A threshing cylinder dynamic unbalance targeting self-healing compensation device and control strategy

Abstract

The application provides a threshing cylinder dynamic unbalance targeting self-repairing compensation device and a control strategy, which comprises a data monitoring system and a balancing actuator; one balancing actuator is installed at the left radial disc position of the threshing cylinder, another balancing actuator is installed at the right shaft end position of the threshing cylinder, and the two balancing actuators are coaxial with the threshing cylinder; the balancing actuator is internally provided with a cavity, and the cavity is partially filled with magnetic fluid; the outer side of the balancing actuator is provided with a magnetic field control module; the data monitoring system comprises a vibration sensor, a rotating speed sensor, a photoelectric sensor and an unbalance amount analysis module; the unbalance amount analysis module changes the position of the magnetic fluid in the cavity of the balancing actuator by applying magnetic fields with different phases through the magnetic field control module according to the amplitude and phase measured by the vibration sensor and the phase of the reference signal obtained by the photoelectric sensor. The application can realize real-time detection of the vibration of the cylinder and compensation of the unbalance amount.

Description

Technical Field

[0001] This invention relates to the field of agricultural machinery, and in particular to a targeted self-healing compensation device and control strategy for dynamic imbalance of threshing drum. Background Technology

[0002] The threshing drum, a crucial component of a combine harvester, primarily functions to thresh and separate rice grains. Its threshing and separating performance directly impacts the reliability of the grain combine harvester. Drum vibration induced during the threshing process exists throughout the entire process. Due to the time-varying nature of the feed rate, the drum imbalance is complex and difficult to control. Furthermore, the imbalance not only affects the threshing drum's own performance but can also cause resonance in the frame, vibrating screen, blower, and header, affecting the structural reliability of the combine harvester. Existing offline dynamic balancing methods require machine shutdown for processing and cannot quickly and effectively resolve imbalance problems generated during the threshing drum's operation.

[0003] To address the problems caused by unbalanced vibration of the threshing drum, existing technology discloses a test bench for an in-spindle online dynamic balancing device. This bench utilizes a simulated unbalanced disk with evenly distributed counterweight threaded holes on the outer side of the passive shaft. Screws are installed to alter the mass distribution of the simulated unbalanced disk, thus simulating unbalanced vibration. This meets the experimental research requirements of in-spindle online dynamic balancing devices and is easy to set up. Existing technology also discloses an automatic balancing device and control method for the threshing drum of a combine harvester. An online dynamic balancing detection system collects vibration and speed signals of the threshing drum, calculates the unbalance, and controls the counterweight slider to reach a designated position along a circular guide rail. This enables online active dynamic balancing adjustment of the combine harvester's threshing drum, reducing maintenance time and improving the threshing effect and working efficiency. The prior art discloses an online active balancing head structure and its control method for electromagnetic-permanent magnet hybrid rotating machinery. By designing a simple structure with a wide balancing capacity range, the balancing head can be used online in real time to correct the imbalance of high-speed rotating machinery under rapid speed change conditions, thereby reducing the vibration level of the machine and improving the machine's operating quality, efficiency and life.

[0004] The above-mentioned existing technologies have proposed methods and device designs for active dynamic balancing and dynamic balancing of threshing drums. However, the working state of threshing drums is variable and is affected by external factors such as stalk entanglement, which can cause new imbalance problems. The current automatic balancing devices and control methods cannot be applied to threshing drums. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a targeted self-healing compensation device and control strategy for dynamic imbalance of threshing drums. It can realize real-time detection of drum vibration and compensation of imbalance without machine shutdown, with good real-time performance and high working efficiency.

[0006] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0007] A self-healing compensation device for dynamic imbalance of a threshing drum includes a data monitoring system and a balancing actuator;

[0008] One of the balancing actuators is installed at the left spoke position of the threshing drum, and the other balancing actuator is installed at the right shaft end position of the threshing drum, with both balancing actuators being coaxial with the threshing drum; the balancing actuator has an internal cavity, which is partially filled with magnetic fluid; a magnetic field control module is provided on the outside of the balancing actuator, which changes the position of the magnetic fluid in the cavity of the balancing actuator by applying magnetic fields of different phases;

[0009] The data monitoring system includes a vibration sensor, a speed sensor, a photoelectric sensor, and an unbalance analysis module; the vibration sensor is used to detect the frequency, amplitude, and phase of vibration on the threshing drum bearing housing; the speed sensor is used to detect the speed of the threshing drum; the photoelectric sensor and the vibration sensor are mounted on the same plane with an included angle of φ; the photoelectric sensor is used to acquire the phase of the reference signal.

