Proposed Hybrid Control System Research Articles

Robustification of the H[formula omitted] controller combined with fuzzy logic and PI&PID-F[formula omitted] for hybrid control of Wind Energy Conversion System Connected to the Power Grid Based on DFIG

This paper proposes a strategy for hybrid control of variable speed wind turbines connected to the electrical grid, using a Double Fed Induction Generator (DFIG). An efficient validation approach is presented in three steps. The first step concerns the comparison of performances between Fuzzy Logic (FL), H infinity (H∞) and Integral Proportional action (PI) controllers. In a system context based on the DFIG direct vector control structure, the strengths of H∞ are reinforced in the second step by implementing two new advanced mixed controllers, namely the FL-H∞ and the combination of the PI, the Proportional Integral Derivative (PID) action, the Filter Derivative (Fd) action and the H∞ (PI&PID-Fd)-H∞. The second step, based on a simplified system of indirect vector control structure of the DFIG, allows the performance of the (PI&PID-Fd)-H∞ to be compared with that of the FL-H∞. In contrast to the latter, it emerges that, in addition to its simplicity of implementation and the reduction in calculation and simulation time, the (PI&PID-Fd)-H∞ is very reassuring in terms of robustness against mixed uncertainties, stability, precision, tracking and decoupling between active (PS) and reactive (QS)power. This makes (PI&PID-Fd)-H∞ a very advantageous choice for the design of the proposed hybrid control system. The final step gives a more real-life picture of hybrid control of the wind system as follows, a random wind model is considered, an FL regulates the Maximum Power Point Tracking (MPPT) of the turbine model, the PI-H∞ and (PID-Fd)-H∞ control the Ps and Qs on the nominal DFIG model via a Rotor Side Converter (RSC), an FL regulates the DC-BUS voltage and the H∞ control the currents via a Grid Side Converter (GSC) and filter. According to the results, and in contrast to a conventional PI control system, the hybrid control system offered has very good performance, particularly with regard to, for example, optimal extraction of energy from the wind, the currents fed into the grid are well balanced, the Total Harmonic Distortion (THD) is reduced and the cos ϕ is almost equal to unity. In addition, a good compromise between stability and expected performance is ensured. Consequently, the proposed strategy has reasonable and very favourable advantages for the optimisation of energy conversion in grid-connected wind energy systems. The results are developed in the MATLAB/Simulink environment.

A XGBOOST‐MRFO control scheme for power quality improvement in grid integrated hybrid renewable energy sources using STATCOM

A hybrid control system is presented for the improvement of power quality in grid-integrated hybrid renewable energy sources (HRES) like hybrid photovoltaic-wind solar energy system using STATCOM. The proposed hybrid control system is the hybrid wrapper of both the extreme gradient boosting (XGBOOST) and Manta Ray Foraging Optimization (MRFO) and hence it is said to be as XGBOOST-MRFO control scheme. The innovation of the proposed hybrid system is the improved predictability through the participation of MRFO, reliability, adaptation for the entire parameter variations, and shorter implementation time. Depending on the minimal error objective function, MRFO improves the XGBOOST learning process. The proposed approach relies on XGBOOST-MRFO which is serving control algorithm to generate STATCOM reference signals. Here, the XGBOOST system is qualified with inputs like instantaneous previous power of the obtainable sources and the current time necessary load demand and the equivalent target reference power of the sources. Depending on the load variation, the XGBOOST-MRFO control scheme makes the gain parameters of the PI controller give the optimal control signal for the STATCOM and to direct the power of the HRES. The prediction process of the proposed system assumes the entire kinds of differences on system parameters such as DC voltage, real and reactive power. Therefore, the proposed XGBOOST-MRFO strategy gives that optimal control of STATCOM that attempts to recover the damping of the power system and direct line voltage by giving reactive power compensation. The proposed system is executed on the MATLAB platform and performance is evaluated. The performance of the proposed system is compared with existing methods.

