381results about How to "Reduce conservatism" patented technology

The invention discloses a nonlinear self-adaption control method of near-space hypersonic vehicle (NHV), which belongs to a flight control method in the technical field of aerospace. The control method mainly comprises three control law parts: a nominal nonlinear generalized predictive control law (NGPC), a B-spline recursive functional linkage network (BRFLN) self-adaption control law, and a robust control law of gain self-adaption adjustment. The invention integrates the simplicity of the NGPC method and the effectiveness of dynamic uncertainty of the BRFLN learning, targets the immeasurable dynamic uncertainty and fast interference of an attitude system in the flight of the NHV, brings favorable learning effect, and realizes the nonlinear accurate control to the attitude angle.

The invention discloses an active fault tolerance control method of a four-rotor aircraft based on a sliding-mode observer. The active fault tolerance control method is provided by considering that a performer may have faults when the four-rotor aircraft is in a state delay condition and combining the sliding-mode observer with sliding-mode control. The sliding-mode observer is designed, linear transformation is carried out on the system, faults of the performer are reconstructed on the basis of the ideal of equivalent error injection, compensation control is added into sliding-mode control by utilizing the reconstructed estimation value of the performer faults, and a complete active fault tolerance controller is formed. According to the invention, the sliding-mode observer is designed, the faults are reconstructed and estimated, online adjustment of the controller gain is realized, the provided control law is optimal, the control precision and response speed of flight of the four-rotor aircraft are effectively improved, and a design basis of the fault tolerance controller is provided for the complex four-rotor aircraft with performer faults. The method can be applied to active fault tolerance control for the four-rotor aircraft with time variation and time lag.

The invention discloses an aircraft flutter prediction system and method which are used for solving the technical problem that an existing flutter prediction system is poor in prediction accuracy. According to the technical scheme, the system comprises an excitation signal generator, an excitation executing mechanism, a signal acquiring module and a data processing and flutter prediction module, wherein excitation signals generated by the excitation signal generator are input into a steering engine, the steering engine drives a control plane to deflect through a power booster according to a predetermined instruction so that gas power can be generated and excitation can be formed, and the control plane deflects at different speeds according to different input signals so that different external excitation forces can be generated and a test part can be fully excited. The signal acquiring module is used for acquiring acceleration responses and external excitation force response signals. According to each mach number, the data processing and flutter prediction module can predict a flutter critical point of the test mach number just through a subcritical speed testing point, prediction accuracy can also meet the requirement when the speed testing point is far away from the flutter critical point, and the prediction accuracy of the flutter prediction system is improved.

The invention provides an intelligent analysis system and method for magnetic flux leakage detection data in a pipeline. The process comprises the following steps: adopting time domain-based sparse sampling and KNN-softmax data complete set construction module, obtaining a complete magnetic flux leakage data set; a pipeline connection assembly discovery method based on combination of selective search and a convolutional neural network is adopted in the discovery module to obtain the accurate position of the weld joint; adopting an abnormal candidate region searching and identifying method based on a Lagrangian multiplication frame and multi-source magnetic flux leakage data fusion in the discovery model to find out defective magnetic flux leakage signals; Adopting a defect quantification method based on a random forest in a quantification module to obtain a defect size; a pipeline solution improved based on the ASME B31G standard is adopted in the solution module, and an evaluation result is output. An analysis method is provided from the overall perspective, and pretreatment, connection assembly detection and abnormity detection, defect size inversion and final maintenance decision are achieved.

The invention provides a modeling method for a production scheduling problem distribution set robust model, which belongs to the field of production scheduling and operations research. A distributed set robust optimization method based on an uncertain distribution function set is adopted to model the production scheduling problem, the model is composed of an objective function and constraint conditions, the objective of the model is to search for an optimal robust scheduling sequence, and thus, in a condition in which the total flow time of the sequence obeys the worst distribution in the processing time, the minimum condition risk value is realized. In the case of solution, the model is decomposed to an assignment subproblem and an integer two-order cone programming subproblem, and a minimum average processing time priority criterion and two Cauchy relaxation algorithms designed by the invention are adopted to optimize the model and obtain the optimal solution. The distribution set robust optimization method is applied to the production scheduling problem, the method is more applicable to the actual production condition compared with the existing robust modeling method, and in a condition of ensuring the system performance, a decision risk is reduced.

