32 results about "Stability theory" patented technology

The invention relates to the technical field of underwater robot cooperative control, and provides an elastic consistency control method and system of a multi-underwater robot system. The elastic consistency control method for the multi-AUV system comprises the following steps: discretizing and linearizing the multi-AUV system, introducing a performance index to describe the influence of communication topology on the dynamic behavior of the system, and calculating the elastic consistency of the multi-AUV system on the basis of a centralized optimal control method of a local decoupling system and a robust stability theory. And designing an elastic consistency controller and obtaining controller gain by solving a local algebraic Riccati equation so as to realize consistency control of multiple AUV system states. According to a sparse mode matrix spectrum of a distributed controller, a system stability condition is given, and efficient cooperation and stable operation of a multi-AUV system in a complex underwater environment are ensured. According to the method, the calculation and communication complexity is remarkably reduced, the method is suitable for a multi-AUV cooperative working environment, and a new technical solution is provided for cooperative control of the underwater unmanned system.

The invention relates to the technical field of power electronics and direct current transmission, in particular to a two-level VSC-HVDC minimum direct current capacitance calculation method based on LMI. The method comprises the following steps: establishing a state equation comprising a main circuit and a controller dynamic model, converting a three-phase alternating current quantity into a direct current quantity under a synchronous rotating coordinate system by utilizing Park transformation, and deducing a system state equation in combination with a Kirchhoff's law; performing Taylor expansion and linearization on the nonlinear equation, and constructing a small signal model based on a Lyapunov stability theory; by separating a diagonal matrix and defining a stability criterion in an LMI form, minimum direct-current capacitance solving is converted into a convex optimization problem, a critical value is iteratively searched by adopting a dichotomy method to determine minimum capacitance, and meanwhile, a tolerance mechanism is introduced to improve the robustness of an algorithm. Through combination of mathematical modeling and an optimization algorithm, the calculation efficiency and accuracy are effectively balanced, and a theoretical basis is provided for reducing the cost and the size of the converter.

The invention provides a collaborative collision and obstacle avoidance strategy of an underactuated unmanned ship considering input and state quantification. The collaborative collision and obstacle avoidance strategy comprises the following steps: establishing a mathematical model of the underactuated unmanned ship; a distributed guidance rule is constructed in the USV kinematics subsystem by using an auxiliary variable method, and a repulsive force function of an improved artificial potential field method is introduced to reconstruct the guidance rule, so that collaborative collision avoidance and obstacle avoidance at the kinematics level and expected trajectory tracking of the underactuated USV are realized; designing an extended state observer to solve the influence of unknown items in the system and quantitative state variables in the communication process on the formation control system; a linear time-varying model is adopted to describe a quantizer, so that a bottom-layer quantization controller does not need to predict specific information of quantization parameters; and proving the stability of the constructed USV formation tracking control system according to an input-state stability theory. According to the invention, starting from two aspects of input quantization and state quantization, the problem of USV formation tracking control in the marine environment with limited communication bandwidth and complex quantization environment is solved.

A wind power generation system preset time maximum power point tracking control method comprises the following steps: firstly, establishing a wind power generation system dynamic model containing parameter uncertainty and external disturbance, and meanwhile, constructing a preset time convergence integral sliding mode surface; the method has the core advantages that the convergence time can be directly set by controller parameters and is irrelevant to the initial state of the system; secondly, designing a preset time self-adaptive controller based on the rotating speed tracking error and the sliding mode surface, and enabling the rotating speed tracking error to be quickly converged in preset time; the upper bound of lumped uncertainty of the system is estimated online through a self-adaptive mechanism, unknown dynamic and external disturbance are compensated in a unified mode, and dependence on an accurate model and disturbance prior knowledge is not needed; and finally, strictly proving the preset time stability of the closed-loop system through a Lyapunov stability theory. The method has good dynamic response performance and predictable convergence behaviors, and the robustness and the power generation efficiency of the system are improved.

