116 results about "Stability theory" patented technology

There is provided a method for detecting and locating leaks in a pipeline network in real-time. A flow model is provided that characterizes flow behavior for at least one of steady and unsteady states respectively corresponding to an absence and a presence of model leaks in the pipeline network, the flow model including a leaking factor kL. A deterministic model is provided to evaluate at least one of a leak status and a no leak status relating to the pipeline network using deterministic criteria. The deterministic criteria is based on a Liapunov Stability Theory. A deviation matrix is constructed based on the flow model and the deterministic model to generate eigenvalues. A leak alarm is generated when at least one of the eigenvalues is less than a predetermined value.

There is provided a method for detecting and locating leaks in a pipeline network in real-time. A flow model is provided that characterizes flow behavior for at least one of steady and unsteady states respectively corresponding to an absence and a presence of model leaks in the pipeline network, the flow model including a leaking factor kL. A deterministic model is provided to evaluate at least one of a leak status and a no leak status relating to the pipeline network using deterministic criteria. The deterministic criteria is based on a Liapunov Stability Theory. A deviation matrix is constructed based on the flow model and the deterministic model to generate eigenvalues. A leak alarm is generated when at least one of the eigenvalues is less than a predetermined value.

The invention discloses a motor position servo system control method taking an input time lag into consideration, and belongs to the field of electro-servo control. The method comprises the following steps: establishing a motor position servo system mathematic model taking the input time lag into consideration; designing an expansion state observer for observing a system state and interference in the mathematic model; designing a non-linear output feedback robustness controller for compensating the input time lag; and carrying out stability analysis on a motor position servo system taking the input time lag into consideration by use of a Liapunov stability theory, and proving that the system obtains half-global consistent and bounded stability. By use of an output feedback control method based on expansion state observer, non-linearity including external interference and the like is estimated through the expansion state observer and is compensated in controller design, such that the actual robustness of the motor position servo system for the external interference is improved, the influence exerted by speed measuring noise on system performance is overcome, and application in actual engineering is facilitated.

The invention provides a nonlinear coupling control method for a bridge crane based on generalized movement of a load by aiming at an under-actuated crane system. The nonlinear coupling control method has good trolley positioning and load hunting elimination performances. Compared with an existing crane control method, the method is applicable to not only stabilization control but also trajectory tracking control. The method includes: designing a signal similar to horizontal displacement of the load, and constructing a novel error signal on the basis, so that the coupling relation between a trolley and the load is enhanced. According to the novel nonlinear coupling control method, the crane system is converted into an interconnected system consisting of a load hunting sub-system and an error signal sub-system. The control performance of a closed-loop system is proved by means of inputting the state stability theory and the LaSalle's invariant principle. Experimental results show that good control effects can be obtained by the control method, and the method has good practical application values.

The invention discloses an on-line identification and control method for a parameter of an alternating current position servo system model. According to the invention, a model reference adaptive identification algorithm based on a Lyapunov stability theory is utilized; and on-line identification is carried out on a rotary inertia J and a viscous damping coefficient B of a controlled object of an alternating current servo system; after convergence is carried out on an identification parameter, an on-line design on a position controller is carried out according to J and B values and the design is automatically switched to position control. According to the invention, an efficiency on an alternating current servo system design can be substantially improved.

The invention aims at an intermittent process with uncertainty, and proposes a constrained 2D tracking control method for the uncertainty intermittent process. The constrained 2D tracking control method comprises the steps of: firstly, designing an iterative learning control law for a given system dynamic model; secondly, converting the original system dynamic model into a 2D-FM closed-loop systemmodel expressed in the form of a predictive value according to a 2D system theory and the designed iterative learning control law through introducing state errors and output errors; and finally, giving a sufficient condition expressed in the form of a linear matrix inequality (LMI) for ensuring robust asymptotic stability of a closed-loop system and an expression form of the optimal control law according to a designed infinite time domain performance index and a Lyapunov stability theory. According to the constrained 2D tracking control method, numerical values of tracking errors under the control of the constrained 2D tracking control method are smaller, and the convergence is faster; more importantly, the control input does not drastically fluctuate and only require slight adjustment, thereby being conducive to resource conservation and reducing troubles caused by frequent operations.

