CN203717777U - Angular displacement-free vibration isolator and branch chains thereof - Google Patents

Abstract

The utility model relates to an angular displacement-free vibration isolator and branch chains thereof. Each branch chain comprises a first rotary pair and a second rotary pair of which the axes are vertical to each other as well as a third rotary pair and a fourth rotary pair of which the axes are vertical to each other; the first rotary pair is connected with a mobile platform; the fourth rotary pair is connected with a static platform; the axes of the second and third rotary pairs are parallel; the axes of the first and fourth rotary pairs are parallel; each branch chain also comprises a fifth rotary pair and a sixth rotary pair of which the axes are parallel with that of the secondary rotary pair; the second, sixth, third and fifth rotary pairs are connected by a first connection rod, a second connection rod, a third connection rod and a fourth connection rod in sequence; the plane where the axis of the second rotary pair and the axis of the sixth rotary pair are positioned and the plane where the axis of the third rotary pair and the axis of the fifth rotary pair are positioned are parallel. The utility model provides the angular displacement-free vibration isolator and the branch chains used in the angular displacement-free vibration isolator.

Description

A kind of irrotational displacement isolation mounting and side chain thereof

Technical field

The utility model relates to irrotational displacement isolation mounting and the side chain thereof in vibration isolation field.

Background technique

Development along with aeronautical technology, resolution requirement to photo electric imaging system is more and more higher, in many high-resolution aerial photoelectric imaging systems, although used high-quality sensor, but the picture element obtaining is unsatisfactory, the principal element of restriction high-resolution imaging is not often because electricity or optical system cause, this image blurring degeneration is mainly that aviation vibration causes.Photoelectric platform is mounted in surely takes aim at, scouts and search for the device of the purposes such as rescue for optical equipment on aviation aircraft or vehicle, it is carrier that photoelectric platform be take aviation aircraft or vehicle, aviation aircraft or vehicle are conventionally all in vibration environments series of complex, random such as dither, attitude variation, moment of wind resistance and landing impact, the vibration meeting of aircraft or vehicle is passed to optical system by photoelectric platform, affects the image quality of optical system.With respect to line, vibrate, angular vibrations can strengthen the picture amount of moving of image pickup system exponentially, picture element is declined, reduce the resolution of optical system, therefore angular vibrations is on the impact of image quality more than large many of line vibration, and moreover, vibration causes that the rotation of photoelectric platform can cause photoelectric platform system of coordinates to rotate with respect to aircraft system of coordinates, the photoelectric platform that makes to have measurement function is measured inaccurate, brings larger measurement error.So can isolating the above irrotational displacement isolation mounting that can avoid again the relative carrier of photoelectric platform to produce angular vibrations and angular displacement of medium-high frequency (20Hz), development will have great importance.

Model utility content

The purpose of this utility model is to provide a kind of irrotational displacement isolation mounting that angular displacement can be converted into linear displacement; The purpose of this utility model is also to provide the side chain using in a kind of this irrotational displacement isolation mounting.

In order to address the above problem, in the utility model, the technological scheme of side chain is:

The side chain of irrotational displacement transmission device, comprise orthogonal the first revolute pair of axis and the second revolute pair, also comprise orthogonal the 3rd revolute pair of axis and the 4th revolute pair, second, the axis of the 3rd revolute pair is parallel to each other, first, the axis of the 4th revolute pair is parallel to each other, side chain also comprises the 5th revolute pair and the 6th revolute pair that axis parallels with the second revolute pair, the second revolute pair, the 6th revolute pair, between the 3rd revolute pair and the 5th revolute pair, pass through in turn first connecting rod, second connecting rod, third connecting rod is connected with the 4th connecting rod, the axis place plane parallel of the axis place plane of the axis of the second revolute pair and the 6th revolute pair and the axis of the 3rd revolute pair and the 5th revolute pair.

Distance between the axis of the axis of the second revolute pair and the 6th revolute pair is identical with the distance between the axis of the 6th revolute pair and the axis of the 3rd revolute pair.

Between described third connecting rod and the 4th connecting rod, be provided with elastic element.

