Active vibration reduction platform and control method thereof

Abstract

The invention discloses an active vibration reduction platform and a control method thereof, wherein the active vibration reduction platform comprises: a base, which has a containing cavity inside, and a central through hole is opened on the top plate of the base; wherein the containing cavity is filled with magnetorheological fluid; a support platform, which is arranged above the base; a piston, which is arranged in the base, and the piston comprises: a piston plate and a piston connecting rod; wherein the piston plate is arranged in the containing cavity and is arranged parallel to the top plate; the piston plate can move up and down in the containing cavity; a plurality of through holes are opened on the piston plate; one end of the piston connecting rod is coaxially fixedly connected to the center of the piston plate, and the other end passes through the central through hole and extends to the top of the base and is fixedly connected to the support platform; a permanent magnet is fixedly installed on the inner wall of the base and is located above the piston plate; an electromagnetic coil is wound around the piston connecting rod; an air spring is arranged between the top plate of the base and the support platform, and is sleeved on the piston connecting rod.

Description

Technical Field

[0001] The invention belongs to the technical field of vibration reduction, and in particular relates to an active vibration reduction platform and a control method thereof. Background Art

[0002] With the rapid development of economy, the transportation industry has deeply affected the lives of ordinary people and related to the development and connection of all walks of life. The vibration problem is particularly significant, especially for precision machining and high vibration requirements of technology, good vibration reduction effect is indispensable, so the study of active vibration isolation technology is of great significance.

[0003] Vibration isolation refers to adding appropriate elements to the vibration propagation path to reduce the vibration intensity transmitted to the receiving structure. The damping and natural frequency of the vibration isolation platform are two key factors that have a greater impact on the vibration isolation effect. From the perspective of vibration isolation principle, reducing the stiffness of the vibration isolation platform, increasing the mass of the vibration isolation platform or adding damping are ways to improve the vibration isolation effect, but increasing the mass of the platform is not a good solution. Therefore, the method that can change the platform damping in real time according to the vibration intensity has better applicability.

[0004] Most of the existing shock absorbers have high requirements for mechanical structure and need close coordination. If the mechanical structure design is unreasonable or the coordination is not precise enough, it is difficult to achieve the expected vibration reduction effect. Some shock absorbers also need to be equipped with multiple sensors and complex circuits to estimate the attenuation coefficient, which is easy to make mistakes and cause vibration reduction failure. The current intelligent active shock absorbers generally use the LMS algorithm, which requires the installation of other devices such as displacement sensors to match the step size of the estimation algorithm so that the algorithm can adapt to environmental changes. In addition, because the device is too complicated, the vibration reduction may be poor due to the sensor's incorrect identification of the frequency of the signal to be damped or the existence of electrical signal delays, and the stability and vibration reduction effect of the LMS algorithm are not optimal. Summary of the invention

[0005] One of the purposes of the present invention is to provide an active vibration reduction platform, which can obtain a better active vibration reduction effect by changing the magnetic field strength of the magnetorheological fluid through the cooperation of permanent magnets and electromagnetic coils, and changing the damping force of the magnetorheological fluid on the piston.

[0006] The second object of the present invention is to provide a control method for an active vibration reduction platform, which can control the electrical signal output to the electromagnetic coil according to the vibration signal transmitted to the vibration reduction platform and the temperature of the magnetorheological fluid, thereby achieving control of the vibration reduction damping force and obtaining a better vibration reduction effect.

[0007] The technical solution provided by the present invention is:

[0008] An active vibration reduction platform, comprising:

[0009] A base having a receiving cavity therein, and a central through hole is formed on a top plate of the base;

[0010] Wherein, the containing cavity is filled with magnetorheological fluid;

[0011] A supporting platform, which is arranged above the base;

[0012] A piston is disposed in the base, and the piston comprises: a piston plate and a piston connecting rod;

[0013] Wherein, the piston plate is arranged in the accommodating cavity and is arranged parallel to the top plate; the piston plate can move up and down in the accommodating cavity; a plurality of through holes are opened on the piston plate;

[0014] One end of the piston connecting rod is coaxially fixedly connected to the center of the piston plate, and the other end passes through the central through hole and extends to the top of the base and is fixedly connected to the support platform;

[0015] A permanent magnet, which is fixedly mounted on the inner wall of the base and located above the piston plate;

[0016] an electromagnetic coil wound around the piston connecting rod;

[0017] The air spring is arranged between the top plate of the base and the supporting platform and is sleeved on the piston connecting rod.

