4 results about "Nonlinear phenomena" patented technology

The invention relates to the field of computer simulation and polymer physics, particularly discloses a simulation method for joint coupling motion of a flexible boundary and an internal active chain based on an annular polymer model, and aims to solve the problem that complex dynamic coupling and nonlinear deformation behaviors between the active chain and the flexible boundary are difficult to really simulate in the prior art. The method comprises the following steps: constructing an annular polymer model formed by connecting inactive particles through chemical bonds so as to characterize a flexible boundary; initializing an active chain model based on boundary geometric constraint, and dynamically aligning driving force and chain segment orientation; adjusting the chain parameters according to the conformation features to generate conformation evolution data; kinetic parameters are extracted to establish a diffusion gradient and volume fraction feedback mechanism, and a bidirectional coupling model is formed by combining the acting force of a local density and velocity field calculation chain on the boundary. According to the technical scheme, non-linear phenomena such as asymmetric collapse, oscillation and bud growth of the boundary can be reproduced in a high-fidelity mode, and the physical authenticity and predictive ability of simulation are remarkably improved.

The invention discloses an electric power system nonlinear participation factor calculation method based on Carleman linearization and modal energy, and belongs to the field of nonlinear system dynamics. According to the technical scheme, the nonlinearity of Taylor high-order expansion is reflected in the increase of a coupling product of a plurality of state variables, and n-order Taylor expansion needs to consider the influence of common disturbance of n state variables on a mode; taking a second order as an example, deriving nonlinear modal energy based on a Carleman linearization method; when xk is equal to 1 and xl is equal to 1, the nonlinear participation factor is equal to two times of modal energy. According to the nonlinear participation factor calculation method, the nonlinear phenomenon of multivariable coupling can be mined. According to the method, under the condition that a nonlinear term brought by Taylor high-order expansion of a differential equation is fully considered, a key influence link is positioned by using a state variable and a mode association degree, and the problem that a traditional linearization method is insufficient in precision and difficult to capture multivariable coupling nonlinear dynamic is solved.

The invention provides a flexible joint mechanical arm tracking control method based on UDE, which is applied to the field of robot intelligence, and comprises the following steps: defining a similar gap lag nonlinear phenomenon based on a gap lag phenomenon of a robot dynamic model; based on the time derivative of the tracking error and the expected error dynamic characteristics of the filtering error, in combination with a robot dynamic model and a class gap lag nonlinear phenomenon, a dynamic equation carrying uncertain items is obtained; carrying out approximation on the uncertain item to obtain an estimated value of the uncertain item; and obtaining a control model of the controller based on uncertainty and disturbance estimation by combining the estimated value of the uncertain item with the kinetic equation carrying the uncertain item. According to the method, modeling errors, parameter uncertainty and hysteresis nonlinear characteristics are collectively called'total disturbance ', so that the common complexity of modeling interference sources one by one in a traditional method is avoided, disturbance can be compensated in real time by simply adjusting bandwidth parameters of the UDE filter, and the control precision is remarkably improved.

This invention discloses a multi-dimensional dynamic prediction method for bypass ratio of a variable cycle engine. Its core lies in establishing a multi-dimensional prediction model and predicting data based on this model: establishing a baseline dynamic sub-model of bypass ratio with respect to area ratio and its rate of change; constructing a physical correction sub-model; and coupling the inlet pressure ratio to the baseline bypass ratio output by the baseline dynamic sub-model to correct the predicted bypass ratio corresponding to the actual inlet pressure ratio ε. This ultimately forms a multi-dimensional prediction model that simultaneously considers area ratio, area ratio rate of change, and inlet pressure ratio. This invention innovatively introduces three dimensions: area ratio AR, area ratio rate of change dAR / dt, and inlet pressure ratio ε, and constructs a prediction model. The obtained model can accurately characterize the inherent hysteresis loop and nonlinear phenomena in the dynamic adjustment of RVABI, overcoming the limitations of steady-state models.