75 results about "Virtual work" patented technology

The invention discloses an aircraft shell surface quality detection method. According to the method, a passenger cabin pressure difference curve and a shell outer surface temperature curve are calculated to obtain a pressure difference change node and a temperature difference change node respectively, and then partitioning is carried out to obtain phase thermoelastic coupling partitions; when a temperature difference change node reaches a phase change threshold value, performing beta-phase to alpha-phase transformation on the polyvinylidene fluoride microcapsule premixed in the finish paint, and forming a polarized memory cavity at a defect cementing position; when a voltage difference change node reaches a peak value, triggering a polarized memory hole to release charges, exciting a high-order thin film elastic wave, and performing integer ratio phase locking on the high-order thin film elastic wave and a natural vibration wave of a machine body to obtain a defect harmonic signal; carrying out acoustic-mechanical coupling calculation according to the amplitude of the defect harmonic signal to obtain a virtual work increment, and recording the virtual work increment to a damage matrix; and performing multi-leg accumulation calculation on the virtual work increment, and outputting a defect early warning signal when an accumulation value exceeds a material fatigue critical value. According to the invention, the hidden fatigue defect of the surface of the aircraft shell under the dynamic load can be detected.

The invention discloses a complex terrain adaptability control system for a rescue robot, and belongs to the technical field of robots. According to the invention, full-closed-loop control is realized through the instruction layer, the hardware layer, the control layer and the monitoring layer. The control layer takes a posture adjusting module as a core, is linked with a PID (Proportion Integration Differentiation) and an impedance controller, and is combined with forward / reverse kinematics and suspension detection to realize accurate correction of a joint angle; the hardware layer feeds back attitude, joint movement and contact force data in real time by means of multiple sensors; meanwhile, a whole vehicle kinetic equation is established based on a spiral theory and a virtual work principle to deduce a contact force component, and a sliding rate is defined to quantify traction characteristics. According to the invention, through fusion of multi-module cooperation and mechanical modeling, organic unification of attitude control, force control flexibility and traction performance monitoring is systematically realized, and a complete attitude-force-traction cooperative control system is constructed.

The invention discloses a robot intelligent management and control system for energy conservation and efficiency improvement of a cold end of an indirect cooling auxiliary unit, and belongs to the technical field of intelligent management and control, the robot intelligent management and control system comprises an initial evaluation module, a dynamic planning module and a feedback monitoring module, obtaining a scaling thickness distribution diagram and a scaling coverage rate, and generating a fin flow channel matrix model; the dynamic planning module is used for dividing virtual operation blocks, constructing a scaling planning path in combination with a cleaning index, carrying out rapid rough sweeping, carrying out cavitation early warning, and processing cavitation early warning through a hierarchical control architecture; and the feedback monitoring module is used for constructing a quality deviation set, screening out substandard virtual operation blocks, calculating and correcting priorities, sorting and grading, optimizing and correcting parameters by utilizing a genetic algorithm, and performing feedback regulation and control, so that the cold end heat exchange efficiency is improved to achieve an energy-saving target, a fin structure is protected, and the service life of equipment is prolonged.

The invention discloses a method for rapidly evaluating the flexural rigidity of a bridge under vehicle-induced excitation, and belongs to the technical field of flexural rigidity evaluation of variable cross-section beams. The method comprises the following steps of: firstly, acquiring a bridge time-history response by adopting vehicle movement loading, separating a power component by utilizing a VMD method, then identifying a main frequency of an IMF component through FFT, removing the power component higher than a bridge fundamental frequency, and reconstructing a bridge actual measurement quasi-static time-history response; then, an axle effect in bridge actual measurement quasi-static time history response is eliminated, an influence line recognition model is established, and Tikhonov regularization is introduced to further solve a deflection influence line; then deriving an analytic solution of a deflection influence line of the variable cross-section continuous beam based on a virtual work principle, establishing a mathematical relationship between the flexural rigidity and the deflection influence line, and identifying the flexural rigidity of the bridge through the deflection influence line based on the mathematical relationship to obtain flexural rigidity distribution of the full bridge; finally, multiple evaluation indexes are defined and calculated, the bending rigidity distribution of the full bridge is comprehensively evaluated, and the method has the advantages of being good in engineering applicability and high in safety evaluation innovativeness.