[0018] Preferably, a sealing ring is installed in the central through hole.

[0019] Preferably, the side wall of the base extends above the top plate to enclose a groove above the top plate;

[0020] Wherein, the lower end of the air spring is matched and installed in the groove.

[0021] Preferably, the support platform comprises a main body portion and a guide portion;

[0022] The main body is in the shape of a flat plate, the guide portion is arranged along the circumference of the main body and is fixedly connected below the main body; a clearance fit is formed between the inner wall of the guide portion and the outer surface of the side wall of the base.

[0023] Preferably, the side wall of the base is connected to the bottom plate of the base by bolts, and a sealing ring is installed at the connection between the side wall and the bottom plate.

[0024] Preferably, the active vibration reduction platform further comprises:

[0025] A vibration sensor, mounted on the support platform, for detecting the vibration acceleration of the support platform;

[0026] A signal acquisition module, which is electrically connected to the vibration sensor, filters and amplifies the acceleration signal and then outputs it;

[0027] A control module, which is electrically connected to the signal acquisition module and obtains a vibration reduction control signal according to a signal output by the signal acquisition module;

[0028] an output signal processing module, which, together with the control module, is used to amplify the power of the vibration reduction control signal; and

[0029] The electrical control module is electrically connected to the output signal processing module and connected to the electromagnetic coil, and is used to output an electrical signal to the electromagnetic coil.

[0030] A control method for an active vibration reduction platform, using the active vibration reduction platform, comprising:

[0031] Acquire the vibration acceleration of the support, and obtain a basic vibration reduction control signal according to the vibration acceleration signal;

[0032] Acquiring the temperature of the magnetorheological fluid, and obtaining a correction coefficient of the vibration reduction control signal according to the temperature of the magnetorheological fluid; and

[0033] determining a vibration reduction control signal according to the basic vibration reduction control signal and the correction coefficient;

[0034] The calculation method of the vibration reduction control signal is as follows:

[0035]

[0036] Where y′(n) represents the vibration reduction control signal; ξ represents the correction coefficient of the vibration reduction control signal, y(n) represents the basic vibration reduction control signal; t(n) represents the temperature of the magnetorheological fluid, η represents the mechanical friction loss compensation coefficient, and n represents the time n.

[0037] Preferably, the basic vibration reduction control signal y(n) is obtained by a variable step-size convex combination algorithm;

[0038] y(n)=λ(n)y f1 (n)+[1-λ(n)]y f2 (n);

[0039] Where λ(n)=(1+e -α(n) ) -1 ;y f1 (n) is the vibration signal generated by the vibration simulation signal passing through the first-order filter and the vibration signal generated by the estimation of the secondary channel; y f2(n) is the vibration signal generated by the vibration simulation signal passing through the second-order filter and the vibration signal generated by the estimation of the secondary channel; α(n) is the adjustment parameter.

[0040] Preferably, the adjustment parameter α(n) is updated based on the minimum mean square error of the convex combination algorithm:

[0041] α(n+1)=α(n)+μ α e(n)[y f1 (n)-y f2 (n)]λ(n)[1-λ(n)];

[0042] In the formula, μ α is the step size factor of the adjustment parameter, and e(n) represents the residual error signal.

[0043] Preferably, the control method of the active vibration reduction platform further comprises: in the iterative calculation process of the first-order filter and the second-order filter, determining the weight vector update step of the first-order filter and the second-order filter by a multi-objective example algorithm.

[0044] The beneficial effects of the present invention are:

[0045] (1) The active vibration reduction platform provided by the present invention is configured with a magnetorheological fluid in the base, and the magnetic field strength of the magnetorheological fluid is changed by the cooperation of a permanent magnet and an electromagnetic coil, thereby changing the damping force of the magnetorheological fluid on the piston, and by cooperating with an air spring arranged on the lower side of the support platform, the vibration force transmitted to the support platform is offset; the active vibration reduction platform has a simple structure, is easy to assemble, and can achieve a good active vibration reduction effect.

