457 results about "Multi body" patented technology

The MULTIBODY AIRCRANE performs relative positioning, predictive control, and ballast control to achieve very heavy-lifting tasks on land or sea. Such tasks allow station keeping and precise transfer of very heavy payloads between ships underway. This scalable multibody system features three subcomponents: AIRSHIP, SKYCRANE and LOADFRAME. This semi-autonomous system combines aerodynamic (kinetic) and aerostatic (buoyancy force) lift with efficient power and propulsion. During low-speed flight, the Airship and Skycrane are decoupled but linked via a reelable Tether Control Line. Beneath the Skycrane, centered on its hull, a patented NIST (National Institute of Standards and Technology) RoboCrane (featuring a computer controlled six degrees of freedom (DoF) cabling system,) is attached, to precisely suspend and control a Loadframe, with or without payload. During subsonic forward flight, these Airship and Skycrane are coupled as a single airframe (fuselage and delta wing.)

The invention relates to a fatigue life prediction system for a vehicle body structure of a vehicle in the technical field of vehicle design. The prediction system adopts a road spectrum fitting module to establish a combined road spectrum suitable for a field test; a vehicle body loading spectrum acquisition module is adopted to establish an entire vehicle multi-body rigid-flexible coupled model so as to extract the load-time-history at a connecting passage of the vehicle body and a chassis as the input of vehicle body excitation; an automobile body structure dynamic response analysis module is adopted to establish a finite element model of the vehicle body so as to obtain the static stress history generated by gravity and the dynamic stress history generated by road surface excitation of the vehicle body when the vehicle is under the excitation of the combined road spectrum; a dangerous position identifying module of low fatigue life of the vehicle body is adopted to quickly search dangerous positions of low fatigue life through an S-N method and a Miner linear accumulated damage model, and determine the multiaxial stress state of the dangerous positions by using 'biaxiality' analysis; and a fatigue life prediction module of the vehicle body structure is adopted to predict the fatigue lives of the dangerous positions accurately. The fatigue life prediction system for the vehicle body structure can improve the speed and the precision of the fatigue life prediction for the vehicle body structure so as to provide a reference for a real vehicle test.

The invention provides a multi-constraint locus planning method of a spatial free floating mechanical arm. The method can satisfy requirements for dynamic coupling, joint driving capability limitation, arresting opportunity and multiple optimizing indexes of a spatial robot. A driving joint motor realizes an autonomous arresting task to a non-cooperative object. The multi-constraint locus planning method comprises the steps of establishing a multi-member dynamic model of the spatial robot; establishing the locus of each joint of the mechanical arm based on a Bessel curve, converting constraint and optimizing index functions in a joint locus designing process to function of a Bezier curve control point, so that locus programming is finally represented by the Bezier curve control points as a nonlinear optimization problem of the optimizing parameter; converting the locus planning problem of the spatial robot to a multi-constraint and multi-object optimization problem, performing searching on the optimization problem by means of a nonlinear optimization method, obtaining an optimal solution, and finishing multi-constraint locus planning of the spatial free floating mechanical arm.

A system is provided for full-vehicle analytical road-loads prediction, which reduces the time and cost of modeling tires and tire-road interface, using road load simulations rather than actual measurements. The system includes a method to perform tire tests in a virtual environment, a road-load tire model for simulations in multibody environments; a tire model for FE simulations; and a comprehensive graphical user interface to support the user in all the steps of the analytical process.

The invention relates to a multi-body dynamic quick analysis modeling method for a rotary steering drilling system. The method comprises the following steps of: (1) establishing a structural unit mechanical model according to structural information of the drilling system; (2) establishing constraint models which comprises a speed constraint model, an angular velocity constraint model, a rigid body-beam clamped constraint model and a beam-beam clamped constraint model; (3) establishing an acting force model; (4) establishing a drilling system parameterized model; and (5) importing a computation model file into a multi-body dynamic simulation program to perform dynamic analysis of the drilling system so as to finish modeling. Since the mechanical model of the drilling system is established on the basis of a multi-body dynamic basic principle, rotary motion and dynamic analysis of rotary steering whole well drill string system are realized, and a well bore path is dynamically predicted. The method can be widely applied to the fields of oil-gas fields and coal bed methane exploitation.

The invention discloses a real road spectrum based electric automobile battery pack structure fatigue life prediction method. The method mainly includes electric automobile road load condition setting, road load spectrum acquisition and analysis, integral automobile multi-body dynamic model establishment, multi-body dynamic model transfer function acquisition and load spectrum iteration and fatigue life prediction. By adoption of a half-testing half-simulation iteration method, a real load spectrum of an electric automobile is obtained, battery pack structural load accuracy is guaranteed, highengineering practicality is realized, and expensive bench equipment input is avoided, so that low cost is realized. By battery pack structure fatigue life prediction according to a multi-axial fatigue theory and a broadband random fatigue life prediction method, low calculation amount and high prediction precision are realized.