This application discloses an impedance control method, comprising: performing dynamic modeling to obtain a closed-form dynamic equation in joint space; obtaining an expression for the driving force based on the closed-form dynamic equation; obtaining the relationship between the rope velocity vector, rope tension vector, joint velocity vector, and joint equivalent torque based on the principle of virtual work; calculating the rope tension from the joint torque, where the driving force solution can be expressed as the sum of a least-squares solution and an arbitrary null-space solution; analyzing the joint torque output capacity under rope tension constraints; establishing an ideal mathematical model for the tension transmission process of the rope-driven joint and analyzing the transient coupling effect under rope tension control in joint space; performing joint motion analysis under joint tension control in joint space; and establishing a target impedance model in joint space. This application effectively eliminates coupling phenomena in the tension control process and improves the active compliance of a rope-driven serpentine manipulator.

The invention provides a control method and system for a five-degree-of-freedom marine crane under a non-inertial system, and relates to the technical field of automatic control of cranes. The method comprises the following steps: acquiring a real-time state variable of the crane under a non-inertial system; the state variables are input into a self-adaptive radial basis function neural network, a lumped disturbance estimated value is obtained, and the neural network is designed based on a five-degree-of-freedom dynamical model established by utilizing a Lagrange equation and a virtual work principle under a ship coordinate system and considering ship six-degree-of-freedom motion and installation position offset; calculating a tracking error function according to the state variable and the expected trajectory; and inputting the disturbance estimation value and the error function into a feedback controller, calculating to generate a control torque, and outputting the control torque to an execution mechanism to drive the crane to track an expected trajectory and suppress load swing. According to the method, direct modeling and control under a non-inertial system are realized, the problems of coordinate transformation disturbance and singularity caused by inertial system modeling are solved, and the trajectory tracking precision and the anti-interference robustness are improved.

The invention discloses a synchronous bidirectional coupling solving method for large deformation of a flexible slender beam under uniformly distributed pressure based on an accurate load stiffness matrix, and relates to the field of computational mechanics. According to the method, a local curve coordinate system and a uniformly distributed pressure vector function are constructed through an absolute node coordinate Euler-Bernoulli beam unit discrete beam structure, a unit external force vector is derived based on a virtual work principle, and a precise load stiffness matrix is obtained through a vector value function differential rule. The load stiffness matrix and the elastic tangent stiffness matrix are synchronously assembled in the Newton-Rafson iteration step, and synchronous bidirectional coupling solution of the load and the configuration is achieved. According to the method, the numerical value loading limit of a traditional method is broken through, error accumulation is avoided, the calculation stability and precision are improved, the large deformation and even post-buckling behavior of the flexible slender beam under the uniformly distributed pressure can be accurately analyzed, and the method is suitable for design optimization of related equipment in the fields of ocean engineering, mechanical engineering and the like.

The invention discloses a recruitment post recommendation method and device based on career prediction, and relates to the technical field of online recruitment. The method comprises the steps of obtaining user portrait data of a job seeker; predicting the next virtual work experience according to the resume information of the job seeker; vectorizing the next segment of virtual work experience to obtain vectorized representations of a plurality of virtual work experiences, and adding the vectorized representations to the user portrait data; performing vector retrieval on the vectorized representations of all the recruitment post information to obtain a plurality of vectorized representations of the recruitment post information matched with the vectorized representation of the virtual work experience; and filtering and sorting the recruitment post candidate set according to the screening conditions, and taking the sorted recruitment posts as recruitment post recommendation results of the job seekers. According to the method, strong dependence on user dominant requirements, resume integrity and behavior data is remarkably overcome, and the problems of fuzzy job application requirements, data sparsity and cold start are effectively solved.

