30 results about "Lyapunov theorem" patented technology

The invention discloses a LMIs state feedback system control method based on an uncertain model. The LMIs state feedback system control method disclosed by the invention comprises the following steps of: establishing a controlled object model containing uncertain parameters at first, introducing a system state feedback controller, constructing a function of a closed-loop system, and designing a nonlinear system control law in the event of satisfying a Lyapunov theorem. The control method disclosed by the invention considers the control problems including influence caused by modelling error, model parameter variation, system noise and the like, of a system having uncertainty in a certain degree; the control method disclosed by the invention has good adaptive capacity to the uncertain factors of the system; in addition, compared with general conventional methods, the method disclosed by the invention is more rapid in response speed and higher in stability and robustness.

Based on neural network (Neural Network: Neural Network) technology and command filter inversion method, this application proposes a robust fault-tolerant control system design architecture based on command filter inversion. Firstly, the mathematical model of the NSV attitude control system is given, and on this basis, the uncertainty caused by modeling errors and external disturbances, and the state equation of the NSV attitude control system under control surface failures are considered. Its main design involves two units: one is the design of the auxiliary system, and the other is the design of the controller based on the auxiliary system. The auxiliary system introduces the neural network to ensure the robustness of the auxiliary system, and strictly proves the stability of the closed-loop system through the Lyapunov theorem. And the simulation is carried out on the attitude control system of the corresponding aircraft. The results show that the method proposed in this application can make the uncertain flight control system with external interference have ideal fault-tolerant tracking performance under the damage of the control surface.

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 relates to a formation flying spacecraft back-stepping sliding-mode control method, and belongs to the technical field of spacecraft posture adjustment. By the back-stepping sliding-modemethod, two distributed robust consistency tracking controllers are designed. The first robust controller can compensate known bounded external interface, is continuous and free from buffeting. In order to meet the use requirements of self-adaptive control, the second robust finite time controller does not need the upper bound of the known external interface. As the two controllers are designed based on a rotation matrix, attitude represented by the rotation matrix has global unique attribute, and the shortcoming of system unwinding can be overcome. By the aid of Lyapunov theorem, a whole closed-loop system is stable in finite time, simulation experiments prove that absolute attitude can be tracked, and formation member attitude consistency can be kept.

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 linear servo position tracking control based on linear matrix inequality and sliding mode control, the mechanical subsystem and the electrical subsystem are designed as a whole to control the design, and the complex problem that is difficult to solve is transformed into a relatively simple linear matrix inequality (LMI) problem, using The Lyapunov theorem proves the stability of the system, and then uses the MATLAB‑LMI toolbox to solve the result. Utilize the neural network thrust observer to conduct off-line learning of periodic nonlinear factors such as end effect and friction to ensure the real-time performance of the system, and then apply it to the system to observe the load disturbance, and finally achieve the purpose of the present invention, that is, to achieve a good robustness of the system Great track performance.

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 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 relates to an adaptive control method for target recycling of a space tethered robot after close-range capture. The adaptive control method comprises the steps of firstly deriving a compound body formed by the tethered robot and a captured target satellite, building a dynamic equation of the system in the recycling process, then designing the control force / moment in the recycling process according to a Lyapunov theorem, and designing a dynamic parameter identification law for the compound body, thereby achieving stable recycling of the compound body. According to the adaptive control method, the dynamic parameter identification law is put forwards for the first time, the whole recycling process can be enabled to be more accurate in calculation for control variables, and thus the recycling is more stable. The adaptive control method enables the compound body formed by the space tethered robot after capturing a non-cooperative target to be recycled stably and quickly through tether tension. The adaptive control method can overcome the natural instability in a problem of tether recycling on the basis of dynamic parameters of the compound body, and the compound body is recycled stably.

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.

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.