The invention discloses a recognition method of a critical geometrical error source of a machine tool and belongs to the technical field of machine precision designing. The recognition method of the critical geometrical error source of the machine tool is characterized by comprising the steps that the machine tool is abstracted into a multi-body system according to the structure and motion characteristics of the machine tool, relevance of parts of the machine tool is described by a topological structure and a low-order body array, a generalized coordinate system is built in the multi-body system, coupling relationship of error amounts of parts of the machine tool is described by a homogeneous transformation matrix, a characteristic matrix and a motion equation of the relative movement between two adjacent bodies of the machine tool are elicited, a precision model of a machining center is built, an ordinary mathematical model used for error sensitivity analysis of a four-shaft machine tool is built with a matrix differential method according to the precision model of the precision horizontal machining center, influence degrees on the whole space error of all error elements are compared by calculating the geometrical error sensitivities of all parts, and finally the critical error source influencing the machining precision of the machine tool is recognized.

A method and engine for simulating a multi-body system, the method or engine including code for determining collision impulse over a time period for a plurality of colliding bodies in the system. An admissible function is determined from the collision impulse and resembles true contact force from the collision impulse. Complete contact force change during collision is derived from the admissible function.

The invention provides a method for analyzing the machining precision reliability sensitivity of a numerically-controlled machine tool, belongs to the field of machine tool precision design, and particularly relates to a space error modeling method of a three-axis machine tool and a method for analyzing the machining precision reliability and the machining precision reliability sensitivity of the machine tool. A multi-body system motion feature analysis method is used for setting up a space error model of the machine tool, and combined with a Monte-carlo digital analogy method for analyzing the machining precision reliability of the machine tool, and the degree of influence on the machining precision reliability from the wave action of all items of geometric errors of the machine tool, so that the critical geometric errors influencing the machining precision reliability are identified. Guiding advice can be given for designing, assembling and machining of the machine tool, and the machining precision reliability of the machine tool is improved fundamentally.

The invention discloses a detection method for geometrical errors of a rotation shaft of a five-axis numerical control machine tool, belongs to the technical field of machine tool precision detection, and relates to a detection and identification method for the geometrical errors of the rotation shaft of the five-axis numerical control machine tool. The detection method comprises the steps that image information of a concentric target are collected by a binocular camera and used for representing the actual movement information of the rotation shaft, the three-dimensional coordinate information of a feature point is acquired finally through camera calibration and image processing, and the movement track represents the space movement track of one point on the rotation shaft; and through combination of a multi-body system theory of the machine tool and a subcoordinate transformation theory of the machine tool, the errors PIGE having no relation to the position of the rotation shaft and the errors PDGE having a relation to the movement position of the rotation shaft are identified and measured. The method effectively achieves detection and identification of the geometrical errors of the rotation shaft of the machine tool, the measurement process is simple and fast, and the measurement efficiency is high. The requirements for the operation track of the machine tool are simple in the measurement process, cooperation with other shafts is not needed, and other shaft linkage errors are avoided.

The invention provides a three-axis numerical control machine tool key geometric error identification method based on global sensitivity analysis, belongs to the field of machine tool accuracy design, and particularly relates to a three-axis machine tool space error modeling method and a three-axis machine tool geometric error global sensitivity analysis method. On the basis of machine tool space error models built through the multi-body theory and geometric error measurement, global sensitivity analysis is conducted on various geometric errors of a machine tool, and influence on machining accuracy of the coupling effect of the geometric errors is obtained. A new machine tool design concept is provided, and the problem of machine tool accuracy is fundamentally solved. Guiding suggestions can be put forward for practical assembly and machining, therefore, output of errors is reduced, the machining accuracy of the numerical control machine tool is improved, and the problem of the machine tool accuracy is fundamentally solved.

The invention relates to an interplanetary transfer orbit design method, in particular to a transfer orbit design method from a periodical orbit which is near dynamic balance points of a three-body system to a small celestial body and belongs to the technical field of aerospace. Firstly, based on the periodical orbit which is near the dynamic balance points of the three-body system where a detector is located, an initial state of the detector x0=[ r0, v0] is assumed. Secondly, a speed increment delta v is exerted along a tangential direction so that the detector sets off from the periodical orbit near the dynamic balance points. Based on a multiple-body model, relations between the detector and a distance df of the detector and the target small celestial body, a flying period tf and the tangential direction speed increment delta v are built up when the detector flies across the target small celestial body is built. Through an optimizing algorithm, an initial value of the transfer orbit is obtained when the fight distance df is minimum. Finally, a secondary-level differential correction method is used based on the initial value to obtain orbit parameters which can meet two point boundary values. The interplanetary transfer orbit design method can achieve rapid design of flight from the periodical orbit which is near the dynamic balance points of the three-body system to the small celestial body, calculation amount is small and efficiency is high.

