439 results about "Finite time" patented technology

A multimedia playing apparatus plays hypermedia titles each consisting of a plurality of monomedia objects including at least one finite time monomedia object such as a video object, which is formatted as a sequence of fixed-length playing sections such as video frames and functions as a base-axis object for providing a timing reference. The apparatus executes playing of a hypermedia title in accordance with processing time points specified as respective numbers of the playing sections, and stores and utilizes a plurality of sets of synchronization trigger data each of which designates that playing of a specific monomedia object other than the base-axis object is to be started, or is to be ended, at a specific processing time point, with the synchronization trigger data sets being successively accessed and used as the corresponding processing time points are respectively reached during playing of the hypermedia title.

The sensor fault detector is one in which each sensor signal is compared with a reference signal provided by e.g. a model of the system being monitored. Prior art sensor fault detectors subtract the output of the sensor and the corresponding reference signal from each other, and a fault is declared when the residual difference exceeds a prescribed threshold. However, modelling errors (such as scaling discrepancies), d.c bias and noise mean that faults are often wrongly declared, or alternatively that only large faults can be detected. These problems are overcome according to the invention by comparing the "shape" of the sensor signal with that of the corresponding reference signal (i.e. comparing the signal outlines) over a finite time window, using e.g. correlation techniques. A fault is declared when the shapes differ by a prescribed amount.

The construct described herein allows opposing tissues to form adhesions with either side of the construct, as part of the natural healing process. The construct however is multi-layered, wherein the space between the layers provides the protection from unwanted adhesions forming between and bonding separate tissues. In one embodiment, this space between layers of the construct may be developed spontaneously, that is the multiple layers are released by design after a finite time and the opposing tissues are free to move independent of each other, free of adhesions.

The invention discloses a three-dimensional multi-missile cooperative guidance method with finite time convergence. The method comprises the steps that for an unknown target, a multi-missile cooperative guidance model with attacking angle constraint in three-dimensional space is established; by adaptive control, integral sliding model control and a finite time consistency protocol, an acceleration guidance law in the sight direction is established to make all missiles hit the target at the same time; through the adaptive control and non-singular fast terminal sliding model control, and the acceleration guidance law in the sight direction is designed to make the finite time convergence of a sight angular velocity rate and a sight angle of each missile achieved. According to the three-dimensional multi-missile cooperative guidance method with the finite time convergence, all the missiles can hit the target at a desired angle at the same time on condition that no maneuvering information of the target is known, and at the same time the occurrence of buffeting is avoided.

The invention discloses a method for controlling a PMSM (permanent magnet synchronous motor) servo system based on friction and disturbance compensation. In the method, a feedforward compensation method based on a friction model is combined with an auto disturbance rejection technology and the feedforward compensation method is complementary with the auto disturbance rejection technology mutually. In the method, a Stribeck friction model is utilized to carry out modeling on system frictions, a GA (genetic algorithm) is adopted to carry out offline identification on parameters, and an estimated value generated by an identification model carries out feedforward compensation; a state observer in the auto disturbance rejection technology observes and compensates overcompensation or undercompensation of the frictions as well as nondeterminacy and external disturbance caused by modeling errors in the system; and finally a differential tracker and a nonlinear control law are used to arrange a transient process for fixed position signals, thus solving the conflict between rapidity and overstrike and ensuring stability of the system and finite time convergence. By using the combined control, the compensation capacity of the system for the frictional nonlinearity can be improved effectively, the low-speed performance of the system is improved, and the tracking accuracy and the anti-disturbance capacity of the system are enhanced.

An aerial vehicle finite-time adaptive attitude control method based on an improved power reaching law aims at a problem of aerial vehicle attitude stabilization with concentrated uncertainty. A sliding mode control method based on the improved power reaching law is utilized, and furthermore through adaptive controlling, the aerial vehicle finite-time adaptive attitude control method based on the improved power reaching law is designed. A terminal sliding mode surface is designed for ensuring definite-time convergence of a system. Furthermore through the improved power reaching law, a buffeting problem is reduced in an actual control system. Furthermore the adaptive controlling is used for a feedback control system which intelligently adjusts a self characteristic according to the environment change so that the system can operate in an optimal state according to some preset standards. The invention provides the control method which can reduce the buffeting problem of the sliding mode surface and a control torque and furthermore realizes uniform ultimate boundedness of finite time of the system on the condition that uncertainty and interference exist in the system.

