677results about How to "Guaranteed symmetry" patented technology

A broadband coherent radar target simulator is composed of a receiving end, a transmitting end, a power divider, a lower mixer, an upper mixer, an instantaneous measurement receiver, a DSP processor, an interference modulator, a PC, a target echo delay compensation, a frequency modulation step frequency local oscillator and a high resolution radar signal simulation module. A shipborne radar transmits an X-wave band frequency modulation step frequency signal, a radar simulator receives the signal via a horn antenna, and the frequency modulation step frequency local oscillator generates a local oscillator signal; an intermediate frequency signal is generated after the dechirp processing of the lower mixer and is divided into two signals by the power divider, with one signal sent to the instantaneous measurement receiver to complete the measurements of radar carrier frequency signal, radar pulse repetition period, pulse width and pulse amplitude parameter, and with the other one sent to the high resolution radar signal simulation module to complete the simulation of a high resolution one dimensional object range image; the target echo delay compensation is used to solve the increase RMS attenuation problem of a dechirp time delay, and the compensated intermediate frequency signal is sent to the interference modulator. The broadband coherent radar target simulator of the invention is scientific in conception, less in use device number and low in cost.

The invention relates to a modular multi-level converter capacitor voltage fluctuation inhibition method under a low-frequency working condition, and belongs to the technical field of power electronics and motor drive. The method comprises the following steps: the alternating-current side three-phase phase current which meets the low-frequency working need is obtained by performing closed-loop control on the modular multi-level converter alternating-current side three-phase phase current; loop current only contains a direct-current component and a high-frequency alternating-current component by closed-loop control of the three-phase loop current, and a bridge arm voltage contains a high-frequency zero sequence component by overlapping high-frequency voltage at the midpoint electric potential at the direct-current side; the amplitude values, the frequencies and the phases of the loop current high-frequency alternating-current component and the bridge arm voltage high-frequency zero sequence component are obtained by operation, so that the phase voltage and the phase current of the alternating-current side do not contain high-frequency harmonic waves, moreover, the cycles of charging and discharging submodules are shortened, and the effect of inhibiting the capacitor voltage vibration of the submodules is realized; the electrical quantity of each bridge arm is kept to be balanced by the balancing control on the bridge arm energy so as to guarantee that the modular multi-level converter runs symmetrically and stably.

The invention provides a bionic double-joint flapping wing air vehicle and belongs to the field of aerospace. The bionic double-joint flapping wing air vehicle comprises a fuselage, a flapping wing driving device, a main wing, an aileron, a main wing joint, an aileron joint, an empennage driving device and an empennage. The bionic double-joint flapping wing air vehicle is characterized in that the fuselage comprises a fuselage transverse beam and two fuselage frameworks, wherein the two same fuselage frameworks are arrayed in parallel and are fixedly connected with the fuselage transverse beam; the fuselage transverse beam penetrates through the centers of the fuselage frameworks. The flapping wing driving device is fixedly connected with the fuselage frameworks; the main wing is connected with the fuselage frameworks by the main wing joint; the main wing can rotate relatively around the fuselage frameworks by taking the main wing joint as a rotary axis. The aileron is connected with the main wing by the aileron joint; the aileron can rotate relatively around the main wing by taking the main wing joint and the aileron joint as rotary axes. The empennage driving device 5 is fixedly arranged at the rear end of the fuselage transverse beam and the empennage is connected with the empennage driving device. According to the double-joint bionic flapping wing air vehicle, left and right flapping wing devices are fully symmetrical and the flight stability is improved.

The invention relates to a material micro-mechanical property biaxial tension-fatigue test system and a test method thereof, and belongs to the field of precise scientific instruments. The test method is characterized in that orthogonal tensile load is applied to a test piece to make two mutually vertical tensions exist in one plane, and fatigue load can also be applied to the test piece on the basis of the tensile load in order to research the micro-mechanical properties of a material under different load forms and load sizes. The system is composed of a precise loading-transmitting unit, a fatigue unit, a mechanics and deformation signal detection unit, and a test piece clamping unit. The test system has the advantages of novel and compact structure, respective realization of uniaxial tension test, biaxial tension test, uniaxial tension-fatigue test and biaxial tension-fatigue test, good compatibility with an optical microscope, and dynamic research of the relationship between the microstructure of the material and the deformation damage mechanism under tension-fatigue load conditions.

