45 results about "Third wave" patented technology

The invention provides a three-dimensional holographic imaging method. The method comprises the following steps: loading a holographic pattern to be imaged to a spatial light modulator; modulating a preset laser source by using a spatial light modulator loaded with a holographic pattern to form a first wavefront with initial phase information; carrying out primary scattering on the first wavefront by adopting a first turbid medium lens to form a second wavefront; compensating the second wavefront by adopting a metasurface compensation unit to form a third wavefront; after a second turbid medium lens is adopted to carry out secondary scattering on the third wavefront, a holographic imaging system is utilized to carry out imaging; wherein the metasurface compensation unit is determined according to a transmission matrix of the first turbid medium lens and a transmission matrix of the second turbid medium lens. The imaging view angle can be effectively increased, and the space bandwidth product can be improved.

The application discloses a wave divider, a wave combiner and an optical communication device, and belongs to the technical field of optical communication. The wave divider comprises a first filter device and a second filter device. The first filter device is used for dividing an input light beam into a first light beam and a second light beam, the first light beam is light of a first wave band, the second light beam comprises light of a second wave band and light of a third wave band, and the first wave band is located between the second wave band and the third wave band. The second filter device is used for dividing the second light beam into a first sub-light beam and a second sub-light beam, the first sub-light beam is light of the second wave band, and the second sub-light beam is light of the third wave band. The width of a first transition wave band range of the first filter device is less than the width of a second transition wave band range of the second filter device, and the first wave band at least partially coincides with the second transition wave band range. The wave combiner has the same device composition as the wave divider, and the transmission process of light is the reverse process of the wave divider. The wave divider and the wave combiner can improve the utilization rate of light.

A coated tool includes a base body and a coating film. The coated tool has a first surface with a rake face, a second surface with a flank face, and a third surface located between the first surface and the second surface and being a C surface or an R surface. The coating film includes a first coating film located on the first surface and / or a second coating film located on the second surface, and a third coating film located on the third surface. A wavenumber of a maximum Raman peak of the first coating film is a first wavenumber, a wavenumber of a maximum Raman peak of the second coating film is a second wavenumber, and a wavenumber of the maximum Raman peak of the third coating film is a third wavenumber. The third wavenumber is smaller than the first wavenumber and the second wavenumber.

The invention belongs to the field of polarization measurement, and particularly relates to a space solar spectrum magnetic field telescope based on multi-wave-plate polarization modulation, which comprises a telescope system, a relay system and a spectrum imaging system, the telescopic system comprises a first 1 / 2 wave plate, a 1 / 4 wave plate and a second 1 / 2 wave plate; when neither the first 1 / 2 wave plate nor the second 1 / 2 wave plate fails, the second wave plate is kept static, and the first wave plate and the third wave plate rotate in the same direction according to a preset different-speed asynchronous motion time sequence, so that the full-stokes component of the solar polarization spectrum is measured; when any one of the first 1 / 2 wave plate and the second 1 / 2 wave plate breaks down, the 1 / 4 wave plate is started, and the 1 / 4 wave plate and the other normally working 1 / 2 wave plate rotate in the same direction according to the re-planned different-speed asynchronous motion time sequence, so that the measurement of the full stokes component of the solar polarization spectrum is maintained. According to the invention, full Stokes measurement can be realized, and the blank of space solar vector magnetic field detection capability in China is filled.

Disclosed is a phase measurement device, comprising: a first wave plate, a first polarization splitting prism, a fourth wave plate, a retroreflector, a third wave plate, a reflector, a second wave plate, a polarizer, a second polarization splitting prism, a third polarization splitting prism, a first photoelectric detector, a second photoelectric detector, and a base, wherein the first to third polarization splitting prisms and the first and second photoelectric detectors are fixed on the base; the first to fourth wave plates are respectively arranged around the periphery of the first polarization splitting prism; the polarizer is arranged on an emitting surface of the third polarization splitting prism; the retroreflector is arranged on an outer side of the fourth wave plate; and the reflector is arranged on an outer side of the third wave plate. An interferometric signal is resolved to obtain a measurement light beam phase.