The application discloses a rotor coupling dynamics calculation method of complex three-dimensional shape layout. A coordinate conversion relationship caused by a front protrusion / after-sweeping / downward-reversing configuration is established; nonlinear elastic deformation of elastic blades waving, oscillating and twisting and nonlinear coupling relationship among them are described; nonlinear motion caused by the complex three-dimensional shape layout is described based on the coordinate conversion relationship and the nonlinear coupling relationship; and the relationship among strain energy, kinetic energy and virtual work of external force of the rotor is established based on the Hamilton principle according to the description of the nonlinear motion, and a finite element method of a 15-degree-of-freedom beam element is used to establish a rotor dynamics equation. The application can effectively reflect the structural coupling characteristics and coupling degree of the waving-torsion direction caused by the front / rear sweep of the blade tip, effectively reflect the structural coupling characteristics and coupling degree of the oscillation-torsion direction caused by the upward / downward reversal of the blade tip, and effectively reflect the rotor dynamics characteristic behaviors caused by the three-dimensional shape of the blade.

The invention provides a path adjustment method and device, equipment and a storage medium. The method comprises the steps that an operation interface is displayed, the operation interface comprises a virtual path, a virtual operation topographic map and a path angle adjusting control, the virtual path is displayed in the virtual operation topographic map, and the path angle adjusting control is used for adjusting the angle of the virtual path in the virtual operation topographic map; in response to a first operation on the path angle adjustment control, the path angle adjustment control is rotated to a target scale, and the target scale corresponds to a first angle of the virtual path in the virtual operation topographic map; determining an angle change value based on the target scale; and adjusting the virtual path to the first angle according to the angle change value. According to the method, the angle of the virtual path in the virtual operation topographic map can be directly adjusted through the path angle adjusting control, the virtual path and the virtual operation topographic map are visually displayed through the operation interface, the adjusting efficiency and accuracy are improved, the adjusting effect is fed back in time, and then the path optimization efficiency is improved.

The object of the present invention is to provide a control method for a parallel four-wheel-legged robot. Based on a 12-degree-of-freedom four-wheel-legged robot with a symmetric parallel mechanism, a corresponding control method is proposed. During the swing phase of the robot, a wheel dynamics compensation method based on the principle of virtual work is proposed in combination with the decomposed virtual model control to improve the model control accuracy. At the same time, in order to achieve attitude decoupling, the present invention also proposes a corresponding attitude control strategy and a ramp adaptive strategy. Combining the dual advantages of wheels and legs, a rolling control method and an attitude control strategy in the wheel-leg mode are proposed to enable the robot to pass multiple wavy obstacles with a height of 0.15 m and a slope of 41.41° unilaterally at a speed of 3.2 m / s in the simulation.

The present application belongs to the field of elastic motion modeling of air defense missiles, and particularly relates to an elastic motion modeling method for air defense missiles with trajectory control and direct-gas combined control, aiming at solving the problem that the traditional modeling method is insufficient in covering trajectory control force, thus being difficult to realize accurate modeling of the elastic motion of air defense missiles with trajectory control and direct-gas combined control. The present application comprises: calculating the kinetic energy T of the missile system caused by the bending deformation of the elastic missile body, the elastic potential energy U of the missile system, and the damping energy D of the missile system caused by the bending deformation of the elastic missile body; calculating the generalized force Q acting on the missile body corresponding to the virtual work through the virtual work principle i ; based on the kinetic energy T of the missile system, the elastic potential energy U of the missile system, the damping energy D of the missile system, and the generalized force Q i , constructing the dynamic equation of the elastic missile body through the Lagrange equation. The present application corrects and improves the problem of insufficient coverage of trajectory control force in the traditional modeling method, and has high accuracy and precision in the elastic motion modeling of air defense missiles with trajectory control and direct-gas combined control.

The invention discloses a dynamic modeling and performance analysis method for a quartz double-end tuning fork resonator, and the method comprises the steps: constructing a high-order displacement field which meets the condition that the free boundary stress is zero in prior to describe the deformation of a mass block, and employing a coupling scheme based on a virtual work principle; the tuning fork arms and the mass block are integrated into an energy conservation dynamic self-consistent system. According to the method, the linear characteristic frequency and modal of the system are solved, then geometric nonlinearity is introduced, and the amplitude-dependent nonlinear frequency response is accurately calculated through an iterative algorithm. According to the dynamic modeling and performance analysis method for the quartz double-end tuning fork resonator, the fundamental frequency prediction error is reduced to 0.34% from 1.6% of a traditional model, and the relative precision is improved by 79%; meanwhile, the non-physical residual stress at the free boundary is restrained to the magnitude of the maximum stress in the domain, the boundary stress distortion is fundamentally eliminated, and a reliable theoretical tool is provided for accurate design and optimization of the high-performance MEMS resonator.