[0046] (2) The control method of the active vibration reduction platform provided by the present invention can realize the control of large loads and medium and low frequency vibrations; the variable step-size convex combination algorithm connects two variable step-size FxLMS algorithms in parallel, and uses genetic algorithm and multi-objective particle algorithm to adjust the step size and order of the convex combination algorithm, which can automatically adjust the parameters according to the input signal, without setting up additional sensors for parameter estimation, thereby realizing active vibration reduction; and it can simultaneously maintain the advantages of fast convergence speed and small steady-state error, as well as good tracking performance; by setting the correction coefficient, it can compensate for the disadvantages of the MR fluid's properties changing due to temperature changes and the vibration reduction signal mismatch problem caused by mechanical losses during the movement of the damping vibration reduction device. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a schematic diagram of the cross-sectional structure of the active vibration reduction platform described in the present invention.

[0048] Figure 2 It is a top view cross-sectional schematic diagram of the active vibration reduction platform described in the present invention.

[0049] Figure 3 It is a schematic structural diagram of the piston plate described in the present invention.

[0050] Figure 4 It is a cross-sectional schematic diagram of the base described in the present invention.

[0051] Figure 5 It is a schematic diagram of a vibration reduction control system of the active vibration reduction platform of the present invention.

[0052] Figure 6 This is the control model diagram of the variable step-length convex combination algorithm described in the present invention.

[0053] Figure 7 This is a vibration reduction flow chart of the variable step-length convex combination algorithm described in the present invention.

[0054] Figure 8 It is a schematic diagram of vibration reduction under random vibration input in the test example of the present invention.

[0055] Fig. 9 It is a vibration transmissibility curve diagram under random vibration input in the test example of the present invention. DETAILED DESCRIPTION

[0056] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0057] like Figure 1-4 As shown, the present invention provides an active vibration reduction platform, including: a base 110, a support platform 120, a piston 130, a permanent magnet 140, an electromagnetic coil 150, a magnetorheological fluid 160 and an air spring 170.

[0058] like Figure 4 As shown, the base 110 is composed of a bottom plate 111, a side wall 112 and a top plate 113, wherein the bottom plate 112 and the top plate 113 are respectively arranged horizontally, and the side wall 112 is arranged vertically. The base 110 has a receiving cavity inside, and the receiving cavity is filled with magnetorheological fluid; the top plate 111 is provided with a central through hole.

[0059] The support platform 120 is arranged above the base 110. The piston 130 is arranged in the receiving cavity of the base 110; the piston 130 includes: a piston plate 131 and a piston connecting rod 132. The piston plate 131 is horizontally arranged in the receiving cavity and can move up and down in the receiving cavity, and the edge of the piston plate 131 is in clearance with the side wall 112 of the base 110; the piston plate 131 divides the receiving cavity into two upper and lower chambers, and a plurality of through holes 131a are provided on the piston plate 131. When the piston plate 131 moves up and down, the magnetorheological fluid 170 in the receiving cavity can flow between the upper and lower chambers through the through holes 131a.

[0060] The lower end of the piston connecting rod 132 is coaxially fixedly connected to the center of the piston plate 131, and the upper end of the piston connecting rod 132 extends through the central through hole on the top plate 111 to the top of the base 110, and is fixedly connected to the support platform 120. In this embodiment, the piston connecting rod 132 is connected to the support platform 120 by bolts to facilitate the installation and replacement of components. Among them, the central through hole on the top plate 111 is a circular through hole, and a sealing ring 111a is installed inside; the piston connecting rod 132 is a cylindrical rod, and the sealing ring 111a contacts the outer surface of the piston connecting rod 132, so that the contact between the piston rod 132 and the central through hole of the top plate 111 is sealed to prevent the magnetorheological fluid 160 from flowing out.

[0061] The permanent magnet 140 is fixedly mounted on the inner wall of the base 110 and is located above the piston plate 130, that is, on the inner wall of the upper chamber of the base 110. The electromagnetic coil 150 is wound around the piston connecting rod 132 and connected to the power supply device through a wire (not shown in the figure).

[0062] As a further preferred embodiment, a groove 132a is provided in the center of the piston connecting rod 132 along the axial direction for installing a wire. A small hole is provided on the piston rod, and the small hole is located in the middle and lower part of the piston rod. The small hole is connected to the groove 132a, and a wire connected to the electrical control module 240 is inserted from the support platform 120, passes through the groove 132a, and passes downward through the small hole to be connected to the electromagnetic coil 150.

