51 results about "Nonlinear perturbations" patented technology

The invention discloses an adaptive tracking control method of a multi-mobile-robot system under the condition of attitude unknown. The method includes the following steps of establishing a model for each mobile robot in the multi-mobile-robot system; establishing an error model (as shown in the description) with non-linear disturbance of a follower f and a navigator r, wherein in the multi-mobile-robot system, each mobile robot obtains the information of other mobile robots to carry out non-linear disturbance assessment to obtain the non-linear disturbance estimate value of the mobile robot; establishing an adaptive law (as shown in the description) of non-linear disturbance coefficients; establishing a second-order observer for the trigonometric function of the error angle of the follower and the navigator; and establishing an adaptive control law for the follower based on the observer through the combination of the observer and the adaptive law to perform tracking control of the follower and to make the follower realize the tracking control of the navigator.

The invention discloses a disturbance observer-based underactuated ship path following control method. A virtual ship kinematics model is built; a target reference path is planned; a position time series signal of the target reference path is generated; the position (xd, yd) and the azimuth angle psid of the tracked target at the current time are acquired; the relative position error ze between areal ship and the virtual ship, an LOS heading angle command signals psir of the real ship, and first and second-order derivatives thereof are calculated; a nonlinear disturbance observer is designed;disturbance is estimated; a control law is designed according to a robust adaptive control strategy; a host propulsion control moment command signal tauu and a yaw control moment command signal taurare calculated; and path following control is realized. Dynamic estimation signals for unknown ocean disturbances under severe sea conditions are acquired through a nonlinear disturbance observer method, the control moment of driving propulsion and a steering actuator can be effectively reduced, and the robustness and the economy of underactuated ship path following control under severe sea conditions can be improved.

The invention discloses a speed and current double closed-loop control system and method for a permanent magnet synchronous linear motor. The method comprises the steps of: designing a permanent magnet synchronous linear motor vector control system; designing a fuzzy adaptive sliding-mode speed controller; designing a nonlinear disturbance observation; designing a d-axis fuzzy PID controller; designing a q-axis fuzzy PID controller; obtaining a desired q-axis current reference value as an input of the q-axis fuzzy PID controller according to the designed nonlinear disturbance observer and thedesigned fuzzy adaptive sliding-mode speed controller; setting a d-axis reference current value as 0, and using the id obtained by subtracting park transform from 0 as the input of the d-axis fuzzy PID controller; after the processing by the d-axis fuzzy PID controller and the q-axis fuzzy PID controller, obtaining the ud, uq of the vector control system, and finally outputting the current operating driving voltage of the permanent magnet synchronous linear motor by the anti-park transformation and SVPWM modulation through the vector control and an inverter. The method enhances the robustnessof the system.

The invention proposes a non-fragile distributed fault estimation method based on a sensor network, and the method is a fault estimation method for random nonlinearity and random gain changes of a sensor. The invention relates to the design of a random gain change and random nonlinear time-varying system non-fragile distributed fault estimator. The method introduces a non-fragile distributed fault estimation problem into a nonlinear time-varying system in a sensor network environment at first. The method obtains sufficient conditions through employing the L2 gain theory and the random analysis technology, and guarantees the existing of a needed distributed fault estimator. Compared with a conventional linear fault estimation method, the method can process random uncertainty and random nonlinear phenomena at the same time, and achieves a purpose of nonlinear disturbance resistance.

The invention relates to a method for estimating the state of a networked control system with random uncertainty and delay of distributed sensors, particularly to a method for estimating the state of random uncertainty and delay of distributed sensors. The method solves the problem that the existing method for state estimation can not treat the random uncertainty and the delay of distributed sensors at the same time, so the performance of state estimation is influenced. According to the method of the invention, the influence of random uncertainty and delay of distributed sensors on the performance of state estimation is considered at the same time, and a Lyapunov function is used to fully consider the effective information of the delay. Compared with the existing method for estimating the state of a nonlinear complex dynamic system, the method for state estimation of the invention can be used to treat random uncertainty, delay of distributed sensors and bounded time-varying delay at the same time so as to obtain a method for state estimation on the basis of the solution of a linear matrix inequality; therefore, the purpose of resisting nonlinear perturbation can be achieved. The method is suitable for estimating the state of the nonlinear complex dynamic system.

