45 results about "Mechanical equation" patented technology

The invention provides a microgrid and microsource control method based on a virtual synchronous electric generator. The method comprises the following steps of building a mechanical equation and an electromagnetic equation of the virtual synchronous electric generator, carrying out microsource active control through active adjustment of the virtual synchronous electric generator, carrying out microsource reactive control through reactive adjustment of the virtual synchronous electric generator and achieving seamless switching between different operating modes of a microgrid. The microgrid and microsource control method based on the virtual synchronous electric generator has the active and reactive adjustment capacity similar to that of the synchronous electric generator, can simulate the inertia and the damping characteristic of the synchronous electric generator, can overcome the impact on a power grid from inertialessness of a traditional grid-connected inverter, and can effectively improve the capacity of the power grid to accept the renewable energy sources.

The present invention relates to a control algorithm constructing device that constructs a control algorithm controlling the motion of a robot, and a controller that controls the motion of the robot in accordance with the constructed control algorithm, with the purpose of reducing the cost and time taken to create the control algorithm as compared with the conventional method such as an MZP method to solve a mechanical equation, in which the control algorithm is constructed by a recurrent neural network (RNN) including a neuron generating an output with an analogue lag with respect to an input, the coefficients of the RNN are determined in succession from the term of lower degree to the term of higher degree.

The invention discloses an overrunning virtual synchronous generator (VSG+) method with rotary inertia and damping self-optimization-trending. The method comprises the following steps: step one, a mechanical equation and an electromagnetic equation of a virtual synchronous generator (VSG) are established; step two, the rotary inertia J and damping D in a VSG model are increased as |delta f| is increased, wherein delta f is an absolute value of a difference between a power network rated frequency and the actual frequency of the VSG; and step three, according to self-adjustment of the rotary inertia J and the damping D, closed-loop control is performed on the |delta f|, and finally, grid connection of a distributed photovoltaic power generation system is realized. According to the VSG+ method with the rotary inertia and damping self-optimization-trending, provided by the invention, the rotary inertia J and the damping D in the VSG are adaptively adjusted as the |delta f| changes, the rotary inertia J and the damping D after adjustment then perform feedback regulation on the |delta f|, and finally, zero impact during grid connection of photovoltaic inverters is realized, such that the acceptance capability of a power network for the distributed photovoltaic power generation system is improved.

The invention discloses a virtual impedance voltage converter-based control method of a virtual synchronous motor. Output voltage and current of a voltage converter is controlled to have the characteristic of a synchronous motor through electric and mechanical main parts of the virtual synchronous motor, wherein the electric part comprises a novel virtual impedance simulation algorithm, a conventional converter current inner ring and a modulation strategy and the mechanical part comprises a power calculating module, a rotor mechanical equation and a virtual damping module. The virtual impedance voltage converter-based control method of the virtual synchronous motor can be used for simulating winding impedance without introducing a differential term of current output by the converter, so that the influence on impedance simulation by an extra low pass filter is overcome, and the current inner ring control of a parallel converter is not sacrificed, and therefore, alternating current is controlled, and the converter has the capacity of preventing current fluctuation, overcurrent and even impact without quick current inner ring control. A silent pole motor and a non-salient pole motor can be simultaneously simulated.

The invention discloses an electric car power-grid voltage compensation method based on a virtual synchronous generator algorithm, and the method comprises the following steps: 1), employing the virtual synchronous generator algorithm for an electric car grid-connected interface, and carrying out the droop control based on P-f and Q-V; 2), obtaining the output frequency w and phase angle theta of the grid-connected interface through simulating a mechanical equation of a synchronous generator; 3), employing a voltage and current double-closed-loop control strategy based on the dp coordinate system for an electrical equation part; 4), adding virtual impedance control at the electrical equation part, wherein the virtual impedance comprises constant virtual impedance and transient virtual resistance; obtaining virtual voltage drop, and taking a voltage instruction E obtained at step 1) as a voltage ring d-axis instruction ed, wherein eq is equal to zero; respectively calculating the differences between the ed and eq and the virtual voltage drops vvd and vvq, and obtaining a voltage ring output voltage instruction (shown in the description); 5), obtaining a dq-axis modulation signal of the grid-connected interface through the output of a current ring at step 3), and obtaining a switching control signal of a converter switching network through coordinate conversion and PWM, so as to drive a switching network.

