Pole-zero Cancellation Research Articles

Model-Free Filter-Based Trajectory Tracking Controller for Two-Wheeled Vehicles Through Pole-Zero Cancellation Technique

Considering the nonlinear dynamics, this paper devises an advanced position trajectory tracking controller with a model-free filter for two-wheeled vehicle (TWV) applications. The proposed technique preserves a simple structure in the form of the proportional–integral (PI) controller involving the model-free filter and nonlinearly structured feedback gains, which make the following contributions: (a) the proposed filter smooths the position and yaw angle measurements according to the first-order convergence rate without any model information; and (b) the PI control with the nonlinearly structured feedback gains robustly stabilizes the position and yaw angle errors along the desired first-order system to accomplish the trajectory tracking mission, which is obtained by the pole-zero cancellation (PZC) in the presence of modeling errors. MATLAB/Simulink was used to emulate the resulting feedback system and validate the effectiveness of the proposed technique.

Data analysis procedures to improve energy resolution in silicon detectors using GET electronics

This study primarily focuses on improving the energy resolution of Double-Sided Silicon Strip Detectors (DSSSD) through optimized data analysis procedures using General Electronics for Time Projection Chambers (GET). We introduce two edge identification algorithms that demonstrate comparable efficacy. These methods are subsequently integrated with various techniques for measuring pulse amplitude, including sample smoothing and pole-zero cancellation. Notably, sample smoothing significantly enhances performances, achieving a resolution of 0.33% with DSSSD α calibration data. Additionally, we describe and apply the trapezoidal filter, examining its impact on resolution improvement and obtaining comparable results. The study also evaluates how internal GET parameters, specifically the sampling frequency and the shaping time of the Sallen-Key (SK) low-pass filter, affect signal resolution. Higher sampling frequencies and lower values of the SK filter were found to increase performance.

LCL-T Module Reduction of Offshore Photovoltaic Power Generation System Based on Current Feedback-routh Approximation Method

The rapid development of offshore photovoltaic power generation has attracted more and more attention. Aiming at the problem of poor output power quality caused by the randomness and intermittentness of offshore photovoltaic power generation, LCL filters and isolation transformers are widely used on the AC side of photovoltaic power generation systems to improve the power quality of Grid-connected. Although this method has a good suppression effect on harmonics and DC components, its higher order will result in a larger amount of calculation, especially in the simulation of large-scale photovoltaic grid-connected systems, the operating speed will be too slow. In order to increase the simulation rate while ensuring the quality of the output power, the high order LCL-T (LCL filter and isolation transformer) module of the photovoltaic power generation system is reduced in order. When the transformer is not saturated, the LCL-T module reduction method based on the weighted current feedback method is adopted, and the purpose of simplification is achieved through the zero-pole cancellation of the transfer function; When the transformer is saturated, the LCL-T module reduction method based on the Routh approximation method is adopted, Use advanced mathematics formulas to reduce the order of high-order system equivalent processing. The PSCAD/EMTDC simulation software verifies the off-grid characteristics and simulation rate of the reduced-order model.

Study of dead time estimation method based on pulse interval distribution

In nuclear radiation detection, some measured radiation counts are lost due to dead time. Estimation of dead time is necessary to restore the counting information in quantitative analysis. This study aims to propose a method for estimating dead time at high counting rate. First of all, a measurement system of pulse interval distribution was used to estimate the true input counting rate of the detection system and implemented in FPGA. Then, a digital pole-zero cancellation technique was introduced in the measurement system to decrease the decay time constant of pulse. This was aimed at mitigating the impact of pile-up on the pulse interval distribution spectrum, especially at high counting rate. The feasibility of this measurement system at high counting rate was verified by the experimental platform of EDXRF. The dead time was calculated using the measured counting rate and the estimated true input counting rate. The accuracy of the dead time relies on the precision of the estimated true count rate. When the counting rate reaches 600 kCPS, the relative error between the theoretical counting rate and the estimated true input counting rate is less than 5%.

Current Sensorless Pole-Zero Cancellation Output Voltage Control for Uninterruptible Power Supply Systems with a Three-Phase Inverter

This article presents a proportional–derivative (PD) type output voltage regulator without the current feedback, taking into account system parameter and load variations. The main advantages are given as follows: First, the first-order output voltage derivative observer is developed without the requirement of system parameter information, which makes it possible to stabilize the system without current sensing. Second, a simple self-tuner implements the feedback-loop adaptation by updating the desired dynamics accordingly. Third, the observer-based active damping injection for the PD-type controller results in the closed-loop system order reduction to 1 by the pole-zero cancellation, including the disturbance observer as a feed-forward term. The prototype uninterruptible power supply system comprised of a 3 kW three-phase inverter, inductors, and capacitors verifies the practical merits of the proposed technique for linear and nonlinear loads.

