169 results about "Characteristic equation" patented technology

The invention discloses a disc type permanent magnet motor control method and system with adaptive dead zone compensation, and the method comprises the steps: constructing a state equation, a state estimation equation and a state-space equation of a permanent magnet synchronous motor through the structure of a Luenberger observer, constructing an observable matrix through an output matrix and a system matrix, and verifying the output of an observable system; establishing a characteristic equation to enable the designed observer to be finally converged, reducing an error between an estimated value of the disturbance observer and an actual value of the system, and realizing digital control of an actual servo platform through a discrete observable matrix; a phase-A bridge arm of an inverter is analyzed, three-phase current is subjected to Fourier decomposition, and stator harmonic components are analyzed to obtain three-phase harmonic current of the motor; an adaptive filter is designed based on an NLMS algorithm, and an online dead-zone compensation strategy is improved for a dead-zone effect. According to the method, by introducing the Luenberger disturbance observer, real-time measurement and adjustment of a nonlinear system can be realized, so that the performance index of the system is effectively improved.

The invention provides a quality evaluation method of fresh corn. The quality evaluation method comprises the following steps: step 1, treating the fresh corn by adopting different blanching modes; step 2, selecting a plurality of evaluation indexes to respectively measure the fresh corns treated by different blanching modes; step 3, screening a variation coefficient gt; 15% of evaluation indexes are used as key quality indexes; step 4, carrying out data standardization processing on the screened key quality indexes; 5, performing principal component analysis on the key quality indexes by adopting SPSS data analysis software, and calculating the weighted variance contribution rate of each principal component; 6, calculating the coefficient of each key quality index; step 7, obtaining a characteristic equation of each principal component; and step 8, accumulating the product of the feature vector of each principal component in the blanching mode and the contribution rate of the weighted variance of the corresponding principal component to obtain the comprehensive quality score of the fresh corn in the blanching mode.

The invention discloses a multi-branch hydro-generator stator grounding fault active arc extinction method, which comprises the following steps: S1, constructing an analytic function of a double-frequency fault potential by using a neutral point and a generator end voltage after a generator fault and combining a winding connection sequence; s2, deriving a linear constraint relation between a third harmonic fault potential real part and an imaginary part; s3, according to the linear constraint relation, in combination with the potential expression of each branch winding of the third harmonic, constructing a target function for fault solution, and solving a solution set based on the third harmonic characteristic quantity; s4, according to the fundamental wave fault characteristic equation, constructing a fundamental wave difference coefficient multi-solution screening criterion, and obtaining a unique solution of the double-frequency fault potential; s5, aiming at the multi-branch hydro-generator, constructing a neutral point dual-frequency power supply injection amount calculation formula; and correctly adjusting the injection amount of the neutral point double-frequency controllable power supply by using the screened double-frequency fault potential unique solution, and suppressing the voltage of the fault point to be 0 to realize arc extinction. According to the invention, reliable arc extinction of the multi-branch hydraulic generator can be realized.

The invention relates to an operation debugging method and device of a pump set system, and belongs to the field of pressure supply medium equipment. Calculating the pipeline impedance coefficient of the pipeline between the nodes under the rated flow; respectively determining a valve impedance coefficient and an equipment impedance coefficient; establishing a pump set performance equation according to the pump set performance curve; establishing a flow distribution mathematical model according to the principle that flow conservation and parallel branch pressure drop are the same; calculating the flow distribution coefficient of each pipeline according to the pipeline impedance coefficient, the valve impedance coefficient and the equipment impedance coefficient, and establishing a system main pipeline characteristic equation; the main pipeline characteristic equation and the pump set performance equation are combined, and a pump set operation condition point is calculated; calculating the pressure of each node according to the operating condition point of the pump set and the flow coefficient of each pipeline; and the valve opening is calculated according to the pressure and flow requirements of all the nodes, and debugging is conducted by controlling the valve opening. The method can effectively reduce the calculation duration and the calculation amount.

