A Robust Fault Tolerant Control Method for Underactuated Underactuated Underwater Robot Actuator Faults

Abstract

The invention discloses a fault-robust fault-tolerant control method of an underactuated AUV actuator, which comprises the following steps: defining a position error vector of the AUV movement; defining a new error vector; using a neural network method to approach compound uncertain items; and designing an auxiliary dynamic system ; Design a fault-robust fault-tolerant control law for underactuated AUV actuators. Because the present invention uses the neural network to approximate the dynamic uncertainty and disturbance uncertainty of the AUV, it does not need the prior knowledge of the dynamic parameters of the AUV motion mathematical model and the ocean current disturbance, and has good self-adaptability and robustness. The invention handles the impact of actuator failure on the AUV control system by designing an auxiliary dynamic system, thereby improving the reliability of the AUV motion control system. The invention introduces the coordinate transformation to define the output vector of the AUV, solves the under-actuation problem of the AUV, and realizes the three-dimensional motion control of the under-actuation AUV, which is more practical.

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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