The invention discloses a fuzzy-control-based virtual synchronous motor's virtual inertia adaptive regulation method and a frequency control method. The method comprises the following steps: targeted to the micro source of a currently available micro power grid utilizing the virtual synchronous motor control technology for inversion output, using the output frequency error and the error variation rate of the micro source as the fuzzy output; and based on a two-dimensional fuzzy principle, dynamically adjusting the virtual inertia time constant. The invention further provides a frequency control method, comprising: in combination of the mechanical equation of a virtual synchronous motor, adjusting the output frequency of the virtual synchronous motor to strike a balance between the frequency support and dynamic response in its involvement in the concrete frequency adjusting process, to reduce load switching and the frequency fluctuation rising from micro source grid connecting and to ensure the stable frequency and rapid response of the micro power grid under the islanding state.

The invention discloses a soft tissue deformation simulation method based on a roll nonlinear anisotropic mass spring model, which comprises the following steps: 1) constructing a mass spring model, and determining initial elastic parameters of that mass spring model by a finite element method; 2) setting spring parameters in the deformation process according to the stress and strain relationshipof the muscle tissue; 3) parameterize describing that anisotropic characteristic of the soft tissue by constructing a mechanical equation of the spring; 4) constructing that dynamic equation of the mass spring model and solving it. The invention has the beneficial effect that the setting of the spring parameter in the mass spring model is solved, the anisotropy is parameterized, and an improved Euler algorithm is adopted in solving the dynamic equation of the mass spring model.

The invention discloses a corrective natural fracture hydraulic fracturing in-situ stress measurement method. According to the method, a mechanical equation is established for shear stress widely existing in a natural fracture surface, and an in-situ stress tensor is obtained through inversion by searching for a natural fracture surface friction coefficient by use of a least square method and a computer program trial and error method. Through the method provided by the invention, the number of natural fractures needed by a conventional natural fracture hydraulic fracturing in-situ stress measurement method is substantially reduced, many hypothesis conditions set for an in-situ stress field during application of the natural fracture hydraulic fracturing in-situ stress measurement method are eliminated, the application difficulty of the natural fracture hydraulic fracturing in-situ stress measurement method is lowered, and the accuracy of the method is improved.

The invention provides an energy storage inverter virtual synchronization method and system for adaptive optimization of power grid strength. The method includes data acquisition, power calculation, output calculation of a virtual speed governor, output calculation of a rotor mechanical equation, power grid impedance calculation, damping value spline interpolation fitting and parameter updating. Improvement is made on the virtual damping link. By introducing differential into the virtual damping link, the virtual damping has no effect on the virtual difference coefficient, and the steady stateerror of the primary frequency modulation of a virtual synchronous machine is eliminated. Meanwhile, a first-order inertia link is introduced to improve the stability of the system. Adaptive parameter optimization control is carried out on the virtual damping link. The impedance of the power grid is detected online by harmonic injection, and the parameters of the damping link are adjusted onlineaccording to the detected impedance of the power grid and an adaptive formula, so that the virtual synchronous machine can have better response characteristic before and after the change of power gridstrength.

A second-order sliding mode control method for magnetically suspended switched reluctance motor is disclosed in the invention. The speed loop adopts the second-order sliding mode speed controller based on the superscrew algorithm, The reference torque is obtained by selecting the speed error to construct the sliding mode surface and combining with the mechanical equation of the maglev switched reluctance motor. The displacement loop adopts the second-order sliding mode displacement controller based on the improved superscrew algorithm, A high order error derivative of displacement is introduced to make the superhelix algorithm suitable for second order systems, The reference levitation force is obtained by improving the superscrew algorithm combined with linear compensation term. The invention adopts a second-order sliding mode speed controller based on a superscrew algorithm and a second-order sliding mode displacement controller based on an improved superscrew algorithm, The speed control precision and rotor suspension precision of SRM are improved, the problems of speed buffeting and displacement buffeting are solved, and the system has strong robustness to uncertain disturbance, which is easy to be realized in engineering.

A method for three-dimensional crack propagation, morphology, and initiation suited to directed surfaces, or stacks of directed surfaces. An external damage measure and failure criteria can be incorporated, as well as a rule-based crack direction and morphology capability. This method is ideal for laminated composites. Further, the use of external damage and failure, and rule-based crack propagation, this method is ideal for multi-scale modeling and use in applications where knowledge and rules are necessary or desirable for guiding, driving, or influencing failure modes, directions, or other situations that are not directly incorporated into the governing mechanical equations.

