17 results about "Third order nonlinear" patented technology

The invention provides a fullerene pyrrolidine enantiomer mediated cholesteric liquid crystal with circular polarization luminescence property and nonlinear anti-saturated absorption property, and a preparation method and application thereof. The method comprises the following steps: dissolving C60, paraformaldehyde and (R / S)-(+ / -)-alpha-methylbenzylamine in an organic solvent, and carrying out heating reflux reaction to obtain fullerene pyrrolidine enantiomer molecules; dissolving in carbon disulfide to obtain an enantiomer solution; dissolving achiral dye molecules in a solvent to obtain a dye solution; and dropwise adding the enantiomer solution and the dye solution into thermotropic liquid crystal molecules, and drying to obtain the thermotropic liquid crystal. The method is simple, the obtained cholesteric liquid crystal system shows a characteristic fingerprint texture and has a periodic spiral structure, and the doping proportion of chiral molecules is easy to adjust; the composite system has good time stability and is not prone to phase separation; the liquid crystal platform shows good circular polarization luminescence performance and third-order nonlinear optical property, and is a cholesteric liquid crystal platform with an integrated function.

The invention provides a two-dimensional formation composite sliding mode control method under an explicit convergence time limit, and relates to the technical field of automatic driving cooperative control. The method comprises the following steps: firstly, acquiring real-time motion state information of a pilot vehicle and N following vehicles, and establishing a third-order nonlinear dynamic model of each following vehicle; calculating a tracking error of the following vehicle based on the virtual vehicle strategy; dynamically processing the predetermined performance constraints; constructing a composite finite time sliding mode surface of a layered structure, and determining a total execution time limit required by convergence of all monitoring signals in the two-dimensional vehicle formation control system from an initial deviation state to a predefined steady state region; and finally, on the basis of the composite finite time sliding mode surface, an external disturbance boundary is estimated online in combination with an adaptive control algorithm, a control instruction is generated, and a monitoring signal is forced to reach a steady state in an explicit time upper boundary. The method provides a visual performance estimation means for practical engineering application, and improves the stability, rapidity and accuracy of two-dimensional formation control.

The invention discloses an anti-parameter disturbance bidirectional converter non-linear control method and system, and the method comprises the following steps: building a three-order non-linear dynamic model of a three-phase voltage source converter, defining the reciprocal 1 / Rc of an AC side resistor R and a DC side load resistor in the non-linear dynamic model as an unknown parameter, and calculating the parameter disturbance of the three-order non-linear dynamic model; obtaining a system dynamic equation with parameter uncertainty of the three-phase voltage source converter; designing a state transformation function, linearizing a system dynamic equation, and mapping a state variable x; s30, a tracking error variable is defined as a difference value between the converted state variable and a reference track of the state variable, and the difference value is used for quantifying the deviation between the actual state and the expected state of the system; defining and designing a parameter updating law of the three estimated values, and calculating and updating unknown parameters on line according to the tracking error variable; and designing and calculating a control input law based on the tracking error variable and the three estimated values, and proving the asymptotic stability of the closed-loop system through a Lyapunov function.

The application relates to a thin film electric frequency doubling device based on a band edge enhancement effect. When a fundamental wave is obliquely incident, a voltage is applied to a first electrode layer and a second electrode layer. The fundamental wave passes through the transparent first electrode layer and a thin film layer, is reflected by the second electrode layer, and then passes through the thin film layer and exits from the first electrode layer. In the process, the third-order nonlinear susceptibility is enhanced by using the band edge enhancement effect of the thin film layer, so that the generation efficiency of the second harmonic wave appears a sharp peak at a certain wavelength position. The fundamental wave wavelength corresponding to the sharp peak is just covered by the energy band of the thin film layer, so that the generation efficiency of the second harmonic wave is greatly improved under the condition of applying the voltage. Further, an extremely high modulation ratio is obtained, and the modulation depth is much higher than that of a conventional electric frequency doubling device. The thin film electric frequency doubling device based on the band edge enhancement effect disclosed in the application can realize the purpose of realizing strong modulation by using electric frequency doubling in a nonlinear material.