Coupled Relative Orbit and Attitude Control Augmented by the Geomagnetic Lorentz Propulsions

An electrostatically charged spacecraft is subject to the Lorentz force and torque when moving in the geomagnetic field. By active modulation of the surface charge, the induced Lorentz force and torque can be used for orbit and attitude control, respectively. Because of the electromagnetic mechanism, the orbit and attitude motion of such spacecraft are naturally coupled, and the induced Lorentz force and torque are both instantaneously underactuated. Thus, other kinds of actuation are required to render the system fully actuated and controllable. A hybrid control system is then proposed in this paper for Lorentz-augmented spacecraft relative orbit and attitude control. The relative orbit motion is controlled by the combination of the Lorentz force and the thruster-generated control force, and the relative attitude motion is governed by the combination of the Lorentz torque and the magnetic torque. By using the adaptive backstepping control method, a closed-loop control scheme is designed for the hybrid control system to deal with the dynamic coupling, underactuation, unknown external disturbances, and model approximation errors simultaneously. The parameter adaptation laws are derived via the Lyapunov theory to guarantee the stability of the closed-loop system. Optimal distribution laws of the hybrid control inputs are then analytically solved. Finally, numerical examples are simulated in a -perturbed environment to verify the feasibility of the proposed hybrid control system and the validity of the closed-loop control scheme.

Improved hand prostheses control for transradial amputees based on hybrid of voice recognition and electromyography

The control of prostheses and their complexities is one of the greatest challenges limiting wide amputees' use of upper limb prostheses. The main challenges include the difficulty of extracting signals for controlling the prostheses, limited number of degrees of freedom (DoF), and cost-prohibitive for complex controlling systems. In this study, a real-time hybrid control system, based on electromyography (EMG) and voice commands (VC) is designed to render the prosthesis more dexterous with the ability to accomplish amputee's daily activities proficiently. The voice and EMG systems were combined in three proposed hybrid strategies, each strategy had different number of movements depending on the combination protocol between voice and EMG control systems. Furthermore, the designed control system might serve a large number of amputees with different amputation levels, and since it has a reasonable cost and be easy to use. The performance of the proposed control system, based on hybrid strategies, was tested by intact-limbed and amputee participants for controlling the HANDi hand. The results showed that the proposed hybrid control system was robust, feasible, with an accuracy of 94%, 98%, and 99% for Strategies 1, 2, and 3, respectively. It was possible to specify the grip force applied to the prosthetic hand within three gripping forces. The amputees participated in this study preferred combination Strategy 3 where the voice and EMG are working concurrently, with an accuracy of 99%.

Fuzzy adaptive robust proportional–integral–derivative control optimized by the multi-objective grasshopper optimization algorithm for a nonlinear quadrotor

Proportional–integral–derivative is one of the most applicable control methods in industry. Although it is simple and effective in most cases, it does not provide robustness against disturbances and may not perform well in cases with uncertainties and nonlinearities. In this study, a fuzzy adaptive robust proportional–integral–derivative controller is used to control a nonlinear 4 degree-of-freedom quadrotor. An adaptation mechanism is submitted to the proportional–integral–derivative controller for updating the proportional, derivative, and integral gains of proportional–integral–derivative control. Furthermore, a sliding surface is generated and submitted to the adaptation mechanism for better regulation of proportional–integral–derivative gains. Afterward, a fuzzy engine is applied to regulate the sliding surface for better performance of the adaptive proportional–integral–derivative when there are disturbance and uncertainties. The multi-objective grasshopper optimization algorithm is implemented on the control system for the regulation of the control system parameters to minimize the error and control effort of the proposed hybrid control system. Finally, the obtained results are presented for a nonlinear 4 degree-of-freedom multi-purpose (for marine, ground, and aerial maneuvers) quadrotor system designed and built in Sirjan University of Technology, Sirjan, Iran, to assure the effectiveness of this technique.

