Compensator Design Research Articles

Research on frequency reconfigurable bowtie antenna loaded with triangular shaped fractal parasitic elements

ABSTRACT The bowtie antenna loaded with triangular-shaped fractal parasitic elements (TSFPE) is a kind of novel dual-band antenna with excellent performance and unique advantages. If it can achieve frequency reconfiguration by loading RF switches, its application will be further expanded. This paper attempts to load the RF switch onto the novel antenna. It is found in the research that the TSFPE performance is seriously deteriorated after loading the RF switch due to the discontinuous effect of RF switch loading. Therefore, a trapezoidal patch compensation loading scheme is proposed to ensure the performance of TSFPE. Through trapezoidal patch loading, S11 of TSFPE can be effectively improved, and its gain can be increased by 1.6 dB. The simulation and measurement results show that the designed frequency reconfigurable antenna has good performance in X/Ku/ka bands. The idea and method of compensation design after switch loading can be further popularized and applied.

A convex optimization approach to multi-objective design of two-stage compensators for MIMO linear systems

The previous design of two-stage compensators with multi-objectives concerns the closed-loop stability, the low-sensitivity, and the satisfactory time-domain performance. However, the design only considers the single-input single-output system. This paper aims to present the design of two-stage compensators for multi-input multi-output (MIMO) linear systems which contain dynamical interaction between inputs and outputs. When Youla parameterization is applied to the MIMO linear system, the design criteria can be cast as a nonlinear optimization. In addition, the infinite dimension optimization problem is approximated to a finite dimension problem with Ritz approximation. The suitable form of design parameters is proposed to ensure the low sensitivity of the MIMO system. The two-stage compensator design is formulated as convex optimization which is efficiently solved using available solvers. Finally, the two-stage compensators are designed for Wood and Berry’s model of binary distillation column. The numerical results indicate that all design objectives of frequency domain and time domain can be achieved by the two-stage compensators.

Co-simulation-based digital twin for thermal characteristics of motorized spindle

To improve the accuracy of thermal characteristics analysis of motorized spindle, an online correction model of thermal boundary conditions is proposed based on BP neural network (BPNN), the experimental data and simulation results are used to construct the BPNN model to correct the thermal boundary conditions of motorized spindle. Based on the co-simulation of Ansys, Matlab, and LabVIEW, a digital twin system for thermal characteristics is built to precisely predict the temperature field and thermal deformation of a motorized spindle under varied operating conditions. The experimental results show that the prediction accuracy of temperature field is greater than 98%, and the prediction accuracy of thermal deformation is greater than 96%, which effectively improves the simulation accuracy and robustness of thermal characteristics, and provides the foundation for the error compensation and thermal optimization design.

Series PIDA Controller Design for IPDT Processes

This paper discusses optimal design of the series proportional–integral–derivative–accelerative (PIDA) controller for integral-plus-dead-time (IPDT) plants. The article starts with the design of disturbance reconstruction and compensation based on proportional-derivative-accelerative (PDA) stabilizing controllers. It shows that by introducing positive feedback by a low-pass filter from the (limited) output of the stabilizing PDA controller, one gets disturbance observer (DOB) for the reconstruction and compensation of input disturbances. Thereby, the DOB functionality is based on evaluating steady-state controller output. This DOB interpretation is in full agreement with the results of the analysis of the optimal setting of the stabilizing PDA controller and of its expanded PIDA version with positive feedback from the controller output. By using the multiple real dominant pole (MRDP) method, it confirms that the low-pass filter time constant in positive feedback must be much longer than the dominant time constant of the stabilized loop. This paper also shows that the constrained PIDA controller with the MRDP setting leads to transient responses with input and output overshoots. Experimentally, such a constrained series PIDA controller can be shown as equivalent to a constrained MRDP tuned parallel PIDA controller in anti-windup connection using conditional integration. Next, the article explores the possibility of removing overshoots of the output and input of the process achieved for MRDP tuning by interchanging the parameters of the controller transfer function, which was proven as very effective in the case of the series PID controller. It shows that such a modification of the controller can only be implemented approximately, when the factorization of the controller numerator, which gives complex conjugate zeros, will be replaced by a double real zero. Neglecting the imaginary part and specifying the feedback time constant with a smaller approximative time constant results in the removal of overshoots, but the resulting dynamics will not be faster than for the previously mentioned solutions. A significant improvement in the closed-loop performance can finally be achieved by the optimal setting of the constrained series PIDA controller calculated using the performance portrait method. This article also points out the terminologically incorrect designation of the proposed structure as series PIDA controller, because it does not contain any explicit integral action. Instead, it proposes a more thorough revision of the interpretation of controllers based on automatic reset from the controller output, which do not contain any integrator, but at the same time represent the core of the most used industrial automation. In the end, constrained structures using automatic reset of the stabilizing controller output can ensure a higher performance of transient responses than the usually preferred solutions based on parallel controllers with integral action that, in order to respect the control signal limitation, must be supplemented with anti-windup circuitry. The excellent properties of the constrained series PIDA controller are demonstrated by an example of controlling a thermal process and proven by the circle criterion of absolute stability.

