Arm flutter suppression damping shock absorber and design method thereof

Abstract

The invention discloses an arm flutter suppression damping shock absorber which comprises a sleeve-shaped shell, an adjusting mechanism is arranged on the upper surface of one end of the shell, tuned mass damping shock absorbers are arranged on the two opposite sides of the adjusting mechanism respectively, and an annular tightening belt is arranged at the other end of the shell. The invention further discloses a design method of the arm flutter suppression damping shock absorber. Typical characteristic information such as the body weight, the tremor frequency, the amplitude and the strength of the patient is collected, a damping block mass and spring stiffness theoretical calculation method is combined, a kinetic model with the upper limbs of the patient as objects is established, and tremor suppression on the arms of the patient is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of flutter suppression device design, and relates to an arm flutter suppression damping vibration isolator. The invention also relates to a design method of the arm flutter suppression damping vibration isolator. Background Art

[0002] Parkinson's disease is a common neurodegenerative disease in the elderly, and it tends to be younger. About 70% of patients have tremor as the first symptom, so it is also called tremor paralysis. The clinical manifestation is tremor at the end of the upper limbs, which seriously affects the patient's diet and daily life. Therefore, it is necessary to develop a tremor suppression device for the end of the patient's upper arm, which is of great significance for the patient to take care of his diet and daily life during the illness and to reduce the burden on the patient's family. At present, the related products developed abroad mainly include anti-shake spoons, vibration-reducing gloves using the principle of gyroscopes, and electronic watches that use reverse vibration to offset upper arm vibration. The use scenario of the anti-shake spoon is relatively limited, and it can only solve the patient's diet problem. The vibration-reducing gloves and electronic watches are expensive and need to be charged from time to time. During charging, the patient still faces the problem of tremor. Summary of the invention

[0003] The object of the present invention is to provide an arm vibration suppression damping vibration absorber, by which arm vibration can be suppressed.

[0004] Another object of the present invention is to provide a design method for an arm vibration suppression damping vibration absorber.

[0005] The first technical solution adopted by the present invention is an arm vibration suppression damping shock absorber, which includes a sleeve-shaped shell, an adjustment mechanism is provided on the upper surface of one end of the shell, tuned mass damping shock absorbers are respectively provided on the opposite sides of the adjustment mechanism, and an annular tightening belt is provided at the other end of the shell.

[0006] The first technical solution of the present invention is also characterized in that:

[0007] The tuned mass damping vibration isolator comprises a square frame-shaped damper support, an inertial mass block is arranged at the center of the damper support, and the periphery of the inertial mass block is connected to the damper support through springs.

[0008] The adjustment mechanism includes a base, a gear is provided at the center of the base, and rack connecting rods are respectively meshed and connected on opposite sides of the gear; a pressure plate is connected to the top of the base through a hexagon socket bolt, and a rubber pad is provided between the pressure plate and the base.

[0009] A groove is provided at one end of the base, a magnetic limit block is arranged in the groove, and there is a continuous magnetic attraction between the magnetic limit block and the metal rack connecting rod.

[0010] Damper covers are respectively arranged on opposite sides of the damper support, and the damper support is connected to the rack connecting rod through a connecting pin.

[0011] The second technical solution adopted by the present invention is a design method of an arm vibration suppression damping shock absorber, which specifically includes the following steps:

[0012] Step 1, connect the three-axis acceleration sensor, the data acquisition instrument, and the host computer in sequence to build a data acquisition system, and fix the acceleration sensor to the upper arm of the object under test;

[0013] Step 2: During measurement, the upper arm of the measured object simulates the patient's tremor, and the acceleration sensor collects the tremor data;

[0014] Step 3, analyzing the patient's flutter frequency and amplitude characteristics based on the data collected in step 2;

[0015] Step 4, use the fft function in Matlab to perform fast Fourier transform on the filtered X, Y, and Z direction data B1, B2, and B3 to generate a spectrum diagram;

[0016] Step 5, establishing a dynamic model of the vibration reduction system;

[0017] Step 6, calculate the parameters in the model established in step 5.