The invention relates to a power-reaching-law-based sliding-mode controlled magnetic suspension train system control method. Based on a single magnet structure magnetic suspension system model, and onthe basis of performing linearization on the input and output relation, the power-reaching-law-based sliding-mode controlled magnetic suspension train system control method analyzes the control relation of the application of sliding-mode control of the power reaching law in the single magnet structure magnetic suspension system, and utilizes a Lyapunov stability theory to analyze the stability ofthe method. The Matlab simulation result shows that compared with traditional sliding-mode control, the sliding-mode control of the power reaching law has better control performance, and has the advantages of significantly weakening buffeting, being smaller in the positional signal error, being better in dynamic characteristic, and being higher in robustness.

The invention discloses a four-rotor UAV flight control method based on a fractional order power switching law. A whole controller is of a backstepping control structure, a second-order nonlinear system of a quadrotor UAV is split into two subsystems, control laws that satisfy Lyapunov's stability theory are constructed, and the two subsystems are in series connection through a virtual intermediate control variable to form the complete controller, so that the controller can well adapt to the nonlinearity of the system and have good integrity. At the same time, in order to enhance the anti-disturbance capability and robustness of the controller, in the second backstepping design, the controlled variable is subjected to the sliding mode control design, which introduces the high disturbance resistance and high robustness of the sliding mode control. .

The invention, which belongs to the advanced control field of the industrial process, relates to a time-varying-delay-and-interference-based hybrid 2D tracking control method of an injection molding process. An injection molding process is represented by a typical multi-stage batch process; an error is introduced and an injection molding process two-dimensional augmentation model is built to obtain a two-dimensional state space time-delay system model; a state space model of an equivalent 2D switching time-delay discrete system is established; according to different stages, a segmented Lyapunov function with time-delay information is selected; on the basis of a 2D stability theory, an anti-jamming 2D controller that has extension information and depends on the upper limit and lower limit of the time delay as well as switching time is calculated. According to the invention, a control method enabling the process to be operated stably and the control precision to be improved obviously isdeveloped, so that objectives of reducing the cost investment and improving the production efficiency are achieved; and a problem that the system performance is reduced and even is not stable becauseof the delay phenomenon is solved.

The invention discloses a self-regulating error symbol integration robust control method for a direct-drive motor system. The method comprises the steps of establishing a mathematical model of the direct-drive motor system; designing a self-regulating error symbol integration robust controller; carrying out stability certification on the direct-drive motor system by using the Lyapunov stability theory, and acquiring a result of the global asymptotic stability of the system by using the Barbalat lemma. The self-regulating error symbol integration robust control method integrates the idea of self-adaptive control based on a traditional error symbol integration robust control method, and designs a controller gain self-regulating law so as to carry out on-line regulation on an integration robust gain value of the RISE controller. The self-regulating error symbol integration robust control method effectively solves problems of randomness, conservation, limitation and potential high-gain feedback in symbolic function gain regulation of a traditional RISE control method, and acquires better tracking performance.

The invention discloses a self-adaption fuzzy neural compensating nonsingular terminal sliding mode control method of a micro gyroscope. The method mainly involves a nonsingular terminal sliding mode controller and a fuzzy neural network compensating controller; the designed nonsingular terminal sliding mode enables that a system can reach a sliding mode surface and a balance point within a limited time from any initial state, and therefore, the convergence rate and steady stacking precision of the system are improved; meanwhile, the fuzzy neural network compensates the parametric modeling error of the micro gyroscope and outside disturbance effect on line, in order to improve the tracking performance; the fuzzy neural network is practiced on line, the self-adaption learning algorithm of weight of the fuzzy neural is on the basis of the lyapunov stability theorem, which ensures the tracking performance and the stability of the whole control system. The simulation result shows that the method is able to improve the problem of trace tracking of the micro gyroscope and can also effectively inhibit the parameter uncertainty and the influence from the outside disturbance, and as a result, the robust tracking can be realized.

