30 results about "Lyapunov theorem" patented technology

Based on a neural network technology and an instruction filtering inversion method, the invention discloses a robust fault tolerance control system design structure based on instruction filtering inversion. Firstly, a mathematical model of an NSV attitude control system is given out, uncertainties and external disturbance caused by modeling errors are considered based on the mathematical model, a state equation of the NSV attitude control system under the fault of a control surface is also considered. The method mainly includes the two design parts including design of an auxiliary system and design of a controller based on the auxiliary system. The auxiliary system is introduced into the neural network to ensure robustness of the auxiliary system, and stability of a closed-loop system is strictly proved through Lyapunov theorem. Meanwhile, simulation is carried out on an attitude control system of a corresponding air vehicle, and a result shows that the method enables the uncertain flight control system with the external disturbance to have the ideal fault tolerance tracking performance under damage to the control surface.

The invention provides a coupling enhancing non-linear PD-type sliding mode controller for a bridge crane system, and a method. The designed controller is composed of a PD control part and an SMC control part. The SMC control part is used for constructing a frame of the controller. Quite high robustness is achieved aiming at an indeterminate model, different and indeterminate system parameters andexternal disturbance of a system. The PD control part is used for stably controlling the system. In addition, a generalized function is introduced, the coupling relation among trolley movement, lifting hook swinging and load swinging is enhanced, and thus the transient control property of the system is improved. By utilizing the Lyapunov theorem and Schur complement, it is proved that the asymptotic stability and convergence of the system can still be ensured through the provided control method even if the model and the system parameters are indeterminate and external disturbance exists. Thesimulation result shows the correctness of the provided control method and the excellent control property.

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 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.

A disturbance compensation based RLV (reusable launch vehicle) approach landing guidance law acquisition method includes: firstly, calculating a height deviation and a lateral distance deviation according to an RLV approach landing nominal trajectory; secondly, using the Lyapunov theorem to obtain an anticipated flight path angle and a direction angle, namely virtual control laws according to a tracking deviation of the nominal trajectory; finally, adopting a backstepping design method to provide a guidance acquisition method capable of guaranteeing stability of a guidance loop. In a design process, an uncertainty upper bound of the guidance loop is obtained by analysis of aerodynamic data and inhibited by introduction of a compensation term, and consequently a guiding system has asymptotic stability in uncertainty of disturbance and the like. By adoption of the disturbance compensation based RLV approach landing guidance law acquisition method, influences of uncertainty on the RLV guiding system can be effectively overcome, and accordingly guiding precision is improved.

The invention relates to linear servo position tracking control based on a linear matrix inequality and sliding mode control. Control designing is performed through using a mechanical subsystem and anelectrical subsystem as a whole member. A complicated problem which is hard to solve is converted to a relatively easy linear matrix inequality (LMI) problem. An Lyapunov theory is used for proving system stability. An MATLAB-LMI toolset is used for calculating a result. Offline studying is performed on periodical linear factors such as end effect and friction by means of a neural network thrustobserver for ensuring system real-time performance, and then the factors are applied to the system for observing load disturbance. Finally the invention realizes a purpose of realizing high robust tracking performance of the system.

The invention relates to a sliding mode control method of an input saturated spacecraft attitude terminal, belonging to the technical field of spacecraft attitude adjustment. According to the method,two non-unwinding robust finite-time control methods are designed for a spacecraft and are a compensation known bounded method and a hyperbola tangent function and auxiliary system control method. According to the compensation known bounded method, known bounded external disturbances can be compensated, and external disturbance and input saturation problems can be solved by using the hyperbola tangent function and auxiliary system control method. The Lyapunov theorem is used to prove the finite-time stability and asymptotic stability of an entire closed-loop system. A simulation result shows that a controller can make the spacecraft to track a time-varying reference attitude signal within a limited time.

The invention relates to a stability control method of a mill roll system under a nonlinear stiffness constraint of a hydraulic cylinder. The method mainly comprises the following steps: establishing a vibrating model of the mill roll system under the nonlinear stiffness constraint of the hydraulic cylinder, and listing a dynamic equilibrium equation of the system according to a generalized dissipation Lagrange principle; introducing a controlled input quantity based on the dynamic equilibrium equation; simplifying the dynamic equilibrium equation with the controlled input quantity and constructing a Lyapunov function; giving a stability condition of the system through a Lyapunov theorem; properly adjusting the sizes of gains kd and kp, and controlling the mill roll system to reach a stable state; and comparing the stability of the uncontrolled system and the controlled system and correcting the model. The control method provided by the invention can effectively inhibit vibration of the mill roll system and improve the stability of the system, thereby providing a novel solution for controlling the stability of the mill roll system.

