312 results about "Negative stiffness" patented technology

The invention relates to a low-frequency vibration isolator with a wide quasi-zero stiffness interval. The low-frequency vibration isolator comprises a bearing platform, a base, a first negative stiffness assembly, a second negative stiffness assembly and a linear vibration isolation assembly. The bearing platform and the base are arranged in parallel and are both provided with bolt holes and limiting holes; a linear vibration isolation assembly is installed between the bearing platform and the base. The first negative stiffness assemblies are symmetrically distributed with the center point connecting line of the bearing platform and the base as the symmetry axis. The top of the first negative stiffness assembly is connected with the bearing platform, and the bottom of the first negative stiffness assembly is connected with the base. The two ends of the second negative stiffness assembly are connected with the two first negative stiffness assemblies correspondingly. The low-frequency vibration isolator has the characteristics of high static rigidity and low dynamic rigidity, the contradiction between the bearing capacity and the vibration isolation performance of a linear vibration isolation system is effectively solved, and the effective low-frequency vibration isolation effect on a vibration-isolated object is achieved while the bearing capacity of the vibration isolator is guaranteed.

The invention provides a quasi-zero-stiffness base and an adjustable quasi-zero-stiffness local resonance super-structure vibration isolation device, belongs to the field of environmental vibration reduction and isolation in traffic engineering and civil engineering, and aims at solving the problems that in the prior art, a spring quasi-zero-stiffness structure is complex in installation structure and poor in structural stability. The device comprises a bottom plate, a plurality of first beams with a positive stiffness effect, a plurality of second beams with a negative stiffness effect and a plurality of regular triangular prisms, the first beam, the second beam, the regular triangular prism and the bottom plate are integrally formed, on one hand, it is ensured that all connecting pieces are in rigid connection, the situation that connecting points affect the stability of the structure is avoided, on the other hand, the assembling process can be simpler, and the assembling efficiency is improved.

The invention relates to the technical field of structural engineering shock isolation, in particular to a quasi-zero stiffness shock isolation device based on hydraulic negative stiffness and a design method thereof. A quasi-zero stiffness shock isolation device based on hydraulic negative stiffness comprises a vertical bearing unit which comprises at least one vertical spring, and the two ends of the vertical spring are connected to the top face of a lower connecting plate and the bottom face of an upper connecting plate respectively; the negative stiffness unit comprises a hydraulic oil cylinder and a piston rod, the piston rod extends into the hydraulic oil cylinder, and the hydraulic oil cylinder and the piston rod are hinged to the lower connecting plate and the upper connecting plate respectively, or the hydraulic oil cylinder and the piston rod are hinged to the upper connecting plate and the lower connecting plate respectively; the distance between the upper connecting plate and the lower connecting plate is increased or decreased to drive the length of the piston rod extending into the hydraulic oil cylinder to change so as to provide negative stiffness. The problems that in the prior art, when a nonlinear vibration isolation system provides negative stiffness in a metal horizontal spring compensation mode, a quasi-zero stiffness working zone is narrow, the bearing capacity is low, and the requirement for installation precision is high are solved.

The invention discloses a disc type negative stiffness damper which comprises a base plate, a sliding block is fixedly installed on the base plate, and a rack-shaped sliding rail is horizontally installed on the sliding block in a sliding mode. A large gear and a small gear are rotationally installed on the base plate through a supporting structure, one position of the large gear is externally meshed with the small gear, the other position of the large gear is externally meshed with a rack on the sliding rail, the center of the small gear is fixedly connected with a small gear shaft, and a damper is further fixedly connected to the small gear shaft. A first connecting piece is arranged on the edge of the large gear, a second connecting piece is arranged on the base plate, the first connecting piece is connected with one end of a pretension spring, the other end of the pretension spring is connected with the second connecting piece, and the first connecting piece, the second connecting piece and the pretension spring form a negative stiffness mechanism. The negative stiffness effect is generated by the pre-tensioning spring, and compared with a pre-pressing spring, the pre-tensioning spring cannot be bent; and meanwhile, compared with the magnetic negative stiffness, the magnetic negative stiffness has a larger stroke.

