Browsing by Author "Baradat, Cédric"
Now showing 1 - 19 of 19
Results Per Page
Sort Options
Item An agile manufacturing system for large workspace applications(Springer Verlag, 2013) Yang, Hai; Baradat, Cédric; Krut, Sébastien; Pierrot, François; MEDIOS DE PRODUCCIÓN Y ROBOTICA; Tecnalia Research & InnovationREMORA aims at offering an agile robotic solution for manufacturing tasks done on very large parts (e.g.: very long and slender parts found in aeronautic industries). For such tasks, classical machine-tools are designed at several tens of meters. Both their construction and operation require huge infrastructure supports. REMORA is a novel lightweight concept and flexible robotic solution that combines the ability of walking and manufacturing. The robot is a mobile manufacturing system which can effectuate operations with good payload capacity and good precisions for large workspace applications. This new concept combines parallel kinematics to ensure high stiffness but low inertia, and mobile robotics to operate in very large workspaces. This results in a machining center of new generation: 1. Agile manufacturing system for large workspace applications; 2. Heavy load and good precisions; 3. 5-axis machining and 5-axis locomotion/clamping; 4. Self-reconfigurable for specific tasks (workspace and force); 5. Flexible and multifunctional (machining, fixture).Item An agile manufacturing system for large workspace applications(2016-07-01) Yang, Hai; Baradat, Cédric; Krut, Sébastien; Pierrot, François; MEDIOS DE PRODUCCIÓN Y ROBOTICA; Tecnalia Research & InnovationREMORA aims at offering an agile robotic solution for manufacturing tasks done on very large parts (e.g., very long and slender parts found in aeronautic industries). For such tasks, classical machine tools are designed at several tens of meters. Both their construction and operation require huge infrastructure supports. REMORA is a novel lightweight concept and flexible robotic solution that combines the ability of walking and manufacturing. The robot is a mobile manufacturing system which can effectuate operations with good payload capacity and good precisions for large workspace applications. This new concept combines parallel kinematics to ensure high stiffness but low inertia and mobile robotics to operate in very large workspaces. This results in a machining center of new generation: (1) agile manufacturing system for large workspace applications, (2) heavy load and good precisions, (3) 5-axis machining and 5-axis locomotion/clamping, (4) self-reconfigurable for specific tasks (workspace and force), and (5) flexible and multifunctional.Item AIR2, un robot parallèle à actionnement pneumatique à deux degrés de liberté pour les applications de prise et dépose d'objets(2011) Chikh, Lotfi; Baradat, Cédric; Poignet, Philippe; Pierrot, François; Michelin, Micaël; Tecnalia Research & InnovationA two degrees-of-freedom pneumatically driven parallel robot has been developed for pick-and-place of payloads comprised between 5 and 20 kg using standard double acting cylinders cheaper than electrical motors. After the general presentation of the robot, the actuator models are developed and a novel control strategy is introduced based on a cascade scheme with a predictive position controller and an inner H∞ force control. Some experimental results are then presented and analyzed in order to show the effectiveness of the controllers.Item A combined GPC-H ∞ cascade control for pneumatic actuators: A comparative study(2012) Chikh, Lotfi; Poignet, Philippe; Pierrot, François; Baradat, Cédric; Michelin, Micaël; Tecnalia Research & InnovationThis paper presents a comparison study between three types of pneumatic actuators. The goal is to choose the most suitable for low cost and high power-to-weight pick-and-place parallel robotic tasks. A cascade strategy scheme with an outer predictive position controller and an inner pressure H ∞ controller is developed and adapted for both cylinders and PAMs. Experimentations show that the cascade scheme presents better results than state of the art sliding mode control: the predictive controller reduces the time response and guarantees good dynamic tracking while the H ∞ inner pressure controller provides more robustness relatively to load variations which are important requirements for pick-and place robotic tasks.Item Effects of non-negligible cable mass on the static behavior of large workspace cable-driven parallel mechanisms(2009) Riehl, Nicolas; Gouttefarde, Marc; Krut, Sébastien; Baradat, Cédric; Pierrot, François; Tecnalia Research & InnovationCable-driven robots are currently extensively studied. Generally, for this type of manipulators, cables are considered to be massless and inextensible. But for large working volume applications, their mass cannot be neglected. Based on a well-known model which describes the profile of a cable under the action of its own weight, the inverse and forward kinematics of minimally constrained cable-driven manipulators can be numerically computed. This paper studies the effects of taking cable mass into account by comparison to classical massless cable model. It highlights the real effects of such a model on cable lengths to reach a given position. The effects on cable tensions are also studied.Item Fusion reactor handling operations with cable-driven parallel robots(2015-10-01) Izard, Jean Baptiste; Michelin, Micael; Baradat, Cédric; Tecnalia Research & InnovationCable-driven parallel robots (CDPR) are in their concept cranes with inclined cables which allow control of all the degrees of freedom of its payload, and therefore stability of all the degrees of freedom, including rotations. The workspace of a CDPR is only limited by the length of the cables, and the payload capacity related to the mass of