The invention relates to a multi-group section perturbation method for uncertainty analysis of reactor physics calculation. The multi-group section perturbation method comprises the following steps: (1), on the basis of ENDF/B, making a multi-group section database and a point-by-point section database at different temperatures by using a nuclear database section processing program NJOY, and making the point-by-point section database in a resonant reaction channel at a resonant energy section into an ultra-fine-group database according to the equal rib width; (2), perturbing the point-by-point section database in the energy section corresponding to a certain energy group in a certain reaction channel so as to obtain a perturbed point-by-point section database; (3), strictly transferring perturbation of the point-by-point section database into the multi-group section database by using a linear and nonlinear perturbation transferring method; and (4), reconstructing by adopting a reaction channel section self-consistency principle to obtain a perturbed multi-group section database. According to the invention, the section of a basic reaction channel can be finely sampled; approximate treatment in the multi-group section perturbation process can also be reduced; and thus, a precise multi-group section sample can be obtained.

The invention discloses a combined nonsingular terminal sliding mode control method of a power converter, and relates to a control scheme of combining a sliding mode control method and a disturbance observation technology of a buck converter. According to the invention, first-order nonsingular terminal sliding mode control is enabled to be combined with a nonlinear disturbance observation technology based on an average state model of the buck converter, on-off is controlled by changing the duty ratio of a switching device through adopting a fixed-frequency PWM mode, and thus target voltage output of the buck converter is realized. Provided by the invention is a power converter control method based on combination of a nonsingular terminal sliding mode and the disturbance observation technology so as to solve a problem that traditional sliding mode/PID control is slow in response speed, low in voltage output quality, poor in disturbance resistance and the like. In the control method, the nonsingular terminal sliding mode has the advantages of fast global convergence and high accuracy, and the disturbance observation technology can perform equivalent compensation on the disturbance, so that influences imposed on output voltage by high-frequency vibration are eliminated to a great extent, and thus the anti-disturbance performance of the power converter control system is improved.

The invention relates to a device and a method for linearization of a synthetic aperture radar transmitter. A digital predistortion device is arranged at the front end of the synthetic aperture radar transmitter system, digital signals to be transmitted are subjected to nonlinear disturbance in advance, and a distortion signal is generated; and the distortion signal is complementary with nonlinear characteristics of a power amplifier after passing through the power amplifier, so that a transmitting signal with amplified linearity is acquired. According to the device and the method, the nonlinear correction of the transmitting signal of a synthetic aperture radar can be realized, the linearity of the power amplifier of the radar transmitter is improved, the resolution performance of a synthetic aperture radar transmitter system is improved, and the synthetic aperture radar transmitter system with high linearity is realized.

The invention relates to a sliding mode control method with random nonlinear disturbance. In order to solve the problems that random switching nonlinearity, state time delay and uncertainty cannot beprocessed simultaneously through an existing sliding mode control method, consequently, system output is greatly affected by external disturbance, and the sliding mode control precision is low, the sliding mode control method with random nonlinear disturbance comprises the steps that 1, a dynamic model of a networked control system with the random switching nonlinearity and the bounded state timedelay is established; 2, design of a sliding mode face is conducted on the dynamic model established in the step 1; 3, sliding mode dynamic of the sliding mode face is calculated; 4, the distinguish condition for ensuring the sliding mode dynamic H<infinity> is obtained, and a sliding mode face parameter matrix G is obtained by solving the distinguish condition; and a sliding mode controller is constructed according to the obtained parameter matrix G. Sliding mode control over the networked control system with the random switching nonlinearity and the bounded state time delay is achieved. Thesliding mode control method is used for the field of networked control.

The invention belongs to the technical field of communication security, and particularly relates to an OFDM communication signal physical layer encryption method and device, and the method comprises the steps: carrying out the symbol-by-symbol switching of a chaotic phase sequence initial value through a communication signal transmitting end secret key generation module; generating a dynamic composite chaotic sequence by combining the improved Logistic chaotic mapping and the Chebyshev chaotic mapping, and performing nonlinear disturbance on the composite chaotic sequence to obtain a chaotic sequence for encryption; and mapping the chaotic sequence to an OFDM rotation phase vector to complete physical layer encryption. According to the invention, symbol-by-symbol switching of chaotic sequence initial values is carried out; then, generating a composite chaotic sequence by combining the improved Logistic chaotic mapping and the Chebyshev chaotic mapping; the sequence randomness is improved through nonlinear disturbance, the initial value sensitivity of chaotic mapping is fully utilized, the decoding difficulty is further increased, compared with a traditional chaotic phase encryptionscheme, the operand is greatly reduced, the communication safety performance is greatly enhanced while the encryption chaotic performance is improved, and good application value is achieved.