Disclosed are an intelligent vibration isolator and a control method thereof. The intelligent vibration isolator includes a base, a vibration isolation mechanism disposed inside the base, and a controller; the base includes a bottom plate and a supporting sleeve disposed on the bottom plate; the vibration isolation mechanism includes a load platform, a supporting platform, a magnetorheological elastomer and an electromagnet which are sequentially and coaxially disposed from top to bottom; the vibration isolation mechanism is provided with at least three negative stiffness mechanisms that are uniformly distributed in a circumferential direction of the supporting platform; a strain detection device is disposed on an outer wall of the magnetorheological elastomer; and the controller adjusts and controls a magnitude of current of the electromagnet according to a received strain magnitude to control vertical stiffness of the isolator, and make the intelligent vibration isolator always be in a quasi-zero stiffness state.

The invention belongs to the technical field of mechanical transmission systems, and particularly discloses a method and a system for calculating, regulating and controlling the vibration isolation rate of a rigidity-variable magnetic torsional vibration buffer, and the method comprises the following steps: obtaining a real-time working condition, modeling a single permanent magnet magnetic field by adopting an equivalent magnetic charge method, and calculating the vibration isolation rate of the rigidity-variable magnetic torsional vibration buffer; a magnetic block negative stiffness model and a spring torsion sheet positive stiffness model of the annular Halbach array are constructed, the total coupling stiffness is calculated, the vibration isolation effect of the magnetic torsional vibration buffer is solved, vibration suppression effects and resonance interval distribution under different working conditions are obtained, and based on the vibration isolation effect of the magnetic torsional vibration buffer, the vibration suppression effect of the magnetic torsional vibration buffer is calculated. The gap adjustable mechanism adjusts the rigidity of the spring torsion sheet and the gap of the magnetic ring in real time. By the adoption of the technical scheme, the gap between the inner magnetic ring and the outer magnetic ring is flexibly set according to multi-working-condition requirements, so that applicability and reliability are improved, and low-frequency torsional vibration is effectively restrained while efficient torque transmission is ensured.

The invention discloses an ultrasonic robot tail end zero-rigidity constant-force driver and a control method thereof.The ultrasonic robot tail end zero-rigidity constant-force driver comprises a shell, a negative-rigidity structure, a positive-rigidity structure and a control circuit board, the shell comprises an external main frame, a top cover and a base, the negative-rigidity structure comprises a fixed magnet and a movable magnet set, and the positive-rigidity structure comprises a positive-rigidity structure and a negative-rigidity structure; the fixed magnet is fixedly installed on the base, the movable magnet set is fixedly installed on the top cover, the positive stiffness structure comprises a linear servo motor, a displacement sensor, a linear spring and a spring seat, the movable magnet set and the fixed magnet generate negative stiffness through magnetic field interaction, and the linear spring generates positive stiffness through deformation. And the resultant forces are offset to realize zero-rigidity constant-force output. The control circuit board is installed in the base and electrically connected with the linear servo motor and the displacement sensor. The method is used for solving the problems that in the prior art, scanning efficiency is low, the method is sensitive to measurement errors, and ultrasonic scanning requirements of complex scenes are difficult to meet.

The invention relates to the technical field of structural vibration control, in particular to an adjustable electric damping-negative stiffness dynamic vibration absorber for a flexible shafting. According to the technical scheme, the damping device comprises a support and a rolling bearing, a plurality of first supporting rods used for supporting are arranged outside the rolling bearing, an electric damper used for absorbing vibration is arranged at one end of each first supporting rod, and a second supporting rod used for supporting is arranged on the other side, away from the first supporting rods, of each electric damper. A negative stiffness vibration absorber is arranged at the end, away from the electric damper, of the second supporting rod, and the electric damper comprises an auxiliary circular ring used for bearing loads. Through the arrangement of the adjusting plate, the adjusting bolt, the disc spring, the mass block, the movable magnet, the static magnet and the electric damper, the purposes of vibration absorption and vibration reduction can be achieved at the transcritical rotating speed and the supercritical working rotating speed, and the negative stiffness dynamic vibration absorption frequency and the electric damping suppression modal frequency can be rapidly adjusted according to the change of the operation working condition; and the application range and the universality are improved.

