A debugging method for a constant-value quasi-zero stiffness vibration isolation structure with double pairs of diagonal rods and negative stiffness

Abstract

The present invention proposes a debugging method for a constant quasi-zero stiffness vibration isolation structure with double pairs of diagonal rod negative stiffness, and the steps are as follows: build a constant quasi-zero stiffness vibration isolation structure including a first pair of diagonal rod assemblies and a second pair of diagonal rod assemblies, and the double pairs of diagonal rod negative stiffness mechanisms are symmetrically arranged on both sides of the positive stiffness mechanism; determine that the pre-compression amount of the horizontal springs in the first pair of diagonal rod assemblies and the second pair of diagonal rod assemblies in the initial state is equal to the horizontal projection length of the diagonal rods; respectively determine the stiffness of the horizontal springs in the first pair of diagonal rod assemblies and the second pair of diagonal rod assemblies and the vertical springs of the positive stiffness mechanism, and construct dimensionless parameters to meet the conditions; when having a constant stiffness characteristic, calculate the stiffness, and calculate the starting vibration isolation frequency according to the relationship between the vibration isolation mass, and if the starting vibration isolation frequency does not meet the design requirements, reconstruct the dimensionless parameters. The present invention can obtain a zero stiffness characteristic that is a straight line near the static equilibrium point, and can obtain a wider range of constant quasi-zero stiffness characteristics.

Description

Technical Field

[0001] The invention relates to the technical field of quasi-zero stiffness vibration isolation, and in particular to a debugging method for a constant-value quasi-zero stiffness vibration isolation structure with negative stiffness of double pairs of oblique rods. Background Art

[0002] Most existing quasi-zero stiffness vibration isolation structures have cubic nonlinear stiffness and only have one static equilibrium position, which is not easy to debug. Reference [1] --- [Thanh Danh Le, Kyoung Kwan Ahn, Avibration isolation system in low frequency excitation region using negative stiffness structure for vehicle seat, Journal of Sound and Vibration, 2011, 330, 6311-6335.] publicly studied a single pair of diagonal rod quasi-zero stiffness model with cubic nonlinear stiffness factors. Under large excitation, the transmissibility bends to the right, reducing the vibration isolation frequency band. In addition, the parameter design method given in this document is complex (including several inequalities), which is not convenient for design and application. Document [2]---The invention patent with application number 202111347500.9 discloses a zero-stiffness vibration isolation structure and method composed of a single pair of diagonal rods with negative stiffness mechanism. Based on the vibration isolator constructed with a single pair of diagonal rods with negative stiffness mechanism, a quasi-zero stiffness debugging method is proposed, but it is obviously different from the present application in terms of structure and debugging method; there is only one set of diagonal rods, and the horizontal spring has large stiffness and size, which leads to the large size of the entire vibration isolation structure. Summary of the invention

[0003] In view of the technical problem that the range of quasi-zero stiffness characteristics of the existing debugging methods of quasi-zero stiffness vibration isolation structures is relatively narrow, the present invention proposes a constant quasi-zero stiffness vibration isolation structure with double pairs of diagonal rods and a debugging method, which can obtain a zero stiffness characteristic of a straight line near the static equilibrium point and a constant quasi-zero stiffness characteristic in a wider range.

[0004] In order to achieve the above object, the technical solution of the present invention is implemented as follows: a debugging method for a constant-value quasi-zero stiffness vibration isolation structure with double pairs of diagonal rod negative stiffness, the steps of which are as follows:

[0005] Step 1: construct a constant-value quasi-zero stiffness vibration isolation structure composed of a double pair of diagonal rod negative stiffness mechanisms including a first pair of diagonal rod assemblies and a second pair of diagonal rod assemblies, wherein the double pair of diagonal rod negative stiffness mechanisms are symmetrically arranged on both sides of the positive stiffness mechanism;

[0006] Step 2: Determine the pre-compression amount of the horizontal springs in the first pair of diagonal rod assemblies and the second pair of diagonal rod assemblies in the initial state Horizontal projection length of the diagonal rod The length of the vertical spring of the positive stiffness mechanism makes the initial state

[0007] Step 3: Determine the stiffness k1 and stiffness k3 of the horizontal springs in the first pair of diagonal rod assemblies and the second pair of diagonal rod assemblies, determine the stiffness k2 of the vertical spring of the positive stiffness mechanism, and construct the dimensionless parameter and Make parameters α and α1 satisfy 0<α<0.25 and 0<α1<0.25;

[0008] Step 4: Draw the force-displacement curve of the constant-value quasi-zero stiffness vibration isolation structure. When it has a constant stiffness characteristic, calculate the stiffness K and calculate the starting vibration isolation frequency based on the relationship between the stiffness K and the vibration isolation mass m. If the initial vibration isolation frequency does not meet the design requirements, repeat steps 2 to 4.

