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1021 results about "Tracking error" patented technology

In finance, tracking error or active risk is a measure of the risk in an investment portfolio that is due to active management decisions made by the portfolio manager; it indicates how closely a portfolio follows the index to which it is benchmarked. The best measure is the standard deviation of the difference between the portfolio and index returns.

Vehicle multi-objective coordinated self-adapting cruise control method

InactiveCN101417655ALoop controlDriver/operator
The invention relates to a multi-objective coordination-typed self-adaptive cruise control method for a vehicle, comprising the following steps: 1) according to the detail requirements of the multi-objective coordination-typed self-adaptive cruise control for a vehicle, the performance indicators and I/O restriction of MTC ACC are designed, and multi-objective optimization control problem is established; and 2) MTC ACC control law rolling time domain is used for solving the objective optimal control problem, and the optimal open-loop control quantity is used for carrying out feedback and achieving closed-loop control. Based on the steps, the control method comprises the following four parts of contents: 1. the modeling for the longitudinal dynamics of a traction system; 2. the performance indicators of MTC ACC; 3. the I/O restriction design of MTC ACC; and 4. solution by the MTC ACC control law rolling time domain. By constructing multi-objective optimization problem, the control method not only solves the contradiction among the fuel economy, the track performance and the feeling of the driver, moreover, on the same simulation conditions, compared with the LQ ACC control, the control method simultaneously reduces the fuel consumption and vehicle tracking error of the vehicle, and achieves the multi-objective coordinating control function.
Owner:TSINGHUA UNIV

Quadrotor unmanned plane control method based on fuzzy expansion state observer and adaptive sliding formwork

The invention relates to a quadrotor unmanned plane control method based on a fuzzy expansion state observer and an adaptive sliding formwork. The method comprises steps that a quadrotor unmanned plane system model is established, and a system state and controller parameters are initiated; a tracking differentiator is designed; a non-linear expansion state observer is designed; fuzzy rules are established; a parameter adaptive law is designed; an adaptive sliding formwork controller is designed. According to the method, the expansion state observer is designed to estimate indetermination of a system model and external disturbance; a pole assignment method is utilized to determine an initial value of an expansion state observer parameter; the fuzzy rules are introduced to realize online setting for the expansion state observer parameter; the parameter adaptive law is designed to acquire ideal controller gain; the adaptive sliding formwork controller is designed, rapid stabilization of a system tracking error and convergence to a zero point are guaranteed, and rapid and stable position tracking and pose adjustment of the quadrotor unmanned plane are realized. The method is advantaged in that system performance is improved, and rapid and stable system position tracking and pose adjustment are realized.
Owner:ZHEJIANG UNIV OF TECH

Method and device for tracking error propagation and refreshing a video stream

A method and device for tracking error propagation and refreshing a video stream is provided. The proposed subject matter comprises of an error propagation tracking method that works in the sub-sampled domain to reduce computational cycles and memory bandwidth. Further, the tracking based update of the error propagation metric is done differently for static and non-static regions to avoid unnecessary refresh of static areas. Through suitable thresholding of the metric at a macroblock (MB) level, a set of refresh MBs are selected for each frame. These refresh MBs are coded either as an intra MB or as an inter MB that is predicted from one or more reliable reference frames (—frames that are known to be available at the decoder with negligible errors—). Such inter coding of refresh MBs improves the compression efficiency when compared to pure intra coding of refresh MBs. Further, variants to the threshold selection are presented that result in temporally uniform distribution of the number of refresh MBs and a strict refresh scheme wherein all MBs are guaranteed to be with negligible errors following a packet loss within a committed refresh period. In addition, to using the error propagation metric, spatial connectivity to already chosen refresh MBs is used in the selection of additional refresh MBs within a frame and across frames; this reduces the rate of error propagation due to part of a macroblock predicting from older, erroneous neighboring MBs and in turn requiring more refresh MBs on the average per frame.
Owner:ITTIAM SYST P

