381 results about "Kinetics" patented technology

The invention discloses a control simulation method for a near-space hypersonic aircraft. The method comprises the following steps of: (1) establishing a motion model of the aircraft under the condition of a variable wind field; (2) establishing a motor power model of the near-space hypersonic aircraft; (3) establishing a pneumatic parameter base and an engine parameter base related with the motion model and the power model; (4) designing an attitude steady tracking control law and a centre-of-gravity motion control law on the basis of the motion model according to different task requirements; and (5) calculating atmosphere data and wind field data in the current state in real time, calculating all states of the aircraft according to the atmosphere data and wind field data and the designed control law, and repeating the steps until the simulation is finished. In the method, a whole set of the motion model of the near-space hypersonic aircraft under the condition of the variable wind field is provided on the basis of fully analyzing dynamic and kinematic laws of the near-space hypersonic aircraft and by combining the actual conditions of the motor power model and the atmospheric wind field environment. The invention also discloses an aircraft-based control simulation platform.

The invention provides a method for computational fluid dynamics and apparatuses making enable an efficient implementation and use of an enhanced jet-effect, either the Coanda-jet-effect, the hydrophobic jet-effect, or the waving-jet-effect, triggered by specifically shaped corpuses and tunnels. The method is based on the approaches of the kinetic theory of matter, thermodynamics, and continuum mechanics, providing generalized equations of fluid motion. The method is applicable for slow-flowing as well as fast-flowing real compressible-extendable fluids and enables optimal design of convergent-divergent nozzles, providing for the most efficient jet-thrust. The method can be applied to airfoil shape optimization for bodies flying separately and in a multi-stage cascaded sequence. The method enables apparatuses for electricity harvesting from the fluid heat-energy, providing a positive net-efficiency. The method enables efficient water-harvesting from air. The method enables generators for practical-expedient power harvesting using constructive interference of waves due to the waving jet-effect.

Computer simulation of the dynamics of rigid bodies interacting through collisions, stacks and joints is performed using a constraint-based system in which constraints are defined in terms of the positions of the bodies. Displacements caused by reaction forces necessary to ensure that the bodies comply with the position constraints can be calculated and can be done iteratively by updating equations defining the reaction forces and the displacements such that the computation time and memory resources required to perform the calculations is linearly dependent upon the number of bodies and the number of contacts and joints between the bodies.

Method for the estimation of at least a variable (β; νx, νy; ψ, μ) affecting a vehicle dynamics (10), including measuring dynamic variables (MQ) of the vehicle (10) during its motion, calculating in real time an estimate (Formula (I)) of said variable (β; νx, νy; ψ, μ), on the basis of said measured dynamic variables (MQ), The method includes: calculating (230) said estimate of said at least a variable (β; νx, νy; ψ, μ) by an estimation procedure (DVSβ; DVSβν; DVSβνμ) comprising taking in account a set of dynamic variables (MQ) measured during the motion of the vehicle (10) over respective time intervals (ny, nw, nψ, nx, nα) and applying on said set of measured dynamic variables (MQ) at least an optimal nonlinear regression function (ƒ*β; ƒ*x, ƒ*y; ƒ*β1, ƒ*β2, ƒ*ψ1, ƒψ2) calculated with respect to said variable (β; νx, νy; ψ, μ) to estimate to obtain said estimate of said variable (β; νx, νy; ψ, μ), said optimal non linear regression function (ƒ*β; ƒ*x, ƒ*y; ƒ*β1, ƒ*β2, ƒ*ψ1, ƒ*ψ2) being obtained by an optimal calculation procedure (220) including: on the basis of an acquired set of reference data (Dd) and of said set of dynamic variables (MQ) measured during the motion of the vehicle (10), finding, for a desired accuracy level (ε), a regression function (ƒ*β; ƒ*x, ƒ*y; ƒ*β1, ƒ*β2, ƒ*ψ1, ƒ*ψ2) giving an estimation error lower or equal than said desired accuracy level (ε) in a given set of operative conditions (OC), said acquired set of reference data (Dd) being obtained by acquiring (210) in said given set of operative conditions (OC) a set of reference data (Dd) of variables including variables corresponding to said measured dynamic variables (MQ) of the vehicle (10) and a lateral (vy) and a longitudinal velocity (vx) of the vehicle (10).

