Browsing by Author "Tarbouriech, Sophie"
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Item Anti-windup design for saturation management during piezo-actuated vibration attenuation of the high-speed parallel robot Par2(IFAC Secretariat, 2013) Douat, Luiz R.; Queinnec, Isabelle; Garcia, Germain; Michelin, Micaël; Pierrot, François; Tarbouriech, Sophie; Tecnalia Research & InnovationThe two degrees of freedom parallel robot Par2 is designed for high-speed and high-accuracy industrial pick-and-place operation tasks. As a result of high acceleration trajectories, its end-effector undergoes some undesirable vibrations after reaching the stop position, compromising precision and leading to an increase in the operation cycle time. Accelerometer sensors placed on the end-effector and piezoelectric patch actuators wrapped around the robot arms are employed in order to actively reduce these vibrations. Without taking into account saturation limitations, a robust controller is designed, minimizing vibrations for the robot nominal operating point but failing for some extreme operating points, due to high control efforts. An anti-windup strategy is then employed to deal with the saturation of the actuator. Such a strategy presents the advantage, with respect to the strategy which would consider a controller with smoother control efforts, to maintain a good level of vibration attenuation on the whole operation domain. Simulations and experimental results attest the adequacy of the proposed solution.Item Identification and vibration attenuation for the parallel robot par2(2014-01) Douat, Luiz R.; Queinnec, Isabelle; Garcia, Germain; Michelin, Micaël; Pierrot, François; Tarbouriech, Sophie; Tecnalia Research & InnovationPar2 is a parallel robot with two degrees of freedom designed for high-speed and high-accuracy industrial pick-and-place operation tasks. As a result of the high acceleration trajectories, the end-effector undergoes some undesirable vibrations after reaching the stop positions, compromising its precision and leading to an increase in the operation cycle time. Accelerometer sensors placed on the end-effector and piezoelectric patch actuators wrapped around the robot arms are employed in order to actively reduce these vibrations in a noncollocated closed-loop setting. After submitting the robot to an identification procedure, the obtained nominal model is used to synthesize a reduced order controller with the H∞ loop-shaping technique. Performance analysis as well as simulation and experimental results show that vibration reduction is achieved around the nominal operating point, but fails for some extreme operating points, due to high control efforts. An anti-windup strategy is then employed to deal with the saturation of the actuator, which allows achieving vibration attenuation on the whole operation domain, for a given configuration of the robot at the stop point.