93 results about "Resonance amplitude" patented technology

The invention relates to a method for on line identifying and dynamically inhibiting the resonance of an electromechanical servo system, relating to the field of electromechanical servo systems and aiming at solving the problems that the existing electromechanical servo system is poor in reliability caused by being damaged by mechanical resonance and wastes manpower and material resources in a maintaining process. The method comprises the steps of analyzing a signal spectrum output from a controller of the electromechanical servo system to obtain N spectrum values; comparing an obtained maximal amplitude value Hmax with a set threshold value Hth, inhibiting by adopting a notch filter method if the Hmax is more than the threshold value Hth and resonance frequency is 1.5 times higher than cross-over frequency till a resonance amplitude value is attenuated to be less than the threshold value Hth, and meanwhile, detecting the change of a phase angle at shearing frequency; if the resonance frequency is 1.5 times lower than the shearing frequency or the loss of the phase angle at the shearing frequency regulated by using a notch link is already more than 10 degrees, gradually transferring the shearing frequency forwards at the step size of h rad/s, and identifying a signal output from the controller of the electromechanical servo system again so as to inhibit the resonance. The method disclosed by the invention can be used for the electromechanical servo system.

The invention discloses a fiber reinforced composite material parameter identifying method based on laser nondestructive scanning, and a device. According to the fiber reinforced composite material parameter identifying method based on laser nondestructive scanning, the inherent frequencies, the damping ratio, and the resonance amplitude curves of the former three stages are input, and identification permissible error value is set to be 10%, so that fiber longitudinal elasticity modulus E1, fiber transverse elasticity modulus E2, shear modulus G12, Poisson's ratio v21, fiber longitudinal loss factor eta11, fiber transverse loss factor eta22, and shear loss factor eta12 are obtained.

The invention relates to a surface microstructure silicon cantilever enhancement type optical-thermal spectrum trace gas detection method and device. The device comprises a tunable laser, a reflective object, a surface microstructure silicon cantilever, a concave mirror, an optical fiber, an optical fiber coupler, a continuous laser, a laser controller, an optical detector, a signal processing system and the like. Modulated light emitted from the tunable laser is reflected on the concave mirror by the reflective object after passing through the gas to be detected, the received reflective light on the concave mirror is focused on a silicon surface of the cantilever beam. After the optical energy is absorbed by the cantilever beam, the optical-thermal deflection occurs to generate resonance. If the gas concentration is higher, the optical intensity absorbed by the gas is larger, and if the optical energy absorbed by the cantilever beam is smaller and the resonance amplitude is smaller. A length adjustable Fabry-Perot cavity is formed by an optical fiber end surface and a metal surface of the cantilever beam, the amplitude of the cantilever beam is demodulated to obtain gas absorption spectrum, furthermore the concentration of the detected trace gas is obtained. The device has the advantages of cheap price, small size, simple structure, convenience in use, strong flexibility, high detection sensitivity, and field work capacity and can be widely used in remotely detecting the components and concentration of a variety of or multi-component trace gas.

The invention discloses a process for machining a wearing ring of a cylinder liner of a large low-speed marine diesel engine. Radial clamping force which is applied by a clamping jaw for machining of a vertical lathe to the wearing ring is converted into axial clamping force applied to the wearing ring through a novel fixture to ensure that the action point of the clamping force is separated fromthe machining surface of a blank, and a workpiece is machined in a free state. Therefore, the phenomenon that the workpiece is deformed after the radial clamping force is applied to finish machining can be avoided. By repeatedly adjusting cutting parameters and process steps of a machine tool, the resonance amplitude is reduced so as to guarantee stable cutting and quality. The stress influence which is produced during turning can be eliminated in a mode of increasing processing frequency of a semi-finished product. Before finish machining and forming, stress deformation is eliminated throughone-time heat treatment, so slight deformation caused by machining can be eliminated, and inner stress of the workpiece can be released quickly and balance is achieved.

The present invention is a tuning fork oscillator for detection and measurement of corrosive or foreign materials. The elements include a means for mechanical excitation, and a mechanical oscillator, wherein said mechanical oscillator has a resonant frequency, f, and a quality factor, Q. A fuse fixed to the oscillator to change oscillator amplitude to or from essentially zero to resonance amplitude. In a preferred embodiment, the tuning fork has one region compatible with the service fluid and the other region is incompatible with the service fluid or other contaminant. The sensor alarms when a measured amount of the incompatible material has been removed or deposited.

A diaphragm is gained by the co-molded of a dome part, a voice coil junction part, a cone part and a peripheral part through the injection mold of thermoplastic resin. The thickness of the central part of the dome is made great so that the resonance amplitude in this part becomes small. In addition, an annular rib is integrally provided to the voice coil junction part so as to increase the junction strength between the diaphragm and the voice coil bobbin. Thus, the electromagnetic driving force of the voice coil can be effectively transmitted to the diaphragm so that a loud speaker with excellent characteristics can be gained.