[0009] Preferably, the first pair of diagonal rod assemblies and the second pair of diagonal rod assemblies are vertically arranged.

[0010] Preferably, the first pair of diagonal rod assemblies include diagonal rod group I and diagonal rod group II, and the second pair of diagonal rod assemblies include diagonal rod group III and diagonal rod group IV, diagonal rod group I and diagonal rod group II are symmetrically arranged on both sides of the positive stiffness mechanism, diagonal rod group III and diagonal rod group IV are symmetrically arranged on both sides of the positive stiffness mechanism, and the straight line where the centers of diagonal rod group I and diagonal rod group II are located is perpendicular to the straight line where the centers of diagonal rod group III and diagonal rod group IV are located.

[0011] Preferably, the method for calculating the parameters α and α1 is:

[0012] Draw a force diagram under the initial state and obtain the expression of the applied force f.

[0013]

[0014] Among them, k2 is the vertical spring stiffness, k1 is the stiffness of the horizontal spring of the first pair of diagonal rod assemblies, k3 is the stiffness of the horizontal spring of the second pair of diagonal rod assemblies, δ1 is the pre-compression amount of the horizontal spring of the first pair of diagonal rod assemblies, and δ3 is the pre-compression amount of the horizontal spring of the second pair of diagonal rod assemblies; h is the vertical distance from the initial state to the static equilibrium position, x is the displacement starting from the initial position, y is the displacement starting from the static equilibrium position, and x=y+h; a is the horizontal length between the hinge points at both ends of the diagonal rods of the first pair of diagonal rod assemblies in the initial state; b is the horizontal length between the hinge points at both ends of the diagonal rods of the second pair of diagonal rod assemblies in the initial state;

[0015] For a dimensionless applied force f, divide by Get dimensionless force

[0016]

[0017] For dimensionless forces Find the dimensionless displacement The first-order derivative of , to obtain the dimensionless stiffness:

[0018]

[0019] in, Intermediate variables

[0020] The dimensionless form of the distance h from the initial position to the static equilibrium position is

[0021] At the static equilibrium position, the dimensionless stiffness The quasi-zero stiffness condition of

[0022]

[0023] Through the static equilibrium position The quasi-zero stiffness condition of

[0024]

[0025] Through the above two parameter α1 formulas, parameter α1 is eliminated;

[0026] When the free lengths of the four horizontal springs are the same, and α=α1, When; through the dimensionless stiffness The quasi-zero stiffness condition can be obtained as α = 0.25;

[0027] pass The quasi-zero stiffness condition can be obtained

[0028] Preferably, the initial state or initial position is the position where the intersection of the four inclined rods contacts the top of the vertical spring in the free state, and the static equilibrium position is the position where the four inclined rods are in a horizontal state.

[0029] Preferably, the diagonal rod group I, diagonal rod group II, diagonal rod group III and diagonal rod group IV all include a diagonal rod, a horizontal spring, a transverse guide rod and a horizontal guiding mechanism, one end of the diagonal rod is hinged to the upper part of the positive stiffness mechanism, the other end of the diagonal rod is hinged to the transverse guide rod, the horizontal spring is arranged on the transverse guide rod, and the transverse guide rod is movably connected to the horizontal guiding mechanism.

[0030] Preferably, the horizontal guide mechanism comprises a transverse guide rod linear bearing, one end of the transverse guide rod is slidably arranged in the transverse guide rod linear bearing; the transverse guide rod linear bearing is detachably arranged on a bracket, and the bracket is fixed on the fixed plate.

