89 results about "Euler method" patented technology

The invention discloses an industrial robot torque compensation control method based on load adaptive identification. The industrial robot torque compensation control method comprises the steps that according to robot overall stress balance analysis, a robot dynamics model under the load working condition is established in a deduced mode through a Newton-Euler method on the basis of considering friction; the optimal excitation trajectory of robot load identification is solved; load inertial parameters are calculated; and on the basis of load inertia matching, joint driving torque consumed by the load when a robot moves under the load working condition is compensated, and further verification and optimization are conducted through experiments. According to the industrial robot torque compensation control method, the influences of the load on operation performance of the robot are considered, under the premise that no any external sensor is needed, adaptive identification of any load andtorque compensation control are completed through easy operation easy to achieve, the control precision of the robot under the load working condition is effectively improved, and very important significance for processes such as carrying and friction stir welding of the industrial robot under high-speed and large-load movement is achieved.

The invention provides a quadruped robot biped support phase force hybrid force control method. The method comprises the steps of (S1) projecting the overall movement of a robot to a radial plane and a normal plane, (S2) establishing a control model, simplifying the movement of the robot along the radial plane as a plane seven-connection-rod model, and simplifying the movement along the normal plane as a linear inverted pendulum model, and simplifying the plane seven-connection-rod model as a plane virtual telescoping leg model, wherein the control target of the plane virtual telescoping leg model is a mass center height, a body pitch angle and a horizontal displacement, (S3) carrying out hybrid controlling according to a control model, establishing the kinetic equation of the plane virtual telescoping leg model and establishing the kinetic equation through a Newton-Euler method, controlling the mass center height and the body pitch angle through a position servo method, and using the double-ring control method of outer ring position and inner ring foot end force for the horizontal displacement of a virtual telescoping leg plane model. The method has the advantages of good control effect and the improvement of robot adaptability.

The invention belongs to the technical field of identifying synchronous generator parameters, and relates to a method for identifying the synchronous generator parameters by an improved evolution algorithm. Starting from an randomly-generated initial generator parameter group, optimal solution is searched through generation of an initial group, fitness calculation, recombination, mutation and selection, and stopping operation according to operating principles of struggle for existence and survival of the fittest by using actual measurement data in a power management unit (PMU) in a wide area measurement system (WAMS); and an improved evolution strategy algorithm of biomimicry is taken as optimizing theoretical basis, the decoupling of a direct axis and a quadrature axis of the synchronousgenerator and steady state and transient state are processed separately, an initial practicable parameter group is established through design parameters, and a differential equation of a higher orderis calculated by selecting a high-precision improved Euler method, so that the output variable set by the generator is solved, the optimizing process is realized through recombination, mutation and selection of the initial group, and the synchronous generator parameters are identified. The method is simple and has a reliable principle, and the correctness of the parameter identification is high.

The invention provides a method for improving the identification precision of kinetic parameters of a modularized robot joint, and the method comprises the steps: carrying out the kinetic modeling through a Newton-Euler method, and enabling an improved Fourier series motivation track to be applied to a device for improving the identification precision of the kinetic parameters of the modularized robot joint; collecting an angle value, an angular speed value and a moment value through a sensor unit; carrying out the differential operation through the angular speed measured by a tachometer, obtaining an angular acceleration value, and carrying out the preliminary processing of information; carrying out the parameter estimation, and substituting parameters into a kinetic equation for estimating the kinetic parameters. The method employs the multi-sensor fusion technology, achieves the direct real-time measurement of the angles of a joint end and a motor end through two absolute coders, and improves the safety of a device. The mode of direct measurement reduces the calculation burden of a control unit, thereby facilitating the implementation of the real-time control, solving problems of interference and error increase caused by the indirect measurement, and improves the parameter recognition precision.

The invention relates to a composite material mechanics property evaluation method based on three-dimensional microcosmic crystal whisker composition, and belongs to the field of composite material mechanics. According to the method, an Euler method and a Monte Carlo method are combined, and the mechanics property of reinforced composite materials can be pre-estimated based on a space random three-dimensional crystal whisker microcosmic configuration. The microstructure of crystal whiskers is comprehensively represented, the number of the crystal whiskers, the length of pins and the space random distribution status are fully considered, and the composite material mechanics property evaluation method has the advantages that crystal whisker unit generation efficiency is high, pre-estimated mechanics parameters are accurate, and the method is easy and convenient to use. Qualitative research can be provided for stiffness analysis and a stress distribution law of tetrapod-like crystal whisker reinforced polymers, and the method can be popularized and applied to the effective elastic property, mesomechanics analysis and microscopic damage failure numerical calculation of the randomly-distributed crystal whisker reinforced composite materials, and has obvious advantages compared with a two-dimensional method.