Described elastic element is identical with the distance between the distance between the axis of described the 5th revolute pair and the tie point between described elastic element and third connecting rod and the axis of described the 5th revolute pair with the tie point between the 4th connecting rod.

Between described first connecting rod and second connecting rod, be provided with damping member.

In the utility model, the technological scheme of Angleless displacement vibration is:

Irrotational displacement transmission device, comprise moving platform and fixed platform, moving, between fixed platform, be provided with at least two side chains that structural type is identical, described side chain comprises orthogonal the first revolute pair of axis, orthogonal the 3rd revolute pair of the second revolute pair and axis, the 4th revolute pair, the first revolute pair is connected with moving platform, the 4th revolute pair is connected with fixed platform, second, the axis of the 3rd revolute pair is parallel to each other, first, the axis of the 4th revolute pair is parallel to each other, each side chain also comprises the 5th revolute pair and the 6th revolute pair that axis parallels with the second revolute pair, the second revolute pair, the 6th revolute pair, between the 3rd revolute pair and the 5th revolute pair, pass through in turn first connecting rod, second connecting rod, third connecting rod is connected with the 4th connecting rod, the axis place plane parallel of the axis place plane of the axis of the second revolute pair and the 6th revolute pair and the axis of the 3rd revolute pair and the 5th revolute pair.

Distance between the axis of the axis of the second revolute pair and the 6th revolute pair is identical with the distance between the axis of the 6th revolute pair and the axis of the 3rd revolute pair.

Between described third connecting rod and the 4th connecting rod, be provided with elastic element.

Described elastic element is identical with the distance between the distance between the axis of described the 5th revolute pair and the tie point between described elastic element and third connecting rod and the axis of described the 5th revolute pair with the tie point between the 4th connecting rod.

It is characterized in that: between described first connecting rod and second connecting rod, be provided with damping member.

The beneficial effects of the utility model are: together with first, second, third, fourth connecting rod and second, the 6th, the 3rd, the 5th revolute pair, form parallelogram linkage, by parallelogram linkage, angular displacement is changed into linear displacement, so the optical equipment that can make to be arranged on moving platform does not produce additional angular displacement, realizes irrotational displacement vibration isolating effect.

Accompanying drawing explanation

Fig. 1 is the structural representation of an embodiment of irrotational displacement isolation mounting in the utility model;

Fig. 2 is the structure principle chart of Fig. 1;

Fig. 3 is the structural representation of side chain in Fig. 1, is also the structural representation of an embodiment of side chain in the utility model simultaneously;

Fig. 4 is moving in Fig. 1, fixed platform and the schematic diagram that coordinates of side chain;

Fig. 5 represents the relation curve between η and ξ, λ.

Embodiment

The embodiment of irrotational displacement isolation mounting is as shown in Fig. 1～4: comprise moving platform 1 and fixed platform 3, moving, fixed platform connects by four side chains 2, four side chains are circumferentially evenly arranged, and the structure of each side chain is all identical, only the structure of one of them side chain are described below.Side chain comprises orthogonal the first revolute pair R6 of axis, orthogonal the 3rd revolute pair R2 of the second revolute pair R5 and axis, the 4th revolute pair R1, second, the axis of the 3rd revolute pair is parallel to each other, first, the axis of the 4th revolute pair is parallel to each other, first, the second revolute pair forms the first Hooke's hinge, the 3rd, the 4th revolute pair forms the second Hooke's hinge, each the 4th revolute pair R1 of four side chains is around the outer rim that is circumferentially connected in fixed platform of fixed platform, the outer rim that is circumferentially connected in moving platform of each first revolute pair R6 moving platform of four side chains, the radius of the first revolute pair R6 place circumference of each side chain is less than the radius of each the 4th revolute pair R1 place circumference.Each side chain also comprises the 5th revolute pair R3 and the 6th revolute pair R4 that axis parallels with the second revolute pair, the second revolute pair, the 6th revolute pair, between the 3rd revolute pair and the 5th revolute pair, pass through in turn first connecting rod 8, second connecting rod 9, third connecting rod 10 is connected with the 4th connecting rod 7, the axis place plane parallel of the axis place plane of the axis of the second revolute pair and the 6th revolute pair and the axis of the 3rd revolute pair and the 5th revolute pair, distance between the axis of the axis of the second revolute pair R5 and the 6th revolute pair R4 is identical with the distance between the axis of the 6th revolute pair R4 and the axis of the 3rd revolute pair R2, first, second, the 3rd, the 4th connecting rod and second, the 6th, the 3rd, the 5th revolute pair forms parallelogram linkage together, first, second, the 3rd, the length of the 4th connecting rod is l.Between described third connecting rod and the 4th connecting rod, be provided with elastic element 5, elastic element is spring, elastic element is connected by ball secondary (or revolute pair) with third connecting rod, the 4th connecting rod, elastic element is identical with the distance between the distance between the axis of the 5th revolute pair and the tie point between described elastic element and third connecting rod and the axis of described the 5th revolute pair with the tie point between the 4th connecting rod, and is ρ _k.Between described first connecting rod and second connecting rod, be provided with damping member 4, damping member with first, second connecting rod by secondary 6(of ball or revolute pair) be connected, damping member is identical with the distance between the distance between the axis of the 6th revolute pair R4 and the tie point between damping member and second connecting rod and the axis of the 6th revolute pair with the tie point between first connecting rod, and is ρ _c.

