Autonomous underwater inspection robot under disturbances

Autonomous underwater inspection robots are getting worldwide interest since they used for various applications like surveying seabed mosaics, shipwreck search, pipeline inspection etc. For performing the above applications, the control of position and altitude of underwater inspection robots are extremely significant as the worth of information obtained is very much reliant in the correctness of position control and tracking of the Autonomous underwater inspection robot. So a Time Delay Controller for the position and altitude control of an underwater inspection robot with disturbances is introduced. A TDC performs its best when the data acquisition rate is rapid. But for the control of underwater inspection robot, which uses a Doppler velocity log navigation system (DVL) as sensor, it can't maintain the data acquisition rate fast since DVL gives data at a poor acquisition rate, results in lessening the performance of TDC. So an integral sliding-mode controller is also provided to the typical TDC to avoid this problem and to improve the control precision even if the DVL navigation system is in operation. The controller proposed here makes computations easier and it reduces the steady state error.