44 results about "Zero-order hold" patented technology

The invention discloses a nonlinear multi-time-scale delay system modeling and control method and belongs to the technical field of controlling of complex systems. The method is based on the UDTTDFSPM and combined with a spectral norm and linear matrix inequality method, a robust combination controller is designed for controlled NMTSTDSs, and high-precision and stable control of the NMTSTDSs is achieved. According to a dynamic model of the NMTSTDSs, an uncertainty continuous time delay obscurity singular perturbation model of the NMTSTDSs is set up, a proper sampling period is selected, a zero-order holder method is adopted to perform discretization on the obtained continuous model, and the UDTTDFSPM of the NMTSTDSs is obtained. The robust combination controller is designed on the basis and is composed of an obscurity slow state feedback controller and an output integrator. The nonlinear multi-time-scale delay system modeling and control method has the advantage of solving the problem of steady-state errors which are caused by system external disturbance and the fast modality of the NMTSTDSs and cannot be solved by an existing modeling and control method, and the control performance of the NMTSTDSs is greatly improved. The nonlinear multi-time-scale delay system modeling and control method is used for controlling the simulation result of postures of a CE150 helicopter, and validity of the method can be shown.

The invention relates to a Markov jump based distributed event triggered filtering system and a design method thereof. The system comprises N filtering links, and is characterized in that each filtering link comprises a sensor, an event trigger, a zero-order retainer and a filter which are sequentially connected, the sensors are connected with a measured object, the filter in each filtering link further performs communication connection with the other neighbor filters, the communication topology among the N filters in the system is of a non-homogeneous Markov jump mode, the mutually connected filters perform information exchange under each type of non-homogeneous Markov link topology, and the filter in each filtering link is further connected with the corresponding event trigger in the filtering link. Compared with the prior art, the Markov jump based distributed event triggered filtering system has good anti-noise capacity, effectively reduces the number of data transmission times under the premise of ensuring the filtering performance and saves network resources.

A switched-current oscillator having a dc current source adapted to charge a capacitor so that the capacitor charging time is controlled based on a sequence of (pseudo)randomly selected values, each of those values defining a corresponding charging time. A discharge device is adapted to discharge the capacitor if the voltage across the capacitor reaches a threshold voltage, at which point the next value in the sequence is selected to determine the next charging time. A square-wave clock signal having spread-spectrum characteristics is generated in the oscillator by using the series of charge-discharge cycles corresponding to the sequence of randomly selected values to toggle a flip-flop operating as a delay line and zero-order hold.

The invention discloses a transverse dynamic control method for an intelligent car in the driving process based on driver characteristics. The transverse dynamic control method comprises the followingsteps that step 1, a two-degree-of-freedom car dynamics model is established as a reference model; step 2, a driver model reflecting the operating characteristics of a driver is established; step 3,a pre-targeted link is established; step 4, a closed-loop control system is established according to the reference model, the driver model and the pre-targeted link; step 5, a zero-order holder is used for discretizing the established closed-loop control system; step 6, a least square identification function is established; and step 7, the loss function for minimizing the position of the car is used as a target, the pre-targeted time is determined according to the delay time and the inertia time, the pre-targeted distance is determined through the preview time, and then the delay time and theinertia time are calculated iteratively, so that the purpose of dynamically determining all parameters is achieved. According to the transverse dynamic control method for the intelligent car in the driving process based on the driver characteristics, the consistency of the models during path following is ensured, and meanwhile, the riding comfort is improved.

A feedforward control system using a polynomial formula not affected by discretization error is realized in a magnetic disk drive. In one embodiment, the magnetic disk drive is intended to move a head for performing at least one of recording and playback to and from a magnetic recording medium to a target position. The feedforward input has a seek control system computed by a polynominal formula of a time function. The coefficients of the polynomial formula have been derived from boundary conditions including the characteristics of a zero-order hold.

Disclosed is a modeling and control method for a complex circuit system with small inductances or capacitances (CCSWSIOCs) and the method belongs to the technical field of complex-circuit-system control. The method is based on an UDTFSPM (uncertain discrete time fuzzy singularly perturbed model) and combines methods of spectral norm and linear matrix inequalities to design an RFSOFC (robust fuzzy static output feedback controller) for controlled CCSWSIOCs so as to realize high-precision control of the CCSWSIOCs. According to a dynamical model of the CCSWSIOCs, an uncertain continuous-time fuzzy singularly perturbed model is established. An appropriate sampling period is selected and a zero-order holder method is employed to perform discretization on the continuous-time fuzzy singularly perturbed model so as to obtain the UDTFSPM of the CCSWSIOCs and thus the RFSOFC is designed on the basis. The advantages of the method are that problems of incapability of elimination of instability or large steady-state errors resulted from the internal minute inductances or capacitances of the CCSWSIOCs in the prior modeling and control methods are solved and control performance of the CCSWSIOCs is improved significantly. The modeling and control method for the complex circuit system with the small inductances or capacitances is applied to precision control of a Van der Pol circuit system to perform simulation verification and validity of the method is shown.

