83results about How to "Suppression offset" patented technology

The invention relates to a direct-current electric field sensing system with a rotating structure, which realizes accurate measurement of a direct-current electric field. The system comprises a laser, a rotating structure and a detector, the rotating structure comprises a single-mode fiber slip ring, a collimating mirror, a polarizing film, a 1 / 4 wave plate, a crystal and a multimode fiber slip ring. Experimental results show that the scheme has the advantages of high response speed and strong anti-electromagnetic interference capability, and the aims of inhibiting light beam offset, realizing light beam collimation and achieving high-precision measurement can be fulfilled by utilizing the rotating structure and the optical fiber slip ring.

The invention discloses an ultra-wideband low-profile feed source loaded with a step medium, and relates to the field of ultra-wideband feed sources. The antenna comprises four log-periodic antennas, four groups of step dielectrics, dielectric cylinders, a reflection floor, a metal cavity and two feed baluns, the four log-periodic antennas are divided into two pairs which are orthogonally arranged, each pair comprises two log-periodic antennas which are oppositely arranged, the log-periodic antennas are fixed on the dielectric cylinder through screws, and an included angle is formed between the log-periodic antennas and the reflection floor; each group of stepped dielectric is formed by arranging twelve dielectric blocks in height stepped distribution, is positioned between the log-periodic antenna and the reflection floor, and clings to the reflection floor; the two feed baluns are orthogonally arranged, and each balun comprises a dielectric substrate, an index gradient microstrip line and a one-to-two power divider. The antenna is wide in frequency band, low in profile and suitable for serving as a primary radiator of a reflector antenna in the fields of satellite communication, radar detection, radio astronomy and the like.

This invention discloses a large-tapered anti-backlash tailstock adapted to a four-axis rotary table, specifically relating to the field of tailstock technology. It includes a base with a positioning and locking assembly. The positioning and locking assembly includes a central inner liner plate located in the middle of the base, with a mounting cavity in the center of the inner liner plate. An axially adjustable crossbar is inserted into the mounting cavity. This invention employs a dual-redundant structure of hydraulic and mechanical locking to fundamentally prevent the tailstock from backing up under force. The locking force is uniform and sufficiently rigid, achieving zero axial displacement positioning of the tailstock rod, thus laying a solid foundation for machining accuracy. Simultaneously, the dual locking, combined with a two-stage adjustment mechanism of coarse and fine axial adjustment, allows for deep synergy between adjustment and locking functions. Once adjusted to the correct position, the tailstock is quickly locked, improving positioning accuracy and making the anti-backlash effect more stable.

The mold comprises a main body base, the main body base is divided into a placement seat and a lower base, a supporting seat is arranged between the lower base and the placement seat, the inner end of the placement seat is of a cavity structure, and a threaded hole used for fixing a workpiece is formed in the horizontal plane of the upper end of a cylinder of the placement seat; a square blind hole facilitating fastening of a workpiece is formed in the upper side of the outer cylindrical surface of the placement seat, a strip-shaped hole is formed in the lower end of the outer cylindrical surface of the placement seat, and the square blind hole corresponds to a threaded hole for fixing the workpiece. The problems that in traditional machining, positioning is not accurate, stability is poor, and cleaning and maintaining are difficult are solved, the efficiency and precision of the machining process are remarkably improved, the adopted cavity structure is perfectly attached to a workpiece, the design of a threaded hole and a pin hole for precise positioning is matched, and the machining precision is greatly improved. And the absolute positioning accuracy and the posture stability of the gyroscope outer shell assembly in the machining process are ensured.

The invention discloses a live broadcast picture stabilizing method based on artificial intelligence, relates to the technical field of artificial intelligence, and can further improve the picture stability through picture stability evaluation and filter dynamic adjustment. The stability degree of the current picture is evaluated by calculating a picture stability index Sx (t), and when an output result is lower than 0.7, a filter dynamic adjustment mechanism is triggered. And executing a dynamic adjustment mechanism of the filter by adjusting the size Nnew of the window, and further smoothing the image jitter. After the step S1 and the step S2 are executed twice, the jitter amplitude delta P (t) is compared with the jitter threshold Pthreshold, an early warning mechanism is triggered to remind a photographer to adjust the posture of the equipment, and abnormal image jitter caused by the fact that the motion of the equipment exceeds the limit is avoided in time. According to the feedback process of stability evaluation and filtering optimization, the adaptability and stability are remarkably improved, and it is ensured that the live broadcast picture quality is kept stable and smooth in a high-dynamic motion scene.

