Performance Comparison Of Controllers Research Articles

Performance Comparison of Various Controllers for DC-DC Synchronous Buck Converter

DC-DC converters are extensively used in the modern telecommunication and consumer electronics. Design of such converters is a challenge for electrical engineers due to the user requirements and the inherent non linear nature. When the required output does not follow the set-point, a controller is to be used with objective of keeping the error as minimum. For a DC-DC converter, the input and load variations are major reasons which alter the proper functioning. The controller for such DC-DC converter is a circuit or an algorithm which changes the Pulse Width Modulation (PWM) waveform by adjusting the ON-OFF timings thereby keeping the output at the desired value. Quick settling time and rise time to the desired output along with high efficiency, required phase margin, loop bandwidth are the main constraints on the controller. Design of such controller is the main purpose of this research paper. Two types of controllers are designed namely PID controller and Fuzzy Logic Controller (FLC). PID controller is tuned using Internal Model Control (IMC) method and Ziegler Nicholas (ZN) method. FLC with optimum number of rules is designed. The above controllers are compared and it is found that FLC gives the minimum settling time of 1.9ms, overshoot percentage of 13.78 and rise time of 0.654ms. The output variations due to line voltage and load changes are also found to be minimum with FLC.

Designing an Energy Storage System Fuzzy PID Controller for Microgrid Islanded Operation

Recently, interest in microgrids, which are composed of distributed generation (DG), distributed storage (DS), and loads, has been growing as a potentially effective clean energy system to mitigate against climate change. The microgrid is operated in the grid-connected mode and the islanded mode according to the conditions of the upstream power grid. The role of the energy storage system (ESS) is especially important to maintain constant the frequency and voltage of an islanded microgrid. For this reason, various approaches for ESS control have been put forth. In this paper, a fuzzy PID controller is proposed to improve the frequency control performance of the ESS. This fuzzy PID controller consists of a fuzzy logic controller and a conventional PI controller, connected in series. The fuzzy logic controller has two input signals, and then the output signal of the fuzzy logic controller is the input signal of the conventional PI controller. For comparison of control performance, gains of each PI controller and fuzzy PID controller are tuned by the particle swam optimization (PSO) algorithm. In the simulation study, the control performance of the fuzzy PID was also tested under various operating conditions using the PSCAD/EMTDC simulation platform.

A state-space approach for the control of multivariable dynamically substructured systems

Dynamic substructuring is an experimental technique which decomposes a complete dynamical system into a number of sub-components. Critical components are physically tested at full-size and the remaining components are simultaneously simulated in real-time. High-quality control is required to synchronize the responses of the physical and numerical components and to compensate for additional dynamics introduced by actuator systems within the physical substructures. This paper presents a new state-space approach for the analysis and synthesis of dynamically substructured systems and the associated synchronizing controller design. A new state-space substructured framework is also developed to support the synthesis of state-space dynamic models, which then leads to design and analysis of state-feedback, H∞, and adaptive controllers. This framework is applied to an experimental single-mode, quasi-motorcycle substructuring problem, for illustration of the concepts and for the comparison of controller performance. Implementation results demonstrated the improved performance resulting from the new approach and also the effectiveness of adaptive control in coping with uncertain and changing parameters within the physical substructures.

PREDICTIVE HOLOGRAPHIC NEURAL NETWORK CONTROL OF 2 DOF MAGNETIC LEVITATION DEVICE

The objective herein is to demonstrate the feasibility of a real-time digital control of a 2 DOF magnetic levitation device for modeling and controls education, with emphasis on predictive holographic neural network control. The plant of interest is a magnetic levitation device that is nonlinear and open-loop unstable. In this application, the reference model of the plant is a neural network that has an embedded nominal linear model in the network weights. The control based on the linear model provides initial stability at the beginning of network training. In using a holographic neural network the control laws are nonlinear and online adaptation of the model is possible to capture unmodeled or time-varying dynamics. Such an environment provides for experimentation, data collection, system identification and novel control strategy implementation. The environment is used to implement predictive holographic neural networks with real-time dynamic weight tuning and controller performance comparison under various trajectories input. The educational features of this environment are being tested in a senior control engineering classroom setting.

