Topic
Zero-order hold
About: Zero-order hold is a research topic. Over the lifetime, 367 publications have been published within this topic receiving 4176 citations.
Papers published on a yearly basis
Papers
TL;DR: This paper considers systems with sampled measurements and with control applied through a zero-order hold, under the assumption that the system is stabilizable under sampled-data feedback for some sampling period, and construct sampled- data feedback laws that achieve global asymptotic stabilization under arbitrarily long input and measurement delays.
Abstract: Sampling arises simultaneously with input and output delays in networked control systems. When the delay is left uncompensated, the sampling period is generally required to be sufficiently small, the delay sufficiently short, and, for nonlinear systems, only semiglobal practical stability is generally achieved. For example, global stabilization of strict-feedforward systems under sampled measurements, sampled-data stabilization of the nonholonomic unicycle with arbitrarily sparse sampling, and sampled-data stabilization of LTI systems over networks with long delays, are open problems. In this paper, we present two general results that address these example problems as special cases. First, we present global asymptotic stabilizers for forward complete systems under arbitrarily long input and output delays, with arbitrarily long sampling periods, and with continuous application of the control input. Second, we consider systems with sampled measurements and with control applied through a zero-order hold, under the assumption that the system is stabilizable under sampled-data feedback for some sampling period, and then construct sampled-data feedback laws that achieve global asymptotic stabilization under arbitrarily long input and measurement delays. All the results employ “nominal” feedback laws designed for the continuous-time systems in the absence of delays, combined with “predictor-based” compensation of delays and the effect of sampling.
274 citations
14 Jun 2006
TL;DR: In this paper, the extended state observer (ESO) is reformulated using a generalized disturbance model, which provides a wider range of solutions for disturbance estimation problems and is shown on a realistic motion control simulation platform with favorable results.
Abstract: A brief review of developments in disturbance observers, leading up to the extended state observer (ESO), is first presented. Various digital implementations of the ESO are investigated and compared. The realization in current discrete estimator form evidently helps to maintain stable operation at low sampling rates. Digitization using zero order hold is derived symbolically to further improve accuracy while preserving the simplicity of single parameter tuning. Finally, the ESO is reformulated using a generalized disturbance model which provides a wider range of solutions for disturbance estimation problems. Application of the proposed algorithm is shown on a realistic motion control simulation platform with favorable results.
208 citations
Patent•
20 Jan 1998TL;DR: In this article, an asynchronous sample rate converter for converting a first sample rate in a signal to a second sample rate of the same signal is presented, where the signal is first provided as input to an interpolator which upsamples the signal to form a signal having sample rate UFs1 where the upsampling factor U is a variable that is directly related to the ratio Fs2/Fs1.
Abstract: An asynchronous sample rate converter for converting a first sample rate in a signal to a second sample rate in the same signal is presented. The signal is first provided as input to an interpolator which upsamples the signal to form a signal having sample rate UFs1 where the upsampling factor U is a variable that is directly related to the ratio Fs2/Fs1. The resampler then linearly interpolates the upsampled signal to form a signal having sample rate DFs2. Finally, the resampled signal is downsampled to form a signal having sample rate Fs2.
135 citations
Patent•
5 Nov 1997
TL;DR: In this paper, an active pixel sensing structure includes an array of pixel unit cells each of which is adapted to alternate between a light sensing mode and a reset mode wherein the cell outputs a reset signal.
Abstract: An active pixel sensing structure includes an array of pixel unit cells each of which an adapted to alternate between a light sensing mode wherein the cell outputs an image signal and a reset mode wherein the cell outputs a reset signal. The image signal is proportional to light incident on the cell, and the reset signal is proportional to a predefined reference potential. An improved readout circuit according to the present invention includes a first sample and hold component for receiving and storing the image signal, and second sample and hold component for receiving and storing the reset signal. A signal amplifier is provided for each sample and hold component. A switching circuit is operable between a first mode and a second mode. In the second mode, the first and second sample and hold components are operatively decoupled from the corresponding signal amplifiers while input terminals of the signal amplifiers are connected to a source of predetermined reference potential. With the switching circuit in the second mode, fixed pattern noise (FPN) attributable to the amplifiers is determined. With the switching means in the first mode, a voltage, D2, is determined across outputs of the signal amplifiers. The voltage, D2, is proportional to a voltage equal to the difference between the image signal and the reset signal plus the FPN voltage. A processing means subtracts the voltage, D1, from the voltage, D2, to develop a signal proportional to the light detected by the cell.
125 citations
TL;DR: In this paper, a small-gain theorem can be applied to a wide class of systems that include systems satisfying the weak semigroup property, which generalizes all existing results in the literature and exploits notions of weighted, uniform, and nonuniform input-to-output stability properties.
Abstract: A small-gain theorem, which can be applied to a wide class of systems that includes systems satisfying the weak semigroup property, is presented in the present work The result generalizes all existing results in the literature and exploits notions of weighted, uniform, and nonuniform input-to-output stability properties Applications to partial state feedback stabilization problems with sampled-data feedback applied with zero order hold and positive sampling rate are also presented
110 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 3 |
| 2020 | 1 |
| 2019 | 4 |
| 2018 | 2 |
| 2017 | 6 |
| 2016 | 10 |