hardware in the loop

Implementing control and guidance systems on an autonomous underwater vehicle requires spending much money, which in case of failure, will suffer heavy losses. For this purpose, the complete method of evaluating an autonomous underwater vehicle's guidance, control, and navigation system is the hardware in the loop test before the diving and buoyancy so that the validation of the designed system can be evaluated in conditions close to reality.This research discusses the implementation of the hardware in the loop test to guide the path of a remotely operated vehicle. Considering the dynamics of the underwater robot - which is highly non-linear and dependent; First, the design of a free model sliding mode controller in the presence of underwater currents as a disturbance in the form of software in the loop is discussed. Second, the software in the loop test is performed by applying the control signal obtained from the proposed controller to the driver of the electric motor as the robot's proportion, whose mathematical model has been identified in the laboratory. Finally, by gradually replacing the hardware drives of the robot in the loop, the hardware in loop test of six degrees of freedom of the remotely operated vehicle is done in real-time in the presence of environmental disturbances. The proximity of the hardware in the loop test results with the software test in the loop shows the correctness of the work done. Meanwhile, the performance of the proposed controller is compared with the PID controller in trajectory tracking. In the end, the accuracy and validity of the implemented hardware table are examined by analyzing the frequency spectrum of the measurements of the hardware in the loop rig.

A robust controller for an uncrewed underwater vehicle operating in complex oceanic environments is essential because external disturbances from the environment uncertainty in the model potentially disrupt the system's stability. This research proposes a Supper-Twisting Sliding mode controller for an uncrewed underwater vehicle in the presence of external disturbances, limitations of thrusters, and measurement noise. Supper-Twisting is a second-order sliding-mode controller that combines a continuous signal with a discrete signal to produce a robust controller. The stability of the proposed controller is investigated using the phase plane graphical method. A linear Kalman filter is used to estimate the measurement error in the navigation system and then correct them.The performance of the controller and the proposed estimation algorithm in the motion control loop of the underwater robot are compared with other controllers. In addition, the validation of the proposed methods is evaluated in the form of hardware in the loop with the presence of electric motors as robot propulsions in the MATLAB®/ Simulink® Real-Time environment.