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2018
Wälder Georg, Fulliquet Damien, Foukia Noria, Jaquenod Frédéric, Lauria Michel, Rozsnyo Roland, Lavazais B., Perez R.
Procedia CIRP, 2018, 68, pp. 109-114
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Résumé:
Wire EDM is a time consuming process which requires several, (cost significant), consumables like wire, filters or deionization resin. Based on machining history and sensor inputs a developed model, e.g. an intelligent software, allows to predict the status & future capacity of consumables and wear parts and thus avoid down-times of machine. The use of a predictive model for estimation of the lifetime of consumable and wear parts will be a significant step in the automation of (wire EDM) machines.
Clavien Lionel, Lauria Michel, Michaud François
Robotics and Autonomous Systems, 2018, 106, pp. 47-57
In order to move safely and accurately, mobile platforms using steerable wheels require adequate coordination of their actuators. One possibility to achieve actuator coordination is to control the motion of the chassis’ instantaneous centre of rotation (ICR) and motion around it. Considering the chassis as a rigid body, the ICR is located at the intersection of each wheel’s zero motion axis. In practice however, these axes may not concur, in particular when compliant actuators are used for wheel steering. They then no more define precisely an ICR and only an estimation of its position can be computed. Moreover, most parametrizations of the ICR position bring in singularities with no physical meaning, which hinder estimation. This paper introduces the H representation, a new parametrization of the motion state space free of any non-structural singularities, and presents an algorithm which estimates the ICR within the joint space. The proposed approach is compared in terms of reliability, efficiency, accuracy and robustness with three methods working within the operational space. Results suggest that the proposed estimation approach provides the best compromise for these performance indicators.
Robotics and Autonomous Systems, 2018, 106, pp. 58-68
AZIMUT-3 is a nonholonomic omnidirectional platform design using sidewards off-centred compliant wheels. This design makes it possible to experiment with the use of the chassis’ instantaneous centre of rotation (ICR) for motion control. Research on ICR-based motion controllers has focused on handling structural singularities and misses a more general consideration of the chassis’ kinematic and physical constraints like steering, velocity and acceleration constraints. This paper presents the design of an ICR-based motion controller for AZIMUT-3. Leveraging a new parametrization of the motion state space and the associated representation in R3 (collectively referred to as the H representation) and adapting a time scaling principle initially developed for manipulator trajectories, the designed motion controller is able to handle actuators coordination and their physical limits, as well as structural singularities. Results of tests done with the platform are presented, demonstrating the applicability of the proposed motion controller in efficiently handling these issues.
2015
Gobron Stéphane, Zannini Nicolas, Wenk Nicolas, Schmitt Carl, Charrotton Yannick, Fauquex Aurélien, Lauria Michel, Degache Francis, Frischknecht Rolf
Dans De Paolis, L., Mongelli, A., AVR 2015: Augmented and Virtual Reality : Lecture Notes in Computer Science (22 p.). 2015, Cham : Springer
In the health domain, the field of rehabilitation suffers from a lack specialized staff while hospital costs only increase. Worse, almost no tools are dedicated to motivate patients or help the personnel to carry out monitoring of therapeutic exercises. This paper demonstrates the high potential that can bring the virtual reality with a platform of serious games for the rehabilitation of the legs involving a head-mounted display and haptic robot devices. We first introduce SG principles, nowadays rehabilitation context, and an original applied haptic device called Lambda Health System. The architecture of the model is then detailed, including communication specifications showing that lag is imperceptible for user. Finally, to improve this prototype, four serious games for rehabilitation using haptic robots and/or HMD were tested by 33 health specialists.
2014
Frémy Julien, Ferland François, Lauria Michel, Michaud François
Robotics and Autonomous Systems, 2014, vol. 2, no. 4, pp. 579-590
Physical guidance is a natural interaction capability that would be beneficial for mobile robots. However, placing force sensors at specific locations on the robot limits where physical interaction can occur. This paper presents an approach that uses torque data from four compliant steerable wheels of an omnidirectional non-holonomic mobile platform, to respond to physical commands given by a human. The use of backdrivable and torque-controlled elastic actuators for active steering of this platform intrinsically provides the capability of perceiving applied forces directly from its locomotion mechanism. In this paper, we integrate this capability into a control architecture that allows users to force-guide the platform with shared-control ability, i.e., having the platform being guided by the user while avoiding obstacles and collisions. Results using a real platform demonstrate that user’s intent can be estimated from the compliant steerable wheels, and used to guide the platform while taking nearby obstacles into consideration.
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