The invention provides a control method and a control device for suppression of resonance of a grid-connected power generation system. The control method includes: detecting PCC voltage of a PCC point of the grid-connected power generation system in real time, processing the PCC voltage to acquire an effective resonance amplitude value thereof, comparing the effective resonance amplitude with a preset resonance threshold value, judging whether the grid-connected power generation system is in resonance or not according to a comparison result, if so, then determining a current correction according to the effective resonance amplitude value and the resonance threshold value, sending the current correction to each inverter to allow the inverter to adjust parameter according to the current correction until detecting that the effective resonance amplitude value of the PCC voltage of the PCC point is smaller than the resonance threshold value. Therefore, suppression of resonance of the grid-connected power generation system is achieved and stable and reliable running of the grid-connected power generation system and a power grid is guaranteed.

We describe RFID tags that incorporate a nonlinear resonator that self-adapts to the driving frequency of a reader. More particularly we describe an RF tag for sending data to a tag reader by modulating energy drawn from an RF field of said tag reader, the tag comprising: an antenna; a resonant circuit coupled to said antenna to resonate at a frequency of said RF field; a local power store to store power extracted from said RF field; a modulation system to modulate one or both of the resonance amplitude and a relative phase of a signal in said resonant circuit with respect to said RF field; and a feedback circuit coupled to said resonant circuit and to said local power store to control one or both of said resonance amplitude and said relative phase to control transients in said resonance amplitude caused by said modulation.

The invention discloses an enclosure structure and a pneumatic profile adjuster disposed on the outer surface of the enclosure structure. The pneumatic profile adjuster is of a grid-like structure capable of surrounding the enclosure structure, the grid-like structure includes multiple grid cells, bevel edges are arranged on the at least portion of the grid cells, and the angle of attack changes when fluid passes the bevel edges. The pneumatic profile adjuster changes the pneumatic profile of the fluid, so that the drag coefficient becomes smaller, the pressure difference between the enclosurestructure on the incident flow side and the back side is reduced, and therefore the forward resistance is reduced; and since the drag coefficient becomes smaller, the vortex-induced resonance amplitude in the lateral direction can be reduced, and the vibration is reduced.

The present invention is a mechanical oscillator for detection and measurement of corrosive or foreign materials. The elements include a means for mechanical excitation, and a mechanical oscillator, wherein said mechanical oscillator has a resonant frequency, f, and a quality factor, Q. A fuse fixed to the oscillator to change oscillator amplitude to or from essentially zero to resonance amplitude. In a preferred embodiment, the mechanical oscillator has the shape of a tuning fork where one region is compatible with the service fluid and the other region is incompatible with the service fluid or other contaminant. The sensor alarms when a measured amount of the incompatible material has been removed or the physical strength of the material has been compromised.

The invention provides an ultrasonic resonance spectrum detection method for a fatigue hardening layer of a roll, relates to the roll surface NDT (non-destructive testing) technology, and solves the problems that the conventional fatigue hardening layer of the roll cannot be detected quantitatively and the thickness requirement for the fatigue hardening layer to be tested is high. The ultrasonic resonance spectrum detection method comprises the steps that the roll surface is processed with uniform roughness; wideband ultrasonic signals are emitted to the fatigue hardening layer of the roll to cause resonance of the fatigue hardening layer, and the ultrasonic resonance circular frequency and the resonance amplitude are obtained; ultrasonic resonance spectrum signals in a certain band of the ultrasonic resonance frequency centroid; a signal spectral peak is detected from an ultrasonic resonance frequency position in the band, and is compared with a spectral peak of a standard test block provided with the fatigue hardening layer under the same detection conditions; the intensity of the spectral peak obtained through detection is subjected to quantization processing with an amplitude quantitative method; and a formant detection quantization distribution diagram for various positions of the whole roll body is formed through image visualization processing. The ultrasonic resonance spectrum detection method can be used for effective quantitative detection for various thicknesses of the fatigue hardening layer of the roll.

The invention discloses a vibration reduction block with conveniently regulated natural frequency and resonance amplitude and a front suspended crossbeam provided with the vibration reduction block. The vibration reduction block comprises a counter weight, a mounting base and a damping block made of elastic materials, wherein the damping block is installed between the counter weight and the mounting base, and the bottom of the mounting base is provided with a mounting bolt and a lock nut. The natural frequency of the front suspended crossbeam is the same as that of the vibration reduction block, and the natural frequency of the vibration reduction block is consistent with the resonance frequency of the front suspended crossbeam, such that a combination system consisting of the vibration reduction block and the front suspended crossbeam has two resonance frequencies which are respectively arranged on both sides of a resonance point of an original front suspended crossbeam when the vibration reduction block is not assembled, and the peak value of the combination system is smaller than the resonance peak value of the original front suspended crossbeam. Two new resonance frequencies and vibration amplitudes of the combination system can be adjusted by adjusting the mass and the natural frequency of the vibration reduction block, and the vibration frequency of an engine is avoided as far as possible, thus the purpose of reducing noise is realized.