The invention provides an electromagnetic quasi-zero stiffness vibration isolator and a control method, and belongs to the technical field of vibration isolation. The vibration isolator comprises a base, a positive stiffness mechanism, a negative stiffness mechanism, a positive and negative stiffness connecting mechanism and a dynamic control module. The positive stiffness mechanism adopts a hydraulic spring to provide basic positive stiffness; the negative stiffness mechanism comprises a plurality of stator units distributed on the base in an annular array and a rotor suspended in the center of a magnetic field of the stator units, and is used for generating nonlinear negative stiffness; the top end of the hydraulic spring supports a load through the bearing table and keeps a preset gap with the inner wall of the rotor; the positive and negative stiffness connecting mechanism realizes displacement transmission and cooperative adjustment; the dynamic control module comprises a displacement sensor and a controller, the sensor collects displacement signals, and the controller adjusts excitation currents of the stator units according to the signals and dynamically adjusts electromagnetic force, so that the vibration isolator is kept in a quasi-zero stiffness state. The quasi-zero stiffness state can be still kept when the load changes, load self-adaption low-frequency vibration isolation is achieved, and the system stability and the vibration isolation performance are improved.

The self-adaptive anti-lifting device based on negative stiffness compensation comprises a friction pendulum shock insulation support and a negative stiffness compensation assembly, the friction pendulum shock insulation support comprises a first seat plate, a spherical crown body and a second seat plate, and the negative stiffness compensation assembly comprises an upper structure connecting plate, a rigid-flexible assembly, a negative stiffness compression spring, a spherical hinge and an inhaul cable. The rigid-flexible assembly comprises a plurality of elastic plates and a plurality of rigid plates, a first groove is formed in the bottom of the rigid-flexible assembly, a spherical hinge and a plurality of negative-stiffness compression springs are arranged in the first groove, the upper end of the spherical hinge is fixedly connected with the groove bottom wall of the first groove, and the lower end of the spherical hinge extends into a second groove in the top of the first seat plate; the lower end of the spherical hinge is rotationally connected with the first base plate, and the multiple inhaul cables surround the rigid-flexible assembly. Dynamic and self-adaptive adjustment of lifting can be achieved, the normal shock insulation function of the structure is not affected while the whole structure is effectively prevented from being lifted, and the safety and stability of the structure under the action of extreme loads are improved.

The invention discloses a quasi-zero stiffness vibration isolator based on coupling of an inerter and a connecting rod and a parameter design method, and belongs to the technical field of vibration isolators. The quasi-zero stiffness vibration isolator comprises a connecting rod structure, a spring assembly, an inerter, a vibration isolation plate and a mounting base, the connecting rod structure comprises four connecting rods with the same length; the spring assembly comprises a connecting spring and two supporting springs; the rod pieces AB, AC, A 'B' and A 'C' are connected through hinge joints; two ends of AA'are connected with the inerter through connecting springs which are horizontally arranged in parallel; two ends of CC'are fixed on the mounting base, and two ends of BB 'are fixedly hinged on the vibration isolation plate; the BC end and the B 'C' end are connected through a vertical supporting spring; the supporting spring provides positive rigidity in the vertical direction, the connecting spring provides negative rigidity, and the inertial container amplifies the equivalent mass of the vibration isolation target through inertia so as to reduce the resonance frequency. The vibration isolator achieves low force transmissibility and displacement transmissibility under low-frequency excitation, and the adaptability and stability of the vibration isolator are enhanced.

