Integral Gain Research Articles

Motion Parameter Estimation and HRRP Construction for High-Speed Weak Targets Based on Modified GRFT for Synthetic-Wideband Radar With PRF Jittering

The synthetic-wideband and pulse repetition frequency jittering radar systems are receiving increasing attention due to the relatively low construction costs and good anti-jamming performance. However, the inter-pulse random hopping of the carrier frequency and pulse repetition frequency introduces challenges to the long-time coherent integration and motion parameter estimation of the high-speed weak targets for these radar systems. A modified generalized Radon Fourier transform for weak target detection and motion parameter estimation is proposed. The proposed method can achieve full coherent integration gain for the high-speed weak target and has a good parameter estimation accuracy. After the target motion has been well compensated, the well-focused high-resolution range profile of the target can be obtained by synthetic-wideband processing. The effectiveness of the proposed method is verified by Monte Carlo simulations. In addition, experimental data collected using an X-band radar system are processed and analyzed to illustrate the practical performance of the proposed method.

GAMMA: A 16-Channel Spectroscopic ASIC for SiPMs Readout With 84-dB Dynamic Range

Gain amplitude modulation multichannel ASIC (GAMMA) is a 16-channel application specified integrated circuit (ASIC), designed in 0.35- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> technology to read the charge provided by silicon photomultipliers (SiPMs) on a wide amplitude range. This chip was designed to satisfy the demanding requirements of the INFN the GAMMA project, where a 3” <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times3$ </tex-math></inline-formula> ” large lanthanum bromide crystal is to be read by SiPMs, aiming at state-of-the-art energy resolution. Because the energy range of the application is 100 keV–20 MeV, signals in a wide dynamic range (DR) have to be processed by the ASIC. This wide DR requirement raised the necessity of an adaptive gain change solution in order to guarantee a high signal-to-noise ratio together with a large full-scale range. While the ASIC input stage features a programmable static gain, the analog filtering channel exploits a self-triggered gated integrator stage with an automatically adjusted gain for each detected input current pulse; one of the following values is selected: 10, 2, or 0.83 [mV/pC]. The gated integrator gain is predictively adjusted before the circuit reaches saturation due to a time-gated threshold mechanism and provides negligible charge loss when the gain is switched (< 20 fC). A preintegration feature is also implemented in order to get rid of nonlinearity due to delays in the integration phase that could take place in a multi-ASIC system. The ASIC uses 5- and 3.3-V bias voltages, the overall power consumption being 280 mW. The ASIC was tested with a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$12\times12$ </tex-math></inline-formula> SiPMs matrix coupled with a 3 inch LaBr <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> , providing good spectroscopic performances (2.6% at the <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">137</sup> Cs photopeak emission energy of 662 keV), and was also tested irradiating the SiPMs with fast, bright NUV light pulses, in order to explore the ASIC wide range coverage while simulating the scintillation light emission of a lanthanum bromide crystal.

AGC Including ELD and Emission Coordination Using Sine Cosine Algorithm

The aim of conventional AGC is to regulate the demand load of the area with taking into account the sharing power with the others area and also the frequency deviation and tie-line power deviation within minimum error steady-state. The proposed coordination's goal is to regulate the demand load between the interconnected area when taking into account the optimal dispatch and emission effect. The two-area that be consist of three units in each one (hydro, thermal, and gas) is used of proposed system. The optimization algorithms were used to find the best operating point of the system by tuning the integral gain are located in ACE that named primary control and Generation allocation logic named secondary controller. The Particle Swarm Optimization (PSO) and Sine Cosine Algorithm (SCA) are used to tune gains of the integral (I) controller to show the superiority in identifying robust controller. The simulation results prove that the SCA with proposed coordination is very effectiveness as compared with PSO algorithm in enhance the dynamic performance and reduce overshoot, maximum frequency deviation, and net tie line power flow deviation error for a given load change and disturbed the demand load between two-area as economic.