The invention provides a multi-unmanned ship formation collision and obstacle avoidance control method with event triggering and signal quantification, which comprises the following steps: acquiring sea condition information of surrounding environment and other surrounding ships, and establishing a trajectory control mathematical model of an under-actuated unmanned ship formation; a uniform quantizer is adopted to quantize control input and state variables in the control system; estimating quantization state information of each USV and uncertain items existing in the model by using an ESO technology; a linear model is introduced to describe a quantization process, a hierarchical design method is adopted, a kinematics guidance law and a dynamics quantization tracking control law are designed, a controller does not need priori information of quantization parameters, and an event-triggered formation control strategy is designed; and the stability of the multi-unmanned ship formation collision and obstacle avoidance control system with event triggering and signal quantization is proved by using an input state stability theory. According to the invention, while an event triggering mechanism and signal quantization are considered, formation collision avoidance and obstacle avoidance of multiple USVs are considered.

The invention discloses a motor modeling and non-cascade servo control method and system based on T-S fuzzy. The method comprises the following steps: establishing a mathematical model on a two-phase synchronous rotation orthogonal coordinate system to obtain state space description; obtaining a T-S fuzzy model and a closed-loop system according to the state space description; and for the closed-loop system, determining the gain of the non-cascade servo controller based on the Lyapunov stability theory. According to the invention, the control performance and the anti-interference capability of the driving system are effectively improved, and parameter adjustment and physical realization are easy.

The invention discloses a multi-unmanned ship collision avoidance formation control method based on a BLF under generalized noise. The method comprises the following steps: S1, constructing a communication topological graph of an unmanned ship cluster based on a graph theory, constructing a Laplacian matrix, and defining a communication connection mode of the unmanned ship cluster; s2, establishing a linear dynamic model of the unmanned ship in combination with generalized noise definition, and defining a BLF according to the linear dynamic model; based on the local formation tracking error of the unmanned surface vehicle and in combination with the BLF, defining a collision-free formation tracking control protocol; and S3, an integral multiplicative obstacle Lyapunov function is combined with a stochastic differential equation stability theory to verify whether the collision-free formation tracking control protocol can enable the formation tracking error to be stable according to probability noise-state. According to the method, the collision avoidance algorithm is designed based on the BLF, the generalized noise is analyzed by using the stochastic differential equation, and the anti-interference capability of the multi-unmanned-ship formation is realized while the two core technologies guarantee that the multi-unmanned-ship safe formation is free of collision.

The application relates to a multi-agent cooperative control method and device for transmission data loss, and belongs to the technical field of multi-agent control. In the method, a directed network topology thought is introduced into information interaction of a multi-agent system, a Bernoulli distribution is introduced to express packet loss in a data transmission process between agents, a second-order dynamic system model of the agent is constructed to model the state, a following error equation of the multi-agent system is established, Liapunov stability theory and robust control theory are used to analyze the tracking error equation, a stability control condition is obtained, and thus a control gain coefficient capable of realizing consistent stability of the multi-agent system can be obtained by solving the stability control condition.

The application provides a hydraulic mechanical arm system fixed time compensation control method with input dead zone and unknown disturbance, and is aimed at a hydraulic mechanical arm system with input dead zone and unknown disturbance, and based on a backstepping design framework, a novel adaptive compensation controller with fixed time convergence is provided by using relevant mathematical lemmas and adaptive control technology. First, an observer is designed for parameter uncertainty and unknown disturbance of the system model by using the sliding mode control and fixed time theory, and the observer is compensated; second, a controller is designed based on the backstepping design framework; third, an input dead zone adaptive compensation mechanism is constructed based on Lyapunov stability theory. Simulation experiments show that the observer can well estimate and compensate the system output uncertainty caused by parameter uncertainty and unknown disturbance, and the system can maintain good tracking accuracy and realize rapid stability even if the system is affected by the input dead zone.

