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

The invention discloses a piezoelectric active vibration isolating mechanism which comprises a first force sensor, a spring corrugated pipe, an intermediate mass block, a first flexible hinge, a piezoelectric actuator, a second force sensor, a second flexible hinge and a controller. One end of the first force sensor is connected with a base platform, and the other end of the first force sensor is sequentially connected with the second force sensor, the spring corrugated pipe, the intermediate mass block, the second flexible hinge, the piezoelectric actuator and the first flexible hinge. The first force sensor and the second force sensor are respectively used for detecting the vibrating signals of the base platform and the vibrating signals of a load platform and can respectively transmit the detecting vibrating signals to the controller, and the controller can control the piezoelectric actuator to exert acting force on the load platform to compensate the load platform. By means of a two-stage serial-connection suspending structure, the inherent frequency of the structure is effectively reduced, and micro-vibration low-frequency interference in precision equipment can be effectively restrained.

A nozzle plate and an atomizing module using the nozzle plate are disclosed. The atomizing module is installed at a cavity and includes a piezoelectric circular plate, a braking circular plate and a nozzle plate. The braking circular plate is installed on a side of the piezoelectric circular plate. The nozzle plate is a circular disc clamped between the piezoelectric circular plate and the braking circular plate, and the nozzle plate includes firing holes and first protrusions. Each first protrusion is non-circular and protruded in a direction towards the piezoelectric circular plate or the braking circular plate to form a multi-curved surface structure radially or circularly arranged into a specific geometric pattern. The nozzle plate can increase the atomizing area, atomizing quantity and liquid-gas exchange rate to prevent excessive stresses from concentrating at the center of the nozzle plate or vibrations from cracking or breaking the nozzle plate.

The invention discloses a device and a method for monitoring the tool state in a cutting process and chip formation. The device comprises a tool and an AE signal collector which are mounted on a toolholder, a workpiece, a test platform and a data acquisition system, wherein the tool holder includes a main clamp holder, a sub-clamp-holder and a heat-insulating damping pad, the tool and the heat-insulating damping pad are arranged side by side between the main clamp holder and the sub-clamp-holder, the sub-clamp-holder is locked on the main clamp holder in the forward direction through connecting bolts penetrating through the heat-insulating damping pad, the sub-clamp-holder reversely and tightly abuts against the main clamp holder through an adjusting bolt, and the AE signal collector is mounted on the sub-clamp-holder; and a first piezoelectric force transducer is arranged on the flank surface of the tool, a second piezoelectric force transducer is arranged on the rake face of the tool, a surface strain meter is mounted on the main clamp holder, and a high speed CCD camera is mounted above the tool. According to the device and the method for monitoring the tool state in the cutting process and the chip formation, AE signal has high acquisition precision, good independence and high relevance.

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.

A compressor for natural gas is made in a format suitable for mounting on a wall or upright support at a residential location to permit refilling of the gas reservoir of a gaseous-fueled motor vehicle parked at the residence. The wall-mounted appliance has vibration isolation supports to minimize transmission of noise into the residence. It has a ventilation and air circulation system that allows it to test for the presence of flammable gas both leaking from the appliance and present in the adjacent ambient environment, e.g. a garage. A motor speed control system permits operation of the appliance at speeds which are reduced when approaching the final pressure for the motor vehicle reservoir and at speeds which avoid the natural resonant frequencies of the system.

The invention discloses an orifice piece and an atomization assembly with the same. The atomization membrane assembly is arranged on a cavity and comprises a piezoelectric ring piece, a brake ring piece and the orifice piece, wherein the brake ring piece is arranged on one side of the piezoelectric ring piece; the orifice piece is disc-shaped, clamped between the piezoelectric ring piece and the brake ring piece and provided with a plurality of triggering holes and first upheaval parts; and the plurality of first upheaval parts are non-circular and protrude and stretch convexly towards the direction of the piezoelectric ring piece or the brake ring piece to form a multi-curve structure arranged in a radiation or ring shape with a specific geometric modeling pattern. Therefore, the orifice piece can be used for enlarging the atomization region and improving the atomization quantity and the liquid-gas exchange efficiency, and can be prevented from being cracked since stress is excessively concentrated at the center of the orifice piece during vibration.

A ring gear (82) of a planetary gear speed reducer (80) is fixed to a casing (31) provided with a core metal (31) fixed to a vehicle panel via a rubber damper (92). Therefore, the driving unit can be reduced in size through adoption of a speed reducer (80) formed of gears (82) made of spur gears, and the rubber dumper (92) can suppress low frequency vibrations which are transmitted from the speed reducer (80) to the vehicle panel. Therefore, the vehicle body of the vehicle having a low characteristic frequency is prevented from resonating with the incoming low frequency vibrations to generate noises which are transmitted to the vehicle interior, and which give an occupant an unpleasant feeling.

