnetic suspension balance assembly and a control method thereof to solve the above problems. Summary of the invention

[0005] The present invention aims to solve the problem that the response characteristics of the existing magnetic suspension balance change nonlinearly under different loads, thereby affecting the measurement accuracy.

[0006] In a first aspect, the present invention provides a mass compensation device, comprising: a counterweight supporting structure, the counterweight supporting structure being connected to the weighing structure of a balance body; a first counterweight; a second counterweight, the mass of the second counterweight being different from the mass of the first counterweight; and a counterweight switching device, the counterweight switching device being configured to selectively place one of the first counterweight and the second counterweight on the counterweight supporting structure so that the load of the balance body is stabilized within a set range.

[0007] When the above technical solution is adopted, since the counterweight switching device can selectively place the first counterweight or the second counterweight of different masses on the counterweight supporting structure, the counterweight switching device places the heavier counterweight on the counterweight supporting structure when the weighing is at the zero position, and when the weighing work position where the sample for measurement is placed, the counterweight switching device places the lighter counterweight on the counterweight supporting structure, so that the two loads of the balance body are close to or the same, and the load of the balance body can be stabilized within the set range, so as to greatly reduce the error caused by the nonlinear response of the balance body under different loads, thereby improving the accuracy of the measurement result of the balance body.

[0008] In a specific embodiment of the above-mentioned mass compensation device, the counterweight switching device includes: a first moving structure, the first moving structure is configured to be able to drive the first counterweight to move to a first placement position placed on the counterweight supporting structure and a first lifting position that does not contact the counterweight supporting structure, and when the first counterweight is located at the first placement position, the first moving structure does not contact the first counterweight; a second moving structure, the second moving structure is configured to be able to drive the second counterweight to move to a second placement position placed on the counterweight supporting structure and a second lifting position that does not contact the counterweight supporting structure, and when the second counterweight is located at the second placement position, the second moving structure does not contact the second counterweight.

[0009] When the above technical solution is adopted, the first moving structure can drive the first counterweight to move to the first placement position and the first lifting position, and the second moving structure can drive the second counterweight to move to the second placement position and the second lifting position, thereby realizing separate control of the first counterweight and the second counterweight, and being able to selectively place the first counterweight and the second counterweight on the counterweight supporting structure; since the first counterweight does not contact the first moving structure when placed on the counterweight supporting structure, the first counterweight can be completely placed on the counterweight supporting structure, and the accuracy of the measurement result of the balance body will not be affected by the contact with the first moving structure; and since the second counterweight does not contact the second moving structure when placed on the counterweight supporting structure, the second counterweight can be completely placed on the counterweight supporting structure, and the accuracy of the measurement result of the balance body will not be affected by the contact with the second moving structure; in summary, the setting of the first moving structure and the second moving structure can greatly reduce the error caused by the nonlinear response characteristics of the balance body under different loads, while further improving the accuracy of the measurement result.

[0010] In a specific embodiment of the above-mentioned mass compensation device, a first protrusion and a second protrusion are respectively provided on the two end surfaces of the first counterweight; the first movable structure includes a first bracket and a second bracket, and a first connecting block connected between the first bracket and the second bracket, the first bracket is configured to be able to rotate in a vertical plane, a first mounting hole is provided on the first bracket, and a second mounting hole is provided on the second bracket, the first counterweight is installed between the first bracket and the second bracket, and the first protrusion and the second protrusion are respectively penetrated into the first mounting hole and the second mounting hole, the diameter of the first mounting hole is larger than the diameter of the first protrusion, the diameter of the second mounting hole is larger than the diameter of the second protrusion, the distance between the first bracket and the second bracket is larger than the distance between the two end surfaces of the first counterweight, and when the first movable structure drives the first counterweight to rotate to the first placement position, the bottom wall heights of the first mounting hole and the second mounting hole are different, so that when the first counterweight is horizontally placed on the counterweight supporting structure, it does not contact the first bracket and the second bracket.

[0011] When the above technical solution is adopted, since the first counterweight is installed between the first bracket and the second bracket, and the first protrusion and the second protrusion are respectively inserted into the first mounting hole and the second mounting hole, the first counterweight is overlapped on the bottom wall of the first mounting hole and the second mounting hole under the action of gravity; and since the bottom wall heights of the first mounting hole and the second mounting hole are different when the first moving structure drives the first counterweight to rotate to the first placement position, the first counterweight is placed at an angle when the first counterweight is not placed on the counterweight supporting structure; as the first counterweight is placed on the counterweight supporting structure, the first counterweight changes from an inclined state to a horizontal state, and since the diameter of the first mounting hole is larger than the first protrusion The diameter of the first bracket is larger than the diameter of the second mounting hole, and the diameter of the second mounting hole is larger than the diameter of the second protrusion. Therefore, the first protrusion and the second protrusion can move with the first counterweight to a position where they do not contact the hole walls of the first mounting hole and the second mounting hole. At the same time, since the distance between the first bracket and the second bracket is larger than the distance between the two end surfaces of the first counterweight, the two end surfaces of the first counterweight can move to a position where they do not contact the side surfaces of the first bracket and the second bracket, thereby achieving the first counterweight being placed horizontally on the counterweight supporting structure without contacting the first bracket and the second bracket, thereby avoiding affecting the accuracy of the measurement result of the balance body due to the first counterweight contacting the first moving structure when placed on the counterweight supporting structure.

[0012] In a specific implementation of the mass compensation device, the first movable structure further includes a first steering gear and a first rotating arm, and the first rotating arm is transmission-connected to the first steering gear and fixedly connected to the first bracket.

[0013] When the above technical solution is adopted, the first servo drives the first rotating arm to rotate, which in turn drives the first bracket to rotate, and finally drives the first counterweight to rotate. Since the first servo can accurately control the rotation angle and rotation speed of the output shaft, the speed at which the first counterweight is placed on the counterweight supporting structure can be accurately controlled, thereby avoiding an instantaneous large load on the balance body due to the first counterweight moving too fast and being placed on the counterweight supporting structure too fast, thereby protecting the balance body and avoiding affecting the accuracy of the measurement result of the balance body.

[0014] In a specific embodiment of the above-mentioned mass compensation device, the counterweight switching device also includes a first limiting structure, which is arranged below the first rotating arm. When the first counterweight is located at the first placement position, the first rotating arm abuts against the first limiting structure to limit the downward movement of the first rotating arm.

[0015] When the above technical solution is adopted, by setting the first limiting structure, it is possible to prevent the first rotating arm and the first counterweight and other structures connected thereto from continuing to move downward when the first counterweight is placed on the counterweight supporting structure, thereby preventing forces other than the first counterweight from acting on the counterweight supporting structure, which would affect the measurement results of the balance body or even cause damage to the balance body.

[0016] In a specific implementation of the mass compensation device, the motor of the first steering gear is a unidirectional capacitor motor or a three-phase induction motor.

[0017] When the above technical solution is adopted, since the unidirectional capacitor motor does not generate a magnetic field and the magnetic field strength of the three-phase induction motor is zero, the motor of the first servo gear adopts a unidirectional capacitor motor or a three-phase induction motor to avoid generating a magnetic field that interferes with the measurement of the balance body, thereby ensuring the accuracy of the measurement.

[0018] In a specific embodiment of the above-mentioned mass compensation device, a third protrusion and a fourth protrusion are respectively provided on the two end surfaces of the second counterweight; the second movable structure includes a third bracket and a fourth bracket, and a second connecting block connected between the third bracket and the fourth bracket, the third bracket is configured to be able to rotate in a vertical plane, the third bracket is provided with a third mounting hole, and the fourth bracket is provided with a fourth mounting hole, the second counterweight is installed between the third bracket and the fourth bracket, and the third protrusion and the fourth protrusion are respectively penetrated in the third mounting hole and the fourth mounting hole, the diameter of the third mounting hole is greater than the diameter of the third protrusion, the diameter of the fourth mounting hole is greater than the diameter of the fourth protrusion, the distance between the third bracket and the fourth bracket is greater than the distance between the two end surfaces of the second counterweight, and when the second movable structure drives the second counterweight to rotate to the second placement position, the bottom wall heights of the third mounting hole and the fourth mounting hole are different, so that when the second counterweight is horizontally placed on the counterweight supporting structure, it does not contact the third bracket and the fourth bracket.