[0010] The unbalance analysis module, based on the amplitude and phase measured by the vibration sensor and the phase of the reference signal obtained by the photoelectric sensor, applies magnetic fields of different phases through the magnetic field control module to change the position of the magnetofluid in the cavity of the balancing actuator, thereby compensating for the phase of the unbalance.

[0011] Furthermore, the balancing actuator includes a non-magnetic housing, an A-phase electromagnet, a B-phase electromagnet, a ring track, a C-phase electromagnet, a magnetofluid, a D-phase electromagnet, and an outer spoke plate. The non-magnetic housing is made of a magnetically shielding material. The non-magnetic housing is installed on the outside of the outer spoke plate, which is connected to the spokes of the threshing drum. A ring track is provided inside the outer spoke plate, and a magnetofluid is placed inside the ring track. The ring track is made of a material with high magnetic permeability, and the magnetofluid can flow within the ring track under the control of a magnetic field. The A-phase, B-phase, C-phase, and D-phase electromagnets are evenly distributed on the inner side of the outer spoke plate, located in the same plane, to form a magnetic field with a fixed direction to control the flow direction of the magnetofluid. The magnetic field control module controls the flow of the magnetofluid by changing the magnetic field strength of at least one of the A-phase, B-phase, C-phase, and D-phase electromagnets. The outer spoke plate is drivenly connected to the main shaft of the threshing drum.

[0012] A control strategy for a self-healing compensation device for dynamic imbalance of a threshing drum includes the following steps:

[0013] S01: Status monitoring to determine the balance status of the threshing drum;

[0014] S02: When the threshing drum is in an unbalanced state, analyze the unbalanced characteristics and calculate the theoretical unbalance amount;

[0015] S03: Establish a mathematical model and calculate the balance compensation amount;

[0016] S04: Calculate the current required for the balancing device to complete the balancing compensation;

[0017] S05: Balance status feedback, completing the balance of the threshing drum.

[0018] Furthermore, step S01 specifically includes the following steps:

[0019] The data monitoring system can obtain the working amplitude X of the threshing drum under unbalanced conditions through vibration sensors. i and unbalanced phase By X i The balance state of the threshing drum is determined by comparing it with the preset initial amplitude X0. If X... i If X > X0, the threshing drum is in an unbalanced state; if X i If X < X0, then the threshing drum is in a balanced state.

[0020] Furthermore, step S02 specifically includes the following steps:

[0021] When the threshing drum is in an unbalanced state, the data monitoring system obtains the vibration amplitude X1 of the first balancing actuator at one end of the threshing drum and the vibration amplitude X2 of the second balancing actuator at the other end of the threshing drum through the vibration sensor.

[0022] Calculate the theoretical imbalance:

[0023] The vibration amplitudes of the bearings at both ends of the threshing drum are X1 and X2. A current I1 is applied to any electromagnet in the first balancing actuator, causing a change in the mass distribution within the actuator. The amount of this change, U1, is derived based on the correlation between the mass of the magnetohydrodynamic fluid and the magnitude of the current. At this time, the vibration amplitudes X1 and X2 on both sides of the threshing drum are obtained by vibration sensors. 11 'and X 21 ', then the amplitude changes on the correction plane of the first balancing actuator are respectively X 11 '-X1 and X 21 '-X2;

[0024] Let σ be the influence coefficient of the calibration plane of the first balancing actuator on the amplitude measurement at both bearings. 11 and σ 21 ,but:

[0025] A current I2 is applied to any electromagnet in the second balancing actuator, causing a change in the mass distribution within the actuator. The amount of this change, U2, is derived based on the correlation between the mass of the magnetofluid and the magnitude of the current. At this time, vibration amplitudes X on both sides of the threshing drum are obtained via vibration sensors. 12 'and X 22 'Then the amplitude changes on the correction plane of the second balancing actuator are respectively X 12 '-X1 and X 22 '-X2;

[0026] Let σ be the influence coefficient of the correction plane of the second balancing actuator on the amplitude measurement at the bearings on both sides. 12 and σ 22 ,but:

[0027] By establishing equilibrium conditions, the mass change caused by the current flowing through the two equilibrium correction surfaces can be solved:

[0028] The change in mass caused by the application of current to the calibration plane of the first balancing actuator

[0029] The change in mass caused by the current flowing through the correction plane of the second balancing actuator

[0030] Using a two-sided calibration and balancing method, the imbalance of the first balancing actuator is... The imbalance of the second balancing actuator Where r is the geometric radius of the loop.