The invention belongs to the technical field of instability risk decision of a dam in water conservancy and hydropower engineering and provides a novel method for calculating united sliding-resistant stability of the dam and a force-resisting mountain body in order to overcome defects in calculation and analysis of the combined action of the dam and the force-resisting mountain body in the traditional technology. According to the method, the sliding-resistant stability of the concrete gravity dam under the action of the force-resisting mountain body is quantified accurately, reasonably and efficiently, and important basis is provided for structural design, reinforcement, optimization, safety evaluation, risk control and the like of dam sliding resistance assisted with downstream resistance blocks. The method comprises following steps: a, force analysis of the combined action of the dam and the force-resisting mountain body is performed; b, a mechanical equation for the united sliding-resistant stability of the dam and the force-resisting mountain body is established; c, mathematical analysis and mechanical assumption are performed on the equation; d, a limit equilibrium principle is adopted to solve a sliding-resistant stability safety factor. The calculating method is utilized to evaluate dam foundation stability, a process is simple and easy to understand, and the evaluation standard is adaptive to the specifications.

A system for controlling actuation of an electromagnetic actuator includes an actuator having an electrical coil, a magnetic core, and an armature. A controllable drive circuit is responsive to an electric power flow signal for driving current through the electrical coil to actuate the armature. A control module includes an armature motion observer configured to determine an armature motion parameter in the actuator based upon a magnetic flux within the actuator and a predetermined mechanical equation of motion corresponding to the actuator and adapt the electric power flow signal based on the armature motion parameter.

The invention provides a numerical simulation method for generating a three-dimensional damaged pattern. The method comprises the steps of establishing a three-dimensional geometric model for an object described in a three-dimensional damaged pattern, dissecting mesoscopic grids, setting a boundary condition, an initial condition and material parameters for the numerical simulation, selecting a yield surface with angular points, considering a strength-softening constitutive relationship and a non-associated flow rule, conducting the numerical simulation on the geometric model based on the finite-element dynamic relaxation method to get a solution, and outputting a three-dimensional damaged pattern. In this way, the three-dimensional damaged pattern can be generated directly based on a mechanical equation without the need of pre-assuming any physical mechanism. The above method provided in the invention is used for directly generating three-dimensional damaged patterns. Three-dimensional damaged patterns, generated based on the above method, can better reflect the actual damage situations of materials. Therefore, the mechanical performances of materials can be reflected more intuitively and more truly.

The invention provides a method for determining buckling load-end shrinkage curves of deck longitudinal beam columns supported by cantilever crossbeams, and belongs to the technical field of ship structural engineering. The method for determining buckling load-end shrinkage curves of deck longitudinal beam columns supported by cantilever crossbeams comprises the following steps of: 1, establishing a deck longitudinal beam column instability mechanical model after large-scale impact; 2, establishing a cantilever crossbeam mechanical equation and obtaining a lowest-order frequency formula; 3, establishing a cantilever crossbeam torsional rigidity calculation model and determining a torsional rigidity; 4, determining a support rigidity, for a deck longitudinal beam, of a crossbeam; 5, determining a longitudinal beam column buckling curve and a buckling critical load; and 6, determining a critical load-end shrinkage curve of the longitudinal beam column. The method provided by the invention is a theoretical method for rapidly obtaining the buckling load-end shrinkage curves of longitudinal beam columns supported by cantilever crossbeams after large-scale impact damage, so that the calculation is improved; and compared with a nonlinear finite element method, the method has the advantages of shortening the calculation time and improving the efficiency.

The invention provides a method, based on a two-dimensional flutter stability limit diagraph, for determining a stable processing technological parameter diagraph used for engineering. The method is characterized by selecting modal vibration modes of workpiece processing points on the limit diagraph as main parameters, using a weighted membership degree and a curve smoothness degree as optimization constraint conditions and providing engineered application curves and function expression equations of a high-speed cut thin-walled piece. The method comprises the steps of: in a stable processing technological parameter curve in an application interval of a main shaft rotation speed in the limit diagraph, eliminating first and second order modal frequency flutters of a technology system at a cutting depth corresponding to the main shaft rotation speed according to a multiple of the membership degree, and correcting the cutting depth based on the coupling between the first and second order modal frequency flutters of the processing system; carrying out secondary correction on the stable processing technological parameter curve after the correction; carrying out fitting and extraction of specific functions on an established engineered curve; and determining stable processing mechanical equations and the stable processing technological parameter diagraph used for engineering. The method has the advantages that the high-efficiency flutter-free milling parameters are selected, the production period of a product is shortened, and the integral processing efficiency of a high-speed milling system is improved.