This invention discloses a fixed-time adaptive sliding mode control method and system for improving the disturbance rejection performance of downhole permanent magnet synchronous motors (PMSMs). The method includes: establishing a mathematical model of the PMSM considering parameter uncertainties and external load disturbances, defining parameter uncertainties and external load disturbances as lumped disturbances; constructing a fixed-time extended state observer to observe the lumped disturbances in real time based on fixed-time stability theory and obtain an estimate of the lumped disturbances; designing a fixed-time adaptive sliding mode control law based on the lumped disturbance estimate, generating a q-axis reference current, and realizing speed control of the PMSM; wherein, the adaptive sliding mode control law is derived by combining a non-singular fast terminal sliding surface, a fixed-time reaching law, an adaptive gain based on a variable gain rate smoothing factor, and the lumped disturbance estimate. This invention achieves fast and accurate convergence of disturbance errors within a fixed time.

The invention discloses a sliding mode control method based on a neural network adaptive observer, and belongs to the technical field of hydraulic position servo system control. The method comprises the following steps: establishing a nonlinear mathematical model of the hydraulic servo system; designing a state observer based on a radial basis function neural network, estimating each state in the system, and designing a system sliding mode control law by using observed parameters; designing a neural network adaptive law by using a Lyapunov stability theory; smoothing the output of the controller by using a filter; and proper controller hyper-parameters are selected, so that the system can realize an expected control effect and accurately track an expected signal. The control strategy designed by the invention can perform online estimation on nonlinearity which is difficult to model of the system, can accurately observe the state of the system, is good in steady-state performance, and is easy for engineering application.

The invention discloses a motor sliding mode control method and system based on an equivalent input disturbance observer. The method comprises the following steps: firstly, proposing a basic dynamic equation of the surface-mounted permanent magnet synchronous motor on a two-phase synchronous rotation orthogonal coordinate system, introducing a speed tracking error, and establishing a mathematical model of a singular perturbation system; then, an equivalent input disturbance observer is constructed and used for estimating lumped disturbance of the servo system in real time, and convergence conditions of the observer are given; and finally, obtaining the H-infinity performance of the closed-loop system based on the Lyapunov stability theory, and determining the gain matrix of the non-cascade sliding mode controller according to the corresponding linear matrix inequality. The method effectively improves the control performance and the anti-interference capability of the driving system, and is suitable for the design of a high-performance servo control system of the permanent magnet synchronous motor.

The application provides an event-driven multi-unmanned ship cooperative positioning and control method, and belongs to the field of unmanned surface vehicle control. The method solves the problem that the existing method is difficult to realize efficient and stable operation of the USV formation. The method comprises the following steps: establishing a ship body coordinate system, and constructing a USV dynamics and kinematics model; designing a follower formation controller, comprising: defining a desired distance and a desired azimuth angle, and deducing a formation error equation; combining Lyapunov stability theory to design a desired speed of the follower USV, and indirectly controlling the lateral speed by adjusting the yaw angular velocity; adopting an adaptive fuzzy logic system to approximate unknown nonlinear terms and unknown external disturbances of the follower ship, and introducing an auxiliary subsystem to process the amplitude and rate saturation of the actuator; designing a dynamic control law and an adaptive law; and proving the finite time stability of the closed-loop system based on Lyapunov stability theory. The method is used in the field of ocean control.

This invention belongs to the field of control engineering technology, specifically relating to a cement production control method based on equivalent input disturbance-linear matrix inequality (LMI). This method establishes a linear discrete time delay model predictive control system based on EID-LMI. In the establishment process, firstly, a control system structure consisting of the controlled object, an observer, and a low-pass filter is constructed using the disturbance compensation concept. Then, the EID estimate is obtained based on the equivalent input disturbance (EID) method, and a disturbance suppression law is designed. Next, using Lyapunov stability theory and combining performance indices, the index function is transformed into a minimized Lyapunov function. The design algorithm for the predictive controller is obtained through the LMI method. This invention has good anti-interference capability, high disturbance suppression performance, and the resulting control system is robust and stable.

