Yongzhao Hua

Distributed Time-Varying Formation Robust Tracking for General Linear Multiagent Systems With Parameter Uncertainties and External Disturbances

This paper investigates the time-varying formation robust tracking problems for high-order linear multiagent systems with a leader of unknown control input in the presence of heterogeneous parameter uncertainties and external disturbances. The followers need to accomplish an expected time-varying formation in the state space and track the state trajectory produced by the leader simultaneously. First, a time-varying formation robust tracking protocol with a totally distributed form is proposed utilizing the neighborhood state information. With the adaptive updating mechanism, neither any global knowledge about the communication topology nor the upper bounds of the parameter uncertainties, external disturbances and leader’s unknown input are required in the proposed protocol. Then, in order to determine the control parameters, an algorithm with four steps is presented, where feasible conditions for the followers to accomplish the expected time-varying formation tracking are provided. Furthermore, based on the Lyapunov-like analysis theory, it is proved that the formation tracking error can converge to zero asymptotically. Finally, the effectiveness of the theoretical results is verified by simulation examples.

Distributed fault-tolerant time-varying formation control for high-order linear multi-agent systems with actuator failures

This paper investigates the fault-tolerant time-varying formation control problems for high-order linear multi-agent systems in the presence of actuator failures. Firstly, a fully distributed formation control protocol is presented to compensate for the influences of both bias fault and loss of effectiveness fault. Using the adaptive online updating strategies, no global knowledge about the communication topology is required and the bounds of actuator failures can be unknown. Then an algorithm is proposed to determine the control parameters of the fault-tolerant formation protocol, where the time-varying formation feasible conditions and an approach to expand the feasible formation set are given. Furthermore, the stability of the proposed algorithm is proven based on the Lyapunov-like theory. Finally, two simulation examples are given to demonstrate the effectiveness of the theoretical results.

Fault-tolerant time-varying formation control for second-order multi-agent systems with directed topologies

This paper studies the fault-tolerant time-varying formation control problems for second-order multi-agent systems with directed topologies. Both bias and loss of effectiveness fault modes are considered. Firstly, a totally distributed fault-tolerant formation control protocol is presented using the adaptive updating gain. The proposed protocol is independent of any global information about the interaction topologies or the bounds of the actuator failures. Then the formation feasible condition is given, and it is proven that the desired formation can be achieved by the multi-agent system based on the Lyapunov stability theory. Finally, a simulation example is provided to demonstrate the effectiveness of the theoretical results.

Distributed Fault-Tolerant Time-Varying Formation Control for Second-Order Multi-Agent Systems With Actuator Failures and Directed Topologies

This brief investigates the distributed fault-tolerant time-varying formation control problems for second-order multi-agent systems with directed interaction topologies in the presence of both bias and loss of effectiveness actuator failures. Using the adaptive updating mechanism and the boundary layer theory, a continuous fault-tolerant formation control protocol is constructed to compensate for the actuator failures and the derivative of the time-varying formations. The proposed protocol is totally distributed without requiring any global knowledge about the interaction topologies or the bounds of the actuator failures. The formation feasible condition is provided, and it is proved that the formation errors are uniformly bounded and can converge to an adjustable small neighborhood of zero by the proposed continuous protocol under the influences of actuator failures.

Fault diagnosability qualitative analysis of spacecraft based on temporal fault signature matrix

Fault diagnosability analysis is an important foundation for spacecraft fault diagnosis. Combining signed directed graphs (SDG) with fault temporal information, an improved diagnosability evaluation model, temporal fault signature matrix (TFSM), is proposed in this paper. Multiple-valued evaluation of measuring variables is used in the signature matrix to represent different symptoms and time sequences of several typical faults, which is helpful to distinguish certain faults. Finally, the method is applied to fault diagnosability analysis of spacecraft propulsion system, and the simulation results verify the validity and superiority of the proposed evaluation model.

A data driven method for quantitative fault diagnosability evaluation

Knowledge of achievable diagnosability performance can provide theoretical guidance for developing diagnostic algorithms and optimizing sensor placement. A data driven approach for fault diagnosability quantitative evaluation without designing any diagnosis algorithm is proposed. Fault diagnosability is converted to similarity measure of output information which is denoted by fuzzy sets under different fault states. A quantitative evaluation measure and a specific diagnosability evaluation process are given. Finally, an example is presented to demonstrate the effectiveness of the proposed methodology.