Method for controlling rigid spacecraft for target attitude tracking

The invention relates to a method for controlling a rigid spacecraft for target attitude tracking, and belongs to the technical field of the high-precision and high-stability attitude tracking control of spacecrafts. The method solves the problem that when the attitude tracking spacecraft runs in a low orbit in outer space, the conventional control method cannot eliminate the inherent flutter of a sliding mode variable structure. The method comprises the following steps: 1, establishing a kinetic model and a kinematic model of the rigid spacecraft; 2, setting an attitude tracking error and anexpected attitude parameter of the rigid spacecraft, and combining the attitude tracking error and the expectation attitude parameter with the kinetic model and the kinematic model to establish a mathematical model for the attitude tracking; 3, adopting a control algorithm of a sliding mode variable structure controller to adjust a control law of the mathematical model which is established in thestep 2 and is used for the attitude tracking, and simultaneously combining an observation result of a disturbance observer to modify the control law; and 4, controlling the rigid spacecraft by using the modified control law obtained in the step 3 to realize the attitude tracking. The method is suitable for the attitude tracking of targets running in the outer space.
Owner:HARBIN INST OF TECH

Direct torque control system of permanent magnet synchronous motor based on terminal sliding mode

The invention discloses a direct torque control system of a permanent magnet synchronous motor based on a terminal sliding mode, which belongs to the field of motor control. The system comprises a main circuit, a signal detection circuit, a rotational-speed outer-ring controller for the terminal sliding mode, a torque linkage inner-ring controller for an adaptive fuzzy sliding mode, a stator-linkage electromagnetic torque estimation module, an SVPWM module, a 3/2 coordinate transform module, and a rotor position/speed estimation module; the design on the rotational-speed outer-ring controller is realized by using a terminal sliding mode control method based on the adaptive estimation of load disturbance, and the rotational-speed outer-ring controller outputs direct-torque controlled demand signals; and the design on the torque linkage inner-ring controller is realized by using an adaptive fuzzy sliding mode control method, and the torque linkage inner-ring controller outputs two-phase alternating voltages in a two-phase stationary coordinate system; and through carrying out SVPWM transformation on the two-phase alternating voltages, a power switching element acted on an inverter of the main circuit implements the direct torque control of the permanent magnet synchronous motor. The direct torque control system in the invention has the advantages of quick torque response speed, good robustness, small tracking error, and capability of improving the reliability and static/dynamic characteristics of the system.
Owner:CHANGCHUN UNIV OF TECH

Antenna beam tracking device and method of moving communication satellite communication system

The invention discloses antenna beam tracking device and method of a moving communication satellite communication system. The antenna beam tracking device comprises a geographical position detection device, a carrier gesture detection unit, a signal intensity detection unit, a signal conditioning circuit and a master control computer, wherein the master control computer controls a servo driver; and the servo driver controls an azimuth and pitching motor. The antenna beam tracking method comprises the following steps of: 1, initially capturing a target satellite; 2, tracking: setting initial parameters, storing and updating the initial parameters in real time, generating simultaneous disturbance random vectors, driving disturbance, measuring the intensity of received signals, estimating gradient, determining tracking error signals, regulating antenna beam pointing directions, and judging the received signals; and 3, recapturing. The invention has the advantages of simple design, low cost, system implementation without changing the hardware structure of an original tracking system, easy operation, high tracking accuracy and fast tracking speed and overcomes the defects of inconvenient operation, complex tracking step, lower tracking accuracy and tracking speed, and the like of the traditional method.
Owner:PLA SECOND ARTILLERY ENGINEERING UNIVERSITY

Binary offset carrier signal tracking loop

InactiveCN101826889AImplement separate trackingEliminate Tracking AmbiguitySatellite radio beaconingPhase-modulated carrier systemsDiscriminatorIntermediate frequency
The invention discloses a binary offset carrier signal tracking loop, which comprises a correlator module, a phase discriminator unit and a filter unit. The correlator module is used for performing demodulation and despread processing on the input intermediate frequency BOC signals, and acquiring multi-path correlation values IIP, IIE, IIL, IQP, IQE, IQL and QIP between local signals and the intermediate frequency BOC signals; the phase discriminator unit is used for detecting the tracking error theta of the carrier phase and the subcarrier phase and measuring the tracking error tau of the spreading codes; and the filter unit is used for performing noise reduction and smoothing on the phase demodulation result, converting the output tracking error into corresponding frequency control words, correspondingly feeding the frequency control words back to the correlator module, tracking the input intermediate frequency BOC signals, and closing the tracking loop. The binary offset carrier signal tracking loop realizes the split tracking of the subcarrier and spreading codes, eliminates the tracking fuzziness of the BOC signals, reduces the requirement on the acquisition precision, improves the tracking performance of weak signals, widens the dynamic range of the loop, and improves the tracking stability of the BOC signals by using the periodicity of the subcarrier.
Owner:BEIHANG UNIV