The invention provides an optimized anti-shake control method for a double-pendulum system of a bridge crane. The method comprises the steps that the running speeds of a cart and a trolley are calculated according to the load weight and the rope length measured in real time; based on the dynamic differential equation of the crane, an analytical solution of a single-pendulum model of the bridge crane is obtained; using a quadratic objective function of an analytic solution under the action of three pulses, an optimal input shaper with a zero initial state is calculated; and then, according to acascade method for solving a dual-mode input shaper, the optimal input shaper for the double-pendulum system of the bridge crane is designed, and the swing of the load is eliminated by driving a cartrunning mechanism and a trolley running mechanism through a cart frequency converter and a trolley frequency converter respectively, so that the optimal anti-shake control of the double-pendulum of the crane is realized. The optimized anti-shake of long load horizontal lifting is realized, and the working efficiency and operation safety of the bridge crane are improved, so that the running speedsand running tracks of the cart and the trolley are more reasonable, and the engineering application is facilitated.

The invention relates to a method and a device for determining a variable describing the speed (VwheelDef)of at least one driven wheel (1, 2, 3, 4) of a motor vehicle. In this context, variables describing the respective wheel speeds (Vwheeli)for the remaining driven wheels of the motor vehicle, and a variable describing the output rpm (noutput) of a transmission (5) of the motor vehicle are determined. To be able to make a reliable variable describing the speed magnitude of the wheel (1, 2, 3, 4) available to a traction control system or a vehicle-dynamics control system of a motor vehicle in spite of the failure of a speed sensor (9, 10, 11, 12) arranged at one of the wheels, it is proposed that the variable describing the speed (VwheelDef) for the at least one driven wheel (1, 2, 3, 4) be determined as a function of the variables which describe the respective wheel speeds (Vwheeli) of the remaining driven wheels and as a function of the variable which describes the transmission output rpm (noutput).

The invention relates to the technical field of mechanical manufacturing simulation experiment devices, and specifically relates to an adjustable multi-gap gear-connecting rod mechanism dynamics experiment simulation system. The system comprises a base. The system is characterized in that a gear rotor assembly and a crank sliding block assembly are arranged above the base, and the gear rotor assembly is composed of a driving gear, a driven gear, a driving motor and a driven gear fine adjustment platform. Front-back and left-right displacement of the driven gear is adjusted through the driven gear fine adjustment platform. Therefore, the gear backlash between the driven gear and the driving gear is adjusted. A slider-crank assembly is arranged on the side surface of the driven gear. The crank sliding block assembly is composed of a connecting rod, a sliding block and a gap adjusting sliding rail. The size of the sliding pair gap can be adjusted by adjusting the gap of the gap adjustingguide rail, and the beneficial effects are that the structure is simple, and the gear pair tooth side gap, the rotating pair radial gap and the sliding pair gap can be accurately adjusted at the sametime conveniently and rapidly are achieved.

Systems and methods for providing a mechanism of simulating fluid dynamics while maintaining the incompressibility of a fluid based on a position based dynamics (PBD) framework. A set of constraint equations that enforce constant density of the particles in a fluid object are formulated in terms of neighbor particle positions. The formulated constraint equations can be solved iteratively in a Jacobi method to obtain a new position and new velocity of each particle in large time steps. Voracity confinement may be introduced to simulate turbulent motions of the fluid object based on an unnormalized curl of the particle velocities. A positive artificial pressure term can be incorporated in particle position updates to reduce particle clustering or clumping effect caused by negative pressures related to neighbor deficiencies.