The invention provides a method for calculating particles on a GPU by utilizing a multi-body interaction model, comprising the following steps: storing the attribute information of particles in a particle system and labeling information of an adjacent particle of each particle to a system memory on a computer loaded with the GPU; transmitting the attribute information and the labeling informationto a global memory of the GPU; opening up a storage array for the acting force applied by each particle to the adjacent particle thereof in the global memory; distributing an individual calculation threading in the GPU for each particle; taking down all stresses of the particles calculated in the threading according to the established multi-body interaction model between the particles; simultaneously storing the stress of each particle to the adjacent particle thereof; reading in the stress of the stored adjacent particle of each particle from the global memory; adding the stresses to the particles with corresponding labels to obtain completed acting force to the particles; and calculating potential energy of each particle on the GPU, outputting the results to the system memory, and carrying out statistics and calculation on the average potential energy of a single particle by CPU.

The invention provides a space six-degrees-of-freedom mechanism used for a hypersonic wind tunnel multi-body separation test. The mechanism comprises Z, X and Y three degrees of freedom straight-line motion mechanisms and [beta], [alpha] and [gamma] three degrees of freedom angular displacement motion mechanisms. The six-degrees-of-freedom are realized layer by layer and are connected step by step, and in terms of structure, embedment integration is achieved by a box stacking mode. A Z-direction mechanism, an X-direction mechanism and a [beta] mechanism are sequentially overlapped from bottom to top, and a Y-direction mechanism and a [alpha] mechanism are in embedded connection from outside to inside. A [gamma] mechanism is fixedly connected with the [alpha] mechanism through a bent blade, and is individually arranged in a wind tunnel flow field. Each of the Z-direction mechanism, the X-direction mechanism and the Y-direction mechanism adopts two driving assemblies in symmetric arrangement, so that the power and the size of a driving motor are effectively reduced, and the overall stability of the mechanism is improved. The [beta] mechanism and the [alpha] mechanism adopt line-to-arc mechanisms for implementation, so that overlapping of traditional three degrees of freedom rotation pairs is prevented, and the mechanism cantilever length is shortened. The structure is compact, the rigidity is good, andsix-degrees-of-freedom movement of high speed, high precision and high bearing capacity is achieved.

The invention discloses a road load test method and system. The method comprises the steps of: with a sample vehicle running on roads on a test site, extracting an original road load spectrum; filtering the original road load spectrum, and obtaining the road load spectrum which has been filtered; based on a multi-body dynamics automobile model and in accordance with road load spectrum which has been filtered, obtaining the road load spectrum for carrying out the simulation through virtual iteration technology; through load decomposition, obtaining load data at each preset connection point of the vehicle body and a chassis; and based on the load data, calculating a first fatigue endurance value of each preset connection point. The method can obtain the actual original road load spectrum on different test sites, and based on the actual original road load spectrum, can calculate the fatigue life value, and can further predict a more accurate fatigue life of the vehicle, which can effectively increase the fatigue endurance of the vehicle body and provide the effective basis for the optimization and improvement of a vehicle structure in vehicle design.

The invention discloses a security judging method of a rail irregularity state in the technical field of railway security operation control. The security judging method comprises the following steps of: establishing a vehicle rail model in multi-body dynamic simulation software; determining a rail irregularity parameter; inputting the rail irregularity parameter into the vehicle rail model and generating an executable code in the multi-body dynamic simulation software; inputting actually-measured rail irregularity data into the executable code, and operating the executable code to obtain wheel-rail acting force; calculating a security evaluation index of the rail irregularity state according to the wheel-rail force; processing the calculated security evaluation index of the rail irregularity state; and comparing the processed security evaluation index of the rail irregularity state with a pre-set security standard so as to obtain a security judging result of the rail irregularity state. Compared with the conventional security judging method of the rail irregularity state, the security judging method provided by the invention is more accurate in judging result.

