Order Low Pass Filter Research Articles

State-of-charge estimation for lithium-ion batteries based on modified unscented Kalman filter using improved parameter identification

The full and single hybrid pulse power characterization (HPPC) experiments are conducted on nickel cobalt manganese (NCM) and lithium iron phosphate (LFP) batteries to obtain the accurate relationship between state of charge (SOC) and open circuit voltage (OCV). The pseudo random number generated by the RAND function is used as the initial value of the parameter identification equation for the second-order equivalent circuit model (ECM), and the parameter identification of lithium-ion batteries is achieved through least squares fitting. The unscented Kalman filter (UKF) simulation model is modified by the first order low pass filtering (FOLPF) algorithm to improve the accuracy of SOC estimation of batteries. The results show that the goodness of fit between the real and estimated HPPC pulse voltage values at different SOC values is above 0.99 for both NCM and LFP batteries. Based on the parameter identification results, the maximum error of the HPPC voltage estimated by the second-order ECM is within 0.045 V under both full pulse and single pulse testing conditions while the maximum error of SOC estimation is within 0.025. The UKF model modified by the FOLPF algorithm provides a reference for the accurate SOC estimation of batteries.

A current mode capacitance multiplier employing a single active element based on Arbel-Goldminz cells for low frequency applications

In this work, a capacitor multiplier based on a Multiple Output-Voltage Difference Transconductance Amplifier (MO-VDTA) is built by using Arbel-Goldminz cells with extensive performance analysis. Considering the large chip area occupation of capacitors, capacitor multipliers are one of the most required analog building blocks in most of low frequency applications. In this respect, the obtained capacitor multiplier is tested in a 2nd order low-pass filter by changing the cut-off frequency from 2 kHz to around 12.4 kHz. The multiplication factor (denoted as “k”) of the proposed architecture can be adjusted electronically from 120 to 750 for approximately two decades, while the structure contains only a single active element with a base capacitance. Additionally, the multiplication factor can be safely increased by using additional transconductance stages in the MO-VDTA active block. In the performance analysis, post-layout results are provided in conjunction with process corners, Monte-Carlo analyses and experimental verifications on the basis of commercial off-the-shelf elements such as AD844 and LM13700s.

Realization of nth Order Wave Active Low-Pass Filter Using Differential Difference Current Conveyor

A wave active filter (WAF) based on a differential difference current conveyor (DDCC) is presented in this paper. An active filter formation depends entirely on wave quantity processing. The wave method is demonstrated for the basic wave active elements (WAEs) of active filters such as a series inductor and a shunt capacitor. The novelty of the proposed work is that the mathematical operations required to implement the wave active components, such as lossy integration-subtraction; subtraction; summation and inverter, are performed using the DDCC as an analog building block (ABB). Designing WAFs of lower to higher-order is extremely challenging, i.e., great motivation to propose a WFA using a CMOS-based DDCC for lower and higher-order low-pass Butterworth filter topologies. Additionally, the filter performances are verified through noise analysis, percentage total harmonic distortion (%THD) and Monte Carlo analysis. The proposed WFA is theoretically verified for [Formula: see text]th order low-pass Butterworth filter designs ([Formula: see text]) using DDCC-based WAEs and validated using SPICE simulations with [Formula: see text]m TSMC CMOS technology parameters for DDCC, operating on [Formula: see text][Formula: see text]V.

Realization of fractional order lowpass filter using different approximation techniques

Many research groups are starting to pay serious attention to the problem of fractional-order circuits. In this paper, a new approach to designing fractional order low-pass filter (FOLPF) is presented. Finding a rational approximation of the fractional Laplace operator sα is a crucial step in the design of fractional order filters. A comparative study of the most widely used approximation techniques named continued fraction expansion (CFE) method and Biquadratic Approximation (RE) method is performed. Then the transfer function of the proposed FOLPF is calculated. Using operational amplifier, the proposed filter is synthesized. The proposed circuit is simulated using Texas instruments TINA software. The results obtained outperform the existing methods.