Current Sensor-Free Output-Feedback Voltage Control for DC/DC Converters via Critical Damping Injection Technique for Converter-Fed Servo System Applications

This study proposes an observer-based multi-loop output-feedback system that regulates the output DC-link voltage of DC/DC converters to the desired value to lower the system model dependence level. There are a few features: (a) the outer loop injecting the nonlinear active damping to ensure the critically damped output voltage response, (b) a model-independent output voltage derivative observer facilitates the inner loop and eliminates the need for complex matrix calculations for tuning the estimation performance, and (c) the use of a pole-zero cancellation acceleration error stabilizer for the inner loop helps maintain the targeted closed-loop performance. The experimental study adopts a 420 W brushless DC motor dynamo system as the load for the prototype 600 W bi-directional converter controlled using the proposed solution.

Observer‐based critically damped feedback systems for nonlinear roll‐to‐roll printing machine applications under decentralized strategy

SummaryThis article exhibits an advanced observer‐based single‐loop feedback system for roll‐to‐roll (R2R) machine tension control applications by treating the nonlinearities, parameter uncertainties, and closed‐loop performance inconsistency as the main challenges. The proposed solution provides the three features as follows: (a) a critically damped web velocity feedback system governed by double integral control with active damping terms and a disturbance observer (DOB) through first‐order pole–zero cancellation (PZC); (b) a model‐free second‐order PZC observer enabling feedback for the tension derivative information; (c) a combination of a proportional–integral (PI) controller, nonlinearly structured PI gains, active damping terms, and a DOB to assign critical damping performance to each tension loop through first‐order PZC. The simulation results numerically validate the feasibility of the proposed solution.

A Comparison of Classical and Reinforcement Learning-based Tuning Techniques for PI controllers

This study compares two tuning techniques for Proportional-Integral (PI) controllers. The first strategy uses the Pole-Zero Cancellation method, a well-established technique in the field of dynamic systems control. The second strategy introduces an innovative approach by using a reinforcement learning-based technique to adaptively tune a PI controller. To compare these tuning methodologies, a Heating, Ventilation and Air Conditioning (HVAC) control system was selected as a case study to guarantee users’ thermal comfort. In both cases, the HVAC process was modelled as a first-order system without time delay. In addition, the performance of the proposed controllers analysed by evaluating temperature set-point tracking and disturbance rejection caused by the occupancy of people in the room. The results demonstrate that classical methods are efficient and quick to implement, while the use of RL also enables optimization of energy consumption and reduction of operating costs.

Observer-Based Pole-Zero Cancellation Trajectory-Tracking Control for Two-Wheeled Vehicles With Performance Recovery Property

Observer-Based Pole-Zero Cancellation Trajectory-Tracking Control for Two-Wheeled Vehicles With Performance Recovery Property

Estimation of a SOPDT process transfer function for PID tuning

The paper deals with the estimation of a Second-Order-Plus-Dead-Time (SOPDT) process transfer function for the tuning of a Proportional-Integral-Derivative (PID) controller. In particular, different methodologies for the estimation of the transfer function parameters based on the open-loop process step response are proposed and compared to an existing one that has been recently presented in the literature. A pole-zero cancellation strategy is then employed to tune the PID controller. Advantages and disadvantages of the different methods are then discussed by considering the obtained results and implementation issues.

Generalized Haalman tuning of PIDA controllers

In this paper we propose a new tuning methodology for Proportional-Integral-Derivative-Acceleration (PIDA) controllers. First, a third-order-plus-dead-time transfer function of the (high-order) process is estimated by evaluating an open-loop step response. Then, the three time constants of the controller are determined by applying a pole-zero cancellation approach and the proportional gain is finally adjusted in order to obtain a desired maximum sensitivity. The controller filters are selected in order to minimize the effects of the measurement noise and to avoid kicks in the control variable. Simulation results show the effectiveness of the methodology in comparison with PID control.

Zero-Pole Cancellation Based Iterative Learning Control Method for Speed Ripple Suppression of Single Rolling Rotor Compressor

Zero-Pole Cancellation Based Iterative Learning Control Method for Speed Ripple Suppression of Single Rolling Rotor Compressor

Design of a 0.5 V Chopper-Stabilized Differential Difference Amplifier for Analog Signal Processing Applications.