The invention provides a numerical simulation method for fluid-structure interaction vibration of wind tunnel airflow and a tunnel wall structure, and belongs to the technical field of wind tunnels. Geometric parameters of a wind tunnel section are obtained, a multi-layer grid sequence is established, an implicit Runge-Kutta format and an explicit Newmak method are adopted to solve a flow field and a structure field respectively, and the wind tunnel airflow and tunnel wall structure fluid-structure interaction vibration is obtained. Mesh deformation is realized by using tightly-supported radial basis function interpolation, a volume conservation constraint is introduced, an interface projection matrix is constructed based on a virtual work equivalence principle to transmit interface data, a force balance and displacement coordination constraint is introduced, and coupling iteration convergence is accelerated through an inverse Broyden formula. A density gradient shock wave sensor is adopted to drive grid adaptive encryption and a mixed indicator function to control turbulence model switching, and the technical problems that wind tunnel section airflow and wall surface structure fluid-structure interaction vibration numerical simulation calculation is low in efficiency and insufficient in precision are solved.

The invention discloses a rotary steerable drilling tool, a posture correction method and system thereof and a medium, and particularly relates to the technical field of oil field drilling engineering, and the method is technically characterized in that the method comprises the steps that the internal friction torque and the eccentric torque of the rotary steerable drilling tool during underground work are obtained; dispersing the drill string into a structural model comprising at least one beam unit by utilizing a finite element method, and analyzing the dynamics of the rotary steering drilling tool by utilizing the structural model in combination with a virtual work principle to obtain a dynamic analysis result of the rotary steering drilling tool; constructing a first relation model by using the internal friction torque, the eccentric torque and the drilling fluid flow; obtaining attitude data of any hole drift angle and a tool face angle of the rotary steering drilling tool, and constructing a second relation model between the theoretical measured value of the well track and the actual measured value of the well track; and constructing a well track correction matrix error model through the first relation model, the second relation model and a preset flow feed-forward compensation algorithm.

The present invention discloses a method for evaluating the spatial posture of a conceptual configuration of a branched-chain driven parallel robot. First, a kinematic analysis method based on singular values ​​is used to judge the reachability of all the terminal postures of the branched-chain driven parallel mechanism, and the terminal posture of the branched-chain driven parallel mechanism in the reachable workspace is obtained; then, based on the screw theory and the principle of virtual work, the complete Jacobian matrix and the full stiffness matrix of the mechanism are obtained, and the stiffness performance parameters of all the terminal postures of the branched-chain driven parallel mechanism are calculated, and the stiffness performance parameters corresponding to the terminal postures of all the mechanisms are obtained; finally, according to the terminal posture in the reachable workspace, combined with the stiffness performance parameters corresponding to the terminal postures of all the mechanisms, the optimal posture set is screened and obtained. The present invention can not only quantitatively evaluate the optimal posture set, but also realize the innovative mechanism concept design that meets the needs by comparing the optimal posture sets of mechanisms with different configurations.

The invention belongs to the field of numerical control machining and manufacturing, and discloses a mechanical structure frequency response function identification method based on variable spindle rotating speed excitation. Taking cutting force borne by a tail end cutter as a quasi input signal, taking a machine tool driving shaft tracking error as an output signal, and determining a signal sampling period according to an identification precision requirement; according to the virtual work principle, the cutting force borne by the tail end cutter is converted into equivalent loads of all driving shafts of the machine tool in combination with a machine tool Jacobian matrix; then, calculating a cross-power spectrum of the input signal and the output signal and an auto-power spectrum of the input signal by using fast Fourier transform; and finally, the frequency response function of the mechanical structure can be obtained by calculating the ratio of the cross-power spectrum to the self-power spectrum. The method effectively avoids physical damage to the mechanical structure of the numerical control machine tool caused by an existing excitation identification method, has the advantages of being simple and easy to operate, and has great significance in perfecting the efficient and high-precision machining technology of mechanical parts.