As shown in Figure 4: when side chain is in nonsingular position shape (nonsingular position shape is that straight the 5th, the 6th revolute pair does not overlap, and second, third revolute pair does not overlap), side chain will produce two constraint couples to moving platform because these two couples are all perpendicular to R1, R2 and R5, R6, so these two couples are parallel to each other.About the analysis of the freedom of movement of this irrotational displacement isolation mounting as shown in Figure 4: order is moving, fixed platform two platforms are parallel, by the connecting mode shown in Fig. 1, the Hooke pair of side chain one end is distributed on the circumference that moving platform plane inside radius is rm, it is rb(rb>rm that the Hooke pair of the other end is distributed in fixed platform plane inside radius) circumference on, so just be built into paralleling mechanism, the schematic diagram that Fig. 4 is paralleling mechanism.

Disjunctor system of coordinates Ob-XbYbZb is set on the fixed platform of paralleling mechanism, its Xb, Yb axle are in fixed platform plane, Xb axle points to the central point B1 of Hooke pair on fixed platform, true origin is positioned at fixed platform center, B2, B3, B4 represent respectively the central point of other Hooke pair on fixed platform, and M1, M2, M3 and M4 represent the central point of corresponding Hooke pair on moving platform.Suppose that all side chains of isolation mounting are all under the shape of nonsingular position, all side chains represent the number of side chain to the raw 2n(n of moving platform common property) individual constraint couple, moving when initial, fixed platform is parallel, and rb>rm, therefore in the situation that moving, fixed platform plane do not overlap, this 2n constraint couple neither can be parallel to same plane, also can not be parallel to same straight line, so this 2n constraint couple certainly exists 3 independently bases with can be expressed as

? one group of base of backpitch can be written as

Known according to screw theory for the possible kinematic screw of moving platform, therefore n-TRRT(n represents the number of side chain, each letter in TRRT represents respectively Hooke's hinge, revolute pair, revolute pair and Hooke's hinge) may the moving as the D translation along Xb, Yb, Zb coordinate axes moves of the relative fixed platform of moving platform of paralleling mechanism, and move without corner.

The layout of elasticity, damping member.

As shown in Figure 3, pass through respectively secondary (or revolute pair) elastic elements of ball and damping member between two pairs of connecting rods in each side chain and that R3, R4 are connected, two balls distance secondary and R3 of elastic elements is all ρ _k, two balls distance secondary and R4 that damping member is installed is all ρ _c, order

σ _k＝ρ _k/l，σ _c＝ρ _c/l

Each branch all can produce 1 elastic force arrow to moving platform vow with 1 damping force these two power are vowed two the T Fu centers in branch of all passing through.For n-TRRT paralleling mechanism, due to rb>rm, therefore in the situation that moving, fixed platform plane do not overlap, its branch vows and neither can be parallel to same plane the 2n of moving platform elastic damping power, can not be parallel to same straight line yet, so this 2n elastic damping power is vowed and is certainly existed 3 independently bases, can be expressed as

Wherein, l ₂, l ₃, m ₁, m ₃, n ₁, n ₂be real number.