[0031] Furthermore, step S03 specifically includes the following steps:

[0032] A current I1 is passed through any electromagnet to cause magnetohydrodynamic flow. By comparing experimental and simulation models, the edge curve of the magnetohydrodynamic flow is fitted to obtain a magnetohydrodynamic model state in which the magnetohydrodynamic flow towards the electromagnet forms an ellipse-semicircle. The coordinates of the centroid are determined according to the formula for calculating the centroid of a geometric body. Where a and b are the major and minor axes of the ellipse model, respectively;

[0033] Assuming the total mass of the magnetohydrodynamic fluid filling the loop is M, according to the mass formula for incompressible fluids, we know that:

[0034] The mass of the first balancing actuator is expressed as:

[0035] The mass of the second balancing actuator is expressed as:

[0036] Where ρ is the density of the magnetohydrodynamic fluid, h is the thickness of the ring, R1 is the outer radius of the ring, R2 is the inner radius of the ring; a1 is the major axis of the elliptical model inside the first balancing actuator; b1 is the minor axis of the elliptical model inside the first balancing actuator; a2 is the major axis of the elliptical model inside the second balancing actuator; b2 is the minor axis of the elliptical model inside the second balancing actuator.

[0037] The balance compensation amount can be expressed as the mass-radius product:

[0038] The actual balance compensation amount of the first balancing actuator is:

[0039] The actual balance compensation amount of the second balancing actuator is:

[0040] Furthermore, step S04 specifically includes the following steps:

[0041] By establishing the equation: Solve for the major and minor axes of the magnetohydrodynamic models of the first and second balancing actuators respectively to determine the position of the center of mass;

[0042] Establish the dynamic equations of the magnetohydrodynamic fluid within the first and second balancing actuators:

[0043] The dynamic equations of the magnetohydrodynamic fluid within the first balancing actuator are as follows:

[0044] The dynamic equations of the magnetohydrodynamic fluid within the second balancing actuator are as follows:

[0045] Find the current I1 flowing through the coil of the first balancing actuator and the current I2 flowing through the coil of the second balancing actuator.

[0046] Where ρ is the density of the magnetohydrodynamic fluid, g is the acceleration due to gravity, e is the distance from the end of the electromagnet's core coil to the end of the electromagnet's shaft, ω is the rotational speed of the threshing drum, μ is the permeability of the magnetohydrodynamic fluid, N is the number of coil turns, and S... A Let be the cross-sectional area of ​​the coil, and s be the cross-sectional area of ​​the electromagnet.

[0047] Furthermore, step S05 specifically includes the following steps:

[0048] Step S05 specifically includes the following steps:

[0049] Through unbalanced phase Identify the electromagnets located on both sides of the balance compensation point, or the corresponding electromagnets.

[0050] like Then, by applying a current I1 to the electromagnet on one side of the corresponding balance compensation point in the first balance actuator, a balance compensation amount is formed. By applying a current I2 to the electromagnet on the other side of the corresponding balance compensation point within the second balance actuator, a balance compensation amount is formed. pass and Vector synthesis and balance compensation They are equal in size but opposite in direction, among which

[0051] like Then, by applying a current I1 to the electromagnet on one side of the corresponding balance compensation point in the first balance actuator, a balance compensation amount is formed. By applying a current I2 to the electromagnet on the other side of the corresponding balance compensation point within the second balance actuator, a balance compensation amount is formed. pass and Vector synthesis and balance compensation They are equal in size but opposite in direction, among which

[0052] like Then, by applying a current I1 to the electromagnet corresponding to the balance compensation point in the first balance actuator, a balance compensation amount is formed. Alternatively, a balance compensation amount can be generated by applying a current I2 to the electromagnet corresponding to the balance compensation point within the second balance actuator. or in or

[0053] The amplitude X of the threshing drum is monitored by the vibration sensor of the data monitoring system. I <Initial amplitude X0.

[0054] The beneficial effects of this invention are as follows:

[0055] 1. The dynamic imbalance targeted self-healing compensation device and control strategy of the threshing drum described in this invention provides an automatic balancing device that can be applied to the threshing drum. It transforms the middle and side spokes of the threshing drum into real-time compensation devices, which are installed integrally with the threshing drum to achieve double-sided balance of the imbalance, effectively improving the working efficiency of the threshing drum.

[0056] 2. The targeted self-healing compensation device and control strategy for dynamic imbalance of the threshing drum described in this invention addresses the imbalance problem of the threshing drum of a combine harvester caused by factors such as stalk entanglement or installation errors during operation, as well as the problems of cumbersome operation and low efficiency of traditional dynamic balancing methods. The targeted self-healing compensation strategy described in this invention can realize real-time detection and dynamic balancing of drum vibration without stopping the machine, with good real-time performance and high working efficiency.

[0057] 3. The threshing drum dynamic imbalance targeted self-healing compensation device and control strategy described in this invention addresses the limitations of conventional drum dynamic balancing methods. Based on the flow properties of magnetofluids and electromagnetic drive theory, it uses the magnetic field generated by an electromagnet to control the magnitude and position of the magnetofluid flow rate. The principle is simple and safe.