A Human Factors Curriculum for Surgical Clerkship Students

Early introduction of a full-day human factors training experience into the surgical clerkship curriculum will teach effective communication skills and strategies to gain professional satisfaction from a career in surgery. In pilot 1, which took place between July 1, 2007, and December 31, 2008, 50 students received training and 50 did not; all received testing at the end of the rotation for comparison of control vs intervention group performance. In pilot 2, a total of 50 students were trained and received testing before and after rotation to examine individual change over time. University of Massachusetts Medical School. A total of 148 third-year medical students in required 12-week surgical clerkship rotations. Full-day training with lecture and small-group exercises, cotaught by surgeons and educators, with focus on empathetic communication, time management, and teamwork skills. Empathetic communication skill, teamwork, and patient safety attitudes and self-reported use of time management strategies. Empathy scores were not higher for trained vs untrained groups in pilot 1 but improved from 2.32 to 3.45 on a 5-point scale (P < .001) in pilot 2. Students also were more likely to ask for the nurse's perspective and to seek agreement on an action plan after team communication training (pilot 1, f = 7.52, P = .007; pilot 2, t = 2.65, P = .01). Results were mixed for work-life balance, with some trained groups scoring significantly lower than untrained groups in pilot 1 and no significant improvement shown in pilot 2. The significant increase in student-patient communication scores suggests that a brief focused presentation followed by simulation of difficult patient encounters can be successful. A video demonstration can improve interdisciplinary teamwork.

Performance comparison of several classical controllers in AGC for multi-area interconnected thermal system

This paper presents automatic generation control (AGC) of interconnected two equal area, three and five unequal-areas thermal systems provided with single reheat turbine and generation rate constraints of 3% per minute in each area. A maiden attempt is made to apply integral plus double derivative (IDD) controller in AGC. Controller gains in the two-area system are optimized using classical approach whereas in the three and five area systems controller gains and governor speed regulation parameters ( R i) are simultaneously optimized by using a more recent and powerful evolutionary computational technique called bacterial foraging (BF) technique. Investigations reveal on comparison that Integral (I), Proportional–Integral (PI), Integral–Derivative (ID), or Proportional–Integral–Derivative (PID) controllers all provide more or less same response where as Integral–Double Derivative (IDD) controller provides much better response. Sensitivity analysis reveals the robustness of the optimized IDD controller gains and R i of the five area system to wide changes in inertia constant ( H), reheat time constant ( T r), reheat coefficient ( K r), system loading condition and size and position of step-load perturbation.

Analysis and performance comparison of PID and fractional PI controllers

This paper compares the frequency domain performance criterion (Jv) of PI, fractional PI, and PID controllers when a step load disturbance is applied at the plant input. Process information is available in form of first-order plus dead-time (FOPDT) model. In addition, the controllers were compared using the H∞–norm of the sensitivity function as a measure of robustness, and some comments on industrial practice are offered in this context.

2A13 Energy Regenerative Active Vibration Control of Cantilever Beam Using Piezoelectric Actuator and Class D Amplifier

Active vibration control usually reduces vibration amplitude and mechanical energy of vibrating structure. In the situation, actuator of active vibration control system must remove energy from vibrating structure. However, the consideration is inconsistent with a common knowledge of active vibration control, active vibration control system needs external power supply to drive actuator. To find an answer to the inconsistency, power flow in an active vibration control system of a SDOF oscillator using a piezoelectric actuator has been investigated by authors analytically. The piezoelectric actuator is used because it has little internal loss and it makes easy to understand essentials of power flow in the active vibration control system. The investigation shows that the actuator is not consuming power from external source but removing and regenerating energy from the SDOF oscillator. Power consumption of the system is caused by energy loss of the amplifier to drive the actuator. The result implies that an energy regenerative active vibration control system can be realized by reducing energy loss of the amplifier. The energy loss can be reduced by using class D amplifier, high efficient amplifier based on switching operation of semiconductor devices, instead of conventional linear amplifier. The validity of energy regenerative active vibration control system using class D amplifier is shown by a numerical simulation. An advantage of proposing method compared to other energy regenerative vibration control methods and semi-active methods is that proposing method can use any controller used in ordinary active vibration control and can achieve the same control performance because difference between ordinary active vibration control methods and proposing method is only type of amplifier. In this paper, the validity and the advantage are confirmed by experimental comparison of power flow and control performance of two active vibration control systems using a conventional linear amplifier and a class D amplifier with the same controller and the same actuator.

Performance comparison of electrorheological valves with two different geometric configurations: Cylinder and plate

This article presents a control performance comparison of electrorheological (ER) fluid-based valves between cylindrical and plate configurations. After identifying Bingham characteristics of chemical starch-based ER fluid, an analytical model of each valve is established. In order to reasonably compare valve performance, design constraint is imposed by the choosing the same electrode gap and length, and each ER valve is manufactured. Valve performances such as pressure drop and response time are then evaluated and compared through analytical model and experiment. In addition, a time-varying pressure tracking controllability of each ER valve is experimentally realized.