The invention belongs to the technical field of random system control and sewage treatment, and discloses a T-S fuzzy Markov jump system control method based on an activated sludge system. According to the method, a nonlinear kinetic model is constructed from key state variables of the system, and the complex biological reaction and substance transfer process in sewage treatment is accurately described. By introducing the Markov jump theory, parameter random jump caused by inlet water quality sudden change and the like is effectively described, and the adaptability and accuracy of the model under the dynamic working condition are enhanced. For possible faults of an actuator (such as a dilution valve and an aerator), a fault model is established and a corresponding fault-tolerant control strategy is designed, so that the reliability and robustness of the system are improved. On the basis of the Lyapunov stability theory, a linear matrix inequality condition which enables the system to be randomly stable under the fault and disturbance and meets the H-infinity performance index is deduced, the effectiveness of the linear matrix inequality condition is verified through strict mathematical derivation, and a theoretical basis is provided for implementation of a controller and stable operation of the system.

The invention discloses a hydraulic arm position sliding mode control method based on an expansion state observer, which belongs to the technical field of electro-hydraulic position servo control, and comprises the following steps: step 1, establishing a state space model of a hydraulic mechanical arm joint position system; step 2, establishing a mathematical model of the extended state observer; 3, designing an improved sliding-mode active disturbance rejection controller based on an extended state observer, and replacing linear feedback with an improved sliding-mode control law while performing real-time observation and compensation on the comprehensive disturbance quantity of a joint position system of the hydraulic mechanical arm; and 4, carrying out stability proving on the improved sliding-mode active-disturbance-rejection controller by using a Lyapunov stability theory. According to the method, the disturbance quantity of the joint position system of the hydraulic mechanical arm is observed and compensated in real time, meanwhile, the improved sliding mode control law is adopted to replace linear feedback, the response lag phenomenon can be improved, and the control precision and robustness of the joint position system of the hydraulic mechanical arm are improved.

The invention provides a multi-USV trajectory tracking control method with ESO and signal quantization, and the method comprises the steps: obtaining the sea condition information of a surrounding environment and other surrounding ships, and building a trajectory control mathematical model of an under-actuated unmanned ship formation; a uniform quantizer is adopted to quantize control input and state variables in the control system; estimating the required quantization state information and uncertain items existing in the model by using the ESO technology; according to the idea of inner and outer rings, a kinematic guidance law and a dynamic quantitative tracking control law are designed, and a linear model is introduced to describe a quantitative process, so that a designed controller does not need to quantize prior information of parameters any more, and an event-triggered formation control strategy is provided to further reduce communication burden; based on the Lyapunov stability theory, the observation error of the extended state observer and the stability of the designed multi-USV formation trajectory tracking control system with signal quantization are proved.

The application relates to a multi-agent cooperative control method and device for transmission time lag, and belongs to the technical field of multi-agent control. In the method, a directed network topology thought is introduced into information interaction among agents in a multi-agent system, a second-order dynamic system model of the agent is constructed to model the internal state of the agent, a tracking error equation of the multi-agent system containing the transmission time lag is established, the tracking error equation is analyzed by using Lyapunov stability theory and finite time stability theory, and a stability control condition is obtained, so that a control gain coefficient capable of realizing consistency stability of the multi-agent system in a finite time can be obtained by solving the stability control condition.

The application discloses a preset index control method based on intelligent adaptive boundary adjustment, and the method is as follows: a preset performance boundary function basic form is designed, and a control equation under a constrained state is obtained according to a dynamic equation; a state variable capable of affecting control performance is selected, and a full feedback adaptive recurrent neural network model is combined to exert weight distribution on parameter values in the preset performance boundary function and subsequent control gain; an equivalent unconstrained conversion is performed on the constrained control model based on a barrier function, so that an unconstrained equivalent control model based on an auxiliary variable is obtained; a controller is designed by using a preset time stability theory and a backstepping method, so that a preset index controller design which can only adjust a control response speed by using one parameter and can constrain control performance is completed, and control gain can be set in advance according to a flight task and corresponding performance requirements. The method can fully exert the capability of the aircraft, and improve the control quality in any flight stage under a full flight profile.