The invention relates to the technical field of engineering structure vibration reduction, in particular to a double-layer pyramid type light vibration reduction metamaterial lattice structure. The metamaterial lattice structure is composed of unit cells arranged in a two-dimensionally periodic manner, and the unit cells are generatively designed based on a double-layer pyramid type lattice structure. Each unit cell comprises an upper panel, a lower panel, eight double-layer pyramid type sandwich round bars arranged between upper panel and the lower panel, and a spherical resonance unit embedded in the intersection point of the eight double-layer pyramid type sandwich round bars, wherein the upper panel, the lower panel, the double-layer pyramid type sandwich round bars and the spherical resonance unit are all made of a glass fiber reinforced (GFR) nylon material. By embedding the periodically arranged round resonance units into the double-layer pyramid type light vibration reduction metamaterial lattice structure to generate a broadband gap, the purpose of vibration reduction is achieved; and the structure has the advantages of integrating light weight and vibration reduction functions, having a wide vibration reduction frequency range, being easy to manufacture, having good bearing capacity, avoiding changing of the external geometrical characteristics of the structure and the like.

The invention discloses a leveling device and leveling method of a photoetching machine projection objective. The leveling device comprises a workbench, a hanging frame, a hanging frame support, an installation base plate, an objective frame, a photoelectric measurement system, a projection objective, a sensor measurement system, an active damper, a vertical adjustment mechanism and a controller, wherein the hanging frame is used for supporting the workbench, the hanging frame support is used for supporting the hanging frame, the installation base plate is arranged above the hanging frame support, the objective frame is arranged on the installation base plate, the photoelectric measurement system and the projection objective are arranged on the objective frame, the sensor measurement system is connected with a surface of the objective frame, the active damper is arranged on the installation base plate and is connected with the objective frame, the vertical adjustment mechanism is arranged below the active damper, and the controller is electrically connected with the sensor measurement system, the active damper and the vertical adjustment mechanism. By the leveling device, the purpose that the projection objective and the photoelectric measurement system are free from influence of external vibration and impact is achieved, meanwhile, the projection objective and the photoelectric measurement system are maintained in a static state relative to the position of the hanging frame of a support workpiece table all the way, the exposure imaging quality of the projection objective and the detection performance of the photoelectric measurement system are improved.

The invention discloses a nickel-titanium shape memory alloy capable of simultaneously realizing the functions of energy absorption and vibration reduction, and a preparation method and application thereof, and relates to the technical field of NiTi shape memory alloys. A cold-deformed nickel-rich NiTi alloy is used for preparing a hand-shaped structure with a negative poisson ratio characteristic, and the phase change behavior and mechanical property of the NiTi alloy are regulated and controlled through heat treatment to a cold-deformed nickel-rich NiTi alloy component. Thus, stress-inducedmartensitic transformation occurs to the NiTi alloy component in the impact deformation process, and large impact energy is absorbed. The deformed NiTi alloy component is kept in a martensite state, and energy dissipation is promoted due to interaction between martensite variants, so that the component has higher damping performance after completion of impact, and a good damping effect is achieved.

The invention relates to the technical field of engineering structure vibration reduction, in particular to a low-frequency vibration reduction light metamaterial lattice structure and a manufacturingmethod thereof. The metamaterial lattice structure is composed of two-dimensional periodically-arranged unit cells, and each unit cell comprises a base structure and a cuboid resonance unit embeddedinto the base structure, wherein the base body structure comprises an upper panel, a lower panel and an internal pyramid-shaped sandwich structure, the cuboid resonance units are located in the internal pyramid-shaped sandwich structure, each unit is composed of an upper part and a lower part, the upper part is made of a hard metal material, and the lower part is made of a glass fiber reinforced (GFR) nylon material. According to the invention, a broadband gap in a low-frequency range is generated by designing periodically arranged resonance unit structures, so that the purpose of efficient vibration reduction is achieved. The vibration damper has the characteristics that the bearing and vibration damping functions are integrated, the vibration damping frequency range is wide, the externalgeometrical characteristics of the structure are not changed, and the structure vibration can be effectively suppressed in a low-frequency range.