Novel TIλDND2N2 Controller Application with Equilibrium Optimizer for Automatic Voltage Regulator

Sustainability is important in voltage regulation control in grids and must be done successfully. In this paper, a novel tilt-fractional order integral-derivative with a second order derivative and low-pass filters controller, referred to as TIλDND2N2 controller, is proposed to enhance the control performance of an automatic voltage regulator (AVR). In this article, the equilibrium optimizer (EO) algorithm is used to optimally determine the eight parameters of the proposed controller. In this study, a function consisting of time domain specifications is used as the objective function. To evaluate the performance of the proposed controller, it is compared with the proportional-integral-derivative (PID), fractional order PID (FOPID), PID accelerator (PIDA), PID plus second order derivative (PIDD2), and hybrid controllers used in previous studies. Then, Bode analysis is performed to determine the achievement of the proposed controller in the frequency domain. Finally, the robustness test is realized to assess the response of the proposed controller against the deterioration of the system parameters. As a result, the proposed controller demonstrates outstanding control performance compared to studies in terms of settling time, rise time and overshoot. The proposed controller shows superior performance not only in frequency domain analysis but also in perturbed system parameters.

Design of a Fractional Order Low-pass Filter Using a Differential Voltage Current Conveyor

In this paper, an active implementation of a differential voltage current conveyor (DVCC) based on a low-pass filter operating in the fractional order domain is presented. The transfer function for a fractional order system is dependent on the rational approximation of sα. Different methods used for calculating the rational approximation, including Carlson, Elkhazalil, and curve fitting, are evaluated here. Finally, to validate the theoretical results, a fractional order Butterworth filter is simulated in the Pspice environment using the 0.5 micrometer CMOS technology with an R-C network-based fractional order capacitor. Additionally, using the Monte Carlo analysis, the impact of current and voltage faults on DVCC response is investigated. It has been inferred that realization with a wider bandwidth is possible.

A self-adjusting multi-objective control approach for quadrotors

The quadrotor represents a class of highly nonlinear dynamic systems and its controllability features are challenging. Hence, it serves as an ideal unmanned aerial vehicle platform to validate many artificial intelligence-based research investigations. Nonetheless, most of the offline tuning approaches devote efforts to find near optimal control gains to regulate individually the decoupled motion directions. This work adopts a multi-objective self-adjusting search mechanism to actuate the motions of a quadrotor via deciding the control gains of the interacting loops simultaneously. This algorithm employs a first order low pass filter transfer function as an accepting approach for the tunning mechanism. The proposed approach is compared with a Genetic Algorithm and another nonlinear Proportional-Integral-Derivative approach to highlight the usefulness of the proposed mechanism. It was founded that quadrotor follows the desired trajectory with a small tracking error of less than 2% in the X-Y plane and less than 1 % error tracking error in the altitude Z. Also, it is recorded that MONLTA can overcome the simulated wind disturbances of 0.1 N.m as a disturbance torque.

Resilient Cooperative Output Regulation for Nonlinear Multiagent Systems Under DoS Attacks

The resilient cooperative output regulation problem for a class of uncertain nonlinear multi-agent systems (MASs) under denial-of-service (DoS) attacks is addressed in this paper. This is the first attempt to investigate the cooperative output regulation problem for nonlinear MASs under DoS attacks, and a novel distributed control scheme consisting of a resilient distributed observer and a distributed adaptive controller is proposed. Specifically, a novel resilient distributed observer in the form of an upper triangular chain of first order low pass filters is designed to estimate the exosystem state based on a composite output observability condition. Then, a distributed adaptive controller is designed. It is shown that the resilient cooperative output regulation problem for the concerned class of uncertain nonlinear MASs can be solved by the proposed control scheme. A simulation example is finally provided to show the effectiveness of the proposed control scheme.