The system and method of the present invention provides viewers access to a library of movies, or any other audio/video content available for viewing at anytime. Specifically, the method involves transmitting movies wirelessly to a set-top box in one's home and allowing movies to accumulate. A hard disk drive in the set-top box is used to store movies. In an exemplary embodiment, movies are wirelessly transmitted to the set-top box using a datacasting technology which allows data to be encoded onto standard television signals and transmitted using existing television transmitters and broadcast towers. Movies are transferred to the set-top box using a broadcast file transfer protocol and stored on the hard drive. Movies are “packetized” and these packets are continuously transmitted to the set-top box where they are incrementally reassembled. The user is not aware of what data is being sent to their set-top box. The movies are pushed down by the provider to reside passively in the box for a finite time period. Transmission of the data is controlled by the content or service provider. To ensure that movies are received in their entirety, the same movie may be broadcast to the set-top box several times. Any packets of data that were not received in the first attempt of transmission will be received with subsequent broadcasts. The set-top box is also connected to a phone line for billing purposes.

System and method for delivery of an electronic message from a sender unknown to a recipient when such message comprises a sender code verified by recipient's electronic message handler, thereby eliminating delivery of unsolicited bulk messages. Dispensing sender codes per recipient addresses thwarts senders of unsolicited bulk messages. Dispensing sender codes upon successful response to a human response question further thwarts bulk senders. Sender code calculation according to periodically changing factors limits sender code utility to finite time periods.

Signal “peak” and “valley” removal properties of mathematical morphology operators are exploited in a method and apparatus for detecting, removing, or improving fidelity of pacemaker signal components of the Electrocardiogram (ECG) at sampling rates well below the pacemaker signal Nyquist rate. The method works for the wide variability in pacemaker signal amplitude, width, firing frequency, and other characteristics encountered in practice, and it works for malfunctioning pacemakers that may fire at any point relative to the QRS complex of the ECG signal. Filtering operations require minimal digital storage and are computationally inexpensive (no multiplications), mainly involving “maximum” and “minimum” type signal detections over a finite time history of the input signal. This implies that the method can be inexpensively implemented on small instruments in either hardware or software. The method may also be used to estimate the height and polarity of the pacemaker voltage spike, even though the base sampling period may be longer than the width of the spike.

The invention relates to the technical field of satellite fault diagnosis and fault-tolerant control, and proposes a fault diagnosis method, which has very good robustness to external interference, isfree of influence of external interference in a fault diagnosis process, prevents generation of misinformation and missing report, and can effectively estimate fault severity. According to the satellite fault diagnosis and fault-tolerant control method based on a self-adaptive observer, first a satellite kinematics and dynamics model under an actuator fault and external interference influence isestablished to analyze influence of fault effective factors on a system; secondly, an observer is designed for a satellite fault system, a residual error evaluation function is established based on observer output and system actual output, an evaluation threshold value is obtained, and the purpose of fault detection is achieved; then, when occurrence of a fault is detected, a self-adaptive observer is designed to complete a fault diagnosis task; and finally, based on an estimated value of the fault, a finite time self-adaptive fault-tolerant controller is designed. The satellite fault diagnosis and fault-tolerant control method based on a self-adaptive observer is mainly applied to fault diagnosis and fault-tolerant control occasions.

The present invention provides an accurate track tracking control method based on a finite time expansion state observer. The method comprises the following steps of: establishing a mathematical modeland a kinematic equation representing current unmanned ship motion features, designing a combined nonsingular rapid terminal sliding-mode control law according to the unmanned surface ship motion tracking errors and a nonsingular rapid terminal sliding-mode surface, designing a finite time expansion state observer according to the unmanned ship motion features, and designing an accurate track tracking control law according to the combined nonsingular rapid terminal sliding-mode control law and the finite time expansion state observer. Through design of the finite time expansion state observer, the lump interference comprising external interference and a complex nonlinear term can be observed by the finite time to a small enough range to avoid the limitation of the approximation observation. Through the designed combined nonsingular rapid terminal sliding-mode control law and the nonsingular rapid terminal sliding-mode unmanned ship track tracking controller, the accurate track tracking control method achieves the accurate track tracking control performance in a complex external interference.