Analysis and Design of a Charge Sampler With 70-GHz 1-dB Bandwidth in 130-nm SiGe BiCMOS

This paper investigates an ultra-broadband sampling technique based on charge sampling using an Integrate-and-Hold Circuit (IHC) and ultra-short integration times. The charge sampling technique is mathematically analyzed in detail and compared to conventional switched-capacitor sampling. The mathematical analysis allows to predict the sampler bandwidth as well as the degradation of sampling precision due to analog circuit impairments such as integrator gain error, integration capacitor leakage, hold-mode droop, thermal noise, and clock jitter. Furthermore, design, simulation, and measurement results of an ultra-broadband charge sampler IC in SiGe BiCMOS technology are presented. The charge sampler IC achieves a 1dB bandwidth of 70 GHz. A resolution of better than 5.9 effective number of bits (ENOB) is measured from 0 to 70 GHz at a sampling rate of 5 GS/s. The results suggest that charge sampling using an IHC is a viable concept for ultra-broadband sampling.

Integrating Sensing and Communications for Ubiquitous IoT: Applications, Trends, and Challenges

Recent advances in wireless communication and solid-state circuits together with the enormous demands of sensing ability have given rise to a new enabling technology, integrated (radar) sensing and communication (ISAC). ISAC captures two main advantages over dedicated sensing and communication functionalities: integration gain to efficiently utilize congested wireless/hardware resources, and even more interesting, coordination gain to balance dual-functional performance or/and perform mutual assistance. Triggered by ISAC, we are also witnessing a paradigm shift in the ubiquitous IoT architecture, in which the sensing and communication layers are tending to partially converge into a new layer, namely, the signaling layer. In this article, we first attempt to introduce a definition of ISAC, analyze the various influencing forces, and present several novel use cases. Then we complement the understanding of the signaling layer by presenting several key benefits in the IoT era. We classify existing dominant ISAC solutions based on the layers in which integration is applied. Finally, several challenges and opportunities are identified. We hope that this overview article will serve as a primary starting point for new researchers and offer a bird's-eye view of the existing ISAC-related advances.

Optimized four-parameter PID controller for AVR systems with respect to robustness

A procedure for the optimization of the proportional-integral-derivative (PID) controller under constraints to robustness of model uncertainties and sensitivity to measurement noise for a synchronous generator (SG) automatic voltage regulator (AVR) is presented in this paper. Performance indices related to the load disturbance response such as integral error (IE) and integral absolute error (IAE) are used as key criteria for the design method. They are minimized for a given maximum modulus of sensitivity function Ms. By maximizing loop gain regarding given sensitivities Ms and Mn we optimized load disturbance response. Contrary to majority AVR PID controller procedures, along with proportional, integral and derivative gain, a noise filter time constant is included in a proposed optimization algorithm to satisfy given sensitivity to the measurement noise Mn. A simple and effective solution of the optimization problem is obtained by binding a ratio between the integral and the derivative time constant Ti/Td. The optimal Ti/Td ratio is determined subsequently. Besides this, a step response to voltage reference change is modified with a reference filter to avoid large overshoots. This is achieved by limiting the maximum modulus of the resulting close-loop transfer function sensitivity Msp. The fact that zeros and poles of the second order reference filter have the same damping factor simplifies the procedure for resolving two out of six parameters. Also, two additional conditions result in the fact that three design parameters {Ms, Mn, Msp} are sufficient to determine the required six parameters of the two-degree-of-freedom (2DOF) PID controller. Such controller outperforms recently presented AVR controllers especially regarding the load disturbance rejection. Experiment tests with no-load SG and SG connected on the grid are carried out to prove the claims stated in this work concerning robustness performance and sensitivity to measurement noise. Also, we showed practical use of the proposed controller parameter tuning procedure by experimental runs performed on a lab generator.