Novel Design Method in Wireless Charger for SS Topology with Current/Voltage Self-Limitation Function

This study proposes a novel wireless power transfer (WPT) resonance compensation design method based on the SS topology with a self-limitation function that achieves fault tolerance without additional components when the secondary circuit is in a short and open state. Conventionally, WPT compensation topologies have constant current (CC) or constant voltage (CV) output characteristics. The CC and CV characteristics can lead to overvoltage and overcurrent, respectively. Several control systems have been proposed to counter this issue; however, they tend to increase the cost and weight of the system. The proposed topology has a self-limitation function that limits the voltage–ampere output. Here, the wireless charging system was designed after the parameters were obtained using the proposed analysis. The performance of the proposed design was verified by configuring a 400 W experimental prototype and comparing it with the conventional series–series (SS) topology. Experimental results indicated that the system could effectively limit the output voltage and current resulting from open-or short-circuit states.

Two-mirror aerial mapping camera design with a tilted-aplanatic secondary mirror for image motion compensation.

The optical compensation method is a promising method to compensate the image motion by driving the optical element of the system. However, the tilt motion of the optical element could induce the degradation of the image quality. Based on the Nodal Aberration Theory (NAT), this paper proposes a novel optical image motion compensation design with a secondary tilt-aplanatic two-mirror optical system (STATOS), which achieves the insensitivity on the image quality of the optical system. First, the properties of coma-free pivot point depending on the location of stop at primary mirror or secondary mirror have been analyzed respectively. Then the calculating method about construction parameters in terms of STATOS is developed. Further, the maximum tilt angle of secondary mirror could be solved using NAT under ordered specific restriction. Finally, a prototype is designed with SM-tilting result of MTF value maintain above 0.32 at the cut-off frequency of detector, where the principal distance could remain stable and the changed distortion is better than 0.03%. A test flight has been carried out to prove the desired results and feasibility of STATOS used in an aerial mapping camera.

Automatic phase error compensation of rotary traveling wave oscillator: Analysis and design

Automatic phase error compensation of rotary traveling wave oscillator: Analysis and design

An anti-windup control strategy for discrete time-delay system based on triple Lyapunov functional

This paper addresses the design of a dynamic output feedback-based anti-windup compensator to mitigate the windup phenomenon for a discrete time-varying delayed system with input saturation to establish the asymptotic stability. Linear matrix inequalities–based stability conditions are derived locally and globally. The controller for the closed-loop system is designed to reduce the effect of external bounded disturbances by utilizing the linear matrix inequality approach. The novel triple Lyapunov–Krasovskii functional along with reciprocal convex inequality is used to solve the expressions contained in the forward difference of the functional and to maximize the basin of attraction. Finally, industrial examples are simulated to prove the effectiveness of the proposed criterion.