The invention discloses an inverter grid-connected synchronous optimization control method based on a backstepping method, and belongs to the technical field of new energy grid-connected control, and the method comprises the steps: building a second-order nonlinear mathematical model of a phase-locked loop based on a grid-connected inverter phase-locked loop control structure, and deducing a state-space equation; decomposing the state space equation according to the state variable, and determining the virtual control quantity of each order of subsystem; defining an error variable by using the virtual control quantity, and recursively constructing a control law by using a backstepping method based on a Lyapunov asymptotic stability theory; and controlling the phase-locked loop by using the obtained control law to realize closed-loop control. According to the method, backstepping design is carried out on the phase-locked loop variable, on the premise that an original phase-locked loop structure is reserved, an additional control law is introduced, the robustness of the system under the condition that the power grid impedance is increased is remarkably improved due to the addition of the control law, the stability of voltage and current of a grid-connected point can be maintained, and the frequency hopping and instability risk can be effectively restrained.

The invention discloses a transient potential subsystem asymptotic stability discrimination method based on a combined system stability theory. The transient potential subsystem asymptotic stability discrimination method comprises the following steps: constructing a transient potential subsystem mathematical model of a power system containing a network-forming converter; calculating a first parameter meeting a first preset condition and a second parameter meeting a second preset condition according to a Jacobian matrix analytical expression in the mathematical model of the transient potential subsystem; constructing a matrix A containing excitation gain coefficients based on the first parameter and the second parameter; and judging whether the matrix A containing the excitation gain coefficient meets a preset criterion or not, and determining the asymptotic stability of the transient potential subsystem according to a judgment result.

The invention discloses an amphibious aircraft anti-storm fixed-point attitude stability control method, and belongs to the field of ship and rotor wing control. The method comprises the following steps: establishing a mathematical model comprising a rotor wing coupled amphibious aircraft water surface residence mode, wherein the mathematical model comprises an attitude kinematics equation and an attitude dynamics equation; defining a pointing stability control error form based on space vector projection; and designing a PD controller based on a Lyapunov stability theory, and outputting a control torque through the PD controller to realize three-axis attitude stability of the amphibious aircraft. Through a rotor wing auxiliary stabilization mechanism, rolling, pitching and yaw control requirements are unified, and the theoretical limitation of a traditional ship control model is fundamentally broken through.

This invention proposes a method and system for fixed-wing UAV habitat planning based on the attraction domain, belonging to the field of UAV control technology. The method includes step S1: acquiring the core state parameters and control parameters during the flight of the fixed-wing UAV; step S2: estimating the UAV's flight attraction domain based on the Lyapunov model, combined with the core state parameters and control parameters, to obtain an attraction domain set; and step S3: generating a reference flight trajectory based on the attraction domain set and landing target data. This invention also proposes a fixed-wing UAV habitat planning system based on the attraction domain. This invention ensures stable convergence throughout the entire UAV habitat landing process from the perspective of nonlinear system stability theory. Simultaneously, through lightweight modeling and simplified solution, it adapts to the onboard computing capabilities of small UAVs, effectively solving the core defects of existing technologies such as weak robustness, lack of stability guarantee, and complex calculations, enabling small fixed-wing UAVs to achieve precise habitat landing in small spaces without taxiing.

The invention relates to the technical field of electro-hydraulic position servo control systems of excavators, in particular to a trajectory tracking control method and device for a mechanical arm of an excavator, and the method comprises the following steps: S1, establishing a mathematical model of an electro-hydraulic position servo system of the mechanical arm; s2, identifying system parameters on line based on samples of a proportional pressure reducing valve and a multi-way valve of the excavator; s3, based on the mathematical model of the electro-hydraulic position servo system of the mechanical arm in the S1 and the identification parameters in the S2, a self-adaptive backstepping sliding mode controller based on a parameter layering strategy is designed, and tracking control is conducted on the track of the mechanical arm of the excavator through the self-adaptive backstepping sliding mode controller; and S4, a Lyapunov stability theory is used to carry out stability proving on the adaptive backstepping sliding mode controller in the S3, and an asymptotically stable system tracking error is obtained.