The invention discloses a physical and non-physical mixture-based complex scene fluid-solid coupling efficient simulation method. The method comprises the steps of 1) performing incompressible fluid simulation, combining an Euler method and a Lagrange method, and proposing an implicit particle method-based zero-divergence smooth particle fluid dynamics method; 2) performing dynamics problem solving in fluid-solid coupling, subdividing a motion problem of a simulation object into three sub-problems according to object attributes, and solving the three sub-problems by using different methods respectively to realize a multi-dimensional classification combination computing framework; and 3) combining a strain energy density concept in fracture mechanics with Voronoi spatial segmentation to realize a physical perception-based crushing method. The simulation efficiency problem difficult to solve in complex fluid-solid coupling scene simulation is solved. Compared with a conventional fluid-solid coupling method, the method can simulate a fluid scene with richer details under the same system resources, and can meet the demand of simulating solid crushing under fluid impact.

The invention relates to a method for controlling motion of a bionic long-fin undulatory propeller. The method comprises the following steps: aiming at different motion modes of the long-fin undulatory propeller, setting a corresponding control parameter and an initial value; iteratively solving a differential equation of a central pattern generator model by utilizing an Euler method according to the input control parameter and the initial value; calculating a swinging angle of each fin on the long-fin undulatory propeller by utilizing an output amplitude value of the central pattern generator model in the iterative calculation process; and converting the swinging angle into the control quantity of a steering engine for coordinating and controlling a plurality of steering engines on the long-fin undulatory propeller through a pulse width modulation wave generator to enable the long-fin undulatory propeller to generate undulatory motion with stable and continuous rhythm and realize forward, backward, emergent stop, turning and rapid startup. The method is simple, reliable and easy to realize, has small calculation quantity and can meet the real-time requirement of coordinating and controlling a plurality of circuits of the steering engines of the long-fine undulatory propeller.

The invention discloses a fabric deformation simulation method which, based on the classic spring-mass model, introduces the concept of a semi-rigid spline, and takes into full consideration of stretching property, compressing property, cutting property, bending property and surface roughness of the fabric, and effectively addresses the problem of anisotropy and superelasticity in fabric deformation simulation, and increases real sense of fabric deformation simulation. In aspect of numerical integration, compared with traditional explicit euler method and implicit euler method which have defects of slow solution speed, the method of the invention Verlet integration method which has substantial increase in velocity and computing stability. In aspect of collision treatment, the method further simplifies a collision model, and only considers collisions of "top pint-triangle" type and "edge-edge" type that occur in large amount in fabric simulation, which effectively reduces times for collision treatment and accelerates computing velocity.

The invention provides a double-rigid-body characteristic point saturation fixed time relative pose tracking control method. The method comprises the steps: establishing a pose kinetic equation of a tracker and a target device based on a Newton-Euler method; establishing a relative pose kinetic equation considering model uncertainty according to the established respective pose kinetic equations ofthe two rigid bodies and the relative pose and the relative speed between the two rigid body feature points; designing a fixed time disturbance observer according to the established relative pose kinetic equation; designing a non-linear saturation compensator according to the established fixed-time non-singular terminal sliding variable so as to solve the saturation effect of an actuator; and combining the established fixed-time disturbance observer and the nonlinear saturation compensator to obtain a model-based robust adaptive controller. The invention relates to the field of control of anautonomous moving body in a three-dimensional space and spacecrafts.

The invention discloses a power system transient stability simulation method based on explicit numerical integration, which is suitable for a generator to adopt a second order model, and overcomes the shortcomings of a conventional power system transient stability numerical integration method that the computing quantity is large and the computing speed can not meet the on-line computing requirement of a power system. Compared with the conventional power system transient stability numerical integration method, in the power system transient stability simulation method provided by the invention,the characteristic that analytical expression exists in a second derivative d<2>Delta/dt<2> of a power angle Delta is utilized to deduce the explicit second-order single-step integration formula of the motion equation of a generator rotor, which has the local truncation error of O(h<3>), and the computing quantity is equivalent to the explicit Euler method with the local truncation error of O (h<2>); and the characteristic that when the generator adopts the second order model to describe, only the power angle is required to be obtained during solving the network algebraic equation set is alsoutilized, and the differential-algebraic equation is only required to be solved at one time in each integration step. By adopting the invention, the speed of the transient stability simulation computation based on explicit numerical integration is remarkably increased, and the method is equivalent to half of the improved Euler method.