The invention provides an electric motor control device and sets best gain reduction for the input signals provided to the recognition operation. The invention comprises zero holding components (26, 27) for the periodical sampling and maintaining, delay components (28, 29) for the first sampling periodical delaying for the output signals of the zero holding components, multipliers (30, 31) for the reduction of the output signals of the delay components, a regression vector generation part (33) for the regression vector generation by adopting the output signals of the multipliers as the input, a discrete system parameter estimation part (34) for the discrete estimation of the parameter vectors by adopting the regression vector as the input and an automatic gain control part (32) which adopts the output signals of the zero holding components (26, 27) as the input signals and outputs the gain set values of the multipliers.

Techniques for performing digital-to-analog conversion with first-order or higher-order hold using a simple analog circuit for signal reconstruction and employing feedback control techniques are described. In one design, a digital-to-analog conversion circuit includes an inverse model circuit, a feedback circuit, a zero-order hold (ZOH) circuit, and an analog circuit. The inverse model circuit processes a digital input signal and provides a first digital signal. The feedback circuit receives the first digital signal and an analog output signal from the analog circuit, performs low frequency noise filtering, and provides a second digital signal. The ZOH circuit converts the second digital signal from digital to analog with zero-order hold and provides an analog input signal for the analog circuit. The analog circuit operates on the analog input signal and provides the analog output signal. The analog circuit may be a simple circuit having one or more poles.

The invention discloses an optimal-design-based variable sampling rate re-sampling method, which comprises the following steps of: first over-sampling an input discrete signal, namely, performing L-fold interpolation on the input discrete signal by using an L-fold interpolation filter; then recovering the discrete signal into a continuous signal by using a zero-order holding filter; and finally re-sampling the continuous signal according to conversion requirements. The method has the advantages that: high calculation accuracy and lower calculated amount are ensured; the method is fully digital and discrete; only multiplication and addition operations are required, and typical digital signal processing convolution calculation is performed; the hardware accelerated calculation capability of a digital signal processor (DSP) can be fully utilized; and the various protected data re-sampling requirements are met.

The present invention relates to a dual-loop compound control method of a unified power quality controller (UPQC). The method comprises the following steps of: (1) employing a UPQC topology structurechart of a three-phase three-wire system to establish a mathematical model in a synchronous rotating reference frame; (2) performing double closed-loop voltage control of the UPQC: taking a serial three-phase converter circuit as a voltage source, outputting a compensation voltage with a size being the same as the difference of a load voltage and a power grid voltage and with a direction being opposite to the load voltage and the power grid voltage, and obtaining a sine load voltage through double closed-loop PI control; (3) taking a parallel three-phase converter circuit as a current source,and outputting a compensation current with a size being the same as the difference of a power grid current and a load current value and with a direction being opposite to the power grid current and the load current value; (4) designing a current loop PI, and adding a zero-order holder in a control model; (5) designing a repetitive controller: establishing a transfer function of the repetitive controller; and (6) combining a PI control inner loop and a repetitive controller outer loop to perform recombination coordination control, tracking a current compensation instruction, outputting the compensation current, and indirectly controlling a power grid input current as a sine current. The dual-loop compound control method of the unified power quality controller can effectively improve the traceability and the compensation performance.

The invention discloses a control method for reducing the impact on an LCL-type grid-connected inverter from digital control time delay, and the method comprises the steps: 1, carrying out PWM instant loading modulation; 2, connecting a first-order high-pass link (HPF) in a capacitor current negative feedback loop in a series manner, wherein the output of the first-order high-pass link to be overlapped with the output of a controller Gc(s). The PWM loading half-beat time delay in the digital control is eliminated at step 1, and the zero-order holder half-beat time delay of a capacitor current negative feedback inner loop at a resonant frequency band is compensated at step 2. The compatibility of the resonant frequency of the LCL-type grid-connected inverter with the control frequency is improved through steps 1 and 2. The invention proposes the scheme: PWM instant loading + HPF compensation control, thereby eliminating the PWM loading half-beat time delay, achieving the compensating for the time delay of an active damping inner loop at the resonant frequency band, and improving the compatibility of the switching frequency with the resonant frequency of the LCL-type grid-connected inverter and the system stability margin.

In a motor driving device where a motor having a winding wire with small inductance value is driven by a digital control means comprised of control means including a current command value calculating means, a current control means and a PWM control means whose sampling periods are different from each other, when discrete signals sampled by the respective control means are zero-order-held, a motor current includes a lot of higher harmonic waves due to a quantization error, thereby increasing a motor noise. When an n-th-order hold means is provided between the respective control means with different sampling periods, the quantization error can be reduced remarkably, and thus the higher harmonic wave components included in the motor current are reduced, thereby greatly reducing the motor noise.