the whole robot is very important. Besides, the control being based on kinematic models, the behavior of a CDPR is really that of a robot capable of automated trajectories or remote handling. The present paper gives a presentation of two use case studies based on some of the assembly phases and remote handling actions as designed for the recent fusion machines. Based on the use cases already in place in fusion reactor baselines, the opportunity of using CDPR for assembly of structural elements and coils is discussed. Finally, prospects for remote handling equipment from the reactor in hot cells are envisioned based on current CDPR research.Item Geometry Selection of a Redundantly Actuated Cable-Suspended Parallel Robot(2015-04-01) Gouttefarde, Marc; Collard, Jean François; Riehl, Nicolas; Baradat, Cédric; Tecnalia Research & InnovationThis paper is dedicated to the geometry selection of a redundantly actuated cable-suspended parallel robot intended to manipulate heavy payloads over a wide workspace. Cable-suspended refers here to cable-driven parallel robots in a crane-like setting, where all the cable drawing points are located on top of the base frame, gravity being used to keep the cables taut. Geometry selection consists of determining the relative positions of the cable drawing points on the base frame and of the cable attachment points on the mobile platform together with the cable arrangement between these two sets of points. An original performance index is introduced. It is defined as the maximum acceptable distance between the mobile platform geometric center and the center of mass of the set consisting of the platform and a payload. This performance index is of particular interest in heavy payload handling applications. Used within a two-phase geometry selection strategy, it yields a new cable-suspended robot geometry having a very large workspace to footprint ratio and able to handle heavy payloads. A large-dimension redundantly actuated cable-suspended robot was built in order to demonstrate these capabilities.Item Integrating structural and input design of a 2-DOF high-speed parallel manipulator: A flexible model-based approach(2010-11) Da Silva, Maíra M.; De Oliveira, Leopoldo P.R.; Brüls, Olivier; Michelin, Micaël; Baradat, Cédric; Tempier, Olivier; De Caigny, Jan; Swevers, Jan; Desmet, Wim; Van Brussel, Hendrik; Tecnalia Research & InnovationThis paper discusses the integrated design of parallel manipulators, which exhibit varying dynamics. This characteristic affects the machine stability and performance. The design methodology consists of four main steps: (i) the system modeling using flexible multibody technique, (ii) the synthesis of reduced-order models suitable for control design, (iii) the systematic flexible model-based input signal design, and (iv) the evaluation of some possible machine designs. The novelty in this methodology is to take structural flexibilities into consideration during the input signal design; therefore, enhancing the standard design process which mainly considers rigid bodies dynamics. The potential of the proposed strategy is exploited for the design evaluation of a two degree-of-freedom high-speed parallel manipulator. The results are experimentally validated.Item Locomotion approach of REMORA: A reonfigurable mobile robot for manufacturing Applications(2011) Yang, Hai; Krut, Sébastien; Baradat, Cédric; Pierrot, François; MEDIOS DE PRODUCCIÓN Y ROBOTICA; Tecnalia Research & InnovationThis paper presents the locomotion approach of a novel quadruped robot which is able to carry various effectors for achieving manufacturing tasks in large workspaces. Equipped with lockers on some of the passive joints and clamping devices at the end of its limbs, this quadruped uses eight actuators for achieving manufacturing tasks as well as locomotion tasks. In the following sections, we first present the proposed robot and its two working modes. Then, the locking strategy of the robot is formulated as an optimization problem. Also, a practical method for managing the limbs swinging movement is addressed. At last, the presented approach is applied on two concrete examples. Possessing a low degree of kinematic redundancy, the proposed quadruped shows a reasonable locomotion capacity which allows it to achieve locomotion with respect to some extra constrains in its workspaces.Item A mixed GPC-H∞ robust cascade position-pressure control strategy for electropneumatic cylinders(2010) Chikh, Lotfi; Poignet, Philippe; Pierrot, François; Baradat, Cédric; Tecnalia Research & InnovationA robust cascade strategy combining an outer position predictive control loop and an inner H∞ pressure control loop is proposed and tested on an electropneumatic testbed for parallel robotic applications. Two types of cylinders are tested, the standard double acting cylinder and the rodless one. A position/pressure difference (or force) strategy is developed and implemented. As the behavior of the nonlinear cylinders is nonlinear, a feedback linearization strategy is adopted. A Generalized Predictive Controller (GPC) is synthesized for the position outer loop and a constrained LMI based H∞ controller is synthesized for the pressure inner loop. Experimental results show the feasibility of the control strategies and good performances in terms of robustness and dynamic tracking.Item A new concept of self-reconfigurable mobile machining centers(2010) Yang, Hai; Krut, Sébastien; Baradat, Cédric; Pierrot, François; MEDIOS DE PRODUCCIÓN Y ROBOTICA; Tecnalia Research & InnovationIn this paper, several considerations for designing industry oriented robots which combine the mobility of legged robots and advantages of parallel mechanisms are outlined. A tripod and a quadruped with the same kind of legs are studied. The robots' kinematic