[0063] The air spring 170 is disposed between the top plate 111 and the supporting platform 120 , and is sleeved on the piston connecting rod 132 .

[0064] In this embodiment, the side wall 112 of the base 110 extends upward from the top plate 111 to form a groove above the top plate 111 ; wherein the lower end of the air spring 170 is matched and installed in the groove.

[0065] As a further preferred embodiment, the support platform 120 includes a main body 121 and a guide portion 122; the main body 121 is in the shape of a plate, the guide portion 122 is arranged along the circumference of the main body 121, and is fixedly connected to the lower part of the main body 121; a clearance fit is formed between the inner wall of the guide portion 122 and the outer surface of the side wall 112 of the base. The guide portion 122 can place the air spring 170 in a closed space, play a role in protecting the air spring 170, and play a guiding role in the movement of the support platform 120.

[0066] The side wall 112 of the base and the top plate 111 of the base are integrally formed. The side wall 112 and the bottom plate 111 of the base are connected by bolts 111b. A sealing ring 111c is installed at the connection between the side wall 112 and the bottom plate 111 to ensure the sealing effect of the magnetorheological fluid 160.

[0067] like Figure 5 As shown, in this embodiment, the active vibration reduction platform also includes a vibration reduction control system, which includes: a vibration sensor, a temperature sensor, a signal acquisition module 210, a control module 220, an output signal processing module 230 and an electrical control module 240. The vibration sensor is installed on the support platform 120 to detect the vibration acceleration of the support platform 120; the temperature sensor is set in the magnetorheological fluid to monitor the temperature of the magnetorheological fluid; the signal acquisition module 210 is electrically connected to the vibration sensor and the temperature sensor, and outputs the acceleration signal and the temperature signal after filtering and amplifying; the control module 220 is electrically connected to the signal acquisition module 210, and obtains the vibration reduction control signal according to the signal output by the signal acquisition module 210; the output signal processing module 230 is electrically connected to the control module 220, and is used to amplify the power of the vibration reduction control signal; the electrical control module 240 is electrically connected to the output signal processing module 230, and is connected to the electromagnetic coil 150, and is used to output an electrical signal to the electromagnetic coil 150.

[0068] In this embodiment, the control module 220 adopts a DSP controller, including a DSP circuit, a power management circuit, an A / D converter, a D / A converter, a flash memory Flash ROM, a serial communication circuit, etc. The DSP controller is electrically connected to the information acquisition module and the output signal processing module; the flash memory Flash ROM is used to store the control algorithm and hardware configuration information; the serial communication circuit is connected to the DSP circuit and the computer to transmit the signal to the computer for subsequent processing; the A / D converter is connected to the DSP circuit to convert the input analog signal into a digital signal; the D / A converter is connected to the DSP circuit to convert the output digital signal into an analog signal for subsequent control. The variable step length convex combination algorithm is embedded in the control module 220. The control module 220 receives information from the information signal acquisition module 210, performs adaptive adjustment of the convex combination algorithm according to the vibration signal and the error signal, and corrects the signal according to the temperature of the magnetorheological fluid, and then outputs the corresponding vibration reduction control signal, which is transmitted to the output signal processing module 230.

[0069] Compared with the existing vibration reduction platforms, the active vibration reduction platform provided by the present invention has a simple structure and relatively low requirements for assembly precision; the use of a DSP controller in conjunction with algorithm control can ensure real-time control and improve the anti-interference ability of the system.

[0070] like Figure 6-7 As shown, the present invention also provides a control method for an active vibration reduction platform. Using the active vibration reduction platform, the specific control process includes:

[0071] (1) Obtain the vibration acceleration of the support and use the variable step-size convex combination algorithm to obtain the basic vibration reduction control signal. The variable step-size convex combination algorithm achieves better vibration reduction effect by connecting two variable step-size algorithms in parallel. The multi-objective particle algorithm is used to adaptively change the step size of the convex combination algorithm according to the input signal. The algorithm can be changed without the need for additional sensors or other devices. The algorithm can also ensure a small steady-state error.