This invention discloses a method for estimating the speed and position of a permanent magnet synchronous motor (PMSM) based on a third-order switched extended state observer. Specifically, based on the mathematical model of the PMSM, a back-EMF observer based on a sliding mode observer is constructed to obtain the estimated back-EMF. Further, the estimated back-EMF signal is processed using a low-pass filter and amplitude normalization. The processed back-EMF is then used as the input signal to a position estimation scheme based on the third-order switched extended state observer, achieving accurate estimation of the PMSM's speed and position under different operating conditions. This invention is simple in principle and easy to implement. It combines the advantages of both third-order linear and third-order nonlinear extended state observers, improving estimation accuracy and dynamic performance while reducing the adverse effects of noise on the estimation scheme. This solves the technical problems of low estimation accuracy, high noise sensitivity, and difficulty in parameter tuning in existing estimation schemes.

This invention discloses a stable flight control method for heavy-load unmanned aerial vehicles (UAVs) with compound wing configurations, relating to the field of UAV flight control technology. This invention utilizes a third-order nonlinear ESO to unify all internal and external disturbances, such as rotor-fixed-wing coupling disturbances, wind field disturbances, and model uncertainties caused by load changes, into a total disturbance for real-time estimation and feedforward compensation. This eliminates the need for precise modeling of complex coupled aerodynamic models and load change models, significantly reducing modeling difficulty. Simultaneously, it achieves full compensation for both matched and mismatched disturbances, significantly improving the anti-disturbance capability and robustness of heavy-load compound wing UAVs under strong disturbance scenarios, and solving the problems of attitude instability under sudden load changes, coupling disturbances, and complex wind fields.

The invention relates to a one-dimensional pyrenyl organic framework nonlinear optical material as well as preparation and application thereof. The material is prepared from a pyrenyl amino monomer (Py) and different dialdehyde monomers (PTDE, PTBE and PDA) through direct Schiff base condensation reaction under a solvothermal condition, a series of one-dimensional linear organic framework material (COF) chain segments are constructed, and a thin film material is further prepared. The obtained material has highly ordered crystallinity, an expanded pi-conjugated skeleton and an obvious donor-acceptor (D-A) charge transfer channel. The one-dimensional pyrenyl D-A COF (Py-PTDE, Py-PTBE and Py-PDA) has the advantages that the one-dimensional pyrenyl D-A COF (Py-PTDE, Py-PTBE and Py-PDA) has the obvious RSA (Reverse Saturated Absorption) effect under the excitation of femtosecond laser (800 nm and 1550 nm) for the first time; compared with the prior art, in particular to a Py-PTDE material, the effective nonlinear absorption coefficient (beta eff) of the Py-PTDE material reaches 116.89 cm. GW <-1 > and 337.03 cm. GW <-1 > at 800 nm and 1550 nm respectively, so that the Py-PTDE material is obviously superior to a precursor material and another two COF materials, and shows a lower optical limiting threshold value at a near-infrared band. The excellent performance is mainly derived from more effective D-A interaction, narrower optical band gap and more efficient intramolecular charge transfer channel in the material. The material disclosed by the invention is simple in preparation method and high in repeatability, and the obtained COF film has excellent thermal stability and optical stability, can be directly used for preparing optical limiting devices and ultrafast optical response devices and can be applied to other three-order nonlinear optical fields.

The present disclosure provides an optical transceiver chip for an interferometric fiber-optic gyroscope and an interferometric fiber-optic gyroscope. The optical transceiver chip comprises: an on-chip micro-ring resonator comprising a nonlinear medium and configured to be able to couple to a pump light source and receive a pump light signal from the pump light source, and based on a third-order nonlinear effect of the nonlinear medium, generate a non-coherent wide-spectrum optical frequency comb signal from the pump light signal; a fiber coupling device configured to be coupled to the on-chip micro-ring resonator and receive the non-coherent wide-spectrum optical frequency comb signal, the fiber coupling device is further configured to be able to couple to a sensing fiber of the interferometric fiber-optic gyroscope, and provide the non-coherent wide-spectrum optical frequency comb signal to the sensing fiber of the interferometric fiber-optic gyroscope and receive a return light signal from the sensing fiber; and a photoelectric detection device configured to be coupled to the fiber coupling device, receive the return light signal and detect an interference light signal based on interference between the return light signals.

