Browsing by Author "Pierrot, F."
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Item Above 40g acceleration for pick-and-place with a new 2-dof PKM(2009) Pierrot, F.; Baradat, C.; Nabat, V.; Company, O.; Krut, S.; Gouttefarde, M.; Tecnalia Research & InnovationThis paper introduces a new two-degree-offreedom parallel manipulator producing two translations in the vertical plane. One drawback of existing robots built to realize those dof is their lack of rigidity along the transversal axis, another one being their limited ability to provide very high acceleration. Indeed, these architectures cannot be lightweight and stiff at the same time. The proposed architecture is a spatial mechanism which guarantees a good stiffness along the transversal axis. This parallel architecture is composed by two actuated kinematic chains, and two passive chains built in the transversal plane. The key feature of this robot comes from the passive chains which are coupled for creating a kinematic constraint: the platform stays in one plane. A stiffness analysis shows that the robot can be lighter and stiffer than a classical 2 dof mechanism. A prototype of this robot is presented and preliminary tests show that accelerations above 40 g can beachieved while keeping a low trackingerror.Item On the design of a fast parallel robot based on its dynamic model(2008) Nabat, V.; Krut, S.; Company, O.; Poignet, P.; Pierrot, F.; Khatib, Oussama; Kumar, Vijay; Rus, Daniela; Tecnalia Research & InnovationA high-speed, four-degree-of-freedom (dof), parallel robot is analysed by considering in detail its dynamic model as well as issues directly linked to its practical design. A small change in its kinematics is then proposed that lead to a dramatic change in its dynamic behaviour, providing room for a radical improvement and a new version of the robot.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.