The present invention discloses an automatic proportional-integral pressure controller, which drives the rotation of a floating plate based on the pressure difference between the actual pressure in the air chamber and the preset pressure, and converts the rotation of the floating plate into the up and down movement of the baffle to adjust the distance between the baffle and the nozzle, thereby changing the output air pressure of the pneumatic amplifier and converting the movement of the mechanical structure into air pressure changes. The output air pressure change controls the opening and closing state and opening degree of the intake valve or exhaust valve, thereby controlling the intake or exhaust of the air chamber; on the other hand, it is transmitted to the third wave spring assembly and the second wave spring assembly. Under the buffering effect of the air storage chamber, the air pressure change of the second wave spring assembly lags, and the pressure difference change between the two plays a feedback regulating role in the rotation of the floating plate. Automatic proportional-integral control of air pressure is achieved by two sets of wave spring assemblies, with fast response speed and high control accuracy. It adopts a purely mechanical structure design with strong anti-interference ability, and the overall structure is simple and easy to assemble and operate.

The invention discloses a double-emission-source delay time calculation method and device, equipment and a medium, and the method comprises the steps: firstly, setting that only a far emission source works, obtaining a first wave train of a casing wave excited by the far emission source and received by a first receiver, and obtaining a second wave train of the casing wave excited by the far emission source and received by a second receiver; then calculating a first moment when the head wave in the first wave train arrives and a second moment when the head wave in the second wave train arrives, and then obtaining a third wave train of the casing wave excited by the near-emission source and received by the first receiver and a fourth wave train of the casing wave excited by the near-emission source and received by the second receiver; and calculating a third moment when the head wave in the third wave train arrives and a fourth moment when the head wave in the fourth wave train arrives, thereby calculating the delay time of the double emission sources. The time difference between the head waves of the casing waves excited by the far emission source and the near emission source and the receiver is used as the emission delay time, so that the calculation complexity of the delay time of the double emission sources is effectively reduced.

The invention discloses a detuning aberration reconstruction method and device in complex cylindrical surface pseudo-shear interference detection, and the method comprises the steps: firstly obtaining first wavefront data of a cylindrical mirror to be detected, which is measured by an interferometer, and second wavefront data detected by the interferometer after the cylindrical mirror to be detected moves once in the curvature direction when interference fringes are zeroed; the third wavefront data is detected by the interferometer after the cylindrical mirror to be detected moves once again along the curvature direction; the method comprises the following steps of: firstly, obtaining first-order differential data without maladjustment aberration by using the three wavefront data, then obtaining second-order differential data without maladjustment aberration by using the three wavefront data, then generating first-order differential maladjustment aberration-free wavefront data by using the second-order differential data, and finally obtaining maladjustment aberration generated by the cylindrical mirror to be measured moving along the curvature direction based on the first-order differential maladjustment aberration-free wavefront data. Thus, by reconstructing the maladjustment aberration, the accuracy of the differential wavefront data used when the cylindrical surface shape is reconstructed can be ensured, and the reconstruction precision of the cylindrical surface shape error is further improved.

The application discloses a corrugated plate spacing adjusting device, which comprises a guide fixing seat, a first wave crest clamping mechanism, a second wave crest clamping mechanism, a third wave crest clamping mechanism and a wave crest clamping groove. The first wave crest clamping mechanism, the second wave crest clamping mechanism and the third wave crest clamping mechanism are supported by the guide fixing seat, and the wave crest clamping groove is matched with the wave crest clamping mechanism to accommodate the wave crest of the corrugated plate, so that independent clamping of the wave crest of different corrugated plates is realized. The relative positions of the first wave crest clamping mechanism, the second wave crest clamping mechanism and the third wave crest clamping mechanism are moved, the distance between two corrugated plates is adjusted, the joint width of the two corrugated plates is synchronously adjusted, a plurality of wave crest clamping mechanisms are matched to prevent the corrugated plates from being separated, a stable supporting structure is provided, and the continuity and safety of assembly work are improved.

The application provides a dynamic pressure gas thrust bearing, a rotor assembly and a compressor. The dynamic pressure gas thrust bearing comprises a bearing shell (25), a top foil (21) fixed at one end on the bearing shell (25) and movable at the other end relative to the bearing shell (25), a wave foil mounting space formed between the top foil (21) and the bearing shell (25), a first wave foil (22), a second wave foil (23) and a third wave foil (24), the first wave foil (22), the second wave foil (23) and the third wave foil (24) are sequentially and spacedly arranged in the wave foil mounting space along the airflow direction, and the rigidity of the first wave foil (22) and the third wave foil (24) is greater than that of the second wave foil (23). According to the dynamic pressure gas thrust bearing, a secondary wedge structure can be formed on the surface of the top foil at high speed, and the carrying capacity and adaptive capacity of the bearing in a high-speed environment can be improved.