The invention discloses a ship path tracking event trigger control method based on a zero-order holder. The method comprises the following steps: storing a ship state vector, a control law and an adaptive law at a previous trigger moment by using the zero-order holder; and constructing a concise event triggering mechanism according to the acquired ship state information and the ship state information stored in the zero-order holder. When an event triggering mechanism is satisfied, the system outputs the ship state vector, the control law and the adaptive law stored in the zero-order holder. When the event triggering mechanism is not met, the controller is triggered, and the ship state vector, the control law and the adaptive law stored in the zero-order holder are updated and outputted. Therefore, the problems of communication channel blocking and actuator faults in ship path tracking control are solved through a fault-tolerant mechanism based on event triggering.

The invention provides a left-growth double-edge UPWM (Uniform-sampling Pulse Width Modulation) signal frequency spectrum estimation method based on a digital PWM generator. The method comprises the steps of: performing discretization and quantization of a left-growth double-edge second-level UPWM signal output by a digital PWM generator on a time domain to obtain a series of discrete points; adopting the distribution rule of the amplitudes of the obtained discrete points, performing discrete Fourier transform for the discrete points, and multiplying a transform result by the frequency response function of a zero-order keeper, so that a left-growth double-edge second-level UPWM signal spectrum estimation expression is obtained. The second-level UPMW signal spectrum estimation expressions obtained by modulating the input signals of the digital PWM generator before and after the inversion of the input signal are subtracted to obtain a corresponding third-level UPWM signal spectrum estimation expression. The method provided by the invention can directly obtain the frequency spectrum of the left-growth double-edge UPWM signal under the condition that the input modulation signal is a digital signal.

The invention relates to a multifunctional signal generator device, and discloses a multifunctional signal generator correction method and a multifunctional signal generator, wherein multifunctional signal generator comprises a main control unit, an FPGA unit and a DAC unit. The method comprises the following steps: transmission of wavetable data: a main control unit sends the wavetable data and configures the frequency of the wavetable data, and transmits a wavetable file and the frequency to the FPGA unit; and correction of the waveform data: the FPGA unit stores and reads the received wavetable data, corrects the wavetable data through an amplitude-frequency correction algorithm, and transmits the corrected waveform data to the DAC unit. According to the zero-order retention characteristic of the DAC, the amplitude correction is carried out before the digital signal is input into the DAC, so that the amplitude-frequency distortion is corrected, and the amplitude-frequency characteristic of the output signal of the multifunctional signal generator system is greatly improved.

An apparatus and a method for inverter control are disclosed. A method according to an embodiment of the present invention comprises: discretizing, in a continuous time domain, a voltage equation for a motor in a stationary coordinate system in which a zero-order hold and time delay is reflected; and determining a voltage equation for the motor in a synchronous coordinate system in a discrete time domain by reflecting the position and speed of a rotor of the motor.

The invention belongs to the technical field of integrated circuit design modeling, particularly discloses an s-domain model of an integrated frequency-modulated continuous wave digital frequency synthesizer, and provides a frequency-based modeling method. By using an accumulator model, a pulse switch, a charge pump and an on-chip capacitor are modeled; through the combination of an analog integrator, an ideal sampler, a zero-order retainer, a quantizer and a differentiator, a digital frequency converter is modeled, so that the prediction accuracy of the model is greatly improved; a normalized gain module expression is deduced, so that the model can carry out accurate prediction only by virtue of the accuracy of time-to-digital converter, loop bandwidth and crystal frequency during frequency error and phase noise prediction. The s-domain model can accurately predict the frequency error of a frequency-modulated continuous wave produced by the frequency synthesizer, and the phase noise of dot frequency.

The invention relates to a tactile communication fault tolerance method and system based on hybrid prediction, and the method comprises the steps: carrying out the prediction compression of to-be-transmitted data during the transmission of data, and only transmitting a data frame with the relative deviation between a prediction value and a real value greater than a dead zone parameter, so as to reduce the amount of data needing to be transmitted; when the data is received, if missing data is encountered, adding 1 to the count, comparing the current count value n with a previously received prediction threshold L, if n is greater than L, predicting the missing data by adopting a zero-order preserving prediction algorithm, and otherwise, predicting the missing data by adopting an LSTM model;and if the data is received, resetting the count value, and obtaining a newly received prediction threshold L while the prediction value is a real value. By setting the continuous prediction threshold, the receiving end can autonomously select a relatively conservative prediction algorithm, the influence brought by accumulated errors caused by continuous prediction is reduced, and the stability ofthe tactile communication system is further improved.