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Autonomous swarm control, which is expected to be able to handle multiple unmanned vehicles (UxVs), is an important technology that can be applied to many operations and incorporated in many systems. For operations in real environments, we have to consider severe conditions under which communications between UxVs may be inadequate and the environment changes unexpectedly. In addition to optimality,...
This paper develops a multiple-model switching control based adaptive failure compensation scheme for hypersonic vehicles with some stuck actuators. The system uncertainties, caused by failures and unknown inertia parameters, are first parameterized. Then multiple adaptive dynamic estimators are designed, based on which, multiple adaptive control signals are designed using an error transformation...
In this paper an adaptive sliding mode control (SMC) law with self-regulated boundary layer is proposed. The design of the adaptive SMC considers practical issues as actuator limitation/saturation and error tolerance, which is given in terms of the boundary layer presented in real sliding mode. The existence of sliding motion is proved via Lyapunov analysis. Self-regulation to the best value of boundary...
The problem of spacecraft attitude tracking control for actuator faults/failures and external disturbances is addressed in this paper. Assuming that information on external disturbances is unknown, a finite time sliding mode (FTSM) control law is developed to handle actuator faults/failures. Under the constraint conditions including the actuator faults and external disturbance, stability analysis...
We explore the use of adaptive control for a hydraulic actuator model in an engine with variable cam timing (VCT) system. The hydraulic actuator is modeled as a Hammer-stein system with an asymmetric, uncertain input nonlinearity followed by known time delay and linear dynamics. We begin the presentation by designing a fixed-gain baseline controller, which consists of a PI controller with high robustness...
Quadrotors, like any dynamical system, are subjected to model uncertainties which may cause instability and inaccuracy in navigation. In addition, the presence of input constraints violates the affine property which, as a result, adds additional challenges and complicates designing the control system for quadrotors. In this paper, an adaptive nonlinear control algorithm is designed to overcome these...
Proportional-integral-derivative (PID) controller is popular algorithm in structure vibration control. In order to maintain minimum regulation error, the PID control require big proportional and derivative gains. The control performances are not satisfied because of the big uncertainties in the buildings. In this paper, the type-2 fuzzy system is applied to compensate the unknown uncertainties, and...
The design of adaptive sliding mode control is studied for a class of Markov jump systems(MJSs) with transition rate uncertainties and the partial failures of the actuators. Firstly, the mathematical model of MJSs with the uncertainty of the transition rate and the partial failure of the actuator is established. Secondly, the sliding surface is proposed by combining linear matrix inequality (LMI)...
A novel actuator fault reconstruction scheme based on neural network and adaptive sliding mode observer is presented for a class of nonlinear systems with uncertainty. To improve the accuracy of actuator fault reconstruction, the radial basis function neural network is applied to approximate the uncertainty on line. An adaptive algorithm is designed to modify the gain of the controller by considering...
The problems of fault-tolerant control and fault estimation for descriptor systems with actuator faults are addressed. A nonfragile observer is proposed to estimate the states of the descriptor system and reconstruct actuator faults. Subsequently, based on the estimation information provided by the observer, the nonfragile fault-tolerant controller is built to guarantee the admissibility of the closed-loop...
In this paper, a composite integral terminal sliding mode surface is developed, and an adaptive synchronization control scheme is proposed accordingly for multiple robotic manipulators with actuator saturation. By combining the terminal sliding mode with integral terms, the presented scheme is able to reduce the static tracking errors and improve the synchronization performance. Moreover, the system...
In the paper, we address the attitude control and momentum management problem of the spacecraft with patrial sate information. A three-axis coupled nonlinear dynamics subject to various uncertainties is investigated, and the ADRC technique is applied. The proposed control scheme synthesizes a linear quadric regulator controller, a ΜΙΜΟ-type extended state observer and a novel compensator, which only...
This paper investigates the receding horizon H∞ guaranteed cost control for a class of norm-bounded uncertain systems subject to actuator saturation. A sufficient condition for the existence of the controller is proposed to handle the amplitudes of control input signals and guarantee both of the H∞ norm and quadratic cost performance for all admissible uncertainties and external disturbances. Furthermore,...
This paper presents a synthetic jet actuator (SJA)-based closed-loop active flow control and estimation method, which compensates for the parametric uncertainty inherent in SJAs. A proper orthogonal decomposition (POD)-based model reduction technique is first utilized to recast the Navier-Stokes partial differential equation as a set of ordinary differential equations in terms of the unknown Galerkin...
We apply formal methods to lay and streamline theoretical foundations to reason about Cyber-Physical Systems (CPSs) and cyber-physical attacks. We focus on integrity and DoS attacks to sensors and actuators of CPSs, and on the timing aspects of these attacks. Our contributions are threefold: (1) we define a hybrid process calculus to model both CPSs and cyber-physical attacks. (2) we define a threat...
A cyber-physical system (CPS) typically utilizes networks of computers and communication systems to automatically monitor and manage the interactions and data exchanges between plant, sensor, controller and actuator elements within the CPS. The design and implementation of such a CPS are particularly challenging due to their requirements of high reliability and resiliency to possible components' failure...
The paper addresses a problem of quadrotor unmanned aerial vehicle (so-called X4-flyer or quadrocopter) utility model identification for control design purposes. To that goal the quadrotor model is assumed to be composed of two abstracted subsystems, namely a rigid body (plant) and four motors equipped with blades (actuators). The model of the former is acquired based on a well-established dynamic...
This paper presents a fault-tolerant control (FTC) with integration of neural network (NN) and multivariable sliding mode approaches for an air-breathing hypersonic vehicle (AHV), where both partial loss of effectiveness faults and bias faults in actuators are considered. A radial bias function NN (RBFNN) is derived using on-line updating law to approximate the lumped uncertainties, which consists...
A novel control scheme is presented in this work to address the attitude stabilization problem in the presence of actuator saturation, misalignment and lack of inertia information. Taking a hyperbolic tangent function in its formulation, the control signal explicitly obeys a known maximum-torque constraint. Considering the possible actuator misalignment, a dynamic attitude gain is introduced to accommodate...
In this paper, a nonlinear adaptive super-twisting sliding mode fault tolerant controller is proposed for an uncertain MIMO aircraft system in the present of actuator malfunctions. The dynamics of aircraft attitude motion are divided into outer-loop subsystem and inner-loop subsystem. On this basis, the controllers are designed respectively to ensure the finite-time convergence. Through the online...
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