[0019] When the above technical solution is adopted, since the second counterweight is installed between the third bracket and the fourth bracket, and the third protrusion and the fourth protrusion are respectively inserted into the third mounting hole and the fourth mounting hole, the second counterweight is overlapped on the bottom wall of the third mounting hole and the fourth mounting hole under the action of gravity; and since the bottom wall heights of the third mounting hole and the fourth mounting hole are different when the second moving structure drives the second counterweight to rotate to the second placement position, the second counterweight is placed at an angle when the second counterweight is not placed on the counterweight supporting structure; as the second counterweight is placed on the counterweight supporting structure, the second counterweight changes from an inclined state to a horizontal state, and since the diameter of the third mounting hole is larger than that of the third protrusion The diameter of the fourth mounting hole is larger than the diameter of the fourth protrusion, so the third protrusion and the fourth protrusion can move with the second counterweight to a position where they do not contact the hole walls of the third mounting hole and the fourth mounting hole. At the same time, since the distance between the third bracket and the fourth bracket is larger than the distance between the two end surfaces of the second counterweight, the two end surfaces of the second counterweight can move to a position where they do not contact the side surfaces of the third bracket and the fourth bracket, thereby achieving the second counterweight being placed horizontally on the counterweight supporting structure without contacting the third bracket and the fourth bracket, thereby avoiding the accuracy of the measurement result of the balance body being affected by the contact between the second counterweight and the second moving structure when the second counterweight is placed on the counterweight supporting structure.

[0020] In a specific implementation of the mass compensation device, the second movable structure further includes a second steering gear and a second rotating arm, and the second rotating arm is transmission-connected to the second steering gear and fixedly connected to the third bracket.

[0021] When the above technical solution is adopted, the second servo drives the second rotating arm to rotate, which in turn drives the third bracket to rotate, and finally drives the second counterweight to rotate. Since the second servo can accurately control the rotation angle and rotation speed of the output shaft, the speed at which the second counterweight is placed on the counterweight supporting structure can be accurately controlled, thereby avoiding an instantaneous large load on the balance body due to the second counterweight moving too fast and being placed on the counterweight supporting structure too fast, thereby protecting the balance body and avoiding affecting the accuracy of the measurement result of the balance body.

[0022] In a specific embodiment of the above-mentioned mass compensation device, the counterweight switching device also includes a second limiting structure, which is arranged below the second rotating arm. When the second counterweight is located at the second placement position, the second rotating arm abuts against the second limiting structure to limit the downward movement of the second rotating arm.

[0023] When the above technical solution is adopted, by setting the second limiting structure, when the second counterweight is placed on the counterweight supporting structure, the second rotating arm and the second counterweight and other structures connected thereto can be prevented from continuing to move downward, thereby preventing forces other than the second counterweight from acting on the counterweight supporting structure, which would affect the measurement results of the balance body or even cause damage to the balance body.

[0024] In a specific implementation of the mass compensation device, the motor of the second steering gear is a unidirectional capacitor motor or a three-phase induction motor.

[0025] When the above technical solution is adopted, since the unidirectional capacitor motor does not generate a magnetic field and the magnetic field strength of the three-phase induction motor is zero, the motor of the second servo adopts a unidirectional capacitor motor or a three-phase induction motor to avoid generating a magnetic field that interferes with the measurement of the balance body, thereby ensuring the accuracy of the measurement.

[0026] In a specific embodiment of the above-mentioned mass compensation device, the volume of the first counterweight is the same as the volume of the second counterweight; and / or the mass compensation device also includes a base, the base is arranged above the balance body, and the counterweight switching device is installed on the base.

[0027] In the case of adopting the above technical solution, since the volume of the first counterweight is the same as that of the second counterweight, the air buoyancy of the first counterweight and the second counterweight is the same, so that when switching the first counterweight and the second counterweight, no additional error is introduced, further ensuring the accuracy of the measurement of the balance body. The base is used to facilitate the installation of the counterweight switching device.

[0028] In a second aspect, the present invention further provides a magnetic suspension balance assembly, wherein the magnetic suspension balance assembly comprises a magnetic suspension balance and a mass compensation device, wherein the magnetic suspension balance comprises a balance body.

[0029] When the above technical solution is adopted, the magnetic levitation balance assembly can stabilize the load of the balance body of the magnetic levitation balance within a set range by setting a mass compensation device, so as to greatly reduce the error caused by the nonlinear response characteristics of the balance body under different loads, thereby improving the accuracy of the measurement results of the balance body.

[0030] In a third aspect, the present invention also provides a control method for a magnetic levitation balance assembly, the magnetic levitation balance assembly comprising a magnetic levitation balance and a mass compensation device, the magnetic levitation balance comprising a balance body; the mass compensation device comprising: a counterweight supporting structure, the counterweight supporting structure being connected to the weighing structure of the balance body; a first counterweight; a second counterweight, the mass of the second counterweight being greater than the mass of the first counterweight; a counterweight switching device, the counterweight switching device being configured to selectively place one of the first counterweight and the second counterweight on the counterweight supporting structure so that the load of the balance body is stabilized within a set range; the control method comprising: at the weighing zero position, controlling the counterweight switching device to place the second counterweight on the counterweight supporting structure; at the weighing working position, controlling the counterweight switching device to place the first counterweight on the counterweight supporting structure.

[0031] When the above technical solution is adopted, the counterweight switching device is controlled to place the heavier second counterweight on the counterweight supporting structure when the weighing is at the zero position, and the counterweight switching device is controlled to place the lighter first counterweight on the counterweight supporting structure when the weighing working position where the sample for measurement is placed is placed, so that the two loads of the balance body of the magnetic suspension balance are close to or the same, and the load of the balance body can be stabilized within the set range, so as to greatly reduce the error caused by the nonlinear response characteristics of the balance body under different loads, thereby improving the accuracy of the measurement result of the balance body.

[0032] In a specific embodiment of the control method of the above-mentioned magnetic suspension balance assembly, the counterweight switching device includes: a first moving structure, the first moving structure is configured to be able to drive the first counterweight to move to a first placement position placed on the counterweight supporting structure and a first lifting position that is not in contact with the counterweight supporting structure, the first moving structure includes a first bracket, a second bracket, a first steering gear, a first rotating arm, and a first connecting block connected between the first bracket and the second bracket, the first counterweight is installed between the first bracket and the second bracket, the first rotating arm is connected to the first steering gear by transmission, and is fixedly connected to the first bracket; a second moving structure, the second moving structure is configured to be able to drive the second counterweight to move to a second placement position placed on the counterweight supporting structure and a second lifting position that is not in contact with the counterweight supporting structure, the second moving structure includes a third bracket, a fourth bracket, a second steering gear, a second rotating arm, and a second connecting block connected between the third bracket and the fourth bracket, the second counterweight is installed between the third bracket and the fourth bracket, the second rotating arm is connected to the second steering gear by transmission, and is fixedly connected to the third bracket fixed connection; the mass compensation device also includes: a first angle detection device, the first angle detection device is used to detect a first angle value of a first angle between the first rotating arm and the horizontal plane; a second angle detection device, the second angle detection device is used to detect a second angle value of a second angle between the second rotating arm and the horizontal plane; wherein the first angle is the angle of the first rotating arm within the moving range between the first placement position and the first lifting position, and the second angle is the angle of the second rotating arm within the moving range between the second placement position and the second lifting position, and the first angle value and the second angle value are both greater than or equal to 0° and less than 180°; before the step of "controlling the counterweight switching device to place the first counterweight on the counterweight supporting structure", the control method also includes: obtaining the first angle value and the second angle value; the step of "controlling the counterweight switching device to place the first counterweight on the counterweight supporting structure" further includes: based on the first angle value and the second angle value, controlling the first steering gear and / or the second steering gear to rotate so as to place the first counterweight on the counterweight supporting structure.