[0058] 4. The dynamic imbalance target self-healing compensation device and control strategy of the threshing drum described in this invention can calculate the amount of imbalance required for dynamic imbalance compensation by analyzing the vibration signal of the imbalance generated by the detached drum, and adjust the current to control the flow rate of the magnetohydrodynamic fluid to complete the compensation of the imbalance based on the characteristics of the mass distribution change caused by the magnetohydrodynamic effect.

[0059] 5. The threshing drum dynamic imbalance targeted self-healing compensation device and control strategy described in this invention utilizes the eccentric mass generated by the magnetohydrodynamic effect to compensate for the rotor's imbalance. This strategy achieves double-sided balance of rotating machinery by controlling two balancing actuators, and can quickly and effectively achieve targeted self-healing of the imbalance. It is suitable for online dynamic balancing of rotating machinery spindles. Attached Figure Description

[0060] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are some embodiments of the present invention. For those skilled in the art, it is obvious that other drawings can be obtained from these drawings without creative effort.

[0061] Figure 1 This is a schematic diagram of the structure of the threshing drum dynamic imbalance targeted self-healing compensation device described in this invention.

[0062] Figure 2 This is a structural diagram of the first balancing actuator according to a specific embodiment of the present invention.

[0063] Figure 3 This is a phase calibration diagram of a specific embodiment of the present invention.

[0064] Figure 4 This is a schematic diagram of the magnetohydrodynamic mathematical model of a specific embodiment of the present invention.

[0065] Figure 5 This is a schematic diagram illustrating the balance compensation principle of a specific embodiment of the present invention.

[0066] In the picture:

[0067] 1-Data monitoring system; 2-First balancing device; 3-Second balancing device; 4-Threshing drum; 201-Non-magnetic outer shell; 202-A-phase electromagnet; 203-B-phase electromagnet; 204-Spoke hole; 205-Keyway; 206-Ring track; 207-C-phase electromagnet; 208-Magnetic fluid; 209-D-phase electromagnet; 210-Outer spoke disk; 101-Vibration sensor; 102-Speed ​​sensor; 103-Photoelectric sensor; 104-Unbalance analysis module; 105-Magnetic field control module; 106-Power amplifier. Detailed Implementation

[0068] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0069] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "axial," "radial," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0070] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0071] like Figure 1As shown, the threshing drum dynamic imbalance targeted self-healing compensation device of the present invention includes a data monitoring system 1, a first balancing actuator 2, and a second balancing actuator 3. The first balancing actuator 2 is installed at the left spoke position of the threshing drum 4, and the second balancing actuator 3 is installed at the right shaft end position of the threshing drum 4, and the first balancing actuator 2 and the second balancing actuator 3 are coaxial with the threshing drum 4. The first balancing actuator 2 and the second balancing actuator 3 have the same structure. The first balancing actuator 2 has a cavity inside, and the cavity is partially filled with magnetic fluid. A magnetic field control module 105 is provided on the outside of the first balancing actuator 2, which is used to change the position of the magnetic fluid in the cavity of the first balancing actuator 2 by applying magnetic fields of different phases.

[0072] The data monitoring system 1 includes a vibration sensor 101, a speed sensor 102, a photoelectric sensor 103, and an imbalance analysis module 104. The vibration sensor 101 detects the frequency, amplitude, and phase of vibration on the threshing drum bearing seat. The speed sensor 102 detects the rotational speed of the threshing drum 4. The photoelectric sensor 103 and the vibration sensor 101 are mounted on the same plane, with an included angle of [missing information]. The photoelectric sensor 103 is used to acquire the phase of the reference signal;

[0073] The unbalance analysis module 104, based on the frequency, amplitude, and phase measured by the vibration sensor 101 and the phase of the reference signal acquired by the photoelectric sensor 103, controls the magnetic field control module 105 to apply magnetic fields of different phases, thereby changing the position of the magnetofluid within the cavity of the balancing actuator to compensate for the unbalance phase. A power amplifier 106 is provided between the unbalance analysis module 104 and the magnetic field control module 105.