The invention belongs to the technical field of protection, and particularly relates to a method and device for evaluating the damage degree of a functional gradient multilayer metal plate under a near-field explosion load. The method specifically comprises the following steps: determining the pulse pressure generated by explosion according to the spatial distribution characteristic of the peak value of the pulse pressure on a loaded surface and the attenuation change rule of the pulse pressure along with time; calculating the plastic work of the first layer of metal according to the plastic strain component expression of the first layer of metal and the incompressibility principle; according to the plastic work of the first layer of metal, the total kinetic energy of the multiple layers of metal plates and virtual work of pulse pressure generated by explosion on virtual displacement, a control differential equation of transverse displacement of the multiple layers of metal plates is obtained; solving the differential equation to obtain the maximum lateral displacement of the multilayer board, calculating the average strain rate according to the maximum lateral displacement, and updating the flow stress; the differential equation is solved again through the flow stress obtained through updating till the set condition is met, and the currently obtained maximum transverse displacement of the multi-layer board serves as the damage degree.

The invention relates to a parallel type six-degree-of-freedom force feedback master manipulator and system, and belongs to the technical field of robot teleoperation and man-machine interaction. The master manipulator comprises a frame type base, six motor modules integrated with angle and current detection units, a motor connecting rod, a platform connecting rod, a motion platform and a rocker integrated with a force sensor. A current closed loop is arranged in the motor module, and high-precision torque control is achieved. Six-degree-of-freedom motion is achieved through a spherical hinge space connecting rod mechanism formed by a motor connecting rod and a platform connecting rod. The master manipulator control unit receives the angle information of the motor, and the forward kinematics pose of the motion platform is solved through nonlinear least square numerical iteration; meanwhile, a Jacobian matrix is constructed based on the virtual work principle, and the expected generalized force at the tail end is mapped into a torque instruction of each motor, so that high-fidelity force feedback is realized. The device is compact in structure, high in rigidity and fast in dynamic response, the integrated force sensor can accurately sense the force application intention of an operator, and the device is suitable for teleoperation scenes such as nuclear environments and minimally invasive surgeries.

The present application relates to the field of material mechanical property characterization, in particular to a high-temperature thermal softening variable stiffness and strength metal elastic-plastic parameter global characterization method, comprising: obtaining strain field data and temperature field data of the test piece, and tensile load data; constructing a thermal-mechanical coupling elastic-plastic constitutive model of the metal plate, and establishing a target function of temperature-related parameters to be solved under the constraint of multiple virtual fields based on the virtual work principle; accurately identifying high-temperature thermal softening elastic parameters by using elastic stage data, and then identifying anisotropic strength thermal softening plastic parameters by using composite field data of the whole loading process under variable stiffness; the present application breaks through the condition restriction of constant stiffness when characterizing thermal-mechanical coupling properties of metal materials by using existing test methods, and can realize global accurate characterization of high-temperature thermal softening and anisotropic complex elastic-plastic thermal-mechanical coupling property parameters by only one test, thereby minimizing the number of tests and simplifying the test process.

The invention discloses a particle earth and rockfill dam large deformation calculation method based on node integration, and relates to the technical field of geotechnical engineering large deformation. The method comprises the following steps: establishing a generalized shape function and a strain displacement matrix of a proportion boundary finite element SBFEM under a Laplacian equation; under an updated Lagrange framework, state variables at Gaussian integral points of the triangular SBFEM unit are projected to nodes through a strain smoothing technology, a momentum equation is converted into a balance equation based on node integration through a virtual work principle and a Green divergence theorem, and the dynamic equation is solved through a central difference method; and when the grid distortion degree reaches a significant level, discarding the current grid and performing re-grid division. All state variables such as stress, displacement, speed and the like are concentrated on nodes of abandoned grids, so that the subsequent grid generation and calculation process can be seamlessly continued. According to the invention, continuous simulation of the whole large deformation process based on the proportional boundary finite element method is realized.