The present invention discloses an aspherical lens, including two refracting surface, in which at least one refracting surface is aspherical surface. Said invention also provides a formula for solve its form, and can obvisouly thin the lens, and make the field curvature superpose on the bend of far point spherical surface basically so as to make lens obtain excellent imaging quality.

The invention discloses a self-aligning bipolar transistor with an uplifted extrinsic base region or a heterojunction bipolar transistor and a fabrication method thereof, belonging to the technical field of semiconductor device fabrication. Firstly, a plurality of medium layers are deposited on a base; an emitter region window is formed through etching, then a medium inner wall is formed in the window; the medium layers (a plurality of) are selectively eroded on the basis of forming emitter region material through deposition or growing and etching, and then an uplifted extrinsic base region is formed through selective epitaxy method at the place vacated by the medium layers which are selectively eroded; and self-alignment of the uplifted extrinsic base region and the emitter region is realized due to the isolation action of the medium inner wall in the emitter region window, thus effectively reducing the base resistance of the device and thereby improving the speed, the frequency and the noise performance of the device.

The invention relates to a trimmer for a tea garden, and belongs to the technical field of agricultural machinery. The trimmer comprises a power assembly and a cutter assembly, wherein two eccentric wheels in the shell of the cutter assembly are in drive connection with two staggered shave-shaped blades respectively through connecting rods; the blades and a tool storage extending out of the shell form a moving pair; a left blade assembly and a right blade assembly are arranged, the upper ends of the left blade assembly and the right blade assembly are respectively articulated with one ends of a left trimming width adjusting rod and a right trimming width adjusting rod, and the middle parts of the left blade assembly and the right blade assembly are respectively articulated with one ends of a left dip angle adjusting rod and a right dip angle adjusting rod; the left trimming width adjusting rod and the right trimming width adjusting rod can be locked and articulated with the shell of the power assembly through chutes on the rod bodies; the left dip angle adjusting rod and the right dip angle adjusting rod are in variable locked connection; a power output shaft of the power assembly is in drive connection with a left power output spline shaft and a right power output spline shaft respectively through a left bevel gear pair and a right bevel gear pair; and the left power output spline shaft and the right power output spline shaft are respectively inserted in spline holes corresponding to the rotating centers of the eccentric wheels of the left cutter assembly and the right cutter assembly. The trimmer for the tea garden can be used for trimming two sides of shrub simultaneously, and also adjusting the trimming width and the trimming angles of two sides simultaneously.

The invention discloses a multi-parameter optical fiber grating sensor for temperature, wind pressure and wind speed measurement. The multi-parameter optical fiber grating sensor comprises an induced air pipe, an elastic sheet, an optical fiber grating A and an optical fiber grating B; a mounting hole is formed in the induced air pipe along the diameter direction, the elastic sheet is arranged in the mounting hole, and the center line of the elastic sheet and the diameter of the induced air pipe in the mounting hole are overlaid; the optical fiber grating A and the optical fiber grating B are symmetrically arranged in the center positions of two side faces of the elastic sheet, and are connected to optical fibers. As the optical fiber grating A and the optical fiber grating B are symmetrically arranged on two side faces of the elastic sheet, when wind is blown into the induced air pipe, one of the optical fiber grating A and the optical fiber grating B is subjected to tensile strain while the other is subjected to compressive strain, and the strain values are equal, so that errors are separated by means of a sum and difference relationship in a variation formula of wavelengths of the optical fiber gratings, and the measuring sensitivity is increased while the measuring error caused by a system is reduced.

The invention provides a six-traction device space debris net capture system which adopts level-1 launch and mass blocks synchronization launch and concentric circles rope net folding and receiving. The system comprises a launch subsystem which is composed of a launcher, a net hold, a cushioning device and a tether tension control device; a fly net subsystem which is composed of a rope net and mass blocks; the launcher is used for pushing the mass blocks at a predetermined distance from a target at a predetermined angle and to drive the rope net be pulled from the center of the net hold while unfolding to a fully unfolded state to capture the target after reaching the target location; the mass blocks are used for dragging the rope net so that the rope net is pulled out and unfolded and the net opening is tightened up to complete capture of the target; the number of the mass blocks is at least three and six mass blocks are adopted through optimized analysis; the tether tension control device is connected with the fly net subsystem and with the target through the rope net to pull the captured target off the track; the rope net is encapsulated in the net hold in a concentric circles package and is used to form sufficient coverage to completely surround the target.