[0074] The first balancing actuator 2 and the second balancing actuator 3 have the same structure. Taking the first balancing actuator 2 as an example, as follows: Figure 2As shown, the balancing actuator 2 includes a non-magnetic housing 201, an A-phase electromagnet 202, a B-phase electromagnet 203, a ring track 206, a C-phase electromagnet 207, a magnetorheological fluid 208, a D-phase electromagnet 209, and an outer spoke disk 210. The non-magnetic housing 201 is made of a magnetically shielding material. The non-magnetic housing 201 is installed on the outside of the outer spoke disk 210. The outer spoke disk 210 is connected to the spokes of the threshing drum 4. The ring track 206 is provided inside the outer spoke disk 210. The magnetorheological fluid 208 is placed inside the ring track 206. The ring track 206 is made of a material with high magnetic permeability. 8 can flow within the ring 206 under magnetic field control; the A-phase electromagnet 202, B-phase electromagnet 203, C-phase electromagnet 207, and D-phase electromagnet 209 are evenly distributed inside the outer radial disk 210 and located in the same plane, used to form a magnetic field with a fixed direction to control the flow direction of the magnetofluid 208; the magnetic field control module 405 controls the flow of the magnetofluid 208 by changing the magnetic field magnitude of at least one of the A-phase electromagnets 202, B-phase electromagnet 203, C-phase electromagnet 207, and D-phase electromagnet 209; the outer radial disk 210 is connected to the main shaft of the threshing drum via a drive.

[0075] like Figure 3 As shown, the frequency, amplitude, and phase measured by the vibration sensor 101 and the reference phase are calibrated by the photoelectric sensor 103. The initial phases of the vibration sensor 101 and the photoelectric sensor 103 are...

[0076] The control strategy of the threshing drum dynamic imbalance targeted self-healing compensation device of the present invention includes the following steps:

[0077] S01: Status monitoring, determining the balance status of the threshing drum 4, specifically including the following steps:

[0078] The data monitoring system 1 can obtain the working amplitude X of the threshing drum 4 under unbalanced conditions through the vibration sensor 101. i and unbalanced phase The amplitude is obtained by performing FFT calculation on the unbalanced vibration signal. This is achieved by using X... i The balance state of the threshing drum 4 is determined by comparing it with the preset initial amplitude X0. If X... i If X > X0, then the threshing drum 4 is in an unbalanced state; if X i If <X0, then the threshing drum 4 is in a balanced state, and i is the number of samplings.

[0079] S02: When the threshing drum 4 is in an unbalanced state, analyze the unbalance characteristics and calculate the theoretical unbalance amount, specifically including the following steps:

[0080] When the threshing drum 4 is in an unbalanced state, the data monitoring system 1 obtains the vibration amplitude X1 of the first balancing actuator 2 at one end of the threshing drum and the vibration amplitude X2 of the second balancing actuator 3 at the other end of the threshing drum through the vibration sensor 101.

[0081] The theoretical imbalance is calculated as follows: the vibration amplitudes of the bearings at both ends of the threshing drum are X1 and X2. A current I1 is applied to any electromagnet on the first balancing actuator 2, causing a change in the mass distribution within the first balancing actuator 2. The amount of change in the mass distribution within the first balancing actuator 2, U1, is derived based on the correlation between the mass of the magnetohydrodynamic fluid and the magnitude of the current. At this time, the vibration amplitudes X1 and X2 on both sides of the threshing drum are obtained by the vibration sensor 101. 11 'and X 21 'Then the amplitude changes on the correction plane of the first balancing actuator 2 are respectively X 11 '-X1 and X 21 '-X2;

[0082] Let σ be the influence coefficient of the correction plane of the first balancing actuator 2 on the amplitude measurement at the bearings on both sides. 11 and σ 21 ,but:

[0083] A current I2 is applied to any electromagnet in the second balancing actuator 3, causing a change in the mass distribution within the actuator 3. The amount of this change, U2, is derived based on the correlation between the mass of the magnetofluid and the magnitude of the current. At this time, the vibration amplitudes X on both sides of the threshing drum are obtained by the vibration sensor 101. 12 'and X 22 'Then the amplitude changes on the correction plane of the second balancing actuator 3 are respectively X 12 '-X1 and X 22 '-X2;

[0084] Let σ be the influence coefficient of the correction plane of the second balancing actuator 3 on the amplitude measurement at the bearings on both sides. 12 and σ 22 ,but:

[0085] By establishing equilibrium conditions, the mass change caused by the current flowing through the two equilibrium correction surfaces can be solved:

[0086] The mass change caused by the current flowing through the correction plane of the first balancing actuator 2

[0087] The mass change caused by the current flowing through the correction plane of the second balancing actuator 3

[0088] Using a double-sided correction balancing method, the imbalance of the first balancing actuator 2 is... The imbalance of the second balancing actuator 3 Where r is the geometric radius of loop 206.