The utility model relates to a kind of buckle wire fork assemblies of double-needle computerized embroidery machine.It involves embroidery machine technical field.The application specifically includes the buckle wire mounting plate fixedly connected with shuttle box body, the buckle wire driving mechanism fixedly connected with buckle wire mounting plate, the buckle wire guide mechanism fixedly connected with buckle wire mounting plate, and buckle wire mechanism;The upper fulcrum of buckle wire mechanism bottom is connected with buckle wire driving mechanism, the lower fulcrum of buckle wire mechanism bottom is connected with buckle wire guide mechanism, buckle wire driving mechanism is used to drive buckle wire mechanism swing around lower fulcrum, and buckle wire guide mechanism limits the swing of buckle wire mechanism around lower fulcrum.Two buckle wire forks symmetrically provided on the buckle wire mechanism of the utility model, when buckle wire driving mechanism drives buckle wire mechanism swing around lower fulcrum, buckle wire mechanism can simultaneously carry out the buckle wire and loose line of double-needle surface thread through two buckle wire forks symmetrically arranged, to reduce the occupation of space by buckle wire fork assembly, and then make the structure of double-needle computerized embroidery machine more compact.

The coil assembly device includes a blade, which is inserted into the slot of the stator core when the insulating paper is inserted into the slot. In the coil assembly method, the insulating paper is inserted into the slot of the stator core, the blade is inserted into the slot into which the insulating paper has been inserted, and the coil is inserted into the slot into which the blade is inserted in a direction opposite to the direction in which the blade is inserted. When the coil is inserted into the slot, the blade is pulled out of the slot along with the insertion of the coil into the slot.

The present invention discloses a midpoint potential control method of an NPC four-bridge arm inverter with low switching frequency, comprising the following steps: S1, obtaining a three-phase reference voltage, comparing the three-phase reference voltage with a neutral bridge arm reference voltage, and obtaining the maximum and minimum values ​​of the four reference voltages; S2, establishing two positron modulation waves of each bridge arm, deriving a general expression of the two positron modulation waves of each bridge arm, and calculating the optimal bias voltage and the two optimal positron modulation waves of each bridge arm; S3, calculating the modulation wave adjustment value of the midpoint current adjustable bridge arm; S4, obtaining the adjusted two positron modulation waves of each bridge arm according to the two optimal positron modulation waves of each bridge arm and the modulation wave adjustment value; S5, comparing with a single carrier to generate a pulse signal for controlling the on and off of a power switch tube. The present invention adopts the above-mentioned midpoint potential control method, and has a lower switching frequency and similar midpoint potential low-frequency oscillation control capability.

The application discloses a mirror glass substrate positioning cutting table and belongs to the technical field of glass positioning and cutting. In order to solve the problem that slight warping deformation is easily generated in the production and transfer process of the mirror glass substrate, the warping is not easy to detect and level, and the processing quality of the mirror glass substrate is affected, the application comprises a workbench, a moving assembly is arranged on the top of the workbench, a laser cutting head is installed on one side of the moving assembly, a positioning assembly is arranged in the workbench, a lifting assembly is arranged in the workbench, a plurality of offset compensation assemblies for self-adapting center offset and eliminating the pull-down coaxiality error are uniformly arranged in the lifting assembly, the mirror glass substrate warping can be followed to realize the conformal attachment of the suction cup, the deflection inclination data at all places are collected in real time, the out-of-gauge working condition of the substrate warping is automatically recognized and early warning screening is carried out, the unqualified workpieces are avoided to be machined, and the glass cutting waste rate is effectively reduced.

This invention provides a multi-energy field assisted ultrasonic cutting device and method for CFRP preforms, relating to the fields of intelligent manufacturing and precision machining technology. The invention uses a laser generator to precisely and locally heat the cutting area, softening the resin matrix in the processing area and significantly reducing the material's strength and cutting resistance. Simultaneously, eddy current tubes cool the non-cutting areas of the workpiece, enhancing the stiffness of the resin matrix in these areas and the constraint force on the carbon fibers, effectively suppressing excessive deformation and displacement of the carbon fibers during processing. Ultrasonic vibration further induces brittle fracture of the carbon fibers through high-frequency impact, reducing the tensile effect caused by resin viscosity. Ultimately, this achieves the beneficial effects of high-quality, high-efficiency, and low-damage processing of CFRP preforms.

