Control Performance Evaluation Research Articles

Dynamic characteristics and control capability of a piezostack actuator at high temperatures: experimental investigation

In this study, experiments are conducted to evaluate dynamic characteristics and position tracking control performance of a piezoelectric actuator at various temperature conditions including up to 180 °C. An experimental apparatus consisting of a heat chamber, piezostack actuator, a laser sensor, a gap sensor, a temperature sensor, a data acquisition board, a function generator and a computer is established. To obtain the dynamic characteristics of a commercial piezostack actuator, desired input signals, which are sinusoidal waveforms with several different frequencies, are generated by the function generator, and actual controlled output signals are detected by the laser sensor. In this experiment, the heat chamber regulates temperature conditions of the piezostack actuator for a sufficient time before starting next test. After discussing the temperature dependent dynamic properties such as blocking force, another experimental setup is established to evaluate control performance of the piezostack actuator at high temperatures. A proportional-integral-derivative feedback controller which does not require an exact dynamic model of the system is designed and experimentally realized using a microprocessor for the position tracking control. Control performances such as position tracking error are measured at various temperatures and presented in time domain.

Threshold Optimization and Performance Evaluation of a Classical Knock Controller

Threshold Optimization and Performance Evaluation of a Classical Knock Controller

Second-order sliding-mode control for a pressurized water nuclear reactor considering the xenon concentration feedback

This paper presents findings on the second-order sliding-mode controller for a nuclear research reactor. Sliding-mode controllers for nuclear reactors have been used for some time, but higher-order sliding-mode controllers have the added advantage of reduced chattering. The nonlinear model of Pakistan Research Reactor-1 has been used for higher-order sliding-mode controller design and performance evaluation. The reactor core is simulated based on point kinetics equations and one delayed neutron groups. The model assumes feedback from lumped fuel and coolant temperatures. The effect of xenon concentration is also considered. The employed method is easy to implement in practical applications, and the second-order sliding-mode control exhibits the desired dynamic properties during the entire output-tracking process. Simulation results are presented to demonstrate the effectiveness of the proposed controller in terms of performance, robustness, and stability.

Voltage stability enhancement using thermostatically controlled appliances as a comfort-constrained virtual generator

Conventional direct load‐shedding for achieving static voltage stability lacks considerations on both customer comfort and energy efficiency, resulting in higher cost and emission. A novel security‐based, optimal load‐shedding strategy considering customer comfort settings is presented in this paper. A temperature priority list method is used to model the virtual generator (VG) consisting of thermostatically controlled appliances (TCAs). To illustrate the control process and performance evaluation of the proposed load‐shedding scheme, a modified IEEE 6‐bus test system is used. Three heat, ventilation, and air‐conditioning (HVAC) groups are numerically simulated to respond to optimal load shedding signals. Reduced responsive load population, variations of temperature dead‐bands, and different outdoor temperature profiles are modeled to evaluate the capacity variations of the VG and its control performance. The results demonstrate that TCAs can provide satisfactory voltage stability.

Step Response Identification of a Quadcopter UAV Using Frequency-sampling Filters

This paper presents an approach to identify a quadcopter's closed-loop step response for evaluation of control performance. The first step in the proposed approach is data acquisition using a relay feedback experiment and the second step is step response estimation using frequency sampling filters. The proposed approach provides engineers with an intuitive way to more preciously evaluate the designed controllers and to obtain better controller tuning parameters. To validate this approach, experiments are conducted on a quadcopter test-bed and comparisons are made between the estimated step response and the step response from testing.

Design and performance evaluation of Fractional ORDER controller for Brushless DC Motor

Recent developments and advancements in the areas of permanent magnets, power electronics and modern control technologies have significantly influenced the wide-spread use of Brushless DC (BLDC) motor drives. BLDC motors are now, widely used in many applications such as servo drives, computer peripheral equipments and electric vehicles due to their high power density, high efficiency, compact size and easier control. In this paper a control scheme is presented which uses the traditional PID controller for the speed control of BLDC motor. PID controller is designed both by Zeigler-Nichols tuning method and Genetic Algorithm. A controller based on fractional order PID is also designed using Genetic algorithm and the performances of fractional PID controller are compared with the performance of PID controller. MATLAB/SIMULINK software is used to simulate and test the performances of the designed controllers.