[0018] The second technical solution of the present invention is also characterized in that:

[0019] In step 2, the vibration data collected by the acceleration sensor includes time series Data1_time_AI_1, X-direction vibration data Data1_AI_1, Y-direction vibration data Data1_AI_2, and Z-direction vibration data Data1_AI_3.

[0020] The specific process of step 3 is:

[0021] Step 3.1, read the .mat format file, transpose the column data of Data1_time_AI_1, Data1_AI_1, Data1_AI_2, and Data1_AI_3 into a row matrix, and assign them to variables T, A1, A2, and A3 respectively;

[0022] Step 3.2, use a Butterworth bandpass filter to filter the vibration data in the three directions of A1, A2, and A3, and assign the filtered data row matrix to variables B1, B2, and B3 respectively;

[0023] Step 3.3, generate a time domain graph from the filtered data and display it.

[0024] The specific process of step 5 is: simplify the tuned mass damper into a spring mass block system with a single vibration direction, where the upper arm vibration is the excitation of the spring mass block system, m1 is the mass of the shell and the arm, m2 is the total mass of the inertial mass block, k1 is the stiffness of the connection between the arm and the ground, and k2 is the sum of all spring stiffnesses in a single direction.

[0025] The specific process of step 6 is:

[0026] The equation of motion of the spring-mass system is shown in the following formula (1):

[0027]

[0028] Where Pe iwt is the excitation source, x1 and x2 are the displacements of m1 and m2, The accelerations of m1 and m2 are respectively, and the steady-state solution of the forced vibration under the excitation of the equation is:

[0029]

[0030] Among them, A1 and A2 are the amplitudes of the two steady-state solutions;

[0031] Substituting equation (2) into equation (1) we can obtain the relative amplitude of the main mass:

[0032]

[0033] Where ξ is the damping ratio of the shock absorber, c is the damping between m2 and m1, damping c = 0, therefore, ξ = 0, formula (3) is simplified to:

[0034]

[0035] Let the denominator of equation (4) be equal to zero, and the frequency ratio of the two resonance points is obtained as follows:

[0036]

[0037] When the damping is infinite, the following formula (6) is satisfied:

[0038]

[0039] Let equations (4) and (6) be equal, and the values ​​of λ1 and λ2 corresponding to points G and Q are obtained as follows:

[0040]

[0041] Substituting the values ​​of λ1 and λ2 into equation (5), we can obtain the ordinates of points G and Q respectively:

[0042]

[0043] According to the equal ordinates of points G and Q, we can get the following formula (9):

[0044]

[0045] From formula (7), we can deduce:

[0046]

[0047] From equations (9) and (10), we can obtain:

[0048]

[0049] in, It represents the static displacement of the system under the action of a static force equal to the excitation amplitude P;

[0050] Represents the natural frequency of the main system, which is the vibration system composed of m1 and k1;

[0051] It represents the natural frequency of the shock absorber, which is the vibration system composed of m2 and k2;

[0052] It represents the ratio of the excitation frequency to the natural frequency of the main system;

[0053] It represents the ratio of the natural frequency of the shock absorber to the natural frequency of the main system;

[0054] It represents the ratio of the shock absorber mass to the main system mass.

[0055] The beneficial effect of the present invention is that, according to the patient's weight, tremor frequency and amplitude characteristics, the optimal mass block mass and spring stiffness of the damping shock absorber are calculated to obtain the best tremor suppression effect. The present invention adopts the tuned mass damping vibration reduction principle, and obtains the mass block weight and spring stiffness consistent with the patient's tremor frequency through the calculation method provided by the present invention to achieve resonance, and transfer the patient's arm tremor to the vibration of the mass block, thereby achieving the purpose of tremor suppression. The present invention collects typical characteristic information such as patient weight, tremor frequency, amplitude, intensity, etc., combines the theoretical calculation method of damping block mass and spring stiffness, establishes a dynamic model with the patient's upper limb as the object, and finally suppresses the tremor of the patient's arm according to the tuned mass damping principle. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 It is a schematic structural diagram of the arm vibration suppression damping shock absorber of the present invention;