[0033] When the above technical solution is adopted, since the positions of the first counterweight and the second counterweight can be determined according to the first angle value and the second angle value, the rotation of the first servo and / or the second servo is controlled based on the first angle value and the second angle value, so that contact and collision between the first counterweight and the second counterweight can be avoided during the placement of the first counterweight.

[0034] In a specific implementation of the control method of the above-mentioned magnetic levitation balance assembly, the step of "based on the first angle value and the second angle value, controlling the first servo and / or the second servo to rotate so as to place the first counterweight on the counterweight supporting structure" further includes: if the second angle value is greater than or equal to a preset first angle threshold, and the first angle value is not equal to 0°, controlling the first servo to rotate so that the first angle value is reduced to 0°.

[0035] When the above technical solution is adopted, when the second angle value is greater than or equal to the first angle threshold, the second counterweight is not on the counterweight supporting structure and is far away from the counterweight supporting structure, and the first counterweight will not contact or collide with the second counterweight during rotation. When the first angle value is not equal to 0°, the first counterweight is not placed on the counterweight supporting structure. In this case, the first servo is controlled to rotate so that when the first angle value is reduced to 0°, the first counterweight can be smoothly placed on the counterweight supporting structure.

[0036] In a specific implementation of the control method of the above-mentioned magnetic levitation balance assembly, the step of "if the second angle value is greater than or equal to a preset first angle threshold, and the first angle value is not equal to 0°, then controlling the first steering gear to rotate so that the first angle value is reduced to 0°" further includes: if the second angle value is greater than or equal to the first angle threshold, and the first angle value is greater than the preset second angle threshold, then controlling the first steering gear to rotate at a preset first rate value so that the first angle value is reduced to the second angle threshold; controlling the first steering gear to rotate at a preset second rate value so that the first angle value is reduced to 0°; wherein the second rate value is less than the first rate value; and / or if the second angle value is greater than or equal to the first angle threshold, and the first angle value is greater than 0° and less than or equal to the preset second angle threshold, then controlling the first steering gear to rotate at a preset second rate value so that the first angle value is reduced to 0°.

[0037] When the above technical solution is adopted, when the first angle value is greater than the preset second angle threshold, the first angle value is larger, and the first counterweight is farther away from the counterweight supporting structure. At this time, the first servo is controlled to rotate at a larger first rate value, so that the first counterweight can rotate smoothly at a relatively fast speed, ensuring the rotation efficiency while avoiding the influence of the accuracy of the measurement result of the balance body due to the first counterweight moving speed being too fast; when the first angle value is greater than 0° and less than or equal to the second angle threshold, the first angle value is smaller, and the first counterweight is closer to the counterweight supporting structure. At this time, the first servo is controlled to rotate at a smaller second rate value to reduce the first angle value by 0°, so that the first counterweight can be slowly and steadily placed on the counterweight supporting structure, avoiding the instantaneous large load on the balance body due to the first counterweight being placed on the counterweight supporting structure too fast, protecting the balance body while avoiding affecting the accuracy of the measurement result of the balance body.

[0038] In a specific implementation of the control method of the above-mentioned magnetic levitation balance assembly, the step of "based on the first angle value and the second angle value, controlling the first servo and / or the second servo to rotate so as to place the first counterweight on the counterweight supporting structure" further includes: if the second angle value is less than a preset first angle threshold, controlling the second servo to rotate so that the second angle value increases to be greater than or equal to the first angle threshold; if the first angle value is not equal to 0°, controlling the first servo to rotate so that the first angle value decreases to 0°.

[0039] When the above technical solution is adopted, when the second angle value is less than the first angle threshold, the second counterweight may be located on the counterweight supporting structure or close to the counterweight supporting structure, and the first counterweight may contact and collide with the second counterweight during the process of rotating to the counterweight supporting structure. Therefore, the second servo is controlled to rotate so that the second angle increases to be greater than or equal to the first angle threshold, and then the first servo is controlled to rotate. This can avoid the first counterweight and the second counterweight being placed on the counterweight supporting structure at the same time, and can also avoid the first counterweight contacting and colliding with the second counterweight during the process of rotating to the counterweight supporting structure.

[0040] Compared with the prior art, the beneficial effect of the mass compensation device provided by the present invention is that: since the counterweight switching device can selectively place the first counterweight or the second counterweight of different masses on the counterweight supporting structure, when the weighing is at zero position, the counterweight switching device places the heavier counterweight on the counterweight supporting structure, and when the weighing working position where the sample for measurement is placed is placed, the counterweight switching device places the lighter counterweight on the counterweight supporting structure, so that the two loads of the balance body are close or the same, and then the load of the balance body can be stabilized within a set range, so as to greatly reduce the error caused by the nonlinear response of the balance body under different loads, thereby improving the accuracy of the measurement result of the balance body. The beneficial effect of the magnetic suspension balance assembly provided by the present invention is that the mass compensation device is applied to the magnetic suspension balance, and can stabilize the load of the balance body of the magnetic suspension balance within a set range, so as to greatly reduce the error caused by the nonlinear response characteristics of the balance body under different loads, thereby improving the accuracy of the measurement result of the balance body. The beneficial effect of the control method of the magnetic levitation balance assembly provided by the present invention is: by controlling the counterweight switching device to place the heavier second counterweight on the counterweight supporting structure when in the weighing zero position, and controlling the counterweight switching device to place the lighter first counterweight on the counterweight supporting structure when in the weighing working position, the two loads of the balance body of the magnetic levitation balance are close to or the same, and the load of the balance body can be stabilized within a set range, so as to greatly reduce the error caused by the nonlinear response characteristics of the balance body under different loads, thereby improving the accuracy of the measurement result of the balance body. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings, in which:

[0042] Figure 1 It is a schematic diagram of the overall structure of the magnetic suspension balance assembly of the present invention;

[0043] Figure 2 It is a structural schematic diagram of the mass compensation device and the balance body of the present invention;

[0044] Figure 3 It is a schematic diagram of the overall structure of the mass compensation device of the present invention;

[0045] Figure 4 is a usage state diagram of the first mobile structure and the second mobile structure of the present invention;

[0046] Figure 5 is another use state diagram of the first mobile structure and the second mobile structure of the present invention;

[0047] Figure 6 It is a flow chart of the main steps of the control method of the magnetic suspension balance assembly of the present invention;

[0048] Figure 7 It is a detailed step flow chart of an implementation method of the control method of the magnetic suspension balance assembly of the present invention;

[0049] Figure 8 It is a detailed step flow chart of another embodiment of the control method of the magnetic suspension balance assembly of the present invention;

[0050] Reference numerals:

[0051] 1-mass compensation device, 2-balance body, 3-electromagnet, 4-permanent magnet, 11-counterweight supporting structure, 12-first counterweight, 13-second counterweight, 14-counterweight switching device, 15-base, 111-tray, 112-bracket, 121-first protrusion, 122-second protrusion, 131-third protrusion, 132-fourth protrusion, 141-first moving structure, 142-second moving structure, 1411-first steering gear, 1412-first rotating arm, 1413-first bracket, 1414-second bracket, 1415-first connecting block, 1421-second steering gear, 1422-second rotating arm, 1423-third bracket, 1424-fourth bracket, 1425-second connecting block. DETAILED DESCRIPTION

[0052] Some embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not used to limit the scope of protection of the present invention. Those skilled in the art can make adjustments to them as needed to adapt to specific application scenarios.