This paper presents a low-voltage low-power chopper-stabilized differential difference amplifier (DDA) realized using 40 nm CMOS technology. Operating with a supply voltage of 0.5 V, a three-stage DDA has been employed to achieve an open-loop gain of 89 dB, while consuming just 0.74 μW of power. The proposed DDA incorporates feed-forward frequency compensation and a Type II compensator to achieve pole-zero cancellation and damping factor control. The DDA has a unity-gain bandwidth (UGB) of 170 kHz, a phase margin (PM) of 63.98°, and a common-mode rejection ratio (CMRR) of up to 100 dB. This circuit can effectively drive a 50 pF capacitor in parallel with a 300 kΩ resistor. The use of the chopper stabilization technique effectively mitigates the offset and 1/f noise. The chopping frequency of the chopper modulator is 5 kHz. The input noise is 245 nV/sqrt (Hz) at 1 kHz, and the input-referred offset under Monte Carlo cases is only 0.26 mV. Such a low-voltage chopper-stabilized DDA will be very useful for analog signal processing applications. Compared to the reported chopper DDA counterparts, the proposed DDA is regarded as that with one of the lowest supply voltages. The proposed DDA has demonstrated its effectiveness in tradeoff design when dealing with multiple parameters pertaining to power consumption, noise, and bandwidth.

A new method for reducing the number of resonance frequencies of mechanical systems within a specified frequency range with inverse structural modification and pole-zero cancellation

Resonance frequencies of a mechanical system are the most important parameters that determine the dynamic characteristics of the system. When the frequencies of the harmonic forces under the influence of the system coincide with the resonance (natural) frequencies of the system, a resonance situation occurs and the mechanical system vibrates with high amplitudes. This can cause serious damage to the system by causing effects such as break, fatigue, impact, noise on the bearings, connections and elements in the system. It is possible to eliminate some resonance frequencies of mechanical systems in an examined frequency range using pole-zero cancellation methods by shifting a resonance frequency of the system to an anti-resonance frequency or an anti-resonance frequency to a resonance frequency. Thus, a solution can be obtained for some vibration problems. In this study, a new method using the Sherman-Morrison formula is presented to eliminate some of the resonance frequencies for some FRFs (Frequency Response Functions) of mechanical systems with pole-zero cancellation. In order to eliminate a selected resonance frequency of the system in any FRF determined using the presented method, a mass (kg) and a grounded spring (N/m) modification are made and the required modification values for this are calculated by solving the obtained non-linear equation set numerically. With the proposed method, it is aimed to contribute to the literature by presenting an alternative approach for the solution of vibration problems by cancelling some selected resonance frequencies. The main highlight of the method is there is no need of a matrix inversion for calculating the required modification values. This provides a very fast solution. In addition, the proposed method uses directly the FRFs of the active coordinates (response, excitation and modification) only, which makes the method very useful for practical engineering applications.

Development of Decentralized Speed Controllers for a Differential Drive Wheel Mobile Robot

This research presents a comprehensive mathematical model and a control-oriented model for a differential drive wheel mobile robot (DDWMR). The components and their interconnection within the robot are thoroughly modeled. The proposed mathematical models are used to analyze the characteristics of the robot. The control-oriented model is a simplified one which will be used to design speed controllers. The performance of the proposed system is evaluated through four case studies, focusing on both stand-alone motor systems and the entire DDWMR. The tracking performance is evaluated using metrics such as absolute error integration and root mean square error. Simulation results show that under ideal step command, the pole-zero cancellation PI speed controller achieves the best tracking performance, while PID controllers obtained from Matlab’s Auto-tuning App perform best for standalone motor systems. For motors in a DDWMR, the PID controller with parameters derived from the Ziegler-Nichols tuning rules provides optimal tracking performance. These simulation results show that there is no universal controller that can achieve the best performance in all situations; rather, each controller is suited to specific circumstances. Nonetheless, in all case studies, better motor speed tracking leads to improved trajectory tracking performance for the robot.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited.

