Finite-time consensus for second-order multi-agent systems with disturbances by integral sliding mode

Motivated by several accidents, attitude control of a spacecraft subject to faults/failures has gained considerable attention in a wider range of aerospace engineering and academic communities. This paper is concerned with industrial practices and theoretical approaches for fault tolerant control (FTC) and fault detection and diagnosis (FDD) in spacecraft attitude control system. An overview on recent development of spacecraft attitude FTC system design is presented. The basis of a FTC system is introduced. The existing engineering FTC techniques and theoretical methodologies, including their advantages and disadvantages, are discussed. Moreover, closely associated with the reliability-relevant issues, recent progress in attitude FTC design strategies is reviewed. A brief review of some open problems in the general area of spacecraft attitude control design subject to components faults/failures is further concluded.

A Review on Recent Development of Spacecraft Attitude Fault Tolerant Control System

This paper studies fault-tolerant control (FTC) designs based on nonsingular terminal sliding-mode control and nonsingular fast terminal sliding-mode control (NFTSMC). The proposed active FTC laws are shown to be able to achieve fault-tolerant objectives and maintain stabilization performance even when some of the actuators fail to operate. In comparison to existing sliding-mode control (SMC) fault-tolerant designs, the proposed schemes not only can retain the advantages of traditional SMC, including fast response, easy implementation, and robustness to disturbances/uncertainties, but also make the system states reach the control objective point in a finite amount of time. Moreover, they also resolve the potential singularity phenomena in traditional terminal and faster terminal SMC designs; meanwhile, the proposed NFTSMC fault-tolerant scheme also possesses the benefit of faster state convergence speed of NFTSMC. Finally, the proposed analytical results are also applied to the attitude control of a spacecraft. Simulation results demonstrate the benefits of the proposed schemes.

Study of Nonsingular Fast Terminal Sliding-Mode Fault-Tolerant Control

The problem of fault-tolerant dynamic surface control (DSC) for a class of uncertain nonlinear systems with actuator faults is discussed and an active fault-tolerant control (FTC) scheme is proposed. Using the DSC technique, a novel fault diagnostic algorithm is proposed, which removes the classical assumption that the time derivative of the output error should be known. Further, an accommodation scheme is proposed to compensate for both actuator time-varying gain and bias faults, and avoids the controller singularity. In addition, the proposed controller guarantees that all signals of the closed-loop system are semiglobally uniformly ultimately bounded, and converge to a small neighborhood of the origin. Finally, the effectiveness of the proposed FTC approach is demonstrated on a simulated aircraft longitudinal dynamics example.

Adaptive Fuzzy Observer-Based Active Fault-Tolerant Dynamic Surface Control for a Class of Nonlinear Systems With Actuator Faults

This paper studies the distributed consensus problem of multiagent systems (MASs) in the presence of nonidentical unknown nonlinear dynamics and undetectable actuation failures. Of particular interest is the development of a robust adaptive fault-tolerant consensus protocol capable of compensating uncertain dynamics/disturbances and time-varying yet unpredictable actuation failures simultaneously. By introducing the virtual parameter estimation error into the artfully chosen Lyapunov function, the consensus problem is solved with a robust adaptive fault-tolerant control scheme based upon local (neighboring) agent state information. It is shown that the proposed method is user friendly in that there is no need for detail dynamic information of the agent or costly detection/diagnosis of the actuation faults in control design and implementation, resulting in a structurally simple and computationally inexpensive solution for the leaderless consensus problem of MAS. Simulation results illustrate and verify the benefits and effectiveness of the proposed scheme.

