31results about How to "Suppression of low frequency vibration" patented technology

A piezoelectric active vibration isolation mechanism comprises a first force sensor (23b), a spring bellows (27), a middle mass block (26), a first flexible hinge (22b), a piezoelectric actuator, a second force sensor (23a), a second flexible hinge (22a) and a controller, one end of the first force sensor (23b) being used for connecting a base platform (28), and the other end thereof being connected sequentially to the spring bellows (27), the middle mass block (26), the first flexible hinge (22b), the piezoelectric actuator, the second force sensor (23a) and the second flexible hinge (22a). The first force sensor (23b) and the second force sensor (23a) are respectively used for detecting vibration signals of the base platform (28) and of a loading platform (21), and respectively transmitting the detected vibration signals to the controller so that the controller controls the piezoelectric actuator to apply a force onto the loading platform (21), thereby compensating the loading platform (21). The piezoelectric active vibration isolation mechanism utilizes a two-stage series-connected suspension structure, effectively reducing the inherent frequency of the structure and being able to effectively suppress low-frequency interference of the slight vibration in a precision device. A method of reducing the inherent frequency of a vibration system is further disclosed.

The invention discloses a platform and a method of main and passive vibration isolation in space six-degree of freedom based on electromagnetic negative stiffness. The platform comprises a load platform, a foundation platform and six electromagnetic negative stiffness vibration isolators, wherein the six electromagnetic negative stiffness vibration isolators are fixed between the load platform andthe foundation platform through a connecting piece; the two adjacent vibration isolators are perpendicular to each other in the axial direction, and the load platform has six-degree of freedom relative to the foundation platform; each electromagnetic negative stiffness vibration isolator comprises an actuating rod, an upper shell, a lower shell, a combined disc spring, a base, a bottom supportingrod and two sets of excitation devices, wherein the actuating rod is fixedly connected with the upper shell through a cross beam spring piece, a strain sensor is pasted on the cross beam spring piece, and is used for detecting the axial displacement of the actuating rod; each vibration isolator can realize active control of equivalent electromagnetic negative rigidity, so that the vibration isolation platform is of a positive and negative stiffness parallel structure in six-degrees of freedom, the vibration isolators have relatively low resonance frequency and a very wide vibration isolationfrequency band, so that micro-vibrations in the space six-degree of freedom direction can be effectively inhibited. According to the platform and the method, the platform and the method of the main and passive vibration isolation in the space six-degree of freedom based on the electromagnetic negative stiffness are suitable for equipment micro-vibration main and passive vibration isolation in thefield of spaceflight aviation, precise instruments and the like.

The invention discloses a large-scale flexible spacecraft vibration suppression method based on a floating-base Stewart platform, which belongs to the field of spacecraft dynamics and control research, and specifically relates to a floating-base Stewart platform for large-scale flexible spacecraft dynamics modeling method with flex vibration suppression. Compared with the traditional fixed-base Stewart platform, the present invention adopts the dynamic model of the floating-base Stewart platform, which can more accurately describe the attitude motion-flexible vibration coupling relationship of the overall spacecraft, and can be more conveniently applied to space spacecraft. The strut dynamics modeling takes into account the influence of the mass and inertia of the additional active drive itself; using the large-deformation geometric nonlinear rigid-flexible coupling theory, the coupled dynamics of a space-based large-scale flexible spacecraft based on the Stewart platform including thermal loads is established state space model.

The invention discloses a space six-degree-of-freedom magnetic suspension vibration isolation platform, which belongs to the technical field of space payload vibration isolation. The invention solves the problems that the existing magnetic levitation platform occupies a large space, has a complicated structure and low degree of integration. The four coil arrays are correspondingly located between the four upper permanent magnet arrays and the four lower permanent magnet arrays, and the connecting cylinder is set in the enclosed area of ​​the four coil arrays. Each permanent magnet array includes permanent magnets and magnetic poles with a horizontal magnetic pole direction. Permanent magnets with a vertical direction, when working, the coil array receives the Lorentz force in the horizontal and vertical directions in the magnetic field generated by the upper permanent magnet array and the lower permanent magnet array, and realizes horizontal and vertical movement control. Using electromagnetic drive, six degrees of freedom can be realized. The mechanism responds quickly, easy to realize high-precision control, and effectively suppresses low-frequency vibration. There are few structural components, simple structure, high degree of integration, relatively small footprint, light weight and easy disassembly and maintenance.