The optimal design of repetitive controllers based on inverse frequency response

AbstractThis article presents a complete design of non‐causal finite impulse response (FIR) and infinite impulse response (IIR) compensators for repetitive control. The concept of repetitive controllers involves imitating the inverse frequency response of the feedback control system by minimizing the amplitude of error propagation from one period to the next in the frequency domain. The FIR compensator design has already been presented in our previous work. However, it was not complete since some parameters, such as the number of causal gains and total number of gains were still left open for the designers to select. This work provides a reasonable suggestion on how to choose parameters based on the steepest descent method. In addition, an IIR compensator is further developed based on the designed FIR design. The gains of the IIR compensator are adjusted by aiming to minimize the cost function using the steepest descent. As can be observed from the results, the IIR compensator developed from the FIR compensator cannot overcome the original FIR compensator since its learning performance is relatively slow and the extra gains added to the denominator increase memory usage when executing.

Compensation regulation in banking: Executive director behavior and bank performance after the EU bonus cap

The regulation that caps executives’ variable compensation, as part of the Capital Requirements Directive IV of 2013, likely affected executive turnover, compensation design, and risk-taking in EU banking. The current study identifies significantly higher average turnover rates but also finds that they are driven by CEOs at poorly performing banks. Banks indemnified their executives by off-setting the bonus cap with higher fixed compensation. Although our evidence is only suggestive, we do not find any reduction in risk-taking at the bank level, one purported aim of the regulation.

An intelligent estimation-based large-scale envelope control for variable cycle engine with packet dropout

The distributed control system is designed to match the advanced variable cycle engine (VCE) with significant advantages, such as the reduced weight and the low cost by introducing the network. In addition to these advantages, the packet dropout follows and may destroy the performances of the controlled systems. Therefore, except for the engine's strong nonlinearity and uncertainty, the effective control design should also possess the ability to handle the packet dropout. The contribution of this study is not only improving the control quality by creatively designing a large-scale intelligent dynamic estimator but also reinforcing the robustness and extending the application of engine control. A novel intelligent estimation-based large-scale envelope (IEBLE) control design for the VCE with packet dropout is proposed. The new framework consists of two parts: high-accuracy estimation and robust control. The intelligent dynamic estimator is developed by deep learning architecture to compensate for the missing information and supply the essential inputs for the control. With the estimated inputs, a model-based large-scale envelope control design is proposed. This separation between information compensation and control design distinguishes our approach from the centralized control of packet dropout. We formulate the engine's nonlinear dynamic in the full envelope as an optimal Takagi-Sugeno system. The engine dynamic and steady parameters are extracted as features. By the intelligent clustering of the features, the rule number and consequent models of each rule are optimized, which renders the resulting optimal system with the high accuracy of the engine's dynamic and steady performances as well as the minimum rules. Finally, the control gain is scheduled based on the fuzzy inference of the optimized system. Afterwards, this design is applied to a VCE as a demonstration. The comparisons between the proposed control and the H∞ and LQR controllers are conducted in different scenarios to evaluate the control quality and robustness. The experimental results show the superior performances, the effectiveness and robustness of the new control, regardless of the packet dropout, large-scale nonlinearity and uncertainty.

Design of a Robotic Spherical Wrist with Variable Stiffness

This paper discusses the design of an adjustable force compensator for a spherical wrist dedicated to robot milling and incremental sheet metal forming applications. The design of the compensator is modular and can be introduced to any existing manipulator design as a single multi-body auxiliary system connected with simple mechanical transmission mechanisms to the actuators. The paper considers the design of the compensator as an arrangement of elastic springs mounted on moving pivots. The moving pivots are responsible for adjusting the stiffness of the wrist-compensator coupling. Special attention is given to two compensation schemes in which the value of the external force can be known or unknown, respectively. The simulation results show that the analytical derivation of the compensator leads the main actuators to spend zero effort to support the external force.

Compensator Design Via the Separation Principle for a Class of Semilinear Evolution Equations

Compensator Design Via the Separation Principle for a Class of Semilinear Evolution Equations

Design, implementation and performance evaluation of different digital control techniques for current controlled DC-DC Buck converter

The paper presents modelling, control architecture, analysis and design of digital compensators for single feedback-loop voltage mode control as well as two feedback-loop average current mode control and peak current mode control of current controlled DC-DC Buck converter operating in continuous conduction mode with output current as control variable. The compensators are derived using digital redesign approach, simulated on MATLAB, implemented as control algorithms on Texas Instruments' 32-bit TMS320F28069M microcontroller platform, and experimentally validated by testing with a laboratory prototype of current controlled Buck converter. Simulation and experimental results are discussed, compared and evaluated for converter output current performance in tracking reference current signal as well as in regulation against input voltage and load disturbances. Salient features of each control technique are identified and described to determine its suitability in applications of DC-DC converters requiring controlled output current.