The invention provides an experiment device and method for measuring the turbulent friction resistance of a flat plate, and belongs to the technical field of aerodynamics testing. The experiment device comprises a smoke collecting chamber, an air channel, a test flat plate, a velocity collector, a guide rail, a sliding block and a stepper motor, and is characterized in that the air channel is formed by sequentially connecting an air collecting section, a stabilizing section, a contracting section, an experiment section, a diffusing section, a corner section, a power section and an outlet section, the smoke collecting chamber enables the air collecting section and the outlet section of the air channel to be communicated so as to form a set of complete air circulation system, the test flat plate is fixed at the center of the experiment section, the guide rail is arranged on the wall of the experiment section below the test flat plate, the guide rail is set in a mode of being parallel to the air flowing direction, and a laser probe of the velocity collector is fixed on the sliding block on the guide rail. The experiment device is simple in structure and simple and convenient to operate, directly measures an average velocity profile of the flat plate at different flowing direction positions, solves the friction velocity through fitting and calculates the wall friction stress and local resistance coefficient of a turbulent boundary layer of the flat plate.

The invention discloses a vehicle yaw stability prediction control method and system. The method comprises: determining an expected side slip angle of a vehicle, and determining the expected yaw velocity of the vehicle according to the longitudinal vehicle speed and the front wheel rotation angle fed back by the vehicle; according to the longitudinal vehicle speed, the expected yaw velocity and the expected side slip angle fed back by the vehicle, constructing a state updating equation in combination with a vehicle dynamics model and a tire magic formula, considering safety constraints of a side slip angle and a yaw velocity and an external yaw moment driving constraint, and constructing an NMPC optimization control problem by taking minimization of a vehicle state following error two-normas an optimization target; solving the NMPC optimization control problem by adopting an improved C / GMRES algorithm to obtain an optimal solution of the external yawing moment; and inputting the optimal solution of the external yawing moment into a wheel hub motor moment distribution module as an output moment reference. The method is high in calculation efficiency, and the problems that an initial solution of a traditional NMPC controller is difficult to obtain, and the optimality of the initial solution is difficult to guarantee are solved.

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 provides a joint animation modeling technology based on physics in a fluid environment. In order to improve real motion effect of a joint animation under the action of complex field force and to reduce operation expenses, the joint animation modeling technology in the fluid environment comprises the steps that modeling is carried out on drive, the dynamics and the stress effect of a hinge body, and a calculation process of the joint animation based on the forward dynamics in the fluid environment is formed. According to the data drive, due to the fact that an independently-invented controller based on factored moment is used, accuracy and stability of a tracking path are improved; according to the dynamics, due to the fact that the lagrangian dynamics is used for carrying out modeling, cost of variable calculation is reduced, and operation efficiency is improved; according to the external force action, external force of fluid to the hinge body is divided into external force in the normal direction and external force in the tangential direction, and solution is carried out on the external force in the normal direction and the external force in the tangential direction to obtain the more real stress effect. The joint animation modeling technology in the fluid environment can effectively achieve the joint animation which is on the basis of the physics and has the real motion effect.

The present invention relates to a method and system for describing the motion of a closed-loop multibody mechanism. In this case, equations of motion need to be obtained for constrained multibody systems. The invention is based on a forward dynamics formulation resulting in a recursive Hamiltonian formulation for closed-loop systems using generalised co-ordinates and conjugated canonical momenta. The method allows to limit the number of arithmetical operations necessary to obtain the equations of motion with a good evolution of the constraints violation errors. Calculations can be performed based on constrained articulated momentum vectors.

Computer simulation of the dynamics of rigid bodies interacting through collisions, stacks and joints is performed using a constraint-based system in which constraints are defined in terms of the positions of the bodies. Displacements caused by reaction forces necessary to ensure that the bodies comply with the position constraints can be calculated and can be done iteratively by updating equations defining the reaction forces and the displacements such that the computation time and memory resources required to perform the calculations is linearly dependent upon the number of bodies and the number of contacts and joints between the bodies.

The invention discloses a quick attitude maneuver method and system under the conditions of large interference and small inertia, and the method comprises the steps: (1), carrying out the quick estimation of an interference moment through combining with an attitude kinetic equation according to the control quantity of an upper beat and the angular speed collected by a current beat; (2) performingquaternion and angular velocity prediction by utilizing an attitude kinetic equation based on the estimated disturbance force moment and considering the control time delay; (3) calculating a quaternion error of the body attitude relative to the target attitude according to the target quaternion and the predicted body quaternion, and dividing the body attitude into a constant angular velocity control area, a parabola target angular velocity control area and an attitude angle control area according to the quaternion error; (4) based on quaternion partition and the predicted attitude quaternion and angular velocity, calculating the control quantity of PID controller + disturbance torque feedforward; and (5) sending the calculated control quantity to a pulse width modulator, and obtaining theair injection time of the corresponding engine. By adopting the method, rapid attitude maneuver of the small-inertia spacecraft can be realized in the presence of dry large disturbance and time delay.