The invention relates to a monitoring method for LPFG (Long Period Fiber Grating) transverse load direction characteristic based on resonance amplitude modulation and an asphalt pavement pressure sensor, belonging to the field of optical sensing testing. The method comprises the following steps of: (1) demarcating a linear area of long cycle fiber Bragg grating resonance peak amplitude and transverse load relation curve; (2) during the transverse load monitoring, selecting the linear sections of all external loading varying ranges falling in the liner area, selecting the angle corresponding to the linear section of the highest sensitivity in the linear section according with the condition as a thrust surface; (3) using the characteristics of the long cycle fiber Bragg grating resonance peak amplitude and the transverse load relation to process pressure monitoring. The method is high in sensitivity and is not easy to be disturbed.

The invention relates to oscillating type dampers used for vibration prevention of a tower. Each oscillating type damper is composed of a connection rod, a spherical hinge, an oscillating bar, a mass block and a spring, wherein one end of the connection rod is connected with a tower body, and the other end of the connection rod is in threaded connection with the spherical hinge; the oscillating bar is perpendicular to the connection rod, one end of the oscillating bar is connected with the spherical hinge in a welded mode, and the mass block is welded to the other end of the oscillating bar; the spring is parallel to the connection rod, one end of the spring and the mass block are connected in a welded mode, and the other end of the spring and the tower body are connected in a welded mode. The dampers are arranged symmetrically. Vibration prevention measures are taken when resonance of the tower occurs. The amplitude of vibration of the tower body is reduced rapidly by increasing damping of the tower body, the resonance amplitude of a tower top is reduced, and accordingly damage to the tower from resonance is reduced.

The invention relates to a fiber grating resonant biosensor, which belongs to the technical field of fiber optic sensors. It includes LD light source, fiber directional coupler, Labview monitoring platform, fiber grating demodulator, matching liquid, biosensing probe, biomolecular film, trapezoidal metal coating, F‑P resonant cavity, and microprocessed fiber grating. The present invention affects the quality factor of the fiber Bragg grating bioresonance sensor through the reaction of the biomolecular film with the substance to be measured, and then affects the resonance amplitude of the fiber Bragg grating tapered cantilever beam, and finally changes the reflection center wavelength of the fiber Bragg grating resonance biosensor, through F-P resonance The cavity matches the reflected signal and compensates the temperature to improve the detection accuracy. The invention has simple structure, satisfies the requirement of miniaturization of biological detection, and can realize real-time detection.

The invention discloses a sound-absorbing large-damping self-resetting track mechanism, which adopts a C-shaped track body. The track body is injected with a two-color injection mold. The inside of the track body is inlaid with rubber materials. Dry friction occurs between the rail bodies. The bullet bears the extrusion force of the gear slot, and the internal spring is compressed accordingly. The extruded spring has the function of storing energy. When the external force is removed, the spring returns to its original state, and the whole mechanism is reset at the same time. The present invention adopts a structure with large damping to help reduce the resonance amplitude of the structure, and avoid mechanism damage caused by the vibration stress inside the structure; it helps the mechanism to quickly recover to a stable state after being subjected to an instantaneous impact; Acoustic radiation from mechanical vibrations. The present invention also realizes the shift form of the internal mechanism of the gear shifter, which is self-resetting. This mechanism is realized by the principle that the spring deforms under the action of the external force and returns to its original shape after the external force is removed.

A kitchen ventilator shell with a noise interference device is provided with a shell body and the noise interference device for reducing multi-frequency noise. The noise interference device is assembled to the shell body. Specific multi-frequency noise lowering is achieved by adjusting the area of two openings of the noise interference device, the integral length of the noise interference device or the shortest distance between the two openings. A long-term good noise lowering effect can be kept for the kitchen ventilator shell, and the noise interference device has the advantages that cost islow and reliability is high. The noise interference device interferes with noise transmitted in a main air flue pipe through the resonance amplitude and phase position of the specific noise frequency, accordingly, the amplitude of the noise frequency is reduced, and noise lowering of the specific multi-frequency noise is achieved. The material of the noise interference device is resistant to corrosion and chemical corrosion and is not prone to damage. The long-term good noise lowering effect can be kept for a kitchen ventilator, and the noise interference device has the advantages that cost is low and reliability is high.

The invention relates to the fields of the generalized resonance demodulation technique and the optical fiber sensing technoology, provides a fiber-bragg-grating-based resonant train bearing damage detection sensor so that a problem that key parameters like the real-time temperature, vibration frequency, and accelerated speed of the train bearing need to be analyzed in the early warning online monitoring application for train bearing damages can be solved. On the basis of impact excitation generated by early-stage damages of a bearing structure, a mechanical structure formed by a mass block, acompliant body and a bolt generate resonance, the peak wavelength of a solidified fiber sensing unit in the compliant body is in direct proportion to a system resonance amplitude, a maximum amplitudevalue is reached at a resonance frequency, so that resonance amplification detection is realized for a micro impact signal. Besides, a bearing temperature sensor is integrated into the sensor; and early-stage early warning monitoring of the damage of a train bearing is realized by fusion analysis of the temperature, vibration and impact resonance information. The sensor is suitable for online early warning monitoring of damages of various bearing type mechanical structures.