The invention discloses a multi-modal generation type artificial intelligence watermark embedding and tracing method. The method comprises the following steps: constructing a third-order nonlinear hybrid power system with fractional order Caputo derivative and time-varying Rikazi matrix closed-loop feedback at the same time; constructing a regular rattan structure which at least comprises R-Vine, C-Vine and D-Vine three-layer nesting and of which the total tree node number is not less than 4096; a finite time chaotic trajectory of a hybrid power system is subjected to spherical radial-vine Copula inverse mapping to generate an antagonistic watermark disturbance field, and meanwhile, the disturbance field is injected into an ultrahigh-dimensional singular value manifold of generative artificial intelligence output content in a nonlinear variational embedding mode. According to the method, the chaotic system and the rattan structure are combined, a watermark disturbance field with strong anti-interference is generated, effective watermark embedding and reliable traceability of the multi-mode AI content are achieved, and intellectual property ownership is guaranteed.

The application belongs to the technical field of DC-DC converter modeling, and discloses a modeling system and use method for starting of a closed-loop DC-DC converter, comprising a multi-parameter sensing module, an enhanced state space modeling module, a multi-algorithm fusion solving module, a multi-topology adaptation module and a model iteration optimization module. A three-order nonlinear model is constructed by taking the control input (duty ratio) as a new state variable, the multi-algorithm fusion solving module is used to improve the transient prediction accuracy and anti-interference ability, the enhanced state space modeling module is used to correct the model deviation, and the model iteration optimization module is used to support fast switching of multiple topologies.

This invention discloses a six-sided three-dimensional optical storage and computing integrated chip and its storage and computing method, belonging to the field of chip technology. It includes a three-dimensional storage body formed by stacking and bonding nanocrystalline materials, optoelectronic fusion chips respectively attached to the six outer surfaces of the three-dimensional storage body, a laser writing module, and a laser reading module. The six optoelectronic fusion chips constitute three pairs of face-to-face optoelectronic fusion chips, including an information input optoelectronic fusion chip pair, an information output optoelectronic fusion chip pair, and a resource retrieval and computation optoelectronic fusion chip pair. The laser writing module controls the three pairs of face-to-face optoelectronic fusion chips to emit high-frequency, high-power laser beams, changing the crystal phase of the nanocrystalline materials inside the three-dimensional storage body. The laser reading module controls the three pairs of face-to-face optoelectronic fusion chips to emit low-frequency, low-power laser beams, generating a four-wave mixed signal light. This invention uses the above-mentioned chip and its storage and computing method, utilizing third-order nonlinear optical effects and four-wave mixing to achieve uniqueness determination of information writing and reading.

This invention provides an on-chip broadband multi-source system based on silicon carbide, implemented using silicon-based silicon nitride waveguides. It utilizes third-order nonlinear optical effects, primarily degenerate four-wave mixing, to generate an optical frequency comb; and employs self-phase modulation and soliton splitting effects to generate a supercontinuum. By adjusting the voltage of the optical switch module, selective generation of the optical frequency comb or supercontinuum source can be achieved. It can generate optical frequency combs or broadband supercontinuums from visible light to mid-infrared at different frequency ranges, or simultaneously generate both, offering the advantage of multi-source output. This system is integrated onto a silicon-based chip, facilitating large-scale production and offering advantages such as small size, high flexibility, simple structure, and compatibility with other systems.

The invention relates to a digital background calibration scheme for calibrating linear and third order nonlinear gain errors of a residual amplifier (RA) in a pipelined analog-to-digital converter (ADC). According to the scheme, a customized convolutional neural network (CNN) is adopted to extract linear and third-order nonlinear gain error information of the RA, and rapid convergence is realized by injecting a jitter signal. Compared with a traditional calibration algorithm based on correlation, the method has the advantages that the convergence speed and the robustness of resisting jitter capacitor mismatch are remarkably improved. Compared with a previous calibration technology (generally used for foreground calibration) based on a neural network, the method can be operated in the background, adapts to error changes, and has no signal fidelity risk.