A method and apparatus for determining a trajectory for a vehicle are disclosed, wherein, the method includes: identifying a starting position (p0) and a desired terminal position (P) for the vehicle; linearly approximating dynamics of the vehicle; and using the starting position (p0), desired terminal position (P), and linear approximation, determining the trajectory for the vehicle. The linear approximation can be constrained by requirements (e.g., specifications) that: (i) an acceleration applied to the vehicle at a point on the trajectory is relatively large when the acceleration acts in a direction that is substantially perpendicular to the velocity of the vehicle; and (ii) an acceleration applied to the vehicle at a point on the trajectory is relatively small when the acceleration acts in a direction that is substantially parallel to the velocity of the vehicle. The vehicle may have a curvature limit.

The invention discloses an intelligent vehicle real-time trajectory planning method based on nonlinear model predictive control; the method comprises the following steps of by combining a linear two-degree-of-freedom model of a vehicle and a kinematic equation of the vehicle under geodetic coordinates, establishing a nonlinear dynamics equation of a controlled object; discretizing the establishednonlinear dynamics model by using a time interval Ts to obtain a state prediction equation of the system in the prediction time domain; constructing NMPC problem containing a terminal constraint by introducing a cost function and the constraint of the control problem; solving the nonlinear optimal control problem through a tool box, and obtaining the optimal control sequence, and supplying the first component of the optimal control sequence to the controlled object; and establishing a Simulink and Carsim combined simulation platform for experimental verification.

The invention discloses a circular pipe sideward swing impact device and a test method of the circular pipe sideward swing impact device, particularly relates to a testing system of a dynamic test for using a swinging circular pipe to impact on a circular pipe in different angles, and belongs to the field of kinetics experiment devices. The circular pipe sideward swing impact device comprises a driving pipe, a driven pipe, supporting devices, a loading device and measuring devices, wherein the fixed position of a supporting base is controlled to adjust the swing distance of a pipeline and the span of the driven pipe, the swing direction is controlled through a rotating platform, a gear device is driven by a motor to lift the driving pipe up, adjustment of the lifting angle and release of the driving pipe are conducted through an altitude angle rotating disk, and impact results are recorded through the measuring devices, so that experimental observation of sideward swing of the pipeline is achieved.

In a load weighing method for a wheel loader, an inclined angle of a ground surface on a slope where the wheel loader is working is detected. A change in a boom angle and a change in a pressure of a boom cylinder are detected while pivoting the boom and an attachment connected to the boom, wherein a load is placed on the attachment. Weight of the load is calculated using the inclined angle of the ground surface, the change in the boom angle and the change in the pressure of the boom cylinder as variables of a rotational dynamic equation for the pivot of the boom.

The invention provides a vortex-induced vibration simulation method for an elastic support rigid cylinder structure under the action of a nonlinear energy trap in the field of computational fluid mechanics numerical simulation. The vortex-induced vibration simulation method comprises the following steps: firstly, establishing a two-dimensional drainage basin and a geometric model of the two-degree-of-freedom elastic support rigid cylinder structure; secondly, respectively carrying out grid division on the two-dimensional drainage basin and the structural domain, and carrying out interpolationon the two sets of grids by utilizing a nested grid technology to form a flow field calculation grid; establishing a computational structural mechanics model under the action of the NES, combining thecomputational structural mechanics model with the computational fluid mechanics model, and performing cylinder fluid-solid coupling numerical calculation; and finally, carrying out post-treatment toobtain the vortex-induced vibration characteristic of the cylinder structure under the action of the NES and the inhibition effect of the NES on the vortex-induced vibration of the cylinder structure.According to the method, the vortex-induced vibration high-fidelity simulation model of the two-dimensional cylinder structure under the action of the NES is established on the basis of a computational fluid mechanics method, a structural dynamics theory and a nested grid technology, a numerical prediction result has high credibility, and reference is provided for researching cylinder vibration reduction.