[0031] Preferably, a radial bearing is fixed to the other end of the transverse guide rod, and the radial bearing is hinged to the other end of the oblique rod through a pin; a retaining spring is fixed to the other end of the transverse guide rod, and a horizontal spring is arranged on the transverse guide rod between the transverse guide rod linear bearing and the retaining spring; a vertical positioning hole is provided on the bracket, and the transverse guide rod linear bearing is detachably connected to the positioning hole through a positioning screw.

[0032] Preferably, the positive stiffness mechanism includes a vertical spring, which is arranged on a vertical spring guide rod, on which a vertical guide rod linear bearing is slidably provided, and the vertical spring is arranged below the vertical guide rod linear bearing; the vertical guide rod linear bearing is respectively hinged to one end of the oblique rods of the first pair of oblique rod assemblies and the second pair of oblique rod assemblies; a load-bearing mechanism is provided on the upper part of the vertical guide rod linear bearing.

[0033] Preferably, the load-bearing mechanism includes a load-bearing plate, which is fixedly connected to the upper part of the vertical guide rod linear bearing of the vertical guide mechanism through a hollow tube; support connecting blocks are fixed on all four sides of the vertical guide rod linear bearing, and the support connecting blocks are fixedly connected to the inclined rod hinge support, and the inclined rod hinge support is hinged to one end of the inclined rod.

[0034] Beneficial effects of the present invention: The present invention belongs to the research scope of quasi-zero stiffness vibration isolation, and is applied to low-frequency vibration isolation engineering problems below a dozen Hz, such as low-frequency excitation and response caused by waves on ships, low-frequency excitation caused by vehicles on the human body, and low-frequency excitation and response caused by spacecraft adjustment. The present invention can be applied to engineering applications of low-frequency vibration isolation to solve the contradictory problem that traditional linear stiffness vibration isolation systems require small dynamic stiffness but produce large static deformation during low-frequency vibration isolation. The present invention realizes a vibration isolator with a constant quasi-zero stiffness characteristic, which solves the problem that traditional quasi-zero stiffness vibration isolators have cubic nonlinearity, and can be used for low-frequency vibration isolation problems with large excitation amplitudes and variable load conditions. Traditional cubic nonlinear stiffness vibration isolators have only one static equilibrium position, while the present application is a constant quasi-zero stiffness vibration isolator with an infinite number of static equilibrium positions.

[0035] Compared with existing literature, the innovation of this patent lies in:

[0036] (1) New structure. Based on the literature [2], a constant quasi-zero stiffness isolator with a double negative stiffness mechanism was proposed. This structure is the first to be proposed in the research of constant quasi-zero stiffness.

[0037] (2) New method. Parameter design was performed for the quasi-zero stiffness vibration isolation model constructed with a double pair of diagonal rods and negative stiffness mechanism proposed in the present invention, and the force and stiffness expressions were obtained (completely different from those in references [1] and [2]); at the static equilibrium point displacement, the stiffness was set equal to zero and the second-order derivative of the stiffness was set equal to zero, and two zero stiffness parameter conditions were obtained. The constant quasi-zero stiffness was adjusted as needed according to the parameter conditions. The constant quasi-zero stiffness adjustment method proposed in the present invention is a brand-new method.

[0038] (3) Outstanding effect. Through the constant quasi-zero stiffness debugging method described in the present invention, a zero stiffness characteristic of a straight line near the static equilibrium point can be obtained, and a constant quasi-zero stiffness characteristic in a wider range can be obtained, which can reduce the resonant frequency of the linear oscillator without any nonlinear factors; compared with the traditional quasi-zero stiffness isolator with weak cubic nonlinear characteristics (Reference 1), under large excitation conditions, the vibration isolation frequency band will not be reduced due to nonlinear bending to the right. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 It is a structural schematic diagram of the present invention.

[0041] Figure 2 for Figure 1 Schematic diagram of the structure of the bracket shown.

[0042] Figure 3 It is a schematic structural diagram of the transverse guide rod of the present invention.

[0043] Figure 4 It is a structural schematic diagram of the oblique rod hinge support of the present invention.

[0044] Figure 5 It is a structural schematic diagram of the support connecting block of the present invention.

[0045] Figure 6 It is a force diagram of the present invention.

[0046] Figure 7 Schematic diagram of the constant quasi-zero stiffness characteristic of the present invention, wherein (a) is the stiffness displacement curve and (b) is the force displacement curve.