Hybrid PD-Fuzzy and PD Controllers for Trajectory Tracking of a Quadrotor Unmanned Aerial Vehicle: Autopilot Designs and Real-Time Flight Tests

This paper presents a hybrid nonlinear control system, comprising of a conventional proportional-differential (PD) controller and a PD-type fuzzy logic autopilot for the trajectory tracking of a quadcopter drone. Given the inherent nature of traditional control, which is model-based, and the essence of fuzzy logic control, which is knowledge-based, the proposed hybrid controllers can provide a more robust solution in the face of uncertainties. Both controllers operate in a parallel incremental form to improve the transient performance and the robustness of the closed-loop control system. Through extensive computer simulations supported by real-time flight tests, this paper highlights the efficacy of the proposed hybrid control system in the presence of some parameter variations, nonlinear aerodynamic models, and some external disturbances (e.g., wind gusts). The Dryden and 1–cos turbulence models are employed to represent the effects of wind gusts under realistic flight environments. The stability analysis of the closed-loop control system is conducted using Lyapunov’s indirect method.

A comparison between the minimum-order & full-order observers in robust control of the air handling units in the presence of uncertainty

Control of the air-handling units (AHU) is required to maintain satisfactory comfort conditions with low energy consumption. In the case of failure in sensor fusion systems of AHUs, full-order observers can be used as the supportive tool to provide an acceptable estimation of state variables. In this paper, a multivariable nonlinear model of the AHU is considered in the presence of uncertainties. The indoor temperature and relative humidity are controlled via manipulation of valve positions of air and cold water flow rates. In proposed hybrid control system, full and minimum-order observers are designed for the estimation of indoor temperature and relative humidity. Also, a regulator for disturbance rejection and a servo system for tracking objectives are presented. Minimum-order observers are designed when one or two states are available. The efficiency of full-order and two minimum-order observers in estimation, regulation and tracking objectives is compared for the nominal and uncertain models. Moreover, it is investigated that how the amount of model uncertainty affects the AHU performance and control inputs. It is generally predicted that when a minimum-order observer with two sensors is used, less control inputs are required. In addition, using full or minimum-order observers guarantees the robust performance of AHUs.

Intelligent Hybrid Control System Design for Antilock Braking Systems Using Self-Organizing Function-Link Fuzzy Cerebellar Model Articulation Controller

An antilock braking system (ABS) is designed to maximize wheel traction by preventing the wheels from locking during braking, while also maintaining an adequate ability to steer the vehicle. However, the performance of ABS is often degraded under harsh road conditions. In this paper, a self-organizing function-link fuzzy cerebellar model articulation controller (SOFFC) is proposed and is used as the uncertainty observer of the ABS. The self-organizing approach automatically generates and prunes the fuzzy rules for the SOFFC, without the need for preliminary knowledge. The learning algorithms not only extract the fuzzy rules for the SOFFC, but adjust the parameters of the SOFFC as well. A hybrid control system, composing a computational controller and a hyperbolic tangent compensator (HTC), is then proposed for the ABS. The computational controller, which contains an SOFFC uncertainty observer, forms the principal controller, and the HTC is used to compensate for the estimation uncertainty, in order to achieve ultimately bounded stability in the system. Finally, simulations are performed that demonstrate the effectiveness of the proposed hybrid control system in an ABS under various road conditions.

Self-Organized Connectivity Control and Optimization Subjected to Dispersion of Mobile Ad Hoc Sensor Networks

This paper addresses the problem of the connectivity control and the self-organized deployment/dispersion of a team of mobile ad hoc sensor nodes. First, to reduce redundant communication links while preserving global connectivity, a distributed link removal algorithm is developed that only requires local information of no more than two-hop neighbors. Secondly, for the purpose of preserving essential links while avoiding collisions, a combined piecewise-continuous motion controller is designed to regulate the motion of mobile sensors between two consecutive switches. The proposed hybrid control system can autonomously disperse a team of mobile sensors towards their final configuration with guaranteed connectivity and collision avoidance. Theoretical analysis and computer simulations have confirmed the efficiency and scalability of the proposed schemes.