Device for measuring the relative speed of movement of a fluid in relation to an object, characterised in that said device comprises at least one sensor 2 positioned in a suitable area of the object, wherein said at least one sensor 2 is capable of identifying and utilising, in conjunction with at least one computer 3, local aerodynamic or hydrodynamic instability, originating from the relative movement of said fluid in relation to an element 1 of said object, depending on the speed of movement of the fluid. The device is characterised in that said element 1 is an obstacle or a hollow cavity with a single opening contained in a body 40 and open towards the outside of said body, wherein said body is positioned on the object, the relative velocity of the fluid of which one wishes to ascertain, such that said cavity 1 is skimmed by the fluid and in that said at least one aerodynamic / hydrodynamic instability sensor 2 utilises the process of self-oscillation of the fluid inside the cavity 1 in order to determine the fluid's relative speed of movement.

The invention provides an electro-hydraulic servo system self-adaptive control method based on an expansion disturbance observer, and the method comprises the following steps: firstly building a mathematic model of the electro-hydraulic servo system: building a force balance equation according to the Newton's second law, and building a pressure dynamic equation and a state space equation accordingto the dynamics of a hydraulic system; designing a mapping function and an adaptive law: designing an adaptive law to learn system parameters, and designing the mapping function to ensure that the parameters are self-adaptive and bounded; secondly, designing an expansion disturbance observer: based on an expansion disturbance observation theory, respectively designing the observer for the matching uncertainty and the mismatching uncertainty, and learning; and finally, performing controller design: performing feed-forward compensation on uncertainty learning, designing a robust controller, andrealizing a tracking effect. According to the method, common parameter uncertainty and unmodeled interference problems in an electro-hydraulic servo system are considered, an expansion interference observer is fused based on a traditional self-adaptive control method, and high-performance position control is achieved.

The invention discloses a calculation method for predicting an influence of swirl distortion intake air on the performance of an aero-engine, which organically combines a three-dimensional physical model with a two-dimensional multi-sub parallel engine part model and is suitable for analyzing the influence of complex swirl distortion intake air on the performance of the whole aero-gas turbine engine. The method comprises: describing engine impeller mechanical part by adopting a three-dimensional body force model, wherein a multi-stage gas compressor and a turbine are included; describing a combustion chamber and an exhaust nozzle by adopting a two-dimensional multi-sub parallel engine part model; setting a numerical value transmission interface between the three-dimensional model and the two-dimensional model to realize conversion between three-dimensional calculation and two-dimensional calculation; supplementing a rotor kinetic equation and an engine control rule to realize work balance calculation between the turbine and the gas compressor, and determining the rotating speed of the engine in real time; and applying large-scale rotational flow distortion inlet air to the boundaryof an inlet of an air compressor, and obtaining the influence of rotational flow distortion on the performance of the whole aero-engine and the internal distortion flow field characteristics of a compression system in the whole aero-engine environment on the basis of time-marching solving.

The invention discloses a tilting mechanism dynamics optimization method and system for a tilting rotor unmanned aerial vehicle. The method comprises the steps: building a mechanical-electrical-wind multi-physical-field coupling multi-body dynamics theoretical model of a tilting mechanism, and analyzing the force, moment and motion characteristics of the tilting mechanism in a tilting process; analyzing the change rule and influence of related physical quantities of the tilting mechanism through finite element-based multi-physical field simulation, and correcting the theoretical model; on the basis of theoretical model establishment and multi-physical simulation correction of a theoretical model, a tilting mechanism experiment platform is established, and the theoretical model is verified; and optimizing the tilting mechanism on the basis of the verified theoretical model. The method has the advantages of making up the limitation of a single method, comprehensively and deeply analyzing and optimizing, accurately analyzing and optimizing and the like.

