Output Tracking Performance Research Articles

Output tracking control with enhanced damping of internal dynamics and its output boundedness for static synchronous compensator system

This study investigates an important and challenging problem in non-linear systems: achieving output tracking control with a tolerable error bound as well as providing enhanced damping control of the internal dynamics. This problem is solved by using a damping controller in an input-output linearised static synchronous compensator system. The controllability and observability analyses direct the authors how to determine the damping controller gain. The proposed controller provides improved damping for lightly damped internal dynamics with degraded but tolerable output tracking performance. Finding a parameter-dependent Lyapunov function for the zero dynamics of error dynamics proves the stability of the damped internal dynamics in the time-invariant and time-varying systems. Stability of the closed-loop system is established by designing a composite Lyapunov function and it ensures that the tracking error of the output, in the approximated input-output linearised system, remains within a specified bound. Through stability analysis, the damping controller and the desired reference trajectory providing uniform boundedness of tracking error in output can be designed.

Robust iterative learning control via continuous sliding-mode technique with validation on an SRV02 rotary plant

This paper is to present a new design of robust Iterative Learning Control (ILC) for the purpose of output tracking using continuous sliding mode technique. The main feature of the design is that the controller signal is continuous due to the use of integral and employment of second-order sliding mode technique. The proposed ILC is more robust to noises and disturbances than the saturation approximation of the traditional sliding mode control because the control amount required to maintain the region of convergence is less. The robust ILC is suggested and the convergence of output-tracking error is also proven. The experimental results have clearly exhibited the excellent output-tracking performance by the continuous second-order sliding-mode-based robust iterative learning control.

Operator-based actuator fault detection system design of a thermal process

In this paper, an operator-based fault detection method for actuator fault of an aluminium plate thermal process is proposed by using operator-based robust right coprime factorisation (RCF) approach. In details, operator-based output tracking and fault detection system design for single input single output (SISO) system is proposed, then the theoretical analysis is extended to multi input multi output (MIMO) system. Based on the proposed design schemes, the output tracking performance can be realised and the actuator fault can be detected. After developing a mathematical model of the three-input three-output aluminium plate thermal process, the proposed design schemes are applied and the effectiveness of that is confirmed by the simulation results.

Operator-based robust control of MIMO aluminium plate thermal process

In this paper, operator-based robust control for Multi-Input Multi-Output (MIMO) aluminium plate thermal process is considered. In detail, a 3-input 3-output aluminium plate temperature control process is demonstrated and the model of the process is given. For considering the robust control of MIMO non-linear system, one class of operator-based MIMO system is described and the control system design is given. Based on the proposed design scheme, the system is robustly stable and the desired output tracking performance can be realised. Finally, the theoretical analysis is applied onto the 3-input 3-output aluminium plate temperature control process and the effectiveness of the theoretical analysis is demonstrated by the simulation and experimental results.

Operator-based parallel compensation control for hysteresis using ELM-based PI model

In order to describe the hysteresis, play-type Prandtl-Ishlinskii (PI) hysteresis model is applied in this paper. For compensating the effect of hysteresis which precedes plants, an extreme learning machine (ELM)-based parallel compensator is designed by using properties between play and stop hysteresis operators. Based on the compensated plants, according to operator-based right coprime factorisation, a feedback controller and a tracking controller are designed to guarantee the output tracking performance. Finally, the numerical simulation results are presented to validate the effectiveness of the proposed method.

Operator-based robust control for MIMO non-linear systems with uncertain hysteresis

This paper presents a robust control method for multi-input multi-output (MIMO) non-linear systems with uncertain hysteresis using operator-based robust right coprime factorisation approach. In details, a new operator-based robust control system design is proposed for MIMO non-linear plants preceded by hysteresis and some sufficient conditions are proposed. By using the obtained conditions, the controlled system is robustly stable and the desired output tracking performance can be realised. Finally, simulation is done to validate the effectiveness of the proposed control design method.

Adaptive Compensation of Unknown Actuator Failures for Strict-feedback Systems

Actuator failures are inevitable in practice especially in complex systems. The unknown failure may cause instability and catastrophic accidents during operation of control systems. A state feedback control scheme is proposed by using backstepping techniques. Compared with exist results, The uncertainties caused by total failure are seen as the bounded term and an estimator is designed to estimate its upper bound. The stability of closed loop system and output tracking performance can be guaranteed by our control law and corresponding update laws of uncertain parameters.

Adaptive Friction Compensation for Mechanical Systems with Unknown Deadzone

Friction exists in a wide range of physical systems. On the other hand, deadzone hysteresis nonlinearities seem inevitable in practice especially in mechanical system. In this paper, a class of mechanical systems with dynamic friction and unknown deadzone hysteresis are considered . A state feedback control scheme is proposed by using backstepping techniques. In this control scheme, an approximation of deadzone model is constructed and we use a linear part and a bounded part to approximate hysteresis input. The stability of closed-loop system and output tracking performance can be ensured by this control law and update laws of unknown parameters and the upper bound of external disturbance.