The invention belongs to the technical field of new energy power systems, and discloses a net-building type converter parameter simulation analysis method, system, equipment and medium, and the method comprises the steps: building an equivalent transfer function and a damping torque model of a net-building type converter based on a damping torque theory, and defining a damping torque and a synchronous torque through the generation and conversion of a characteristic equation; establishing a converter voltage-current relational expression based on the dynamic equation of the grid-forming converter, and deducing a damping torque of the grid-forming converter containing a complete control loop through linearization processing of the relational expression; and simulating the damping characteristics of the network-forming converter containing the complete control loop, and evaluating the influence degree of the outer loop control parameters on the damping torque by analyzing the damping torque under different outer loop bandwidths. The invention provides the damping torque model for optimizing the network construction type outer ring control parameters, so that modeling of a complex feedback link in a damping torque equivalent model is avoided, and a brand new thought is provided for analyzing the outer ring control parameter optimization problem.

The invention discloses a fractional derivative-based virtual inertia control and controller parameter setting method, which comprises the following steps of: obtaining a characteristic equation of a system according to a transfer function from system interference to system frequency response; obtaining a real root boundary curve RRB and a multiple root boundary curve CRB according to a characteristic equation of the system; dividing the virtual inertia-virtual damping plane according to the boundary curve to obtain a stable region in which the system is kept stable in the parameter plane; obtaining an optimal control parameter of a fractional order virtual controller FOVIC according to the stable region; the controller output reference power is obtained according to the optimal control parameters; and according to the controller output reference power, the active power adjustment amount of the primary frequency modulation of the battery energy storage system is obtained through inner loop control of a GFL power converter. According to the method, the frequency deviation can be better suppressed, the robustness of the system is enhanced, and a quick frequency regulation service is provided for a low-inertia power grid integrated with renewable energy sources.

The invention relates to the technical field of physical acoustics, in particular to a saturated porous medium metasurface Portrait wave frequency dispersion relation calculation method and system, and the method comprises the following steps: obtaining expressions of solid skeleton displacement, fluid relative displacement, total stress, solid shear stress and pore pressure under the action of Portrait waves; obtaining an expression of a fluid displacement component and a fluid normal stress; obtaining an expression about the relative motion of the resonator; according to all the expressions, stress and displacement continuity boundary conditions are applied to the interface of the saturated porous medium and the fluid layer, a characteristic equation of frequency dispersion characteristics is obtained and solved, and a frequency dispersion curve is obtained. According to the method, the explicit frequency dispersion relation of the saturated porous medium metasurface portrait waves is provided, the calculation efficiency and prediction precision of complex interface wave propagation are improved, the optimal design of the metasurface resonator array can be guided, and a key theoretical tool and technical support are provided for design of high-performance acoustic functional devices and structures.

The invention discloses a design method of a pressure control throttle valve with the pressure drop linearly changing along with the stroke, and belongs to the technical field of automation of oil and gas exploitation equipment.The design method comprises the following steps that the linear relation between the pressure drop and the stroke of the throttle valve serves as a target; a mathematical model of a valve element contour is established by establishing a minimum throttling area equation of a cylindrical valve and a wedge-shaped valve, correcting a flow pressure drop characteristic equation and deducing a differential pressure linear adjustment equation, a valve element contour curve meeting the linear requirement is deduced through variable-diameter contour optimization design, and therefore the valve element structure of the throttling valve is obtained. By means of the design method, the valve element contour curve with the wider linearity range of pressure control adjustment and the better precision can be obtained, and the design method is more efficient and universal.

The invention discloses an ocean vortex three-dimensional flow field reconstruction method based on physical constraints, and belongs to the technical field of physical oceanography and data modeling, and the method comprises the steps: calculating sea surface height abnormal data according to climate state data and sea surface observation data, recognizing vortex features, and dividing a vortex into grid points; according to the climate state data and the vortex vertical mode characteristic equation, constructing a vortex vertical mode function, and obtaining a vortex horizontal flow velocity vertical structure function; by taking the sea surface flow velocity abnormal condition and the deep layer flow velocity abnormal condition as constraints, determining a vortex vertical modal coefficient according to a vortex horizontal flow velocity vertical structure function, and reconstructing a vortex horizontal flow velocity vertical structure at each grid point; and superposing the vortex horizontal flow velocity vertical structure and the climate state horizontal flow velocity vertical structure to obtain a seawater horizontal flow velocity vertical structure to construct a vortex three-dimensional flow field structure. The problems that the prior art is limited to the sea surface, and the vertical structure of the vortex is difficult to accurately describe are solved.