The invention provides a sight line based finite time convergence active defense guidance control method, relates to a guidance control method, in particular to an active defense guidance control method, and aims at solving the problem that a defensive missile is limited in overload capacity. The sight line based finite time convergence active defense guidance control method comprises the steps of firstly modeling relative motions of a target, the defensive missile and an intercept missile, adopting a sight line guidance mode to design a guidance rule for the defensive missile, then adopting a nonsingular terminal sliding mode to control the designed guidance rule, respectively defining sliding mode variables (shown in the description) of a longitudinal plane and a lateral plane, performing derivation on the sliding mode variables, substituting relative motion equations of the target, the defensive missile and the intercept missile into the variables and obtaining the guidance rule (shown in the description) of the longitudinal plane and the guidance rule (shown in the description) of the lateral plane through compilation, and controlling the missiles according to the guidance rules. By means of the sight line based finite time convergence active defense guidance control method, overload needed by the defensive missile can be effectively reduced. The sight line based finite time convergence active defense guidance control method is suitable for active defense guidance control.

A finite time robust cooperative tracking control method for a multi-robot system relates to a control method for a multi-robot system, and solves the problems that a conventional control method for a multi-robot control system is poor in robustness and the overall communication burden of the multi-robot system is too heavy. The method includes the steps: establishing a dynamics model, shown in the description, of each follower robot in the multi-robot system, wherein the dynamics model can be linearized as defined in the description; defining variables qri, zli and z2i; combining a virtual controller [alpha]1i to obtain a formula shown in the description; and designing a distributed control law shown in the description and a linear parameter self-adaptive law shown in the description. In this way, each follower robot can follow, within the finite time, a leader robot that has a dynamic time-varying track, tracking errors are bounded, and then finite time tracking control over the multi-robot system is completed. The method is suitable for the control field of a multi-robot system.

A rotary-table servo system neural network control method comprises (1) building a mechanical dynamic model of a permanent magnet synchronous motor rotary-table servo system, and initializing the system state, sampling time and relative control parameters; (2) according to the differential mean value theorem, enabling a non-linear input dead zone in the system to linearly approximate to a simple time-varying system, avoiding complex calculation of dead-zone inverse compensation, and finally inferring a rotary-table servo system model provided with an unknown dead zone; (3) at each sampling moment, calculating and controlling a system tracking error, a fast terminal sliding mode surface and a first-order derivative of the system; (4) based on the rotary-table servo system model provided with the unknown dead zone, selecting a neural network approaching unknown trend, designing an adaptive robust finite-time neural network controller according to the system tracking error, the fast terminal sliding mode surface and the first-order derivative of the system, and updating a neural network weight matrix; and (5) entering the next sampling moment, and repetitively executing the steps from (3) to (5).

The invention provides a finite-time full-order sliding mode control method of a quadrotor unmanned aircraft. For the quadrotor unmanned aircraft whose model parameters are coupled in a non-linear manner, a full-order sliding mode control method is utilized and a one-order filter is adopted to design the finite-time full-order sliding mode control method of the quadrotor unmanned aircraft. The design of full-order sliding mode surfaces ensures the rapid and stable convergence of the system. In a practical control system, two full-order sliding mode surfaces including the design position and attitude angle are degisned as inner and outer control rings to realize rapid tracking of the aircraft, and the filter is added to improve the buffeting problem. The invention provides the finite-time full-order sliding mode control method of the quadrotor unmanned aircraft, based on the condition that the system model parameters are coupled in a non-linear manner, rapid convergence to a balance point in finite time of the system is ensured, the response speed of the system is increased, the buffeting of sliding mode control input is improved, and the rapid and stable tracking performance of the system is effectively realized.