[0057] Figure 2It is a structural schematic diagram of a tuned mass damping vibration absorber in the arm flutter suppression damping vibration absorber of the present invention;

[0058] Figure 3 It is a schematic diagram of the structure of the connecting rods in the arm flutter suppression damping shock absorber of the present invention moving in opposite directions with equal distance;

[0059] Figure 4 It is a schematic diagram of the limiting principle of the connecting rod in the arm flutter suppression damping shock absorber of the present invention;

[0060] Figure 5 It is a schematic diagram of a connecting fixed rod and a tuned mass damper in the arm flutter suppression damping shock absorber of the present invention;

[0061] Figure 6 It is a schematic diagram of the cooperation between the conical boss and the conical hole in the arm vibration suppression damping shock absorber of the present invention;

[0062] Figure 7 It is a schematic diagram of a housing and a tightening belt in the arm vibration suppression damping shock absorber of the present invention;

[0063] Figure 8 Schematic diagram of data collection for upper arm tremor of patients;

[0064] Fig. 9 It is a physical model of a spring mass block system in a single vibration direction in the arm flutter suppression damping shock absorber design method of the present invention;

[0065] Fig.10 It is a diagram of arm tremor time domain data collected in the arm tremor suppression damping shock absorber design method of the present invention;

[0066] Fig.11 It is a frequency spectrum diagram after smoothing the time domain data in the arm vibration suppression damping vibration isolator design method of the present invention;

[0067] Fig.12 The amplitude-frequency response curve of the physical model of the tuned mass damping shock absorber established in the arm flutter suppression damping shock absorber design method of the present invention;

[0068] Fig.13 is the amplitude curve of the spring-free-inertial mass;

[0069] Fig.14 is the amplitude curve with spring-inertial mass.

[0070] In the figure, 1. damper cover, 2. connecting pin, 3. damper support, 4. rack connecting rod, 5. pressure plate, 6. hexagon socket bolt, 7. rubber pad, 8. base, 9. shell, 10. tightening belt, 11. spring, 12. inertial mass block, 13. gear, 14. magnetic limit block, 15. measured object, 16. acceleration sensor, 17. data acquisition instrument, 18. host computer. DETAILED DESCRIPTION

[0071] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0072] Example 1

[0073] The arm vibration suppression damping shock absorber of the present invention is as follows: Figure 1 As shown, it comprises a sleeve-shaped shell 9, an upper surface of one end of the shell 9 is provided with an adjustment mechanism, two opposite sides of the adjustment mechanism are respectively provided with tuned mass damping shock absorbers, and the other end of the shell 9 is provided with an annular tightening belt 10.

[0074] Example 2

[0075] like Figure 2 As shown, the tuned mass damping shock absorber includes a square frame-shaped damper support 3, an inertial mass block 12 is provided at the center of the damper support 3, the four sides of the inertial mass block 12 are connected to the damper support 3 through springs 11, the upper and lower sides of the inertial mass block 12 are connected to the damper support 3 through two springs 11 respectively, and the left and right sides of the inertial mass block 12 are connected through one spring 11 respectively.

[0076] Damper covers 1 are respectively provided on opposite sides of the damper support 3 , and the damper support 3 is connected to the rack connecting rod 4 through a connecting pin 2 .

[0077] Example 3

[0078] like Figure 3 As shown, the adjustment mechanism includes a base 8, a gear 13 is provided at the center of the base 8, and rack connecting rods 4 are respectively meshed and connected on opposite sides of the gear 13.

[0079] During the push-in adjustment process of the tuned mass damper, when the last tooth of the rack connecting rod 4 is meshed with the gear 13, the two tuned mass dampers reach the narrowest adjustment distance.

