水下航行器执行机构的故障诊断与容错控制

Fault diagnosis and fault tolerant control for actuators of underwater vehicles

为了解决水下航行器执行机构的故障,提出低依赖性和高普适性的故障诊断与容错控制算法.故障诊断由检测、隔离和辨识3个阶段组成.首先,定义比例式、偏差式和常量式3种故障类型,设计相应故障观测器,在满足指数收敛性的前提下检测出故障.其次,基于故障估计与其微分的指数收敛性,建立故障函数,以方差最小为条件隔离出实际故障;然后,联立控制输入方程和故障估计,辨识出故障执行机构.在故障诊断和反馈控制的基础上,通过修正期望控制输入,实现满足闭环稳定性的容错控制.经水下航行器回坞仿真实验验证,所提故障诊断和容错控制算法可行且有效.

In dealing with the fault problems occurred on the actuators of underwater vehicles,we propose the fault diagnosis and the fault tolerant control algorithms with low dependence and high universality.The fault diagnosis algorithm comprises the stages of detection,isolation and identification.Three types of actuator faults,namely,the proportional,the deviated and the constant faults are defined,for which the corresponding observers are designed such that the fault estimates can be detected by satisfying the exponential convergence requirement.To isolate the actual fault among the three estimates,fault functions are generated based on the exponentially converged fault estimates and the corresponding derivatives,of which the deduced data with the lowest variance are used for isolation.The actual fault actuator is successfully identified by combining the control input equation with the isolated fault estimate.Based on the fault diagnosis result and the feedback control design,the fault tolerant control （FTC） which satisfies the stabilization requirement is realized by modifying the desired control input directly.Through an underwater vehicle docking simulation,the feasibility and effectiveness of the addressed algorithms are validated.