[0072] like Figure 6 As shown, x(n) is the filtered reference signal collected by the vibration sensor; the expected response d(n) is generated through the primary channel transfer function P(n); H is the secondary channel transfer function, It is an estimate of the secondary channel function. The existence of the secondary channel makes the entire filter more stable; x f (n) is the filtered signal of the reference signal; e(n) is the difference between the expected response d(n) and the output signal y(n), i.e., the residual error signal, x f (n) and e i (n) jointly update the filter weight coefficients, e(n) adjusts the combination coefficient λ(n); the output signal y(n) is the basic vibration reduction control signal.

[0073] The vibration sensor is placed on the support platform 120 to sense the vibration signal. The vibration signal is transmitted to the signal acquisition module, which performs primary filtering on the vibration signal to filter out the sharp signal with a larger amplitude, amplifies the signal, and further transmits it to the control module.

[0074] Firstly, the existing algorithm technology is used to perform offline modeling of primary and secondary paths.

[0075] The basic idea of ​​eliminating vibration signals is that the vibration reduction platform generates a vibration signal with a phase opposite to the primary vibration signal and a similar amplitude, so as to achieve superposition and cancellation of the original vibration signal. When using the convex combination algorithm for vibration reduction, the specific process is as follows:

[0076] The vibration signal x(n) transmitted to the control module is the reference signal of the entire system. The signal first passes through the primary path to generate the desired vibration signal d(n), which is expressed as:

[0077] d(n)=X(n)*P(n)

[0078] The vibration signal passes through the secondary path and is convolved with the secondary channel function h(n) to form a vibration reference signal x f (n), vibration reference signal x f (n) and their respective error signals e i (n) jointly adjust the weight vectors of each filter. The algorithm introduces the secondary path to improve the robustness of the algorithm. In order to ensure that the error signal e(n) can be aligned with the vibration signal x(n) in time, H(n) needs to be compensated. Therefore, the estimation of the secondary channel function is introduced.

[0079] The two weight vectors of the algorithm:

[0080] w i (n+1)=f i [w i (n),x f (n),e i (n)],i=1,2

[0081] Among them, f i is the adaptive function, w i (n) is the weight vector, w1(n) and w2(n) should have the same order, x f (n) represents the input vector.

[0082] The iterative formula of the first-order filtering algorithm is:

[0083] w1(n+1)=w1(n)+μ1|e(n)| p sign(e(n))(X(n)*h(n))

[0084] Where h(n) is the impulse response function of the secondary channel.

[0085] The iterative formula of the second-order filtering algorithm is:

[0086] w2(n+1)=w2(n)+μ2|e(n)| p sign(e(n))(X(n)*h(n))

[0087] The multi-objective particle algorithm is used to select the step size of the convex combination algorithm. The specific steps are as follows:

[0088] Step 1: Randomly initialize the particle population;

[0089] Step 2: Assign the population to the parameters to be determined, and set the step size of the first-order filtering algorithm μ1 = var1, and the step size of the second-order filtering algorithm μ2 = var2;

[0090] Step 3: Substitute the parameters in step 2 into the active vibration control algorithm, calculate the fitness value corresponding to the fitness function, set an objective function to obtain the optimal filter weight coefficient, and derive and calculate the optimal filter weight coefficient with the minimum objective function as the goal. The active vibration control algorithm adopts the minimum mean square error criterion and sets the objective function as J(n) = E[e 2 (n)], e(n) is the error signal;

[0091] Step 4: Determine the individual optimal position and the global optimal position, that is, seek the global optimal step value that meets the optimization goal

[0092] Step 5: First, determine whether the number of iterations of this iteration has reached the upper limit. If it has reached the upper limit, output the optimal value; if it has not reached the upper limit, execute step 6;

[0093] Step 6: Update the population and then execute steps 2 to 5.

[0094] At time n, the vibration signal x(n) passes through the filter to generate the offset vibration signals y1(n) and y2(n), which offset the estimation of the vibration signal entering the secondary channel and generate the output vibration signal y f1 (n), y f2 (n),

[0095]

[0096] In order to coordinate the weights between the two filters, a non-negative combination coefficient λ(n) is introduced, and the total output is

[0097] y(n)=λ(n)y f1 (n)+[1-λ(n)]y f2(n)

[0098] The expression of λ(n) is

[0099] λ(n)=sgm(α(n))=(1+e -α(n) ) -1

[0100] This coefficient is related to the error signal e(n) and is the sigmoid function of the error signal, while the parameter α(n) is an important parameter for adjusting the size of λ(n).

