Xuebo Yang

Data-Driven Adaptive Observer for Fault Diagnosis

This paper presents an approach for data-driven design of fault diagnosis system. The proposed fault diagnosis scheme consists of an adaptive residual generator and a bank of isolation observers, whose parameters are directly identified from the process data without identification of complete process model. To deal with normal variations in the process, the parameters of residual generator are online updated by standard adaptive technique to achieve reliable fault detection performance. After a fault is successfully detected, the isolation scheme will be activated, in which each isolation observer serves as an indicator corresponding to occurrence of a particular type of fault in the process. The thresholds can be determined analytically or through estimating the probability density function of related variables. To illustrate the performance of proposed fault diagnosis approach, a laboratory-scale three-tank system is finally utilized. It shows that the proposed data-driven scheme is efficient to deal with applications, whose analytical process models are unavailable. Especially, for the large-scale plants, whose physical models are generally difficult to be established, the proposed approach may offer an effective alternative solution for process monitoring.

Sampled-Data Control for Relative Position Holding of Spacecraft Rendezvous With Thrust Nonlinearity

This paper investigates the sampled-data control problem for spacecraft relative positional holding with limited thrust and thrust nonlinearity. The relative dynamic model is established based on the Clohessy-Wiltshire equations. Sector nonlinearity is employed to describe the nonlinear behavior of the chasers thruster. The relative position holding problem is regarded as a sampled-data output tracking control problem, and the disturbance attenuation for the closed-loop system is considered. By a Lyapunov approach, the controller design is cast into a convex optimization problem. Simulation results show the effectiveness and advantage of the proposed controller design method.

Fault-Tolerant Attitude Stabilization for Satellites Without Rate Sensor

A fault-tolerant control approach without rate sensors is presented for the attitude stabilization of a satellite being developed. External disturbances, reaction wheel faults, actuator saturation, and unavailable angular velocity are addressed. A sliding-mode observer is proposed by using attitude feedback only, and the unavailable angular velocity is estimated by this observer in finite time. Using the attitude and the estimated velocity, another sliding-mode observer is proposed to reconstruct actuator faults and disturbances. It is proven that reconstruction with zero observer error is achieved in finite time. With the reconstructed value, a velocity-free controller is then developed to asymptotically stabilize the attitude. Simulation results are also provided to verify the effectiveness of the proposed approach.

Allocation of Actuators and Sensors for Coupled-Adjacent-Building Vibration Attenuation

An actuator and sensor allocation approach is proposed for the design of coupled-adjacent-building vibration suppression under seismic excitation. This paper first establishes a full-order model of adjacent buildings with the location information of actuators and sensors. Then, the order of the model is reduced via modal cost analysis, by retaining the modes contributing the most. In view of the fact that the output powers of the actuators are limited, this paper brings forward a mixed H∞/GH2 control. By considering that not all the states of the system can be measured by the sensors, a dynamic output feedback controller is designed. The genetic algorithm is employed to obtain the locations of the actuators and sensors, as well as the corresponding controller. With the proposed approach, the allocation problem is solved, and the vibration of coupled adjacent buildings is attenuated at a sufficiently low level with constrained acting forces. Simulations demonstrate the effectiveness and robustness of the proposed approach in attenuating building vibration under earthquake excitation.

Robust Control for Autonomous Spacecraft Evacuation with Model Uncertainty and Upper Bound of Performance with Constraints

This paper studies the problem of guaranteed cost control for spacecraft evacuation. The relative dynamic model is established based on Clohessy-Wiltshire (C-W) equations. The paper has taken parameter uncertainty, output tracking, disturbance attenuation, and fuel cost into consideration. The paper introduces a new Lyapunov approach, so the controller design problem can be transferred into a convex optimization problem subject to linear matrix inequality (LMI) constraints. By using the controller, the spacecraft evacuation can be completed in a safe extent. Meanwhile, the fuel cost also has an upper bound. Then the paper analyzes the approach of evacuation and discusses possible initial states of the spacecraft for the controller design. An illustrative example is applied to show the effectiveness of the proposed control design method, and different performances caused by different initial states of spacecraft (-V-bar, -R-bar, and

Robust Adaptive State Constraint Control for Uncertain Switched High-Order Nonlinear Systems

Under the weaker conditions on system power and nonlinear functions, this paper focuses on the robust adaptive state constraint control for a class of uncertain switched high-order nonlinear systems. With the help of

A Novel Disturbance Estimation Scheme for Formation Control of Ocean Surface Vessels

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Robust Decentralized Adaptive Neural Control for a Class of Nonaffine Nonlinear Large-Scale Systems with Unknown Dead Zones

-times differentiable unbounded function, a robust adaptive state-feedback controller is designed by combining the homogeneous domination approach with parameter separation principle. When the initial condition satisfies a suitable requirement, it is shown that all signals of the closed-loop system are bounded and system state is within a prespecified limit range by the proposed controller. As a practical application, the design scheme is utilized to the continuous stirred tank reactor with two modes feed stream. To further demonstrate the efficiency of the proposed controller, another numerical example is given.

Recent Advances in Complex Networks Theories with Applications

To achieve high-accuracy formation control of multiple ocean surface vessels, the external disturbance acting on each vessel should be accommodated. In this paper, a novel disturbance estimation scheme is presented to solve this problem, and to provide the future formation controller design with precise estimation information. This approach is developed in the theoretical framework of a terminal sliding mode observer. The proposed observer is able to precisely estimate external disturbance after finite time. It is shown by Lyapunov stability analysis that the estimation error for external disturbance will converge to zero after finite time. A fast and precise estimation for external disturbance is achieved. Numerical example is further presented to validate the effectiveness of the developed disturbance estimation approach.

Swing-Up and Stabilization Control Design for an Underactuated Rotary Inverted Pendulum System: Theory and Experiments

The problem of robust decentralized adaptive neural stabilization control is investigated for a class of nonaffine nonlinear interconnected large-scale systems with unknown dead zones. In the controller design procedure, radical basis function (RBF) neural networks are applied to approximate packaged unknown nonlinearities and then an adaptive neural decentralized controller is systematically derived without requiring any information on the boundedness of dead zone parameters (slopes and break points). It is proven that the developed control scheme can ensure that all the signals in the closed-loop system are semiglobally uniformly ultimately bounded in the sense of mean square. Simulation study is provided to further demonstrate the effectiveness of the developed control scheme.