The invention provides a bolt connection cylindrical shell structure dynamic characteristic calculation and analysis method, and belongs to the technical field of mechanical dynamics. The method comprises the following steps: establishing a cylindrical shell energy equation according to a plate-shell theory; establishing a load excitation equation according to the external load condition; establishing a bolt connection mechanical equation according to the bolt connection characteristics; solving bolt connection equivalent stiffness and equivalent damping according to first-order Fourier decomposition; accurately expressing different load characteristics through component force in each vibration displacement direction; obtaining a forced vibration differential equation of the bolt connection cylindrical shell structure through a Lagrange equation; and solving the dynamic characteristics of the bolted connection cylindrical shell structure by applying an incremental harmonic balance method. The method starts from the establishment of a bolted connection equivalent mechanical model, is applied to a cylindrical shell structure, achieves the solving of the vibration response according to the demands of different actual working conditions, simplifies the modeling and calculation process, is high in precision, is high in universality, and the like.

The invention provides a position-free control system for compensating a back electromotive force constant of a brushless direct-current motor. The position-free control system comprises a speed PI controller, a current PI controller, a position vector controller, a rotor current detection module, a position error detection module, a back electromotive force calculation module and a back electromotive force constant compensation module. According to the system, a stator voltage equation is combined with a rotor mechanical equation, so that the estimation of back electromotive force is more accurate.

The invention discloses a vascular blood flow simulation method based on a mechanical equation and a related device. The method comprises the steps of obtaining characteristic data of a blood vessel;constructing a three-dimensional cavity model and a blood vessel wall model of the blood vessel according to the characteristic data, and defining a calculation area; discretizing the calculation areato generate an initial grid for describing the calculation area; carrying out encryption processing on the initial grid to generate a fine grid calculation area; carrying out roughening processing onthe initial grid to generate a coarse grid calculation area; calculating the coarse grid calculation area to obtain a final blood flow parameter of each coarse grid point in the coarse grid calculation area; generating an initial blood flow parameter of each fine grid point in the fine grid calculation area according to the final blood flow parameter of each coarse grid point; and based on the initial blood flow parameter of each fine grid point, calculating the fine grid calculation area to obtain the final blood flow parameter of each fine grid point in the fine grid calculation area. Accurate and efficient simulation of blood flow in the blood vessel can be realized.

The invention discloses a dynamic constraint combined human body inertia parameter identification method. The human body is simplified into a multi-segment rigid model composed of multiple segments ofrigid bodies, and a dynamic equation of the multi-segment rigid model is established; and human body motion sampling data is collected via a motion capturing system and a ground counterforce detection system, a first-step identification human body inertia parameter is obtained via a first simplified mechanical equation, a second-step identification human body inertia parameter is obtained by introducing a basic physical constraint, and a third-step identification human body inertia parameter is obtained via a second simplified mechanical equation, and finally, the inertia parameter whose second-order norm is minimal is selected as a human body inertia parameter identification optimization result. Multiple constraints are introduced, so that a calculation process of human body inertia parameter identification is clear and can be programmed easily; the dynamic equation is simplified to measure the joint moment directly, a joint moment estimated value constraint is introduced for optimization, and the accuracy of an inertia parameter identification result is improved.

The invention discloses a chip surface contact pressure calculation method and a variable-scale manufacturability design method. The calculation method comprises the steps of performing grid division on a wafer surface where a chip is to obtain a plurality of first grids; calculating a contact pressure of each first grid by utilizing a contact mechanical equation set to obtain contact pressure distribution of the wafer surface, and marking the contact pressure distribution as first contact pressure distribution; dividing each first grid into a plurality of second grids; calculating a contact pressure of each second grid by utilizing the contact mechanical equation set to obtain contact pressure distribution in each first grid, and marking the contact pressure distribution as second contact pressure distribution; and according to the line width in each second grid, calculating contact pressure distribution in each second grid, marking the contact pressure distribution as third contact pressure distribution, and obtaining contact pressure distribution of the chip surface. According to the chip surface contact pressure calculation method provided by the invention, the calculation efficiency and the calculation precision can be considered simultaneously, thereby providing premise and guarantee for manufacturability design optimization.