[0053] It should be noted that, in the description of the present invention, the terms "center", "upper", "lower", "left", "right", "front", "back", "top", "bottom", "vertical", "horizontal", "inside", "outside" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the relevant devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, in the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0054] In addition, it should be noted that in the description of the present invention, ordinal numbers such as "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. In addition, in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0055] Based on the problem pointed out in the background technology that the response characteristics of the magnetic levitation balance under different loads in the prior art change nonlinearly, thereby affecting the measurement accuracy, the present invention aims to selectively place a first counterweight or a second counterweight with different masses on the counterweight supporting structure through a mass compensation device, so as to stabilize the load of the balance body of the magnetic levitation balance within a set range, so as to greatly reduce the error caused by the nonlinear response of the balance body under different loads, thereby improving the accuracy of the measurement result of the balance body.

[0056] See first Figure 1 , Figure 1 The overall structure of the magnetic suspension balance assembly of the present invention is shown. Figure 1 As shown, the magnetic suspension balance assembly of the present invention includes a magnetic suspension balance and a mass compensation device 1, the magnetic suspension balance includes a magnetic suspension coupling structure and a balance body 2, the magnetic suspension coupling structure includes a permanent magnet 4 and an electromagnet 3, the permanent magnet 4 is arranged below the electromagnet 3, the electromagnet 3 is connected to the weighing structure of the balance body 2, and the measurement sample is connected to the permanent magnet 4. When weighing, the electromagnet 3 is energized, and the magnetic field generated by it interacts with the permanent magnet 4. By adjusting the current of the electromagnet 3, the permanent magnet 4 and the measurement sample connected thereto are in a free suspension state, and the weighing measurement result is obtained through the reading of the balance body 2.

[0057] It should be noted that the magnetic suspension balance is usually used to measure the adsorption performance of the sample to the gas and the density change of the measured gas. During the measurement, the sample for measurement is connected to the permanent magnet 4 and placed in a test environment filled with the measured gas. When measuring the adsorption performance of the sample to the gas, the adsorption performance of the sample to the measured gas is determined by detecting the mass change of the sample; when measuring the density change of the gas, the buoyancy change of the sample is determined by detecting the weight change of the sample, and then the density of the gas to be tested is determined. Since the mass change in the above measurement process is very small, a very small measurement error will have a greater impact on the measurement result. It is necessary to compensate for the error caused by the nonlinear response characteristics of the balance body 2 under different loads to greatly reduce the error and improve the measurement accuracy.

[0058] See below Figure 2 , Figure 2 The schematic diagram of the structure of the mass compensation device and the balance body of the present invention is shown. Figure 2 As shown, the mass compensation device 1 of the present invention includes a counterweight supporting structure 11, a first counterweight 12, a second counterweight 13 and a counterweight switching device 14, the counterweight supporting structure 11 is connected to the weighing structure of the balance body 2; the mass of the second counterweight 13 is greater than the mass of the first counterweight 12; the counterweight switching device 14 is configured to selectively place one of the first counterweight 12 and the second counterweight 13 on the counterweight supporting structure 11, so that the load of the balance body 2 is stabilized within a set range. Since the counterweight switching device 14 can selectively place the first counterweight 12 or the second counterweight 13 of different masses on the counterweight supporting structure 11, the counterweight switching device 14 places the heavier counterweight on the counterweight supporting structure 11 when the weighing is at the zero position, and when the weighing work position where the sample for measurement is placed is at the weighing work position, the counterweight switching device 14 places the lighter counterweight on the counterweight supporting structure 11, so that the two loads of the balance body 2 are close to or the same, and the load of the balance body 2 can be stabilized within the set range, so as to greatly reduce the error caused by the nonlinear response of the balance body 2 under different loads, thereby improving the accuracy of the measurement result of the balance body 2.

[0059] For example, when the mass of the sample is 60g, the mass of the first counterweight 12 is 22g, the mass of the second counterweight 13 is 82g, and the weight of the permanent magnet 4 is 5g. When in the weighing working position, the first counterweight 12 is placed on the counterweight supporting structure 11, and the reading of the balance body 2 is 60+22+5=87g. When in the weighing zero position, the second counterweight 13 is placed on the counterweight supporting structure 11, and the reading of the balance body 2 is 82+5=87g. The two readings are the same, which greatly reduces the nonlinear error of the balance body 2 and improves the measurement accuracy. It should be noted that during the measurement experiment of the sample by the magnetic levitation balance, the mass change of the sample is small. For example, when the sample is subjected to adsorption measurement, the amount of gas adsorbed by the sample is less than or equal to 2‰ of the mass of the sample itself, and when measuring the gas density, the change in gas buoyancy of the sample is less than or equal to 0.032‰ of the sample. Therefore, the mass change of the sample is very small, and the balance body can still be ensured to operate within a range close to a linear response.

[0060] Optionally, the volume of the first counterweight 12 can be the same as that of the second counterweight 13. Since the volume of the first counterweight 12 is the same as that of the second counterweight 13, the air buoyancy of the first counterweight 12 and the second counterweight 13 is the same, so that when switching the first counterweight 12 and the second counterweight 13, no additional error is introduced, further ensuring the accuracy of the measurement of the balance body 2. In addition, the material of the first counterweight 12 can be titanium, and the material of the second counterweight 13 can be tantalum. Since the density of titanium and tantalum is quite different, a large mass difference can be satisfied when the volume is the same, and titanium and tantalum are highly stable, hard and easy to process, and can change in quality over a long period of use. In addition, the material of the first counterweight 12 can also be a material with a lower density such as magnesium-lithium alloy and aluminum, and the second counterweight 13 can also be a material with a higher density such as gold, platinum, iridium, tungsten, etc.

[0061] Optionally, the mass compensation device 1 may further include a base 15, which is disposed above the balance body 2. The counterweight switching device 14 is installed on the base 15 through a mounting bracket. The base 15 is used to facilitate the installation of the counterweight switching device 14. The base 15 can be directly installed on the outer casing of the balance body 2.

[0062] It should be noted that the mass compensation device 1 can be applied to a magnetic suspension balance, other high-precision weighing equipment, or ordinary weighing equipment, which is not specifically limited here.

[0063] See below Figure 2-Figure 5 , Figure 3 The overall structure of the mass compensation device of the present invention is shown. Figure 4 The figure shows a usage state of the first moving structure and the second moving structure of the present invention. Figure 5Another use state of the first moving structure and the second moving structure of the present invention is shown. Figure 2-Figure 5 As shown, as a possible embodiment, the counterweight switching device 14 includes a first movable structure 141 and a second movable structure 142, and the first movable structure 141 is configured to be able to drive the first counterweight 12 to move to a first placement position placed on the counterweight supporting structure 11 and a first lifting position that does not contact the counterweight supporting structure 11, and when the first counterweight 12 is located at the first placement position, the first movable structure 141 does not contact the first counterweight 12; the second movable structure 142 is configured to be able to drive the second counterweight 13 to move to a second placement position placed on the counterweight supporting structure 11 and a second lifting position that does not contact the counterweight supporting structure 11, and when the second counterweight 13 is located at the second placement position, the second movable structure 142 does not contact the second counterweight 13. The first counterweight 12 and the second counterweight 13 are controlled separately, and the first counterweight 12 and the second counterweight 13 can be selectively placed on the counterweight supporting structure 11; since the first counterweight 12 does not contact the first moving structure 141 when placed on the counterweight supporting structure 11, the first counterweight 12 can be completely placed on the counterweight supporting structure 11, and the accuracy of the measurement result of the balance body 2 will not be affected by the contact with the first moving structure 141; and since the second counterweight 13 does not contact the second moving structure 142 when placed on the counterweight supporting structure 11, the second counterweight 13 can be completely placed on the counterweight supporting structure 11, and the accuracy of the measurement result of the balance body 2 will not be affected by the contact with the second moving structure 142; in summary, through the arrangement of the first moving structure 141 and the second moving structure 142, the error caused by the nonlinear response characteristics of the balance body 2 under different loads can be greatly reduced, while further improving the accuracy of the measurement result.

