71 results about "Periodic oscillations" patented technology

A simple, relatively inexpensive, non-contacting, full-field (total visible surface) measurement and visualization methodology is described to measure the object motions and the object stretches and object distortions (deformations) during oscillation of an object. The method is capable of full-field measurement of 1D, 2D and/or 3D object motions and the associated object surface deformations on vibrating objects. The methodology is based on a combination of stroboscopic image ascuisition and/or controlled image exposure time with a synchronization system to acquire the images at appropriate times during periodic oscillation of an object; the periodicity of the applied excitation is used to mitigate the requirement for high speed imaging. Then, image matching procedures, such as 3D digital image correlation, are used with software to extract full-field object motions and surface deformations at each time of interest.

A plasma source for generating nonlinear, wide-band, periodic, directed, elastic oscillations in a fluid medium. The plasma source includes a plasma emitter having two electrodes defining a gap, a delivery device for introducing a metal conductor into the gap, and a high voltage transformer for powering the plasma emitter. A system and method for stimulating wells, deposits, and boreholes through controlled periodic oscillations generated using the plasma source. The system includes the plasma source, a ground control unit, and a support cable. In the method, the plasma source is submerged in the fluid medium of a well, deposit, or borehole and is used to create a metallic plasma in the gap. The metallic plasma emits a pressure pulse and shockwaves, which are directed into the fluid medium. Nonlinear, wide-band, periodic and elastic oscillations are generated in the fluid medium, including resonant oscillations by passage of the shockwaves.

The invention relates to an arc oscillation-based gas shielded welding arc tracking method which comprises the following steps that after the welding is started, a welding gun starts doing a periodic oscillation along a direction vertical to a weld joint; a current sensor carries out real-time sampling on a welding current; sampled data is filtrated; filtered data is subjected to deviation judgment and converted into deviation data; and the deviation data is converted into a movement command, and a weld joint track is compensated in real time through a deviation rectifying device. Because sampled signals are filtered by adopting software, the arc oscillation-based gas shielded welding arc tracking method is high in response speed and tracking precision; and due to the adoption of a dual-filtering mode, the signal mutation caused by instable arc is reduced, the deviation compensation dosage is calculated by using known welding parameters, the support of a database or expert system is not needed, the requirement of a welding device on a weldment processing precision is lowered, and thus the arc oscillation-based gas shielded welding arc tracking method is an effective means for realizing the flexible automatic welding.

The invention provides a damping method of a fiber option gyroscope (FOG) strap-down inertial navigation system, mainly comprising the following steps: acquiring the initial attitude of a carrier by initial alignment; measuring angular velocity input and acceleration input on a carrier coordinate system; calculating an initial attitude matrix; converting carrier-system acceleration output into platform-system acceleration; acquiring all current velocity and angular velocity values; conducting horizontal damping on velocity information; calculating the attitude angular velocity of the carrier to a mathematics platform system; updating the current attitude matrix with quaternion numbers; outputting a carrier attitude angel; and entering the next time cycle. The invention adds suitable horizontal damping in a velocity information position of a horizontal loop of the system to eliminate the Shura periodic oscillation and the Foucault periodic oscillation of the system and adds a suitable directional damping network in an earth angular velocity input information position to eliminate the earth 24-hour periodic oscillation of the system, thereby improving the accuracy of a ship strap-down inertial navigation system.

The invention relates to the technical field of aerospace, and discloses an active control method and device for aerofoil drag reduction. A plurality of piezoelectric devices are uniformly arranged at the trailing edge of an aerofoil in advance, and when an aircraft takes off or flies at a low speed, the piezoelectric devices are controlled to dent so as to enable concave pits to be formed in the corresponding position of the aerofoil, so that the separation of the boundary layer is postponed and the pressure drag is reduced; when the aircraft flies at a high speed, the piezoelectric devices are controlled to be bulged so as to enable bumps to be formed in the corresponding position, so that the drag is reduced; or the piezoelectric devices are controlled to be in the periodic oscillation operating mode, so that the wake zone of the aerofoil is enabled to form a periodic vortex structure so as to control flow separation. The active control method and device for aerofoil drag reduction have the advantages that the aircraft is enabled to actively switch the corresponding drag reduction mode in different flight regimes, and the flight efficiency is improved.

A micromechanical motion sensor is capable of detecting a deflection imparted to an oscillatably mounted bar spring element excited to a permanent periodic oscillation by an electrostatic oscillating drive to which a periodic drive voltage is applied. To compensate non-linearities of the resonance frequency response of the bar spring element, a sum of a normal drive voltage signal and a compensation drive signal may be applied to a comb drive. In an alternative embodiment, separate compensation comb drive units may be additionally provided to the comb drive units used for the oscillation drive and a compensation voltage signal may be applied to them to compensate for the non-linearity.

Methods, systems, and devices for the location of oil and gas deposits are disclosed. The technology is based on the recording of natural (i.e. not man-made) oscillations of oil and gas environments under the influence of the energy of resonances of the gravitational tides. The recording is performed by low-frequency geophones (0.1-10 Hz). The resonances are recorded, graphed, and analyzed. The time of the onset of the resonances of 14-day gravitational tides is pre-calculated by adding the tidal waves from the Moon, the Sun, and the stress wave arising in the Earth's lithosphere in connection with the periodic oscillation of the position of the barycenter of the Earth-Moon system. The calculation of the time of the onset allows for the prediction of optimal times for surveying according to the method of the present invention.