An apparatus and method for estimating intra-channel nonlinear damage, including: a first determining unit configured to determine a nonlinear phase shift weighting dispersion distribution function of an optical fiber transmission link according to a parameter of the optical fiber transmission link; a segmenting unit configured to segment the nonlinear phase shift weighting dispersion distribution function of the optical fiber transmission link into at least one rectangle; a calculating unit configured to respectively calculate a nonlinear perturbation coefficient of each rectangle in the at least one rectangle, and perform summation on the nonlinear perturbation coefficients of all the rectangles, so as to obtain a nonlinear perturbation coefficient of the optical fiber transmission link; and a second determining unit configured to determine intra-channel nonlinear damage of the optical fiber transmission link according to the nonlinear perturbation coefficient of the optical fiber transmission link.

The invention discloses an anti-interference synchronous sliding mode control method for hybrid type automobile electrophoresis coating conveying mechanism. The method comprises the following steps: firstly, for the hybrid type automobile electrophoresis coating conveying mechanism, using the Lagrangian method to create a kinetic model containing the total disturbance term and performing motion trajectory planning to the mechanism; then, using the detection result from a decoder to calculate and obtain the tracking errors of the active joints and defining a coupling error; after that, based on the coupling error, designing a cross coupling synchronous sliding mode controller; based on the kinetic model, designing a non-linear disturbance observer; further, in combination with the cross coupling synchronous sliding mode controller and the non-linear disturbance observer, developing an anti-interference synchronous sliding mode controller; and finally, through the software programming, realizing the anti-interference synchronous sliding mode control to the conveying mechanism. According to the invention, not only the synchronous performance of the conveying system is increased; but also the robustness and the anti-interference capability of the system are improved. In addition, the problems with the jittering in sliding mode control and the saturation of the execution device of the control system can be inhibited.

The invention provides a design method of a position and attitude observer for an airborne parallel platform. According to the design method of the position and attitude observer for the airborne parallel platform, a six-degree-of-freedom parallel machine platform serves as the airborne platform, the position and attitude of a fixed end of the platform dynamically changes along with a body, and the position and attitude of a workbench which is controlled by six parallel extensible rods and universal hinges is always located in the horizontal state; the actual length of the extensible rods is measured through a sensor and the position and attitude of the platform is estimated through a nonlinear observer; a measurement error of the length of the extensible rods serves as an input signal of position and attitude estimation through a state observer; the nonlinear observer is transformed into a linear observer with a nonlinear perturbation through differential homeomorphism for calculation; meanwhile the estimation of a gain matrix is achieved by an automatic differential technology and accordingly the solving speed of the gain matrix is greatly improved.

A method and system for correcting the effect of intensity fluctuations of the transmitted light in an absorption spectroscopy system used for the detection or measurement of chemical species in a medium, whereby one or more modulation bursts are imposed onto a light beam that passes through the medium. This burst signal may be obtained by modulating the bias current of a tunable diode laser, and the modulation burst signal may be optimally at the second harmonic of the modulation frequency of a wavelength modulated beam to allow usage of the same signal path processing used for the spectroscopic detection of the measurand for a second harmonic detection system. The burst signal can be controlled using a smooth window function to minimise the effects of non-linear perturbations that are inherent in tunable diode laser wavelength modulation spectroscopy systems, of optical interference fringes (etalons) and of the residual light absorption by background chemical species or the measurand at the wavelength coinciding with the modulation burst.

Embodiments of the present disclosure provide an estimation apparatus and method for nonlinear distortion and a receiver. The estimation method for nonlinear distortion includes: sampling a band-limited analog signal to obtain a sampling sequence; calculating a nonlinear perturbation coefficient in nonlinear distortion estimation based on a Nyquist pulse; calculating a nonlinear perturbation term superimposed on a signal by using the nonlinear perturbation coefficient and the sampling sequence; and calculating a nonlinear distortion waveform by using the nonlinear perturbation term. With the embodiments of the present disclosure, not only any modulation formats are compatible, but also advantages of high precision and good adaptability may be achieved.

The invention discloses a time-varying event trigger filtering method with data loss under an unknown probability condition, and belongs to the field of control systems. An existing filtering method cannot process data loss with unknown probability, random nonlinearity and an event triggering mechanism at the same time, and the performance of a filter is affected. The method comprises the following steps: establishing a dynamic model of a time-varying system with an unknown probability of data loss, random nonlinearity and an event triggering mechanism; Designing a filter according to the established time-varying system dynamic model; Calculating the upper bound of the one-step prediction error covariance matrix of the filter; Calculating a filtering gain matrix; Calculating the upper bound of the filtering error covariance matrix; And substituting the obtained filtering gain matrix into a designed filter to obtain a data loss, random nonlinearity and event trigger mechanism filter with unknown probability. The method can simultaneously process data packet loss with unknown probability, random nonlinearity and an event trigger mechanism, achieves the purpose of nonlinear disturbance, and is easy to solve and implement.