[0101] The parameter α(n) is updated based on the minimum mean square error of the convex combination algorithm.

[0102] α(n+1)=α(n)+μ α e(n)[y f1 (n)-y f2 (n)]λ(n)[1-λ(n)]

[0103] Experiments have shown that when μ α When μ is greater than 3, α The larger the value, the better the performance of the whole algorithm. α When it increases to a certain value, the effect is no longer obvious. α is 200. α(n) and error signal e(n) and output vibration signal y f1 (n), y f2 (n), and the combination parameter λ(n).

[0104] After introducing the combined parameters, the total weight vector is

[0105] w(n)=λ(n)w1(n)+[1-λ(n)]w2(n)

[0106] The error signal e(n) is

[0107] e(n)=d(n)-y(n)

[0108] The goal of this algorithm is to reduce the error signal e(n) to 0, that is, to output a reverse vibration signal y(n) to completely eliminate the original vibration signal x(n).

[0109] (2) Acquiring the temperature of the magnetorheological fluid, and obtaining a correction coefficient of the vibration reduction control signal according to the temperature of the magnetorheological fluid.

[0110] Considering that the properties of magnetorheological fluid are affected by temperature and there is friction during the platform movement, the vibration reduction effect will be affected, so the correction coefficient is set:

[0111] ξ=((3+1.2 -t(n)+50 ) -1+0.78)×η;

[0112] In the formula, ξ represents the correction coefficient of the vibration reduction control signal, t is the temperature of the magnetorheological fluid, the correction coefficient is corrected by an exponential function, η represents the mechanical friction loss compensation coefficient, and η is set to compensate for the mechanical friction loss. According to experience, when η = 1.1, a better correction effect can be achieved, and n represents the nth moment.

[0113] (3) Determine a vibration reduction control signal based on the basic vibration reduction control signal and the correction coefficient.

[0114] Wherein, the calculation method of the vibration reduction control signal is:

[0115] y′(n)=ξ·y(n);

[0116] Where y′(n) represents the vibration reduction control signal; y(n) represents the basic vibration reduction control signal; t(n) represents the temperature of the magnetorheological fluid, η represents the mechanical friction loss compensation coefficient, and n represents the time n.

[0117] The working principle of the active vibration reduction platform is as follows: the support platform 120 is displaced due to vibration, and the rubber air spring 170 is first activated to achieve vibration reduction of high-frequency vibration. After the electromagnetic coil 150 is energized, due to the different voltages, the magnetic field between the electromagnetic coil 150 and the permanent magnet 140 will change accordingly. Under the action of the magnetic field, the viscosity of the magnetorheological fluid 160 will also change accordingly. Under the extrusion of the piston plate 131, the magnetorheological fluid 160 passes through the through hole 131a on the piston plate 131, generating a damping force corresponding to the input signal. The vibration intensity is different, and the signal size output by the control algorithm is different. The viscosity of the magnetorheological fluid changes, and the damping size also changes accordingly when flowing through the perforated plate, achieving active vibration attenuation.

[0118] Test example

[0119] like Figure 7-8 As shown in the figure, the acceleration signal is set to be the superposition of several sinusoidal signals, and the sampling frequency is 8000Hz. Figure 7 It can be seen that the vibration reduction performance of the vibration reduction platform based on the variable step-length convex combination algorithm is good. Under random vibration input, the algorithm can quickly realize vibration attenuation. The vibration amplitude can be decayed to a smaller value within 0.3s, and can be maintained in a small and stable residual vibration signal state, that is, the vibration reduction platform can stably output a specific damping force.

[0120] Under the input of the above acceleration signal, a vibration transmissibility curve is drawn, such as Figure 8 As shown, it can be seen that the vibration attenuation can reach 55 decibels, indicating that the vibration reduction effect of the vibration reduction platform is good.