As can be seen here, minute giving moving platform and provide along the three dimensional elasticity damping force of Xb, Yb, Zb coordinate axes after elastic damping element has been installed, this lays a good foundation for realizing three-dimensional isolation, and the layout that shows elastic damping element is rational.

By elastic damping element, drive space to the velocity Jacobian Matrix Solving of moving platform cartesian space.

As shown in Figure 2, on the moving platform of n-TRRT vibration isolator in parallel, disjunctor system of coordinates Om-XmYmZm is set, its Xm, Ym axle are in moving platform plane, and true origin is positioned at moving platform center, and the sensing of Xm, Ym axle and Xb, Yb axle are identical.

Inertial coodinate system O-XYZ is set, and the sensing of its X, Y, Z axis and Xb, Yb, Zb axle are identical, and origin position is any.If the elastic element of installing in n-TRRT paralleling mechanism branch is in mechanism, the rigidity when working equilibrium position is all k, the damping constant of damping member is all c, the gross mass of moving platform and load is m, according to function calculating principle, can try to achieve respectively vibration isolator at inertial matrix, stiffness matrix and the damping matrix of work equilibrium position like this

$M=\left[\begin{array}{ccc}m& 0& 0\\ 0& m& 0\\ 0& 0& m\end{array}\right],K={\mathrm{kJ}}_k^T{J}_k=\left[\begin{array}{ccc}\frac{n}{3}{\mathrm{\σ}}_k^{2}k& 0& 0\\ 0& \frac{n}{3}{\mathrm{\σ}}_k^{2}k& 0\\ 0& 0& \frac{n}{3}{\mathrm{\σ}}_k^{2}k\end{array}\right],C={\mathrm{cJ}}_c^T{J}_c=\left[\begin{array}{ccc}\frac{n}{3}{\mathrm{\σ}}_c^{2}c& 0& 0\\ 0& \frac{n}{3}{\mathrm{\σ}}_c^{2}c& 0\\ 0& 0& \frac{n}{3}{\mathrm{\σ}}_c^{2}c\end{array}\right]$

By these three matrixes, can be found out, when moving platform center in fixed platform system of coordinates in work equilibrium position time, the inertia of vibration isolator, rigidity and damping be not only decoupling zero on three-dimensional, and identical.

The parameter designing of elastic damping element

Because n-TRRT vibration isolator in parallel has the feature of the three-dimensional same sex and decoupling in work equilibrium position, therefore this type systematic first can be reduced to the single degree of freedom system along either direction, then carry out analysis and the design of system.

If moving platform along the vibration displacement of inertial coodinate system Z-direction and speed be respectively z, fixed platform is respectively z along vibration displacement and the speed of inertial coodinate system Z-direction ₀, theoretical according to little displacement vibration, be easy to try to achieve vibration isolator along the little displacement vibration equation of Z-direction

$m\stackrel{..}{z}+\frac{n}{3}{\mathrm{\σ}}_c^{2}c\stackrel{.}{z}+\frac{n}{3}{\mathrm{\σ}}_k^2\mathrm{kz}=\frac{n}{3}{\mathrm{\σ}}_c^{2}c{\stackrel{.}{z}}_0+\frac{n}{3}{\mathrm{\σ}}_k^{2}k{z}_0$

If fixed platform working frequency is f(Hz) simple harmonic oscillation, system along the vibration displacement transfer rate (amplitude ratio) of Z-direction is

$\mathrm{\η}=\frac{\sqrt{1+{\left(2\mathrm{\ξ\λ}\right)}^2}}{\sqrt{{(1-{\mathrm{\λ}}^2)}^2+{\left(2\mathrm{\ξ\λ}\right)}^2}}---\left(3\right)$

Wherein, damping ratio frequency ratio λ=2 π f/ ω _n, natural frequency

According to formula (3), can obtain the relation curve between η and ξ, λ, as shown in Figure 5:

As can be seen from Figure 5, when time, η < 1, system has vibration isolating effect, and along with the increase of λ, vibration isolating effect improves constantly, and just means the rigidity that will reduce system, thereby can reduce stability and the antijamming capability of system but increase λ; In λ > 5 regions, the variation of η not obvious, then the value that increases λ will can significantly not improve vibration isolating effect, therefore choose λ=2～4.5.When time, along with the increase of ξ, resonance peak is more and more less; And work as time, increase along with ξ, η increases on the contrary, vibration isolating effect reduces, due to vibration isolator in real work except isolating the impact of simple harmonic oscillation, also want the impact of shock isolation, for avoiding impacting, make to be produced excessive amplitude and resonance by device for vibration insutation, just must increase ξ and cut down resonance peak, for solving above-mentioned contradiction, choose ξ=0.1～0.3.

So by

$2\&le;\mathrm{\&lambda;}=\frac{2\mathrm{\&pi;f}}{{\mathrm{\&omega;}}_n}=\frac{2\mathrm{\&pi;f}}{\sqrt{\frac{n}{3}{\mathrm{\&sigma;}}_k^{2}k/m}}\&le;\mathrm{4.5,0.1}\&le;\mathrm{\&xi;}=\frac{\frac{n}{3}{\mathrm{\&sigma;}}_c^{2}c/m}{2\sqrt{\frac{n}{3}{\mathrm{\&sigma;}}_k^{2}k/m}}\&le;0.3$

Just can obtain the elasticity that makes system all can effectively isolate the above medium-high frequency vibration of fHz on three-dimensional, the parameter of damping member

$\frac{16}{27}\frac{m{\mathrm{\&pi;}}^2{f}^2}{n{\mathrm{\&sigma;}}_k^2}\&le;k\&le;3\frac{m{\mathrm{\&pi;}}^2{f}^2}{n{\mathrm{\&sigma;}}_k^2},\frac{3}{5}\frac{\mathrm{m\&pi;f}}{n{\mathrm{\&sigma;}}_c^2}\&le;c\&le;\frac{4}{5}\frac{\mathrm{m\&pi;f}}{n{\mathrm{\&sigma;}}_c^2}$

Design and the calculation procedure of n-TRRT series vibration isolator in parallel

(1) determine airborne photoelectric platform (comprising moving platform) gross mass m, by the overall geometry size of photoelectric platform, determined the distribution circle radius r of T pair on moving, fixed platform _m, r _b, and the vibration frequency range that need to isolate of given three-dimensional (rb>rm).

(2) determine minute number n, the work equilibrium position of vibration isolator length of connecting rod l, meet determine the mounting point parameter σ of elasticity, damping member _k, σ _c.

(3) determine the parameter of elasticity, damping member

$\frac{16}{27}\frac{m{\mathrm{\&pi;}}^2{f}^2}{n{\mathrm{\&sigma;}}_k^2}\&le;k\&le;3\frac{m{\mathrm{\&pi;}}^2{f}^2}{n{\mathrm{\&sigma;}}_k^2},\frac{3}{5}\frac{\mathrm{m\&pi;f}}{n{\mathrm{\&sigma;}}_c^2}\&le;c\&le;\frac{4}{5}\frac{\mathrm{m\&pi;f}}{n{\mathrm{\&sigma;}}_c^2}$

Irrotational displacement isolation mounting in the utility model has four large outstanding features: 1, without corner, move; 2, when work equilibrium position, the inertia of system, rigidity and damping be all identical and decoupling zeros in three directions, and work equilibrium position is with the change of side chain number, is easy to determine; 3, all joints are revolute joint, simple and compact for structure, and reliability is high; 4, elasticity, damping member are easy to arrange.Based on above feature, this irrotational displacement isolation mounting is applied to, in the middle of the medium-high frequency vibration isolation of vehicle-mounted or airborne photoelectric platform, mainly contain the advantage of four aspects: 1. can avoid the impact of angular vibrations on optical system image quality; 2. can avoid vibration to cause that photoelectric platform rotates and cause photoelectric platform system of coordinates to rotate with respect to vehicle or aircraft system of coordinates, and then reduce to have the measurement error of the photoelectric platform of measurement function; 3. can greatly reduce the complexity of system and calculating; 4. can greatly reduce the manufacture cost of system, improve system reliability, reduce the shared space of system.So this patent has important use value.