[0047] In the figure, 1 is a fixed plate, 2 is a bracket, 3 is a transverse guide rod linear bearing, 4 is a transverse guide rod, 5 is a retaining spring, 6 is a radial bearing, 7 is an inclined rod, 8 is an inclined rod hinge support, 9 is a support connecting block, 10 is a vertical spring guide rod, 11 is a vertical spring, 12 is a hollow tube, 13 is a load plate, 14 is a vertical guide rod linear bearing, and 15 is a horizontal spring. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] A debugging method for a constant-value quasi-zero stiffness vibration isolation structure with double pairs of diagonal rod negative stiffness, the steps of which are as follows:

[0050] Step 1: construct a constant quasi-zero stiffness vibration isolation structure consisting of a double pair of diagonal rod negative stiffness mechanisms including a first pair of diagonal rod assemblies and a second pair of diagonal rod assemblies, wherein the double pair of diagonal rod negative stiffness mechanisms are symmetrically arranged on both sides of the positive stiffness mechanism.

[0051] like Figure 1 As shown, for the convenience of calculation, the first pair of diagonal rod assemblies and the second pair of diagonal rod assemblies are arranged vertically. The placement is more stable, and the number of horizontal springs is large, and the stiffness and size of a single horizontal spring are small, which reduces the cost.

[0052] As a preferred embodiment, the first pair of inclined rod assemblies includes an inclined rod group I and an inclined rod group II, and the second pair of inclined rod assemblies includes an inclined rod group III and an inclined rod group IV, and the inclined rod group I and the inclined rod group II are symmetrically arranged on both sides of the positive stiffness mechanism. Figure 6 As shown, the horizontal length between the hinge points at both ends of the diagonal rod group I and the diagonal rod group II in the initial state is a, the diagonal rod group III and the diagonal rod group IV are symmetrically arranged on both sides of the positive stiffness mechanism, the horizontal length between the hinge points at both ends of the diagonal rod group III and the diagonal rod group IV in the initial state is b, and the straight line where the centers of the diagonal rod group I and the diagonal rod group II are located is perpendicular to the straight line where the centers of the diagonal rod group III and the diagonal rod group IV are located.

[0053] As a preferred embodiment, the inclined rod group I, the inclined rod group II, the inclined rod group III and the inclined rod group IV all include an inclined rod 7, a horizontal spring 15, a transverse guide rod 4 and a horizontal guide mechanism. One end of the inclined rod 7 is hinged to the upper part of the positive stiffness mechanism, that is, the inclined rod 7 can move up and down with the positive stiffness mechanism, and the projection length of the inclined rod 7 on the horizontal spring 15 in the horizontal direction changes with the movement. The other end of the inclined rod 7 is hinged to the transverse guide rod 4, that is, the inclination angle of the inclined rod 7 changes. The horizontal spring 15 is arranged on the transverse guide rod 4, and the transverse guide rod 4 is movably connected to the horizontal guide mechanism. Under the action of the inclined rod 7, the transverse guide rod 4 moves horizontally under the action of the horizontal guide mechanism, thereby compressing the horizontal spring 15.

[0054] The horizontal guide mechanism includes a transverse guide rod linear bearing 3, one end of the transverse guide rod 4 is a bare rod and is slidably arranged in the transverse guide rod linear bearing 3, and the transverse guide rod linear bearing 3 is used to limit the horizontal movement of the transverse guide rod 4. The transverse guide rod linear bearing 3 is detachably arranged on the bracket 2, and the bracket 2 is fixed to the fixed plate 1 by standard bolts. By adjusting the height of the transverse guide rod linear bearing 3 on the bracket 2, the horizontal height of the transverse guide rod 4 can be adjusted. Figure 2 As shown, the bracket 2 is provided with a vertical, long strip positioning hole 201 and a through hole, and the transverse guide rod linear bearing 3 is detachably connected to the positioning hole by a positioning screw. The transverse guide rod linear bearing 3 is arranged in the middle through hole, and the two sides of the transverse guide rod linear bearing 3 are arranged in the positioning hole by positioning screws, so as to realize the positioning of the transverse guide rod linear bearing 3. The transverse guide rod 4 can move horizontally with low friction after being constrained by the transverse guide rod linear bearing 3.