The present application relates to the technical field of magnetic levitation ball system, in particular to a nonlinear magnetic levitation ball system active disturbance rejection control method, in order to solve the problems of the existing magnetic levitation ball system in the off-equilibrium point working condition, such as nonlinear dynamic instability, insufficient coupling inhibition of multi-source interference, and hardware damage caused by limited control input, a new nonlinear magnetic levitation ball system active disturbance rejection control method is provided, including the following steps: 1) establishing the mechanism model of the magnetic levitation ball system under the action of voltage; 2) constructing the third-order nonlinear dynamic differential equation of the magnetic levitation ball system; 3) designing an extended state observer; 4) limiting the control input. The present application defines a new control input to reduce the complexity of the controller, and designs an extended state observer to utilize the state feedback information to design the control input, so as to realize the adjustment of the system and effectively suppress the external disturbance.

The application relates to the fields of micro-nano photonics and nonlinear optical technology, in particular to a slotted metasurface capable of enhancing third-order nonlinearity, which comprises a silicon dimer metasurface structure unit, and a quartz substrate arranged at the bottom of the silicon dimer metasurface structure unit; the silicon dimer metasurface structure unit is composed of two symmetrically arranged nanodisks, the thickness of each nanodisk is 90 nm, the radius of each nanodisk is 180 nm, and the refractive index of each nanodisk is 3.48; a slit with a width of 20 nm and a length of 60 nm is arranged on each nanodisk, and the spacing between the two nanodisks is 10 nm; ED / TD destructive interference is realized through slotted dimer design, the limitation of a traditional structure Q factor (Q>5000) is broken, the Anapole state is combined with the high nonlinear characteristic of silicon, and the THG efficiency is improved to 4.6*10 ‑4 (the highest level of similar silicon structures), and the parameter control flexibility (polarization, geometric size) provides a new paradigm for an on-chip nonlinear optical system.

The invention discloses a micro steering engine servo control method based on combination of a variable gain expansion state observer and backstepping control. Firstly, a steering engine third-order nonlinear model is established, an extended state observer is designed, and the core is to introduce a time-varying gain function L (t) to dynamically adjust the observer bandwidth. A comprehensive working condition index s is constructed by fusing normalized flight speed, incidence angle, overload and steering engine angular velocity information, and the comprehensive working condition index s is smoothly mapped into L (t) by using a hyperbolic tangent function. Under a stable working condition, the L (t) is automatically reduced to suppress noise amplification; in the event of violent maneuvers or disturbances, L (t) raises rapidly to increase the estimated speed. Furthermore, in combination with a backstepping control law, feed-forward compensation is carried out by utilizing a disturbance estimation value output by the observer, so that accurate and robust tracking of the control surface angle is realized. According to the method, the contradiction between response lag and noise sensitivity of a fixed bandwidth observer is solved, and the control performance and reliability of the micro steering engine in a full flight envelope are remarkably improved.

The application relates to a PID controller parameter optimization method of a water turbine speed regulation system, which comprises the following steps: according to a parallel PID controller structure, a three-order nonlinear object is adopted to establish a water turbine speed regulation system mathematical model; according to the water turbine speed regulation system mathematical model, an optimization objective function of the water turbine speed regulation system under no-load working conditions or load working conditions is established; according to the optimization objective function and the constraint range of the PID controller parameters, an improved sparrow search algorithm is adopted to optimize the PID controller parameters, and optimal PID controller parameters are output, wherein the improved sparrow search algorithm introduces a water hammer coefficient in the producer search step length of a basic sparrow search algorithm and adopts boundary adsorption combined with gradient correction instead of random disturbance. The application realizes global optimization and engineering adaptation of PID parameters, and effectively improves the control performance and operation stability of the speed regulation system under all working conditions.