[0080] Example 4

[0081] like Figure 4As shown, the magnetic stopper 14 is placed in the groove of the base 8, and the height of the rack connecting rod 4 is 1 mm higher than the base 8. During the external pull adjustment process of the tuned mass damping shock absorber, there is a continuous magnetic attraction between the magnetic stopper 14 and the metal rack connecting rod 4. When the frontmost tooth of the rack connecting rod 4 moves outward to the rotation center of the gear 13, the rack connecting rod 4 absorbs the magnetic stopper 14 into the groove. At this time, the magnetic stopper 14 is stuck in the bottom groove of the rack connecting rod 4 and the groove of the base 8, thereby limiting the rack connecting rod 4.

[0082] Example 5

[0083] like Figure 5 As shown, a pressing plate 5 is connected to the top of the base 8 through a hexagon socket bolt 6, and a rubber pad 7 is provided between the pressing plate 5 and the base 8. When the hexagon socket bolt 6 is tightened, the pressing plate 5 presses the rubber pad 7 downward, and the rubber pad 7 concentrates the pressure on the rack connecting rod 4 to ensure the stability of the rack connecting rod 4.

[0084] like Figure 6 , 7 As shown, in order to increase the connection rigidity between the arm tremor and the vibration of the tuned mass damping shock absorber, a tapered hole is drilled on the shell 9 and a tapered boss is reserved on the base 8. During installation, the tapered boss of the base 8 cooperates with the tapered hole on the shell 9, which makes the vibration transmission efficiency higher and prevents the fixing screws from loosening due to force.

[0085] The method of using the arm vibration suppression damping shock absorber of the present invention is: when wearing it, the arm is inserted into the shell 9, the shell 9 and the arm are fixedly connected by the flexible tightening belt 10, and then the hexagon socket bolt 6 is loosened, and the damper support 3 is manually pushed inward or pulled outward. During the pushing / pulling process, a rack connecting rod 4 is engaged with the gear 13, driving the gear 13 to rotate, and the gear 13 drives the other rack connecting rod 4 to move, so that the two tuned mass damping shock absorbers are moved closer or farther away from each other, thereby adjusting the distance.

[0086] After adjusting the distance, tighten the hexagon socket bolt 6, the pressure plate 5 presses the rubber pad 7 downward, and the rubber pad 7 presses the two rack connecting rods 4 and the gear 13 downward to fix the rack connecting rod 4 and the tuned mass damping shock absorber.

[0087] When the patient's upper arm tremors, the tremor is transmitted to the rack connecting rod 4 through the housing 9, and the rack connecting rod 4 drives the damper support 3 to vibrate. Under the action of inertia and the spring 11, the inertial mass block 12 in the damper support vibrates in the opposite direction to the housing, thereby achieving a vibration reduction effect.

[0088] Example 6

[0089] The design method of the arm tremor suppression damping shock absorber of the present invention calculates the optimal mass block mass and spring stiffness of the tuned mass damping shock absorber according to the patient's weight, tremor frequency and amplitude characteristics to obtain the best tremor suppression effect. The main design methods of the present invention include a method for obtaining typical characteristic information such as the patient's tremor frequency, amplitude, and intensity, a dynamic modeling method based on the tuned mass damping principle with the patient's upper limb as the object, and a theoretical calculation method for the damping block mass and spring stiffness based on the patient's weight parameter.

[0090] The specific steps are as follows:

[0091] Step 1: Build Figure 8 The data acquisition system shown includes a measured object 15, a three-axis acceleration sensor 16 (DYTRAN, 3263M8 type), a data acquisition instrument 17 (DEWETRON), and a host computer 18 installed with data acquisition software (DEWESoftX2 SP1). The acceleration sensor 16 is fixedly connected to the upper arm of the measured object 15.

[0092] Step 2: During the measurement, the upper arm of the measured object 15 simulates the patient's tremor, and the data of the three-axis acceleration sensor 16 can be displayed and stored through the software interface. The target data is exported from the data acquisition software as a .mat file. The data consists of 4 columns, including Data1_time_AI_1 as a time series, Data1_AI_1 as X-axis vibration data, Data1_AI_2 as Y-axis vibration data, and Data1_AI_3 as Z-axis vibration data.