The utility model relates to the field of hoist accessory, concretely relates to a hoist tail rope anti -twisting device, including fixed frame and two groups of constraint frame, two groups of constraint frame are respectively rotationally arranged in fixed frame both sides, the opposite side middle part of two groups of constraint frame all are fixed with limit stop, two limit stops opposite sides can mutually adhere, two groups of constraint frame opposite sides both sides all are provided with inner branch and outer branch, and the inner branch and the outer branch of adjacent position are located constraint frame same side, and the inner branch is located in the inner side of outer branch and can mutually abut tightly, and adjacent inner branch and outer branch constitute the blocking structure, the utility model discloses when one side tail rope occurs torsion and extrudes this side inner branch, not only does this inner branch limit the constraint of tail rope, still through the abutment cooperation with the outer branch of same side, the tail rope pressure of self -sustaining is conducted to the constraint frame of another side, thereby when tail rope deflection is by both sides constraint frame synchronous provides the constraint force of constraint, and the tail rope pressure is borne in common, effectively suppresses the deflection of tail rope.

The application discloses a high-rigidity linear sliding rail with automatic centering and four-direction load capacity, and particularly relates to the technical field of linear sliding rails, and comprises a guide rail, a sliding block is slidably arranged on the top of the guide rail, and a transmission unit is arranged on the inner side top end of the sliding block and comprises two groups of upper load bearings arranged in a symmetrical mode. The four-column circular-arc ball groove and the 45-degree contact angle of the steel ball can balance the four-direction load of the radial direction, the reverse radial direction and the horizontal and vertical directions, and realize automatic centering. Four groups of pre-pressing clamping positioning blocks are arranged between the sliding block and the bottom end of the guide rail, so that the installation precision and the operation stability of the sliding block on the guide rail can be obviously improved, the deviation and vibration in the sliding process can be further inhibited, the accurate positioning and the guiding constraint for the linear motion can be continuously provided, the high-precision smooth sliding of the sliding block along the guide rail axis direction is realized, and the positioning precision and the motion smoothness in the linear transmission process are double-protected.

This utility model relates to an online outer diameter measuring device, including a detection mounting base and an outer diameter measuring pen. Two material support frames are fixedly mounted on the detection mounting base, arranged along the length of the base, and each frame has a bearing groove adapted to the workpiece shape. A first guide rail is fixed on the detection mounting base between the two material support frames, and a second guide rail is slidably mounted on the first guide rail via a first slider. This utility model utilizes the V-shaped bearing grooves on the material support frames to adapt to the workpiece shape, combined with an anti-slip and wear-resistant pad adhered to the groove walls. Through the V-shaped positioning principle, the workpiece is stably supported. The anti-slip and wear-resistant pad increases the friction between the workpiece and the pad, effectively suppressing workpiece offset or tilting caused by placement deviation or rolling, ensuring that the workpiece axis remains consistent with the detection reference, and fundamentally reducing errors caused by detection position deviation.

The application discloses a stable control method for power regulation of a two-stage series-connected impulse power station with a regulating pool, which firstly establishes a mathematical model of the series-connected impulse power station with the regulating pool, and proposes a power-water level coordinated control strategy, namely, a proportional integral control strategy with a relative value of a power deviation of a first-stage power station as an input signal for the first-stage power station, and a double proportional integral control strategy with a relative value of a power deviation of a second-stage power station and a relative value of a water level deviation of the regulating pool as input signals for the second-stage power station; on the basis, a stability analysis model of the series-connected power station is constructed, and a determination method for the governor control parameters of the first-stage power station and the second-stage power station is proposed. The control method proposed by the application not only can realize the rapid and stable regulation of the power of the series-connected power station, but also can effectively guarantee the fluctuation stability of the water level of the regulating pool, has the advantages of clear physical meaning and strong engineering applicability, provides a theoretical basis for guaranteeing the synchronous stable operation of the series-connected impulse power station with the regulating pool, and has a wide application prospect.

The invention discloses a writing method of a ferroelectric field effect transistor array, and belongs to the technical field of micro-nano electronics. According to the method, a self-compensation write-in method is provided for a multi-stage storage ferroelectric field effect transistor array of a 1T structure, a pulse sequence of a self-compensation waveform is adopted for write-in and corresponds to different storage states in multi-stage storage, positive pulse write-in is adopted when the pulse sequence is higher than an intermediate storage state, and negative pulse write-in is adopted when the pulse sequence is lower than the intermediate storage state. The method comprises the following steps of: writing a FeFET memory cell, performing read verification on a written state of the FeFET memory cell, starting an error correction program for correction when a write error is found so as to reach a target state, and starting a durability recovery program to recover the performance of the FeFET memory device if the error correction program fails; the method simultaneously solves the reliability problems of large fluctuation between devices and between cycles, limited durability and serious write-in crosstalk, has the advantages of simple process, low hardware overhead and the like, is compatible with the current advanced node CMOS technology, and is easy to implement.