The invention discloses a near-space aircraft control system, which belongs to the technical field of aviation aerospace propulsion control. The near-space aircraft control system aims at the attitudestable tracking control problem of a near-space aircraft, and considers the problems of unknown interference and parameter uncertainty. According to the near-space aircraft control system, firstly, an estimated value of an interference observer for interfering the outside world, then the parameter uncertainty of the aircraft is analyzed, and a self-adaptive estimated value of the aircraft parameters is obtained; secondly, an integral sliding mode surface is selected thus a self-adaptive integral sliding mode controller is designed for tracking control of an inner ring attitude angle of the near-space aircraft; and finally, the stability of the controller is proofed by utilizing a Lyapunov stability theory. The near-space aircraft control system can ensure the global stability of a closed-loop system, and enable the system to have good tracking performance and robust performance.

The invention discloses an inversion adaptive fuzzy sliding mode control method for a micro gyroscope. On the basis of advantages of inversion design and Lyapunov stability theory proof, the control law of the system is obtained step by step through a regression method, the fuzzy control does not need to rely on a mathematical model of a controlled object, the adaptive algorithm and the fuzzy control algorithm are combined, the defect that the fuzzy control cannot conduct parameter adjustment in time is overcome, a controller has the learning capacity, and in the control process, parameters have the self-learning and adjustment capacity. According to the method, the tracking performance of the micro gyroscope system can be effectively improved, the overall stability of the system is ensured, the robustness and the reliability of the system are improved, and the dependency on a controlled system model is avoided.

The invention discloses a control method for mixed trigger consistency of uncertain multi-agent systems with time delays and switching topologies, aims at the mixed trigger consistency problems of theuncertain multi-agent systems with time delays and switching topologies, and belongs to the technical field of multi-agent consistency control. Control problems for the mixed trigger consistency of the uncertain multi-agent systems with time delay and switching topologies are researched. A mixed trigger mechanism is described by adoption of a Bernoulli variable, so that the burden of the networktransmission is lightened. A mathematic model for closed-loop uncertain multi-agent systems is established. A sufficient condition for making the control systems consistent is given on the basis of aLyapunov stability theory and a linear matrix inequality theory. The switching of topologies in the systems is described by utilizing a Markov hop with an uncertain transfer rate. According to the control method, the consistency of the uncertain multi-agent systems can be realized through analyzing the influences, on the systems, of time-varying time delays and uncertain switching topologies, andthe calculation is simple and effective.

The invention discloses an improved function projection method of a complicated dynamic network. establishing a four-dimensional segmented Lorenz-Stenflo chaotic system model with an known parameter, and analyzing characteristic of Liapunov exponent; constructing a response system through utilizing the Lorenz-Stenflo chaotic system as a driving system; designing a projection synchronization controller, and automatically adjusting a feedback coefficient according to error magnitude and state change; and designing an adaptive identification estimator and a parameter updating rule. The improved function projection method is based on fractional order system stability theory combined adaptive control; and a lag improvement projection synchronization method is generated so that the method can realize synchronization between the state of a response node and the state of the driving system at a previous certain time according to a preset desired-dimension function matrix.

The invention provides a chaotic trajectory tracking method with pole assignment improved,and belongs to the technical field of automatic control. The chaotic trajectory tracking method specifically comprises the steps that a trajectory tracking error system is set up according to a state equation and expected trajectory of a chaotic system; a pole assignment method and a self-adaptation sliding mode controller are combined to design a controller,a self-adaption rate is designed for estimating modeling uncertainty and the upper bound of external interference signals,and the controller controlsthe trajectory tracking error system. The modeling uncertainty and the upper bound of the external interference signals are estimated through the self-adaptation rate,the controller is designed to carry out trajectory tracking control over different initial state chaos,the advantages of the pole assignment method are brought into play,the influence of the modeling uncertainty and the external interference signals is overcome,and very good robustness and very high reliability are achieved. The Lyapunov stability theory proves that the trajectory tracking error is asymptotically converged to zero,and chaotic system trajectory tracking can be achieved. The method is suitable for all chaotic systems,and the trajectory tracking speed is very high.