Adaptive Real-Time Wavelet Denoising Architecture Based on Feedback Control Loop

The discrete wavelet transform is commonly used as a denoising step for many applications, like biomedical applications which are usually suffering from low SNR of the recorded signal. However, the choice of appropriate threshold value for DWT coefficients plays significant role in reconstructing the denoised signal. This paper presents a design of real-time wavelet denoising architecture which is suitable for wide range of real-time denoising applications. In this design, an adaptive thresholding approach based on feedback control loop is proposed to make the architecture more applicable for real-time wavelet denoising. This thresholding method considers a noise level estimator module based on first detail coefficients level 𝑑1 to calculate the unknown standard deviation of background noise. The proposed architecture is developed using MATLAB to simulate the suggested denoising method. The performance of the proposed denoising method is studied in terms of integral gain 𝐺 of feedback control and window size 𝑀 with respect to the improvement in SNR and settling time. The results imply that the proposed denoising architecture is suitable for real-time denoising applications with acceptable improvement in SNR approximately 8 dB.

Ultrastructural features of the corneal epithelium with micromolecular compound J2 in the corneal allograft of rats using atomic force microscopy

Objective: To study the ultrastructural features of the corneal epithelium in the corneal allograft of rats with micromolecular compound J2. Methods: An experimental study. Primarily cultured corneal epithelial cells of rats were used. Mononuclear cells (MNCs) by density gradient centrifugation were assigned into the experimental group [MNCs (2 ml)+corneal epithelial cells+J2], control group [MNCs (2 ml)+corneal epithelial cells] and blank group (corneal epithelial cells). Quantity of CD80 expression was obtained by flow cytometry after coculture. Amplitude and height images were obtained by tapping mode atomic force microscopy (AFM) with a scan rate of 2 Hz and an integral gain of 0.3 to 0.5. Statistical analysis of Ra, Rq, Rvm and Rt was performed using the single-factor analysis of variance, and P value was calculated. Results: There were obvious differences in the ultrastructure measured by AFM among groups. Ra was 86.75±12.60 in the experimental group, 120.23±12.11 in the control group, and 61.94±10.62 in the blank group (F=306.92, P<0.01). Rq was 102.53±9.45, 138.30±10.13, and 91.96±7.25, respectively, in the three groups (F=361.85, P<0.01). Rvm was -42.21±14.22, -67.36±10.89, and -32.18±19.01, respectively (F=72.22, P<0.01). Rt was 437.32±15.66, 495.32±13.96, and 339.92±11.22, respectively (F=1634.26, P<0.01). The one way analysis of variance showed significant differences in these parameters among groups. Conclusions: Corneal epithelial cells of rats activated by MNCs had higher CD80 expression, but the expression became decreased with micromolecular compound J2. The ultrastructure of the corneal epithelium became coarser after MNCs activation, and the number of protrusions increased significantly. The ultrastructural changes were alleviated by J2.(Chin J Ophthalmol, 2021, 57: 608-613).

Proportional integral observer based tracking control design for Markov jump systems

With the use of proportional integral observer, this article intends to discuss an effective output tracking control and disturbance rejection problem for an input time-delayed Markov jump system with state dependent nonlinearities and randomly occurring uncertainties. Notably, the proportional integral observer incorporates both proportional and integral loop, where the presence of additional loop provides unbiased state estimation. Moreover, an improved equivalent input disturbance approach with a gain factor is considered to enhance better disturbance estimation and rejection performance. Naturally, Smith predictor is commenced to handle input time delays. Subsequently, the combination of improved equivalent input disturbance with Smith predictor guarantees the desired tracking performance with input time delays and external disturbances. By endowing Lyapunov stability theory, a set of sufficient conditions is developed in the frame of linear matrix inequalities to promise the asymptotically stability of the closed-loop system. Subsequently, the explicit form of the desired proportional integral gain matrices are parameterized using the matrix inequality techniques. The superiority of our proffered control technique are validated through two numerical examples, which includes a practical model namely RLC circuit.

Fixed-Time Synergetic Control-Based Chaos Suppression for Eighth-Order IFOCIM Drive System

This paper investigates chaos suppression in widely used indirect field oriented controlled induction machine (IFOCIM) drive system using fixed-time synergetic control method. The complex eighth-order IFOCIM drive system shows chaotic oscillations during a specific range of the integral gain of the PI speed controller. The conventional synergetic control method is improved by employing the fixed-time theory, the characteristics of the designed controller are chattering free and the convergence time is limited within a fixed-time upper bound depending on the controller parameters. The fixed-time synergetic control method is used to converge a selected macro variable to the origin within the fixed time upper bound. The controller can stabilize the chaotic system dynamics in a good way within a short time.

