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 provides a mutual correlation technology for measuring permeability stress sensitivity of ultra-low permeability rocks. The technology comprises the following steps: a) an ultra-low permeability rock core of shale or tight sand rock and the like is selected, and processed into a cylindrical sample; b) a cylindrical steel block standard sample is processed for system calibration; c) the measurement of ultra-low permeability is carried out through a periodic oscillation method, the pore medium can employ gas or water, and the measurement result of the steel block is used for calibrating the system; d) the rock core is placed in a clamp holder, and applied with confining pressure and pore pressure, the rock core is saturated, An upstream sine pressure wave is applied and kept constant, the responses of the downstream pressure waves at different confining pressures are measured; e) the downstream pressure waves at different confining pressures are subjected to mutual correlation analysis, the change of permeability with confining pressure is obtained. Combined with a periodic oscillation method for measurement of permeability of ultra-low permeability rocks, pressure waveforms for measurement of permeability are subjected to mutual correlation analysis, the precision of measurement of permeability change is raised, and the problem of measurement of ultra-low permeability stress sensitivity is solved.

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 provides a position signal damping method of an inertial navigation system based on variable damping coefficient. The method mainly comprises the steps of determining the introduction position of a signal damping network, treating the signal damping network and introducing a signal treatment network into the inertial navigation system. The method has the advantages and the characteristics that the introduction of parameters of a position damping network can realize the effective damping of periodic oscillation errors of the earth and greatly improve the precision of the system; although the introduction of the three-order position damping network increases the realization difficulty, the performances thereof are better than those of the first-order and the second-order damping networks; and the introduction of the position damping network with the variable damping coefficient can greatly improve the adaptability to the motion of ships and lead the method to be more applicable to a variety of motorized motion states of the ships.

The invention discloses a periodic oscillation laser welding method and a welding assembly. The method comprises the following steps that firstly, a to-be-welded workpiece is placed on a workbench, and a to-be-welded welding line is formed; and secondly, a welding laser is generated, the welding laser swings according to the preset pattern and the preset frequency, meanwhile, the workbench moves in the welding line track main direction, and the welding laser is used for welding the to-be-welded welding line. Light spots of the welding laser periodically swing with the small amplitude and at high speed according to the preset pattern, meanwhile, the workbench moves in the welding line direction, accordingly, a wide welding line and a curve welding line can be easily welded, the welding speed is high, and efficiency is high.

The invention provides a method for matching filter by gravity anomaly based on damping strapdown inertial navigation. The periodic oscillation property of a system can be damped by adding a gravity anomaly measurement module and adding a damping algorithm and a gravity anomaly value Kalman filter matching algorithm into a inertial navigation strapdown algorithm on the premise of not changing the precision of a system accelerometer and a gyroscope and not destroying the concealing property and independence of a strapdown inertial navigation system, the system error can be reduced, and the navigation precision of the system can be improved. According to the method, three periodic oscillation properties (including Schuler cycle oscillation, earth cycle oscillation and Foucault cycle oscillation) in the strapdown inertial navigation system can be eliminated by virtue of the damping property, so that the precision of the strapdown inertial navigation system can be improved to a certain extent. Navigation information acquired by the strapdown inertial navigation system can be corrected by the gravity anomaly value matching filter method.

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.

The invention discloses a digital linear voltage-stabilized power supply without finite periodic oscillation. The digital linear voltage-stabilized power supply includes a main loop, a threshold detection module, a logic control module, a shifting register, a PMOS array and a load, wherein the main loop is used for comparing output voltage with reference voltage and sending a comparation result into the logic control module; the threshold detection module is used for detecting whether or not the output voltage falls into a threshold window and sending a detection result into the logic controlmodule; when the output voltage exceeds top and bottom thresholds, the main loop controls the PMOS array to fast switch, and the output voltage is stabilized to the vicinity of the reference voltage;when the output voltage falls between the top threshold and the bottom threshold, the threshold detection module outputs a zone bit through the logic control module to make the shifting register entera hold mode, and circuit output is stable. The structure can eliminate the problem of finite periodic oscillation existing in a classical digital linear voltage-stabilized power supply. The inventionfurther discloses a digital linear voltage stabilizing method without finite periodic oscillation.

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.

A method for the transmission and damping of a mean torque with a superposed alternating torque having an input and an output. The mean and superposed alternating torque is transmitted along a torque path from the input to the output area. An input speed is a mean speed and a superposed alternating component. A slip arrangement is provided in the torque path between the input and the output for transmitting the mean and superposed alternating torque and generating a speed slip between an input speed and an output speed. The slip arrangement provides a maximum of an external activation of the speed slip in a area of the maxima of at least one periodic oscillation component of the alternating component and provides a minimum of an external activation of the speed slip in an area of the minima of at least one periodic oscillation component of the alternating component.

A method for the transmission and damping of a mean torque with a superposed alternating torque in an arrangement having an input and an output. The mean torque and superposed alternating torque are transmitted along a path from the input to the output. A slip arrangement is provided in the torque path between the input and the output for transmitting mean torque and superposed alternating torque and for generating a speed slip between an input speed and an output speed in the path. The slip arrangement provides a maximum of an external activation of the speed slip in the area of the maxima of at least one periodic oscillation component of the alternating component and provides a minimum of an external activation of the speed slip in the area of the minima of at least one periodic oscillation component of the alternating component.

