Transient Performance Specifications Research Articles

Survey of transient performance control

Control systems have played a key role in the advancement of technologies in almost every field. The technical competition in the fourth industrial revolution has now focused on high performance area. Transient performance control is the ultimate high-performance control and can serve applications such as flexible manufacturing, robots, UAVs, defense industry and medical systems. Rich modern control theories had been developed over the last few decades, and the majority of them are on stability related issues instead of performance. Actual applications lag the theories, causing so-called theory–practice gap. One key factor of the gap is scarcity of control design methods for transient performance. Transient performance control is to guarantee the transient performance specifications such as rise-time, overshoot and settling-time, which are truly demanded in practice. To promote transient performance control, this article reviews the control designs for transient performance, including finite-time stability and control, adaptive and prescribed performance control, and funnel control. The challenges and future research directions are addressed. The new solutions should be tested on typical industrial systems in benchmark against the existing control methods to show performance insurance and improvement of the former over the latter.

Robust yaw control of autonomous underwater vehicle based on fractional-order PID controller

Autonomous underwater vehicles (AUVs) have broad applications owing to their small size, low weight, strong ability to operate autonomously, and ability to replace humans in dangerous operations. AUV motion control systems can ensure stable operation in complex ocean environments and have attracted significant research attention in marine science and technology. The main difficulties with AUV motion control include the large uncertainties of dynamic and hydrodynamic characteristics and time delay of the signal transmission channel. In this study, we propose a robust fractional-order proportional–integral–derivative (FOPID) controller design for an AUV yaw control system. First, a three-dimensional stability region analysis method is proposed to achieve fractional orders. Unlike other stability region analysis methods, the proposed method is supported by theory instead of observation. Then, the other parameters are optimized according to the robust design specifications with respect to the parameter uncertainties. Therefore, the controlled system can tolerate different parameter uncertainties and fulfill transient performance specifications while maintaining system stability. The simulation results illustrate the superior robustness and transient performance of the proposed control algorithm.

Performance-Guaranteed Tracking Control of an Autonomous Surface Vessel With Parametric Uncertainties and Time-Varying Disturbances

In this paper, the model-based adaptive control combined with a continuous robust integral of the sign of the error (RISE) feedback strategy is presented for the trajectory tracking control of an autonomous surface vessel (ASV) subject to parametric uncertainties and time-varying disturbances. The control objective is to achieve asymptotic tracking and guarantee the transient tracking performance simultaneously. An adaptive feedforward term is used to compensate for the parametric uncertainties, and the effects generated by external disturbances can be overcome by a gain of the error sign term (a part of the RISE feedback term). In the previous RISE-based feedback control, the upper bounds of disturbances and their time derivatives are often required to be known, while the requirement is relaxed, in this paper, by rendering the gain of the error sign term adaptive. It should be noted that the adaptive gain of the error sign term adjusts automatically until it is sufficient to compensate for the disturbances, which helps to reduce the control effort. Moreover, the prescribed performance control technique is introduced to provide the transient performance specification of the tracking error, which guarantees the tracking performance and improves the robustness of the control system. Based on the backstepping procedure and the Lyapunov stability analysis, asymptotic trajectory tracking with transient tracking performance is theoretically guaranteed, and all the signals are shown to be bounded. The effectiveness of the proposed control scheme is demonstrated through the numerical simulation results.

A Novel Design of PI Current Controller for PMSG-Based Wind Turbine Considering Transient Performance Specifications and Control Saturation

This paper presents a novel design process of decoupled PI current controller for permanent magnet synchronous generator (PMSG)-based wind turbines feeding a grid-tied inverter through a back-to-back converter. Specifically, the design methodology consists of combining disturbance observer-based control (DOBC) with feedback linearization (FBL) technique to ensure nominal transient performance recovery under model uncertainty. By simplifying the DOBC under the feedback linearizing control, it is shown that the composite controller reduces to a decoupled PI current controller plus an additional term that has the main role of recovering the nominal transient performance of the FBL, especially under step changes in the reference. Additionally, an antiwindup compensator arises naturally into the controller when considering the control input saturation to design the DOBC. This permits removal of the effect of the saturation blocks required to limit the control input. The proposed control scheme is implemented and validated through experimentation conducted on 22-pole, 5 kW PMSG. The results revealed that the proposed technique can successfully achieve nominal performance recovery under model uncertainty as well as improved transient performances under control saturation.