Higher order sliding mode controller design for a research nuclear reactor considering the effect of xenon concentration during load following operation

Reactor power control is one of the most important problems in a nuclear power plant. This paper presents the higher order sliding mode controller (H.O.S.M.C.) which is a robust nonlinear controller for a nuclear research reactor considering the effect of xenon concentration during load following operation. Sliding mode controllers for nuclear reactors were developed before. Traditional sliding mode technique has intrinsic problem of chattering. To cope with this problem higher order sliding mode (HOSM) is used. The nonlinear model of a research reactor (Pakistan Research Reactor-1) has been used for higher order sliding mode controller design and performance evaluation. The reactor core is simulated based on the point kinetics equations and three delayed neutron groups. The model assumes feedback from lumped fuel and coolant temperatures. The effect of xenon concentration is also included. The employed method is easy to implement in practical applications and moreover, the higher order sliding mode control exhibits the desired dynamic behavior during the entire output-tracking process. Simulation results show the effectiveness of the proposed controller in terms of performance, stability and robustness against disturbances.

English

This paper describes a design procedure for a Grey ANFIS based power system stabilizer (GrANFISPSS) and investigates their robustness for a multi-machine power system. Speed deviation of a machine and its derivative are chosen as the input signals to the GrANFIS-PSS. A four-machine and a two-area power system is used as the case study. Computer simulations for the test system subjected to transient disturbances i.e. a three phase fault, were carried out and the results showed that the proposed controller is able to prove its effectiveness and improve the system damping when compared to a conventional lead-lag based power system stabilizer controller. The simulation result shows that the GrANFIS-PSS can be designed to achieve good performance merely using the combination of Grey prediction and Adaptive Neuro-Fuzzy Inference System (ANFIS). GrANFIS-PSS is designed to damp out the low frequency local and inter-area oscillations of the Multi-machine power system. By applying this GrANFIS-PSS to the power system the damping of inter-area modes of oscillations in a multi-machine power system is handled properly. The effectiveness of the proposed GrANFIS-PSS is demonstrated on two area four machine power system (Kundur system), which has provided a comprehensive evaluation of the learning control performance. Finally, several fault and load disturbance simulation results are presented to stress the effectiveness of the proposed GrANFIS-PSS in a multimachine power system and show that the proposed intelligent controls improve the dynamic performance of the GrANFIS-PSS and the associated power network

초고층 건축물의 수직 구획화에 따른 급기가압제연시스템 성능평가에 관한 연구

초고층 건축물의 수직 구획화에 따른 급기가압제연시스템 성능평가에 관한 연구

Pyramidal reaction wheel arrangement optimization of satellite attitude control subsystem for minimizing power consumption

The pyramidal reaction wheel arrangement is one of the configurations that can be used in attitude control simulators for evaluation of attitude control performance in satellites. In this arrangement, the wheels are oriented in a pyramidal configuration with a tilt angle. In this paper, a study of pyramidal reaction wheel arrangement is carried out in order to find the optimum tilt angle that minimizes total power consumption of the system. The attitude control system is analyzed and the pyramidal configuration is implemented in numerical simulation. Optimization is carried out by using an iterative process and the optimum tilt angle that provides minimum system power consumption is obtained. Simulation results show that the system requires the least power by using optimum tilt angle in reaction wheels arrangement.

Analysis and modelling of glucose metabolism in diabetic Göttingen minipigs

This paper introduces an improved physiological animal model with diabetic Göttingen minipigs, which focuses on the application of human therapy devices and metabolic system analysis. Based on measurement data-sets collected by metabolic test procedures, a new mathematical minipig model is developed. The model consists of 16 differential equations and describes the diabetic porcine glucose metabolism according to the human model published by Sorensen. In the future, the mathematical model will be used as a basis for controller design and the physiological model for experimental control performance evaluation.