[0055] As a preferred embodiment, Figure 3 As shown, the other end of the transverse guide rod 4 is fixed with a radial bearing 6, and the radial bearing 6 is hinged with the other end of the diagonal rod 7 through a pin; the inner diameter of the radial bearing 6 is the same diameter as the small hole on the transverse guide rod 4, and the outer diameter of the radial bearing 6 forms a transition fit with the circular hole of the diagonal rod 7, thereby realizing the hinge connection between the diagonal rod 7 and the transverse guide rod. A retaining spring 5 is fixed on the other end of the transverse guide rod 4, and a horizontal spring 15 is arranged on the transverse guide rod 4 between the transverse guide rod linear bearing 3 and the retaining spring 5. The transverse guide rod linear bearing 3 and the retaining spring 5 are used to limit the horizontal spring 15. Under the action of a heavy object, the diagonal rod 7 moves downward, thereby pushing the transverse guide rod 4 to move horizontally outward. The transverse guide rod linear bearing 3 has the characteristics of a retaining spring groove (standard part), and the linear bearing 3 is connected to the bracket 2 through a standard retaining spring to constrain the lateral displacement of the transverse guide rod linear bearing 3. The transverse spring 15 is axially constrained by the standard retaining spring 5 and the transverse guide rod linear bearing 3. The elastic force of the transverse spring can be transmitted to the load plate 13 through the inclined rod 7 to obtain the vertical force support force, especially the negative stiffness characteristic in the vertical direction.

[0056] like Figure 4 and Figure 5 As shown, the vertical guide rod linear bearing 14 is fixed with support connection blocks 9 all around, and the support connection blocks 9 are fixedly connected to the inclined rod hinge support 8, and the inclined rod hinge support 8 is hinged to one end of the inclined rod 7. A central through hole is provided in the middle of the support connection block 9, and the central through hole matches the vertical guide rod linear bearing 14, that is, the support connection block 9 is fixed on the vertical guide rod linear bearing 14 and can move up and down with the vertical guide rod linear bearing 14. Fixed holes 91 are provided on both sides of the central through hole, and are fixedly connected to the vertical guide rod linear bearing 14 through the fixed holes 91. Threaded holes 92 are provided on the four sides of the support connection block 9, and the threaded holes 92 are fixedly connected to the inclined rod hinge support 8 through studs, and the other side of the inclined rod hinge support 8 is hinged to the inclined rod 7 through a pin shaft.

[0057] As a preferred embodiment, the positive stiffness mechanism includes a vertical spring 11, which is arranged on a vertical spring guide rod 10, on which a vertical guide rod linear bearing 14 is slidably provided, and the vertical spring 11 is arranged below the vertical guide rod linear bearing 14; the vertical spring guide rod 10 ensures the vertical movement of the vertical spring 11 and the vertical guide rod linear bearing 14 up and down. The lower part of the vertical spring guide rod 10 is fixed on the fixed plate 1. The support connecting block 9 moves up and down with the vertical guide rod linear bearing 14. The vertical guide rod linear bearing 14 is hinged to one end of the diagonal rod 7 of the first pair of diagonal rod assemblies and the second pair of diagonal rod assemblies, respectively, and a load-bearing mechanism is provided on the upper part of the vertical guide rod linear bearing 14. The vertical spring 11 is constrained by the vertical spring guide rod 10, and the vertical displacement is limited by the vertical guide rod linear bearing 14 and the fixed plate 1, so that the load plate 13 obtains load-bearing capacity.

[0058] The load-bearing mechanism includes a load-bearing plate 13, which is fixedly connected to the upper part of the vertical guide rod linear bearing 14 of the vertical guide mechanism through a hollow tube 12. The support connection block 9, the hollow tube 12, the load-bearing plate 13, and the vertical guide rod linear bearing 14 are fastened together by standard long bolts, and the vibration isolation mass force received by the load-bearing plate 13 can be transmitted to the double pairs of diagonal rods 7.

[0059] The diagonal rod 7 and the transverse spring 15 generate vertical negative stiffness, which is called the double-pair diagonal rod negative stiffness mechanism, and is connected in parallel with the positive stiffness of the vertical spring 11. Near the static equilibrium point (the static equilibrium point is where the upper and lower pairs of diagonal rods are in vertically symmetrical positions), according to the debugging method of the present invention, a constant quasi-zero stiffness characteristic can be obtained vertically.