The invention relates to a calculation method and system for a non-load structural design value of the early temperature of a wall, and belongs to the technical field of construction control. The calculation method comprises the steps that geometric parameters, material parameters, environmental parameters and hydration heat parameters of a concrete continuous wall are obtained; according to the material parameters, a thermal diffusion coefficient is calculated, and a heat production rate function changing along with time is generated; based on the geometric parameters, the material parameters and the environmental parameters, calculating a Pitot number, and defining dimensionless coordinates and dimensionless time; solving the characteristic equation according to the Pitot number to obtain a characteristic value sequence and a corresponding vibration mode function sequence; calculating a weight coefficient of each mode based on the initial temperature distribution and the vibration mode function sequence; and solving a time domain ordinary differential equation and applying convolution integration, generating a time-varying modal amplitude function sequence, synthesizing a dimensionless temperature field, determining a convergence solution through a truncated modal number, and converting the dimensionless temperature field into a physical temperature field for output. The early temperature gradient distribution rule of the wall can be accurately captured.

The invention discloses a parameter setting method and device for a grid-connected double-fed wind power plant, and the method comprises the steps: building a full-order linear state space model based on the interaction behaviors of N fans in the grid-connected double-fed wind power plant and a power grid, and N is a positive integer; performing equivalent order reduction processing on the basis of the full-order linearization state space model to obtain N independent single grid-connected doubly-fed fan equivalent subsystem models; according to the N mutually independent single grid-connected doubly-fed fan equivalent subsystem models, constructing a dynamic characteristic equation of a grid-connected doubly-fed wind power plant under a direct-current voltage control time scale; and performing stability judgment on the dynamic characteristic equation of the grid-connected double-fed wind power plant to obtain the parameter setting method suitable for the grid-connected double-fed wind power plant under the slow time scale. According to the method, the analysis calculation amount is effectively reduced, the efficiency and feasibility of small-interference stability analysis of the wind power plant are remarkably improved, and complex large-scale wind power plant analysis is more efficient.

The invention relates to the technical field of composite material structure dynamics analysis, and provides a method and system for predicting the inherent frequency of a three-phase functionally graded composite material conical plate, and the method comprises the steps: employing an improved Halpin-Tsai model to calculate the equivalent parameters of a GPL-containing two-phase composite matrix, solving the equivalent parameters of a three-phase composite layer, and calculating the inherent frequency of the three-phase composite material conical plate. The method comprises the following steps: constructing a nonlinear geometrical relationship between a displacement field and a strain field, calculating a stiffness coefficient of each layer, constructing kinetic energy of the three-phase composite material conical plate, calculating an energy coefficient according to the stiffness coefficient of each layer, constructing potential energy of the conical plate according to the energy coefficient, and constructing a modal displacement function by adopting a Chebyshev polynomial and a boundary function. And establishing a characteristic equation based on a minimum potential energy principle and solving to obtain the inherent frequency of the three-phase composite material conical plate. According to the method, efficient calculation of the inherent frequency of the three-phase composite material conical plate is achieved, and the reliability and engineering application value of structural dynamics analysis are remarkably improved.

The invention discloses a spacecraft component layout optimization method considering rotational inertia and vibration frequency, which comprises the following steps of: presetting boundary dimensions of a spacecraft cabin and a plurality of components to be arranged and respectively carrying out approximate description to obtain a three-dimensional approximate model, setting a phi function according to the three-dimensional approximate model and calculating a non-interference constraint, setting a centroid error constraint and a safety distance constraint, calculating the rotational inertia of the spacecraft, carrying out finite element analysis on the structure of the spacecraft, setting a characteristic equation and solving the characteristic equation to obtain the vibration frequency of the spacecraft, and taking the rotational inertia and the vibration frequency of the spacecraft as optimization targets. And constructing a spacecraft component layout double-target optimization model by taking the non-interference constraint, the centroid error constraint and the safe distance constraint as constraint terms, and performing optimization solution on the spacecraft component layout double-target optimization model to obtain a spacecraft component layout optimization scheme meeting constraint conditions. According to the method, the spacecraft component layout optimization problem considering the quality characteristic and the vibration frequency characteristic at the same time can be efficiently and accurately processed.