The method involves detecting the tensile force acting on a twisted thread removed from a twisting spindle (2), and comparing the tensile force with a preset reference tensile force. The difference between the detected and reference tensile forces is determined as a correction factor of the driving force of a bobbin drive device (15). The driving force of the drive device and the shifting speed of a traversing device (9) are adjusted corresponding to each other, so that the windings of the twisted thread are arranged within a thread layer parallel to each other over a cross-wound bobbin (10). An independent claim is also included for a double wire twisting machine comprising a twisting spindle.

The invention provides a personalized garment customization plate making method, relates to the field of automatic plate making in the large-scale personalized garment customization process, and mainly solves the problem of rapid, accurate and automatic plate making under the condition of irregularly scanning a human body model. The method comprises the following steps: carrying out three-dimensional scanning of the human body and preprocessing of the mesh model; correcting the standing posture of the model; performing model regularization processing; extracting human body geometrical characteristics; performing standard meshing on the human body three-dimensional model; unfolding the basic clothes prototype; making a pattern garment cut piece plate; and carrying out online plate making server deployment. According to the method, rapid, accurate and automatic plate making of the garment customization model based on the three-dimensional human body scanning model can be achieved, manualintervention is not needed in the plate making process, and a technical solution is provided for large-scale personalized garment customization.

The invention belongs to a composite material molding technology, and relates to helicopter composite material paddle fatigue test piece molding technological process which is suitable for helicopter composite material technological process molding. According to the invention, a platform thickness spacing tool is adopted, an interval between two splints of a paddle fatigue test piece is effectively ensured, and simultaneously the positioning of the spacing tool can insure symmetry of the two splints; and a working procedure of numerical control processing is directly omitted from a technical process, furthermore a manufacturing cycle is also shortened, once alternating detection qualification rate of the paddle fatigue test piece is improved, the rejection rate of the paddle fatigue test piece is zero, and the stability and the smoothness of the assembly process of the paddle fatigue test piece are ensured.

This invention relates to a winded inner rotor of a double-port motor, in which, a hollow cylinder is installed on the rotor shaft, cavity cylinder is outside of the shaft and the hollow cylinder set in the double-layer hollow shaft, the inner shaft hole coaxial with the shaft is the inner layer hollow structure of the rotor shaft, the outer blind hole outside of the inner layer hollow structure is the outer hollow structure of the rotor shaft, radial through holes towards the surface of the rotor shaft are set close to the blind end of the blind hole and the inner shaft hole to connect to its inner radial cooling fluid path composed of the outer surface of the cylinder and the inner surface of the core and two end covers of the rotor, the outer surface of the hollow cylinder and the inner surface of the cavity cylinder constitute an axial path of the cooling fluid and the rotor winding is a central one.

The invention relates to a negative pressure adjusting device for an inlet of a compressor with a variable diameter, which is especially applicable to a compressor performance testing platform of a vehicular turbocharger, belonging to a machinery technical field. The negative pressure adjusting device comprises a fixing frame, a plurality of blades and an operation device; the blades are aligned according to the clockwise order, so that the peak end of every blade is pressed on the former one blade, blade rotating shafts are correspondingly inserted to blade rotating shaft positioning holes on the fixing frame one by one; so that all the blades are aligned in a fixing frame groove in a staggering manner. Stirring shafts on the operation disk are respectively crossed through the through grooves on the corresponding blades, and then the end parts of the stirring shafts are inserted to stirring shaft guide grooves of the fixing frame. With the adoption of the negative pressure adjusting device, the section of a through flow at the compressor inlet is conveniently and quickly changed, and therefore, the inlet negative pressure of the compressor is adjusted; the regular shape of the through flow face and the symmetry related to the pipeline center can be guaranteed, the air inlet resistance is reduced, and the bad influence on the test by the irregular shape of the air inlet is eliminated.