[0093] Step 3: Analyze the patient's flutter frequency and amplitude characteristics in MATLAB software. The specific operation process is as follows:

[0094] Step 3.1, read the .mat format file, transpose the column data of Data1_time_AI_1, Data1_AI_1, Data1_AI_2, and Data1_AI_3 into a row matrix, and assign them to variables T, A1, A2, and A3 respectively.

[0095] Step 3.2, in order to reduce the impact of noise signals on the data, the Butterworth bandpass filter is used to filter the vibration data in the three directions of A1, A2, and A3. Because the human body vibration frequency is 4-6Hz, the passband frequency Wp of the filter is set to 2-8Hz, and the stopband boundary frequency Ws is set to 1Hz and 9Hz respectively; the maximum passband attenuation Rp is 1, and the minimum stopband attenuation Rs is 40. With the above (Wp, Ws, Rp, Rs) parameters as input, the buttord function is used to calculate the minimum order n and cutoff frequency Wn, and then with (n, Wn) as input, the butter function is used to calculate the coefficients b1 and a1 of the Butterworth filter bandpass filter. Finally, with the two coefficients b1 and a1 and the vibration data of a certain direction (A1, A2 or A3) as input, the filter function can be used to realize digital filtering of the data in that direction, and the filtered data row matrix is ​​assigned to variables B1, B2 and B3 respectively.

[0096] Step 3.3, generate a time domain graph from the filtered data and display it. The result is as follows: Fig. 9 As shown, the horizontal axis is time and the vertical axis is amplitude. There are three waveform graphs in rose red, cyan and red, which correspond to the vibration of the tester's arm along the X, Y and Z directions respectively.

[0097] Step 4: Use the fft function in Matlab to perform fast Fourier transform on the filtered X, Y, and Z direction data B1, B2, and B3, and set the sampling frequency fs to 20000 Hz to generate a spectrum. Display the spectrum, and the result is as follows: Fig.10 As shown, from Fig.10 It can be seen that the patient's tremor frequency is 4-6Hz.

[0098] Step 5: Simplify the tuned mass damping shock absorber structure as follows: Fig.11 The single vibration direction shown (i.e. Figure 2 The spring mass block system is composed of four springs 11 in the vertical direction, where the upper arm vibration is the excitation of the spring mass block system, the frequency and amplitude are the results of the analysis in step 3, m1 is the mass of the shell 9 and the arm, m2 is the total mass of the inertial mass block 12, k1 is the stiffness of the connection between the arm and the ground, and k2 is the sum of the stiffness of all springs in a single direction ( Figure 2 Four springs 11 in the vertical direction are provided, and a dynamic model of the vibration reduction system is established based on the physical model.

[0099] Step 6: The mass ratio of m2 to m1 can be calculated based on the magnitude of the exciting force and the target amplitude. m1 is estimated based on the ratio of the upper arm to the body weight, and then the value of the total mass m2 of the inertial mass block is calculated. The spring stiffness k2 is calculated based on the relationship between the natural frequency of the human body and the flutter frequency. The specific process is as follows:

[0100] Step 6.1, Pe iwt It is the excitation source composed of the frequency, amplitude and other parameters of the arm vibration. Fig.11 The equation of motion for the spring-mass system shown can be written as:

[0101]

[0102] In the formula, x1 and x2 are the displacements of m1 and m2, are the accelerations of m1 and m2 respectively. Assume that the steady-state solution of the forced vibration under the excitation of the equation is:

[0103]

[0104] Among them, A1 and A2 are the amplitudes of the two steady-state solutions. In order to facilitate the solution of the equation, the following symbols are introduced:

[0105] ——represents the static displacement of the main system under the static force equal to the excitation amplitude P. The main system is Fig.11 The vibration system composed of m1 and k1;

[0106] ——Indicates the natural frequency of the main system, that is, Fig.11 The vibration system composed of m1 and k1;

[0107] ——Indicates the natural frequency of the shock absorber. Fig.11 The vibration system composed of m2 and k2;