The invention discloses a critical parameter prediction method for a vertical cantilever fluid conveying pipe comprising a water injection pump and a Y-shaped nozzle, and relates to the field of fluid conveying pipe critical parameter calculation. The prediction method is based on an Euler-Bernoulli beam model and a momentum theorem, bending force, centrifugal force, Coriolis force, inertia force, gravity and additional force generated by an elbow are comprehensively considered, and an oscillatory differential equation of the fluid conveying pipe is established. The method comprises the following steps: performing dimensionless processing on an oscillatory differential equation by introducing dimensionless parameters, deducing a characteristic equation, a characteristic function and a characteristic value under a cantilever boundary condition, converting a partial differential equation into an ordinary differential equation set, and performing matrix solution; and finally, accurate prediction values of the critical flow velocity and the critical frequency can be obtained. The method can effectively reflect the influence rule of the nozzle and the concentrated mass on the vibration characteristics of the fluid conveying pipe, and realizes the accurate prediction of the critical parameters of the vertical cantilever containing the concentrated mass belt Y-shaped nozzle fluid conveying pipe.

The invention discloses a PID parameter setting method for suppressing conflict between primary frequency modulation and secondary frequency modulation of a hydroelectric generating set, and belongs to the technical field of hydroelectric generating set adjustment. Comprising the following steps: S1, calculating an initial value of a PID (Proportion Integration Differentiation) parameter according to a water diversion system water flow inertia time constant and a hydroelectric generating set mechanical inertia time constant; s2, taking the PID parameter initial value of the speed regulator as a PID parameter value, solving the root of the characteristic equation in the S1, and calculating a unit power dynamic analytical expression during frequency unit step disturbance according to a Fisher method of a quartic equation; s3, calculating an analytic expression of the hydroelectric generating set power square error integral quantity based on the unit power dynamic analytic expression; and S4, calculating a speed regulator PID parameter formula for suppressing the conflict between the primary frequency modulation and the secondary frequency modulation of the hydroelectric generating set according to the analytic expression of the unit power square error integral quantity and the initial value of the speed regulator PID parameter. The problem that the dynamic process of primary frequency modulation and the dynamic process of secondary frequency modulation conflict is solved, and the adjusting capacity of the hydroelectric generating set can be brought into full play.

The invention belongs to the technical field of power system stability analysis and control, and relates to a wind power plant characteristic root rapid solving method and system based on the circular ring theorem, and the method comprises the following steps: S1, carrying out the online identification of impedance; s2, constructing a wind power plant grid-connected system characteristic equation; s3, establishing a circular ring theorem model; s4, analyzing the stability of the wind power plant grid-connected system; according to the technical scheme, the calculation method of the circular ring theorem is adopted, the order number of the wind power plant grid-connected system does not need to be reduced, the feature root of the high-order wind power plant grid-connected system can be rapidly calculated, the solving efficiency is high, meanwhile, the directional capturing capacity of the main feature root is high, and the main feature root of the wind power plant grid-connected system can be rapidly searched.

The invention relates to an ultrasonic guided wave modal analysis method, device and equipment in a fluid saturated porous medium and a computer readable storage medium, and the method comprises the steps: determining a fluctuation control equation in a solid-fluid coupled porous medium domain; describing a conversion relation between the particle displacement of any position in the porous medium domain and the particle displacement of the corresponding section through a wave number and an angular frequency, and converting the fluctuation control equation in the solid-fluid coupled porous medium domain into a characteristic value solving form based on the conversion relation to obtain a characteristic equation; after specific boundary conditions are applied to the boundary of the porous medium, numerical solution is carried out on the characteristic equation; and according to a feature solving result, generating a modal analysis result of the ultrasonic guided wave. The technical scheme disclosed by the invention is particularly suitable for modal analysis of ultrasonic guided waves in a fluid saturated porous medium with an irregular section.

