51 results about "Eulerian lagrangian" patented technology

The invention discloses a fluid simulation method based on the Eulerian-Lagrangian coupling method. According to the aim of achieving efficient fluid simulation and the core idea of solving the N-S equation through the Eulerian method and the Lagrangian method to carry out fluid simulation, research is conducted through the multi-method coupling calculation method on the basis of SPH and LBM fluid simulation. Firstly, large-scale fluid field modeling is carried out through the LBM method based on Eulerian grids to build the main part of fluid simulation; then, simulation is carried out on fluid details such as spindrifts and water drops through the SPH method based on the Lagrangian particle idea, LBM fluid and SPH fluid are integrated by designing a coupling algorithm, and lifelike and rapid large-scale fluid simulation with details involved is achieved.

A computer system and method for performing a finite element analysis to determine the final dimensions of an object comprising automatically switching from an Eulerian formulation to a Lagrangian formulation during the analysis.

The invention provides a passive quasi-PR control method for a photovoltaic grid-connected inverter under a weak power grid, and belongs to the technical field of photovoltaic grid-connected invertercontrol. The method comprises the following steps: constructing a state average model according to a weak power grid single-phase full-bridge inverter equivalent topological graph in combination withthe Kirchhoff law, and then deriving an Euler-Lagrange mathematical model of a single-phase grid-connected inverter; establishing an energy function of the inverter system, analyzing an energy relationship existing in the inverter system, and then performing passivity analysis on the system to prove passivity of the inverter system; establishing an error energy storage function of the inverter system, and determining the change rate of an error energy storage equation of the inverter system by analyzing the change rate of the error energy storage equation of the inverter system; effectively changing the change rate of the error energy storage equation of the inverter system by adding a damping strategy, and shortening the time for reducing to zero; and firsty sending the error variable inthe error energy storage function to the quasi-PR controller to be processed and then sending the processed error variable to the traditional passive controller to obtain a passive quasi-PR control strategy.

The invention discloses a cooperative control method and system for escort tasks based on obstacle environment and bounded input. The method comprises the steps of describing a physical model of a escort task by adopting a multi-Euler-Lagrange system; using an inner and outer loop control structure, an outer loop adopting a behavior control method based on empty space, and generating expected speed and expected motion trails required by an inner loop physical model; an inner ring being based on an improved proportional derivative sliding mode control method of an adaptive radial basis functionneural network, so that each physical model can track an expected speed and an expected motion trail in the presence of interference and uncertain parameters, and zero steady-state error and boundedinput are realized. The controller provided by the invention has the advantages of simplicity, no model and capability of providing continuous control signals, and the adaptive radial basis function neural network adopted in the design of the controller has strong learning ability and robustness, so that interference is well compensated, and zero steady-state error is finally realized.

The invention discloses an unmanned ship model-free control method based on dynamic event triggering, and belongs to the technical field of unmanned ship control, and the method specifically comprises the steps: building a USV kinematics and dynamics model, and converting the USV kinematics and dynamics model into an Euler-Lagrange equation; a control law and an adaptive law are designed by utilizing sliding mode variable structure control and an Euler-Lagrange equation so as to construct a dynamic event trigger controller, and a control instruction of the trigger mechanism is updated only when a trigger condition is met; and defining a Lyapunov candidate function to carry out stability analysis on the dynamic event trigger controller, and simultaneously proving that no Zeno phenomenon exists. According to the method, the dependence of a traditional controller on a system model is overcome, the robustness of the system is improved, meanwhile, frequent controller signal updating is avoided, and the calculation cost, the executing mechanism loss and the energy consumption are remarkably reduced.

The invention relates to a mechanical arm tactile external force estimation method based on a mechanism data hybrid model, which comprises the following steps of: in a non-contact external force state, establishing a mechanical arm Euler-Lagrange rigid body dynamic model, and taking a difference between an actual joint torque and a mechanism model calculation torque as an unmodeled residual dynamic state; measuring and establishing a data set containing a joint state and an unmodeled residual dynamic state; training an unmodeled residual dynamic model compensation item based on the data set by using a supervised statistical learning method of Gaussian process regression to obtain a mechanism data hybrid model containing a mechanism model and the compensation item; joint external force is modeled and serves as pseudo observed quantity for dimension expansion, and a mechanical arm external force estimation model is established; and designing an external force estimation method with process noise variance updated along with the joint state. According to the method, mechanical arm tactile external force estimation with unknown coupling and unmodeled dynamics is achieved, and the method is suitable for a multi-scene multi-type force interactive mechanical arm system needing high-precision external force estimation.

