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This paper studies the global regulation problem by a non-predictor event-triggered controller for high-order feedforward nonlinear systems with unknown time-varying delays in the states and input. We propose a non-predictor-based event-triggered controller with a dynamic gain-scaling factor, in which any information on the delays is not required in controller design. The dynamic gain-scaling factor is utilised to deal with high-order terms so that the considered class of systems are generalised over the previous results. The simulation results effectively demonstrate the validity of our proposed control method. [ABSTRACT FROM AUTHOR]

In this paper, we consider a problem of global stabilisation of approximate feedback linearised systems with perturbed nonlinearity by an event-triggered control. We categorise the perturbed nonlinearity into three cases and obtain a characterisation function for each case. Then we propose an event-triggered controller with a gain-scaling factor along with an event-triggering condition which is developed based on the characterisation function. Utilising the system analysis results, we suggest a control parameter selection rule depending on the priority on either system output regulation speed or size of the interexecution times. Via practical examples, we demonstrate the validity of our control approach. [ABSTRACT FROM AUTHOR]

In this paper, we consider the global exponential stabilisation problem by output feedback for a class of nonlinear systems with the extended structure of nonlinearity over the existing control scheme. The new feature is that we present a newly designed reduced-order observer-based output feedback controller with a gain-scaling factor. In our proposed method, we provide more flexibility in the selection of control parameters by utilising a matrix inequality approach under the extended structure of nonlinearity. Using examples, we illustrate the improved results of the proposed control scheme over the existing control scheme. [ABSTRACT FROM AUTHOR]

In this paper, we consider a state feedback regulation problem for a class of high-order feedforward nonlinear systems in which there are delays in the state and input. Then, the feedback information is distorted such that the actually engaged controller is supposed to operate under measurement sensitivity. Both measurement sensitivity and delays are uncertain and time-varying. We propose a dynamic controller and analytically show that the controlled system is globally regulated in the presence of large and arbitrarily fast-varying measurement sensitivity and delays. The simulation results of the numerical and practical examples are presented to demonstrate the validity of our control method. [ABSTRACT FROM AUTHOR]

In this paper, the global regulation problem is considered for a class of high-order nonlinear systems with unknown time-varying delays. More specifically, the considered systems consist of a chain of power integrators with high-order nonlinearity and there are unknown input and state delays. From the system structural point of view, the high-order feedforward nonlinearity is further extended to include non-feedforward terms. In our controller design, our controller is a memoryless one which does not use any past input values such that any a priori information on time-varying delays is not needed. The global regulation of the controlled system is analyzed by using the Razumikhin theorem and adding a power integrator method. [ABSTRACT FROM AUTHOR]

The process of periodic sampling is investigated for a class of nonlinear systems. The objective is to achieve the longest sampling period that is compatible with a specified error bound. It is shown that there are robust optimal controllers that achieve this objective. It is also shown that the performance of such optimal controllers can be approximated by bang-bang controllers – controllers that are relatively easy to design and implement. [ABSTRACT FROM AUTHOR]

In this paper, a robust control scheme is proposed for a class of nonlinear systems which consist of uncertain time-varying parameters that are coupled with non-triangular terms, perturbed nonlinearity, and external disturbance. In order to deal with time-varying parameters, we provide determination process of allowed time-varying parameters utilising a Lyapunov equation. With system analysis associated with perturbed nonlinearity, we show that all states of the controlled system remain bounded by a gain-scaling feedback controller in the presence of external disturbance. Moreover, the ultimate bounds of some system states can be made (arbitrarily) small by adjusting a gain-scaling factor depending on the system nonlinearity. The effectiveness of our control scheme is shown via an application example, with comparison of the existing result. [ABSTRACT FROM AUTHOR]