The application discloses a method for analyzing bearing capacity of two-span concrete floor slabs under column end constraints, comprising: obtaining position parameters of the concrete floor slabs, calculating displacement coefficients of different beams based on the position parameters; establishing slab plane equations of a yield line load stage based on the displacement coefficients, obtaining slab rotation angles of each slab along x and y coordinate axes based on the slab plane equations; calculating yield line load values according to the virtual work principle based on the slab rotation angles; calculating membrane force parameters based on force balance equations, moment balance equations and elliptical regions of each slab; establishing plane equations of each slab under a limit state, calculating bearing capacity increase coefficients according to the plane equations; obtaining a total increase coefficient based on the force equivalence principle, and obtaining a limit bearing capacity based on the total increase coefficient and the yield line load values. The application can make the bearing capacity of the reinforced concrete floor slabs under column end constraints have a smaller error compared with the actual situation.

The application discloses a rigidity design method of a self-standing reinforced steel chimney, and belongs to the technical field of structural engineering. Firstly, according to the chimney size of the preliminary design and the basic wind pressure value of the design, the standard value of the along-wind load and the equivalent static load of the transverse-wind vortex-induced resonance are respectively calculated, and based on the virtual work principle of structural mechanics, a theoretical solution of the top horizontal displacement of the chimney is obtained. Secondly, considering the influence of the deformation characteristics of the chimney shell and the like, the theoretical solution is multiplied by a maximum horizontal displacement correction coefficient to obtain a real value of the maximum absolute value of the horizontal displacement of the top of the chimney cylinder. Finally, whether the real value of the horizontal displacement exceeds the limit value of the specification is checked to determine whether the chimney wall thickness needs to be increased to improve the rigidity. The application is accurate and reliable, simple to calculate, can save the building materials as much as possible under the premise of ensuring the reliable rigidity of the chimney cylinder structure, and is helpful to obtain a reasonable and reliable rigidity design scheme of the self-standing reinforced steel chimney under the combined action of the along-wind load and the transverse-wind load.

A system for generating a work plan for autonomous operation of a compactor in tandem with an earthmoving machine includes a first controller that receives information pertaining to a work area on which the earthmoving machine is required to perform at least one operation. The system also includes a central controller that receives, from the first controller, information pertaining to the work area on which the compactor is required to perform the at least one operation and analyzes the work area for virtually segmenting the work area into a plurality of virtual work areas, and data indicative of a movement of the earthmoving machine through each virtual work area from the plurality of virtual work areas. The central controller determines an optimal direction of movement for the compactor based on the data indicative of the movement of the earthmoving machine, topographical conditions, as well as geometry of the work area.

This invention provides a control method and system for a five-degree-of-freedom marine crane in a non-inertial frame, relating to the field of crane automatic control technology. The method includes: acquiring the real-time state variables of the crane in a non-inertial frame; inputting the state variables into an adaptive radial basis function neural network to obtain a lumped disturbance estimate, the neural network being designed based on a five-degree-of-freedom dynamic model established in the ship's coordinate system using the Lagrange equations and the principle of virtual work, considering the ship's six-degree-of-freedom motion and installation position offset; calculating a tracking error function based on the state variables and the desired trajectory; inputting the disturbance estimate and the error function into a feedback controller to calculate and generate a control torque, which is then output to the actuator to drive the crane to track the desired trajectory and suppress load sway. This invention achieves direct modeling and control in a non-inertial frame, solving the coordinate transformation disturbance and singularity problems caused by inertial frame modeling, and improving trajectory tracking accuracy and disturbance rejection robustness.

A system for generating a work plan for autonomous operation of a compactor in tandem with an earthmoving machine includes a first controller that receives information pertaining to a work area on which the earthmoving machine is required to perform at least one operation. The system also includes a central controller that receives, from the first controller, information pertaining to the work area on which the earthmoving machine is required to perform the at least one operation and analyzes the work area for virtually segmenting the work area into a plurality of virtual work areas. The central controller also receives, from the first controller, data indicative of a movement of the earthmoving machine through each virtual work area from the plurality of virtual work areas and determines an optimal direction of movement for the compactor based on the data indicative of the movement of the earthmoving machine.