The utility model relates to the technical field of corrugated boards, in particular to a corrugated board with a honeycomb structure, which mainly solves the problems of low longitudinal compressive strength and poor buffering performance of a honeycomb paperboard in the prior art, and comprises a corrugated board body which comprises a surface layer, a middle layer and a bottom layer, the surface layer comprises a first surface layer, a second surface layer with a wave structure and a third surface layer with a wave structure, the second surface layer is provided with a second wave crest and a second wave trough, the third surface layer is provided with a third wave crest and a third wave trough, the lower surface of the second wave trough is compositely connected with the upper surface of the third wave trough, and the amplitude of the second wave crest is larger than that of the third wave crest; a plurality of grooves are concavely formed in the upper surface of the middle layer, the upper surface of the middle layer is in composite connection with the lower surface of the third surface layer, the third troughs are embedded in the grooves, and the upper surface of the bottom layer is in composite connection with the lower surface of the middle layer.

The invention belongs to the technical field of rubber mat connection of plate heat exchangers, and provides an anti-degumming rubber mat for a heat exchange plate. The anti-degumming pad comprises an anti-degumming pad main body and a sheet main body, the plate sheet main body is arranged on the anti-degumming pad main body and is used for being matched with a hanging groove in a heat exchange plate; the anti-degumming pad main body is provided with a first connecting arm and a second connecting arm; wherein the first connecting arm and the second connecting arm are arranged on one side of the anti-degumming mat main body; the plate sheet main body is provided with a rubber mat groove, a first wave crest, a first wave trough, a first connecting arm groove, a second wave crest, a second wave trough, a second connecting arm groove and a third wave crest; the rubber mat main body is connected with the first connecting arm and the second connecting arm; the rubber mat main body is arranged in the rubber mat groove; the first connecting arm groove and the second connecting arm groove are formed in the outer side of the rubber mat groove; the thickness of the rubber mat groove is equal to the thickness of the first connecting arm and the second connecting arm after compression; the first wave crest, the first wave trough, the second wave crest, the second wave trough and the third wave crest are sequentially arranged along the outer side wall of the plate sheet body.

The light splitting device comprises a first light splitting piece, a first wave plate, a magneto-optical crystal, a Wollaston prism, a second wave plate, a third wave plate and a second light combining piece which are arranged along a light path, the first wave plate is arranged on one light path after light splitting of the first light splitting part so as to ensure that the polarization state of linearly polarized light input into the magneto-optical crystal is kept consistent; the second wave plate and the third wave plate are respectively arranged in one of emergent light paths of the Wollaston prism; and a coil is arranged outside the magneto-optical crystal. According to the utility model, through currents of different magnitudes, the coil generates magnetic fields of different magnitudes, the magnetic fields of different magnitudes generate different rotation angles, the different rotation angles correspond to different sin2theta and cos2theta, and furthermore, through the Wollaston prism, two polarization states have light splitting of different proportions. And two beams of light with different splitting ratios are formed after beam combination.

A waveguide structure. In some embodiments, the waveguide structure, includes: a first waveguide (105), a second waveguide (120), and a third waveguide (125) on a substrate (115). The first waveguide (105) may be at a different height than the second waveguide (120). The waveguides may be configured to cause light to couple between the first waveguide (105) and the second waveguide (120), and between the second waveguide (120) and the third waveguide (125). The first, second, and third waveguides (105, 120, 125) may be composed of respective materials having a first index of refraction, a second index of refraction, and a third index of refraction respectively. The third material may include silicon and nitrogen. The second index of refraction may be greater than the first index of refraction, and less than the third index of refraction.

A liquid ejection head includes nozzles, pressure chambers communicating with the nozzles, volumes thereof being varied to eject liquid through the nozzles, an actuator varying the volumes according to drive waveforms respectively applied to the chambers, a signal processing circuit configured to, upon receipt of an instruction, acquire first data indicating first waveforms and second data indicating second waveforms, and determine third waveforms based on differences between the first and second waveforms, the third and second waveforms being applied to the chambers at first and second timings, and a drive circuit configured to output the drive waveforms generated by the signal processing circuit to the pressure chambers. One of the third drive waveforms is different from or identical to a corresponding one of the first drive waveforms depending on whether said one of the first drive waveforms and a corresponding one of the second drive waveforms match a predetermined pattern.