[0064] Specifically, the first two end surfaces of the first counterweight 12 are respectively provided with a first protrusion 121 and a second protrusion 122; the first moving structure 141 includes a first steering gear 1411, a first rotating arm 1412, a first bracket 1413 and a second bracket 1414, and a first connecting block 1415 connected between the first bracket 1413 and the second bracket 1414, the first rotating arm 1412 is transmission-connected to the first steering gear 1411, and is fixedly connected to the first bracket 1413, so that the first bracket 1413 can rotate in a vertical plane, the first bracket 1413 is provided with a first mounting hole, the second bracket 1414 is provided with a second mounting hole, and the first counterweight 12 is installed on the first bracket 1 413 and the second bracket 1414, and the first protrusion 121 and the second protrusion 122 are respectively penetrated into the first mounting hole and the second mounting hole, the diameter of the first mounting hole is larger than the diameter of the first protrusion 121, the diameter of the second mounting hole is larger than the diameter of the second protrusion 122, the distance between the first bracket 1413 and the second bracket 1414 is larger than the distance between the two end surfaces of the first counterweight 12, and when the first moving structure 141 drives the first counterweight 12 to rotate to the first placement position, the bottom wall heights of the first mounting hole and the second mounting hole are different, so that when the first counterweight 12 is horizontally placed on the counterweight supporting structure 11, it does not contact the first bracket 1413 and the second bracket 1414. Since the first counterweight 12 is installed between the first bracket 1413 and the second bracket 1414, and the first protrusion 121 and the second protrusion 122 are respectively arranged in the first mounting hole and the second mounting hole, the first counterweight 12 is overlapped on the bottom wall of the first mounting hole and the second mounting hole under the action of gravity; and since the bottom wall heights of the first mounting hole and the second mounting hole are different when the first moving structure 141 drives the first counterweight 12 to rotate to the first placement position, the first counterweight 12 is placed at an angle when it is not placed on the counterweight supporting structure 11. The state at this time is as shown in FIG. Figure 4 As the first counterweight 12 is placed on the counterweight supporting structure 11, the first counterweight 12 changes from an inclined state to a horizontal state, and the state at this time is as shown Figure 5As shown, since the diameter of the first mounting hole is larger than the diameter of the first protrusion 121, and the diameter of the second mounting hole is larger than the diameter of the second protrusion 122, the first protrusion 121 and the second protrusion 122 can move with the first counterweight 12 to a position where they do not contact the hole walls of the first mounting hole and the second mounting hole. At the same time, since the distance between the first bracket 1413 and the second bracket 1414 is larger than the distance between the two end surfaces of the first counterweight 12, the two end surfaces of the first counterweight 12 can move to a position where they do not contact the side surfaces of the first bracket 1413 and the second bracket 1414, thereby achieving the goal of placing the first counterweight 12 horizontally on the counterweight supporting structure 11 without contacting the first bracket 1413 and the second bracket 1414, thereby avoiding the accuracy of the measurement result of the balance body 2 being affected by the contact between the first counterweight 12 and the first moving structure 141 when the first counterweight 12 is placed on the counterweight supporting structure 11.

[0065] Specifically, a third protrusion 131 and a fourth protrusion 132 are respectively provided on the two end surfaces of the second counterweight 13; the second mobile structure 142 and the first mobile structure 141 are arranged on both sides of the counterweight supporting structure 11, the second mobile structure 142 includes a second steering gear 1421, a second rotating arm 1422, a third bracket 1423 and a fourth bracket 1424, and a second connecting block 1425 connected between the third bracket 1423 and the fourth bracket 1424, the second rotating arm 1422 is transmission-connected to the second steering gear 1421, and is fixedly connected to the third bracket 1423, so that the third bracket 1423 can rotate in a vertical plane, the third bracket 1423 is provided with a third mounting hole, and the fourth bracket 1424 is provided with a fourth mounting hole. The second counterweight 13 is installed between the third bracket 1423 and the fourth bracket 1424, and the third protrusion 131 and the fourth protrusion 132 are respectively inserted into the third mounting hole and the fourth mounting hole, the diameter of the third mounting hole is larger than the diameter of the third protrusion 131, the diameter of the fourth mounting hole is larger than the diameter of the fourth protrusion 132, the distance between the third bracket 1423 and the fourth bracket 1424 is larger than the distance between the two end surfaces of the second counterweight 13, and when the second moving structure 142 drives the second counterweight 13 to rotate to the second placement position, the bottom wall heights of the third mounting hole and the fourth mounting hole are different, so that when the second counterweight 13 is horizontally placed on the counterweight supporting structure 11, it does not contact the third bracket 1423 and the fourth bracket 1424. Since the second counterweight 13 is installed between the third bracket 1423 and the fourth bracket 1424, the third protrusion 131 and the fourth protrusion 132 are respectively arranged in the third mounting hole and the fourth mounting hole, the second counterweight 13 is overlapped on the bottom wall of the third mounting hole and the fourth mounting hole under the action of gravity; and since the bottom wall heights of the third mounting hole and the fourth mounting hole are different when the second moving structure 142 drives the second counterweight 13 to rotate to the second placement position, the second counterweight 13 is tilted when it is not placed on the counterweight supporting structure 11. The state at this time is as shown in FIG. Figure 4As the second counterweight 13 is placed on the counterweight supporting structure 11, the second counterweight 13 changes from an inclined state to a horizontal state, and the state at this time is as shown Figure 5 As shown, since the diameter of the third mounting hole is greater than the diameter of the third protrusion 131, and the diameter of the fourth mounting hole is greater than the diameter of the fourth protrusion 132, the third protrusion 131 and the fourth protrusion 132 can move with the second counterweight 13 to a position where they do not contact the hole walls of the third mounting hole and the fourth mounting hole. At the same time, since the distance between the third bracket 1423 and the fourth bracket 1424 is greater than the distance between the two end surfaces of the second counterweight 13, the two end surfaces of the second counterweight 13 can move to a position where they do not contact the side surfaces of the third bracket 1423 and the fourth bracket 1424, thereby achieving the goal of placing the second counterweight 13 horizontally on the counterweight supporting structure 11 without contacting the third bracket 1423 and the fourth bracket 1424, thereby avoiding the accuracy of the measurement result of the balance body 2 being affected by the contact between the second counterweight 13 and the second moving structure 142 when the second counterweight 13 is placed on the counterweight supporting structure 11.

[0066] Optionally, the motor of the first servo 1411 and the motor of the second servo 1421 can be a unidirectional capacitor motor or a three-phase induction motor. Since the unidirectional capacitor motor does not generate a magnetic field and the magnetic field strength of the three-phase induction motor is zero, the use of a unidirectional capacitor motor or a three-phase induction motor can avoid the generation of a magnetic field that interferes with the measurement of the balance body 2, thereby ensuring the accuracy of the measurement. It should be noted that the first servo 1411 and the second servo 1421 can also use other motors, and the first rotating arm 1412 and the second rotating arm 1422 can also be directly driven to rotate by a driving device such as a motor or a pneumatic motor, as long as the first bracket 1413 and the third bracket 1423 can be driven to rotate in a vertical plane. Those skilled in the art can make adjustments as needed without departing from the principles of the present invention and falling within the protection scope of the present invention.

[0067] See also Figure 2 and Figure 3As a possible implementation, the counterweight switching device 14 also includes a first limiting structure and a second limiting structure. The first limiting structure is arranged below the rotating arm of the first connecting block 1415. When the first counterweight 12 is located at the first placement position, the rotating arm of the first connecting block 1415 abuts against the first limiting structure to limit the downward movement of the first rotating arm 1412; the second limiting structure is arranged below the rotating arm of the second connecting block 1425. When the second counterweight 13 is located at the second placement position, the second rotating arm 1422 abuts against the second limiting structure to limit the downward movement of the second rotating arm 1422. By setting the first limiting structure and the second limiting structure, when the first counterweight 12 or the second counterweight 13 is placed on the counterweight supporting structure 11, the first rotating arm 1412 and the first counterweight 12 and other structures connected thereto or the second rotating arm 1422 and the second counterweight 13 and other structures connected thereto can be prevented from continuing to move downward, thereby preventing forces other than the first counterweight 12 or the second counterweight 13 from acting on the counterweight supporting structure 11, which would affect the measurement results of the balance body 2 or even cause damage to the balance body 2.