[0089] S03: Establish a mathematical model and calculate the balance compensation amount, specifically including the following steps:

[0090] A current I1 is applied to any electromagnet to cause the magnetofluid 208 to flow. By comparing the experimental and simulation models, the edge curve of the magnetofluid flow is fitted, resulting in a magnetofluid model state where the magnetofluid flows towards the electromagnet in an elliptical-semi-circular manner. The centroid coordinates are determined based on the geometric centroid calculation formula. Where a and b are the major and minor axes of the ellipse model, respectively, as shown below. Figure 4 As shown in the diagram;

[0091] Assuming the total mass of the magnetohydrodynamic fluid filling the annulus 206 is M, according to the mass formula for incompressible fluids, we know that:

[0092] The mass of the first balancing actuator 2 is expressed as:

[0093] The mass of the second balancing actuator 3 is expressed as follows:

[0094] Where ρ is the density of the magnetohydrodynamic fluid, h is the thickness of the annulus 206, R1 is the outer radius of the annulus 206, R2 is the inner radius of the annulus 206; a1 is the major axis of the elliptical model inside the first balancing actuator 2; b1 is the minor axis of the elliptical model inside the first balancing actuator 2; a2 is the major axis of the elliptical model inside the second balancing actuator 3; b2 is the minor axis of the elliptical model inside the second balancing actuator 3.

[0095] The balance compensation amount can be expressed as the mass-radius product:

[0096] The actual balance compensation amount of the first balancing actuator 2 is:

[0097] The actual balance compensation amount of the second balancing actuator 3 is:

[0098] S04: Calculate the current required for the balancing device 2 to complete the balancing compensation, specifically including the following steps:

[0099] By establishing the equation: Solve for the major and minor axes of the magnetohydrodynamic models of the first balancing actuator 2 and the second balancing actuator 3 respectively to determine the position of the center of mass;

[0100] Establish the dynamic equations for the magnetohydrodynamic fluid 208 within the first balancing actuator 2 and the second balancing actuator 3:

[0101] The dynamic equations of the magnetohydrodynamic fluid 208 inside the first balancing actuator 2 are as follows:

[0102] The dynamic equations of the magnetohydrodynamic fluid 208 inside the second balancing actuator 3 are as follows:

[0103] Find the current I1 flowing through the coil of the first balancing actuator 2 and the current I2 flowing through the coil of the second balancing actuator 3.

[0104] Where ρ is the density of the magnetohydrodynamic fluid, g is the acceleration due to gravity, e is the distance from the end of the electromagnet's core coil to the end of the electromagnet's shaft, ω is the rotational speed of the threshing drum, μ is the permeability of the magnetohydrodynamic fluid, N is the number of coil turns, and S... A Let be the cross-sectional area of ​​the coil, and s be the cross-sectional area of ​​the electromagnet.

[0105] S05: Balance status feedback, completing the balance of threshing drum 4, specifically:

[0106] Through unbalanced phase Identify the electromagnets located on both sides of the balance compensation point, or the corresponding electromagnets.

[0107] like Then, by applying a current I1 to the electromagnet on one side of the corresponding balance compensation point in the first balance actuator, a balance compensation amount is formed. By applying a current I2 to the electromagnet on the other side of the corresponding balance compensation point within the second balance actuator, a balance compensation amount is formed. pass and Vector synthesis and balance compensation They are equal in size but opposite in direction, among which

[0108] like Then, by applying a current I1 to the electromagnet on one side of the corresponding balance compensation point in the first balance actuator, a balance compensation amount is formed. By applying a current I2 to the electromagnet on the other side of the corresponding balance compensation point within the second balance actuator, a balance compensation amount is formed. pass and Vector synthesis and balance compensation They are equal in size but opposite in direction, among which

[0109] like Then, by applying a current I1 to the electromagnet corresponding to the balance compensation point in the first balance actuator, a balance compensation amount is formed. Alternatively, a balance compensation amount can be generated by applying a current I2 to the electromagnet corresponding to the balance compensation point within the second balance actuator. or in or

[0110] The vibration sensor of the threshing drum is used to monitor the amplitude X of the threshing drum. i When the amplitude is less than the initial amplitude X0, equilibrium is achieved.

[0111] For example Figure 5 As shown, through unbalanced phase Determined to be in unbalanced phase The electromagnets on both sides are phase A electromagnet 202 and phase D electromagnet 209, and the electromagnets on both sides of the balance compensation point are phase B electromagnet 203 and phase C electromagnet 207.