The invention discloses a self-adaptive bearing weight quasi-zero stiffness vibration isolator and a control method thereof, and relates to the technical field of vibration isolation equipment. The device comprises a base, the tops of the two sides of the inner wall of the base are fixedly connected with horizontal guide rails, the horizontal guide rails are slidably connected with horizontal sliding blocks, the horizontal sliding blocks are fixedly provided with magnetic torsion negative stiffness mechanisms, the output ends of the magnetic torsion negative stiffness mechanisms are fixedly connected with connecting rods, and the other ends of the connecting rods are rotationally connected with a supporting table; the supporting table is located in the center of the base. The quasi-zero stiffness is formed by the negative stiffness of the magnetic torsion negative stiffness mechanism and the positive stiffness of the vertical spring so as to achieve low-frequency vibration isolation of equipment, quasi-zero stiffness matching of the vibration isolator to equipment with different weights can be achieved by adjusting the working length of the vertical spring, the optimal low-frequency vibration isolation effect is achieved, and the low-frequency vibration isolation efficiency is improved. And the non-linear stiffness of the quasi-zero stiffness vibration isolator for equipment with different weights is completely consistent, that is, the vibration isolator has the same dynamic characteristics under the equipment with different weights.

The invention provides a quasi-zero stiffness vibration isolation device and a track trajectory determination method and system, and relates to the technical field of precise supporting and vibration isolation. By adopting the horizontal telescopic guide rod, the linear spring and the nonlinear track, the sliding end of the telescopic guide rod is propped against the track to slide under the thrust of the linear spring. In the moving process of the mass block, the sliding track of the sliding end is a nonlinear similar parabola. The linear spring is pushed by the track due to the change of the parabola-like track during sliding, and the compression degree of the linear spring is changed, so that the magnitude of the acting force applied to the track by the sliding end is changed. The change of the track changes the direction of the counter-acting force of the track to the sliding end. Based on the synergistic effect of the horizontal telescopic guide rods, the linear springs and the quasi-parabola non-linear orbits, non-linear restoring force is generated through the non-linear shape of the orbits, quasi-zero-stiffness vibration isolation is achieved, negative-stiffness springs are prevented from being adopted, and the structure of the vibration isolation device is simplified in the mode that the orbits with the simple structure are adopted.

The invention provides an electromagnetic quasi-zero stiffness vibration isolation device and method based on a composite nested structure, and belongs to the technical field of vibration isolation. The device comprises a supporting base, two linear induction motor assemblies symmetrically arranged on the base and provided with a preset gap, and a suspension supporting frame composed of a vertical conductive supporting plate and a horizontal magnetic conductive supporting plate. The vertical conductive supporting plate can float up and down in the gap and forms a positive stiffness module for providing main supporting force and positive stiffness with the motor assembly, and the two eddy current stator pairs are symmetrically distributed on the left side and the right side of the horizontal magnetic conductive supporting plate and form a negative stiffness module for providing negative stiffness with the horizontal magnetic conductive supporting plate; each eddy current stator pair comprises an upper eddy current stator assembly and a lower eddy current stator assembly which are mutually exclusive up and down and float on the upper side and the lower side of the horizontal magnetic conductive supporting plate; the positive and negative stiffness modules are coaxially arranged and cooperate in parallel through a composite nested structure to realize the quasi-zero stiffness characteristic; the rigidity can be dynamically adjusted, and the vibration isolation effect and reliability are improved.

The zero-stiffness vibration isolator comprises a carrying platform and a coil base and further comprises a main supporting spring, an upper hollow shaft, a lower hollow shaft, a magnetic negative stiffness mechanism, a cam roller mechanism and a magnetic force controller, the main supporting spring is fixedly installed between the carrying platform and the coil base, the upper hollow shaft is coaxially installed at the bottom of the carrying platform through an M3 connecting screw, and the lower hollow shaft is coaxially installed at the bottom of the coil base through an M3 connecting screw. The lower hollow shaft is coaxially arranged on the lower portion of the lower hollow shaft, the magnetic negative stiffness mechanism is arranged at the bottom of the carrying platform, the cam roller mechanism is arranged on the coil base, and the magnetic force controller is installed on the coil base. The quasi-zero stiffness vibration isolator solves the problems that in the prior art, an existing quasi-zero stiffness vibration isolator is short in vibration isolation interval, small in vibration isolation mass, poor in vibration isolation effect and low in reliability.