The invention discloses a parallel type internal and external combined shock absorber, and belongs to the technical field of auto parts. The parallel type internal and external combined shock absorber comprises an upper base plate, a lower base plate and a shock absorption body, wherein the shock absorption body comprises an external connection shock absorption mechanism and an internal connection shock absorption mechanism; the external connection shock absorption mechanism comprises a small-diameter pressure spring, a medium-diameter tension spring and a large-diameter pressure spring which jointly form a tandem type large-small-diameter tension-compression spring, and a small-diameter frame cylinder and a large-diameter frame cylinder are inserted into the tandem type large-small-diameter tension-compression spring in a sleeving mode to form the external connection shock absorption mechanism; the internal connection shock absorption mechanism is formed by sequentially connecting a first damper, a first inerter, a second inerter and a second damper in series; and the internal connection shock absorption mechanism is sleeved with the external connection shock absorption mechanism to form the shock absorption body, and the shock absorption body is fixedly connected between the upper base plate and the lower base plate to form the parallel type internal and external combined shock absorber. The parallel type internal and external combined shock absorber has the beneficial effects that the vibration frequency can be mixed, the frequency and the amplitude are induced to be converted, the vibration is converted into low-frequency vibration, the vibration in the running process of the automobile is continuously reduced, and the riding comfort of the automobile is improved.

The invention provides an adaptive backstepping sliding-mode active vibration isolation control method for a flexible spacecraft. The method comprises representing the dynamic equation of a Stewart vibration isolation platform by a Newton-Euler method; using a voice coil motor as an actuator to give the decoupled dynamic equation of the Stewart vibration isolation platform; designing a backstepping sliding-mode controller by combining a backstepping method with sliding-mode control; and for the case where the upper boundary of external disturbance is unknown, adding adaptive control to the active vibration isolation control by using the characteristics of adaptive control so as to design an adaptive backstepping sliding-mode controller. The adaptive backstepping sliding-mode active vibration isolation control method has a good active vibration isolation control effect, especially in the case where the vibration amplitude is unknown.

The invention discloses a spatial six-degree-of-freedom magnetic suspension vibration isolation platform, and belongs to the technical field of space payload vibration isolation. According to the platform, the problems that an existing magnetic suspension platform is large in occupation space, complex in structure and low in integration degree are solved. Four coil arrays are correspondingly located between four upper permanent magnet arrays and four lower permanent magnet arrays, a connecting cylinder penetrates an area defined by the four coil arrays, each permanent magnet array comprises apermanent magnet with a horizontal magnetic pole direction and a permanent magnet with a vertical magnetic pole direction, and during operation, the coil arrays receive an Lorentz force effect in thehorizontal direction and the vertical direction in a magnetic field generated by the upper permanent magnet arrays and the lower permanent magnet arrays, and control over motion in the horizontal direction and the vertical direction is achieved. By utilizing electromagnetic drive, six-degree-of-freedom actions can be achieved. The mechanism is quick in response, easily realizes high-precision control, and effectively suppresses low-frequency vibration. The structure is less in component, simple in structure, high in integration degree, small in occupied space, light in product weight and easyto disassemble and maintain.

The invention discloses a local resonance type vibration isolation system for low-frequency vibration reduction of a precise instrument. The local resonance type vibration isolation system comprises asimply supported beam and the precise instrument mounted on the simply supported beam, and the precise instrument is mounted on the upper surface of the simply supported beam in a vibration isolationmanner; M local resonance cells are further periodically arranged on the upper surface of the simply supported beam in the axial direction, and each local resonance cell comprises N vibration absorbers; and M*N vibration absorbers are arranged at equal intervals, and the precise instrument is arranged between any two adjacent vibration absorbers. According to the local resonance type vibration isolation system, low-frequency vibration of the precise instrument can be effectively restrained, the local resonance type vibration isolation system is composed of local resonance cells arranged on the beam and the precise instrument, the local resonance cells comprise a plurality of different vibration absorbers, and therefore the effective vibration reduction range and the vibration reduction efficiency of the vibration absorbers can be greatly improved, and an excellent low-frequency vibration isolation effect is achieved; and the system is simple in structure and convenient to machine, install and maintain in the later period, and the application cost is reduced.

The invention discloses a static pressure air floatation supporting device with an extrusion film assisting in pressure stabilization. The static pressure air floatation supporting device comprises an air supply device, a floating body and a carrier, wherein the floating body and the carrier are oppositely arranged, and the air supply device introduces air flow between the floating body and the carrier to form a static pressure bearing air film between the floating body and the carrier. The static pressure air floatation supporting device further comprises a high-frequency vibration generator mounted on the carrier, and the high-frequency vibration generator drives the carrier to vibrate at high frequency. According to the static pressure air floatation supporting device, the effect of restraining low-frequency vibration of the static pressure bearing air film can be achieved, it can be further avoided that the floating body generates resonance along with the static pressure bearing air film, and then the stability of air floatation bearing resonance is improved.