The invention relates to a method for controlling the structural modal vibration of a dual-frame magnetic levitation control moment gyroscope (CMG). On the basis of establishing a nominal model of an electromagnet rotor system, a sine-swept excitation mode is adopted to perform the identification of frequency domains on an electromagnet rotor and measure the disturbance of system parameters, the properties of structural vibration modality and the high-frequency unmodeled dynamics of an electromagnet rotor model; and a comprehensive robust control method of a structural singular value mu is utilized to select a weighting function and inhibit the structural modal vibration. The method belongs to the technical field of aerospace control, and can be used for inhibiting the structural modal vibration of the dual-frame magnetic levitation CMG.

The invention discloses a finite time robust fault diagnosis design method for a leader-follower multi-agent system. The method includes the steps: firstly, building a multi-agent system connection diagram with a leader and showing the multi-agent system connection diagram by a directed graph to obtain a Laplacian matrix L of a follower and an adjacent matrix G of the leader; building a state equation and an output equation of each node flight control system and augmenting a state vector and a fault vector into new vectors; constructing a distributed error equation and a global error equation based on the directed graph for each node according to the built directed graph, constructing a finite time fault diagnosis observer of a flight control system based on finite time robust control, and performing finite time fault diagnosis for faults of a multi-agent executor based on the directed graph. Faults of an optional node of the control system or simultaneously occurring faults of a plurality of nodes are effectively and accurately diagnosed and estimated on line in finite time.

The invention relates to a robust fuzzy predictive fault-tolerant control method for an interval time-varying-delaying system. The robust fuzzy predictive fault-tolerant control method includes the following steps that firstly, a T-S fuzzy model of a nonlinear system is constructed; secondly, the constructed T-S fuzzy model is converted into an expanded T-S fuzzy model; thirdly, according to the constructed expanded T-S fuzzy model, a fault-tolerant controller that satisfies a control law is designed; and fourthly, a gain of the fault-tolerant controller is solved in a form of linear matrix inequality and the robust fuzzy predictive fault-tolerant control law is calculated. According to the robust fuzzy predictive fault-tolerant control method for the interval time-varying-delaying system,the robust fuzzy predictive fault-tolerant control method with time-delay dependence is provided according to the fact that a type of the industrial process has the characteristics such as nonlinearity, uncertainty, unknown disturbance, interval time-varying-delaying and partial actuator failure, thus the industrial process operates more smoothly and efficiently, the performance of a system is improved, and the fault tolerance of the system is increased.

A system for controlling fuel injection parameters of a diesel engine is provided. The system includes an engine cylinder, a fuel injector, a glow plug, an ionization sensor and a controller. The fuel injector provides fuel to the engine cylinder and initiates the combustion process within the engine cylinder. The ionization sensor senses ionization during the combustion process and generates an ionization signal provided to the controller. Based on the ionization signal the controller is configured to control the fuel injection parameters, such as the number of injections, quantity and timing of each fuel injection events and the maximum rate of engine exhaust gas recirculation.

The invention discloses a fault-tolerant control method for a networked control system with time-varying delay. In view of conditions of parameter perturbation, time-varying delay, external disturbance and random failure happening to an actuator, a discrete time closed-loop nonlinear networked control system model is firstly built, a Lyapunov-Krasovskii function with the delay information is then built, a Lyapunov stability theory and a linear matrix inequality analysis method are used, sufficient condition for asymptotic stability of the nonlinear networked control system and existence of an H-infinity fault-tolerant controller are obtained, a Matlab LMI toolbox is used for solution, and a gain matrix for a non-fragile fault-tolerant controller is: K=K<->P; and conditions for optimizing the minimum disturbance rejection rate gamma is given, and the controller gain matrix K<*> optimized under the minimum disturbance rejection rate gammamin= square root of e is acquired. The condition of time-varying delay existing in the system is considered, the time-varying delay is analyzed and processed based on a free-weighting matrix method, and the conservation is reduced.