This invention discloses a magnetorheological vibration isolator with negative stiffness characteristics, comprising a magnetorheological elastomer (MRE), an iron sheet, a circular magnet, a cylindrical central shaft, an electromagnetic coil, upper and lower base plates, an outer sleeve, and a bar magnet. The MRE, iron sheet, and circular magnet form a multi-layered MRE structure, with the circular magnet providing a portion of the initial magnetic field to the MRE. The electromagnetic coil, located between the multi-layered MRE structure and the outer sleeve, can control the magnetic field strength acting on the MRE in real time, thereby controlling the stiffness and damping of the MRE isolator. The bar magnet and magnet brackets form a negative stiffness generating unit, respectively installed on both symmetrical sides of the isolator. This invention introduces negative stiffness characteristics into a semi-active vibration isolator, improving the vibration reduction effect of semi-active control to the level of active control, while also offering good stability and low system cost. This invention can be applied to lateral vibration control in high-speed trains, improving stability and safety during high-speed operation, and has broad application prospects.

The embodiment of the utility model provides a shock absorber, a vibration isolation device, two device covers and refrigeration equipment, and belongs to the technical field of refrigeration, a first deformation mechanism has positive rigidity, and one end of the first deformation mechanism is installed on a main base. The adjusting blocks are connected with the other end of the first deformation mechanism, the adjusting blocks and the main base are arranged in the first direction, the adjusting blocks are arranged on the two opposite sides of the first deformation mechanism in a striding mode in the second direction, and the second direction and the first direction are arranged in a crossed mode. The auxiliary bases are arranged on the two opposite sides of the main base in the second direction. The second deformation mechanisms have negative stiffness, the auxiliary bases on each side are correspondingly provided with the second deformation mechanisms, and the second deformation mechanisms on each side are rotationally connected with the corresponding auxiliary bases and the corresponding ends of the adjusting blocks correspondingly. According to the shock absorber, the vibration isolation device, the two device covers and the refrigeration equipment, the good vibration isolation effect is achieved in a low-frequency interval, and vibration noise of the two device covers can be reduced.

The invention belongs to the technical field of quasi-zero stiffness vibration isolators, and particularly discloses a self-adaptive adjustment quasi-zero stiffness vibration isolator and a control method. Comprising a base and a bearing plate, and a plurality of positive stiffness units are arranged between the base and the bearing plate to provide basic support; the negative stiffness unit is arranged below the bearing plate, the two ends of the negative stiffness unit are connected with the adjusting structure through the moving unit capable of moving in the length direction of the driving unit, the adjusting structure is composed of a lead screw and an adjusting motor, the projection length of the negative stiffness unit in the horizontal direction can be changed, and therefore continuous adjustment of the negative stiffness is achieved. The vibration isolator is further provided with an acceleration sensor, a relative displacement sensor and a rotary encoder, and the sensors are connected with a processing unit to form a real-time monitoring and feedback control system. The low-frequency vibration isolation device can keep stable low-frequency vibration isolation performance under the condition change, and is suitable for high-precision equipment and complex industrial vibration environments.

The invention belongs to the technical field of vibration isolation, and particularly relates to a quasi-zero stiffness metamaterial sandwich structure, a vibration isolation device and a manufacturing method. The quasi-zero stiffness metamaterial sandwich structure is formed by periodically arranging unit cells in the horizontal direction, and each unit cell comprises an upper panel, a lower panel, a QZS resonator core body and a vertical supporting column; the QZS resonator core comprises a central mass block, QZS resonator units are arranged on the upper portion and the lower portion of the central mass block in a mirroring mode, each QZS resonator unit is composed of two quasi-zero-stiffness unit cells which are arranged in a crossed mode, and each quasi-zero-stiffness unit cell is composed of a negative-stiffness component comprising a horizontal curved beam and a positive-stiffness component comprising an oblique straight beam. According to the sandwich structure, the quasi-zero-stiffness resonator of a novel structure serves as a core body, wider application in the ultra-low frequency vibration reduction field can be achieved, the band gap is adjustable, and the problems that a traditional metal base material structure is high in band gap frequency and limited in application field can be solved.