[0060] Step 2: Determine the pre-compression amount of the horizontal springs in the first pair of diagonal rod assemblies and the second pair of diagonal rod assemblies in the initial state Horizontal projection length of the diagonal rod The length of the vertical spring of the positive stiffness mechanism makes the initial state The initial position is a state where the intersection of the first pair of diagonal rod assemblies and the second pair of diagonal rod assemblies contacts the top of the vertical spring in a free state; the static equilibrium position is a state where the diagonal rods are horizontal.

[0061] Step 3: Determine the stiffness k1 and stiffness k3 of the horizontal springs in the first pair of diagonal rod assemblies and the second pair of diagonal rod assemblies, determine the stiffness k2 of the vertical spring of the positive stiffness mechanism, and construct the dimensionless parameter and Make parameters α and α1 satisfy 0<α<0.25 and 0<α1<0.25.

[0062] The method for calculating the parameters α and α1 is:

[0063] Draw the force diagram under the initial state as follows Figure 6 As shown, f h1 is the inward elastic force generated by the lateral spring stiffness k1 and the pre-compression δ1 at the bottom end of the inclined rod with projection a, f h2 is the inward elastic force generated by the lateral spring stiffness k3 and pre-compression δ3 at the bottom end of the inclined rod with projection b, f h The component force in the vertical direction is part of the applied force f. The expression of the applied force f is obtained as:

[0064]

[0065] Among them, k2 is the vertical spring stiffness, k1 is the stiffness of the horizontal spring of the first pair of diagonal rod assemblies, k3 is the stiffness of the horizontal spring of the second pair of diagonal rod assemblies, δ1 is the pre-compression of the horizontal spring of the first pair of diagonal rod assemblies, and the pre-compression length of the transverse spring corresponding to a in the initial state; δ3 is the pre-compression of the horizontal spring of the second pair of diagonal rod assemblies, and the pre-compression length of the transverse spring corresponding to b in the initial state; h is the vertical distance from the initial state to the static equilibrium position, x is the displacement starting from the initial position, y is the displacement starting from the static equilibrium position, and x=y+h; a is the horizontal length between the hinge points at both ends of the diagonal rods of the first pair of diagonal rod assemblies in the initial state; b is the horizontal length between the hinge points at both ends of the diagonal rods of the second pair of diagonal rod assemblies in the initial state; the initial state or initial position is the position where the intersection of the four diagonal rods contacts the top of the vertical spring in the free state, and the static equilibrium position is the position where the four diagonal rods are in a horizontal state. The ratio α of the lateral spring stiffness k1 to the vertical spring stiffness k2 corresponding to a; the ratio α1 of the lateral spring stiffness k3 to the vertical spring stiffness k2 corresponding to b.

[0066] For a dimensionless applied force f, divide by Get dimensionless force

[0067]

[0068] For dimensionless forces Find the dimensionless displacement The first-order derivative of , to obtain the dimensionless stiffness:

[0069]

[0070] in, Intermediate variables

[0071] The dimensionless form of the distance h from the initial position to the static equilibrium position is

[0072] At the static equilibrium position, the dimensionless stiffness The quasi-zero stiffness condition of

[0073]

[0074] Through the static equilibrium position The quasi-zero stiffness condition of

[0075]

[0076] The two parameter condition equations can eliminate an independent parameter. Through the above two parameter α1 formulas, the parameter α1 can be eliminated, reducing one independent parameter.

[0077] When the free lengths of the four horizontal springs are the same, and α=α1, When; through the dimensionless stiffness The quasi-zero stiffness condition can be obtained by α = 0.25. The quasi-zero stiffness condition can be obtained Right now

[0078]

[0079] The ratio α of the stiffness of the selected transverse spring 15 to the stiffness of the vertical spring 11 satisfies 0<α<0.25, and the pre-compression length δ of the transverse spring 15 is equal to the horizontal length a between the two hinge points of the lower pair of diagonal bars of the diagonal bar 7 in the initial state. If the above two conditions are met, the constant quasi-zero stiffness characteristic can be obtained. The static equilibrium position is taken as the zero point displacement, and the static equilibrium point is Figure 6 The quasi-zero stiffness characteristics near the static equilibrium point at the center O point are as follows: Figure 7 As shown, it has the characteristic of constant quasi-zero stiffness. The dynamic stiffness of the vertical spring can be reduced to a constant quasi-zero stiffness state through the negative stiffness mechanism of the double pairs of diagonal rods, while maintaining a relatively high static stiffness to withstand the load. In particular, the constant quasi-zero stiffness can be adjusted as needed.