SEISMIC WAVE RECORDER DESIGN FOR DEVELOPMENT FOOTSTEP HUMAN DETECTION ALGORITHMS

The article shoving the results of development seismic signal recorder for purpose of registration human footstep seismic signals. Design of recorder was adopted for collection seismic signals and store it on PC, for next seismic signal processing and creation signal detection and classification algorithms.
 The article provides an overview of the types of seismic waves, their classification is given. The conditions for the propagation of seismic waves are determined, and the features of Rayleigh waves are clarified. The design structure of the seismic sensor has been developed. The specifics of the functioning of the seismic sensor are described, the place and conditions of power supply and placement of the external interface are recognized. The specifics of using the sensor of an electromechanical transducer - geophone and the features of measurements using a stationary earth are described. It is shown that the development of a seismic signal sensor circuit implies the placement of input amplifiers in its structure. The main amplitude-frequency and phase-frequency characteristics of the geophone are presented. Geophone equivalent circuit, amplifier circuit, low-pass filter circuit are presented. Illustrations of types of seismograms are given, recommendations on the features of digital signal processing are given. The order of seismic signal processing is connected with its transmission from the sensor through the amplifying stage, passing through a low-pass filter in order to minimize noise and interference. The next step is to send a signal to the ADC. From the presented graphs of sensitivity and phase shift of the geophone, it follows that special attention should be paid to the curve corresponding to the sensor with an open output. This configuration of the sensor is optimal in the context of the formation of the maximum equal frequency response.
 As papers result was proposed structural and schematic design for all main recorders blocks and software features that required for properly using recorder. Tests in real conditions on test sites have shown the correctness of the choice of schemes of technical solutions for the task of registering seismic waves.

A comparative study on the Implementation of Fractional Order Butterworth Lowpass Filter using Differential Voltage Current Conveyor

In this paper, two fractance devices and an active implementation of a differential voltage current conveyor (DVCC) based on a Butterworth lowpass filter in fractional order are presented (FDs). The transfer function for a frac- tional order system is initially established. The conventional fractional order Butterworth equa- tion is then used to compare the transfer func- tion of the created system. This can be equated to obtain the generalised condition under which the created system functions as a Butterworth fil- ter of fractional order. Additionally, using Monte Carlo analysis, the impact of current and voltage faults on DVCC response is investigated. Finally, to validate the theoretical results, a fractional or- der Butterworth filter is simulated in the PSpice environment using 0.5 μm CMOS technology us- ing a suggested R-C network-based fractional or- der capacitor.

Dynamic Power Sharing Assisted Hybrid Controller for PV Fed Isolated dc Microgrid

This article presents a hybrid control strategy to improve the control and power sharing of a hybrid energy storage system (HESS) used in an isolated dc microgrid. While the photovoltaic panel is the primary energy source, the battery and supercapacitor work together to meet the additional power requirements. A modification to the traditional filter method for dividing the average and transient HESS current components is done by replacing the low pass filter (LPF) with a rate limiter to ensure proper power splitting and smoother battery discharge. The rate limiter integrates power balance into the system and allows for the integration of battery discharge rates, eliminating the problems caused by the unintentional selection of the cut-off frequency. In addition, the HESS current outputs are no longer affected by low order LPF phase delay. A simple prediction based current control is proposed for HESS current regulation to precisely track the rate-limited current references and avoid common windup concerns associated with proportional integral (PI) controllers arising from system nonlinearities and uncertainties. The proposed control approach can reduce the peak overshoot below 2% and settling time during disturbances less than 15%. Simulation and experimental investigations are carried out to validate the effectiveness of the proposed method.