Experimental Evaluation of Hybrid Truck Driving Torque Controller Considering Human-Vehicle System Dynamics

The key point of the research is to improve the eco-driving performance in a hybrid truck among various drivers. In the previous paper, the investigation relationship between the driver control parameters, driving performance and fuel economy showed a potential to improve fuel economy and reduce the dispersion of fuel economy among various driver model parameters by improving the vehicle longitudinal dynamics. Then a hybrid torque distribution controller with a driving torque feedback compensator improving the driving torque response and the automatic transmission controller considering gear changing speed has been proposed. The simulation studies showed that by using proposed hybrid control system both longitudinal dynamic performance and fuel economy can be improved among various driver model parameters. In this paper, the proposed hybrid control system has been verified by a driving simulator with several real drivers. The result indicates that the driving performance and fuel economy of the HEV among various drivers were improved by using proposed hybrid control system. The detail analysis of influence driving performance on fuel economy among all test drivers clarifying the effectiveness of proposed hybrid controller confirms that, the proposed hybrid controller has improved the e-co driving performance of each driver.

Hybrid recurrent cerebellar model articulation controller-based supervisory H∞ motion control system for permanent-magnet synchronous motor servo drive

This study proposes a hybrid supervisory H∞ control system using a recurrent cerebellar model articulation controller (RCMAC) for achieving high precision position tracking performance of permanent-magnet synchronous motor (PMSM) servo drive. The hybrid control system is composed of a RCMAC, a supervisory controller and a robust H∞ controller. The RCMAC is used as the main position tracking controller to mimic a perfect computed torque control law, and the robust H∞ controller is designed with adaptive bound estimation algorithm to compensate for the approximation error between the RCMAC and the ideal controller. The supervisory controller is designed based on the uncertainty bound of the PMSM to stabilise the system states around a predefined bound region and achieve satisfactory tracking performance. The online adaptive control laws are derived based on the Lyapunov stability analysis, so that the stability of the system can be guaranteed. A computer simulation is developed and an experimental system is established to validate the effectiveness of the proposed hybrid control system. All control algorithms are implemented in a TMS320C31 digital signal processor-based control computer. The simulated and experimental results confirm that the proposed hybrid control system grants robust performance and precise response regardless of load disturbances and PMSM parameters uncertainties.

Analysis of Vibration Control due to Strong Earthquakes

The paper proposes an aseismic hybrid control system to control the response of structures subjected to large ground motions caused by large magnitude earthquakes. The proposed hybrid control system consists of a base isolation system (laminated rubber bearings) connected to an active control system (a tuned mass damper and an actuator). The base isolation system is used to decouple the horizontal ground motions from the structure, whereas the active control system is used to protect the safety and integrity of the base isolation system. A 5-story benchmark building model is developed to study the effectiveness of the hybrid control system against different ground motions. It was found from the numerical results that rubber bearing system alone shows good performance and resists ground motion due to Hachinohe 1968, Kobe 1995, and Northridge 1994 earthquakes, but is somewhat unable to protect the model against El-Centro 1940 earthquake. After the installation of an active control system onto the rubber-isolated model, further improvements to earthquake resistance against these four earthquakes were observed, especially against the El-Centro earthquake. The merit of the hybrid control system lies in its capability to protect against different ground motions, with varying intensity and frequency content.

Hybrid Control of an Euler-Bernoulli Beam Using Direct Velocity Feedback and Wave-Filter-Based Active Wave Control

Active wave control strategy enables the inactivation of vibration mode, which is valid for suppressing the vibration of a distributed parameter structure. However, when active wave control is applied, new vibration modes are produced in the uncontrolled region. To overcome this problem, this paper proposes a novel control strategy based on a hybrid combination of direct velocity feedback (DVFB) and active wave control. The two control methods have complementary qualities; DVFB is for improving the stability, and active wave control is for its unique control effects. First, a transfer matrix method in the Laplace domain is introduced to describe wave propagation phenomena of an Euler-Bernoulli beam. Then the wave filtering method which uses point sensors is presented. Based on the filtering method, the characteristic equation and control laws of the reflected wave absorbing control are derived. Next, the independence of the two control methods in the proposed hybrid control system is investigated by a numerical simulation. This is followed by the discussion of the stability problem of the hybrid control system via a Nyquist diagram method and three types of root loci. Finally, the control effects of the proposed control system are presented, demonstrating the validity of the proposed method.

