36 results about "Stability theorem" patented technology

The invention discloses a composite anti-interference controller comprising measurement and input time delay for a flexible spacecraft and relates to attitude control of the flexible spacecraft under time-varying delay and multi-source interference. The method comprises the following steps of: establishing a dynamical model of the flexible spacecraft; constructing a composite anti-interference controller comprising measurement and input time delay, estimating and performing feed-forward compensation on the anti-interference controller according to an interference observer comprising measurement time delay with interference design caused by vibration of flexible accessories, and designing a state feedback H8 controller to suppress the anti-interference controller according to the norm-bounded interference; designing gain of the interference observer to guarantee the stability of an interference estimated error dead time delay equation according to the 3 / 2 stability theorem; and finally, designing the gain of the state feedback H8 controller for a composite control system comprising measurement and input time delay based on a convex optimization algorithm, so that the system is stabilized, and a certain H8 performance is met. The composite anti-interference controller has the advantages of high interference resistance, convenience in design and the like and can be used for the attitude control of the flexible spacecraft comprising measurement and input time delay.

The invention discloses an LMI linear inequality-based micro gyroscope H-infinity control method. The method includes the following steps that: S101, the ideal dynamic model of a micro gyroscope is established; S104, a dimensionless vector model of the micro gyroscope is established; S103, a robust adaptive neural network H-infinity controller is designed based on an linear inequality according to the ideal dynamic model and the dimensionless vector model; and S104, a neural network weight adaptive law is designed based on based on the lyapnov stability theorem, so that the established controller can be updated online. The LMI linear inequality-based micro gyroscope H-infinity control method of the invention has the advantages of high robustness and high stability.

The invention belongs to the technical field of network security, and in particular relates to a network defense strategy selection method based on a random evolutionary game model. The network defense strategy selection method based on the random evolutionary game model comprises the steps of: constructing an asymmetrical network attack-defense random evolutionary game model based on a random power system; with the help of Gaussian white noise, obtaining a network attack-defense random evolutionary game system by adopting Ito random differential equation; performing numerical solution of the network attack-defense random evolutionary game system by adopting an Milstein method, so that an attack-defense evolutionary equilibrium solution is obtained; and, for the attack-defense evolutionary equilibrium solution, performing stability analysis of strategy selection states of both attack and defense sides according to the stability theorem of the solution of the random differential equation, and outputting a network security defense strategy in the equilibrium solution. By means of the network defense strategy selection method based on the random evolutionary game model disclosed by the invention, the problems, such as a problem that the traditional game model applied to network defense strategy selection is not accurate enough, can be solved; the random dynamic evolutionary process among boundedly rational attack and defense decision makers can be analyzed more accurately; the security defense strategy selection practicability is improved; and the network defense strategy selection method has the important guiding significance for the network security defense technology.

The invention discloses a model-free quadrotor unmanned aerial vehicle trajectory tracking controller based on RPD-SMC and RISE, and a method, and a RPD-SMC controller is designed. The controller combines advantages of a proportional differential-sliding mode controller (PD-SMC) and online estimation capability of a radial basis function neural network (RBFNN) on arbitrary function. Through introducing self-adaptive RBFNN feedforward, disturbance and unknown dynamic conditions are estimated and compensated, so that selection of control parameters of the PD-SMC is more rational, to achieve objectives of reducing controlling quantity and saving electric energy. Aimed at an inner-loop control system, an error symbol integral (RISE) controller based on robustness is designed. The RISE controller can ensure rapid convergence of a posture angle and has strong robustness on disturbance. Beneficial effects are that the lyapunov theorem of stability proves stability of the inner-loop and outer-loop systems, and simulation experiment results prove that the controller has validity.

The invention discloses an aircraft power system average value model and large-disturbance stability domain constructing method. The method comprises the following steps: establishing an aircraft power system average value model, wherein the equivalent circuit of the aircraft power system average value model comprises a power supply, a DC-side inductor, a DC-side resistor, a diode, a DC-side filter inductor, a DC-side filter resistor, and a load which are successively connected in series to form a closed loop, wherein the load is connected in parallel with a DC-side filter capacitor; constructing a stability domain, determining the mixed potential function of the system based on the aircraft power system average value model, constructing the Lyapunov energy function of the system, and calculating the critical energy of the system in combination with amixed potential function stability theorem, and determining the stability domain of the system. The invention provides an analysis tool for the modeling and stability analysis of a multi-electric aircraft power system, and can provide an evaluation method for system parameter design and optimization, and is suitable for multi-electric aircraft power system analysis and power electronic modeling field.

The invention discloses a single population balance system and method based on constructing a positive Liapunov function. The method of the invention follows the steps: Step 1. Construct a mathematical model of the population; Step 2. Calculate the equilibrium point that the population tends to; Step 3. According to the stability of the equilibrium point, construct the fixed Liapunov function; Step 4. According to the stability of the fixed Liapunov function, analyze and optimize with the equilibrium point as the limit; Step 5. The population density tends to the equilibrium point to obtain the area of ​​species balance . In order to explore the stability of a single species, the present invention constructs a fixed Liapunov function through mathematical modeling of a density-limited single species. According to the global asymptotic stability theorem, the equilibrium point is used as an asymptotic line analysis and optimization to solve the single species The area tends to ecological balance, and then numerical simulation verifies the correctness of the method.

The invention provides an H8 fault tolerance control method for a networked linear parameter variation system with time variation and time delay, and belongs to the field of networked linear parametervariation system control. The method takes the situations that a linear parameter variation system has network time variation and time delay and a sensor and an executor break down simultaneously inaccount, firstly a method of free-weighting matrix is used to establish a Lyapunov function for processing the time variation and time delay to obtain sufficient conditions of closed-loop fault tolerance control system stability, then a Lyapunov theorem of stability and a linear matrix inequality analysis method are used to obtain sufficient conditions of H8 fault tolerance controller existence, lastly an approximate primary function and a gridding technology are used to approximate a solving problem of an infinite dimensional linear matrix inequality system with a solving problem of a finitedimensional linear matrix inequality system, a Matlab LMI toolkit is used for solution, and a gain matrix of an H8 fault tolerance controller is provided. The H8 fault tolerance control method for thenetworked linear parameter variation system with the time variation and the time delay reduces the conservatism of the H8 fault tolerance controller.

The invention discloses a method for identifying the rotor time constant of an induction motor, which comprises the steps of: 1. Constructing the ESO model of the rotor flux linkage of the induction motor; 2. Constructing the current model of the induction motor; ;4. Determination of the rotor time constant of the induction motor: with the rotor flux ESO model as the reference model and the current model as the adjustable model, under the action of the adaptive law, the reciprocal of the rotor time constant is estimated And send it into the current model, adjust the output flux value of the current model in real time, so that the output flux value of the current model can keep up with the flux output of the rotor flux ESO model, when the rotor flux ESO model and the current model output the rotor flux value equal, Determine the output value as the induction motor rotor time constant. The invention has accurate rotor time constant identification, can improve the precision of magnetic field orientation and speed tracking of the induction motor vector control system, has strong robustness to motor load disturbance, and has high motor speed tracking precision.