The invention relates to a method for calculating parameters of frequency and / or amplitude modulated electromagnetic pulses for adiabatic transfer processes in a quantum mechanical system with the dynamics of the quantum mechanic system described by a Hamilton Operator (H(t)) in a current system of coordinates. The inventive method consists of the following steps:a) transformation of the Hamilton Operator (H(t)) of a current system of coordinates into a subsequent system of coordinates for describing the time dependency of the change in direction of the Hamilton Operator (H(t));b) determination of the self-commutation of the Hamilton Operator (H(t)) at a time t and the Hamilton Operator (H(t′)) at a time t′ in the corresponding system of coordinates, whereby a differential equation system is obtained;c) calculation of the parameters from the differential equation system thus obtained.

The invention discloses an experimental system and an experimental method capable of simulating a gear transmission non-inertial system environment, which relate to the field of aviation power transmission. The experimental system capable of simulating the gear transmission non-inertial system environment comprises a gear transmission experiment table, a linear motion platform and an electric vibration table, wherein the linear motion platform drives the gear transmission experiment table to do horizontal linear acceleration motion, so as to simulate a gear transmission linear acceleration non-inertial system environment; the electric vibration table drives the gear transmission experiment table to rotate back and forth around a horizontal shaft, so as to simulate a gear transmission pitching non-inertial system environment; and the electric vibration table drives the gear transmission experiment table to rotate back and forth around a vertical shaft, so as to simulate a gear transmission yawing non-inertial system environment. According to the experimental system and the experimental method, the dynamic experiment of a gear transmission system during basic fixation can be carriedout, the non-inertial excitation of the gear transmission system during the maneuvering flight of an aircraft can be simulated, and the vacancy of the experimental research in the aviation power transmission field considering the non-inertial system environmental conditions in China is made up.

The invention relates to an aircraft-missile separation dynamics similar wind tunnel test method, which aims to realize dynamics similar simulation of an aircraft-missile dynamic separation process ina wind tunnel and obtain motion / aerodynamic characteristics of a carrier missile in the separation process under the action of an aircraft interference flow field, and belongs to the field of test aerodynamics. The method comprises the following steps of (1) introducing a design variable to obtain a dynamics similar parameter design method suitable for engineering, (2) according to a dynamics similar parameter design method, obtaining dynamics similar parameters of the carrier missile, (3) obtaining a wind tunnel test model of the carrier missile by utilizing the dynamics similar parametersof the carrier missile, and (4) increasing the initial separation speed or the ejection force in the wind tunnel test process, and performing test correction on insufficient vertical acceleration simulation to obtain a more realistic carrier missile separation motion characteristic result.

The invention discloses an aerodynamic / control integrated coupling simulating technology in the aircraft maneuvering process, and relates to the field of computational fluid mechanics and the field of control systems. The main work implementing process includes the steps of generating a control signal through the compared deviation of the attitude angle of an aircraft and a control target, outputting the control signal to a PID controller module, generating a rudder deviation angle signal after computation, outputting the rudder deviation angle signal to a dynamic mesh module, deflecting a rudder face to a corresponding angle through a dynamic mesh technology, obtaining a dynamic flow field existing after deflection of the rudder face through a Navier-Stockes equation module, generating aerodynamic force and torque signals, outputting aerodynamic force and torque to a rigid body dynamics equation and a kinematical equation, obtaining the flight attitude of the next moment, transmitting the new flight attitude to the PID controller module, and forming a closed-loop numerical simulating circuit. The high-precision simulation of a flight control system is achieved, and the technology can be used for evaluating performance of the flight control system and studying the influences of the aerodynamic force unsteady effect on the control system.

The invention provides a system and method for analyzing the influence characteristics of a disturbance gravitational field to different forms of ballistic trajectories by using a multi-assignment method. The system is constructed based on the idea of modular construction, has high calculation speed and high precision, can adapt to the requirements of analyzing the influence characteristics of disturbance gravitation of different tasks and different forms of ballistic trajectories, and improves the reliability of an analysis result. The system provided by the invention has the advantages of providing a good interactive interface, integrating a general guided missile dynamics model with a disturbance gravitation computing method library, and facilitating the operation and the function expansion of the system.