The present invention relates to the technical field of engineering structure vibration reduction, in particular to a double-layer pyramid light-weight vibration-damping metamaterial lattice structure, the metamaterial lattice structure is composed of two-dimensional periodically arranged unit cells, and the unit cells are based on double Derivative design of layered pyramid-shaped lattice structure, including upper and lower panels, 8 double-layer pyramid-shaped sandwich rods arranged between the upper and lower panels, and spherical resonance units embedded in the intersection of 8 double-layer pyramid-shaped sandwich rods , the upper and lower panels, the double-layer pyramid-shaped sandwich rod, and the spherical resonance unit are all made of glass fiber reinforced (GFR) nylon material. The present invention generates a broadband bandgap by embedding periodically arranged circular resonant units in a double-layer pyramid light-weight vibration-damping metamaterial lattice structure, thereby achieving the purpose of vibration reduction. The structure has light weight-vibration reduction functions integrated It has the characteristics of low vibration, wide frequency range of vibration reduction, easy manufacture, good bearing capacity, and does not change the external geometric characteristics of the structure.

The invention provides a shear type damping tube having a vibration damping performance and a vibration damping adapter. The shear type damping tube comprises an aluminum alloy joint, a carbon fiber tube, a damping glue layer, an aluminum alloy bushing and a steel spring tube, wherein the upper section of the carbon fiber tube is in bonding connection with the aluminum alloy joint; the outer side of the lower section of the carbon fiber tube is connected with the inner side of the aluminum alloy bushing through the damping glue layer; the inner side of the lower section of the carbon fiber tube is in bonding connection with the outer side of the steel spring tube; and the aluminum alloy bushing is connected with the steel spring tube. Compared with the prior art, the vibration damping adapter, produced by the shear type damping tube having the vibration damping performance, has excellent vibration damping performance to restrain low-frequency vibration of satellite effective load of an active flight section of a carrying rocket, and has better rigidity to improve the mechanical environment of the satellite effective load at the active flight section of the rocket when being used for connecting the carrier rocket with a satellite.

The invention discloses an integral metal spring type active vibration reduction table. The integral metal spring type active vibration reduction table comprises a bottom plate (10) and an upper panel (60). Passive vibration isolation units and active vibration isolation units are arranged at the four corners of the bottom plate (10) correspondingly. The passive vibration isolation units are used for achieving high-frequency attenuation of the vibration reduction table and each comprise a metal spring assembly, vibration isolation rubber (50) and a structural damper. The active vibration isolation units are used for achieving active control over the vibration reduction table and each comprise a feedback speed sensor, a feedforward speed sensor, a Lorentz motor and a controller. According to the vibration reduction table, the vibration reduction technique combining passive vibration isolation with active vibration reduction is adopted, high-frequency vibration can be isolated comprehensively, low-frequency vibration can be effectively restrained, and the transmission rate of low-frequency vibration is ensured; and meanwhile, high attenuation rate of high-frequency vibration is achieved, full decoupling under six-degree of freedom control can be achieved, and application is flexible.

The invention discloses a vibration suppression method utilizing the rotation of the root of a flexible component, which can quickly suppress the vibration of the flexible component without greatly increasing the complexity of the system. First, according to the mass parameters of the satellite and the modal analysis results of the flexible part, a dynamic model of the satellite with flexible rotating parts is established. Next, the root of the flexible component suppresses the flexural vibration through the rotation angular acceleration, and feeds back the rotation angle and angular velocity of the component itself, so as to avoid excessive rotation angle and angular velocity of the flexible component root. Finally, in the attitude control of the satellite body, the disturbance generated by the root motion of the flexible component is compensated to ensure the high-precision control of the satellite body. The method proposed by the invention can quickly suppress the low-order vibration of the flexible component, and at the same time, the rotational motion of the root of the flexible component converges, avoiding the impact on the orientation of the component. In addition, the additional disturbance caused by the rotation of the root of the flexible component is compensated to reduce the influence on the control of the satellite body.