Trajectory tracking control method used for driverless vehicle

The invention discloses a trajectory tracking control method used for a driverless vehicle. The method includes the following steps that the current position point of a vehicle body is confirmed according to a reference trajectory; a matching point nearest to the current position point of the vehicle is found, and the road curvature of the nearest matching point is obtained according to a two-point curvature obtaining method; according to the current position point of the vehicle and the nearest matching point, a trajectory tracking error is obtained through calculation and comprises a transverse error and a head pointing error; a dynamic model feeding back cornering force on the basis of front wheels is established, and the optimal feedback control rate is obtained by the adoption of an LQR control algorithm; and the cornering force of the front wheels is determined, a front wheel slip angle is obtained on the basis of a reverse tire model, and then the steering wheel angle controlledquantity is obtained and issued to a steering-by-wire system to achieve trajectory tracking control. By the adoption of the method, the stability of trajectory tracking control of the driverless vehicle is improved, the trajectory tracking accuracy is improved, the tire slip angle is restrained, and the possibility that the tire force of the vehicle is saturated under an extreme working conditionand therefore the vehicle loses stability is avoided.
Owner:HUBEI UNIV OF AUTOMOTIVE TECH

Slip form fault-tolerant control method for multi-agent tracking system with executor and sensor faults

The invention discloses an active fault-tolerant control method for a lienar multi-agent tracking system on the basis of slip form control. A distributed fault-tolerant control strategy is put forwardby a distributed observer and a slip form control method by considering the executor faults, the sensor faults, the inherent nonlinearity and the leader unknown control input of a general linear multi-agent tracking system. Firstly, a state tracking error system is established by aiming at each follower, and a sensor fault signal is taken as an auxiliary state amount to establish an augmented tracking error system. In order to simultaneously estimate various faults and the leader unknown control input, an intermediate variable is imported. On the basis of neighbor set output information, a distributed observer is designed for the augmented tracking error system and the intermediate variable, and a global estimation error system is proved to be finally uniformly bounded. According to the obtained observation information, a nonlinear slip form surface is designed for the tracking error system of each follower agent, system robustness is enhanced, and the stability of a sliding mode is proved. According to the fault observation information and the neighbor set output information, a distributed slip form controller is put forward, the state of the error system is guaranteed to reach and be kept at the slip form surface within limited time, and therefore, the fault-tolerant tracking stability of the multi-agent system is realized. The method is used for the fault-tolerant control of the linear multi-agent tracking system with executor faults and sensor faults.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Accurate track tracking control method based on finite time expansion state observer

ActiveCN108828955AOvercome limitationsPrecise track tracking control performanceAdaptive controlKinematics equationsMathematical model
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.
Owner:DALIAN MARITIME UNIVERSITY

Control method for motion stability and outline machining precision of multi-shaft linkage numerical control system

ActiveCN102681489AAchieve smooth motionRealization errorNumerical controlFuzzy pid controlControl system
The invention discloses a control method for motion stability and outline machining precision of a multi-shaft linkage numerical control system. The control method achieves control on the motion stability and outline machining errors of the multi-shaft linkage numerical control system by using a compound control mode of multi-shaft parameter module predictive control and non-linear self-adaptive fuzzy proportional-integral-derivative (PID) control. Simultaneously, error module calculating efficiency is improved by building an outline error module, a speed error module and an acceleration error module. By means of performance optimization indexes, tracking errors, outline errors, speed errors and acceleration errors of the system are minimum, and control performance of a multi-shaft servo control system is improved. Multi-shaft parameter module predicative control increment is solved through a simplified calculating module so as to meet real-time requirements of the control system. Robust property of the multi-shaft linkage numerical control system is improved by adopting the non-linear self-adaptive fuzzy PID control method. The control method effectively improves the motion stability and outline machining precision of the multi-shaft linkage numerical control system.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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