[0080] The fourth step is to draw the force displacement curve of the constant quasi-zero stiffness vibration isolation structure. When it has a constant stiffness characteristic, calculate the stiffness value K and calculate the starting vibration isolation frequency based on the relationship between the stiffness value K and the vibration isolation mass m. If the initial vibration isolation frequency does not meet the design requirements, repeat steps 2 to 4.

[0081] The initial vibration isolation frequency needs to be less than the designed value. When the constant stiffness characteristic is used, the force under unit deformation is the stiffness. The constant stiffness is a straight line inclined upward on the force-displacement curve, and the slope of the straight line is the stiffness.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A debugging method for a constant-value quasi-zero stiffness vibration isolation structure with double pairs of diagonal rod negative stiffness, characterized in that: The steps are as follows: Step 1: construct a constant-value quasi-zero stiffness vibration isolation structure composed of a double pair of diagonal rod negative stiffness mechanisms including a first pair of diagonal rod assemblies and a second pair of diagonal rod assemblies, wherein the double pair of diagonal rod negative stiffness mechanisms are symmetrically arranged on both sides of the positive stiffness mechanism; Step 2: Determine the pre-compression amount of the horizontal springs in the first pair of diagonal rod assemblies and the second pair of diagonal rod assemblies in the initial state Horizontal projection length of the diagonal rod The length of the vertical spring of the positive stiffness mechanism makes the initial state Step 3: Determine the stiffness k1 and stiffness k3 of the horizontal springs in the first pair of diagonal rod assemblies and the second pair of diagonal rod assemblies, determine the stiffness k2 of the vertical spring of the positive stiffness mechanism, and construct the dimensionless parameter and Make parameters α and α1 satisfy 0<α<0.25 and 0<α1<0.25; Step 4: Draw the force-displacement curve of the constant-value quasi-zero stiffness vibration isolation structure. When it has a constant stiffness characteristic, calculate the stiffness K and calculate the starting vibration isolation frequency based on the relationship between the stiffness K and the vibration isolation mass m. If the initial vibration isolation frequency does not meet the design requirements, repeat steps 2 to 4; The method for calculating parameters α and α1 is: Draw a force diagram under the initial state and obtain the expression of the applied force f. Among them, k2 is the vertical spring stiffness, k1 is the stiffness of the horizontal spring of the first pair of diagonal rod assemblies, k3 is the stiffness of the horizontal spring of the second pair of diagonal rod assemblies, δ1 is the pre-compression amount of the horizontal spring of the first pair of diagonal rod assemblies, and δ3 is the pre-compression amount of the horizontal spring of the second pair of diagonal rod assemblies; h is the vertical distance from the initial state to the static equilibrium position, x is the displacement starting from the initial position, y is the displacement starting from the static equilibrium position, and x=y+h; a is the horizontal length between the hinge points at both ends of the diagonal rods of the first pair of diagonal rod assemblies in the initial state; b is the horizontal length between the hinge points at both ends of the diagonal rods of the second pair of diagonal rod assemblies in the initial state; For a dimensionless applied force f, divide by Get dimensionless force For dimensionless forces Find the dimensionless displacement The first-order derivative of , to obtain the dimensionless stiffness: in, Intermediate variables The dimensionless form of the distance h from the initial position to the static equilibrium position is At the static equilibrium position, the dimensionless stiffness The quasi-zero stiffness condition of Through the static equilibrium position The quasi-zero stiffness condition of Through the above two parameter α1 formulas, parameter α1 is eliminated; When the free lengths of the four horizontal springs are the same, and α=α1, When; through the dimensionless stiffness The quasi-zero stiffness condition can be obtained as α = 0.25; pass The quasi-zero stiffness condition can be obtained 2. The debugging method of the constant-value quasi-zero stiffness vibration isolation structure with double pairs of diagonal rod negative stiffness according to claim 1 is characterized in that: The first pair of diagonal rod assemblies and the second pair of diagonal rod assemblies are vertically arranged.