A new active control performance index for vibration control of three-dimensional structures

Remarkable results have been reported about conventional active control algorithms during the last 30years, but nearly all the existing literature considers 2-dimensional in plane structures to implement and verify the active control algorithms. To simulate the behavior of real buildings more accurately, more realistic and complex models should be used in the performance evaluation and design of controllers and their control algorithms. This paper presents a new performance index for active vibration control of three-dimensional structures. To analytically validate the proposed performance index, a six story three-dimensional structure is considered as an example with a fully active tendon controller system implemented in one direction of the building. Tier building formulation is used for three-dimensional dynamic analysis. The building is modeled as a structure composed of members connected by a rigid floor diaphragm such that it has three degrees of freedom at each floor, i.e., lateral displacements in two perpendicular directions and a rotation with respect to a vertical axis for the third dimension. The performance of the building with the active tendons controlled using a classical linear optimal control algorithm is compared to the performance of the proposed control algorithm under several far-fault and near-fault earthquakes using several performance measures. Comparison between the computational results shows that the proposed algorithm outperforms the performance of the classical linear optimal control algorithm for the actively controlled building.

Performance evaluation of a fuzzy variable structure satellite attitude controller under sensor data delay

One of the main sources of uncertainties in controlling the attitude of a satellite is the time delays seen in sensor data. Although it is possible to process sensor data to correct the deficiencies caused by delays, it is more suitable to design the controller robust enough to handle uncertainties well. In this study, the attitude of a 3-degrees of freedom satellite model, incorporating uncertainties (both sensor data delay and actuator misplacements), is controlled using a suitably designed fuzzy variable structure controller (FVSC). The performance of the FVSC is evaluated and compared to that of other reference controllers [proportional-derivative (PD), linear-quadratic-Gaussian (LQG), and loop-shaping controllers (LSCs)]. The FVSC performs well in both nondelayed and delayed (T_d = 0.2 s and 0.4 s) cases, while the PD and LQG controllers provide good response only for nondelayed cases (i.e. T_d = 0 s). A robust LSC also performs well in both cases, but its root mean squared error is high compared to the FVSC in the delayed case.

Field Experimental Evaluation of Null Control Performance of MU-MIMO Considering Smart Vertical MIMO in LTE-Advanced Downlink under LOS Dominant Conditions

Field Experimental Evaluation of Null Control Performance of MU-MIMO Considering Smart Vertical MIMO in LTE-Advanced Downlink under LOS Dominant Conditions

An Improved MRAC Scheme for Non-linear Design of Adaption Gain γ using Heuristic Algorithms

This paper presents an approach to Optimal Model Reference Adaptive Control (OMRAC) and comparative performance evaluation are analyzed for a conical tank process which exhibits behavior of a class of nonlinear dynamical system. The conventional Model Reference Adaptive Control (MRAC) method based on the MIT rule reported in the works (P. Swarnkar et al., 2010), has its difficulty in choosing the reference model and adaption gain γ. Inspired by the above work, the selection of reference models in MRAC scheme are based on the multiple models (MM) depending on the operating regime of the process. In this proposed work, the reference model considered is a second order system having fixed roots in denominator polynomial representing the most dominant poles in the process determined using Dominant Pole Algorithm (DPA). The numerator polynomial of the reference model is designated as static sensitivity from each linearized region of the process. The optimal adaption gain γ of MRAC is obtained by Bacterial Foraging based Particle Swarm Optimization (BFPSO) algorithm and the system performance is compared with traditional algorithms such as Bacterial Foraging Optimization (BFO) and Particle Swarm Optimization (PSO). The simulated result gives consistently better setpoint tracking mechanism and error minimization.

Money versus Time: Evaluation of Control Performance based on Convenience and Energy Consumption

Flow control techniques for turbulent drag reduction in internal flows are typically evaluated under two alternative flow conditions, i.e. at constant mass flow rate or constant pressure gradient. Successful control leads to reduction of drag and pumping power at constant mass flow rate, whereas constant pressure gradient leads to an increase of the mass flow rate and pumping power. In practical applications, however, a compromise between the energy consumption and the corresponding convenience (flow rate) achieved with that amount of energy has to be reached so as to accomplish a goal which in general depends on the specific application. Based on this idea, we describe the derivation of two dimensionless parameters which quantify the total energy consumption and the required time (convenience) for transporting a given volume of fluid through a given duct. Performances of existing drag reduction strategies are re-evaluated within the present framework.