The invention discloses a method for controlling an active power filter based on model reference self-adaptive fuzzy control. The method comprises the steps that (1) a dynamic model of the active power filter is established; (2) a reference model is selected and a state space model of the reference model is shown as the formula (14); (3) a generalized state tracking error of the active power filter is defined as that e=xm-x (15); (4) T-S fuzzy approaching output of a non-linear portion of the active power filter is designed; (5) a current self-adaptive controller, composed of a T-S fuzzy control item and a sliding mode control item, of the active power filter is designed; (6) a system is proved to be stable through the stability theory and it is guaranteed that the tracking error e converges at zone; (7) a PI controller is used for controlling voltage across the direct current side of the active power filter. According to the method, the compensation performance and the robustness of the active power filter can be greatly improved, the power quality is effectively improved, and the method is beneficial to rapid popularization of the active power filter.

The invention relates to the field of micro gas bearing testing technology, and discloses a static and dynamic characteristics and stability test method for a micro gas bearing. The method includes the following steps of 1) before test, calibrating an initial position of a test bearing rotor; 2) continuously acquiring test data of the test bearing rotor; and 3) conducting calculation to obtain static and dynamic characteristic parameters and graphs of the test bearing rotor, and judging the stability of the test bearing rotor; and conducting calculation and solution by substituting the test data into a model equation of MATLAB to obtain the stiffness and damping of the test bearing rotor in different working conditions, constructing a stability characteristic equation according to the stiffness and damping, and judging the stability of the test bearing rotor according to the stability characteristic equation and the bearing stability theory. The stability test and control method for the micro gas bearing is easy to operate and small in calculation amount, and can be used for continuously measuring and calculating the static and dynamic characteristic parameters of the test bearing rotor in different working conditions and judging the stability of the test bearing rotor.

The invention relates to a transition Reynolds number acquisition method under the condition of flight. Firstly, shrinkage model test meeting the test similarity criterion is carried out in a ground wind tunnel to obtain a transition Reynolds number under the ground simulation condition; secondly, air-ground difference analysis is conducted, and the change data of the transition Reynolds number with an amplification factor N at different wall temperatures is given based on the flow stability theory; thirdly, the change law of the reference value of the transition Reynolds number with the walltemperature is obtained, and a wall temperature correction formula is obtained through curve fitting; fourthly, the change data of the transition Reynolds number with the amplification factor N afternormalization is obtained, and a noise correction formula is obtained; and finally, a unified extrapolation formula is formed, and a transition Reynolds number under the condition of flight is obtained through extrapolation based on a ground transition Reynolds number. The method has the advantage as follows: the transition test data is highly reliable and accurate, the cost of the method is muchlower than that of a method in which an association formula is obtained through test data fitting; and the data obtained by the stability theory is more regular, and the function relation is more accurate.

A milling flutter online optimizing method includes the following steps that S10, a milling regeneration flutter kinetic model is established; S20, a system starts to work, online monitoring based on the stability prediction technology is conducted according to the kinetic model, whether the system predicts an unstable machining phenomenon is judged, and the S30 step is executed if the system predicts the unstable machining phenomenon; S30, a control system automatically conducts stable zone optimizing according to the rotating speed of a spindle; S40, after the control system finishes stable zone optimizing, the step S20 is executed again to judge the optimizing control effect until machining is finished. According to the method, by establishing the milling kinetic model, stability prediction machining parameter automatic search control is achieved, milling parameters do not need to be repeatedly adjusted, the probability that stability theoretical analysis does not conform to an actual work state is avoided, and the defects of theoretical research are overcome.

The invention belongs to the field of wind-driven generator control technology and relates to a double-fed wind power generation system side converter back-stepping variable structure control system. The invention discloses a double-fed wind power generation system side converter back-stepping variable structure control system and method and a double-fed wind power generation system based on the system, and the system comprises a mathematical model establishment unit (11), a current instruction value calculation unit (12), a back-stepping variable structure control unit (13) and a space vector pulse width modulation unit (14); the method is based on Liapunov stability theory, back-stepping variable structure control algorithm design is performed under a two-phase synchronous rotating reference frame wind-driven generator mathematical model, and active and reactive power decoupling control of the system is realized; in order to eliminate disturbance influence in system actual operation, a variable structure control step containing an uncertain degree PI prediction scheme is added, so that sub-systems can satisfy Lyapunov asymptotic stability conditions when suffering from the disturbance. The dynamic property of the double-fed wind power generation system is further improved, and the parameter robustness of the system is enhanced.