The utility model relates to the field of thread detection, and discloses a multi-specification thread detection go-no go gauge device, comprising a detection bench, the top of the detection bench is provided with a switching mechanism and a limiting guide mechanism, the switching mechanism comprises a lifting plate, the bottom of the lifting plate is fixedly connected with a circular block, the inner wall of the circular block is rotatably connected with a cross-shaped rotating block, and the cross-shaped rotating block is fixedly connected with the detection bench. A limiting lifting block is slidably connected to the inner wall of the cross rotating block, a connecting rotating cylinder is rotatably connected to the inner wall of the limiting lifting block, and a supporting rotating plate is rotatably connected to the inner wall of the circular block. According to the utility model, through the arrangement of the switching mechanism, a plurality of go / no-go gauge detection heads with different specifications can be loaded at the same time, when different thread specifications need to be detected, the motor II drives the cross-shaped rotating block to rotate, the detection heads with corresponding specifications are rapidly switched, manual tool replacement is not needed, automatic control of detection head switching is realized, manual operation links are reduced, and the detection efficiency is improved. The labor intensity is reduced, and the detection efficiency is greatly improved.

The utility model relates to a locating frock relates to frock clamp technical field, the locating frock includes base, locating table and locating piece, locating table is fixed on the base, and locating table is detachably connected with locating plate, the locating plate is provided with abdicating hole for the drill bit to pass through, and one side bottom wall can abut against the end portion of work piece, locating piece is located on the locating piece, locating piece is located on the locating piece, locating piece is located on the locating piece. The positioning block is arranged on the base and can slide towards the positioning table, and a buffering piece which can abut against the handle part of the workpiece is arranged on one side of the positioning table. Through the combination of the positioning plate, the buffer piece and the positioning block, the workpiece is wrapped to be positioned, the good limiting effect is achieved, and the effect of preventing the workpiece from deviating in the drilling process is achieved.

The invention relates to the technical field of diving equipment manufacturing, and particularly discloses a Beidou antenna integrated underground water monitoring equipment protection device which comprises an equipment body, a protection assembly used for protecting the equipment body, a scraping assembly used for cleaning the protection assembly and a detection assembly used for detecting whether floating garbage exists on the protection assembly or not. The equipment body is covered with a shell, the protection assembly comprises an anti-collision plate and an elastic telescopic rod, and the anti-collision plate is rotationally arranged on the shell through the elastic telescopic rod; the detection assembly comprises a rotating shaft, a turbofan and a rotating speed sensor, the rotating shaft and the turbofan are installed on the anti-collision plate, the rotating speed sensor is installed on the rotating shaft, and when floating garbage is intercepted by the anti-collision plate, the rotating speed of the turbofan can be decreased, so that detection of the floating garbage on the anti-collision plate is achieved, and then cleaning treatment can be conducted through the scraping and cutting assembly. The underground water monitoring equipment has the effect of improving the impact resistance, the self-cleaning capability and the monitoring reliability of the underground water monitoring equipment.

A stator iron core, an insulation sleeve, a motor stator, a motor, a power assembly and a vehicle are provided, the stator iron core is provided with an installation groove extending along an axial direction, the installation groove is suitable for accommodating a winding, the groove wall of the installation groove is convexly provided with a plurality of limiting projections, the plurality of limiting projections are suitable for abutting against the winding, and the insulation sleeve is arranged on the insulation sleeve. The at least two limiting protrusions are symmetrically arranged on the groove walls of the two sides of the mounting groove. In the application, the groove wall of the mounting groove is convexly provided with the plurality of limiting bulges at intervals, the winding is connected with the plurality of limiting bulges, and the at least two limiting bulges are symmetrically arranged on the groove walls at the two sides of the mounting groove, so that the two sides of the winding are uniformly stressed, and the winding is prevented from deviating or inclining relative to the stator core due to overlarge stress at one side; and the positioning effect on the winding is improved.