A modified polynomial-based approach to obtaining the eigenvalues of a uniform Euler–Bernoulli beam carrying any number of attachments

Free vibration characteristics in uniform beams with several lumped attachments are an important problem in engineering applications that have to deal with mounting different equipment (e.g. motors, oscillators or engines) on a structural beam. In order to solve the lack of a generalized automatic procedure, this investigation presents a simple solving approach based on analytical means applied to a secular frequency equation for obtaining the natural frequencies of an arbitrarily supported single-span, or multi-span Euler–Bernoulli beam carrying any combination of miscellaneous attachments. The approach is obtained by solving a characteristic polynomial equation using a classical method for computing the roots of a polynomial. Interestingly, if the number of elements is greater than one, a pole-zero cancellation is needed, but it does not require manual interventions such as initial values and iteration. The mathematical approach is validated with bibliographic references and evaluated for accuracy and computational effectiveness. A good agreement is observed with relative error values practically negligible mostly ranging between 10−3 and 10−9 in the first five natural frequencies, which confirms the validity of the presented approach in this paper. The MatLab code that has been developed with the solving approach is freely available as a supplementary material to this paper. Additionally, a MatLab graphical user interface has also been developed in this work which allows to obtain the eigenvalues of a simply supported Euler–Bernoulli beam carrying an undetermined number of lumped elements. The graphical user interface is also available for download, along with help facilities to be run in a Windows operating system and detailed instructions to reproduce the case studies presented here. The proposed scheme (and also the MatLab graphical user interface) is very easy to code, and can be slightly modified to accommodate beams with arbitrary supports.

Design and Testing of a Prototype ASIC for the MTPC Readout at CSNS Back-n White Neutron Source

In this paper, a prototype Application Specific Integrated Circuit (ASIC) for the Multi-purpose Time Projection Chambers (MTPC) at Back-n White Neutron Source is presented. The ASIC integrates 16 readout channels and is fabricated in a 0.18 μm CMOS process. Each channel consists of a Charge Sensitive Amplifier (CSA), a Pole-Zero Cancellation (PZC), two bridged-T shapers, a baseline holder, and a fully differential output buffer. It provides selectable charge ranges of 2 pC and 10 pC, programmable peaking times from 110 ns to 1 μs, and an adjustable output common-mode voltage from 0.7 V to 1.25 V. The ASIC has already been tested and all the results meet the requirements. In the case of 100 pF input capacitance, 2 pC charge range, and 1 μs peaking time, it features a maximum Integral Non-Linearity (INL) of 0.48% and an Equivalent Noise Charge (ENC) of 0.749 fC, which makes the Signal-to-Noise Ratio (SNR) at full-scale input over 2600. In particular, a crosstalk rejection ratio of 63 dB is obtained in this prototype ASIC by using the baseline holder circuit in each channel to generate references for single-ended to differential conversion, isolating noise and crosstalk from the reference path.

Active Second-Order Pole-Zero Cancellation Control for Speed Servo Systems With Current Sensor Fault Tolerance

This study presents an advanced output-feedback technique for speed regulation tasks in servo systems, which reduces the system model independence and is independent of the current feedback, leading to fault tolerance. Hence, the output position error drives the model-free order reduction filter for speed, and the acceleration feedback (as a replacement for the current loop) is admissible. Furthermore, the proposed control law includes specially structured active damping terms in the feed-forward loop to actively trigger second-order pole-zero cancellation, forming a simple single-loop proportional-integral derivative-type structure with compensation terms. Finally, a 420-W prototype DC servo system experimentally validates the effectiveness of the proposed technique.

Feedback Loop Adaptation Speed Feedback Systems for PMSMs via Angle Filtering and Acceleration Stabilization Techniques

This article presents an advanced solution to the speed tracking problem of permanent magnet synchronous motors (PMSMs) subject to two practical concerns: uncertain motor parameter values, load variations, and current feedback dependence level. The results present a few contributions for industrial application: (a) a parameter-independent angle filter (providing speed and acceleration estimates) by modifying the structure of the conventional extended state observer, (b) the angle filter-based pole-zero cancellation acceleration stabilizer removing the <inline-formula><tex-math notation="LaTeX">$q$</tex-math></inline-formula>-axis current dependence of the speed loop to secure the current sensor fault tolerance, and (c) the adaptive speed loop in the analytic form to improve the tracking performance by boosting feedback gain during only the transient periods. Using a dynamo testbed adopting a 700-W PMSM as the test motor, this experimental study verifies the effectiveness of the proposed technique under various operating modes.

Decentralized Current Sensorless Speed Synchronization With Feedback-Loop Adaptation for Multiservo System Applications

This study presents a parameter-independent decentralized speed synchronizer for multiservo systems without a current feedback loop, considering the current dynamics. The observer (not requiring system parameter information) exponentially estimates the speed derivative as updating the speed error to be vanished with the closed-loop pole-zero cancellation nature. The resultant estimates render it possible to implement the proposed decentralized synchronizer a the real-time feedback-loop adaptation, using only the nominal system parameter information. Two sets of QUBE-servo2 and myRIO1900 processors constitute the decentralized experimental platform to verify the closed-loop effectiveness.