The invention discloses a networked multi-sensor fusion fault detection method, and belongs to the field of networked systems. The method comprises the steps of firstly establishing a double-time-scale system model with parameter perturbation and faults, solving the data communication problem of a shared network through a weighted Try-Once-Discard protocol, designing a local fault detection filterand a global fusion fault detection filter, and introducing a residual evaluation mechanism to judge whether the system has faults or not; applying a Lyapunov stability theory and an LMI technology to obtain the sufficient conditions of the local fault detection filter and the global fusion fault detection filter; and using an LMI toolbox to solve the optimization problem, and obtaining a local optimal fault detection filter parameter and a global optimal fusion weight parameter. According to the method, the parameter perturbation, network bandwidth limitation and faults of the system under the actual condition are considered, and the method is suitable for the fault detection of a general networked system and has better universality.

The invention discloses a four-rotor unmanned aerial vehicle flight control method based on a fractional-order control algorithm. According to the method, a controller is of a back-stepping control structure on the whole, a second-order nonlinear system of a four-rotor unmanned aerial vehicle is divided into two subsystems, control laws meeting Lyapunov stability theories are built, and the two subsystems are serially connected into a complete controller through virtual intermediate control variables, so that the controller can effectively adapt to nonlinearity of a system and has good integrity. Besides, in order to enhance the anti-disturbance capability and robustness of the controller, sliding mode control design of controlled variables is performed in second back-stepping design, andhigh anti-interference capability and high robustness of sliding mode control are introduced.

The invention discloses a design method of a control system of a flying robot carrying a redundancy mechanical arm. The design method is used for achieving the design of a six-rotor aircraft self-adaptive stabilized flight controller and a redundancy mechanical arm controller, and mainly comprises the following steps that dynamics modeling is conducted on the flying robot carrying the redundancy mechanical arm according to the flight real-time operation data; then a position controller, a height controller and a posture controller are designed according to a modeling equation, and trajectory tracking treatment is conducted by use of a pushback method based on the liapunov stability theory; self-adaptive treatment is conducted, and therefore the design of the aircraft self-adaptive stabilized flight controller can be accomplished; and the mechanical arm motion planning scheme design and the quadratic programming design are adopted by the redundancy mechanical arm motion planning controller. The self-adaptive pushback design method can rapidly and accurately track the target trajectory of an aircraft in real time, and improves the robustness and the stability of the system.

Automated parameter tuning techniques for cross-directional model predictive control for paper-making under user-specified parametric uncertainties are developed. The CD-MPC design explicitly accounts for parametric model uncertainty while finding a value for the CD profile trajectory generation that minimizes the CD settling time of the measurement 2 sigma spread and does not exceed an overshoot limit for actuator 2 sigma spread. The inventive technique includes: (i) providing uncertainty specifications for the temporal parameters of the process model, (ii) specifying 2 sigma overshoot limits for the CD actuator profile, (iii) using robust stability theory to find a minimum bound for the profile trajectory tuning parameter, (iv) using a frequency domain technique to reduce the search range for the profile trajectory tuning parameter, and (v) performing an intelligent search for the tuning parameter that minimizes measurement 2 sigma settling time without exceeding the actuator 2 sigma overshoot limit.

The invention relates to an estimation method for false data attack of a load frequency control system. The method comprises the following steps: firstly, establishing a mathematical model of the load frequency control system according to a dynamic model of a power system; then, aiming at the situation that a power grid frequency measurement value and a tie line power measurement value are attacked by false data injection, analyzing the influence of an attack signal on a system state equation, and establishing a load frequency control system mathematical model containing a false data injection attack signal; then, designing a self-adaptive observer, and estimating a system state and an attack signal; and finally, solving the observer gain based on a linear matrix inequality method by using a Lyapunov stability theory and a robust H-infinity optimization index, and ensuring the convergence and the bounded property of an attack signal estimation error of the load frequency control system. According to the method provided by the invention, the false data injection attack signal of the load frequency system can be accurately estimated, the external interference can be suppressed, and the method has the advantages of simple design and easy engineering implementation, and has very high practical value.