Effects of Artificially Reproduced Fluctuations in Sunlight Spectral Distribution on the Net Photosynthetic Rate of Cucumber Leaves.

The effects of photosynthetic photon flux density (PPFD) fluctuations in sunlight have already been investigated; however, the spectral photon flux density distribution (SPD) has hardly been considered. Here, sunlight SPD fluctuations recorded for 200 min in October in Tokyo, Japan were artificially reproduced using an LED-artificial sunlight source system. The net photosynthetic rate (Pn) of cucumber leaves under reproduced sunlight was measured and compared with the Pn estimated from a steady-state PPFD–Pn curve for the same leaves. The measured and estimated Pn agreed except when the PPFD was low, where the measured Pn was lower than the estimated Pn. The ratio of measured Pn to estimated Pn was 0.94–0.95 for PPFD ranges of 300–700 μmol m–2 s–1, while the value was 0.98–0.99 for 900–1,300 μmol m–2 s–1, and the overall ratio was 0.97. This 3% reduction in the measured Pn compared with the Pn estimated from a steady-state PPFD–Pn curve was significantly smaller than the approximately 20–30% reduction reported in previous experimental and simulation studies. This result suggests that the loss of integral net photosynthetic gain under fluctuating sunlight can vary among days with different fluctuation patterns or may be non-significant when fluctuations in both PPFD and relative SPD of sunlight are taken into consideration.

Digital Control of a Stepping Motor for Eliminating Rotation Speed Fluctuations Using Adaptive Gains

Nowadays, stepping motors are usually used as precise actuators in various new scientific fields, such as syringe pumps, blood analyzers, and bio-3D printers. Controlling rotation of the stepping motor without speed fluctuation under no-load conditions plays an important role in improving the accuracy of the machine’s drive. This paper proposes a digital control method for a five-phase hybrid stepping motor. The proposed controller includes an original control loop and a PI adaptive integration gain control loop. The original digital control loop is redesigned from the analog controller by using the direct PIM method. The PI adaptive control loop is added to the original control loop in a parallel way to remove a steady deviation of the motor and suppress a physical saturation factor inside the plant. Lyapunov stability theory is used to prove a stability condition of the PI regulator gains. Experimental results show that the proposed controller can suppress the chattering caused by the switching structure and gives performances as good as that of the commercial analog controller in a high rotation speed range without fluctuation.

Coherent Integration Loss Due to Nonstationary Phase Noise in High-Resolution Millimeter-Wave Radars

Phase noise refers to the instability of an oscillator, which is the cause of instantaneous phase and frequency deviations in the carrier wave. This unavoidable instability adversely affects the performance of range–velocity radar systems, including synthetic aperture radars (SARs) and ground-moving target indicator (GMTI) radars. Phase noise effects should be considered in high-resolution radar designs, operating in millimeter wavelengths and terahertz frequencies, due to their role in radar capability during the reliable identification of target location and velocity. In general, phase noise is a random process consisting of nonstationary terms. It has been shown that in order to optimize the coherent detection of stealthy, fast-moving targets with a low radar cross-section (RCS), it is required to evaluate the integration gain and to determine the incoherent noise effects for resolving target location and velocity. Here, we present an analytical expression for the coherent integration loss when a nonstationary phase noise is considered. A Wigner distribution was employed to derive the time–frequency expression for the coherent loss when nonstationary conditions were considered. Up to now, no analytical expressions have been developed for coherent integration loss when dealing with real nonstationary phase noise mathematical models. The proposed expression will help radar systems estimate the nonstationary integration loss and adjust the decision threshold value in order to maximize the probability of detection. The effect of nonstationary phase noise is demonstrated for studying coherent integration loss of high-resolution radar operating in the W-band. The investigation indicates that major degradation in the time-frequency coherent integration due to short-term, nonstationary phase noise instabilities arises for targets moving at low velocities and increases with range. Opposed to the conventional model, which assumes stationarity, a significant difference of up to 25 dB is revealed in the integration loss for radars operating in the millimeter wave regime. Moreover, for supersonic moving targets, the loss peaks at intermediate distances and then reduces as the target moves away.