Workspace‐Based Controller Design and Performance Evaluation of MDOF Force Sensorless Bilateral System

SUMMARYRedundant multi‐degree‐of‐freedom (MDOF) bilateral system in workspace is expected to be a key technology for the development of next‐generation robots because of the variety of feasible tasks. Nowadays, four‐channel bilateral structures based on acceleration control have been introduced to realize both position and force tracking in a bilateral control system. Additionally, torque observers have been implemented to facilitate force feedback without the use of torque/force sensors. However, differences in controller composition between the joint space and workspace are still unclear. In particular, observer designs in both spaces are important for a realization of torque/force sensorless bilateral control. This paper presents a performance evaluation of an MDOF force sensorless bilateral system performed by considering the design space of observers by numerical and experimental analyses. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 186(4): 70–80, 2014; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22481

Performance evaluation of optimal PI controller for ALSTOM gasifier during coal quality variations

Coal gasifier, an essential part of Integrated Gasification Combined Cycle (IGCC) converts coal into synthesis gas (syngas or producer gas) under certain pressure and temperature. The quality of syngas is highly influenced by quality of coal (calorific value) and hence greatly affects the power generation. Gasifier control seems to be highly difficult since it involves many variables and inherent nonlinearity. The baseline PI controller provided with ALSTOM benchmark challenge II (benchmark model of coal gasifier) fails to satisfy the constraints at 0% load for sinusoidal pressure disturbance and coal quality variations (±18%). This paper evaluates the tuning parameters of ALSTOM benchmark challenge II using Multi-Objective Particle Swarm Optimisation (MOPSO) algorithm. Robustness of the optimal PI controller is tested under sinusoidal and step pressure disturbance tests at 100%, 50% and 0% load conditions with decreased and increased coal quality variations. Test results show that the optimal PI controller meets all the constraints comfortably at all load conditions and provides better results for coal quality variations.

Repulsive force control of minimally invasive surgery robot associated with three degrees of freedom electrorheological fluid-based haptic master

This paper presents a repulsive force feedback control in a haptic master–slave robot-assisted system for robot minimally invasive surgery. In general, the haptic master can provide position and force information for superior performance and reliability in master–slave robot-assisted interventions for a surgeon. In order to realize this potential, in this work three degrees of freedom electrorheological haptic master is adopted and associated with a four degrees of freedom slave robot. The haptic master featuring controllable electrorheological fluid is featured by a spherical joint mechanism and the slave robot is controlled by servomotors. After designing a user interface that is capable of providing force feedback in all the degrees of freedom available during robot minimally invasive surgery, the dynamic model of the haptic master is analyzed and the model parameters are identified to evaluate control performance of the haptic master on skin- and cancer-like tissues (palpation). Subsequently, the haptic architecture for robot minimally invasive surgery is established and experimentally implemented so that the reflection force for the object of the slave robot and the desired position for the master operator are transferred to each other. In order to demonstrate the effectiveness of the proposed system, repulsive force tracking control performances are evaluated and presented in time domain.

Control Performance Evaluation to Avoid Pounding of Bridges

Earthquake inflicts damage on bridges in various ways. In this research an experimental study was carried out to decrease the damage caused by the pounding of bridges as earthquake load was added. For the experiment, we designed a model of successive bridge composed of a reinforced concrete bridge top and I section steel. At each bridge pier was placed a rubber bearing which was frequently used for seismic isolation. As for damper, we ourselves designed and produced a MR damper of 30 KN. Five experimental conditions were given ranging from without damper, with damper but no electricity input, with damper and electricity input, each with two different algorithms. For the experiment, we inflicted a 50% reduced wave of Kobe earthquake horizontally on the model, and compared the displacements and power data under each condition. The result proved that the MR damper of our own design was effective to prevent the successive bridge model from colliding by exerting a sizable amount of influence on its displacement and power data.