Improved robustness and sensor fault tolerance via a generalized internal model-based fault-tolerant controller

In this paper the synthesis of an implicit fault-tolerant control system that is capable of handling multiple sensor faults in addition to modelling uncertainties is presented. The implicit approach allows sensor fault tolerance without the need for accurate information from the fault diagnosis element. Difficulties encountered when solving for a fault-tolerant control problem commonly related to the reliability and accuracy of its fault diagnosis element are thus avoided. Based on extensions to the generalized internal model-based controller (GIMC), the new development proposed in this paper includes the introduction of an Hinfin loop-shaping controller in the structure to facilitate best control performance augmented by standard H∞ controllers as a fault-compensating block to facilitate fault tolerance towards multiple sensor fault conditions and robustness towards modelling uncertainties. Crucial stability and robustness analysis/proofs of the proposed design are conveniently obtained. Sensor faults are modelled as functions within a bounded family of signals and an internal model of this family is embedded into the fault compensating H∞ controller which is cascaded to the H∞ loop-shaping controller. The reliability of operation towards modelling uncertainties is also shown to be guaranteed. Its potential for providing multiple sensor fault tolerance in addition to robustness towards modelling uncertainties is illustrated with a flight control system example; results are significant, as observed in a comparison of control performance with standard H∞ and μ controllers.

A performance comparison of robust adaptive controllers: linear systems

We consider robust adaptive control designs for relative degree one, minimum phase linear systems of known high frequency gain. The designs are based on the dead-zone and projection modifications, and we compare their performance w.r.t. a worst case transient cost functional with a penalty on the $$\mathcal{L}$$ ∞ norm of the output, control and control derivative. We establish two qualitative results. If a bound on the $$\mathcal{L}$$ ∞ norm of the disturbance is known and the known a priori bound on the uncertainty level is sufficiently conservative, then it is shown that a dead-zone controller outperforms a projection controller. The complementary result shows that the projection controller is superior to the dead-zone controller when the a priori information on the disturbance level is sufficiently conservative.

ADAPTIVE CONTROL OF CHAOTIC n-SCROLL CHUA'S CIRCUIT

In this paper, stabilization of fixed points of n-scroll Chua's circuit is investigated. Two adaptive control methods are proposed. One is based on an unstable low pass filter; the other is based on a stable and an unstable low pass filter. The simulation results verify the effectiveness of the two proposed control methods and performance comparisons show that the second control method is superior to the first one with regard to control speed and attraction basins.

Comparison of vibration control performance between flow and squeeze mode ER mounts: Experimental work

This paper proposes two different electrorheological (ER) mounts and compares vibration control performance. Dynamic models of flow and squeeze mode mounts are formulated and design parameters are determined by considering a static load of 200 kg. After manufacturing two ER mounts, the field-dependent displacement transmissibilities are evaluated in frequency domain. A simple sky-hook controller is then designed to attenuate the imposed vibration and the controller is experimentally realized. Vibration control responses are evaluated in frequency domain and compared between the flow and squeeze mode ER mounts.

Performance comparison of controllers acting on a batch pulp digester using Monte Carlo modelling

Finding a suitable control structure for any process usually involves comparing the performance of different possible control structures and choosing one which best satisfies chosen criteria. It is desirable to do this performance comparison off-line, as installation of a sub-optimal controller will cost both time and money. Monte Carlo modelling provides a well documented method of evaluating the statistical properties of stochastic systems. Applied to control system design, Monte Carlo modelling can incorporate detailed process models and accurate estimates of input distributions to give an accurate estimate of the effect of different control strategies on the system. In this study, Monte Carlo modelling was used to compare three candidate controllers in order to determine the best controller in terms of two criteria, namely variance reduction and setpoint tracking. The modelling technique yielded results that could be interpreted without difficulty, showing one controller to be clearly superior to the others according to these criteria. These results can be used to implement the best controller without expensive trial and error procedures. In situ experiments on an operational digester correlated well with the simulation results, showing the best controller to reduce variance by 43% and reduce the mean error by 90% when compared to the controller currently in use. It is shown that Monte Carlo modelling is a viable technique for controller performance analysis on highly nonlinear processes, due to the increasing availability of powerful computing systems.