A device for increasing the spectral bandwidth of optical pulses, comprises a hollow fiber waveguide (3A), optical components (5; 6) for focusing the beam (1) into the hollow fiber waveguide (3A) and for recollimating the beam at the exit of the hollow fiber waveguide, the hollow fiber waveguide (3A) being contained in an air-tight chamber (3B) filled with a gas at a given pressure; the length of the hollow fiber (3A) is such that, for a given input pulse energy and gas pressure, the energy contained in a fundamental propagation mode of the optical pulses that has minimum propagation losses exhibits substantially periodic oscillations over the full length (Lf) of the hollow fiber waveguide (3A) and reaches a local maximum at the output end (13) of the said hollow fiber waveguide.

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 discloses a control method of a bionic snake-shaped robot. A CPG mathematical model of the bionic snake-shaped robot is obtained through an electromechanical system in combination with simulation firstly. For the control over the joint gait of the robot and the mode switchover of the gaits, periodic oscillation signals generated by the CPG mathematical model are used for controlling the rhythmic movement of the robot. Iterative refinement is carried out on the unilateral and bilateral link weights in a CPG network through a genetic algorithm (GA). The feedback about the direction and speed of a motor is carried out in real time through a potentiometer, and obtained signals are used for carrying out feedback adjustment on output of feedback control and CPG control. Traditional dynamics computation and modeling are avoided, errors are reduced, multiple gaits and multiple phase relationships of the robot can be realized, and gait switchover can be directly realized in computer software. Instantaneity and controllability are improved, the bionic requirements are better met, and the multiple gaits and the function of smooth switchover among the gaits of the snake-shaped robot are realized.

The invention relates to a method for establishing an adjustable bifurcation point controller based on an integer order network congestion model, which comprises the following steps: analyzing the stability characteristics of an uncontrolled integer order network congestion model and a unique equilibrium point x*; applying a PD<1 / n> controller with adjustable bifurcation points to the uncontrolledinteger-order network congestion model, wherein at least the stability, Hopf bifurcation and periodic oscillation range of the researched system are satisfied; linearizing the network congestion model with fractional order controllerat the equilibrium point x*, and the characteristic equation of the linearized controlled system is obtained; selecting the time delay taoas the bifurcation parameter, and carrying out the stability analysis and bifurcation analysis through the characteristic equation of the controlled network after linearization in the aforementioned steps. By setting appropriatecontroller parameters, the occurrence time of Hopf bifurcation is effectively advanced or delayed, so that the congestion system becomes controllable and the ideal behavior is realized.

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.

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.

A toy snake that reproduces the natural movement of a snake as it moves across surface is described. The toy snake comprises a head that is pivotally mounted to a tail and a motor unit located within the head. In a preferred embodiment a body is employed to pivotally mount the head to the tail. The motor unit comprises at least two independently driven wheels located towards opposite sides of the head and the motor unit is configured to introduce a periodic oscillation between the operation of the independently driven wheels. The motor unit may also be configured to operate a tongue that extends out from the head to further increase the realistic nature of the toy. Embodiments of the snake may be adapted for use on land or water.

The invention discloses a laser active detection device based on a tunable liquid crystal variable refractive index, which relates to the technical field of photoelectric detection. The device comprises a laser, a collimating lens group, a tunable liquid crystal variable refractive index element, an extending lens group and a liquid crystal unit controller, wherein the collimating lens group is used for enabling light beams emitted by the laser to form collimating light; the self refractive index of the tunable liquid crystal variable refractive index element is changed to enable the collimating light focusing position to be changed in a reciprocating mode along an optical axis; the extending lens group is used for extending the collimating light; the liquid crystal unit controller controls the refractive index of the tunable liquid crystal variable refractive index element; and the laser, the collimating lens group, the tunable liquid crystal variable refractive index element and the extending lens group are arranged sequentially with the same optical axis. The periodic oscillation tuning of the focal power can be realized, the scanning frequency is high, fast and efficient scanning on the focal plane of a detected system in a target space domain can be realized, cat eye effect matching is realized, and the detection probability of the detected system is greatly improved.

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.

The invention provides a marine strapdown inertial navigation system horizontal-damping method based on an LMS (Least mean square) algorithm. The method is characterized in comprising the following steps that: S1: a marine strapdown inertial navigation system carries out real-time solving to collected a horizontal attitude angle and a course angle; S2: through a Schuler oscillation estimation algorithm based on the LMS algorithm, the Schuler oscillation component of the horizontal attitude angle is estimated; S3: the estimated Schuler oscillation component of the horizontal attitude angle is subjected to closed loop feedback to the marine strapdown inertial navigation system; and S4: marine strapdown inertial navigation system information is output in real time. By use of the method, the Schuler periodic oscillation component of the horizontal attitude angle is estimated by the LMS algorithm, then, the estimated result is used for carrying out feedback correction on the strapdown inertial navigation system, so that the horizontal damping of the inertial navigation system is realized, external information does not need to be imported, and therefore, the system has the advantages ofbeing small in calculated amount and good in damping effect.