The shock absorber with the negative stiffness characteristic comprises a cylinder barrel, a piston rod, a piston and a bottom valve, a stretching valve and a one-way valve are arranged on the piston, a compression valve and a one-way valve are arranged on the bottom valve, a valve element of the compression valve is connected to a valve element of the stretching valve through a spring, and a limiting device of the valve element of the stretching valve is arranged on the piston or the piston rod. Damping force values of the compression valve and the stretching valve are both controlled by the stroke of the piston and the acting force of the spring. In the stretching process of the shock absorber, when the spring is in a pressed state, the stretching valve forms damping force, and the shock absorption effect is achieved. The larger the compression stroke (compression force value) of the spring is, the larger the tensile damping value of the shock absorber is. In the compression process of the shock absorber, when the spring is in a pulled state, the compression valve forms damping force, and the shock absorption effect is achieved. The larger the stretching stroke (stretching force value) of the spring is, the larger the compression damping value of the shock absorber is.

Anti-vibration units are provided for vibration suppression in multiple directions. The anti-vibration units may have an X-shaped structure as part of its support structure. The anti-vibration units can work for ultra-low frequency vibration isolation in three directions in a passive manner. The anti-vibration units can achieve a flexible nonlinear stiffness, which contains zero or quasi-zero stiffness, negative stiffness and positive stiffness. A smooth multi-equilibria state is also achievable. Compared with traditional spring-mass-damper (SMD) and typical QZS systems, the provided anti-vibration units can have an enhanced QZS range of larger stroke with guaranteed loading capacity, and can also achieve a lower resonant frequency with a lower resonant peak. At least some embodiments of the anti-vibration units may include a new and innovative arrangement of components that enables a more compact design than typical anti-vibration systems.

The present application belongs to the field of ultra-precision vibration reduction, and discloses a precision active vibration reducer compatible with a vacuum environment, comprising: a top plate, a bottom plate, and a vibration reduction unit, wherein the vibration reduction unit comprises a passive vibration reduction unit and an active vibration reduction unit connected in parallel, the active vibration reduction unit being arranged between the top plate and the bottom plate and being located outside the air spring, and the passive vibration reduction unit comprising a coaxial and vertically arranged air spring and a magnetic negative stiffness spring; the air spring comprises a main air chamber, the bottom of the main air chamber being connected to a metal sealing bellows, the top of the main air chamber being flexibly connected to the top plate; the bottom end of the metal sealing bellows being sealed and fixed to the bottom plate, so that the main air chamber becomes a vacuum-sealed cavity; the magnetic negative stiffness spring being arranged in the air spring, and its top end being fixed to the upper wall of the cavity, and its bottom end being flexibly connected to the bottom plate. The present application has excellent vibration isolation performance and good adaptability to a vacuum environment, and can meet the vibration isolation requirements of equipment such as EUV lithography machines.

A kind of quasi-zero stiffness vibration isolation device based on negative stiffness generated by rotatable leaf spring, quasi-zero stiffness vibration isolation device includes positive stiffness component, negative stiffness component and height adjustment pad;Positive stiffness component, negative stiffness component and height adjustment pad are all installed in outer sleeve, and the bottom surface of positive stiffness component extends from the bottom of outer sleeve, beyond the bottom surface of outer sleeve, forms height difference on level;Negative stiffness component is located above positive stiffness component, and upper end surface extends the upper end surface of outer sleeve, outer sleeve is installed in floating plate, and moves up and down with floating plate together;The negative stiffness component is the negative stiffness component formed by rotatable leaf spring combination, and negative stiffness is generated by the change of rotatable leaf spring.The rotation or movement of rotatable leaf spring negative stiffness component in the process of vibration isolation forms matching negative stiffness, so that good quasi-zero stiffness low-frequency vibration isolation performance is obtained, and the vibration isolation efficiency of floating bed system is improved;It has the characteristics of simple structure, high reliability and long service life.