The invention belongs to the field of multi-physics field coupling modeling and simulation, and relates to a space-time interpolation mapping method for simulation data of a multi-physics field collaborative heterogeneous model. In the aspect of spatial interpolation, target point data is calculated through source point data on the basis of Shepard interpolation, so that the boundaries of physical quantities are ensured. In the aspect of space-time mapping of physical quantities such as load and heat flow, based on the virtual work principle, physical quantity data of each discrete moment of one physical field A is utilized to calculate equivalent physical quantities of unit nodes of another physical field B, and equivalence of the physical quantities of the nodes is guaranteed; and then according to the law of conservation of momentum or energy, calculating the change of momentum in the time step length of the physical field B to obtain the equivalent physical quantity of the unit node in each discrete moment of the physical field B, thereby ensuring the conservation of the physical quantity of the node. The method is suitable for data interpolation and space-time mapping links in collaborative analysis and optimization design of multi-specialty and multi-physics field heterogeneous models.

A three-dimensional layered semi-infinite foundation transient heat transfer stress coupling numerical analysis method comprises the steps that a semi-infinite domain is divided into a near-field area and a far-field area, coordinate transformation is established based on geometric similarity between similar surfaces and boundary surfaces, and a proportional boundary finite element coordinate system is formed; deriving a heat conduction and thermal stress control equation under an SBFEM coordinate system based on a variational principle and a virtual work principle, and establishing a dimensionless heat conduction matrix under a frequency domain; solving a heat conduction matrix by adopting a continuous fractional expansion method and Scherr decomposition, and realizing time domain integration through an improved fine time-history integration method (MPTSIM); under a sequential coupling framework, firstly solving a transient temperature field, and then applying the transient temperature field as a thermal load to a mechanical equilibrium equation to obtain a displacement field and a stress field; according to the method, the calculation scale and resource consumption are remarkably reduced while high precision is guaranteed, and the method is suitable for efficient analysis of the transient thermal-mechanical coupling problem in the three-dimensional layered semi-infinite foundation.

The invention provides a coupled six-degree-of-freedom elastic aircraft flight simulation method. The method comprises the following steps: step 1, modeling a kinematic equation of an aircraft; 2, according to the virtual work principle, modeling is conducted on a kinetic equation of the aircraft on the basis of the kinematic equation; 3, performing elastic correction on the airflow angle of the aircraft, and calculating aerodynamic force borne by the aircraft and corresponding aerodynamic torque according to the airflow angle subjected to elastic correction; calculating an external force, an elastic deformation generalized force and a moment borne by the aircraft; 4, substituting the external force, the torque and the elastic deformation generalized force borne by the aircraft into the kinetic equation in the step 2 to obtain a kinetic equation after elastic correction of the aircraft, and calculating flight parameters of the aircraft according to the kinetic equation so as to realize flight simulation of the aircraft; according to the method, flight simulation considering the aeroelastic effect and the rigid-elastic coupling effect at the same time can be achieved, and finally more accurate flight simulation is provided for the elastic aircraft.

The present invention discloses a robot dynamic parameter identification method based on sensitivity analysis. The method sequentially performs position inverse solution, velocity inverse solution, and acceleration inverse solution on the robot. The robot dynamic model is established using the principle of virtual work. The inertial force and inertial moment of each component of the robot are equivalent to the corresponding key points. The dynamic model of the five-degree-of-freedom robot is linearized. The parameters to be identified are separated. The initial or final values ​​of position, velocity, and acceleration are all set to 0. During the motion process, the parameter constraints of the workspace, position, velocity, and acceleration are satisfied. The identification trajectory of each joint of the robot is planned according to a seventh-order polynomial. During the operation of the robot, the position information of each joint and the driving current of each servo motor are collected. The Sobol global sensitivity analysis method is used to perform parameter sensitivity analysis on the linearized dynamic model and identify the parameters. The present invention reduces the number of parameters to be identified and improves the identification efficiency and accuracy.