[0121] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A control method for an active vibration reduction platform, characterized in that: The active vibration reduction platform used includes: A base having a receiving cavity therein, and a central through hole is formed on a top plate of the base; Wherein, the containing cavity is filled with magnetorheological fluid; A supporting platform, which is arranged above the base; A piston is disposed in the base, and the piston comprises: a piston plate and a piston connecting rod; Wherein, the piston plate is arranged in the accommodating cavity and is arranged parallel to the top plate; the piston plate can move up and down in the accommodating cavity; a plurality of through holes are opened on the piston plate; One end of the piston connecting rod is coaxially fixedly connected to the center of the piston plate, and the other end passes through the central through hole and extends to the top of the base and is fixedly connected to the support platform; A permanent magnet, which is fixedly mounted on the inner wall of the base and located above the piston plate; an electromagnetic coil wound around the piston connecting rod; An air spring, which is arranged between the top plate of the base and the support platform and sleeved on the piston connecting rod; The control methods of the active vibration reduction platform include: Acquire the vibration acceleration of the support, and obtain a basic vibration reduction control signal according to the vibration acceleration signal; Acquiring the temperature of the magnetorheological fluid, and obtaining a correction coefficient of the vibration reduction control signal according to the temperature of the magnetorheological fluid; and determining a vibration reduction control signal according to the basic vibration reduction control signal and the correction coefficient; The calculation method of the vibration reduction control signal is as follows: Where y′(n) represents the vibration reduction control signal; ξ represents the correction coefficient of the vibration reduction control signal, y(n) represents the basic vibration reduction control signal; t(n) represents the temperature of the magnetorheological fluid, η represents the mechanical friction loss compensation coefficient, and n represents the time n.

2. The control method of the active vibration reduction platform according to claim 1, characterized in that: A sealing ring is installed in the central through hole.

3. The control method of the active vibration reduction platform according to claim 2, characterized in that: The side wall of the base extends upward from the top plate to enclose a groove above the top plate; Wherein, the lower end of the air spring is matched and installed in the groove.

4. The control method of the active vibration reduction platform according to claim 2 or 3, characterized in that: The support platform includes a main body and a guide portion; The main body is in the shape of a flat plate, the guide portion is arranged along the circumference of the main body and is fixedly connected below the main body; a clearance fit is formed between the inner wall of the guide portion and the outer surface of the side wall of the base.

5. The control method of the active vibration reduction platform according to claim 4, characterized in that: The side wall of the base is connected to the bottom plate of the base through bolts, and a sealing ring is installed at the connection between the side wall and the bottom plate.

6. The control method of the active vibration reduction platform according to claim 5, characterized in that: The active vibration reduction platform also includes: A vibration sensor, mounted on the support platform, for detecting the vibration acceleration of the support platform; A signal acquisition module, which is electrically connected to the vibration sensor, filters and amplifies the acceleration signal and then outputs it; A control module, which is electrically connected to the signal acquisition module and obtains a vibration reduction control signal according to a signal output by the signal acquisition module; an output signal processing module, which, together with the control module, is used to amplify the power of the vibration reduction control signal; and The electrical control module is electrically connected to the output signal processing module and connected to the electromagnetic coil, and is used to output an electrical signal to the electromagnetic coil.

7. The control method of the active vibration reduction platform according to claim 1, characterized in that: The basic vibration reduction control signal y(n) is obtained by a variable step-size convex combination algorithm; y(n)=λ(n)y f1 (n)+[1-λ(n)]y f2 (n): Where λ(n)=(1+e -α(n) ) -1 ;y f1 (n) is the vibration signal generated by the vibration simulation signal passing through the first-order filter and the vibration signal generated by the estimation of the secondary channel; y f2 (n) is the vibration signal generated by the vibration simulation signal passing through the second-order filter and the vibration signal generated by the estimation of the secondary channel; α(n) is the adjustment parameter.

8. The control method of the active vibration reduction platform according to claim 7, characterized in that: The adjustment parameter α(n) is updated based on the minimum mean square error of the convex combination algorithm: α(n+1)=α(n)+μ α e(n)[y f1 (n)-y f2 (n)]λ(n)[1-λ(n)]; In the formula, μ α is the step size factor of the adjustment parameter, and e(n) represents the residual error signal.

9. The control method of the active vibration reduction platform according to claim 8, characterized in that: Also includes: In the iterative calculation process of the first-order filter and the second-order filter, the weight vector update step size of the first-order filter and the second-order filter is determined by a multi-objective example algorithm.

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