[0108] ——Indicates the ratio of the excitation frequency to the natural frequency of the main system. In the vibration suppression system of Parkinson's patients, the tremor frequency of the patient's upper arm is the excitation frequency;

[0109] ——Indicates the ratio of the natural frequency of the shock absorber to the natural frequency of the main system;

[0110] ——Indicates the ratio of the shock absorber mass block to the main system mass;

[0111] Substituting equation (2) into equation (1), the relative amplitude of the main mass m1 can be obtained:

[0112]

[0113] ξ is the damping ratio of the shock absorber, expressed as: c is the damping between m2 and m1. In the spring mass block system of this design, the damping c = 0, so ξ = 0. The above formula can be simplified to:

[0114]

[0115] When the natural frequency ω2 of the vibration absorber is equal to the frequency ω of the excitation source, the exciting force no longer excites the main system to vibrate, and only the vibration absorber is vibrating; when ω2=ω1, that is, α=1, the vibration reduction system can eliminate the resonance of the main system. For formula (3), (A1 / δ st ) is plotted with the change of λ. It can be seen that when α = 1, the original amplitude of the main system has disappeared, but two new resonance points G and Q appear. When the damping ratio ξ = 0, the amplitude is infinite. Let the denominator of equation (4) equal to zero, and the corresponding frequency ratio of the two new resonance points can be obtained as:

[0116]

[0117] When the damping is infinite, we have:

[0118]

[0119] from Fig.12 It can be seen that no matter what value the damping ratio takes (ξ=0, 0.1, 0.32 or ∞), the response curve will pass through the two points G and Q, that is, the amplitude of the forced vibration of the main system has nothing to do with the size of the damping ratio. Therefore, by making equations (4) and (6) equal, the values ​​of λ1 and λ2 corresponding to the two points G and Q can be obtained as follows:

[0120]

[0121] Substituting the values ​​of λ1 and λ2 into equation (5), we can obtain the ordinates of points G and Q respectively:

[0122]

[0123] If the vertical coordinates of points G and Q are equal and become the highest points on the curve, the designed shock absorber will have the best parameters. According to the equal vertical coordinates of points G and Q, we can get:

[0124]

[0125] From formula (7), we can deduce:

[0126]

[0127] From equations (9) and (10), we can obtain:

[0128]

[0129] The basic process of solving the mass block m2 and spring stiffness k2 of the damping shock absorber of the present invention by the above method is as follows: when the mass of the human body is known, the mass of the single arm is calculated as about 5% of the mass of the human body, and the value of the mass m1 can be obtained; the ratio μ of the mass block of the shock absorber to the mass of the main system is obtained by consulting the data, and the value of the mass block m2 is obtained according to the mass ratio μ; μ is substituted into formula (5) to obtain the value of λ; the upper arm vibration frequency (excitation frequency) ω obtained by experimental data analysis is substituted into the expression of λ to obtain the natural frequency ω1 of the main system; the mass ratio μ is substituted into formula (11) to obtain α, and the natural frequency ω1 of the main system is substituted into the expression of α to obtain the natural frequency ω2 of the shock absorber; the values ​​of ω2 and m2 are substituted into the expression of ω2 to obtain the spring stiffness k2 of the damping shock absorber.

[0130] Example 7

[0131] In order to verify the vibration reduction effect of the structure and dynamic model of the design, the present invention adopts Admas motion simulation software to perform kinematic simulation analysis on the vibration reduction module.

[0132] Step 1: Assume that the target object weighs 40kg. By consulting the data, we know that the mass ratio μ is generally 1%-5%, so μ=0.015. The mass of a single arm accounts for about 5% of the total body weight, and the shell mass is about 0.6kg, so m1 is about 2.6kg. The total mass m2 of the inertial mass block is calculated to be approximately 0.04 kg. According to formula (10), the optimal natural frequency ratio α of the main system and the vibration reduction system is calculated to be 0.985.