Platoon Formation Control With Prescribed Performance Guarantees for USVs

This paper studies the platoon formation control problem for unmanned surface vehicles, in the presence of modeling uncertainties and time-varying external disturbances. The control objective is to make the vehicular platoons proceed along a given trajectory while maintaining a desired line-of-sight (LOS) range between each vehicle and its predecessor. To provide transient performance specifications on formation errors, including LOS range and angle errors, we enforce prescribed performance guarantees in the control design. The prescribed performance guarantees mean that formation errors evolve always within the predefined regions that are bounded by exponentially decaying functions of time. Using prescribed performance control methodology, neural network approximation, disturbance observers, dynamic surface control technique, and Lyapunov synthesis, we propose an adaptive formation control that ensures internal stability of closed-loop systems with guaranteed prescribed performance. Meanwhile, both collision avoidance and connectivity maintenance between two consecutive vehicles are guaranteed during the whole operation. The proposed formation control is decentralized in the sense that the control action on each vehicle depends only on information from its immediate predecessor. Simulation results demonstrate the performance of the proposed control.

Design and Simulation of a PID Controller for Motion Control Systems

Motion control system plays important role in many industrial applications among which are in robot system, missile launching, positioning systems etc. However, the performance requirement for these applications in terms of high accuracy, high speed, insignificant or no overshoot and robustness have generated continuous challenges in the field of motion control system design and implementation. To compensate this challenge, a PID controller was design using mathematical model of a DC motor based on classical root-locus approach. The reason for adopting root locus design is to remodel the closed-loop response by putting the closed-loop poles of the system at desired points. Adding poles and zeros to the initial open-loop transfer function through the controller provide a way to transform the root locus in order to place the closed-loop poles at the required points. This process can also be used for discrete-time models. The Advantages of root locus over other methods is that, it gives the better way of pinpointing the parameters and can easily predict the fulfilment of the whole system. The controller performance was simulated using MATLAB code and a reasonable degree of accuracy was obtained. Implementation of the proposed model was conducted using-Simulink and the result obtained shows that the PID controller met the transient performance specifications with both settling time and overshoot less than 0.1s and 5% respectively. In terms of steady state error, the PID controller gave good response for both step input and ramp.

Adaptive Finite-Time Controller Design for T-S Fuzzy Systems.

This paper studies the adaptive finite-time stabilization problem for a class of nonlinear systems described by Takagi-Sugeno (T-S) fuzzy dynamic models with parametric uncertainties. A novel adaptive state feedback control scheme for the T-S fuzzy systems is proposed, and the scheme is developed based on finite-time Lyapunov theorem and adaptive backstepping-like method. Augmented dynamics are introduced in the design of finite-time stabilization controllers to construct suitable finite-time Lyapunov functions. It is shown that finite-time convergence of the closed-loop adaptive control system can be achieved, and the potential controller singularity problem caused by the augmented dynamics can be avoided. In addition, constructive procedures to obtain such an adaptive finite-time controller are given. Convergence time as a transient performance specification is also taken into account, and a finite upper bound on the convergence time is estimated. Finally, two numerical examples are provided to illustrate the effectiveness and practicality of the proposed adaptive control approach.

Paralleled DC Boost Converters with Feedback Control using PSO Optimization Technique for Photovoltaic Module Application

3 E.E.Dept.,SVNIT,Surat ABSTRACT this paper a novel method of controller design for boost type dc-dc converter is proposed. DC/DC converters are widely used in photovoltaic generating systems as an interface between the photovoltaic panel and the load. Therefore, a better possible control technique is required in order to control the variation in output voltage of DC/DC converter due to the variation occurring in the external dynamics input parameters such as radiation, temperature and internal impedance of the photovoltaic (PV) module. In this paper, two paralleled DC/DC converter with a closed loop PWM based control is simulated to obtain constant output voltage. The optimal values of feedback PID controller are obtained using Particle Swarm Optimization Algorithm (PSOA). Extensive simulation result is found out with linear controller parameters and the same are presented here. Here comparison of the output of the PSOA based design and design of PID controller with transient performance specification (T-PID) for under- damped system is done. The PSO based tuning of PID controller is much better as determined by the simulation results.