The invention relates to the technical field of building seismic isolation, in particular to a seismic isolation system with a vertical stepped quasi-zero stiffness characteristic and a design method of the seismic isolation system. A building three-dimensional seismic isolation system with the vertical stepped quasi-zero stiffness characteristic comprises a horizontal seismic isolation support arranged on the top face of a lower buttress; the positive stiffness system comprises at least one vertical steel spring, and the two ends of the vertical steel spring are connected to the top face of the horizontal shock insulation support and the bottom face of the upper buttress correspondingly. The negative stiffness system comprises a variable-slope guide plate, a horizontal multi-layer annular spring and a supporting plate, the thickness of the variable-slope guide plate changes in the height direction of the variable-slope guide plate, one end of the horizontal multi-layer annular spring abuts against the variable-slope guide plate, the horizontal multi-layer annular spring is connected to the supporting plate, and the supporting plate is connected to the upper buttress; the horizontal multi-layer annular spring can be driven to move along the surface of the variable-slope guide plate by changing the distance between the upper buttress and the lower buttress, and the horizontal multi-layer annular spring moves along the surface of the variable-slope guide plate, so that the length of the horizontal multi-layer annular spring is changed, and then negative stiffness is provided.

The invention discloses a low-frequency double-nonlinear quasi-zero-stiffness energy harvesting vibration isolator, and belongs to the technical field of nonlinear vibration control and energy harvesting. Comprising a supporting frame, an upper platform and a lower platform are horizontally installed on the supporting frame, and two vertical optical shafts are symmetrically installed and penetrate through the upper platform and the lower platform; the loading platform is used for bearing a vibration-isolated object and is mounted on the upper platform; the nonlinear negative stiffness structure is a bionic skeleton X-type mechanism arranged between the upper platform and the lower platform and provides negative stiffness restoring force; the non-linear positive stiffness structure is connected with the non-linear negative stiffness structure in parallel and provides restoring force which is non-linearly changed along with displacement; the energy harvesting unit comprises a copper film arranged on the inner side face of the supporting frame and a polytetrafluoroethylene film arranged on the outer side face of the upper platform, and the copper film and the polytetrafluoroethylene film form a friction nanometer generator. The problems that in the prior art, energy harvesting and ultralow-frequency vibration isolation energy harvesting cannot be carried out in a wider working frequency band are solved, and the vibration isolation energy harvesting efficiency can be effectively improved.

The invention relates to a piezoelectric type negative stiffness collaborative vibration absorption supporting rod for a helicopter rotor dynamic load. The piezoelectric type negative stiffness collaborative vibration absorption supporting rod comprises an upper supporting rod body, a lower supporting rod body and a vibration absorption assembly which is arranged between the upper supporting rod body and the lower supporting rod body and used for vibration isolation. The vibration absorption assembly comprises an auxiliary circular ring used for bearing a static load, a lever spring and a disc spring used for providing negative stiffness and adjustable pre-compression are arranged in the auxiliary circular ring, and a mass block used for absorbing and dissipating vibration energy is arranged below the disc spring; the two sides of the lever spring make contact with the piezoelectric ceramic stack, the piezoelectric ceramic stack is connected with the multi-mode external circuit module, the multi-mode piezoelectric shunt damping effect is formed, and meanwhile a plurality of mode components of the system are controlled. When vibration is large, electric energy is stored, and when vibration is small, the mode is switched to a multi-mode RLC circuit dissipation mode, and mechanical vibration energy is converted into electric energy which is consumed through the circuit. Negative stiffness dynamic low-frequency broadband vibration absorption and piezoelectric shunt multi-mode suppression are coupled, and the effect of efficient vibration isolation is achieved.