Improved DC-Link Voltage Controller for Photo Voltaic ON-Grid Systems

The DC-link voltage is an essential intermediate stage between the DC/DC and DC/AC converters in solar energy system. Due to the voltage fluctuations and current disturbances, a controller should be suitably designed to maintain the DC-link voltage well stabilized. In this paper, a variant of an adaptive DC-link voltage controller is proposed, namely PI-Fuzzy controller. The proposed controller has a fixed integral gain, while the proportional gain is determined based on a set of Fuzzy logic inference rules. Moreover, an anti-windup mechanism is added to the proposed controller to overcome integrator windup when the actuator saturates. Simulation results show that the proposed controller provides better rejection of current disturbances and fastest rise-time comparing to recently proposed PI-controllers for the DC-link voltage control.

Deep neural network based MPPT algorithm and PR controller based SMO for grid connected PV system

ABSTRACT In a grid connected photovoltaic (PV) system, the maximum power will be tracked by the conventional Perturb and Observe (P&O) algorithm. It generally produces high oscillations around maximum power point, and it fails to attain extreme power under prompt environmental conditions. To overcome these issues, this work proposes a deep neural network (DNN) based Maximum Power Point tracking (MPPT) algorithm and PR controller-based SMO for PV grid-connected system. The DNN consists of many algorithms in that here we use RNN in MPPT algorithm for tracking the maximum power. The Recurrent Neural Network (RNN) hidden layer has more number of layers. The deep network weight function is optimised by meta-heuristic-based Bald Eagle Search (BES) Optimisation. The proposed tracked RNN based Maximum Power Point (MPP) is passed through the DC/DC buck-boost converter. The inverter is tuned by Proportional Resonant (PR) controller, and it has two gain parameters like a proportional and integral gain. The PR controller gain parameters are tuned by the global optimisation algorithm of Spider Monkey Optimisation (SMO) to achieve better performance.

IMC Based PID Controllers Retuning and Its Performance Assessment

Internal Model Control (IMC) is the basis of a systematic program Q on the parameters of the concept and is based on the many modern control technology control system design. The present research work presents a novel control scheme for tuning PID controllers using Internal Model control with the filter time constant optimized using Bee colony Optimization technique. The robustness is measured by a two-block structured singular value, and the disturbance rejection is measured by the minimum singular value of the integral gain matrix. PID controllers are used widely in Industrial Processes. Criteria based on disturbance rejection and system robustness are proposed to assess the performance of PID controllers. Tuning of PID controllers is accomplished using Internal Model control scheme. In this paper, we propose an optimal filter design IMC IMC-PID controller for unstable process better set point tracking. IMC includes tuning of filter constant λ. The controller is suitable for different values of the filter tuning parameters to achieve the desired response in due IMC method is based on pole-zero offset, including IMC design principle method causes the response sets a good point. However, in a stable long lag time of load disturbances leading to undesirable process which is the result of the IMC control industry. Therefore, IMC has been a popular design process processing industry, especially as a means for adjusting the single-loop, PID controllers.

Effects of Movement for High Time-Bandwidths in Batched Pulse Compression Range-Doppler Radar.

Radar detection and track building performance is an essential part of a radar system. A high realized coherent integration gain often contributes to an improved performance. This is essential to the successful detection and tracking of weak moving targets. However, the actual movement within the coherent processing interval can introduce range walk effects. The processing will then result in range and Doppler frequency resolutions that become finer than a single moving point scatterer’s spread over range and—often not considered—over Doppler frequency. In particular for a wide instantaneous bandwidth, the impact on the achievable integration gain can become severe already for a constant effective velocity. Therefore, high desired integration gains as required in passive radar are not easily achieved against relatively fast moving targets. The main intent of this article is to present the movement effects on a classical range-Doppler analysis to give an insight on the achievable performance and to quantify otherwise appearing degradations. Interestingly, a classical analysis of experimental datasets evaluated from a DVB-T based passive radar measurement campaign even resolved the fluctuation of a target response within the instantaneously processed bandwidth. The findings strengthen the need for advanced processing methods that can at least partly address individual implications of fast moving targets in real-time applications properly.