The invention discloses a sliding mode variable structure Buck circuit control method based on an extreme learning machine, and the method comprises the following steps: S10, carrying out the analysis of a Buck circuit topological structure, and building a system mathematical model through a state space averaging method; S20, defining a sliding mode surface of a controller, designing an extreme learning machine adaptive law, and designing the controller according to the system mathematical model in the S10; S30, verifying the existence of the sliding mode and the stability of the system by using the Lyapunov theorem according to the controller in the S20. Voltage and current signal changes of the circuit are monitored at the same time, and duty ratio signals output by a system are corrected in real time; the system can rapidly reach the sliding mode surface from any initial state, loads are switched when the circuit is in a steady state, the system can be stabilized to a steady-state output voltage value in a short time, the robustness of a controller is guaranteed, and system buffeting is weakened.

The invention discloses a current control method of a photovoltaic grid-connected inverter with the APF function. An inverse method is applied to a design of a current tracking control system; an instruction filter is introduced to deal with a problem of inverting input saturation; an instruction filter compensation signal is designed to reduce adverse effects caused by the instruction filter; and the stability and onvergence of the whole system are proved by the asymptotically stable Lyapunov theorem. Compared with the traditional APF, the control method enables the current tracking to be improved and the energy quality to be improved. Compared with the traditional PI algorithm, the method disclosed by the invention has the good dynamic performance and high robustness.

The invention provides an unmanned aerial vehicle anti-interference control method based on an internal model control principle. A physical system of an unmanned aerial vehicle is considered. The intelligent control method comprises the steps of establishing an unmanned aerial vehicle dynamics model with external disturbance, building an external disturbance system, designing an unmanned aerial vehicle distributed control algorithm with external disturbance based on theoretical knowledge such as graph theory and convex analysis, further designing a Lyapunov function. The convergence of the designed algorithm is proved through the Lyapunov theorem, it is guaranteed that the state variables of the unmanned aerial vehicle converge to the target, finally the effectiveness and feasibility of the method are verified again through a numerical simulation example, and dynamic tracking of the unmanned aerial vehicle and formation of the unmanned aerial vehicle can be well achieved under the disturbance condition. The control precision of the unmanned aerial vehicle system is improved, and the method has certain practical value in both civil and military aspects.

The invention discloses a sliding mode controller design method based on a multi-parameter self-adaptive neural network. The sliding mode controller design method comprises the steps: 1, establishing an n-degree-of-freedom rotary joint rigid mechanical arm dynamic model; 2, converting the model system in the step 1 into a second-order state equation based on a joint position, and designing a fast terminal sliding mode surface for the second-order state equation; 3, approaching unknown dynamic parameters of the system by using an RBF neural network; and 4, designing a self-adaptive nonsingular fast terminal sliding mode controller, and realizing model-free control of a mechanical arm based on the dynamic parameter approximation result in the step 3. The method is suitable for trajectory tracking control of the mechanical arm influenced by model uncertainty and external interference, the number of self-adaptive design parameters given in a control design program is reduced, and an unknown nonlinear function of robot dynamics is approximated on the basis of RBFNN; and in addition, the convergence speed and tracking precision of errors are improved, and global asymptotic stability based on the lyapunov theorem is achieved.

The invention provides an intermittent milling vibration subsection control method, which comprises the steps of analyzing the cut-in and cut-out process of an intermittent milling cutter, wherein thenon-cutting process is a free vibration state, and the cutting process is a forced vibration state, and carrying out time-lag dynamics modeling and subsection approximation on intermittent milling; designing a controller integrating time lag feedback and state feedback, and allowing an unstable phenomenon to occur in a forced vibration stage by taking the stability of the whole system as a target; and judging the stability based on the linear matrix inequality and the Lyapunov theorem, and determining controller parameters. The method provided by the invention has relatively small controllergain and relatively high stability discrimination precision.