The invention relates to the technical field of ultrasonic guided wave nondestructive testing, and particularly discloses an arched concrete filled steel tube bridge detection method based on ultrasonic guided wave frequency dispersion characteristics, which adopts a theoretical derivation-simulation verification-experimental analysis method, and comprises the following steps: firstly, establishing a fluctuation characteristic equation based on a rotating coordinate system and a semi-analytical finite element method; deriving a guided wave frequency dispersion equation, obtaining a frequency dispersion curve through numerical calculation, and determining an optimal monitoring mode and an excitation frequency range; a three-dimensional finite element model is constructed for wave field numerical simulation, and the reliability of the model is verified through comparison of a theoretical solution and a simulation solution; then carrying out an ultrasonic guided wave detection experiment, collecting a time domain signal and extracting an actually measured frequency dispersion characteristic; and finally establishing theoretical prediction through time-frequency analysis, comparing numerical simulation with experimental data, and verifying the accuracy of a theoretical model in combination with error analysis. The method can accurately detect the defects of the arched concrete-filled steel tube bridge, and improves the reliability and practicability of complex structure damage identification.

The invention discloses a dynamic interaction and instability risk analysis method between energy storage modules of an energy storage power station, and the method comprises the steps: firstly building a linearization model of an energy storage integrated system, and recognizing the interconnection relation among the energy storage modules, an AC network and an external power system; a transfer function of an energy storage module is derived under a d-q coordinate system, a closed-loop transfer function model is constructed, a characteristic equation is extracted, and oscillation modes and stability of the energy storage module under different control strategies are analyzed. Research finds that the system stability is influenced by factors such as power amplitude, line parameters and control parameters, and an optimization design scheme is proposed to improve the system stability. In addition, the method also considers the risk of subsynchronous oscillation, and provides a theoretical basis and practical guidance for a safe and efficient energy storage integrated system. The method promotes the application of the energy storage technology in the power system, and enhances the performance and reliability of the system.

The invention discloses a photovoltaic power generation capacity credibility evaluation method based on joint probability modeling and a random process, and the method comprises the steps: collecting historical irradiance and temperature data of a target region, extracting an hour-level mean value and a standard deviation of the historical irradiance and temperature data, and dividing a seasonal data set; a Copula function is adopted to construct a joint probability distribution model of irradiance and temperature, a Gumbel Copula function is selected in summer, and a Clayton Copula function is selected in winter; generating a random fluctuation sequence of irradiance and temperature based on a stochastic differential equation, and calculating photovoltaic real-time output by combining a photovoltaic cell characteristic equation; a double-state Markov model is adopted to simulate traditional unit faults and load fluctuation, and system loss of load expectation (LOLE) is quantified through Monte Carlo simulation; carrying out dynamic iteration by utilizing an equivalent conventional capacity method (ECP), and calculating the capacity credibility of photovoltaic power generation; according to the invention, a reliability evaluation basis is provided for high-proportion photovoltaic grid-connected planning.

The invention provides a method and a system for designing a fractional order [PI] controller of an inertia and delay fractional order object. The method comprises the following steps of: describing a controlled object by adopting an inertia and delay fractional order transfer function; selecting a fractional order [PI] controller as a feedback controller; the closed-loop system is composed of a controlled object and a fractional order [PI] controller. Obtaining a characteristic equation of a closed-loop system; traversing the order and frequency of the controller, solving to obtain a complex root stability domain, and combining with a real root stability domain to obtain a fractional order [PI] controller stability domain; the proportional gain, the integral gain and the order of the controller are uniquely solved based on three constraint equations of a given crossing frequency, a phase margin and a condition that the slope of an open-loop phase of a closed-loop system at the crossing frequency is zero (also known as phase flatness); if no solution exists, the crossing frequency and the phase margin are given again for solution. The fractional order [PI] controller obtained through the method has high robustness and has practical application value.