Design of gravity compensation and machining process for robotic belt grinding (invited)

Design of gravity compensation and machining process for robotic belt grinding (invited)

データ駆動型フィードバック変調器による非線形補償器の設計

Nonlienar compensator design is an important issue that affects performance of control systems as a whole. Despite its importance, the actual nonlinearity we encounter differs from case to case. Thus systematic design and adjustment of nonlinear compensator is still not easy, and often depend on individual know-hows.

Evaluation of SVC-Coupled Hybrid DSTATCOM using JLMS Algorithm for Enhancement of Power Quality

Abstract This research study explains the design and performance of a Static VAR Compensator (SVC) coupled Hybrid Distribution Static Compensator (DSTATCOM) for low voltage power distribution system (PDS). A comparative analysisis done between Voltage Source Inverter (VSI)-based DSTATCOM and SVC Hybrid DSTATCOM using Jordan Least Mean Square (JLMS) algorithm to alleviate the shunt-related power quality (PQ) glitches. The specific design is obtained as compared to the existing neural network toolbox algorithm to improve the estimation speed and accuracy. The main objective is to extract the tuned weighted values of fundamental active and reactive power components of distorted load currents for the switching signal generation using an adaptive JLMS algorithm.Several functions of DSTATCOM and hybrid DSTATCOM using this JLMS controller are showcased for harmonics curtailment, power factor (p.f.) improvement, load balancing, voltage regulation, etc. Simulation results on an SVC Hybrid DSTATCOM have shown an acceptable level of performance under unbalanced loading situations. Finally, some comparative results are provided to validate the feasibility and effectiveness of the suggested topology.

Design and Synthesis of the Gravity Compensator with a Non-zero Length Spring

Design and Synthesis of the Gravity Compensator with a Non-zero Length Spring

Stimulating achievements: The mediating effect of employee commitment between high-performance work practices and employee engagement

Drawing on the social exchange paradigm, this study evaluated the mediating effects of employee commitment (EC) in the relationship between high-performance work practices (HPWP) and employee engagement (EE) in Nigeria. The study used the social exchange theory and this paradigm has been previously used in the works of Blau (1964), Gouldner (1960), and Settoon et al. (1996). The study adopts a cross-sectional survey research design via questionnaire administration. Three employee engagement (vigor, dedication and absorption) and employee commitment (affective, normative and continuance) dimensions, and six high-performance work practices (employee selection process, motivational compensation, job and work design, participative decision-making, information sharing, and training/development) were employed. Data collected from one hundred and sixty-eight employees in selected ministries in Delta State were analyzed via structural equation modeling (SEM). Results showed that engagement positively affects high-performance work practices. The result also indicated that employee commitment mediated the influence of high-performance work practices on employee engagement. The results further suggest that affective commitment does not mediate the link between vigor and high-performance work practices. Notably, the theoretical and managerial inferences have been methodically discussed in this paper.

Stability Analysis and Control Design for Multiterminal HVDC Network With Power Flow Controller

The power flow control in high-voltage direct current (HVDC) grids can be improved by employing the interline dc power flow controller (IDCPFC). This article presents an improved control scheme using IDCPFC to balance power flow in the dc networks. In this work, a differential-mode transformer (DMT) is used in combination with a bidirectional buck converter to form a variable DMT. In comparison to the existing methods, the proposed system is scalable to higher voltages and powers, which makes it suitable for high-voltage dc transmission systems. Analysis of a small-signal model of the proposed method and design of compensator for improvement of transient behavior is performed. A simulation is performed with independent feed-forward and feedback control to show the effectiveness of the proposed method. The proposed method is also validated through a 600-W experimental prototype. The experimental results show that the current flow between lines is controlled for unbalance load conditions.