The invention discloses an arbitrary Lagrange Euler method based on the multi-dimensional Riemann solution. The method is used for solving two-dimensional compressible fluid mechanics equation sets and relevant issues based on the same. The arbitrary Lagrange Euler method based on the multi-dimensional Riemann solution includes: grid generation and physical quantity initial distribution; determination of a strategy and a manner of grids at a next moment; determination of a two-dimensional Riemann solution implement algorithm of grid cell frontier flux; expression form of the grid cell frontier flux; acquisition of a numerical method of a calculation result at the next moment. The novel two-dimensional Riemann solution implement algorithm for determining the grid cell frontier flux is provided, conditions such as proneness to distortion of grids, instability of numerical value impact waves and the like resulted from a traditional one-dimensional Riemann solution can be overcome, and the defect that an existing two-dimensional Riemann solution method is too complicated to implement is corrected. The arbitrary Lagrange Euler method based on the multi-dimensional Riemann solution is a simple, robust and precise numerical algorithm component, suitable for numerical simulation of multimedium large-deformation problems, and further suitable for currently popular forms of finite differences, finite volume and finite element methods.

The invention discloses an adaptive variable-step integration method for global energy Internet operating characteristic simulation. According to the method, influence factors of energy, politics and economy are extracted, rate variables and state variables are determined according to the causality between all the influence factors, a macroscopic operating characteristic causal graph of global energy Internet is established, historical data of the influence factors of different types is subjected to standardization processing, all the variables are selected in sequence, all variable sets pointing to the variables is searched for, an algebraic equation between the variables is determined according to the historical data, construction of a mathematical formula between system variables of the global energy Internet is completed, the equation is subjected to differencing processing, an improved Euler method is adopted to perform iteration before an emergency happens, a fourth-order Ronge-Kutta method is adopted to perform iteration after the emergency happens, simulation prediction is performed with an adaptive step, and macroscopic operating characteristics of the global energy Internet are predicted and deduced.

The invention discloses a quasi-steady state variable step simulation method applicable to a long time scale in a power system, belonging to the field of simulation technology of power systems. The method comprises the steps of firstly establishing a quasi-steady state simulation model of the system, performing load flow calculation on the power system to obtain a steady state value of each variable, and then selecting a numerical integration method according to the state of the system, wherein when the system is in a quick change phase, an improved Euler method of a fixed step is adopted for solving; and when the system is in a slow change phase, an implicit trapezoidal integration method of a variable step is adopted for solving. The method improves the quasi-steady state simulation speed of the power system, also improves the stability of the numerical algorithm, and overcomes the defects of the quasi-steady state simulation method for the long time scale in the power system.

This invention relates to, in order to numerically analyze contaminant transport in groundwater, a method of analyzing contaminant transport under Cauchy boundary conditions using an improved Lagrangian-Eulerian method, wherein problems of a conventional Lagrangian-Eulerian method able to analyze only high Peclet numbers are solved, and which is configured to analyze a new numerical matrix constructed in such a manner that a Eulerian method is applied to an element adjacent to Cauchy boundary conditions and a conventional Lagrangian-Eulerian method is applied to an internal element, thereby enabling accurate numerical analysis of contaminant transport at various Peclet numbers including not only high Peclet numbers but also particularly low Peclet numbers under Cauchy boundary conditions.

The invention discloses a method and a device for quickly determining permeability functions of unsaturated soil. The method comprises the following steps: carrying out discretization and inverse solving on a partial differential equation of a basic soil water movement equation Richards by applying a forward Euler method and a backward Euler method to obtain two permeability coefficient expressions of the unsaturated soil; then measuring a series of data that the volumetric water content theta t at detla z in a sample and tension ht change along the time through a constant water head one-dimensional vertical unsaturated infiltration test; substituting experimental data into obtained two expressions; combining calculation results of the two expressions to quickly and accurately obtain the permeability functions of the unsaturated soil. The experimental device comprises a sample cylinder body, a measuring system, a water supply system and a water collecting system; the water supply system is used for providing constant water head water source required by the test; the water collecting system is used for collecting and measuring water yield; the measuring system comprises a sensor for measuring the theta t and the tension ht and an automatic acquiring device for acquiring data; the sensor is buried at a fixed position delta z inside the sample cylinder.

The invention discloses a trajectory tracking control method for an unmanned autonomous vehicle. The trajectory tracking control method is specifically implemented according to the following steps: establishing a two-degree-of-freedom kinematics model of the unmanned autonomous vehicle; constructing a trajectory tracking controller based on nonlinear model predictive control, and adding a single-step Euler method into a predictive model of the controller; designing a constraint equation of the nonlinear model predictive controller, and establishing a target function based on the minimum difference value between the control trajectory output of the nonlinear model predictive controller and the reference trajectory; and solving the input of the unmanned autonomous vehicle according to the minimum objective function. A proposed nonlinear model predictive controller can track a reference trajectory more quickly, and has a smaller fluctuation error and a smoother trend in the tracking process. The control method provided by the invention can effectively improve the driving stability and safety of the vehicle, and has great significance for trajectory tracking control of the unmanned vehicle.