Evaluation of the PETsys TOFPET2 ASIC in multi-channel coincidence experiments

BackgroundAiming to measure the difference in arrival times of two coincident γ-photons with an accuracy in the order of 200ps, time-of-flight positron emission tomography systems commonly employ silicon photomultipliers (SiPMs) and high-resolution digitization electronics, application specific integrated circuits (ASICs). This work evaluates the performance of the TOFPET2 ASIC, released by PETsys Electronics S.A. in 2017, dependent on its configuration parameters in multi-channel coincidence measurements.MethodsSiPM arrays fabricated by different vendors (KETEK, SensL, Hamamatsu, Broadcom) were tested in combination with the ASIC. Scintillator arrays featuring different reflector designs and different configurations of the TOFPET2 ASIC software parameters were evaluated. The benchtop setup used is provided with the TOFPET2 ASIC evaluation kit by PETsys Electronics S.A.ResultsCompared to existing studies featuring the TOFPET2 ASIC, multi-channel performance results dependent on a larger set of ASIC configuration parameters were obtained that have not been reported to this extend so far. The ASIC shows promising CRTs down to 219.9 ps in combination with two Hamamatsu S14161-3050-HS-08 SiPM arrays (128 channels read out, energy resolution 13.08%) and 216.1 ps in combination with two Broadcom AFBR-S4N44P643S SiPM arrays (32 channels read out, energy resolution 9.46%). The length of the trigger delay of the dark count suppression scheme has an impact on the ASIC performance and can be configured to further improve the coincidence resolution time. The integrator gain configuration has been investigated and allows an absolute improvement of the energy resolution by up to 1% at the cost of the linearity of the energy spectrum.ConclusionMeasuring up to the time-of-flight performance of state-of-the-art positron emission tomography (ToF-PET) systems while providing a uniform and stable readout for multiple channels at the same time, the TOFPET2 ASIC is treated as promising candidate for the integration in future ToF-PET systems.

Tuning of PID Controller Parameters with Genetic Algorithm Method on DC Motor

Proportional Integral Derivative (PID) controllers are used in general to control a system, for example a DC motor system. The difficulty of using the controller is parameter tuning, because the tuning parameters still use the trial and error method to find the PID parameter constants, namely Proportional Gain (KP), Integral Gain (KI) and Derivative Gain (KD). In this case, the genetic algorithm method is used which can give better results in each iteration. Genetic algorithms are one of the smart methods inspired by the process of natural selection, the process that causes biological evolution, this concept is applied to tuning PID parameters. This research uses the Matlab simulation method and applies the simulation results to the DC motor hardware using the Arduino Uno. The genetic algorithm method gives a system that has a better steady time and a smaller maximum spike than the Trial and Error method. The test process produced the two best data with an overshoot value = 2, settling time = 13.5 and rise time of 2.7872 and the PID parameter value for mutation of 1 was KP = 3.7500; KI = 1.3184 and KD = 0.2051. Then the value of the best PID parameter on Crossover is 0.4, which is KP = 4.2090; KI = 1.2012 and KD = 0.2539 with an overshoot value = 2, settling time = 18 and rise time = 2.6462.

UAV detection via long-time coherent integration for passive bistatic radar

Detection of unmanned aerial vehicle (UAV) is a challenging problem for passive bistatic radar (PBR) because of its low radar cross-section (RCS). Range migration (RM) will occur within one long coherent processing interval, which makes it difficult to increase coherent integration gain and improve radar detection ability. In order to eliminate the RM, a novel coherent integration method based on stretch processing and chirp-z transform (CZT) in the frequency domain is proposed. Firstly, stretch processing is applied to correct RM. Then, CZT is performed to mitigate the residual range offset and achieve coherent integration of the target's energy according to each Doppler cell. The advantage of the proposed method is that it can obtain superior coherent integration and detection performance compared to existing methods. Numerical and experimental results are presented to demonstrate the effectiveness of the proposed method.