Development of Fault Accommodation System for Thrusters of Underwater Robots

This paper considers the problem of increasing the reliability of operation of underwater robots through the use of accommodation systems that compensate for the consequences of faults that appear in the thrusters. A new method for constructing accommodation systems, which contains three stages, is proposed. At the first, the detection of emerging faults is carried out using the bank of diagnostic observers. Each observer is synthesized according to a special procedure in such a way that its residual is sensitive to some group of faults and insensitive to others. This makes it possible to isolate each specific fault. At the second stage, the values of sensor errors and deviations of the parameters of the thruster from their nominal values are estimated by additional sliding mode observers. At the third stage, additional control signals for robot’s thrusters are formed. They ensure the stabilization of dynamic properties of thrusters under the faults. The results of simulation are presented, which have confirmed the operability and high efficiency of the synthesized accommodation system.