The invention provides a subway people flow counting method based on scene flow, and belongs to the field of computer vision. The method includes: using RGB and TOF sensors to obtain RGB and depth image sequences when passengers get on and get off the bus; establishing a data item and introducing a smooth item, and constructing a scene flow energy functional; establishing an Euler-Lagrange equation to solve a scene flow; taking the calculated scene flow as a feature, performing moving target detection by adopting an ISODATA clustering analysis algorithm, and extracting a moving region; carrying out passenger head extraction in the motion area according to the passenger head features; achieving passenger target tracking according to the passenger head positions and the scene flow information detected by two adjacent frames; setting two detection lines in the image, judging get-on and get-off behaviors of the passenger if the passenger target passes through the detection lines in the tracking process, and updating a counting result; counting the number of passengers getting on and off the train at the stop according to the counting result of each train door, and obtaining the numberof passengers currently carried by the train.

The invention discloses a method for automatically identifying a diesel spray crushing process and automatically realizing the spray continuous calculation. The method automatically judges the processthat a liquid film is crushed into liquid drops in the diesel injection process, and realizes a SD-ELSA algorithm of the spray continuous calculation. The SD-ELSA algorithm is characterized in that the sphericity degree and the average particle diameter of liquid phases in grids are calculated and taken as judgment bases, the information of particles in a flow field are calculated through a Lagrangian method, the information of the grids belonging to continuous liquid phases in the grid node information in the full-flow field is calculated by using an Euler model, and Euler block masses meeting two bases for determination are converted into particles and re-calculated through the Lagrangian method. According to the method, dynamic converting coupling of the Euler-Lagrangian model is realized, the complete information of discrete phases and continuous phases in the flow field can be automatically obtained and subjected to iterative computation, three stages of a liquid column, primarycrushing and secondary crushing of the diesel injection are obtained, and the diesel spray process is completely represented.

The invention discloses a bubble plume turbulence closing method in the technical field of fluid engineering, and the method comprises the steps: deducing a source item related to bubbless in a turbulence transportation equation from a control equation of bubble plume based on gas-liquid two-phase bidirectional force coupling, and carrying out the modeling; constructing a free interface turbulencemodel, and deriving a source item of the influence of a free interface on turbulence; constructing a new turbulence model based on a standard k-epsilon turbulence equation, a source item related to bubbles in the turbulence transportation equation and a source item of the influence of the free interface on turbulence; adopting a CFD model of Euler-Lagrange-free interface tracking to simulate bubble plume, and combining a physical experiment to verify the new turbulence model. The new turbulence model provided by the invention can more accurately simulate a flow field and turbulence of the liquid phase, the distribution of the gas phase, the gas-liquid momentum transfer and the like, so that the dynamic characteristics and motion rules of the bubble plume can be more deeply studied.

The invention provides a simulation calculation method and system for transient synchronous unfolding of an aircraft folding rudder. The simulation calculation method comprises the following steps that hydrodynamic software and finite element software are applied to calculate an aerodynamic equivalent load borne by the aircraft at the initial unfolding moment of the folding rudder surface in the actual flight process; hydrodynamics and finite element software are applied to calculate the aerodynamic equivalent load borne by the aircraft in the unfolding process of the folding control surface in the actual flight process; the method also includes describing high-temperature and high-pressure gas generated after the explosive explodes by adopting a state equation, and simulating fluid-solid coupling interaction in real time through any Euler-Lagrange method; selecting and arranging the initial configuration and the initial orientation of the damping lug; and selecting the initial closed container volume and explosive equivalent of the folded rudder based on a simple model calculation result. According to the invention, high-temperature and high-pressure gas generated by explosion of the explosive is used as an expansion energy source, a simple model verification test and a fluid-solid coupling calculation method are adopted, the design efficiency is effectively improved, and repeated iteration in the design process is reduced.