The invention provides a dynamics simulated analysis method on the basis of a multipoint positioning flexibility tool system. The dynamics simulated analysis method on the basis of the multipoint positioning flexibility tool system includes steps of firstly, preparing and mounting an ADAMS multi-body dynamics simulation software; secondly, establishing a model of a mechanical system; thirdly, rightly establishing various coordinate systems of the mechanical system; fourthly, building a dynamics model of the multipoint positioning flexibility tool system according to the various coordinate systems of the mechanical system set in the third step; fifthly, detecting the dynamics model set up in the fourth step by the ADAMS multi-body dynamics simulation software; sixthly, analyzing running results of the dynamics model; seventhly, optimizing the system to obtain the optimal solution according to the structural design scheme. The dynamics simulated analysis method basically solves the problem that an existing dynamics simulation analysis method is low in systematized degree, narrow in application range, poor in interference resistance and slow in simulation analysis.

The invention provides a spacecraft dynamics modeling method. The method comprises the following steps of: replacing a liquid sloshing equivalent mechanical model with an equivalent pendulum, enabling a closed loop topology structure to be equivalent to an open loop tree topology structure, defining a coordinate system at a hinge joint, defining a basic contact operator, characterizing elastic displacement of a flexible body, and performing recurrent calculation on the force and speed of the flexible body; and judging whether systematic calculation on a dynamics model is a forward dynamics modeling process or a backward dynamics modeling process, correspondingly substituting the forward dynamics modeling process or the backward dynamics modeling process, and deducing a system dynamics equation. The method provided by the invention is capable of not only meeting the precise modeling requirement, but also simplifying the design process, saving a lot of workload, accelerating the spacecraft development period, realizing high-precision high-efficiency dynamics modeling of a large flexible cable antenna spacecraft, achieving modeling of a flexible multi-body system capable of calculating closed loop spacecraft configuration in a simplest mode, and saving a lot of tedious and hard works.

The invention mainly relates to a multi-body dynamics-based automotive suspension, a simulation test and design platform of vibration reduction system, and an analysis method of the multi-body dynamics-based automotive suspension. The analysis method comprises the following steps of: firstly, selecting a three-dimensional parametric model of the automotive suspension or an entire car from a three-dimensional parametric standard model base through an ADMAS/View software interface; secondly, selecting road files of appropriate tire files from a tire file library and a road file library; thirdly, modifying design parameters; fourthly, selecting a simulation test condition, performing a simulation analysis and outputting a simulation analysis result; and finally, determining an optimum design object by using the analysis result, and performing optimum design on design variables. The invention has the following advantages: firstly, a computer technique, a multi-body dynamics theory and an automotive test standard are comprehensively utilized to realize simulation analysis of automobile performance under a virtual environment; secondly, a parameterized modeling technique is utilized to realize model reuse of the simulation analysis of an automobile; and finally, an optimum design theory is utilized to realize the optimum design of the design parameters of the automobile. The multi-body dynamics-based automotive suspension, the simulation test and design platform of the vibration reduction system, and the analysis method are favorable for improving the automobile design efficiency and quality, and quickly respond to quickly changing international and domestic markets.

The invention relates to a complete automobile collision simulation method on the basis of the parameterization design and belongs to the field of a nonlinear finite element and nonlinear multi-body dynamics. The method comprises the following steps of: calculating collision force and a stroke of each power-absorbing component by nonlinear finite element software; according to series/parallel power-absorbing characteristics of the power-absorbing components, determining an equivalent total rigidity of power adsorption devices between carriages; then establishing a complete automobile collision dynamic performance analysis model on the basis of the parameterization design; and combining the complete automobile collision dynamic performance analysis model with constraint conditions to obtain an optimal combination of the power-absorbing characteristics of the power-absorbing components so as to obtain the optimal values of motion and a longitudinal load of each carriage in the complete automobile collision process. In the method, the nonlinear finite element and the nonlinear multi-body dynamics are combined to carry out complete automobile collision simulation research; the nonlinearity and the elastic plastic deformation of a material are simulated by the established model; and meanwhile, the collision simulation analysis of an automobile head is expanded to the complete automobile.

Provided is a method for calculating dynamic characteristics of a contactor based on a piecewise linear kinetic equation, and belongs to the technical field of basic research design of general characteristics of contactors. The method comprises the steps that according to structural features of the contactor, segmentation is conducted on a contactor action process, plane collision and a continuouscollision force model with energy loss considered are used for being equivalent to a collision process, by means of the multi-body system kinematics based on a restrain method and a dynamic method, studying of the collision bounce situation of a contactor mechanical system under the action of external force is completed, and finally, dynamic characteristic calculation of the contactor with collision bounce considered is completed in combination of a coupling calculation method. The method has the advantages that the time-dependent situation of electromagnetic parameters such as the coil current and electromagnetic force in a working process of the contactor can be obtained, the electromagnetic dynamic characteristics of the contactor can be reflected more accurately, and errors are controlled within 5%; the bounce situation of an armature and a moving contact of the contactor can be reflected more really, and errors are controlled within 5%.