The invention relates to a distributed power generation system time lag output synergy control method based on event triggering; the method comprises the following steps: abstracting a distributed power generation system kinetic equation and building a mathematic model, and converting a distributed generating unit control problem into a multi-intelligent agent synergy control problem; building a combined state of a following intelligent agent according to a state quantity of each intelligent agent and a communication weight of the adjacent intelligent agent; using the combined states to designan event triggering mechanism, comparing and determining whether or not to update a control output signal of each following intelligent agent; considering influences on the synergy control by the signal transmission time lag, designing a controller form of each following intelligent agent, enabling each following intelligent agent and a leading intelligent agent to keep the constant states, reducing the computational complexity and traffic load, and finally realizing the distributed power generation system final stabilization. The method converts the distributed generating control problem into the multi-intelligent agent synergy control problem, thus accurately and fast controlling the output voltage and frequency.

The invention discloses a fault tolerant control method for a multi-agent system based on adaptive sliding mode control. The failure of the actuator in the second-order nonlinear multi-agent system isconsidered, combined with adaptive control and sliding mode control, a fault-tolerant control method is proposed. The consistency error variable is defined according to the relative state informationbetween the agents, and the sliding mode surface is designed based on the consistency error variable, and the sufficient conditions for the asymptotic stability are given. The method based on adaptive boundary estimation estimates the upper bound of the fault, which ultimately constitutes a complete sliding mode fault-tolerant controller. The method simplifies the complexity of the problem by designing a sliding surface based on the consistency error variable; combined with the advantages of adaptive control and sliding mode control, the designed fault-tolerant control law has good fault tolerance. The method is used for fault tolerant control of a multi-agent system with actuator partial failure.

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 provides a fault detection method of a nonlinear network control system based on an event triggering mechanism, and relates to the technical field of network system fault detection. Themethod comprises the following steps: firstly, establishing a T-S fuzzy model of the nonlinear network control system, setting an event triggering condition, establishing a fuzzy fault detection filter model, establishing a fault weighting system, and then establishing a fault detection system model; selecting an appropriate residual evaluation function and a detection threshold according to the fault detection system model, and detecting whether a fault of the nonlinear network control system occurs; and finally, further designing a parameter matrix and an event triggering matrix of a fault detection filter according to the stability of the fault detection system and sufficient conditions of existence of the fault detection filter. By adoption of the fault detection method of the nonlinear network control system based on the event triggering mechanism provided by the invention, the robustness to external disturbance and communication delay is greatly improved, and the limited networkresources and computing resources can be saved by the application of the event triggering mechanism.

The invention relates to a low rotating speed high precision control method of a control moment gyro gimbal servo system. The method solves the problems of friction interference and a disturbing moment caused by unbalanced rotor vibration of the control moment gyro gimbal servo system in a low speed operation process. The method comprises the steps of establishing a control moment gyro gimbal servo system kinetic model containing the friction interference and an unbalanced rotor vibration interference moment, performing control design on a frame servo system current loop via vector control andPI (proportional-integral) control methods, designing an interference observer to estimate equivalent interference formed by the friction interference and the disturbing moment caused by the unbalanced rotor vibration at a frame servo system speed loop, allowing the interference observer to offset an equivalent interference estimated value via a feedforward channel and designing a composite controller. The method has the advantages of high engineering practicability, high interference immunity and the like.

The invention relates to a predetermined time multi-agent system consistency tracking control method. The method comprises the following steps: designing a predetermined time distributed observer to estimate a tracking error within predetermined time; determining distributed observer parameters according to preset time; designing a non-singular terminal sliding mode consistency control protocol inpreset time, so that the follower multi-agent system can track the track of the leader agent system in the preset time; determining controller parameters which can ensure the continuity and the microcosmic property of the sliding mode surface and eliminate the control singularity; and deploying the proposed distributed observer and consistency control protocol on each follower agent to realize predetermined time consistency tracking. Compared with an existing fixed-time consistency scheme, the method has the advantages that the convergence time estimation with lower conservative property canbe obtained, and the conservative property of controller design can be reduced. Therefore, the method disclosed by the invention shows a wide application prospect in the application of a multi-agent system with higher requirements on control precision and convergence time.