Design and analysis of novel DGS-loaded low-pass filter with wide stopband

Abstract This article deals with design and development of a novel 7th order low-pass filter with defected ground structures for S-band applications. The proposed LPF structure was comprised of dumbbell shaped interdigital defected ground structures and open stubs as series inductor and shunt capacitor in the pass band. In addition, an equivalent circuit model was derived and optimized to achieve a 3-dB cut off frequency about 4 GHz with a reflection coefficient of better than −20 dB. Moreover, proposed low-pass filter was manufactured on a Rogers RO4003C substrate with a dielectric constant of 3.38, the dissipation factor of 0.0027. The developed LPF has a very flat pass-band with a transmission coefficient less than −0.5 dB and the measured transmission coefficient better than −18 dB in the passband (DC-3.6 GHz). Meanwhile, the prototype has a 20 dB harmonic suppression level in the frequency range from 5.54 GHz up to 43.5 GHz. Furthermore, the measured peak to peak group delay variation was less than 170 ps in the passband. The proposed filter has a very compact size of 195.3 mm2.

A Control Bandwidth Optimized Active Damping Scheme for LC and LCL Filter-Based Converters

Control bandwidth and damping performance are two key specifications for high-order LC and LCL filter-based converters. The damping of high-order filter-based converters has been extensively studied. However, the control bandwidth issue was ignored. The quantitative relationship between the control gains and bandwidth is still unclear. Moreover, the delay compensator was designed independently without considering the interactions with the main controller. This paper proposes a control bandwidth-optimized active damping control strategy for the LC and LCL filter-based converters to overcome these shortcomings. With the proposed generalized controller, the close loop transfer function of the N <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup> order filter-based converter can be simplified to an N <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup> order low pass filter with an adjustable cutoff frequency. This greatly simplifies the control bandwidth optimization. To alleviate the negative influence of the computational delay on the control bandwidth, a novel delay compensator is proposed. To reach an overall optimized control performance, the particle swarm optimization (PSO) method is used to optimize the controller and delay compensator parameters simultaneously to realize both high control bandwidth and good damping performance. Experimental results verify the effectiveness of the proposed novel controller.

Design and Fabrication of a Device for Reducing Hand Tremor in Parkinson Patients during Eating.

In this paper, the method of designing a noninvasive device for eliminating hand tremors in Parkinson's patients is presented. The designed device measures the tremors of the patient's hand and implements the tremor control accordingly. Since Parkinson's disease reduces patients' abilities to perform daily activities, this device is designed as an electronic spoon. The inertial measurement units are used to measure hand tremors. The signals got from motion sensors are passed through Butterworth's second order low pass filters to attenuate signals amplitude at frequencies higher than the human hand's natural frequency. The signals are sent to a proposed Proportional Integral (PI) fuzzy controller as a set point signal, and appropriate control signals are applied to two actuators installed orthogonal. Besides motion sensors, a microcontroller is installed inside the spoon handle that implements a PI fuzzy controller and provides control signals for two high speed servo motors installed perpendicularly. As such, the spoon can minimize the tremor effect. In this system, no damper or mass is added to the hand, and the patients are not required to wear an orthosis. The contribution of this paper is twofold. First, we use sensor data fusion to increase measurement accuracy. In this paper, we use accelerometer and gyroscope sensors. Second, we proposed a robust PI fuzzy controller to compensate for the uncertainties and reduce the tremor. The test results show that the hand tremor of Parkinson's patients during eating is reduced up to 75% using this method.

On Certain Noise Filtering Techniques in Fixed Point Iteration-based Adaptive Control

In control applications the use of noise-burdened sensor signals cannot be evaded. Also, certain signals can be lost. This problem traditionally is tackled by the use of Kalman filters that provide some “optimal solution” to these problems based on reasonable assumptions that are not always well underpinned in the practice. These are assumptions are made with regard to the system model and the statistical distribution of the noise signals. The Fixed Point Iteration-based adaptive controller is applicable for various strongly nonlinear models. Because feeding back the order of time-derivative of the system’s variable that immediately can be varied by the control signal, its noise sensitivity can be considerable. In this paper the operation of an unscented Kalman filter-based technique is compared with that of a simple moving window with affine signal approximation, and the use of a third order low pass filter in the control of a modified van der Pol oscillator. In this model a quadratic drag term is added to the original model to describe the motion of the system in turbulent fluid environment. According to the numerical simulations it can be stated that the simpler methods can replace the more complicated Kalman filter.