The invention discloses an electromagnetic permanent magnet hybrid quasi-zero stiffness energy feedback vibration isolator which comprises a bearing support, positive stiffness spring mechanisms, an electromagnetic negative stiffness mechanism and a pre-pressing spring mechanism, the multiple positive stiffness spring mechanisms are arranged on the outer ring in the bearing support, and the electromagnetic negative stiffness mechanism is arranged in the bearing support. According to the quasi-zero stiffness vibration isolator, the quasi-zero stiffness characteristic is achieved through parallel connection of negative stiffness permanent magnetic force and positive stiffness spring force, dynamic adjustment of the stiffness is achieved through electromagnetic force so that the vibration isolation system can reach the quasi-zero stiffness more accurately, and therefore the vibration isolation effect of the vibration isolator is improved. And meanwhile, an energy feedback coil is additionally arranged in the vibration isolator, and energy generated in the vibration process is converted into electric energy to be recycled, stored and utilized.

The invention relates to the technical field of structural engineering, in particular to a stable friction damper with segmented positive and negative stiffness characteristics and a modeling method of the friction damper. The friction damper comprises supports, and a pre-compression spring assembly, a lever assembly, a viscoelastic damper assembly and a rotating friction assembly which are arranged between the supports; the pre-compression spring assembly is used for achieving the negative stiffness effect, the lever assembly plays a role in increasing the force and the negative stiffness effect, and the pre-compression spring assembly and the lever assembly form a stable triangular deformation structure. The rotating friction assembly is used for providing friction damping force and guaranteeing the stability of the structure when the pre-compression spring assembly and the lever assembly rotate relatively. The viscoelastic damper assembly is used for applying vibration reduction control force to the structure when small-amplitude vibration of the structure is not enough to drive the friction surface to slide. The invention further provides a corresponding modeling analysis method, and the dynamic behaviors of the device in different working stages are accurately described.

The application discloses an eddy current negative stiffness magneto-rheological elastomer vibration isolator, which comprises an eddy current damping structure and a negative stiffness magneto-rheological elastomer structure, wherein the eddy current damping structure comprises a U-shaped permanent magnet and a conductor, and the U-shaped permanent magnet and the conductor are annular; the bottom of the U-shaped permanent magnet is mounted on a bottom plate; the top of the conductor is connected with a top plate, and the bottom of the conductor is mounted in the U-shaped permanent magnet to move in a cutting magnetic induction line mode; the bottom plate and the top plate are respectively mounted on a vibration source and a vibration-isolated structure; one end of the negative stiffness magneto-rheological elastomer structure is arranged in an annular inner ring of the U-shaped permanent magnet and connected with the bottom plate; and the other end of the negative stiffness magneto-rheological elastomer structure is arranged in an annular inner ring of the conductor and connected with the top plate. The application can reduce the amplitude of the vibration isolation system when passing through a resonance region, improve the relative vibration isolation effect, and prevent the vibration isolation system structure from being adversely affected due to resonance.

The utility model discloses a quasi-zero stiffness shock absorber for a camera, and belongs to the field of shock absorption. The quasi-zero stiffness shock absorber comprises a mounting seat, at least one group of disc spring shock absorption units are arranged on the mounting seat, a bottom cylinder is arranged below the mounting seat, a spring fixing column is arranged below the bottom cylinder, a spring is arranged on the spring fixing column, each disc spring shock absorption unit comprises a disc spring, one side, close to the mounting seat, of the disc spring is the inner side, and the other side of the disc spring is the outer side. A rubber inner ring and a metal inner ring are sequentially arranged on the inner side, a rubber outer ring and a metal outer ring are sequentially arranged on the outer side, the rubber inner ring is in contact with the disc spring, and the metal inner ring is in contact with the mounting seat. The positive stiffness structure and the negative stiffness structure are connected in series, so that the system has high static stiffness, low dynamic stiffness, large bearing capacity and low inherent frequency, and the purpose of broadband vibration isolation of the system is achieved.