A diaper according to one embodiment of the present invention is provided with: an absorbent main body comprising a surface sheet disposed on the skin surface side of a wearer, a back sheet disposed on the non-skin surface side on the opposite side from the skin surface side, and an absorbent core disposed between the surface sheet and the back sheet; and a pair of fastening pieces extending from the absorbent body to the outside in the lateral direction. A guide mark for guiding a position at which the buttocks of the wearer should be arranged is formed on the absorbent body so as to be visible from the skin surface side, and the absorbent core is at least partially narrowed inward in the lateral direction at a position closer to the belly side than the guide mark.

This utility model relates to the field of physical and chemical testing technology, specifically to a bending test device for dissimilar steels, comprising: a pressure head, the bottom of which forms a pressure end for contacting the upper end of the test plate, the pressure end being used to apply a bending force to the center of the test plate along its length; the device further comprises: a stop member; and a fixing assembly for detachably installing the stop member at the lower end of the pressure end. This utility model, by installing a stop member at the bottom of the existing pressure head, can pre-position the test plate using the stop member and the pressure head. When the test plate is deformed under pressure, the stop member generates a horizontal force on the test plate to prevent the test plate from shifting along its length, maintaining the center of the test plate's length on the same extension line as the pressure end of the pressure head, ensuring that the test plate is bent into a U-shape, meeting the test standards.

This application relates to the field of alloy hot working control technology, and discloses a digital twin-driven alloy hot working control method and system. The method includes: acquiring the hot working process data and the end state data of the current pass of the alloy billet; generating the microstructure evolution result of the current pass through a digital twin microstructure evolution model; comparing the microstructure state quantity with the microstructure judgment boundary in the target microstructure condition corresponding to the current pass item by item to determine the microstructure offset result of the current pass; generating the microstructure inheritance control constraint of the next pass based on the microstructure evolution result and the microstructure offset result of the current pass; screening and combining the candidate control parameters of the next pass according to the microstructure inheritance control constraint of the next pass, generating the control parameter result of the next pass, and outputting it to the hot working execution equipment to execute the next hot working; this method can improve the continuity of multi-pass hot working microstructure inheritance control and the consistency of product microstructure.

The invention discloses a phase angle measurement method, system and device based on construction of a virtual phasor, and a medium. The method comprises the following steps: obtaining an actual phasor of current sampling data of a signal; respectively moving the phase angle of the actual phasor leftwards and rightwards by the same offset phase angle, and calculating a sampling data window of the moved virtual phasor in combination with the power frequency and the frequency offset of the signal to obtain a corresponding virtual phasor; synthesizing the actual phasor and the virtual phasor to obtain a synthetic phasor calculation function, and extracting a corresponding phase angle dynamic error reduction coefficient from the synthetic phasor calculation function; calculating a phase angle dynamic error reduction coefficient through the offset phase angle; and substituting the calculated phase angle dynamic error reduction coefficient into a synthetic phasor calculation function to obtain a corresponding synthetic phasor calculation result, and obtaining a corresponding phase angle measurement result through the synthetic phasor calculation result. By adopting the technical scheme, the phase angle measurement result is more accurate, and the offset and harmonic interference of the fundamental frequency of the power grid can be effectively inhibited.

The invention relates to the technical field of metal product cutting, in particular to hardware product cutting equipment. The device comprises a workbench arranged at the top of a cabinet body, a saw blade is arranged in the center of the top of the workbench, and a pair of driving assemblies are arranged at the tops of a pair of side walls, away from each other, of the workbench; when the metal pipe is about to deviate from the interior of the clamping assembly due to extrusion force generated by cutting of the saw blade, in the process that the two driving assemblies drive the metal pipe to move towards the saw blade, the saw blade gradually cuts the metal pipe open, the saw blade generates large extrusion force on the metal pipe, and the contact portion of the metal pipe and the saw blade is blocked by the saw blade; and the part, fixed by the two clamping arms, of the metal pipe moves forwards along with the driving assembly, so that the metal pipe is about to deviate from the clamping arms. And the metal pipe between the two clamping arms can be limited by the guide rods on the two sides, and the part near the notch of the metal pipe can be blocked by the supporting assembly, so that the metal pipe is prevented from falling off from the part between the two clamping arms after being cut.