Hybrid fluid-dynamic control devices to attenuate slender structures oscillations

In the present work, a hybrid fluid-dynamic control system is proposed for the active/passive control of bending oscillations of tall and slender buildings under wind forces. The mathematical-numerical model of the hybrid system is developed from the classical tuned liquid column damper composed of one or more “ U ” tubes filled with fluid. When in motion the control system generates hydraulic forces which counteract the inertia forces induced by the dynamic loadings acting on the structure. Some of the main design aspects, dynamic properties and the resulting performance of the proposed hybrid control system as compared to those of the traditional liquid columns and tuned mass dampers for passive control are presented and discussed with the aid of the results obtained by using both analytical and FEM models together with comparisons between the uncontrolled and controlled responses of the structure having attached the proposed hybrid fluid-dynamic devices. Two examples of a practical application are presented to demonstrate the feasibility and performance of the hybrid control device in attenuating the bending oscillation amplitudes of slender structures of tall buildings under wind forces.

Passive and hybrid control systems for seismic protection of a benchmark cable-stayed bridge

In this paper, the effectiveness of passive dampers and a hybrid control system consisting of passive viscous dampers installed in parallel with semi-active dampers is investigated. Recently, the authors proposed an analytical model for long-period pulses in near-field ground motions. The effectiveness of passive dampers is investigated using the analytical pulses model and 44 recorded near-field ground motions. Numerical results show that the pulse model successfully captured the behavior of the bridge subject to near-field ground motions with pulse periods in the vicinity or larger than the fundamental period of the bridge. For this condition, passive dampers are quite effective. However, their effectiveness degrades significantly when the period of pulses is significantly smaller than the fundamental period of the bridge. A nonlinear semi-active controller based on optimal polynomial control theory has been developed for the proposed hybrid control system. In the proposed hybrid control systems, passive dampers continuously reduce the vibration of the bridge. Semi-active dampers are triggered only when the required control force to meet vibration control objectives exceeds the capacity of passive dampers installed in the bridge. Hence, the proposed hybrid control system not only reduces response quantities, but also protects passive dampers by reducing force demand on passive dampers during very strong earthquakes. The performance of the proposed hybrid control system has been investigated using 3 prescribed and 50 other ground motions. Numerical simulation results show that the proposed hybrid control system is quite effective in reducing peak response quantities of the bridge subject to impulsive type near-field ground motions. Simulation results also show that semi-active dampers are triggered only a few times during near-field ground motions. For far-field or long-period ground motions, e.g. Mexico earthquakes, only passive dampers are adequate to meet control objectives. Hence, notable advantages of the proposed hybrid control systems are the reduced use of external energy, lesser heating of the control devices and protection of passive system hardware during strong earthquakes. Copyright © 2005 John Wiley & Sons, Ltd.

04/01540 Characteristics of an improved heat-pump cycle for cold regions: Ma, G. and Chai, Q. Applied Energy, 2004, 77, (3), 235–247

Control of the air-handling units (AHU) is required to maintain satisfactory comfort conditions with low energy consumption. In the case of failure in sensor fusion systems of AHUs, full-order observers can be used as the supportive tool to provide an acceptable estimation of state variables. In this paper, a multivariable nonlinear model of the AHU is considered in the presence of uncertainties. The indoor temperature and relative humidity are controlled via manipulation of valve positions of air and cold water flow rates. In proposed hybrid control system, full and minimum-order observers are designed for the estimation of indoor temperature and relative humidity. Also, a regulator for disturbance rejection and a servo system for tracking objectives are presented. Minimum-order observers are designed when one or two states are available. The efficiency of full-order and two minimum-order observers in estimation, regulation and tracking objectives is compared for the nominal and uncertain models. Moreover, it is investigated that how the amount of model uncertainty affects the AHU performance and control inputs. It is generally predicted that when a minimum-order observer with two sensors is used, less control inputs are required. In addition, using full or minimum-order observers guarantees the robust performance of AHUs.