The application provides a fin and a heat exchanger with the same, the fin comprising: a first connecting section, a second connecting section and a third connecting section, the second connecting section being used for bending, the second connecting section having oppositely arranged first and second connecting ends, the first connecting end being arranged on the side of the second connecting end away from the third connecting section; along the length direction of the second connecting section, the second connecting section is in a straight strip structure before bending, and is in an arc strip structure after bending; the first, second and third connecting sections are all in a corrugated structure, the first connecting section has a first wave distance Fp1, the second connecting section has a second wave distance Fp2, and the third connecting section has a third wave distance Fp3; wherein, Fp2>Fp1 and Fp2>Fp3. Through the technical scheme provided by the application, the technical problem that the fin is inconvenient to bend in the prior art can be solved, the heat exchange performance of the product can be improved, the heat exchange area can be increased, and the corrosion resistance of the product can be improved.

The invention discloses an optical module. An absolute value of a wavelength interval between a first optical signal and a second optical signal is located in a first preset range. The light receiving component comprises a first lens and a light splitting assembly. The light splitting assembly comprises a substrate, a first wave plate, a second wave plate and a third wave plate, the first wave plate is located between the light emitting component and the first lens so that the first optical signal can be reflected and the second optical signal can be transmitted. The second wave plate is located on a reflection light path of the first wave plate, and the third wave plate is located between the second wave plate and the light receiving assembly. The first shell is provided with a storage groove, an adhesive layer is arranged between the first lens and the bottom face of the first shell, the thickness of the adhesive layer is located in a second preset range, and the difference value between the size of the storage groove and the size of the first lens is larger than a preset value so that the first lens can be actively coupled and attached to the first shell. The first lens is mounted on the first shell in an active coupling mode so as to adjust the optical signals reflected and transmitted by the first wave plate, so that the first optical signals and the second optical signals are separated.

The application relates to the lighting technical field, and particularly discloses a full-spectrum light source and a manufacturing method and application. The full-spectrum light source comprises a light source chip and encapsulating glue, and the encapsulating glue is mixed with compounded fluorescent powder; the light source chip is a first waveband piece with an emission peak value of 410-420 nm, a second waveband piece with an emission peak value of 430-440 nm, a third waveband piece with an emission peak value of 445-460 nm and a fourth waveband piece with an emission peak value of 465-475 nm; and the compounded fluorescent powder is blue-green fluorescent powder with an emission peak value of 490-500 nm, green fluorescent powder with an emission peak value of 525-535 nm and red fluorescent powder with an emission peak value of 650-660 nm. The full-spectrum light source has full coverage of 380-780 nm, good spectral continuity, no obvious wave peak and wave trough, uniform spectral proportion without serious disorder, strong color rendering and close to the sunlight spectrum.

The invention discloses an inverter switching time test method and device, equipment and a storage medium. The method comprises the following steps: acquiring a target power value, controlling the operation of electrical equipment based on the target power value, and putting a reactive load into work; respectively acquiring a first waveform and a second waveform of an alternating current input end and an alternating current output end of the inverter by utilizing acquisition equipment; after the contactor is disconnected, acquiring a third waveform and a fourth waveform of the alternating current input end and the alternating current output end of the inverter respectively by utilizing acquisition equipment; and obtaining an inverter input waveform based on the first waveform and the third waveform, obtaining an inverter output waveform based on the second waveform and the fourth waveform, and determining the switching time of the inverter according to the inverter input waveform and the inverter output waveform. According to the scheme, the dynamic characteristics of the switching process are precisely restored through dual-channel waveform acquisition, the response capability and the switching performance of the inverter in a power-off scene are effectively evaluated, and the method is suitable for performance testing of scenes such as a distributed optical storage system and household emergency power supply.