[0112] As can be seen in the figure Then, by applying a current I1 to the B-phase electromagnet 203 in the first balancing actuator, a balancing compensation amount is formed. By applying a current I2 to the C-phase electromagnet 207 in the second balancing actuator, a balance compensation amount is formed. pass and Vector synthesis and balance compensation They are equal in size but opposite in direction, among which

[0113] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0114] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A control strategy for a threshing cylinder dynamic unbalance targeting self-healing compensation device, characterized in that, The device comprises a data monitoring system (1) and a balance actuator. One of the balance actuators is installed on the left side of the threshing cylinder (4), and the other is installed on the right side of the threshing cylinder (4), and both of them are coaxial with the threshing cylinder (4); the balance actuator is internally provided with a cavity, and the cavity is partially filled with magnetic fluid; the balance actuator is externally provided with a magnetic field control module (105) for changing the position of the magnetic fluid in the cavity by applying magnetic fields of different phases. The data monitoring system (1) comprises a vibration sensor (101), a rotating speed sensor (102), a photoelectric sensor (103) and an unbalance amount analysis module (104); the vibration sensor (101) is used to detect the amplitude and phase of the vibration on the bearing seat of the threshing cylinder; the rotating speed sensor (102) is used to detect the rotating speed of the threshing cylinder (4); the photoelectric sensor (103) is installed on the same plane as the vibration sensor (101) and has an included angle of φ0; the photoelectric sensor (103) is used to obtain the phase of the reference signal; The unbalance amount analysis module (104) changes the position of the magnetic fluid in the cavity of the balance actuator by controlling the magnetic field control module (105) to apply magnetic fields of different phases according to the amplitude and phase measured by the vibration sensor (101) and the phase of the reference signal obtained by the photoelectric sensor (103), so as to compensate for the unbalance amount phase; The balance actuator comprises a non-magnetic shell (201), an A-phase electromagnet (202), a B-phase electromagnet (203), a ring channel (206), a C-phase electromagnet (207), magnetic fluid (208), a D-phase electromagnet (209) and an outer spoke (210); the non-magnetic shell (201) is made of magnetic isolation material; the outer spoke (210) is externally provided with the non-magnetic shell (201), and the outer spoke (210) is connected with the spoke of the threshing cylinder (4); the outer spoke (210) is internally provided with the ring channel (206), and the ring channel (206) is internally provided with the magnetic fluid (208); the ring channel (206) is made of material with high magnetic permeability, and the magnetic fluid (208) can flow in the ring channel (206) under the control of the magnetic field; the A-phase electromagnet (202), the B-phase electromagnet (203), the C-phase electromagnet (207) and the D-phase electromagnet (209) are uniformly distributed on the inner side of the outer spoke (210) and located on the same plane, and are used to form a magnetic field of fixed direction for controlling the flow direction of the magnetic fluid (208); the magnetic field control module (105) controls the flow of the magnetic fluid (208) by changing the magnetic field size of at least one of the A-phase electromagnet (202), the B-phase electromagnet (203), the C-phase electromagnet (207) and the D-phase electromagnet (209); the outer spoke (210) is in driving connection with the main shaft of the threshing cylinder. The control strategy comprises the following steps: S01: state monitoring, judging the balance state of the threshing cylinder (4); S02: When the threshing cylinder (4) is in an unbalanced state, analyze the unbalanced characteristics, calculate the theoretical unbalance amount, specifically including the following steps: When the threshing cylinder (4) is in an unbalanced state, the data monitoring system (1) obtains the vibration amplitude X1 of the first balance actuator (2) at one end of the threshing cylinder and the vibration amplitude X2 of the second balance actuator (3) at the other end of the threshing cylinder through the vibration sensor (101); Calculate the theoretical unbalance amount: The vibration values of the two end bearings of the threshing cylinder are X1 and X2, and the current I1 is input to any electromagnet on the first balance actuator (2), so that the mass distribution in the first balance actuator (2) changes, and the mass distribution change U1 of the first balance actuator (2) is obtained according to the correlation between the magnetic fluid mass and the current; at this time, the vibration values of the two sides of the threshing cylinder are X 11 ’ and X 21 ’ respectively through the vibration sensor (101), and the amplitude change values on the correction plane of the first balance actuator (2) are X 11 ’ - X1 and X 21 ’ - X2 respectively. Let the influence coefficient of the amplitude measurement at the two side bearings respectively by the correction plane of the first balance actuator (2) be σ 11 and σ 21 , then: , ; In the second balance actuator (3) on any electromagnet into the current I2, make the second balance actuator (3) mass distribution changes, the second balance actuator (3) mass distribution changes the amount of U2 according to the correlation between the size of the magnetic fluid mass and the size of the current; At this time, the vibration sensor (101) obtains the vibration amplitude of the threshing cylinder on both sides respectively X 12 ’ and X 22 ’ , then the amplitude change of the second balance actuator (3) on the correction plane is X 12 ’ - X1and X 22 ’ - X2; Let the influence coefficient of the amplitude measurement at the two side bearings by the correction plane of the second balance actuator (3) be σ 12 and σ 22 , then: , ; By establishing the balance condition, the mass change caused by the current flowing through the two balance correction surfaces is solved: The amount of mass change caused by the current flowing through the correction plane of the first balance actuator (2) ; The amount of mass change caused by the current flowing through the correction plane of the second balancing actuator (3) ; The unbalance of the first balancing actuator (2) is balanced by a double-sided correction method ; the unbalance of the second balancing actuator (3) is balanced by a double-sided correction method ; wherein is the geometric radius of the raceway (206); S03: Establish a mathematical model to calculate the balance compensation amount, specifically including the following steps: In any one electromagnet into the current I1 makes the magnetic fluid (208) flow, through the comparison of experiment and simulation model, the edge curve of the magnetic fluid flow is fitted, the magnetic fluid model state of the magnetic fluid flowing to the electromagnet forming an ellipse-semicircle is obtained, the centroid coordinates are determined according to the geometric centroid calculation formula as (0, ), wherein a and b are the long axis and the short axis of the ellipse model respectively; Assume that the total mass of the magnetic fluid liquid filled in the ring (206) is M, according to the mass formula of incompressible liquid: The mass of the first balancing actuator (2) is denoted as: ; The mass of the second balancing actuator (3) is denoted as: ; where p is the density of the magnetic fluid, h is the thickness of the raceway (206), is the outer race radius of the raceway (206), is the inner race radius of the raceway (206); a1 is the major axis of the inner ellipse model of the first balancing actuator (2); b1 is the minor axis of the inner ellipse model of the first balancing actuator (2); a2 is the major axis of the inner ellipse model of the second balancing actuator (3); b2 is the minor axis of the inner ellipse model of the second balancing actuator (3); The balance compensation amount can be expressed by the product of mass and diameter: The actual balance compensation amount of the first balance actuator (2) is ; The actual balance compensation amount of the second balance actuator (3) is ; S04: Calculate the current size required for the balance actuator to complete the balance compensation; S05: Apply balance compensation to complete the balance of the threshing cylinder (4).