In other embodiment of this irrotational displacement isolation mounting: the number of side chain can also be two, three, five or other number; Certainly in each side chain, also elastic element or damping member can be only set; Elasticity, damping member can independently arrange (as described in above-described embodiment), also can choose mixing elastic damping element, such as metal-rubber; Distance and the distance between the axis of the 6th revolute pair and the axis of the 3rd revolute pair between the axis of the axis of the second revolute pair and the 6th revolute pair can also be not identical.

The embodiment of side chain is as shown in Fig. 1～4: the concrete structure of side chain is identical with the side chain described in above-mentioned each irrotational displacement isolation mounting, is not described in detail in this.

Claims (10)

1. the side chain of irrotational displacement isolation mounting, it is characterized in that: comprise orthogonal the first revolute pair of axis and the second revolute pair, also comprise orthogonal the 3rd revolute pair of axis and the 4th revolute pair, second, the axis of the 3rd revolute pair is parallel to each other, first, the axis of the 4th revolute pair is parallel to each other, side chain also comprises the 5th revolute pair and the 6th revolute pair that axis parallels with the second revolute pair, the second revolute pair, the 6th revolute pair, between the 3rd revolute pair and the 5th revolute pair, pass through in turn first connecting rod, second connecting rod, third connecting rod is connected with the 4th connecting rod, the axis place plane parallel of the axis place plane of the axis of the second revolute pair and the 6th revolute pair and the axis of the 3rd revolute pair and the 5th revolute pair.

2. the side chain of irrotational displacement isolation mounting according to claim 1, is characterized in that: the distance between the axis of the axis of the second revolute pair and the 6th revolute pair is identical with the distance between the axis of the 6th revolute pair and the axis of the 3rd revolute pair.

3. the side chain of irrotational displacement isolation mounting according to claim 1, is characterized in that: between described third connecting rod and the 4th connecting rod, be provided with elastic element.

4. the side chain of irrotational displacement isolation mounting according to claim 3, is characterized in that: described elastic element is identical with the distance between the distance between the axis of described the 5th revolute pair and the tie point between described elastic element and third connecting rod and the axis of described the 5th revolute pair with the tie point between the 4th connecting rod.

5. according to the side chain of the irrotational displacement isolation mounting described in claim 1～4 any one, it is characterized in that: between described first connecting rod and second connecting rod, be provided with damping member.

6. irrotational displacement isolation mounting, comprise moving platform and fixed platform, it is characterized in that: moving, between fixed platform, be provided with at least two side chains that structural type is identical, described side chain comprises orthogonal the first revolute pair of axis, orthogonal the 3rd revolute pair of the second revolute pair and axis, the 4th revolute pair, the first revolute pair is connected with moving platform, the 4th revolute pair is connected with fixed platform, second, the axis of the 3rd revolute pair is parallel to each other, first, the axis of the 4th revolute pair is parallel to each other, each side chain also comprises the 5th revolute pair and the 6th revolute pair that axis parallels with the second revolute pair, the second revolute pair, the 6th revolute pair, between the 3rd revolute pair and the 5th revolute pair, pass through in turn first connecting rod, second connecting rod, third connecting rod is connected with the 4th connecting rod, the axis place plane parallel of the axis place plane of the axis of the second revolute pair and the 6th revolute pair and the axis of the 3rd revolute pair and the 5th revolute pair.

7. irrotational displacement isolation mounting according to claim 6, is characterized in that: the distance between the axis of the axis of the second revolute pair and the 6th revolute pair is identical with the distance between the axis of the 6th revolute pair and the axis of the 3rd revolute pair.

8. irrotational displacement isolation mounting according to claim 6, is characterized in that: between described third connecting rod and the 4th connecting rod, be provided with elastic element.

9. irrotational displacement isolation mounting according to claim 8, is characterized in that: described elastic element is identical with the distance between the distance between the axis of described the 5th revolute pair and the tie point between described elastic element and third connecting rod and the axis of described the 5th revolute pair with the tie point between the 4th connecting rod.

10. according to the irrotational displacement isolation mounting described in claim 6～9 any one, it is characterized in that: it is characterized in that: between described first connecting rod and second connecting rod, be provided with damping member.