Integrated Direct/Indirect Adaptive Robust Control of Hydraulic Manipulators With Valve Deadband

In this paper, an integrated direct indirect adaptive robust control (DIARC) algorithm is proposed for an electro-hydraulic manipulator with unknown valve deadband to improve the achievable output-tracking performance. The controller design for such a system is nontrivial due to various factors, such as nonsmooth static and Coulomb friction model uncertainties arising from the use of a simplified proportional-flow-valve model, and other unknown disturbances present in the system. Furthermore, when an unknown input-valve deadband is present, the controller performance can deteriorate if it is not taken care of explicitly. This paper recognizes the fact that though unknown valve deadband nonlinearity is not globally linearly parameterizable, it can still be linearly parameterized during most of the working ranges. Hence, by using an indirect estimation algorithm with online condition monitoring, accurate estimates of the unknown deadband parameters are obtained for an improved control performance. Comparative experimental results for motion control of an electro-hydraulic manipulator with two different valves having deadband illustrate the effectiveness of the proposed algorithm.

Reference output tracking control for a flexible air‐breathing hypersonic vehicle via output feedback

SUMMARYThis paper addresses the problem of reference output tracking control for the longitudinal model of a flexible air‐breathing hypersonic vehicle (FAHV) by utilizing the output feedback control approach. The dynamic characteristics of the FAHV along with the aerodynamic effects of hypersonic flight make the flight control of such systems highly challenging. Moreover, there exist some intricate couplings between the engine and flight dynamics as well as complex interaction between rigid and flexible modes in the longitudinal model. These couplings bring difficulty to the flight control design for the intractable hypersonic vehicle systems. This paper deals with the problem of reference output tracking control for the longitudinal model of the FAHV. By utilizing the trim condition information including the state of altitude, velocity, angle of attack, pitch angle, pitch rate and so on, the linearized model is established for the control design objective. Then, the reference output velocity and altitude tracking control design problem is proposed for the linearized model. The flexible models of the FAHV system are hardly measured because of the complex dynamics and the strong couplings of the FAHV. Thus, by using only limited flexible model information, the reference output tracking performance analysis criteria are obtained via Lyapunov stability theory. Then, based on linear matrix inequality optimization algorithm, the static output feedback controller is designed to stabilize the closed‐loop systems, guarantee a certain bound for the closed‐loop value of the cost function, and can make the control output achieve the reference velocity and altitude tracking performance. Subsequently, the condition of dynamic output feedback controller synthesis is given in terms of linear matrix inequalities and a numerical algorithm is developed to search for a desired dynamic output feedback controller which minimizes the cost bound and obtains the excellent reference altitude and velocity tracking performance simultaneously. The effectiveness of the proposed reference output tracking control method is demonstrated in simulation part. Furthermore, the superior reference velocity and altitude performance commands could be achieved via using static and dynamic output feedback controllers under lacking some unmeasured flexible states information in the measurement output vector. Copyright © 2011 John Wiley & Sons, Ltd.

Operator-based robust control design for nonlinear plants with perturbation

In this article, operator-based robust control design for nonlinear plants with perturbation is considered by using robust right coprime factorisation approach. In detail, the property of unimodular operator is studied, and a control design structure is proposed. Based on the proposed design scheme, the designed system is robustly stable. Also, output tracking performance can be realised simultaneously. Finally, the effectiveness of the proposed design scheme is demonstrated by a simulation example.

Operator-based robust control for nonlinear systems with Prandtl–Ishlinskii hysteresis

This article presents an operator-based robust control method for nonlinear systems with Prandtl–Ishlinskii (PI) hysteresis. On the existence of the hysteresis, the system usually exhibits undesirable oscillations and even instability. While addressing the hysteresis, PI model is adopted to describe it. Especially, the PI model is decomposed into two terms: an invertible part and a disturbance part. In this way, the invertible part could be considered as a part of the nonlinear system. Based on the concept of Lipschitz's operator and the robust right coprime factorisation condition, a robust control design scheme is given to guarantee the bounded input bounded output stability of the obtained system. Further, a tracking operator design method is given to ensure the control system output-tracking performance under the existence of the disturbance part. Numerical simulation results are presented to validate the effectiveness of the proposed method.

Operator-based output tracking control for non-linear uncertain systems with unknown time-varying delays

In this paper, operator-based output tracking control for non-linear uncertain systems with unknown time-varying delays is considered by using the robust right coprime factorisation approach and delay compensating operator. The property of the time-varying delays is analysed in detail, and a delay compensating operator is designed. Based on the proposed design scheme, the output tracking performance is realised. Also, an example about the temperature control process of an aluminium plate with Peltier element actuator is given to demonstrate the validity of the theoretical analysis, and the effectiveness of the proposed design scheme is also confirmed by the simulation results.