The invention discloses an adaptive control method for a fractional order system influenced by saturated nonlinear input, and the method specifically comprises the following steps: building a fractional order system mathematic model for describing a class of physical objects or processes, and carrying out the designing of a fractional order sliding mode surface according to a fractional order calculus theory; determining an adaptive updating law of unknown parameters in the fractional order mathematical model; designing a self-adaptive controller of the controlled system according to a fractional order stability theory and a saturated nonlinear input characteristic; and searching an appropriate Lyapunov function to verify the finite time accessibility of a sliding mode approaching stage. According to the invention, the adaptive control of the fractional order system under the influence of input nonlinearity can be realized; when unmodeled dynamics with unknown upper bound and external interference occur in the system, it can be guaranteed that a state trajectory reaches a sliding mode surface within limited time under the action of a designed controller; through the sliding mode action, the purpose that the state trajectory of the controlled system converges to zero is achieved, the self-adaptive identification of unknown parameters is achieved, and the control purpose is achieved.

The invention relates to a saturated switching control method for a three-phase parallel active power filter. The method comprises the following steps of: 1) establishing a switching system model according to each operation mode of the three-phase parallel active power filter; 2) constructing a common Lyapunov function to obtain state-feedback-based switching rules, wherein arg represents a subscript meeting an expression; 3) introducing an additional matrix G in case of saturated nonlinear constraints of the three-phase parallel active power filter, linearizing the saturated nonlinear constraints by using a convex domain method, and designing saturated switching rules capable of progressively stabilizing a saturated system by utilizing a Lyapunov function stability theory; and 4) compensating the harmonic current of a power grid by using the three-phase parallel active power filter under the action of the saturated switching rules.

The invention discloses a permanent magnet rotating speed difference clutch and a self-adaption nonsingular terminal slip form rotating speed control method thereof. The method is characterized in that (1) an outer rotor of a permanent magnet rotating speed difference clutch is connected with an engine, and an inner rotor is connected with a steering pump, and then a permanent magnet rotating speed difference clutch type electronically controlled hydraulic power steering system can be formed; (2) a permanent magnet rotating speed difference clutch mathematic model can be established, and comprises a voltage equation, an electromagnetic torque equation, and a motion equation; (3)according to the mathematic mode, the self-adaption nonsingular terminal slip form surface can be designed by adopting the self-adaption nonsingular terminal slip form control method, and the control law can be deduced, and the self-adaption law of the parameter uncertain factors can be designed by adopting the Lyapunov stability theory, and the stability of the control system can be guaranteed. By adopting the self-adaption nonsingular terminal slip form control method, the problems of the system parameter perturbation and the external interference uncertainty can be overcome, the jitter can be reduced, the strong robustness can be provided, the accurate control over the permanent magnet rotating speed difference clutch output rotating speed can be realized, and the tracking error can be reduced to zero quickly.

The invention discloses a method for designing a controller of a non-minimum-phase constant-temperature continuous stirred tank reactor. According to the method for designing the controller, the stability of the zero dynamic inside a system can be guaranteed while it is guaranteed that the external dynamic of the system meets the performance requirement. The method for designing the controller of the non-minimum-phase constant-temperature continuous stirred tank reactor comprises the steps that firstly, system modeling is conducted on the continuous stirred tank reactor (CSTR) according to the actual production process, so that a nonlinear mathematical model of a control system is obtained; secondly, accurate feedback linearization is conducted on an obtained nonlinear system according to the state feedback linearization theory, so that a linear standard form of the nonlinear system is obtained; finally, the nonlinear controller of the constant-temperature CSTR having the non-minimum-phase characteristic is obtained based on the linear standard form according to the quadric form optimal control theory and the Lyapunov stability theory. The controller can be finally obtained through a digital signal processor, namely a DSP controller, by means of software programming.