10 results about "Analytical equations" patented technology

This invention relates to the field of eccentric cone feature measurement technology, specifically to a method for measuring and evaluating the eccentric cone features of a triple-eccentric butterfly valve. The method includes: uniformly selecting several measurement sections within the axial range of the point cloud to be measured, and extracting the point cloud subsets corresponding to the measurement sections; performing robust circle fitting on the projection of the point cloud subsets onto the XY plane to obtain a set of section parameters, and calculating the section residuals based on the center coordinates and radius; establishing a linear regression model of the axis center changing with height, solving for the eccentricity and axis inclination slope, and calculating the axis eccentricity distance and axis inclination angle; automatically selecting the optimal generatrix model from a preset model library; performing Fourier series expansion on the residuals of each section, calculating the second-order amplitude, and identifying higher-order distortion terms from the second-order amplitude; and outputting the analytical equation of the cone point cloud based on pose and topography parameters. This invention can accurately identify the nonlinear generatrix features and section distortion of the key sealing surface of a triple-eccentric butterfly valve.

The present application relates to the technical field of traffic safety, and discloses a data processing method and system based on a vehicle and pedestrian lower limb collision analysis model to realize rapid prediction of lower limb injury. The method comprises the following steps: constructing a vehicle and pedestrian lower limb collision analysis model, setting a collision point on a calf mass block when subjected to a collision force brought by a vehicle head, the calf mass block moving along a collision direction under impact load, and establishing a coordinate system with the calf mass point as a system coordinate origin; and in the movement process of the vehicle and pedestrian lower limb collision, the whole lower limb system moves as a projectile relative to the coordinate system and the thigh rotates around the calf, and when the thigh collides with the front edge of the vehicle engine cover, the thigh rotates to a limit position; obtaining an analytical equation of the pedestrian lower limb freedom degree model and an acceleration solving formula of the thigh mass point, and then solving the acceleration of the pedestrian thigh and calf in the collision process according to the vehicle and pedestrian lower limb collision analysis model to perform injury assessment.

This invention discloses a design method for an isostressed arch bridge, relating to the field of bridge engineering design. The method includes: Step 1: Establishing a mathematical model of the rational arch axis of the arch bridge and determining the analytical equation of the rational arch axis of the isostressed arch bridge under dead load; Step 2: Introducing known quantities of the isostressed arch bridge and iteratively solving the analytical equation of the rational arch axis of the isostressed arch bridge using either a method based on the design arch crown stress or a method based on the design arch crown area; Step 3: Determining the design parameters of the isostressed arch bridge based on the solution results of Step 2. This invention overcomes the technical limitations of traditional arch axis design methods, optimizes the stress performance and engineering practicality of arch bridges, and provides an efficient and scientific new solution for the design of long-span arch bridges.

This invention proposes a photovoltaic (PV) system active power reserve point tracking (EPP) control method and tracking control system based on a composite parameter mathematical model. The method includes: establishing a composite parameter mathematical model of the PV system; constructing an analytical equation set based on the composite parameter mathematical model; solving the analytical equation set using currently measured PV operating parameters to obtain real-time parameters such as current environmental irradiance and temperature; determining the maximum power point of the PV system under the current environment; and evaluating the current real-time active power reserve rate of the PV system based on this, thus achieving EPP tracking. This method overcomes the problems of high cost for multi-point, large-scale measurements of irradiance and temperature, and low accuracy for single-point measurements of irradiance and temperature.

A method intended for manufacturing a composite structure for an aircraft. The method includes training a set of artificial neural networks (3.1, 3.2, 3.3) to obtain a composite structure which fulfills certain specification requirements (material properties, shear loads, compression loads, buckling constraints). The neural networks are trained with data obtained from analytical equations and from a finite element model.