Artificial intelligence-guided, single-lead EKG may be a game-changer for symptom-to-balloon time reduction in ST-elevated myocardial infarction

Abstract Background Over decades, efforts to shave off life-saving minutes from ST-Elevated Myocardial Infarction (STEMI) care centred on reducing door-to-needle and door-to-balloon times. We firmly believe that symptom-to-balloon time should prove a better focus to this end. Challenges come with this goal as it heavily relies on a patient's perception and initiative to seek care, which we deem intelligent and wearable Artificial Intelligence (AI)-driven Single Lead EKG technologies as an attractive solution in modern-day cardiology. Purpose To provide an accurate, accessible, and cost-effective AI-driven Single Lead STEMI detection algorithm that can be embedded into wearable devices and employed in a self-administered fashion. Methods Database: EKG records from Mexico, Colombia, Argentina, and Brazil from April 2014 to December 2019. Dataset: A total of 11,567 12-lead EKG records of 10[s] length with a sampling frequency of 500 Hz, including the following balanced classes: angiographically confirmed and unconfirmed STEMI, branch blocks, non-specific ST-T abnormalities, normal and abnormal (200+ CPT codes, excluding those mentioned above). Cardiologists manually checked the label of each record to ensure precision. Pre-processing: We discard the first and last 250 samples as they may contain a standardisation pulse. The study applied a digital low pass filter of order 5 with a frequency cut-off of 35 Hz. The mean was subtracted from each Lead. Classification: The determined classes were “STEMI” (Including STEMI in different locations of the myocardium – anterior, inferior, and lateral); and “Not-STEMI” (Combination of randomly sample, branch blocks, non-specific ST-T changes, and abnormal records – 25% of each). Training and Testing: A 1-D Convolutional Neural Network was trained and tested with a dataset proportion of 90/10, respectively. A different model was trained and tested for each Lead, using the central 4,500 samples of the records. The last dense layer outputs a probability for each report of being STEMI or Not-STEMI. Lead V2 showed the best overall results. The model was further tested through the same methodology using the best Lead with a subset of the previous data, excluding the unconfirmed STEMI EKG records (Total 7,230 12-lead EKG records for Confirmed Only STEMI dataset). Performance metrics were reported for each experiment and compared. Results Combined STEMI data: Accuracy: 91.2%; Sensitivity: 89.6%; Specificity: 92.9%. Confirmed STEMI Only dataset: Accuracy: 92.4%; Sensitivity: 93.4%; Specificity: 91.4% (Figure 1). Conclusion By assiduously improving the quality of the model's input, we continue to assess our algorithm's performance and reliability for future clinical validation as a potential remote monitoring and early STEMI detection device. Funding Acknowledgement Type of funding sources: None.

Simulation Based Analysis of Low-Voltage-Tunable Biquad Filter Using Operational Transconductance Amplifiers

ABSTRACT A CMOS realisation of a voltage tunable biquad filter using only MOSFET-based operational transconductance amplifier (OTA) and capacitors has been designed using silicon-based CMOS technology. It operates at a low supply voltage of 0.25 V at a 500 MHz frequency. The filter is theoretically analysed and then simulated using commercially available Cadence Virtuoso tools at 0.18 μm CMOS technology parameters. The proposed design is used to implement second-order low pass, highpass, bandpass, and bandreject filters with the same circuit simply by tuning the input voltage. The bandwidth and cut-off frequency also can be changed by changing the capacitor values.

