Browsing by Author "Chikh, L."
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Item Multivariable L1 Adaptive Depth and Attitude Control of MEROS Underwater Robot With Real-Time Experiments(Elsevier B.V., 2022-10-01) Chikh, L.; Chemori, A.; Wang, S.; Rincon-Ardilla, Liz; Tecnalia Research & InnovationThis paper deals with L1 adaptive control of a novel omnidirectional underwater vehicle called MEROS. To the best of our knowledge, this is the first study of depth and attitude (i.e. φ, θ, and ψ) tracking control on an underwater vehicle. We experimentally prove the effectiveness of the proposed control approach by commanding in closed-loop simultaneously the four aforementioned degrees of freedom (DoFs). The dynamic model of MEROS is highly nonlinear with coupling effects between the different DoFs making its stabilization and tracking control more challenging than conventional ROVs (remotely operated vehicles). Therefore, the use of a robust controller becomes essential, and the proposed scheme allows to ensure robustness whilst fast adaptation is achieved. Real-time experiments are performed to show the effectiveness of the proposed control design.Item Rise feedback control of cable-driven parallel robots: Design and real-time experiments(2020) Hassan, G.; Chemori, A.; Chikh, L.; Hervé, P. E.; El Rafei, M.; Francis, C.; Pierrot, F.; Tecnalia Research & Innovation; ROBOTICA_AUTOMAControl of Cable-Driven Parallel Robots (CDPRs) is considered as a challenging task due to their highly nonlinear dynamic behavior, abundant uncertainties, low-stiff cables, parameters variation, cable tensions, and actuation redundancy. Hence, a robust controller is needed to obtain higher performance despite the above mentioned issues. In this paper, we propose a Robust Integral of the Sign of the Error (RISE) control scheme to solve the problem of reference trajectory tracking. RISE feedback control is a robust nonlinear continuous controller which can guarantee a semi-global asymptotic tracking under limited assumptions on the system's structure. RISE ensures the closed-loop system robustness towards parametric uncertainties and external disturbances. The proposed control solution is designed and implemented in real-time experiments on a fully constrained 4-DOF Cable-Driven Parallel Robot (CDPR) named PICKABLE. The obtained experimental results show that the proposed controller outperforms the classical PID controller and the first-order Sliding Mode Control (SMC) in terms of tracking performances and robustness towards payload variations.