The invention provides a method and a device for determining the state of charge of a flow battery. Emitting multi-band detection laser to the electrolyte in the flow channel of the flow battery, and synchronously collecting scattered light signals and fluid parameters after being scattered by the electrolyte; determining a basic state of charge according to a first spectrum characteristic value of the second wave band laser in the collected scattered light signal; determining hydrodynamic characteristics according to the flow velocity and the viscosity, and correcting the basic state of charge by using the hydrodynamic characteristics to determine a first state of charge; determining the temperature of the electrolyte according to the spectral response difference characteristics of the first wave band laser and the third wave band laser in the scattered light signal; determining the concentration of the electrolyte according to a second spectrum characteristic value of the second wave band laser in the scattered light signal; and determining a target state of charge of the flow battery according to the first state of charge, the temperature of the electrolyte and the concentration of the electrolyte. Therefore, the accuracy of determining the charge state of the flow battery is improved.

Examples of fault location in a power transmission line connecting a first and a second terminal is described. In an example, arrival times of a first peak, a second peak, and a third peak of a travelling wave detected from measurements carried out at the first and second terminals is detected. A rise time associated with the first peak of the travelling wave is calculated. One of a first half and a second half of the power transmission line is identified, as having a fault, based on a comparison of the rise time. One of a first segment, a second segment, a third segment, and a fourth segment of the power transmission line is identified as having the fault. Length of the power transmission line is estimated. The fault location is estimated based on identification of one of the first, second, third, and fourth segments as having the fault.

An object detector includes a wave transmitter to transmit a modulated wave in a predetermined frequency range to an object, a first wave receiver to receive sound waves and to generate a first wave reception signal indicative of the reception of the sound waves, a second wave receiver to receive sound waves and to generate a second wave reception signal indicative of the reception of the sound waves, an adder to generate a third wave reception signal by adding the first and second wave reception signals, and a controller to detect the object based on the third wave reception signal by causing the wave transmitter to transmit the modulated wave. The second wave receiver is farther from the wave transmitter than the first wave receiver. A fluctuation range of the third wave reception signal is not greater than a fluctuation range of the first wave reception signal.

The invention discloses a display device comprising a display used for emitting light of a first wave band, a second wave band and a third wave band; the light splitting structure is positioned on the light emitting side of the display and is used for partially reflecting and partially transmitting the incident light; and the narrowband reflecting layer is located on a light emitting path of the light splitting structure, and the narrowband reflecting layer is used for reflecting light of the first wave band, the second wave band and the third wave band and transmitting light of other wave bands. The narrow-band reflecting layer only reflects the light rays of the wave band emitted by the display, so that the display light rays can be emitted into human eyes as much as possible, the utilization rate of the light rays emitted by the display is improved, the brightness of a display picture observed by the human eyes is further improved, meanwhile, more ambient light rays can be emitted into the display device, and the display effect is improved. And the brightness of a real picture observed by human eyes is improved, so that the watching experience of a user is improved.

A separation device for a friction plate group relates to the field of friction plate groups of clutches. The present invention aims to solve the problems of low axial positioning accuracy of friction elements in existing wet friction clutches, which leads to large clutch drag torque, and poor clutch maintainability and low power density due to the use of cylindrical coil springs and guide rod separation in dry friction clutches. In the separation device for a friction plate group described in the present invention, an end plug is sealed at the head end of the involute gear ring of the clutch, a retaining ring is located between the end plate of the clutch and the flange, and is in close contact with the flange, an outer ring of the retaining ring is interference-fitted with an inner ring of the involute gear ring, a first wave spring is provided between the end plug and the first friction plate of the clutch, and the end plug and the first wave spring are fixedly connected, a second wave spring is provided between two adjacent friction plates of the clutch, and between the rear friction plate of the clutch and the retaining ring, and a third wave spring is provided between two adjacent plates of the clutch.

The invention relates to the satellite internet technology, and provides a user service guarantee method, device and equipment, and the method comprises the steps: obtaining a first satellite set corresponding to a target user; determining a first wave position of the target user corresponding to each first satellite in the first satellite set, and forming a first wave position set corresponding to the target user; according to the first satellite set and the first wave position set, identifying a second satellite set and a second wave position set corresponding to the target user; acquiring a third satellite and a third wave position corresponding to the target user from the second satellite set and the second wave position set; adjusting the beam position priority of the third beam position according to the user priority of the target user; and adjusting the third satellites corresponding to the remaining second wave positions in the second wave position set. According to the embodiment of the invention, service guarantee can be carried out on users (especially high-priority users) with different service priorities.