The invention relates to a migration path analysis method for steam bubbles generated by a lead-based reactor accident. The method comprises the steps that 1, carrying out modeling according to reactor structure parameters, and inputting a primary loop initial temperature field, pressure field distribution, secondary loop temperature and pressure boundary conditions to serve as steady-state calculation initial values; 2, invoking a lead-based alloy physical relation, introducing a porous medium model and a turbulence Prandt model, and obtaining a steady-state temperature field and a pressure field of a primary loop of the reactor as initial values of accident condition calculation; 3, invoking a steam bubble drag force calculation function, and selecting a drag coefficient relational expression to calculate the drag force borne by the steam bubble; 4, invoking a relation of the quantity of the steam bubbles along with size distribution, and inputting a steam bubble quantity distribution rule at the initial moment of an accident; and 5, setting a crevasse position, and invoking an Euler-Lagrange algorithm to solve a steam bubble migration path until the path calculation is convergedand the migration duration meets the calculation requirement. The evaluation and guidance are provided for the design safety of the lead-based reactor and the judgment of the influence degree of thefracture accident of the steam generator heat transfer tube.

The invention discloses a space dust distribution rule analyzing method of an underground grain channel, and belongs to the technical field of dust distribution rule analyzing inside the grain channel. The technical purpose is to solve the problem that a dust prevention system inside the grain channel cannot be scientifically deployed and controlled since the dust distribution rule inside the underground grain channel cannot be effectively analyzed. The method comprises the steps of firstly, constructing a structure model of the underground grain channel, and selecting dust monitoring sites inthe structure model; conducting analog simulation on the dust flowing situation of the underground grain channel; putting up a test platform, and obtaining original monitoring data of the dust monitoring sites through a senor arranged on the test platform; adopting an Euler-lagrange algorithm to calculate the original monitoring data to obtain fluid flow transporting equations of a continuous phase and particle distribution data of a discrete phase; building a k-allele model according to the fluid flow transporting equations and the particle distribution data of the discrete phase, and calculating grain dust change distribution rule data relevant to temperature and humidity data. The space dust distribution rule analyzing method of the underground grain channel is used for analyzing the dust distribution rule.

The invention discloses a continuous cutting residual stress obtaining method and device and a storage medium. The method comprises the steps that a Lagrange model of a tool is established according to tool parameters of an actual tool; an Eulerian model of a workpiece is established according to workpiece processing parameters of an actual workpiece; grid division is performed on the Lagrange model and the Eulerian model; the Eulerian model and the Lagrange model are assembled according to the divided grids to obtain a coupled Eulerian-Lagrange model; and according to a preset machining condition, the coupled Eulerian-Lagrange model is utilized to simulate the process of cutting the workpiece by the tool so as to realize the extraction of the residual stress. The technical problem of large residual stress analysis errors in the prior art is solved.

The invention belongs to the technical field of coal mine underground fluid mechanics, and discloses an air flow-dust gas-solid two-phase flow numerical simulation method considering an environmental humidity factor, and the method comprises the steps: building a fully-mechanized face physical model according to a geological survey result; taking air flow and water vapor in air as a continuous phase, and describing fluid motion of the fully mechanized coal mining face by utilizing an Euler method; carrying out turbulence simulation by adopting a Reynolds time-averaging equation, solving by utilizing a k-epsilon equation, and expressing a transient pulsating quantity in the time-averaging equation; and establishing a mathematical model by using a component transport equation in the component transport model and an Euler-Lagrange equation in the dispersed phase model, and meanwhile, expressing the critical offset of particles in the collision process by using an O'Rourke formula due to the influence of a humidity field on the dust particles, so as to simulate the dust movement process in the fully mechanized coal mining face. The method provides a sufficient theoretical basis for researching the influence of the humidity field on the migration and diffusion of the dust in the coal mining process of the fully mechanized coal mining face.

The invention discloses a fan blade vibration reduction and parameter optimization method of an inerter-based dynamic vibration absorber, which comprises the following steps of: firstly, establishing a kinetic equation of a system consisting of a wind driven generator blade and the inerter-based dynamic vibration absorber by utilizing an Euler-Lagrange equation; further solving a transfer function from the external load borne by the wind driven generator blade to the displacement of the blade in the shimmy direction; secondly, carrying out dimensionless processing on the transfer function, and deducing an analytical expression of optimal structural parameters of the inertial-capacity-based dynamic vibration absorber by utilizing a pole assignment method; according to the method, the dynamic vibration absorber based on the inerter is applied to shimmy control of the blades of the wind driven generator, the analytical expression of the optimal parameters is given, and compared with a traditional method for solving the optimal parameters through numerical optimization, the optimal parameter expression in the analytical form obviously has better simplicity and universality.