The application relates to the field of circuit state space equation solving technology in the real-time simulation field, and discloses a state space equation discretization method for capacitor and inductor element characteristics, which comprises the following steps: A) establishing a state space differential equation of a circuit; B) establishing a characteristic equation of a capacitor and an inductor element, determining a numerical integration method used by each capacitor and inductor element in the circuit, and obtaining a discrete time domain characteristic equation by using the numerical integration method; C) combining the discrete time domain characteristic equation of step B) and the state space differential equation of step A) to obtain a state space discrete equation of the circuit; and D) cyclic simulation. The state space equation discretization method for capacitor and inductor element characteristics improves the speed and precision of real-time simulation of a circuit system by independently discretizing the characteristic equations of each capacitor and inductor element and optimizing the discretization process of the state space equation.

The invention discloses a capacity configuration method and system for a reactive power compensation device of a multi-machine system. According to the method, a synchronous machine electromagnetic power phase angle characteristic curve equation and a synchronous machine mechanical power phase angle characteristic equation before a fault of the multi-machine system and after the fault is removed are jointly constructed through parameters of all elements in the multi-machine system configured with the reactive power compensation device, and power angle values before and after the fault of the synchronous machine are calculated according to the equation; the capacity demand value of the reactive power compensation device configured by the collection bus in the multi-machine system is calculated by using an area method according to the constructed equation and the power angle value of the synchronous machine, so that the rationality of the capacity of the reactive power compensation device configured by the multi-machine system is improved, and the probability of transient power angle instability transmission of the synchronous machine of the multi-machine system is further reduced. The problem that in the prior art, due to the fact that the capacity of a configured reactive power compensation device is unreasonable and cannot adapt to faults of a multi-machine system, transient state power angle instability occurs when the multi-machine system breaks down is solved.

This invention discloses a quantitative analysis method for the DC-side stability of a grid-connected direct-drive wind turbine, belonging to the field of wind turbine power generation technology. The method includes: establishing a DC-side impedance model of the grid-connected direct-drive wind turbine corresponding to the turbine-side converter, grid-side converter, and DC capacitor; performing an equivalent transformation on the DC-side impedance model to establish a characteristic equation for measuring the DC-side stability of the grid-connected direct-drive wind turbine, thereby obtaining a quantitative index for measuring the DC-side stability of the grid-connected direct-drive wind turbine; and judging the DC-side stability of the grid-connected direct-drive wind turbine based on the comparison result of the proposed quantitative index ζ and a reference threshold. This method overcomes the problem that existing stability studies on grid-connected direct-drive wind turbines only focus on the interaction between the turbine and the grid, without considering the interaction between the turbine-side converter and the grid-side converter, resulting in inaccurate stability analysis results.

The invention relates to the technical field of electromagnetism, in particular to a multi-layer slab waveguide mode processing method, device, equipment, medium and program, and the method comprises the steps: constructing a transfer matrix model of a multi-layer slab waveguide; obtaining boundary conditions of the infinite space, and determining a corresponding real number domain characteristic equation and a complex number domain characteristic equation according to the transfer matrix model and the boundary conditions so as to determine a guided mode and a leakage mode of the multilayer slab waveguide in the infinite space; introducing a perfect matching layer to convert a radiation condition of an infinite space into an absorption boundary in a finite computational domain, constructing a finite space characteristic equation according to the thicknesses of the perfect matching layer and the absorption boundary, and positioning a plurality of correction leakage modes according to the finite space characteristic equation to generate a Bereger mode; and generating complete mode distribution according to the guided mode, the leakage mode and the Bereger mode. Therefore, the problems of relatively poor calculation precision, relatively slow calculation speed, limitation of complete mode solving in the multilayer slab waveguide and the like in related technologies are solved.

The invention discloses an electric vehicle experiment table mechanical inertia compensation method for high-precision dynamic simulation. According to the method, an expansion state observer is introduced into an inertia compensator to replace a traditional differential link, system total disturbance including acceleration dynamics and unmodeled dynamics is expanded into new state variables for unified observation and compensation, and the problem that the rotation speed simulation precision is reduced due to high-frequency noise amplification of an experiment table under high-multiple compensation is solved; constructing a system closed-loop discrete mathematical model containing ESO, and determining a stability boundary of the system under high-multiple compensation by using a characteristic equation of the system closed-loop discrete mathematical model and a Jure criterion; a sparrow search algorithm with a working condition adaptive boundary early warning mechanism is adopted in a stable domain to optimize observer gain, and the conflict between the low-speed and high-precision requirement and the high-speed and high-robustness requirement is solved. According to the invention, the interference of high-frequency noise on a compensation loop is effectively solved, and high-precision and high-stability simulation of the mechanical dynamic state of the large-inertia electric vehicle under all working conditions is realized.