[0133] Step 2: The vibration frequency of the upper arm is 4-6Hz, that is, the vibration frequency of the main system is calculated by the formula The calculated natural frequency ω2 of the vibration reduction system is about 3.94-6.91Hz. The spring stiffness k2 of the vibration reduction system in a single direction is calculated to be 0.621-1.91 N / mm. According to step 5, the total mass m2 of the inertial mass block is calculated to be 0.04 kg.

[0134] Step 3, k2 is the sum of all spring stiffnesses in a single direction. The actual stiffness k of a single spring depends on the number of springs N, wire diameter d, number of effective turns n, and material shear modulus G. τ , center diameter D m , series-parallel relationship, the calculation formula for a single spring stiffness is as shown in formula (12).

[0135]

[0136] Step 4: This structure uses 8 springs in a single direction (4 springs in a single direction on one side (see Figure 2There are 4 springs 11) in the vertical direction, and two tuned mass dampers have a total of 8 springs 11) arranged in parallel. The spring wire diameter d is selected to be 0.5 mm and the length is 14 mm, so the effective number of turns n is 28. The spring material is stainless steel, and its material shear modulus G τ 82000MPa, center diameter D m The spring thickness is 5mm, and the stiffness k of a single spring is calculated to be 0.183N / mm, so the k2 value is 1.46N / mm, which is within the range of 0.621-1.91N / mm.

[0137] Step 5, set the parameters of the parts corresponding to 3 in the three-dimensional model in the Admas software. First, according to the calculation results in the previous chapter, the mass of the inertial mass block 12 is set to 0.04kg, the spring stiffness k2 is set to 1.46N / mm, and a sinusoidal excitation force is added to the center of mass of the damper support 3 as a driving source during the simulation. The excitation frequency is 5Hz, the amplitude is 5N, the motion simulation time is 10s, and the output is the displacement of a point on the support 3.

[0138] Step 6: Conduct two sets of comparative experiments. Experiment 1: The spring 11 ( Figure 2 The four springs 11 in the vertical direction are set to an inactive state, and the inertial mass block 12 and the damper support 3 are set to a fixed constraint; Experiment 2: The springs 11 in the three-dimensional model are activated, and the inertial mass block 12 is set to free movement.

[0139] Step 7, obtain the displacement curves of the same point on the damper support 3 under the two experiments for comparative analysis. Fig.13 The curve obtained in Experiment 1 is shown. It can be seen from the figure that the displacement amplitude is about 50 mm. Fig.14 This is the curve obtained from Experiment 2. It can be seen that the frequency of the displacement curve has undergone a large change. This is caused by the combined effect of the inertial mass vibration and the excitation frequency. The vibration amplitude is greatly reduced to about 5mm, basically achieving the effect of vibration reduction.

Claims

1. Arm vibration suppression damping shock absorber, characterized by: It comprises a sleeve-shaped shell (9), an upper surface of one end of the shell (9) is provided with an adjustment mechanism, two opposite sides of the adjustment mechanism are respectively provided with tuned mass damping vibration absorbers, and the other end of the shell (9) is provided with an annular tightening belt (10).

2. The arm vibration suppression damping device according to claim 1, characterized in that: The tuned mass damping vibration absorber comprises a square frame-shaped damper support (3), an inertial mass block (12) is arranged at the center of the damper support (3), and the four sides of the inertial mass block (12) are connected to the damper support (3) via springs (11).

3. The arm vibration suppression damping shock absorber according to claim 2, characterized in that: The adjustment mechanism comprises a base (8), a gear (13) is provided at the center of the base (8), and rack connecting rods (4) are respectively meshed and connected on opposite sides of the gear (13); a pressure plate (5) is connected to the top of the base (8) via a hexagon socket bolt (6), and a rubber pad (7) is provided between the pressure plate (5) and the base (8).

4. The arm vibration suppression damping device according to claim 3, characterized in that: A groove is formed at one end of the base (8), and a magnetic limit block (14) is arranged in the groove. A continuous magnetic attraction exists between the magnetic limit block (14) and the metal rack connecting rod (4).

5. The arm vibration suppression damping shock absorber according to claim 3, characterized in that: The damper support (3) is provided with damper covers (1) on opposite sides thereof, and the damper support (3) is connected to the rack connecting rod (4) via a connecting pin (2).