The invention discloses a combined navigation method which is based on robust dissipative filtering, and relates to a combined navigation systematic method of strapdown inertia, satellite and astronomy. Firstly, the combined navigation method uses a strapdown inertia navigation system, a GPS receiver and an astronomical navigation system for forming a combined internal navigation system; secondly, according to the dissipative control idea of the modern control theory, the combined navigation method uses a linear matrix inequality (abbreviated as LMI) algorithm for designing a robust dissipative filter so as to implement the fusion of high-precision GPS position and the posture measurement information of speed and the astronomical navigation system; the combined navigation method completely exerts high reliability and usability of traditional navigation means, as well as high precision of satellite and astronomy navigation, and finally achieves the high-reliability and high-precision combined navigation that is based on multiple sensors.

The invention discloses a diagnostic design method based on limited-frequency-domain for gradual failure of a flight control system. The diagnostic design method comprises the following steps: firstly, acquiring a state equation and an output equation of the flight control system; secondly, constructing an error equation, an augmented error equation and a failure diagnosis observer gain matrix; finally, according to the acquired state equation and output equation of the flight control system, and the constructed error equation, augmented error equation and failure diagnosis observer gain matrix, obtaining a failure diagnosis observer of a discrete-time flight control system. The failure of the flight control system can be estimated through the failure diagnosis observer. On the basis of the characteristic that the frequency domain of the gradual failure is relatively low, and under the external high-frequency disturbance, the multi-constraint failure diagnosis observer based on limited frequency is designed in allusion to a flight control system model, thereby reducing conservatism of the conventional design method based on all-frequency-domain.

The invention relates to a nonlinear system fuzzy and repetitive output controller and a control method thereof. The nonlinear system fuzzy and repetitive output controller comprises an improved repetitive control module, a state feedback gain module and a fuzzy system module. The improved repetitive control module receives an output variable of a nonlinear system and carries out filtering and time delay processing, and sends an output variable thereof to the state feedback gain module; the state feedback gain module adjusts the output of the repetitive control module and carries out compensation thereon, and an output variable of the state feedback gain module is sent to the fuzzy system module; and the repetitive control module and the fuzzy system module are combined to form the fuzzy and repetitive output controller of the nonlinear system. The fuzzy model is applied to the problem of periodic tracking control of the nonlinear system for the first time, and T-S fuzzy control and repetitive control are combined to form a new high-performance control method; and for the design of a repetitive controller based on a fuzzy observer, with the problem of fuzzy premise variable non-measurableness in an actual system being taken into consideration, the design is more comprehensive.

The invention relates to an online identification method for the mass property of carrier rocket and the critical parameter of dynamics. The method is based on the six degrees of freedom aviation dynamics equation and the unknown parameter dynamic equation. Through constructing the augmented state equation to realize a simultaneous estimate for state and parameter, the parameter vector and state vector to be identified is thus obtained. The greatest advantage of the present method is to estimate unknown parameters according to the output. When the system is changed, the mass property and the estimation result of the critical parameter of the dynamics can be accurately obtained, and can establish key technical foundation for online optimization and adjustment of the control parameters of carrier rocket. Meanwhile, the identification method can realize the simultaneous estimation of state and parameters online. The method has significances for reducing the conservativeness of rocket system deviations and for increasing the adaptability to malfunctions by rocket, and provides beneficial references for future rocket design.

The invention provides a self-adaptive neural network automatic berthing control method for an underactuated ship. According to the method, an additional control method is adopted for solving the difficulty of design of an underactuated controller; uncertain ship model dynamic parameters and unknown disturbance vectors are reconstructed by utilizing a neutral network self-adaptive method of navigation dynamic depth information, the neutral network weight, approximate error and disturbance quantity are taken as complex uncertain parameters to be estimated on line, the problem that since disturbance and approximate error are separated to be processed, the unknown disturbance input cannot directly approach and the coupling property to the system is neglected is solved, the uncertain couplingproperty is considered, also the design conservatism is reduced, and also the system computation load is reduced; the input saturation of rudder and paddle executors are considered in the controller,and dynamic technology and minimum study parameter methods are introduced, so that the provided control method is more convenient, and the engineer is easy to realize.