Distributed Control Design for Parabolic Evolution Equations: Application to Compressor Stall Control

We present a theoretical study of distributed control design for semilinear parabolic nonlocal evolution equations with an application to axial compressor stall control using air injection. By taking advantage of the spatial invariance of the equations, a linear controller is constructed (following Bamieh et al.) via linear quadratic control of each Fourier mode. We derive sufficient conditions for the linear controller to stabilize the full nonlinear system. Concepts such as controller decentralization, finite-dimensional implementation, inverse-optimality, and beneficial nonlinearities are discussed. In the second part of this paper, these developments are applied to a model of axial compressor control with air injection. The unactuated model is derived following the work of Moore and Greitzer and the model coupled with air injection actuation follows the works of Behnken et al. and Weigl et al. A numerical study of the control designs is pursued and the comparison of controller performance is discussed. The techniques presented here are expected to be useful for distributed control design of a much broader class of nonlinear reaction-diffusion systems.

Optimal Utilization, Sizing, and Steady-State Performance Comparison of Multiconverter VSC-Based FACTS Controllers

This paper describes a method for optimal dimensioning of multiconverter voltage sourced converter-based FACTS controllers. This general method allows comparisons of the steady-state performance and effectiveness of all single-, two-, and three-converter controllers in achieving specific power system operating objectives. The controllers considered include the generalized unified power flow controller and its subdevices, i.e., the static compensator, the static synchronous series compensator, the unified power flow controller, and the interline power flow controller. The effects of various shunt and series converter size modularizations in multiconverter FACTS controllers are demonstrated. Sensitivities to power system topology related issues such as system strength, parallel paths, and compensated line impedances, as well as system loading, have been analyzed. An optimal power flow (OPF)-type formulation with embedded effective impedances and/or current injections is utilized to provide a single framework for representing all single- and multiconverter FACTS controllers considered. A small power system model is utilized in this study mainly focusing on the FACTS controller utilization and performance. Realistic constraints representing various converter limits have been implemented. MATLAB optimization routines are utilized.

Magnetic Levitation Hardware-in-the-Loop and MATLAB-Based Experiments for Reinforcement of Neural Network Control Concepts

This paper discusses the use of a real-time digital control environment with a hardware-in-the-loop (HIL) magnetic levitation (Maglev) device for modeling and controls education, with emphasis on neural network (NN) feedforward control. Many educational advantages are realized for the students if a single environment is used for simulation, hardware implementation, and verification as compared with multienvironment settings. This real-time environment requires two personal computers (host and target) employed to control an HIL system. It requires software tools by MathWorks, Inc., a C++ compiler, an off-the-shelf data acquisition card, and the HIL (a nonlinear, open-loop, unstable, and time-varying, custom-built Maglev device) to be controlled. This environment provides for experimentation, such as data collection for system identification using NNs and their implementation as static nonlinear feedforward controllers. In addition, this environment was used to implement and demonstrate NNs with real-time dynamic weight tuning and controller performance comparison under various inputs or changes in the HIL device dynamics, as shown in the presented examples. The educational features of this environment were verified in a classroom setting in a graduate-level NN class. The presented environment is applicable to senior or graduate level (introductory intelligent and digital control) or a general introductory course on NNs with applications.

Control aspects of a robotic haptic interface for kinesthetic knee joint simulation

A new 6 DOF (degrees of freedom) haptic device is presented for display of the dynamic properties of a virtual human knee in orthopaedic training. In order to achieve the high impedance requirements in this application an industrial robot has been selected and extended with a PC-based high performance controller hardware and redundant safety features. Two control architectures—a force-command and motion-command control—are presented and both implemented in a 1 DOF application. With a new method for evaluation and comparison of controller performance in terms of impedance error the experimental results reveal that motion-command provides better accuracy for display of the high impedances specific to the human knee application.

A guide to using performance measurement systems for continuous improvement.

The Joint Commission on Accreditation of Healthcare Organizations requires accredited organizations to use a performance measurement system that meets its inclusion requirements to satisfy performance outcome and measurement expectations. The system, known as the ORYX initiative, is used for both internal performance control and external performance comparisons. This article outlines a three-step approach to using a performance measurement system based on the philosophy of continuous improvement and the methods of statistical process control (SPC). SPC, the methodology recommended by the Joint Commission, can be applied to the analysis of many quality measures and can be implemented with Microsoft Excel software.

045 Comparison of control performance in artificial respiration by different adaptive methods using programmable respirator

045 Comparison of control performance in artificial respiration by different adaptive methods using programmable respirator