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Sliding mode control, due to its robustness against modelling imprecisions and external disturbances, has been successfully employed to the dynamic positioning of remotely operated underwater vehicles. In order to improve the performance of the complete system, the discontinuity in the control law must be smoothed out to avoid the undesirable chattering(More)
The HippoCampus platform is a low-cost micro autonomous underwater vehicle for swarm robotics research. This paper presents the hardware and software design, the communication link, instrumentation, and control system. The quadrotor design enables the vehicle to perform agile maneuvers in a very confined test tank. Vehicle navigation is based on the(More)
The dynamic behavior of underwater robotic vehicles can be greatly influenced by the nonlinear dynamics of the vehicle thrusters. In this way, the implementation of a good control strategy for the thruster subsystem is essential for the accurate control of the entire robotic vehicle. It was already shown in the literature that without compensation for(More)
Sliding mode control is a very attractive control scheme because of its robustness against modelling imperfections and external disturbances. It has been successfully employed to the dynamic positioning of remotely operated underwater vehicles. In such situations, the discontinuities in the control law must be smoothed out to avoid the undesirable(More)
In order to apply the sliding mode control to a remotely operated vehicle (ROV), prior knowledge of exact bounds for parameter uncertainties and external disturbances is a prerequisite. However, these bounds may not be easily obtained because of the complexity and unpredictability of the structure of uncertainties in the dynamics of ROVs. In order to(More)
In this work an algorithm for on-line estimation of the nonlinear hydro-dynamics in underwater vehicles is presented. The algorithm is able to estimate physical parameters from natural operation signals. Identifiability and convergence of the parameter trajectories are analyzed. The application of the algorithm to a spherical vehicle is described with(More)