Design of PI and PID controllers with transient performance specification

Proportional-integral-derivative (PID) controllers are widely used in industrial control systems because of the reduced number of parameters to be tuned. The most popular design technique is the Ziegler-Nichols method, which relies solely on parameters obtained from the plant step response. However, besides being suitable only for systems with monotonic step response, the compensated systems whose controllers are tuned in accordance with the Ziegler-Nichols method have generally a step response with a high-percent overshoot. In this paper, tuning methods for proportional-integral (PI) and PID controllers are proposed that, like the Ziegler-Nichols method, need only parameters obtained from the plant step response. The methodology also encompasses the design of PID controllers for plants with underdamped step response and provides the means for a systematic adjustment of the controller gain in order to meet transient performance specifications. In addition, since all the development of the methodology relies solely on concepts introduced in a frequency-domain-based control course, the paper has also a didactic contribution.

Parameter Sensitivity of Closed Loop System Response

The transient response of a linear feedback control system is characterised by the s plane pole positions of the closed-loop system transfer function, particularly by those of the dominant poles. During a design procedure these pole positions are changed by varying the parameters which are under the control of the designer until the transient performance specification of the system is satisfied. These pole positions can also change as a result of variations in system parameters not under the control of the designer, for example, due to component tolerances or environmental changes. A necessary part of the design procedure is therefore the determination of the sensitivities of the pole positions to system parameter variations. Insofar as the design procedure seeks to predict closed-loop system behaviour from open-loop system information it is desirable that these sensitivities are determined from the same information in order that sensitivity considerations may be introduced at an early stage. This may be accomplished by an extension of the complex frequency response method for feedback control system design.

Synthesis of control systems

FEEDBACK CONTROL SYSTEM DESIGN is most effective when both steady-state and transient performance specifications can be realized. One approach, synthesis, proceeds from a set of closed-loop specifications to an appropriate open-loop system which, upon closure of the feedback path, satisfies the specifications. Almost without exception, a compensation network must be used in conjunction with the fixed portion of the system G <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> (s). In many cases it is desirable that the compensation network consist of resistance and capacitance elements. To be R-C realizable, the poles of the transfer function describing the compensation network must be simple on the negative real axis, the origin and infinity excluded, i.e., its pole-zero excess must be equal to or greater than zero.

Synthesis of control systems based on approximation to a third-order system

IN RECENT YEARS the high-speed performance and accuracy demanded of military applications and industrial processes have placed increasing emphasis on the dynamic characteristics of control systems. However, system design is most effective when both steady-state and transient performance specifications can be realized. Ordinarily the designer works from the open-loop to the closed-loop specifications, i.e., trial-and-error modifications are made to the fixed portion of the system until a compensation network is found that eventually leads to an acceptable closed-loop performance. In contrast, another approach, synthesis, proceeds from the closed-loop specifications to an appropriate open-loop system, which upon closure of the feedback path, satisfies the specifications. The methods of Guillemin1 and Aaron2 accomplish this transition, but not without difficulties and complications which arise from the fact that a closed-loop transfer function must be selected that simultaneously: 1. exhibits a pole-zero excess equal to or greater than the excess of the fixed portion of the system, and 2. satisfies a set of closed-loop specifications. Recently, Aseltine3 introduced an inverse-root locus method that graphically determines the open-loop pole locations from a given closed-loop pole-zero configuration. However, none of these methods provides a simple procedure indicating how a closed-loop transfer function can be formulated directly from a detailed set of transient and steady-state specifications. This paper presents a quick and accurate method of synthesizing a linear, continuous, unity-feedback system from a set of specifications that eliminates the foregoing disadvantages. Attention is confined to a type I system that is compensated by an R-C realizable transfer function. To be R-C realizable, the poles of this function must be simple on the negative real axis, the origin and infinity excluded, i.e., its pole-zero excess must be equal to or greater than zero.