External Input Disturbance Research Articles

Anti-Disturbance Boundary Control for a Wave Equation With Input Disturbance

In this article, we investigate the exponential stabilization issue of a wave equation with the external input disturbance, which is described by a nonlinear exogenous system. A novel disturbance observer is constructed to estimate the unknown input disturbance. Then, based on the proposed disturbance observer, a boundary control strategy is developed to cancel the effect of disturbance and stabilize the system. The exponential stability is proven by employing the Lyapunov’s direct method. This method can be extended to a class of flexible systems described by the hyperbolic partial differential equation met in the practical engineer area. The example of a nonuniform flexible string system is given, where the effectiveness of the proposed strategy is evaluated based on simulations.

Torque Allocation of Hybrid Electric Trucks for Drivability and Transient Emissions Reduction

This paper aims at investigating powertrain behaviour, especially in transient dynamic responses, using a nonlinear truck vehicle dynamic model with a parallel hybrid configuration. A power split control was designed to achieve the desired drivability performance, with a focus on NOx emissions. The controller was characterized by high-level model-based logic used to elaborate the total powertrain torque required, and a low-level allocation strategy for splitting power between the engine and the electric motor. The final task was to enhance vehicle drivability based on driver requests, with the goal of reducing—in a hybrid configuration—transient diesel engine emissions when compared to a conventional pure thermal engine powertrain. Different parameters were investigated for the assessment of powertrain performance, in terms of external input disturbance rejection and NOx emissions reduction. The investigation of torque allocation performance was limited to the simulation of a Tip-in manoeuvre, which showed a satisfying trade-off between vehicle drivability and transient emissions.

Edge-based strict Lyapunov functions for consensus with connectivity preservation over directed graphs

In this paper we address the edge-agreement problem with preserved connectivity for networks of first and second-order systems under proximity constraints and interconnected over a class of directed graphs. We provide a strict Lyapunov function that leads to establishing uniform asymptotic stability of the consensus manifold with guaranteed connectivity preservation. Furthermore, robustness of the edge-agreement protocol, in the sense of input-to-state stability with respect to external input disturbances, is also demonstrated. These results hold for directed-spanning-tree and directed-cycle topologies, which are notably employed, respectively, in leader–follower and cyclic-pursuit control.

Stability Analysis for Stochastic Neutral Switched Systems with Time-Varying Delay

This paper addresses the problems of the input-to-state stochastic stability for neutral switched stochastic delay systems. Two switching signals in the input controller, including the external input disturbance, are considered: (1) the synchronous switching signal, which indicates that the switching signal of the input controller coincides with that of the controlled subsystems, and (2) the asynchronous switching signal, which signifies that two switching instants for the input controller and the subsystem are not identical. Irrespective of which switching signal exists in the input controller and the subsystem, multiple Lyapunov--Krasovskii functions, generalized delay integral inequality, and mode-dependent average dwell time are incorporated to analyze the underlying problem. Sufficient conditions based on two integral inequalities are obtained for these two cases, respectively. Also new and more relaxed Lyapunov monotonicity conditions are introduced. One simulation example is provided to demonstrate the effectiveness of the theoretical results.

Adaptive tracking control for networked control systems of intelligent vehicle

In this paper, the problem of tracking control of networked control systems of intelligent vehicle with external disturbance and network-induced disturbance is studied. A novel high-order adaptive discrete-time sliding-mode control (H-ADSMC) algorithm is proposed. Firstly, a high-order adaptive sliding-mode function on tracking error is constructed, in which the estimated external input disturbance is used as adaptive factor for the sake of reducing the effect of external disturbance. Then, the adaptive sliding-mode controller is obtained, and the convergence of sliding motion is proved. Furthermore, the network-induced disturbance acted on the output of sensor is considered. A new observer is designed to compensate the network-induced disturbance. Finally, the tracking error is analyzed, and the simulations are executed to verify the effectiveness of the proposed H-ADSMC algorithm and designed observer.

내부 모델 기반 외란 관측기를 이용한 수직 1축 머니퓰레이터의 속도 제어기 설계

This paper deals with a robust speed control problem of a vertical one-link manipulator in the presence of parameter uncertainties and unknown input disturbance. Uncertain load weight causes an additional sinusoidal disturbance in the rotation of the link. In order to improve the robustness against parameter uncertainties and external input disturbances, this paper employs an internal model-based disturbance observer approach. Comparative computer simulations are performed to test the performance of the proposed controller. The simulation results show the enhanced performance of the proposed method.

Optimal Pole Assignment for Discrete Linear Regulator With Deterministic Disturbances

This paper presents the solution of the linear discrete optimal control to achieve poles assigned in a circular region and, meanwhile, accommodate deterministic disturbances. It is shown that by suitable manipulations, the problem can be reduced to a standard discrete quadratic regulator problem that simultaneously ensures: 1) closed-loop-poles all inside a circle centered at (β, 0) with a radius α, where |β| + α ≤ 1, 2) minimizes the cost functional, and 3) accommodates external input disturbance.

Adaptive External Linearization Feedback Control for Flexible Link Manipulators: Robustness Analysis

The adaptive external linearization control proposed in [2], [3] was designed for a rigid link manipulator and was proved to be convergent and robust against external input disturbances. Our contributions, in the present communication, is to analyse its robustness against “unmodelled” high frequency modes (which can arise from flexibility, for instance).

Further study of the linear regulator with disturbances--The case of vector disturbances satisfying a linear differential equation

In a previous paper [1], the conventional optimal linear regulator theory was extended to accommodate the case of external input disturbances \omega(t) which are not directly measurable but which can be assumed to satisfy d^{m+1}\omega(t)/dt^{m+1} = 0 , i.e., represented as m th-degree polynomials in time t with unknown coefficients. In this way, the optimal controller u^{0}(t) was obtained as the sum of: 1) a linear combination of the state variables x_{i}, i = 1,2,...,n , plus 2) a linear combination of the first (m + 1) time integrals of certain other linear combinations of the state variables. In the present paper, the results obtained in [1] are generalized to accommodate the case of unmeasurable disturbances \omega(t) which are known only to satisfy a given \rho th-degree linear differential equation D: d^{\rho}\omega(t)/dt^{\rho} + \beta_{\rho}d^{\rho-1}\omega(t)/dt^{\rho-1}+...+\beta_{2}d\omega/dt + \beta_{1}\omega=0 where the coefficients \beta_{i}, i = 1,...,\rho , are known. By this means, a dynamical feedback controller is derived which will consistently maintain state regulation x(t) \approx 0 in the face of any and every external disturbance function \omega(t) which satisfies the given differential equation D -even steady-state periodic or unstable functions \omega(t) . An essentially different method of deriving this result, based on stabilization theory, is also described, In each cases the results are extended to the case of vector control and vector disturbance.