[0068] Specifically, the first limiting structure and the second limiting structure can be bolts threadedly connected to the base 15, and the height of the bolts can be adjusted by screwing the bolts, and the heads of the bolts are used to limit the first rotating arm 1412 or the second rotating arm 1422; the first limiting structure and the second limiting structure can also include a cylinder connected to the base 15, the cylinder rod of the cylinder is connected to the limiting block, and the height of the limiting block is adjusted by the cylinder, and the limiting block is used to limit the first rotating arm 1412 or the second rotating arm 1422.

[0069] Specifically, the counterweight supporting structure 11 may include a tray 111 and a bracket 112, wherein the bracket 112 is connected to the tray 111, and the bracket 112 is provided with at least two brackets, and the top of the bracket 112 is provided with a groove. Since the first counterweight 12 and the second counterweight 13 are usually cylindrical, the circumferential surfaces of the first counterweight 12 and the second counterweight 13 are in contact with the groove, so that the first counterweight 12 and the second counterweight 13 can be stably placed on the bracket 112; wherein, the shape of the groove can be an arc, or a triangle or a trapezoid, as long as the first counterweight 12 and the second counterweight 13 can be fixed after being placed on the groove. In the case where the first counterweight 12 and the second counterweight 13 need to be placed horizontally on the counterweight supporting structure 11, the shape of the groove of each bracket 112 and the height of the bottom wall and the side wall are the same.

[0070] Specifically, the mass compensation device 1 also includes a first angle detection device and a second angle detection device, the first angle detection device is used to detect a first angle value of a first angle between the first rotating arm 1412 and the horizontal plane, and the second angle detection device is used to detect a second angle value of a second angle between the second rotating arm 1422 and the horizontal plane, and the first angle detection device and the second angle detection device can be a laser interferometer, a three-coordinate measuring machine, etc.; wherein, the first angle is the angle of the first rotating arm 1412 within the moving range between the first placement position and the first lifting position, and the second angle is the angle of the second rotating arm 1422 within the moving range between the second placement position and the second lifting position, and the first angle value and the second angle value are both greater than or equal to 0° and less than 180°.

[0071] The present invention also provides a control method for a magnetic suspension balance assembly, see Figure 6 , which shows the main steps of the control method of the magnetic suspension balance assembly of the present invention, such as Figure 6 As shown, the control method in this embodiment mainly includes the following steps S101 to S102:

[0072] Step S101: When the weighing is at zero position, the counterweight switching device is controlled to place the second counterweight on the counterweight supporting structure.

[0073] The weighing zero position refers to the weighing mode when no sample for measurement is connected to the permanent magnet. The weighing zero position can be determined by manually selecting or inputting the weighing zero position mode on the magnetic suspension balance or the mobile terminal. When the controller receives the signal of the weighing zero position mode, it is determined that the magnetic suspension balance is at the weighing zero position. The position sensor can also be set to detect the position of the permanent magnet. When the position of the permanent magnet is detected to be within the preset weighing zero position range, it is determined that the magnetic suspension balance is at the weighing zero position.

[0074] Step S102: At the weighing working position, control the counterweight switching device to place the first counterweight on the counterweight supporting structure.

[0075] The weighing working position refers to the weighing mode when a sample for measurement is connected to the permanent magnet. The weighing working position can be determined by manually selecting or inputting the weighing working position mode on the magnetic suspension balance or the mobile terminal. When the controller receives the signal of the weighing working position mode, it is determined that the magnetic suspension balance is in the weighing working position. The position sensor can also be set to detect the position of the permanent magnet. When the position of the permanent magnet is detected to be within the preset weighing working position range, it is determined that the magnetic suspension balance is in the weighing working position.

[0076] Through the control method of step S101 to step S102, when the weighing is in the zero position, the counterweight switching device is controlled to place the heavier second counterweight on the counterweight supporting structure, and when the weighing is in the working position, the counterweight switching device is controlled to place the lighter first counterweight on the counterweight supporting structure, so that the two loads of the balance body of the magnetic suspension balance are close to or the same, and the load of the balance body can be stabilized within the set range, so as to greatly reduce the error caused by the nonlinear response characteristics of the balance body under different loads, thereby improving the accuracy of the measurement result of the balance body.

[0077] It should be noted that the order of step S101 and step S102 is not restrictive, and the order of step S101 and step S102 can be adjusted as needed.

[0078] See below Figure 7 , which shows the detailed steps of an implementation method of the control method of the magnetic suspension balance assembly of the present invention, specifically comprising the following steps:

[0079] Step S201: At the weighing working position, obtain a second angle value.

[0080] Step S202: Determine whether the second angle value is greater than or equal to the first angle threshold value. If the determination result is yes, execute step S203; if the determination result is no, execute step S204.

[0081] Since when the second angle value is less than the first angle threshold, the second counterweight may be located on the counterweight supporting structure or close to the counterweight supporting structure, and the first counterweight may come into contact and collide with the second counterweight during the process of rotating to the counterweight supporting structure, so the second angle value and the first angle threshold are judged. Among them, the first angle threshold value can be set to different values ​​according to the length of the first rotating arm and the second rotating arm and the distance between them, as long as the second angle value is greater than or equal to the first angle threshold, the first counterweight will not come into contact and collide with the second counterweight during the rotation process. Exemplarily, the first angle threshold can be set in the range of 50° to 90°, and can be selected as 50°.

[0082] Step S203: Obtain the first angle value. After step S203, execute step S205.

[0083] Step S204: Control the second steering engine to rotate at a third speed value to increase the second angle value. After step S204, execute step S201.

[0084] When the second angle value is less than the first angle threshold, the second servo is controlled to rotate at a third rate value so that the second angle value increases to be greater than or equal to the first angle threshold, which can avoid the first counterweight and the second counterweight being placed on the counterweight support structure at the same time, and can also avoid the first counterweight from contacting and colliding with the second counterweight during the process of rotating to the counterweight support structure. Controlling the second servo to rotate at the third rate value can ensure that the second counterweight can rotate at a relatively fast but not too fast speed, so that the second counterweight can rotate smoothly, avoiding affecting the accuracy of the measurement results. Among them, the third rate value can be set to different values ​​as needed, or it can be a relatively fixed value; illustratively, the third rate value can be set in the range of 1° / 30 milliseconds to 1° / 10 milliseconds, preferably 1° / 20 milliseconds. Among them, the maximum angle after the second angle value is increased is less than 180°, and can be selected as 90°.

[0085] Step S205: Determine whether the first angle value is greater than the second angle threshold value. If the determination result is yes, execute step S206; if the determination result is no, execute step S207.

[0086] Step S206: Control the first steering engine to rotate at a first speed value so as to reduce the first angle value. After step S206, execute step S203.

[0087] When the first angle value is greater than the first angle threshold, the first angle value is large, and the first counterweight is far from the counterweight supporting structure. At this time, the first servo is controlled to rotate at a larger first rate value to reduce the first angle value, which can ensure that the first counterweight can rotate at a relatively fast but not too fast speed, so that the first counterweight can rotate smoothly to avoid affecting the accuracy of the measurement result. Among them, the first rate value can be set to different values ​​as needed, or it can be a relatively fixed value; illustratively, the first rate value can be set in the range of 1° / 30 milliseconds to 1° / 10 milliseconds, preferably 1° / 20 milliseconds.

[0088] Step S207: Determine whether the first angle value is greater than 0° and less than or equal to the second angle threshold. If the determination result is yes, execute step S208; if the determination result is no, execute step S209.

[0089] Step S208: Control the first steering engine to rotate at a second speed value so as to reduce the first angle value. After step S208, execute step S209.