The invention relates to a wind power plant power prediction method considering an atmospheric disturbance effect. The method comprises the following steps of regarding an atmosphere nonlinear Lorenz system as a disturbance model, defining atmosphere nonlinear disturbance variables to eliminate nonlinear factors contained in original air speed data, and optimizing the input of a power prediction model, so that the wind power prediction with higher accuracy can be realized. According to the wind power plant power prediction method considering the atmospheric disturbance effect, on the basis of a conventional power prediction method, a power prediction disturbance formula is utilized to carry out nonlinear disturbance correction on a wind speed prediction result, and the influence of some nonlinear disturbance factors existing in original wind speed on the prediction result is eliminated, so that the aim of accurately predicting wind power is achieved. The experiment result shows that according to the method, the prediction accuracy of wind energy can be greatly improved, and the development of wind power industry is greatly promoted.

The invention discloses a load feedforward control method of a dual active bridge DC/DC converter. The control method comprises the steps of controlling the dual active bridge DC/DC converter by a voltage controller in a phase shifting control mode after the dual active bridge DC/DC converter is started; starting a non-linear disturbance observer to estimate the load current of the dual active bridge DC/DC converter; enabling the estimated load current to be summed with the output of the voltage controller to obtain an output current reference value of the dual active bridge DC/DC converter; and calculating the output of a current controller based on the output current reference value of the dual active bridge DC/DC converter, and converting the output current reference value of the dual active bridge DC/DC converter into a phase shifting angle to be used as a control switch of a switch in the dual active bridge DC/DC converter.

The embodiment of the invention provides a feedback-type energy transmission optical fiber and an optical fiber energy transmission system and device. The feedback-type energy transmission optical fiber comprises a sensing feedback optical fiber core and at least one set of energy transmission optical fiber cores, wherein the energy transmission optical fiber cores are used for transmitting optical energy, the sensing feedback optical fiber core is used for transmitting feedback information, and the feedback information is used for representing nonlinear disturbance generated by the energy transmission optical fiber cores in the process of transmitting the optical energy, thereby realizing the feedback for the nonlinear disturbance generated in the optical fiber energy transmission process, and thus laying a foundation for taking corresponding measures in allusion to the nonlinear disturbance to reduce influences imposed on the transmission efficiency of high-power laser by the non-linear effect in the energy transmission optical fiber.

The invention discloses a construction method for an intelligent dynamic anti-interference controller of a new energy automobile driving motor. The construction method comprises the following steps: collecting an actual current and a reference current of a d-q axis, and establishing a driving motor system 18 through internal module calculation and coordinate transformation; building a driving motor system dynamics model; establishing a torque calculation controller 31, estimating an angle error of the driving motor system dynamics model through the torque calculation controller 31, and introducing a nonlinear disturbance observer 32 to identify uncertain disturbance; establishing a dynamic surface controller; and coping with dynamic uncertainty and uncertain disturbance by adopting recursive wavelet Elman neural network control, and constructing a robust controller for control. Compared with the prior art, the cost is relatively low, the feasibility is relatively high, and the anti-interference performance is relatively good; and the method is easy to implement in engineering.

The invention discloses a numerical method for predicting jet noise of a single-nozzle carrier rocket. The numerical method comprises the steps: firstly building a single-nozzle carrier rocket three-dimensional model, and carrying out the mesh generation of the single-nozzle carrier rocket three-dimensional model through a partitioning structured mesh method; thirdly, calculating a gas jet steady-state flow field of the single-nozzle carrier rocket to obtain initial sound field information; obtaining initial sound field information from the steady-state flow field, and reconstructing a turbulence pulsation signal by adopting a nonlinear disturbance equation; and finally, based on an FW-H equation of an acoustic comparison method, collecting noise information of a far-field receiving point,and outputting a frequency spectrum curve of the noise receiving point. According to the numerical method, the grid number is reduced and the calculation efficiency is improved while the calculationprecision is ensured.

The invention discloses a specified performance parameter estimation-based self-adaptive control method, which relates to a specified performance parameter estimation-based self-adaptive control method for a motor servo system, and belongs to the technical field of electromechanical control. The method comprises the following implementing steps: establishing a model containing a nonlinear friction and disturbance motor servo system; designing a performance specified performance function with a rate of convergence, a maximum overshoot and a stable tracking error; adopting a high order neural network to approach to nonlinear disturbance of the system, according to the established model containing the nonlinear friction and disturbance motor servo system, the specified performance function and a parameter estimation error-based parameter estimation method, designing a finite time self-adaptive controller u, and controlling the motor servo system according to the controller u. The method realizes the parameter estimation on the motor servo system, overcomes nonlinear influences such as friction, disturbance and extra disturbance, and further improves the transient performance and stable tracking performance of the motor servo system.