This invention discloses a sliding mode control method based on a neural network adaptive observer, belonging to the field of hydraulic position servo system control technology. The method involves: establishing a nonlinear mathematical model of the hydraulic servo system; designing a state observer based on a radial basis function neural network to estimate the states in the system, and designing the system's sliding mode control law using the observed parameters; designing a neural network adaptive law using Lyapunov stability theory; smoothing the controller output using a filter; and selecting appropriate controller hyperparameters to enable the system to achieve the desired control effect and accurately track the desired signal. The control strategy designed in this invention can estimate nonlinearities that are difficult to model online, accurately observe the system state, exhibit good steady-state performance, and is easy to apply in engineering.

The invention relates to the technical field of automation, in particular to a robot joint self-adaptive control method and system containing input saturation constraint. The method is based on a Newton-Euler method, nonlinear factors such as friction, gaps and time-varying stiffness and input saturation constraints are considered, and a two-mass kinetic equation of the micro driving system is established. And designing a disturbance observer based on a kinetic equation to estimate non-matching disturbance existing in the system, designing a state observer considering input saturation according to a state space equation and a disturbance estimation value, and observing all state variables of the system. And designing a neural network adaptive backstepping control algorithm considering input saturation according to the state observation value and the disturbance estimation value. Meanwhile, according to the Lyapunov stability theory, whether the system is consistent and stable in a semi-global mode or not is judged, and the control performance of the IT2-FCMAS-DSCABM control algorithm is verified by means of Matlab software.

The present invention relates to the field of power electronics and direct current transmission technology, specifically a method for calculating the minimum DC capacitance of a two-level VSC-HVDC based on LMI. The method comprises the following steps: establishing a state equation including a dynamic model of a main circuit and a controller, converting a three-phase AC quantity into a DC quantity in a synchronous rotating coordinate system using Park transformation, and deriving the system state equation in combination with Kirchhoff's law; performing Taylor expansion and linearization on the nonlinear equation, and constructing a small signal model based on Lyapunov stability theory; converting the minimum DC capacitance solution into a convex optimization problem by separating the diagonal matrix and defining a stability criterion in the form of LMI, and adopting a bisection method to iteratively search for a critical value to determine the minimum capacitance, while introducing a tolerance mechanism to improve the robustness of the algorithm. The present invention effectively balances computational efficiency and accuracy by combining mathematical modeling with an optimization algorithm, providing a theoretical basis for reducing the cost and volume of converters.

The invention discloses a multi-agent output feedback safety control method based on an average subsequence reduction algorithm, and belongs to the technical field of safety consistency control of a multi-agent system. The multi-agent control method solves the problem that an existing multi-agent control method is poor in safety and stability. According to the method, a strict feedback nonlinear multi-agent system mathematical model with unstructured uncertainty, time-varying disturbance, stateless measurement and Byzantine attack is established, the influence of Byzantine agents is eliminated by adopting a mean value subsequence reduction algorithm, and a fuzzy state observer which approaches an unknown nonlinear term and observes a state which cannot be measured is constructed. A virtual control law and an actual control law of a backstepping controller are designed based on a state estimation result of the fuzzy state observer and the apunov stability theory, and safe and stable consistency control of the multi-agent system under the Byzantine attack is achieved. The method can be applied to consistency control of multiple agents under the Byzantine attack.

The invention provides a water surface and underwater heterogeneous cooperative control method and system based on a predefined time terminal sliding mode. The method specifically comprises the following steps: establishing a water surface unmanned ship mathematical model and an underwater unmanned vehicle mathematical model; a vertical projection guidance method is adopted, so that the underwater unmanned vehicle obtains the actual navigation track of the water surface unmanned ship; constructing a nonlinear interference estimator according to the external environment disturbance, estimating the disturbance and compensating the controller; designing a control law based on a predefined time stability theory and a Lyapunov stability theory, and obtaining a predefined time terminal sliding mode controller to perform water surface and underwater heterogeneous cooperative control; and designing an underwater acoustic environment adaptive hierarchical compensation mechanism, and switching the unmanned surface ship tracking method according to the communication quality. Explicit time parameters are introduced, a user is allowed to directly set the upper limit of system convergence time, flexibility and low conservative property are both achieved, and theoretical guarantee is provided for quick response and safe operation.