The invention discloses a norm constraint strong tracking cubature kalman filter method for satellite attitude estimation. The norm constraint strong tracking cubature kalman filter method comprises the following steps: 1, acquiring output data of a gyro and a star sensor; 2, determining state variables and measuration amount of a satellite attitude estimation system; 3, performing cubature kalman filter time updating and measuration updating at the moment of k to obtain one-step state prediction variance, one-step measuration prediction variance and cross covariance; 4, using a multiple gradual-fading factor for correction of the one-step prediction variance; 5, performing cubature kalman filter measuration updating again, acquiring state variance and state estimation variance at the moment of k +1; 6 if K + 1 = M (M is end moment of an attitude estimation nonlinear discrete system), outputting attitude quaternion and gyroscopic drift of state estimation of the moment of k +1 to complete the attitude estimation, if K + 1 < M, and k = K + 1, repeating steps 3, 4,and 5. The a norm constraint strong tracking cubature kalman filter method has the advantages of high estimation accuracy and strong robustness.

The invention provides a method for processing a shifting fork of automobile parts, which comprises the following steps: according to the requirements of a drawing, drilling a through hole and lathing the end face and downside surface of a convex plate; boring the through hole; raising a core rod and lathing the end face of the convex plate; milling the planes of two feet; milling openings; drilling, expanding and reaming two phi8<+0.045> holes on the outer circles of the machined hole; performing heat treatment through carbonitriding till the surface hardness reaches 59 to 63 HRC and the effective hardened depth reaches 0.1 to 0.3 millimeter; honing inner holes, wherein the position degree between the inner holes and the two phi8 holes is required to be less than phi0.1; testing with corresponding measuring tools and apparatuses; and deburring, washing, applying oil on, packaging and warehousing the shifting fork. The method fully guarantees the product in terms of symmetry, position degree, work hardness and high quality, greatly prolongs the service life of the product and meets the requirements for the rapid development of the automobile industry.

The invention provides a two-dimensional thermal-type wind speed and directions sensor based on ceramic packaging, and a manufacturing method therefor. The sensor comprises a ceramic substrate (1), an embedded silicon substrate (2), an insulating layer (3), a heating element (4), and four symmetric temperature measurement elements. The embedded silicon substrate (2) is embedded into the ceramic substrate (1), and the thickness of the part, above the embedded silicon substrate (2), of the ceramic substrate (1) is less than the whole thickness of ceramic. The embedded silicon substrate (2) is disposed in a cavity of the central ceramic substrate (1) in a central symmetry manner, and the lower surface of the embedded silicon substrate (2) is provided with the insulating layer (3). The lower surface of the insulating layer (3) is provided with the heating element (4) and four orthogonal temperature measurement elements. The sensor improves the sensitivity, and reduces the power consumption.

The invention provides an FM and PM signal carrier capturing method applicable to a random modulation degree. The method comprises following steps of firstly, carrying out down-sampling filtering to input digital baseband signals, thus obtaining down-sampled digital baseband signals; then respectively mixing the digital baseband signals with multiple groups of set local carriers, thus realizing frequency spectrum shift of the baseband signals; carrying out FFT conversion to each frequency spectrum shift branch signal; calculating the power of each spectrum line; searching spectrum line peak values region by region; storing searching results; after a plurality of times of searching is finished, carrying out frequency point verification; eliminating noise interferences, thus obtaining true signal spectrum lines; finally carrying out symmetry judgment to the obtained true signal spectrum lines, thus determining a capturing result. According to the method, the frequency resolution is improved through the frequency spectrum shift; the peak values are searched region by region in the whole capturing range according to the frequencies; the true signals are counted through many times of capturing; the weak signals can be searched in a low signal to noise ratio environment; and the method is applicable to FM and PM signal carrier capturing of random modulation degree.

The invention discloses a device and method for implementing zero theoretical locating errors of key slot dimensions in a shaft. The device comprises a base, a gear transmission mechanism and a shaft locating mechanism, wherein the gear transmission mechanism and the shaft locating mechanism are arranged on the base; the shaft locating mechanism comprises two slope locating pieces, a bottom surface locating piece and a hold-down mechanism; the two slope locating pieces symmetrically and inclinedly form a V slot; the bottom surface locating piece is positioned right below the V slot; the hold-down mechanism is positioned above the V slot; and the two slope locating pieces are connected with the gear transmission mechanism and are driven by the gear transmission mechanism to synchronously overturn. The V slot, which is formed by the two symmetrical slope locating pieces capable of synchronously overturning, the two sides and bottom surface of the fixed bottom surface locating piece locating shaft, and the top surface of the hold-down mechanism locating shaft are utilized to clamp the shaft to be processed. The method and device can simultaneously ensure the ideal precisions of zero dimension error in the key slot depth direction and zero position error of degree of symmetry in the key slot width direction.