The problem of designing robust optimal controllers to reduce in minimal time operating errors that had accumulated during a period of feedback loss is revisited, with the objective of imposing a constraint on the maximal overshoot of the controlled system. It is shown that robust optimal controllers that satisfy this constraint exist under rather broad conditions. It is also shown that optimal performance can be closely approximated by bang–bang controllers – controllers that are relatively easy to design and implement. [ABSTRACT FROM AUTHOR]

The problem of reducing operating errors after a feedback disruption is considered for a class of nonlinear delay-differential systems. It is shown that there are optimal controllers that reduce such errors in minimal time, once feedback has been restored. It is further shown that optimal performance can be approximated by bang-bang controllers – controllers that are easy to design and implement. [ABSTRACT FROM AUTHOR]

In this paper, a robust optimal control problem during feedback disruption is considered for a class of nonlinear systems which have been controlled by an observer-based output feedback controller. It is shown that during feedback disruption, there exists an optimal control input which keeps both system states and observer errors within a specified bound for the longest time. Then, it is shown that such an optimal control input can be practically implemented by using a bang-bang control input in terms of control performance. One numerical and one practical examples are given for clear illustration. [ABSTRACT FROM AUTHOR]

A robust control scheme with a gain-scaling factor is proposed for an extended class of nonlinear systems. Compared with many previous studies, our considered systems are more generalised by including uncertain parameters, perturbed nonlinearities, and external disturbance. With our control scheme, all states of the controlled system remain bounded. Moreover, it is shown that the ultimate bounds of some system states can be made (arbitrarily) small by adjusting the gain-scaling factor depending on the nonlinearities and external disturbance. The effectiveness of our control scheme is experimentally shown via its application in the control of an electromagnetic levitation system. [ABSTRACT FROM AUTHOR]

The problem of maintaining low operating errors during feedback outages is considered for a class of nonlinear systems with time-delays in the input channel. It is shown that there are optimal controllers that keep operating errors below a specified bound for the longest time possible. Furthermore, it is shown that optimal performance can be approximated as closely as desired by using bang-bang controllers – controllers that are relatively easy to calculate and implement. [ABSTRACT FROM PUBLISHER]

In this paper, we consider a control problem for a class of uncertain nonlinear systems in which there exists an unknown time-varying delay in the input and lower triangular nonlinearities. Usually, in the existing results, input delays have been coupled with feedforward (or upper triangular) nonlinearities; in other words, the combination of lower triangular nonlinearities and input delay has been rare. Motivated by the existing controller for input-delayed chain of integrators with nonlinearity, we show that the control of input-delayed nonlinear systems with two particular types of lower triangular nonlinearities can be done. As a control solution, we propose a newly designed feedback controller whose main features are its dynamic gain and non-predictor approach. Three examples are given for illustration. [ABSTRACT FROM PUBLISHER]

This paper generalises the several recent results on the control of feedforward time-delay nonlinear systems. First, in view of system formulation, there are unknown time-varying delays in both states and main control input. Also, the considered nonlinear system has extended feedforward nonlinearities. Second, in view of control solution, our proposed controller is a non-predictor feedback controller whereas smith-predictor type controllers are used in the several existing results. Moreover, our controller does not need any information on the unknown delays except their upper bounds. Thus, our result has certain merits in both system formulation and control solution perspective. The analysis and example are given for clear illustration. [ABSTRACT FROM PUBLISHER]

In this paper, we provide an output feedback solution over one given by Choi and Lim [Systems & Control Letters, 59(6), 374–379 (2010)] under more generalised system set-up. More specifically, we consider a stabilisation problem of a chain of integrators that has nonlinearity and an uncertain delay in the input by output feedback. The nonlinearity is classified into four types. Then, we propose a memoryless output feedback controller which contains a gain-scaling factor to adjust controller gains depending on the given nonlinearity type. Our stability analysis shows that the controlled system has unique stabilisation result associated with each type of nonlinearity. Our result provides a new aspect to the stabilisation problem of nonlinear time-delay systems and broadens the existing control results of time-delay systems. Two examples are given for illustration. [ABSTRACT FROM PUBLISHER]