Robust Output Feedback Control of a Class of Nonlinear Systems Using a Disturbance Observer

This paper considers the output-tracking control problem of feedback linearizable nonlinear systems in the presence of external disturbances and modeling errors. A robust output feedback nonlinear controller is designed to achieve excellent output-tracking performance. By exploiting the cascade features of backstepping design, a simple disturbance observer (DOB) is proposed to suppress the effects of the uncertainties, and a high-gain observer (HGOB) is applied to estimate the unmeasureable states of the system. Although the DOB-based controllers are usually designed according to linear control theory, in this study, strict analysis of the nonlinear control system is given. Experimental results on a magnetic levitation system are provided to support the theoretical results and to verify the advantages of the proposed controller.

H-Infinite Output Tracking Control for Neutral Systems with Time-Varying Delay and Nonlinear Perturbations: A Less Conservative Result

The problem of H-Infinite output tracking control for liner neutral systems with time-varying and nonlinear perturbations is investigated. The purpose of this paper is to ontain a delay-dependent sufficient condition to guarantee H-Infinite output tracking performance and a less conservative result. A liner matrix inequality (LMI) approach is adopted to solve the problem.

Operator-based non-linear control system design for unstable plants with input saturation

Operator-based robust right coprime factorisation approach is an interesting approach for non-linear control. It provides an effective framework for non-linear unstable system. In practice, the input constraint always exists, which induces that the real control input is different from the controller output, thus the input constraint may destabilise the system. However, control system design for non-linear plants with input saturation has seldom been studied due to the difficulties in dealing with non-linearity. Also in operator-based robust right coprime factorisation method, input saturation is not considered. In this paper, a new control system design for non-linear unstable plants with input saturation is proposed. Based on the robust right coprime factorisation, an operator-based switching controller is designed, which avoids the unstable region. Moreover, based on the proposed design scheme, the output tracking performance is also realised, and the effectiveness of the proposed method is verified by simulation.

Output Feedback Adaptive Robust Learning Control of a Class of Nonlinear Systems with Periodic Disturbances

AbstractIn this paper, a discontinuous projection-based output feedback adaptive robust learning control (OARLC) scheme is constructed for a class of nonlinear systems in a semi-strict feedback form by incorporating an observer and a dynamic normalization signal. Since only output signal is available for measurement, an observer is firstly designed to provide exponentially convergent estimates of the unmeasurable states. Using certain known basis functions to capture the characteristics of unknown general periodic disturbances, the discontinuous projection type adaptation law can then be used to tune the amplitudes of those basis functions on-line to recover the unknown general periodic disturbances asymptotically. The estimation errors due to the unknown initial states, uncompensated disturbances, and the uncertain nonlinearities are also effectively dealt with via certain robust feedback at each step of the proposed OARLC backstepping design. The resulting controller achieves a guaranteed transient and a prescribed final tracking accuracy for output tracking performance. In addition, when the general periodic disturbances fall within the approximation ranges of the periodic basis functions, asymptotic output tracking performance is achieved as well.

Operator-based robust control for nonlinear plants with uncertain non-symmetric backlash

This paper presents an operator-based robust nonlinear control method for nonlinear plants with uncertain non-symmetric backlash. The control design is achieved by introducing operator-based robust right coprime factorization. In more detail, using an operator-theoretic approach, the uncertain non-symmetric backlash is described as a generalized Lipschitz operator and a bounded parasitic term. Since the generalized Lipschitz operator is unknown, a new robust condition using robust right coprime factorization is proposed to guarantee robust stability of the controlled plant with the uncertain backlash. As a result, based on the proposed robust condition, a stabilized plant is obtained. For eliminating the effect from the parasitic term to ensure the output tracking performance, a nonlinear tracking controller is designed. Simulation results are presented to validate the effectiveness of the proposed control design method. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society

Operator-based robust nonlinear control system design for MIMO nonlinear plants with unknown coupling effects

In this article, operator-based robust nonlinear control system design for multi-input multi-output (MIMO) plants with unknown coupling effects is considered. That is, by using operator-based robust nonlinear control design, coupling effects existing in the MIMO nonlinear plants can be decoupled based on a feedback design and robust right coprime factorisation approach, the coupling effects caused by controllers and plant outputs can be stabilised by using definition of Lipschitz operator and contraction mapping theorem, and output tracking performance can be realised by a tracking design scheme. Finally, a simulation example about temperature control process of 3-input/3-output aluminum plate is given to support the theoretical analysis.

Robust stability and tracking of non-linear systems with modified Prandtl-Ishlinskii hysteresis model

This paper introduces a method to guarantee robust stability of nonlinear systems with modified Prandtl-Ishlinskii (PI) hysteresis model and presents a tracking controller design method to compensate the effect of hysteretic non-linearity. In order to make hysteresis model closer to the real hysteretic behaviour, a modified PI hysteresis model which is described by a non-symmetric play operator with unknown slopes is adopted. Using an operator theoretic approach, the modified PI hysteresis model is represented as a generalised Lipschitz operator and a bounded parasitic term. To guarantee robust stability of the controlled systems with hysteresis, a robust condition using robust right coprime factorisation is used. To ensure the output tracking performance, a non-linear tracking controller is designed. Simulation results are presented to validate the effectiveness of the proposed control design method.