[0090] When the first angle value is greater than 0° and less than or equal to the second angle threshold, the first angle value is small, and the first counterweight is close to the counterweight supporting structure. At this time, the first servo is controlled to rotate at a smaller second rate value to reduce the first angle value, which can ensure that the first counterweight can be placed slowly and steadily on the counterweight supporting structure, avoiding the instantaneous large load on the balance body caused by the first counterweight being placed on the counterweight supporting structure too quickly, protecting the balance body while avoiding affecting the accuracy of the measurement results of the balance body. Among them, the second rate value can be set to different values ​​as needed, or it can be a relatively fixed value; illustratively, the first rate value can be set in the range of 1° / 50 milliseconds to 1° / 70 milliseconds, preferably 1° / 60 milliseconds.

[0091] Step S209: Determine whether the first angle value is equal to 0°. If the determination result is yes, execute step S210; if the determination result is no, execute step S208.

[0092] When the first angle value is equal to 0°, the first counterweight is placed on the counterweight supporting structure.

[0093] Step S210: Sending action completion information.

[0094] Through the control method of steps S201 to S210, the first counterweight can be placed on the counterweight supporting structure stably and smoothly at the weighing workstation.

[0095] See below Figure 8 , which shows the detailed steps of another embodiment of the control method of the magnetic suspension balance assembly of the present invention, specifically comprising the following steps:

[0096] Step S301: When weighing at zero position, obtain a first angle value.

[0097] Step S302: Determine whether the first angle value is greater than or equal to the third angle threshold value. If the determination result is yes, execute step S303; if the determination result is no, execute step S304.

[0098] Since when the first angle value is less than the third angle threshold, the first counterweight may be located on the counterweight supporting structure or close to the counterweight supporting structure, and the second counterweight will contact and collide with the first counterweight during the process of rotating to the counterweight supporting structure, so the size of the first angle value and the third angle threshold is judged. Among them, the size of the third angle threshold can be set to different values ​​according to the length of the first rotating arm and the second rotating arm and the distance between them. As long as the first angle value is greater than or equal to the third angle threshold, the second counterweight will not contact and collide with the first counterweight during the rotation process. Exemplarily, the first angle threshold can be set in the range of 50° to 90°, and can be selected as 50°. The third angle threshold can be the same as the first angle threshold, or it can be different.

[0099] Step S303: Obtain the second angle value. After step S303, execute step S305.

[0100] Step S304: Control the first steering engine to rotate at a third speed value to increase the first angle value. After step S304, execute step S301.

[0101] When the first angle value is less than the third angle threshold, the first steering gear is controlled to rotate at the third rate value so that the first angle value increases to be greater than or equal to the third angle threshold, which can avoid the first counterweight and the second counterweight being placed on the counterweight support structure at the same time, and can also avoid the second counterweight from contacting and colliding with the first counterweight during the process of rotating to the counterweight support structure. Controlling the first steering gear to rotate at the third rate value can ensure that the first counterweight can rotate at a relatively fast but not too fast speed, so that the first counterweight can rotate smoothly, avoiding affecting the accuracy of the measurement result. Wherein, the maximum angle after the first angle value is increased is less than 180°, and can be selected as 90°.

[0102] Step S305: Determine whether the second angle value is greater than the second angle threshold. If the determination result is yes, execute step S306; if the determination result is no, execute step S307.

[0103] Step S306: Control the second steering engine to rotate at the first speed value so as to reduce the second angle value. After step S306, execute step S303.

[0104] When the second angle value is greater than the first angle threshold, the second angle value is larger, and the second counterweight is farther away from the counterweight supporting structure. At this time, the second servo is controlled to rotate at a larger first rate value to reduce the second angle value, thereby ensuring that the second counterweight can rotate at a relatively fast speed but not too fast, so that the second counterweight can rotate smoothly and avoid affecting the accuracy of the measurement results.

[0105] Step S307: Determine whether the second angle value is greater than 0° and less than or equal to the second angle threshold. If the determination result is yes, execute step S308; if the determination result is no, execute step S309.

[0106] Step S308: Control the second steering engine to rotate at a second speed value so as to reduce the second angle value. After step S308, execute step S309.

[0107] When the second angle value is greater than 0° and less than or equal to the second angle threshold, the second angle value is small, and the second counterweight is close to the counterweight supporting structure. At this time, the second servo is controlled to rotate at a smaller second rate value to reduce the second angle value, thereby ensuring that the second counterweight can be placed slowly and steadily on the counterweight supporting structure, avoiding the instantaneous large load on the balance body due to the second counterweight being placed on the counterweight supporting structure too quickly, thereby protecting the balance body and avoiding affecting the accuracy of the measurement results of the balance body.

[0108] Step S309: Determine whether the second angle value is equal to 0°. If the determination result is yes, execute step S310; if the determination result is no, execute step S308.

[0109] When the second angle value is equal to 0°, the second counterweight is placed on the counterweight supporting structure.

[0110] Step S310: Sending action completion information.

[0111] Through the control method of step S301 to step S310, the second counterweight can be placed on the counterweight supporting structure stably and smoothly when the weighing is at zero position.

[0112] It should be noted that the above-mentioned embodiments are only used to illustrate the principles of the present invention and are not intended to limit the scope of protection of the present invention. Without departing from the principles of the present invention, those skilled in the art can adjust the above-mentioned embodiments so that the present invention can be applied to more specific application scenarios.

[0113] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A mass compensation device, characterized in that: The mass compensation device comprises: A counterweight supporting structure (11), wherein the counterweight supporting structure (11) is connected to the weighing structure of the balance body (2); a first counterweight (12); a second counterweight (13), the mass of the second counterweight (13) being different from the mass of the first counterweight (12); A counterweight switching device (14), wherein the counterweight switching device (14) is configured to selectively place one of the first counterweight (12) and the second counterweight (13) on the counterweight supporting structure (11), so as to stabilize the load of the balance body (2) within a set range.

2. The mass compensation device according to claim 1, characterized in that: The counterweight switching device (14) comprises: a first moving structure (141), the first moving structure (141) being configured to drive the first counterweight (12) to move to a first placement position placed on the counterweight supporting structure (11) and a first lifting position not in contact with the counterweight supporting structure (11), and when the first counterweight (12) is located at the first placement position, the first moving structure (141) is not in contact with the first counterweight (12); A second movable structure (142), wherein the second movable structure (142) is configured to drive the second counterweight (13) to move to a second placement position placed on the counterweight supporting structure (11) and a second lifting position not in contact with the counterweight supporting structure (11), and when the second counterweight (13) is located at the second placement position, the second movable structure (142) is not in contact with the second counterweight (13).

3. The mass compensation device according to claim 2, characterized in that: A first protrusion (121) and a second protrusion (122) are respectively provided on both end surfaces of the first counterweight (12); The first movable structure (141) comprises a first bracket (1413) and a second bracket (1414), and a first connecting block (1415) connected between the first bracket (1413) and the second bracket (1414); the first bracket (1413) is configured to be rotatable in a vertical plane; a first mounting hole is provided on the first bracket (1413); a second mounting hole is provided on the second bracket (1414); the first counterweight (12) is installed between the first bracket (1413) and the second bracket (1414); and the first protrusion (121) and the second protrusion (122) are respectively inserted into the first mounting hole and the second mounting hole. In the mounting hole, the diameter of the first mounting hole is larger than the diameter of the first protrusion (121), the diameter of the second mounting hole is larger than the diameter of the second protrusion (122), the distance between the first bracket (1413) and the second bracket (1414) is larger than the distance between the two end surfaces of the first counterweight (12), and when the first movable structure (141) drives the first counterweight (12) to rotate to the first placement position, the bottom wall heights of the first mounting hole and the second mounting hole are different, so that when the first counterweight (12) is horizontally placed on the counterweight supporting structure (11), it does not contact the first bracket (1413) and the second bracket (1414).

4. The mass compensation device according to claim 3, characterized in that: The first movable structure (141) further comprises a first steering gear (1411) and a first rotating arm (1412); the first rotating arm (1412) is transmission-connected to the first steering gear (1411) and fixedly connected to the first bracket (1413).