Robust Adaptive Fault-Tolerant Control of Multiagent Systems With Uncertain Nonidentical Dynamics and Undetectable Actuation Failures

This paper presents a decentralized adaptive fuzzy approximation design to achieve attitude tracking control for formation flying in the presence of external disturbances and actuator faults. A nonsingular fast terminal sliding mode controller that is based on consensus theory is designed for distributed cooperative attitude synchronization. It solves synchronization issues between multiple satellites by information topology. In the proposed control scheme, a fuzzy logic system (FLS) is introduced to approximate unknown individual satellite attitude dynamics due to actuator faults. In order to achieve fault management without the involvement of ground-station operators, the proposed control laws do not require an explicit fault detection and isolation mechanism. Numerical simulation results including actuator dynamics and initial condition uncertainties show that the proposed strategy with FLS can compensate for a fault. The system continues to operate after wheel faults, and the closed-loop distributed tracking control system is stochastically stable.

Decentralized Fault-Tolerant Control for Satellite Attitude Synchronization

We present a satellite attitude control system design using low-cost hardware and software for a 1U CubeSat. The attitude control system architecture is a crucial subsystemfor any satellite mission since precise pointing is often required to meet mission objectives. The accuracy and precision requirements are even more challenging for small satellites where limited volume, mass, and power are available for the attitude control system hardware. In this proposed embedded attitude control system design for a 1U CubeSat, pointing is obtained through a two-stage approach involving coarse and fine control modes. Fine control is achieved through the use of three reaction wheels or three magnetorquers and one reaction wheel along the pitch axis. Significant design work has been conducted to realize the proposed architecture. In this paper, we present an overview of the embedded attitude control system design; the verification results fromnumerical simulation studies to demonstrate the performance of a CubeSat-class nanosatellite; and a series of air-bearing verification tests on nanosatellite attitude control systemhardware that compares the performance of the proposed nonlinear controller with a proportional-integral-derivative controller.

https://downloads.hindawi.com/journals/jcse/2013/657182.pdf

Design of attitude control systems for cubesat-class nanosatellite

It is necessary for precise satellite formations to keep each satellite in accurate relative attitude synchronization and to maintain relative angular velocity synchronization. An adaptive fuzzy terminal sliding mode control is proposed for a formation flying tracking system which includes acquisition, tracking, and pointing. The relative attitude of the leader and follower spacecraft under gravity gradient torque and external periodic disturbances is controlled by four reaction wheels. First, a terminal sliding mode controller is used to obtain stable and fast tracking. Then, the adaptive fuzzy logic system is used to approximate and learn the system uncertainty with the online fault and time-varied external disturbances. The system is proved to be stable, and the parameters are proved to be bounded under the control scheme, using a Lyapunov methodology. Finally, simulation results (under actuator faults like wheel failure and wheel degradation) show that the proposed control method has the advantages of...

Fault Tolerant Attitude Synchronization Control during Formation Flying

Design of Asymptotic Second-Order Sliding Mode Control for Satellite Formation Flying

This paper presents the development of low-cost methodologies to determine the attitude of a small, CubeSat-class satellite and a microrover relative to the sun's direction. The use of commercial hardware and simple embedded designs has become an effective path for university programs to put experimental payloads in space for minimal cost, and the development of sensors for attitude and heading determination is often a critical part. The development of two compact and efficient but simple coarse sun sensor methodologies is presented in this research. A direct measurement of the solar angle uses a photodiode array sensor and slit mask. Another estimation of the solar angle uses current measurements from orthogonal arrays of solar cells. The two methodologies are tested and compared on ground hardware. Testing results show that coarse sun sensing is efficient even with minimal processing and complexity of design for satellite attitude determination systems and rover navigation systems.

https://downloads.hindawi.com/journals/ijae/2013/549080.pdf

Junquan Li

Papers

Decentralized Fault-Tolerant Control for Satellite Attitude Synchronization

Design of attitude control systems for cubesat-class nanosatellite

Fault Tolerant Attitude Synchronization Control during Formation Flying

Design of Asymptotic Second-Order Sliding Mode Control for Satellite Formation Flying

A Low-Cost Photodiode Sun Sensor for CubeSat and Planetary Microrover