2. The control strategy for the self-healing compensation of the dynamic imbalance of a threshing cylinder according to claim 1, characterized in that Step S01 specifically includes the following steps: The data monitoring system (1) can obtain the working amplitude X of the threshing cylinder (4) in the unbalanced state through the vibration sensor (101) i and the unbalanced phase , determine the balanced state of the threshing cylinder (4) by comparing X i with the pre-set initial amplitude X0, if X i >X0, the threshing cylinder (4) is in the unbalanced state; if X i X0, the threshing cylinder (4) is in the balanced state.

3. The control strategy for the self-healing compensation of the dynamic imbalance of a threshing cylinder as claimed in claim 1, characterized in that, Step S04 specifically includes the following steps: By establishing the equation: , The long axis and the short axis of the first balance actuator (2) and the second balance actuator (3) magnetic fluid model are solved respectively to determine the mass center position; Establish the dynamics equation of the magnetic fluid (208) in the first balance actuator (2) and the second balance actuator (3): The kinetic equation of the magnetic fluid (208) in the first balancing actuator (2): ; The kinetic equation of the magnetic fluid (208) in the second balancing actuator (3): ; Solving for the current through the coil of the first balancing actuator (2) and the current through the coil of the second balancing actuator (3) , wherein p is the density of the magnetic fluid, g is the acceleration of gravity, e is the distance from the core coil end of the electromagnet to the shaft end of the electromagnet, ω is the rotational speed of the threshing drum, μ is the magnetic permeability of the magnetic fluid, N is the number of turns of the coil, A is the cross-sectional area of the coil, and s is the cross-sectional area of the electromagnet.

4. The control strategy for the self-healing compensation of the dynamic imbalance of a threshing cylinder as claimed in claim 1, characterized in that, Step S05 specifically includes the following steps: by unbalanced phase , determining electromagnets located on both sides of the balance compensation or corresponding electromagnets; If , the balance compensation amount is formed by applying current to the electromagnet on one side of the corresponding balance compensation position in the first balance actuator (2) ; the balance compensation amount is formed by applying current to the electromagnet on the other side of the corresponding balance compensation position in the second balance actuator (3) ; the vector composition of and is equal in size and opposite in direction to the balance compensation amount , where , ; If , the balance compensation amount is formed by applying current to the electromagnet on one side of the corresponding balance compensation position in the first balance actuator (2) ; the balance compensation amount is formed by applying current to the electromagnet on the other side of the corresponding balance compensation position in the second balance actuator (3) ; the vector sum of and is equal in magnitude and opposite in direction to the balance compensation amount , where , ; If , a balance compensation amount is formed by applying a current to the electromagnet corresponding to the balance compensation position in the first balance actuator (2) , or a balance compensation amount is formed by applying a current to the electromagnet corresponding to the balance compensation position in the second balance actuator (3) , where or ; Monitoring the amplitude of a threshing cylinder by a vibration sensor of a data monitoring system <initial amplitude .

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