5. The mass compensation device according to claim 4, characterized in that: The counterweight switching device (14) further comprises a first limiting structure, which is arranged below the first rotating arm (1412). When the first counterweight (12) is located at the first placement position, the first rotating arm (1412) abuts against the first limiting structure to limit the downward movement of the first rotating arm (1412).

6. The mass compensation device according to claim 4, characterized in that: The motor of the first steering gear (1411) is a unidirectional capacitor motor or a three-phase induction motor.

7. The mass compensation device according to claim 2, characterized in that: A third protrusion (131) and a fourth protrusion (132) are respectively provided on both end surfaces of the second counterweight (13); The second movable structure (142) comprises a third bracket (1423) and a fourth bracket (1424), and a second connecting block (1425) connected between the third bracket (1423) and the fourth bracket (1424); the third bracket (1423) is configured to be rotatable in a vertical plane; a third mounting hole is provided on the third bracket (1423); a fourth mounting hole is provided on the fourth bracket (1424); the second counterweight (13) is installed between the third bracket (1423) and the fourth bracket (1424); and the third protrusion (131) and the fourth protrusion (132) are respectively provided in the third mounting hole and the fourth mounting hole. In the mounting hole, the diameter of the third mounting hole is greater than the diameter of the third protrusion (131), the diameter of the fourth mounting hole is greater than the diameter of the fourth protrusion (132), the distance between the third bracket (1423) and the fourth bracket (1424) is greater than the distance between the two end surfaces of the second counterweight (13), and when the second movable structure (142) drives the second counterweight (13) to rotate to the second placement position, the bottom wall heights of the third mounting hole and the fourth mounting hole are different, so that when the second counterweight (13) is horizontally placed on the counterweight supporting structure (11), it does not contact the third bracket (1423) and the fourth bracket (1424).

8. The mass compensation device according to claim 7, characterized in that: The second movable structure (142) further comprises a second steering gear (1421) and a second rotating arm (1422); the second rotating arm (1422) is transmission-connected to the second steering gear (1421) and fixedly connected to the third bracket (1423).

9. The mass compensation device according to claim 8, characterized in that: The counterweight switching device (14) further comprises a second limiting structure, which is arranged below the second rotating arm (1422). When the second counterweight (13) is located at the second placement position, the second rotating arm (1422) abuts against the second limiting structure to limit the second rotating arm (1422) from moving downward.

10. The mass compensation device according to claim 8, characterized in that: The motor of the second steering gear (1421) is a unidirectional capacitor motor or a three-phase induction motor.

11. The mass compensation device according to claim 1, characterized in that: The volume of the first counterweight (12) is the same as the volume of the second counterweight (13); and / or The mass compensation device also includes a base (15), the base (15) is arranged above the balance body (2), and the counterweight switching device (14) is installed on the base (15).

12. A magnetic suspension balance assembly, characterized in that: The magnetic suspension balance assembly comprises a magnetic suspension balance and a mass compensation device as claimed in any one of claims 1 to 11, and the magnetic suspension balance comprises a balance body (2).

13. A control method for a magnetic suspension balance assembly, characterized in that: The magnetic suspension balance assembly comprises a magnetic suspension balance and a mass compensation device (1), and the magnetic suspension balance comprises a balance body (2); The mass compensation device (1) comprises: A counterweight supporting structure (11), the counterweight supporting structure (11) being connected to the weighing structure of the balance body (2); a first counterweight (12); a second counterweight (13), wherein the mass of the second counterweight (13) is greater than the mass of the first counterweight (12); a counterweight switching device (14), the counterweight switching device (14) being configured to selectively place one of the first counterweight (12) and the second counterweight (13) on the counterweight supporting structure (11), so as to stabilize the load of the balance body (2) within a set range; The control method comprises: When the weighing is at zero position, controlling the counterweight switching device to place the second counterweight on the counterweight supporting structure; At the weighing working position, the counterweight switching device is controlled to place the first counterweight on the counterweight supporting structure.

14. The control method of the magnetic suspension balance assembly according to claim 13, characterized in that: The counterweight switching device (14) comprises: a first moving structure (141), the first moving structure (141) being configured to drive the first counterweight (12) to move to a first placement position placed on the counterweight supporting structure (11) and a first lifting position not in contact with the counterweight supporting structure (11); the first moving structure (141) comprising a first bracket (1413), a second bracket (1414), a first steering gear (1411), a first rotating arm (1412), and a first connecting block (1415) connected between the first bracket (1413) and the second bracket (1414); the first counterweight (12) being installed between the first bracket (1413) and the second bracket (1414); the first rotating arm (1412) being transmission-connected to the first steering gear (1411), and being fixedly connected to the first bracket (1413); a second mobile structure (142), the second mobile structure (142) being configured to drive the second counterweight (13) to move to a second placement position placed on the counterweight supporting structure (11) and a second lifting position not in contact with the counterweight supporting structure (11); the second mobile structure (142) comprising a third bracket (1423), a fourth bracket (1424), a second steering gear (1421), a second rotating arm (1422), and a second connecting block (1425) connected between the third bracket (1423) and the fourth bracket (1424); the second counterweight (13) is installed between the third bracket (1423) and the fourth bracket (1424); the second rotating arm (1422) is transmission-connected to the second steering gear (1421), and is fixedly connected to the third bracket (1423); The mass compensation device also includes: A first angle detection device, the first angle detection device is used to detect a first angle value of a first angle between the first rotating arm (1412) and a horizontal plane; a second angle detection device, the second angle detection device being used to detect a second angle value of a second angle between the second rotating arm (1422) and the horizontal plane; The first angle is the angle of the first rotating arm (1412) within the moving range between the first placement position and the first lifting position, and the second angle is the angle of the second rotating arm (1422) within the moving range between the second placement position and the second lifting position, and the first angle value and the second angle value are both greater than or equal to 0° and less than 180°; Before the step of "controlling the counterweight switching device to place the first counterweight on the counterweight supporting structure", the control method further includes: Obtaining the first angle value and the second angle value; The step of "controlling the counterweight switching device to place the first counterweight on the counterweight supporting structure" further includes: Based on the first angle value and the second angle value, the first steering gear and / or the second steering gear are controlled to rotate so as to place the first counterweight on the counterweight supporting structure.

15. The control method of the magnetic suspension balance assembly according to claim 14, characterized in that: The step of "controlling the first steering gear and / or the second steering gear to rotate based on the first angle value and the second angle value to place the first counterweight on the counterweight supporting structure" further includes: If the second angle value is greater than or equal to a preset first angle threshold value, and the first angle value is not equal to 0°, the first steering gear is controlled to rotate so that the first angle value is reduced to 0°.

16. The control method of the magnetic suspension balance assembly according to claim 15, characterized in that: The step of "if the second angle value is greater than or equal to a preset first angle threshold value, and the first angle value is not equal to 0°, controlling the first steering gear to rotate so that the first angle value is reduced to 0°" further includes: If the second angle value is greater than or equal to the first angle threshold, and the first angle value is greater than a preset second angle threshold, controlling the first steering gear to rotate at a preset first speed value so that the first angle value is reduced to the second angle threshold; Controlling the first steering gear to rotate at a preset second speed value so that the first angle value is reduced to 0°; wherein the second rate value is less than the first rate value; and / or If the second angle value is greater than or equal to the first angle threshold, and the first angle value is greater than 0° and less than or equal to a preset second angle threshold, the first servo is controlled to rotate at a preset second speed value to reduce the first angle value to 0°.

17. The control method of the magnetic suspension balance assembly according to claim 14, characterized in that: The step of "controlling the first steering gear and / or the second steering gear to rotate based on the first angle value and the second angle value to place the first counterweight on the counterweight supporting structure" further includes: If the second angle value is less than a preset first angle threshold, controlling the second steering gear to rotate so that the second angle value increases to be greater than or equal to the first angle threshold; If the first angle value is not equal to 0°, the first steering gear is controlled to rotate so that the first angle value is reduced to 0°.

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