INTEGRATED PASSIVE-ACTIVE SYSTEM FOR SEISMIC PROTECTION OF A CABLE-STAYED BRIDGE

This paper presents an integrated passive-active (i.e. hybrid) system for seismic response control of a cable-stayed bridge. Since multiple control devices are operating, a hybrid control system could alleviate some of the restrictions and limitations that exist when each system is acting alone. Lead rubber bearings are used as passive control devices to reduce the earthquake-induced forces in the bridge and hydraulic actuators are used as active control devices to further reduce the bridge responses, especially deck displacements. In the proposed hybrid control system, a linear quadratic Gaussian control algorithm is adopted as a primary controller. In addition, a secondary bang-bang type (i.e. on-off type) controller according to the responses of lead rubber bearings is considered to increase the controller robustness. Numerical simulation results show that control performances of the integrated passive-active control system are superior to those of the passive control system and are slightly better than those of the fully active control system. Furthermore, it is verified that the hybrid control system with a bang-bang type controller is more robust for stiffness perturbation than the active controller with a μ-synthesis method, and there are no signs of instability in the over-all system whereas the active control system with linear quadratic Gaussian algorithm shows instabilities in the perturbed system. Therefore, the proposed hybrid protective system could effectively be used for seismically excited cable-stayed bridges.

Hybrid control for induction servomotor drive

The position control of an induction servomotor drive using a hybrid control system is studied. The design of a hybrid control system contains three parts: (i) the design of a computed torque controller that compensates for nonlinear effects and attempts to cancel nonlinear terms; (ii) the design of an adaptive fuzzy sliding-mode uncertainty observer to estimate all uncertainties that exist in the controlled system; and (iii) the design of a robust controller to dispel the effect of the minimum approximation error introduced by the uncertainty observer. All parameters in the hybrid control system are tuned in the sense of the Lyapunov theorem, thus the stability of the closed-loop system can be guaranteed. Simulated and experimental results verify that the proposed hybrid control scheme can achieve a favourable tracking performance and is robust with regard to parameter variations and external load disturbances. In addition, the advantages of the proposed hybrid control system are indicated in comparison with the traditional computed torque and sliding-mode control systems.

Hybrid computed torque controlled motor–toggle servomechanism using fuzzy neural network uncertainty observer

The dynamic response of a hybrid computed torque controlled toggle mechanism, which is driven by a permanent magnet (PM) synchronous servo motor, is studied in this paper. First, based on the principle of computed torque control, a position controller is developed for the motor–toggle servomechanism. Moreover, to relax the requirement of the lumped uncertainty in the design of a computed torque controller, a fuzzy neural network (FNN) uncertainty observer is utilized to adapt the lumped uncertainty on line. Furthermore, based on the Lyapunov stability a hybrid control system, which combines the computed torque controller, the FNN uncertainty observer and a compensated controller, is proposed to control the position of a slider of the motor–toggle servomechanism. The computed torque controller with FNN uncertainty observer is the main tracking controller, and the compensated controller is designed to compensate the minimum approximation error of the uncertainty observer instead of increasing the rules of the FNN. Finally, simulated and experimental results due to a periodic sinusoidal command show that the dynamic behaviors of the proposed hybrid control system are robust with regard to parametric variations and external disturbances.

Stability Analysis of an Hybrid Control Scheme Based on Discrete-Event Automata and Receding-Horizon Neural Regulators

A hybrid control scheme for nonlinear discrete-time systems is addressed. Such a scheme is composed of a continuous level characterized by a finite set of neural receding-horizon feedback control laws, and a discrete-event level aimed at choosing the best control action to be applied to the plant. At the continuous level, receding-horizon regulators based on neural approximators are used, whereas the discrete-event subsystem is represented by a new class of hybrid automata, namely, discrete-time discrete-event automata. In the paper, the stability analysis of the proposed hybrid control system is carried out.