The present invention provides relating regular method of automatic finding judgment redundant alarm, which includes the following steps: (1) all history alarm is separated into some alarm subclass according to alarm class of all history alarm, each subclass correspond to a alarm class, then corresponding supporting degree and confidence degree of two alarm class is statistical according to random two alarm subclass, until all alarm class completes; (2) after completing all alarm statistical calculation between classes, listing relating alarm class in which supporting degree is bigger than prearranged threshold A and confidence degree is bigger than prearranged threshold B, adding to synthetic net management system, shielding or inhibition redundant alarm automatically. The present invention resolves calculate complexity degree problem of magnanimity history data, and can find relating rules of judging redundant alarm automatically in finite time, so compression rate of synthetic net management is improved greatly.

The invention provides an isolated island micro-grid layered distribution type control strategy based on a consistency theory. The isolated island micro-grid layered distribution type control strategycomprises the steps: firstly, a primary droop control strategy is proposed, a distribution type multi-loop controller based on droop control is designed and comprises an outer loop power controller and an inner loop voltage and current controller, distribution type power supply quick response is achieved, and the system voltage and frequency are stabilized; then based on a finite time consistencyalgorithm, a translational droop curve method and a voltage-reactive droop coefficient correcting method, distribution type secondary frequency control and secondary voltage-reactive control strategies are proposed, frequency and voltage deviations caused by primary droop control are corrected, and reactive power proportional distribution is achieved; and finally, an economic dispatching model isbuilt by considering the optimal total power generating cost of a micro-grid system as a target, solving is carried out by adopting a Lagrangian dual decomposition method, an isolated island micro-grid distribution type economic dispatching method is further proposed based on the finite time consistency algorithm, and thus the optimal output active power of all distribution type power supplies isindependently solved locally.

The invention discloses a finite time consistency-based distributed coordination control method for an island micro-grid. The control method comprises the steps as follows: (10) primary droop control is carried out, namely when the micro-grid is in power disturbance, droop control-based distributed power generation units and energy storage automatically control a frequency and a voltage of an output end, adjust power output and maintain the power balance of the micro-grid; and (20) secondary distributed control is carried out, namely under a distributed control framework, active power frequency control and reactive voltage control are simultaneously carried out to achieve that various distributed units undertake power shortage of the micro-grid and distributed recovery of the frequency and the voltage according to the adjustable capacity. The control method achieves distributed secondary recovery of the frequency and the voltage by a finite time consistency method, ensures that the droop control-based distributed power generation units and energy storage undertake power shortage according to the power capacity, maintains the frequency and voltage stability of the micro-grid and improves the reliability and the robustness of micro-grid control.

The invention discloses an adaptive control method of four-rotor aircraft finite time on the basis of a quick terminal slip form, and is suitable for a four-rotor aircraft system with inertial uncertainty and external disturbance. A linear slipping modal and a quick terminal sliding modal are comprehensively considered, a terminal attractor is introduced into the system sliding modal, so that a system state is converged in the finite time, the quickness of the linear slip form when an equilibrium state is approached is kept so as to quickly converge the system state to the equilibrium state inthe finite time. The invention applies the quick terminal slip form to put forward the adaptive control method of four-rotor aircraft finite time on the basis of the quick terminal slip form, a system singularity problem is avoided, buffeting is effectively inhibited, the method exhibits good robustness for the external disturbance and the uncertainty in a four-rotor aircraft system, and the system can quickly converge in the finite time.

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 discloses a finite time neural network optimization method for solving the inverse kinematics of a redundant manipulator. The finite time neural network optimization method comprises thefollowing steps that 1), an expected target track r*(t) and a joint angel theta*(0) expected to be returned of an end effector of the redundant manipulator are determined, and the end effector of the manipulator is deviated from the position of the expected track; 2), final state attraction optimization indexed are designed, a quadratic programming scheme based on the final state attraction is constructed, wherein an initial joint angle of the redundant manipulator during actual movement can be arbitrarily designated, the initial joint angle theta(0) of the redundant manipulator during actual movement is given, theta(0) is taken as a motion starting point, and the formed repeated motion programming scheme is described as the quadratic programming with the final state attractor optimization indexes; 3) a final state neural network model of a finite value activation function is constructed, and a finite value final state neural network is used for solving a time-varying matrix equation; and 4), the result which is obtained by solving the equation is used for controlling each joint motor to drive the manipulator to execute tasks. The finite time neural network optimization method has the advantages of being high in precision and capable of converging in finite time.