The invention discloses a spacecraft system disturbance estimation method with random suppression intensity of measured noise, which belongs to the technical field of disturbance estimation of spacecraft systems, and comprises the following steps of: 1, establishing a nonlinear model of a spacecraft system considering the measured noise, and accurately representing the dynamic behavior of a spacecraft in a complex environment by using the model; 2, a variable-order filter with independent parameters is established, the designed filter has the same cascade structure as the observer, and therefore the parameters of the filter and the observer are mutually independent and not coupled; and step 3, aiming at an observer parameter adjustment problem, adopting an undetermined coefficient method, solving a proposed ESO characteristic equation of filtering and a characteristic equation of an expected configured pole, carrying out coefficient comparison on the two equations, and determining an observer parameter. According to the method, the parameters of the filter are increased along with the increase of the order of the filter, and the sum of the parameters of the observer is equal to the order of the observer, so that the problem of excessive parameterization is avoided, and arbitrary pole assignment is realized.

The invention discloses a parameter estimation and adaptive control method, device, medium and product of a high-performance aircraft pitch angular velocity control system with stability margin self-configuration, and relates to the field of aircraft control, the method comprises the following steps: collecting the pitch angular velocity of an aircraft and the deflection angle of an elevator in real time, and calculating a tracking error; constructing a relation equation of system parameters and stability margin based on a PI controller, and performing approximate simplification by adopting a numerical approximation method; estimating system parameters and time delay on line by adopting an approximate nonlinear least square algorithm; and substituting the target stability margin, the system parameter estimation value and the time delay estimation value into a system frequency domain characteristic equation for solving to obtain a proportional gain and an integral time constant of a PI controller, and adjusting an elevator deflection angle of the aircraft in combination with a tracking error so as to control the pitch angular velocity of the aircraft. According to the invention, the autonomous configuration of the stability margin is realized, and the stability, robustness and dynamic adaptation capability of the control system are improved.

The invention provides a vibration modal analysis method for a large-span cable-stayed bridge, and belongs to the technical field of bridge engineering, the cable-stayed bridge is simplified into a multi-cable cable-stayed beam structure considering the influence of cable force, and a cable-stayed bridge dynamic model is constructed through a parameterized order reduction technology; deducing a frequency characteristic equation of the cable-stayed bridge by combining a transfer matrix method and boundary conditions of the cable-stayed bridge; by solving the characteristic equation, the inherent frequency and modal characteristics can be determined more accurately and quickly; according to the method, the technical bottleneck of insufficient calculation efficiency of a traditional finite element method is innovatively solved, and fine evaluation of the fundamental frequency and the dynamic characteristics of the large-span cable-stayed bridge is completed; the method has both theoretical preciseness and engineering practicability, the calculation efficiency is remarkably improved, a new technical means is provided for dynamic performance evaluation of the kilometer-scale cable-stayed bridge, and the method has important engineering application value.

The application provides a control method and a control system of a steer-by-wire system. The method comprises the following steps: constructing a steering system dynamics equation based on a target front wheel running parameter, a configuration parameter and a target damping coefficient of a magneto-rheological damper in a shimmy instability mode, wherein the product of the target damping coefficient and a front wheel rotation speed is equal to the product of an initial damping coefficient of the magneto-rheological damper and a magneto-rheological damper current; obtaining a characteristic equation and all characteristic value expressions based on the steering system dynamics equation; obtaining real-time values of the target front wheel running parameter, a value of the configuration parameter, a magneto-rheological damper current real-time value and a value of the initial damping coefficient; obtaining real part values of all characteristic values of the characteristic value expressions based on the obtained values; and adjusting the magneto-rheological damper current real-time value until the real part values of all characteristic values are not greater than zero to obtain a value of the target damping coefficient, if there is at least one characteristic value whose real part value is greater than zero. The method according to the application can solve the front wheel shimmy problem.