Under-actuated autonomous underwater vehicle actuator fault robust fault-tolerant control method

Abstract

The invention discloses an under-actuated AUV actuator fault robust fault-tolerant control method. The method includes the following steps that a position error vector of motions of an AUV is defined;a new error vector is defined; a neural network method is used for approaching a composite uncertain item; an auxiliary dynamic system is designed; an under-actuated AUV actuator fault robust fault-tolerant control law is designed. According to the method, the dynamic uncertainty and disturbance uncertainty of the AUV are approximated by applying a neural network, and prior knowledge of dynamic parameters and ocean current disturbance of a motion mathematical model of the AUV is not needed, so that the method has good self-adaptive capability and robustness. According to the method, the influence of actuator faults on an AUV control system is treated by designing an auxiliary dynamic system, and the reliability of an AUV motion control system is improved. Coordinate transformation is introduced to define an output vector of the AUV, the problem of under-actuation of the AUV is solved, under-actuated AUV three-dimensional motion control is realized, and the method better conforms to reality.

Description

technical field [0001] The invention relates to the field of marine engineering equipment, in particular to a fault-robust fault-tolerant control method for actuators of underactuated underwater robots. Background technique [0002] Autonomous underwater vehicles (AUVs), as a tool for human exploration and development of the ocean, play an important role in ocean operations. The AUV system itself has the characteristics of underactuation, dynamic uncertainty, etc., and will be disturbed by ocean currents during navigation; on the other hand, the actuators of AUVs are always exposed to seawater during operation, and will be aged and damaged due to seawater erosion and other reasons. thus malfunctioning. Once the actuator fails, the AUV not only cannot continue to complete the task, but also cannot be recovered, resulting in huge losses. Therefore, it is particularly important to study the robust and fault-tolerant control of actuator faults in underactuated AUVs to improve ...

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Problems solved by technology

However, none of the above patents take into account the underactuated nature of underwater vehicles and the possible failure of actuators

[0004] Chinese patent CN107463097A discloses an adaptive quantitative fault-tolerant control method for underwater robots. Based on CN108170151A, the method considers the partial failure of the actuator, and uses adaptive technology to estimate the upper bound of the actuator efficiency factor describing the fault situation. Design a fault-tolerant controller for underwater vehicles; however, this patent also does not consider the underactuated characteristics of underwater vehicles

However, this patent only deals with the failure of the vertical rudder, and the designed control system cannot realize the three-dimensional movement of the underwater robot

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