3. The debugging method of the constant-value quasi-zero stiffness vibration isolation structure with double pairs of diagonal rod negative stiffness according to claim 2 is characterized in that: The first pair of diagonal rod assemblies include diagonal rod group I and diagonal rod group II, and the second pair of diagonal rod assemblies include diagonal rod group III and diagonal rod group IV. Diagonal rod group I and diagonal rod group II are symmetrically arranged on both sides of the positive stiffness mechanism, and diagonal rod group III and diagonal rod group IV are symmetrically arranged on both sides of the positive stiffness mechanism, and the straight line where the centers of diagonal rod group I and diagonal rod group II are located is perpendicular to the straight line where the centers of diagonal rod group III and diagonal rod group IV are located.

4. The debugging method of the constant-value quasi-zero stiffness vibration isolation structure with double pairs of diagonal rods having negative stiffness according to any one of claims 1 to 3, characterized in that: The initial state or initial position is the position where the intersection of the four inclined rods contacts the top of the vertical spring in the free state, and the static equilibrium position is the position where the four inclined rods are in a horizontal state.

5. The debugging method of the constant-value quasi-zero stiffness vibration isolation structure with double pairs of diagonal rod negative stiffness according to claim 3 is characterized in that: The inclined rod group I, the inclined rod group II, the inclined rod group III and the inclined rod group IV all comprise an inclined rod (7), a horizontal spring (15), a transverse guide rod (4) and a horizontal guide mechanism, one end of the inclined rod (7) is hinged to the upper part of the positive stiffness mechanism, the other end of the inclined rod (7) is hinged to the transverse guide rod (4), the horizontal spring (15) is arranged on the transverse guide rod (4), and the transverse guide rod (4) is movably connected to the horizontal guide mechanism.

6. The debugging method of the constant-value quasi-zero stiffness vibration isolation structure with double pairs of diagonal rod negative stiffness according to claim 5 is characterized in that: The horizontal guide mechanism comprises a transverse guide rod linear bearing (3), one end of the transverse guide rod (4) being slidably arranged in the transverse guide rod linear bearing (3); the transverse guide rod linear bearing (3) is detachably arranged on a bracket (2), and the bracket (2) is fixed on a fixed plate (1).

7. The debugging method of the constant-value quasi-zero stiffness vibration isolation structure with double pairs of diagonal rod negative stiffness according to claim 6 is characterized in that: A radial bearing (6) is fixed to the other end of the transverse guide rod (4), and the radial bearing (6) is hinged to the other end of the oblique rod (7) through a pin; a retaining spring (5) is fixed to the other end of the transverse guide rod (4), and a horizontal spring (15) is arranged on the transverse guide rod (4) between the transverse guide rod linear bearing (3) and the retaining spring (5); a vertical positioning hole is provided on the bracket (2), and the transverse guide rod linear bearing (3) is detachably connected to the positioning hole through a positioning screw.

8. The debugging method of the constant-value quasi-zero stiffness vibration isolation structure with double pairs of diagonal rods having negative stiffness according to any one of claims 1, 5, 6 or 7, characterized in that: The positive stiffness mechanism comprises a vertical spring (11), the vertical spring (11) is arranged on a vertical spring guide rod (10), a vertical guide rod linear bearing (14) is slidably arranged on the vertical spring guide rod (10), and the vertical spring (11) is arranged below the vertical guide rod linear bearing (14); the vertical guide rod linear bearing (14) is respectively hinged to one end of the oblique rod (7) of the first pair of oblique rod assemblies and the second pair of oblique rod assemblies; a load-bearing mechanism is arranged on the upper part of the vertical guide rod linear bearing (14).

9. The debugging method of the constant-value quasi-zero stiffness vibration isolation structure with double pairs of diagonal rod negative stiffness according to claim 8 is characterized in that: The load-bearing mechanism comprises a load-bearing plate (13), which is fixedly connected to the upper part of a vertical guide rod linear bearing (14) of a vertical guide mechanism through a hollow tube (12); support connection blocks (9) are fixedly connected around the vertical guide rod linear bearing (14), the support connection blocks (9) are fixedly connected to a diagonal rod hinge support (8), and the diagonal rod hinge support (8) is hinged to one end of the diagonal rod (7).

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