The present invention discloses a non-fragile dissipative filtering method of a nonlinear networked control system. The method comprises the steps of firstly establishing a nonlinear networked filtering error system model on the conditions of considering the time delay and the packet loss of the nonlinear networked control system and the perturbation of the filter parameters, then constructing a Lyapunov function, and then utilizing a Lyapunov stability theory and a linear matrix inequality analysis method to obtain the sufficient conditions of the mean square exponential stability of a nonlinear networked filtering error system and the existence of a non-fragile dissipative filter, utilizing a Matlab LMI tool kit to solve, and definding a non-fragile dissipative filter parameter matrix. The method of the present invention considers the random time delay and the pocket loss situations between the sensors and the filters, is suitable for the general dissipative filtering including the H-infinite filtering, and enables the conservatism of the non-fragile dissipative filter design to be reduced. Moreover, a non-modeling state of the system is considered when a full-order filter is designed, thereby being able to reduce the calculation burdens and the design cost.

The invention relates to a no-gyro satellite gesture determination method based on tensor product multi-cell robust heavy hydrogen (H2) filtering, and belongs to the technical field of aircrafts. As for the nonlinear characteristics of satellite gesture dynamic equations and kinematical equations, the no-gyro satellite gesture determination method based on the tensor product multi-cell robust H2 filtering provides the multi-cell robust H2 filtering based on tensor product conversion to transform a nonlinear filtering problem into a linear filtering problem. The no-gyro satellite gesture determination method based on the tensor product multi-cell robust H2 filtering includes the steps of first establishing a state equation and a star sensor measurement equation of a gesture determination system and transforming a nonlinear system into a linear variable parameter error system by utilizing Jacobian linearization, then establishing linear parameter varying (LPV) system multi-cell model description according to tensor product model transformation and acquiring state estimation correction amount of the gesture determination system through combining with the robust H2 filtering, and last correcting gesture single-step pre-measurement acquired through a extended Kalman filter (EKF) method by utilizing the estimation correction amount to obtain a gesture estimation value. Accordingly, real-time updated filtering gain in the EKF method is avoid, and filtering calculated amount is reduced greatly.

The invention relates to a method for determining the anti-interference attitude in multi-source interference environment, and a test platform. The platform comprises a test master control module, an attitude control module, an actuating mechanism simulator, a real-time simulation target machine, a triaxial rate turntable, a sensor module, an attitude determination module and an interference injection module; the test plate is a generalized test platform, can complete injection of different types of interference noises through the interference injection module, and can select an attitude determination algorithm class in the attitude determination module to complete comparison analysis of the attitude determination algorithm filtering performances of different types of anti-interference attitudes; and the anti-interference attitude determination method can effectively solve the problem of attitude determination precision decrease caused by gyroscope first-order Markov noises, carrier vibration harmonic noises, Gaussian white noises and other multi-source noises of sensor modules; and the method and the test platform are suitable for ground simulation verification in the aviation and aerospace fields, and can be used in highly precise attitude and position measurement of a spacecraft attitude determination system.

The invention provides a bottled liquid impurity and liquid level detection method based on image processing. The bottled liquid impurity and liquid level detection method comprises following steps: a, images to be processes are collected and inputted by a camera; b, a memory space used for storing images obtained via each step of treatment is constructed; c, Gaussian filtering is adopted for image grayscale smoothing treatment; d, improved otsu auto-thresholding algorithm is adopted so as to obtain a threshold T1; e, the threshold T1 is subjected to amplification so as to obtain a new threshold T2; f, the threshold T2 is used for binary-morphology treatment of the images obtained via Gaussian filtering; g, detection on impurities and liquid level is carried out, and results are outputted; and h, the memory space is released. The bottled liquid impurity and liquid level detection method is capable of realizing self-adaptive adjustment of thresholds in a certain light range. It is shown by experiment results that the bottled liquid impurity and liquid level detection method is capable of identifying impurities with a diameter larger than 0.5mm, detecting liquid level accurately, giving an alarm on unqualified products, and rejecting unqualified products.