The invention provides a three-dimensional magnetic field coil design method suitable for magnetic compensation of a brain magnetic test area. The method comprises the following steps: S1, constructing an analytical model cylindrical coordinate system in the brain magnetic test area; s2, constructing a magnetic field analytical equation; s3, linearly superposing the barrel bottom fan-shaped coil pair and the barrel side saddle-shaped coil to form a radial coil based on a magnetic field analytical equation, and superposing the barrel side annular coil pair to form an axial coil, then optimizing the structural parameters of the radial coil and the axial coil based on an intelligent optimization algorithm, and constructing to obtain three groups of shimming coils and five groups of mutually independent linear gradient coils; and S4, describing interference magnetic field distribution in the brain magnetic test area through a vector spherical harmonic function, and adjusting the magnitude of current flowing in the coil so as to be matched with the interference magnetic field distribution. The method has the beneficial effects that the compensation coil capable of being highly matched with the magnetic field distribution trend of the brain magnetic test area under the interference condition can be designed, and the residual magnetic field in the single-end-opened cylindrical alloy barrel is accurately compensated.

The invention discloses a method for constructing a spatial stress model of a composite beam based on shear hysteresis deflection. The method comprises the following steps of: establishing a basic assumption and displacement mode function of an analytical equation considering the shear hysteresis deflection of the composite beam; establishing a total deflection function of the composite beam based on shear hysteresis deflection under the combined action of axial bending; respectively establishing longitudinal displacement functions of the concrete slab under the action of the bending moment and the axial force; respectively establishing longitudinal displacement functions under different shear lag displacement functions of the upper flange, the web and the lower flange of the box-type steel girder under the action of the bending moment and the axial force; respectively establishing a total potential energy function of the composite beam under the action of bending moment and axial force; respectively establishing control differential equations and boundary conditions under the action of bending moment and axial force; constructing a combined beam space stress model under the axial bending combined action; verifying the correctness of the model; according to the method, the bending deflection + shear hysteresis deflection superposition model of the total deflection is established, the displacement contribution of the shear hysteresis effect is clarified, and the physical significance of a complex mechanical phenomenon is concrete.

The application discloses a design method of a conical face drill tip with controllable lag amount, and belongs to the technical field of metal cutting tools. In view of the problem that the tail root turning point of the existing drill tip relief surface is prone to "warping back" (the lag amount is negative), which leads to interference with the hole bottom, cutting vibration, short tool life and other problems, the application first changes the "lag amount" from an uncontrollable random result into a quantifiable and preset core design parameter. The technical scheme comprises the following steps: establishing a drill tip coordinate system and a relief surface mathematical model; establishing a design parameter and a grinding parameter analytical equation; taking the target lag amount as a core constraint for solving; obtaining a unique grinding parameter through iterative approximation; and performing numerical control machining based on the solved parameter. The application realizes accurate control of the lag amount, eliminates the warping back of the relief surface from the root, and significantly improves the drilling stability, machining quality and tool life, and is particularly suitable for a large-length-diameter-ratio deep hole twist drill.

The application relates to a discrete dynamics modeling method for a space solar panel servo motor system, and belongs to the technical field of dynamics modeling of mechanical and electrical systems of space vehicles. The method aims to solve the problems of mechanical and electrical separation, neglect of flexible load dynamic reaction and lack of external disturbance response mechanism in existing modeling. The technical scheme is as follows: a global explicit analytical equation is established by integrating the electromagnetic characteristics of a permanent magnet synchronous motor, the transmission of a harmonic reducer and the load characteristics of a solar panel, and a response model of the solar panel to space disturbance force is constructed. The model can truly reflect the coupling influence of a large-inertia flexible load on the system, realize high-precision mechanical and electrical joint simulation, quantitatively analyze the action of external disturbance and internal dissipation, and derive low-dimensional explicit dynamics equations, which are convenient for combination with a control system and provide a reliable theoretical model basis for servo control algorithm design.

The invention provides a permanent magnet synchronous generator accurate model construction method based on deep reinforcement learning. According to the method, an electromagnetic field analytic equation, finite element simulation data and a fast convergence Actor-Critic reinforcement learning framework are firstly established, deep reinforcement learning is adopted, and reasonable state space, network structure and the like are designed, so that the limitation of a traditional method technology can be overcome, and a more efficient and more accurate PMSG parameter identification effect is achieved. And continuously feeding back the identified PMSG parameters to the estimation model until the signal difference between the output current of the reference model and the output current of the estimation model is almost zero, thereby obtaining the accurate model of the permanent magnet synchronous generator. Through interactive autonomous learning with the environment, the method has dynamic optimization capability and strong anti-interference performance, and can adapt to variable working condition scenes and realize high-precision control requirements.