6. A design method for an arm flutter suppression damping shock absorber, characterized in that: The specific steps include: Step 1, connect the three-axis acceleration sensor (16), the data acquisition instrument (17), and the host computer (18) in sequence to build a data acquisition system, and fix the acceleration sensor (16) to the upper arm of the object to be measured (15); Step 2, during measurement, the upper arm of the measured object (15) simulates the patient's tremor, and the acceleration sensor (16) collects the tremor data; Step 3, analyzing the patient's flutter frequency and amplitude characteristics based on the data collected in step 2; Step 4, use the fft function in Matlab to perform fast Fourier transform on the filtered X, Y, and Z direction data B1, B2, and B3 to generate a spectrum diagram; Step 5, establishing a dynamic model of the vibration reduction system; Step 6, calculate the parameters in the model established in step 5.

7. The design method of the arm vibration suppression damping shock absorber according to claim 6 is characterized in that: In the step 2, the vibration data collected by the acceleration sensor (16) includes a time series Data1_time_AI_1, X-direction vibration data Data1_AI_1, Y-direction vibration data Data1_AI_2, and Z-direction vibration data Data1_AI_3.

8. The design method of the arm vibration suppression damping vibration absorber according to claim 7 is characterized in that: The specific process of step 3 is as follows: Step 3.1, read the .mat format file, transpose the column data of Data1_time_AI_1, Data1_AI_1, Data1_AI_2, and Data1_AI_3 into a row matrix, and assign them to variables T, A1, A2, and A3 respectively; Step 3.2, use a Butterworth bandpass filter to filter the vibration data in the three directions of A1, A2, and A3, and assign the filtered data row matrix to variables B1, B2, and B3 respectively; Step 3.3, generate a time domain graph from the filtered data and display it.

9. The design method of the arm vibration suppression damping vibration absorber according to claim 8, characterized in that: The specific process of step 5 is as follows: simplifying the tuned mass damper into a spring mass block system in a single vibration direction, wherein the upper arm vibration is the excitation of the spring mass block system, m1 is the mass of the shell (9) and the arm, m2 is the total mass of the inertial mass block (12), k1 is the stiffness of the connection part between the arm and the ground, and k2 is the sum of all spring stiffnesses in a single direction.

10. The design method of the arm vibration suppression damping shock absorber according to claim 9, characterized in that: The specific process of step 6 is as follows: The equation of motion of the spring-mass system is shown in the following formula (1): Where Pe iwt is the excitation source, x1 and x2 are the displacements of m1 and m2, The accelerations of m1 and m2 are respectively, and the steady-state solution of the forced vibration under the excitation of the equation is: Among them, A1 and A2 are the amplitudes of the two steady-state solutions; Substituting equation (2) into equation (1) we can obtain the relative amplitude of the main mass: Where ξ is the damping ratio of the shock absorber, c is the damping between m2 and m1, damping c = 0, therefore, ξ = 0, formula (3) is simplified to: Let the denominator of equation (4) be equal to zero, and the frequency ratio of the two resonance points is obtained as follows: When the damping is infinite, the following formula (6) is satisfied: Let equations (4) and (6) be equal, and the values ​​of λ1 and λ2 corresponding to points G and Q are obtained as follows: Substituting the values ​​of λ1 and λ2 into equation (5), we can obtain the ordinates of points G and Q respectively: According to the equal ordinates of points G and Q, we can get the following formula (9): From formula (7), we can deduce: From equations (9) and (10), we can obtain: in, It represents the static displacement of the system under the action of a static force equal to the excitation amplitude P; Represents the natural frequency of the main system, which is the vibration system composed of m1 and k1; It represents the natural frequency of the shock absorber, which is the vibration system composed of m2 and k2; It represents the ratio of the excitation frequency to the natural frequency of the main system; It represents the ratio of the natural frequency of the shock absorber to the natural frequency of the main system; It represents the ratio of the shock absorber mass to the main system mass.

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