This utility model provides a photoelectric support for a conveyor line, comprising: a base, an electric telescopic rod rotatably connected to the upper end of the base, and a fixed frame fixedly installed at the upper output end of the electric telescopic rod. This photoelectric support for a conveyor line, through the arrangement of a receiving cavity, a protective shell, a sliding groove, an electric telescopic rod, a connecting block, a telescopic plate, a steering ball, and a motor, provides installation and protection space for the drive components through the receiving cavity and the protective shell. The sliding groove, in conjunction with the slider, ensures smooth rotation. The electric telescopic rod, combined with the connecting block and the telescopic plate, enables precise height adjustment and enhances structural rigidity. The steering ball and the motor enable precise electric control of the detection angle. The various structures work together to improve the flexibility and accuracy of adjustment, meeting the detection needs under different working conditions. Furthermore, multiple stabilization mechanisms reduce swaying and offset, ensuring the continuous and stable operation of the photoelectric sensor, significantly enhancing the practicality, reliability, and adaptability of the support.

The utility model relates to the technical field of thick paperboard cutting, in particular to a paperboard cutting device which comprises a conveying mechanism, a cutting mechanism and a cutting mechanism. A first moving mechanism; a second moving mechanism; the first rotating mechanism is arranged on the first moving mechanism, and the first moving mechanism is used for driving the first rotating mechanism to move up and down; the second rotating mechanism is arranged on the second moving mechanism, and the second moving mechanism is used for driving the second rotating mechanism to move up and down; the first cutting disc is arranged on the first rotating mechanism, and the first rotating mechanism is used for driving the first cutting disc to rotate; the second cutting disc is arranged on the second rotating mechanism, the second cutting disc and the first cutting disc are arranged in a coplanar mode, and the second rotating mechanism is used for driving the second cutting disc to rotate; the cutting edge included angle of the first cutting disc is larger than that of the second cutting disc. The paperboard cutting device aims at solving the problem that thick paperboards are not easy to cut in the prior art.

The invention relates to a bamboo chip curved surface cold-bending shaping device and method, and relates to the technical field of cold-bending machining.The bamboo chip curved surface cold-bending shaping device comprises a mounting plate, supporting plates are symmetrically arranged at the top of one side of the mounting plate, a rotating shaft is arranged between the supporting plates, the rotating shaft is sleeved with a roller, baffles are symmetrically arranged on the outer wall of the roller, and an H-shaped rack is further arranged at the top of the mounting plate; a plurality of rotating shafts are rotationally arranged between the inner walls of the top of the H-shaped rack, the rotating shafts are sleeved with upper rollers of different specifications, lower rollers matched with the upper rollers are rotationally arranged between the inner walls of the top of the H-shaped rack, a centering mechanism is arranged on the outer wall of the side, close to the roller, of the H-shaped rack, and stabilizing mechanisms are arranged in the H-shaped rack and located on the two sides of the rotating shafts; by means of the aluminum profile machining device, the following problems can be solved: through cooperation of an upper rotating roller and a lower rotating roller, it can be guaranteed that the bottom faces of aluminum profiles with different thicknesses are located on the same horizontal plane when the aluminum profiles enter the device; through cooperation of the arc-shaped triangular blocks and the upper roller, aluminum materials are prevented from deviating in the machining process.

A jaw position correction device is provided with a corrector (1), a retractor (20), and a correction helmet (50). The retractor (20) is provided with a pulled part (21) and a helmet fixing part (41). The correcting helmet (50) comprises a first covering part (51) for covering the front head part and the left and right head parts of the head, a second covering part (52) for covering the rear head part of the head, and a pair of left and right extending parts (54) extending downwards from the first covering part (51). A pair of left and right third covering parts (53) extending forward from the extension part (54) along the zygomatic arch part; and a first fixing part (55) for fixing the helmet fixing part (41). The pulled section (21) has: a first locking section (24) to which an upward force is applied by a first elastic member at the front end of the forward extending section (23); a second locking section (25) to which a forward force is applied by a second elastic member at the front end of the forward extending section (23); and a third locking section (27) to which an upward force is applied by a third elastic member at the rear end of the bending section (26).

The invention discloses a control method and system of a three-phase three-level AC / DC converter. A multi-parallel quasi-resonance PR control method based on time delay phase compensation is adopted in the main body control link, time delay is converted into fixed phases needing to compensate fundamental waves and high order, and the influence of time delay between sampling and output on the system is improved. Aiming at the frequency fluctuation condition of the power grid side, the real-time frequency of the power grid is updated in real time through DSOGI-FLL, a frequency value is transferred to a phase compensation link, the compensation link is calculated through a new frequency value, a new transfer function is obtained after new parameter values are calculated, the new transfer function is connected into a main body control link in series, and the self-adaptive adjustment effect is achieved.