Calculation of Band-Pass Filters with Fixed Frequencies of Infinite Attenuation

Introduction. When calculating band-pass filters (BPF) with infinite attenuation frequencies using the frequency conversion method, the parameters of the prototype – an inverse or quasi-elliptic low-pass filter (LPF) – are recalculated into BPF parameters according to conventional formulas. Using the selected low-pass filter cutoff frequency and the Q-factor of the band-pass filter, one can select at their discretion only one infinite attenuation frequency (attenuation pole). In order to suppress a pair of concrete frequencies in the attenuation band, the synthesis of BPF should initially fix the frequencies of maximum attenuation and the central frequency of the filter. The reverse transition toward the frequency response parameters of a low-frequency prototype is carried out using frequency conversion formulas.Aim. To develop of a method for calculating band-pass filters with fixed attenuation poles.Materials and methods. Odd-order filters with an additional capacitor in the transverse branch of the П-link and an inductance in the longitudinal branch of the Т-link were used as low-frequency prototypes of the BPF with attenuation poles. Approximation of the frequency response of a low-frequency prototype (inverse or quasi-elliptical LPF) was performed by methods based on solving systems of nonlinear equations.Results. A realizable transfer function (TF) of an n-th order LPF with attenuation poles was written as the ratio of the product of binomials and a polynomial of power n with real coefficients. Systems of equations were derived to determine amplitude-frequency response coefficients with a given frequency of maximum attenuation interference for both types of filters. Analytical expressions for the TF of the low frequency prototypes of 3th and 5th orders were recorded through the capacitances of the BPF circuits tuned to the central and suppressed frequencies, thus allowing the desired capacitances to be directly calculated. The BPF inductances were determined by formulas expressing the dependences of the BPF central frequency on the circuits parameters, taking into account the relationships given in the article. An example of calculating a 10th order quasi-elliptic BPF was provided.Conclusion. The proposed method can be used to determine the BPF parameters directly, without an intermediate calculation and subsequent transformation of the LPF prototype parameters. The given analytical expressions for the frequency response of the П- and Т-shaped BPFs of the 6th and 10th orders make it possible to verify the performed calculations and to correct the frequency response using inductances, when replacing the calculated capacitance values with their standard values.

DVCC Based (2 + α) Order Low Pass Bessel Filter Using Optimization Techniques

This paper proposes the design and analysis of (2 + α) order low pass Bessel filter using different optimization techniques. The coefficients of the proposed filter are obtained by minimizing the error between transfer functions of (2 + α) order low pass filter and third-order Bessel approximation using simulated annealing (SA), interior search algorithm (ISA), and nonlinear least square (NLS) optimization techniques. The best optimization technique based on the error in gain, cut-off frequency, roll-off, passband, stopband, and phase is chosen for designing the proposed filter. The stability analysis of the proposed filter has also been done in W-plane. The simulated responses of the best optimized proposed filter are attained using the FOMCON toolbox of MATLAB and SPICE. The circuit realization of 2.5 order low pass Bessel filter is done using two DVCCs (differential voltage current conveyors), one generalized impedance converter (GIC) based inductor, and one fractional capacitor. The proposed filter is implemented for the cut-off frequency of 10 kHz using a wideband fractional capacitor. Monte Carlo and noise analyses are also performed for the proposed filter. The MATLAB and SPICE results are shown in good agreement.

Parameters uncertainty analysis of posture control of a four-wheel-legged robot with series slow active suspension system

This paper focuses on the posture control performance on uneven terrain for a wheel-legged robot (WLR). Firstly, a novel four-wheel-legged robot (FWLR) with series slow active suspension system (SSASS) is proposed. Secondly, the parameters uncertainty of posture control is studied, and an 11 DOF dynamic model and the corresponding system state equation are presented. Thirdly, to suppress the chattering problem and enhance the robustness of traditional sliding mode controller (TSMC), the second order low-pass filter (SOLPF), equivalent speed control, saturation function, terrain estimation model and the actuator model are introduced into the control system, and an improved sliding mode controller (ISMC) is proposed. Finally, both the co-simulation and experiment on uneven terrain are carried out, the results show that even if the system parameters have 30% variation, the robot posture angle can be improved effectively. That is, the proposed robot and ISMC control strategy have good posture control performance with low parameters sensitivity on uneven terrain. Overall, this paper attempts to provide an effective way for the application of WLR on uneven terrain.