The present application relates to the technical field of optical communication, and in particular to a wave splitter and a communication module. The wave splitter comprises a shell and a wave splitting assembly. A public port is formed on one side wall of the shell. First, second and third receiving ports are formed on two side walls adjacent to the public port. The wave splitting assembly comprises a pentagonal prism and first, second and third filters. An optical signal enters the pentagonal prism through the public port, is reflected and enters the first filter. The first filter filters out optical signals of a first wavelength and emits them through the first receiving port. The remaining optical signals are reflected and enter the second filter. The second filter filters out optical signals of a second wavelength and emits them through the second receiving port. The remaining optical signals are reflected and enter the third filter. The third filter filters out optical signals of a third wavelength and emits them through the third receiving port. The above structure reduces the loss of optical signals and improves the reliability of wave splitting.

The invention provides an optical module which comprises a wave division assembly, a first reflection sheet, a first reflection piece and a second reflection piece, the wave division assembly comprises a first substrate, a first wave plate, a second wave plate, a third wave plate, a fourth wave plate, a fifth wave plate, a sixth wave plate, a seventh wave plate and an eighth wave plate, the fifth wave plate is located on a transmission light path of the first wave plate, and the sixth wave plate is located on a transmission light path of the eighth wave plate. The second wave plate is located on a reflection light path of the fifth wave plate, the sixth wave plate is located on a reflection light path of the second wave plate, the third wave plate is located on a reflection light path of the sixth wave plate, the seventh wave plate is located on a reflection light path of the third wave plate, the fourth wave plate is located on a reflection light path of the seventh wave plate, and the eighth wave plate is located on a reflection light path of the fourth wave plate; the first reflection sheet is located between the second wave plate and the second light receiving assembly, the first reflection piece is located between the seventh wave plate and the first light receiving assembly, the second reflection piece is located between the eighth wave plate and the third light receiving assembly, and received light signals are reflected and transmitted among the multiple wave plates so as to achieve wave splitting.

The utility model provides a projector, which can reduce the number of parts and restrain large scale in a three-plate type projector. In the projector of the utility model, first light of a first wave band emitted from a first light source sequentially passes through a first light guide element and a first parallelization element and then enters a light synthesis element. Second light of a second wave band emitted from the second light source sequentially passes through the second light guide element and the second parallelization element and enters the light synthesis element. Third light of a third wave band emitted from the third light source sequentially passes through the third light guide element and the third parallelization element and enters the light synthesis element. A first focal length of the first parallelization element is longer than a first length from a first incident end to a first exit end of the first light guide element, and a second focal length of the second parallelization element is longer than a second length from a second incident end to a second exit end of the second light guide element. A third focal length of the third parallelization element is longer than a third length from a third incident end to a third exit end of the third light guide element.

The invention relates to a resource management technology of a satellite internet, and provides a non-ground user-oriented beam position planning method, device and equipment, and the method comprises the steps: obtaining a first satellite set corresponding to a target non-ground terminal; determining a first wave position of the target non-ground terminal corresponding to each first satellite in the first satellite set, and forming a first wave position set corresponding to the target non-ground terminal; according to the first satellite set and the first wave position set, identifying a second satellite set and a second wave position set corresponding to the target non-ground terminal; and acquiring a third satellite and a third wave position corresponding to the target non-ground terminal from the second satellite set and the second wave position set. According to the embodiment of the invention, the service guarantee of non-ground users in the satellite internet can be improved on the premise of not influencing the normal operation of the satellite internet.

The application provides a method and device for determining an inertia time constant of a generator set. The method comprises: performing step disturbance on a terminal voltage of a to-be-tested generator based on a first inertia time constant and a first preset threshold, amplifying a synthesized mechanical power integral of a power system stabilizer by a first preset coefficient, and recording a first waveform diagram to obtain a first target value based on a first pole value of the first waveform diagram; updating the first inertia time constant based on a preset adjustment step and the first target value to obtain a second inertia time constant, and then determining a second waveform diagram and a second target value; correcting the second inertia time constant based on a preset adjustment step, the first target value and the second target value to obtain a corrected inertia time constant, and then determining a third waveform diagram and a third target value; and obtaining a target inertia time constant when an absolute value of the third target value is less than or equal to a second preset threshold. The method solves the problem of a large error of a unit inertia time constant in the prior art.