The invention belongs to the field of insulation design and numerical simulation of high-voltage switch equipment, and particularly relates to a three-dimensional multi-field coupling simulation method for flow characteristics of multiple metal particles in GIS equipment. An Euler-Lagrange model and geometric modeling of particle flow under a coaxial cylindrical structure electric field are completed by writing open source codes of a CFDEM, and meanwhile numerical coupling of FVM and DEM algorithms is achieved. Calculation is completed on the basis of comprehensively considering a series of interactions of collision between particles, between particles and fluid, between particles and an electric field and between particles and an electrode and a shell and physical processes of charge and charge transfer when the particles collide with the electrode or between the particles, and characteristic parameters of particle flow characteristicssuch as the electric quantity, the speed, the displacement and the received acting force, are obtained. the dynamic distribution of multiple particles under two voltages of direct current and alternating current and the rolling state of the linear particles are finally observed through the post-treatment of the combination of the number and the shape, .

The invention discloses a water entry impact load modeling method for a cross-medium aircraft, and relates to the technical field of cross-medium aircrafts, and the method comprises the following steps: S1, employing CATIA three-dimensional model software to establish a geometric model of a cross-medium aircraft structure or assembly; s2, importing the geometric model into ABAQUS software, and establishing a liquid model in the ABAQUS software; s3, setting a water entry speed, an attack angle and an attitude, and solving in ABAQUS Solver by adopting a coupled Euler-Lagrangian method; s4, obtaining water entry impact load training data, and generating a training data file; s5, establishing a GRNN grid, and importing training data; and S6, obtaining the GRNN network model of the water impact load according to the S5, and rapidly estimating the load conditions in other states through the GRNN network model of the water impact load. Compared with a method in the prior art, the method has the advantages of being easy to implement, high in universality, small in modeling workload and high in calculation speed, and is suitable for rapid load evaluation calculation in the scheme design and engineering development process.

The invention discloses a self-adaptive control method based on a characteristic model. The method is characterized by firstly, acquiring the characteristic model of a controlled target; then, designing a coefficient of the characteristic model, a boundary related to a state and a parameter identification projection method; and identifying unknown coefficient variables in the characteristic modelby using a projection identification algorithm to obtain an identification value; and finally obtaining a control quantity according to the identification value so as to obtain input of the controlledtarget in a next period and complete closed-loop control based on the characteristic model in a current period. In the method, through designing the boundary of the coefficient related to the state and further designing the parameter identification projection method, a problem that the boundary of a constant is difficult to determine through the parameter of the characteristic model is solved, and adaptive control of a Euler-Lagrange system based on the characteristic model is realized. Meanwhile, the method can cover the multiple types of controlled targets, including Euler-Lagrange systemssuch as spacecraft controlled targets, advanced static var generator controlled targets and the like, and the method has good universality and an application prospect.

The invention relates to a posture self-balancing control method for a single-ball balancing robot, which comprises the following steps of: establishing a dynamic model by adopting an Euler-Lagrange equation method, constructing a dynamic differential equation set, and obtaining a relationship between an input torque and a posture; according to a modern control theory method, the controllability and observability of a robot system are pre-analyzed, a lead correction series network is designed, and posture self-balance control over the single-ball balance robot is achieved. According to the method, the problem that parameters cannot be measured is solved, the workload is reduced, and the practical engineering application range is expanded.

The invention relates to a constrained three-degree-of-freedom mechanical arm dynamic model, which is characterized in that the mechanical arm dynamic model is established by using an Euler-Lagrange method, a dynamic equation expression form of a state space of the mechanical arm dynamic model is given, and a motion plan of the mechanical arm dynamic model is calculated based on a particle swarm algorithm. The method has a quick response capability; accurate position deviation can be obtained; the control method has relatively high robustness and self-adaptability; the speed regulation range and the torque output range are large enough.