The invention provides an inertial navigation system random error suppression technology by biaxial rotary modulation. Through selecting parameters such as a damping coefficient and an angular frequency parameter, an external horizontal damping network is designed, a rotation scheme for biaxial rotary modulation is designed, the best scheme is determined through comparing simulation results of different rotation breakoff schemes, the information measured and obtained by an inertial device is inputted to a biaxial rotary modulation system part, the navigation information with constant errors and slowing varying errors removed is obtained, and the navigation information obtained in the third step and external velocity information acquired by a Doppler log are inputted to an external horizontal damping network part, and a navigation result is solved. Biaxial rotary modulation and the external horizontal damping technology are adopted to achieve the damping effects and compensate the errors generated as Schuler adjustment conditions are damaged, the errors generated due to the acceleration and the speed can be compensated, 84.4 min of Schuler periodic oscillation and Foucault oscillation can be suppressed effectively, and the positioning, speed fixing and attitude determination precision of a fiber optic gyro inertial navigation system can be increased by more than 3 times.

The invention discloses a method for suppressing the rotational speed and torque ripple of a permanent magnet synchronous motor under a three-phase asymmetric fault. According to the characteristics of the rotational speed and torque periodic pulsation oscillation under the fault state, an iterative learning controller based on a rotor position is designed, a closed-loop iterative learning law with a forgetting factor is constructed, and the convergence analysis of the iterative learning controller is performed. By periodically compensating a cross-axis reference current iqref, the rotationalspeed and torque closely follow given values. The method of the invention is applied to the constant speed operation of the motor in the fault state and also has a good suppression effect on the periodic oscillation of the rotational speed and the torque during a shifting operation.

The invention discloses an operating circuit for a micro electronic mechanical system (MEMS) scanning micro-mirror spectrometer. The operating circuit mainly comprises three modules, namely an oscillation signal module, an MEMS micro-mirror drive control module and a spectroscopic data acquisition module, wherein the spectroscopic data acquisition module consists of a preamplification circuit, an analogue-to-digital (AD) conversion circuit, a first-in first-out (FIFO) storage, a field programmable gate array (FPGA) (or advanced RISC machine (ARM) and a singlechip) control circuit and a universal serial bus (USB) interface circuit. The MEMS micro-mirror drive control module performs closed-loop control over the MEMS scanning micro-mirror, so that the MEMS scanning micro-mirror vibrates at equal amplitude and equal frequency, the wavelength repeatability of the MEMS scanning micro-mirror spectrometer is improved; after periodic oscillation signals generated by the oscillation signal module are processed by the MEMS micromirror drive control module, periodic working signals are provided for the AD conversion circuit and the MEMS scanning micro-mirror at the same time, so that the AD conversion circuit and the MEMS scanning micro-mirror can work cooperatively; and therefore, periodic acquisition of spectroscopic data is realized. The operating circuit has the advantages that: the operating vibration of the MEMS scanning micro-mirror in the spectrometer is stable, the wavelength repeatability of the spectrometer is high, and the operating circuit is simple and is easy to realize.

An a system and method for chaos transfer between multiple detuned signals in a resonator mediated by chaotic mechanical oscillation induced stochastic resonance where at least one signal is strong and where at least one signal is weak and where the strong and weak signal follow the same route, from periodic oscillations to quasi-periodic and finally to chaotic oscillations, as the strong signal power is increased.

The invention relates to a relaxation oscillator which comprises a first amplifier and a second amplifier, wherein the first amplifier is provided with a first input end for receiving an output voltage signal, a second input end for receiving a reference voltage signal and an output end for comparing the output voltage signal with the reference voltage signal and responding comparison results to output a control signal; the second amplifier is provided with a first input end for receiving the output voltage signal, a second input end connected to the output end of the first amplifier to receive the control signal and an output end connected to the first input end of the first amplifier and the first input end of the second amplifier and used for comparing the control signal with the output voltage signal and responding comparison results to output the output voltage signal. The output voltage signal is a periodic oscillation signal with a non-sinusoidal waveform. According to the relaxation oscillator, the problem of clock pulse feed-in can be completely solved, the use area of a circuit board and the cost can be reduced, and noise in a circuit can be reduced.

The invention discloses a compensation method for non-linear periodic oscillation of a permanent magnet synchronous motor (PMSM) position signal. The compensation method includes the steps of acquiring the actual angular velocity and the actual angle of a rotor of the PMSM, obtaining an ideal angular velocity according to the actual angular velocity, obtaining the angular velocity difference through the ideal angular velocity and the actual angular velocity, obtaining the angle deviation according to the angular velocity difference, and using the angle deviation to compensate the actual angleof the rotor. According to the compensation method, compensation for the non-linear periodic oscillation of position signals is realized. The compensation method is simple, the operation is convenient, and the influence of the signal nonlinear periodic oscillation on the operation of the motor can be reduced to a certain extent. The actual engineering data shows that DC bias in the three-phase current can be effectively eliminated, the motor loss is reduced, and the operation stability of the motor is guaranteed.