models are built for achieving the machining and walking scenarios. The simulations show that: integrating some clamping devices and some lockable passive joints, six actuators are enough to build a legged manipulator which can not only perform 6-axis machining but can also walk on a curved supporting media. Using the "modified condition number" index, the two mechanisms are compared. They have similar workspaces and static wrench performances during the machining phase. During walking processes, however, their behaviors are different, and each of them shows interesting features depending on application requirement.Item A novel 4 DoFs (3T-1R) parallel manipulator with actuation redundancy – Workspace analysis(Kluwer Academic Publishers, 2014) Shayya, Samah; Krut, Sébastien; Company, Olivier; Baradat, Cédric; Pierrot, François; Petuya, Victor; Pinto, Charles; Petuya, Victor; Lovasz, Erwin-Christian; Lovasz, Erwin-Christian; Pinto, Charles; Tecnalia Research & Innovationpaper presents a novel 4 dofs (3T-1R1) parallel actuatedly redundant mechanism and its workspace analysis, based on a performance index involving velocity and force capabilities. The robot is capable of performing a half-turn2 about the z axis. Moreover, having all of its prismatic actuators along one direction; the x motion is independent- only limited by the stroke of the prismatic actuators. The mechanism is characterized by elevated dynamical capabilities having its actuators at base.Item On the design of mobile parallel robots for large workspace applications(2011) Yang, Hai; Krut, Sébastien; Pierrot, François; Baradat, Cédric; MEDIOS DE PRODUCCIÓN Y ROBOTICA; Tecnalia Research & InnovationIn this paper, several considerations for designing industry oriented robots which combine the mobility of legged robots and advantages of parallel mechanisms are outlined. For designing such optimized robots in terms of simplicity and performance, a topology study is done based on the mobility analysis. Applying some design constraints, potential topologies of such robots are identified. One architecture is chosen for designing a tripod robot. Both inverse and forward kinematic problems of this robot are derived in order to simulate its gait motion. The analysis and simulations show that: integrating some clamping devices and some lockable passive joints, six actuators are enough to build a legged manipulator which can not only perform 6-axis machining but can also walk on a curved supporting media.Item On the determination of cable characteristics for large dimension cable-driven parallel mechanisms(2010) Riehl, Nicolas; Gouttefarde, Marc; Baradat, Cédric; Pierrot, François; Tecnalia Research & InnovationGenerally, the cables of a parallel cable-driven robot are considered to be massless and inextensible. These two characteristics cannot be neglected anymore for large dimension mechanisms in order to obtain good positioning accuracy. A well-known model which describes the profile of a cable under the action of its own weight allows us to take mass and elasticity into account. When designing a robot, and choosing actuator and cable characteristics, a calculation of maximal tension has to be done. However, because cable mass has a significant effect on cable tensions, a model including cable mass has to be included in the design step. This paper proposes two methods to determine the appropriate cable and hence the maximal tensions in the cables. Applied to a large dimension robot, taking cable mass into account is proved to be necessary in comparison with an equivalent method based on the massless cable modeling. In this paper, only moving platform static equilibria are considered (slow enough motions).Item On the performance evaluation and analysis of general robots with mixed dofs(Institute of Electrical and Electronics Engineers Inc., 2014-10-31) Shayya, Samah; Krut, Sébastien; Company, Olivier; Baradat, Cédric; Pierrot, François; Tecnalia Research & InnovationThis paper deals with the kinetostatic performance evaluation regarding translational and rotational motions of general robots with mixed operational degrees of freedom (dofs). Also, robots with different types of actuators can be analyzed based on the same approach without any problem. Besides, the generality of the approach embraces serial, parallel, actuatedly or kinematically redundant robots. The paper seeks clarifying the issue and providing a relevant solution. It also clarifies some other useful points in this matter.Item On the static workspace of large dimension cable-suspended robots with non negligible cable mass(2010) Riehl, Nicolas; Gouttefarde, Marc; Pierrot, François; Baradat, Cédric; Tecnalia Research & InnovationIn most studies on parallel cable-driven robots, cables are supposed to be massless and inextensible. However, in the case of large dimension robots, cable mass and elasticity cannot be neglected anymore. Based on a well-known cable static model which takes these characteristics into account, the formulation of the inverse kinematics of n cable/n-DOF cable-driven robots is presented. The consequences of this modeling on the usual static workspace definition is then discussed. Notably, as the tension in a cable is not constant, the maximal tension along the cable has to be found. An example of a planar 3 cable/3-DOF robot is used to highlight that, in some particular poses, the mobile platform can be in static equilibrium while some cables are hanging below the platform. Finally, new limiting factors for the definition of the static workspace are introduced and applied to the same planar robot example which shows the significance of taking into account cable mass and elasticity.Item Par2: A spatial mechanism for fast planar two-degree-of-freedom pick-and-place applications(2011-02) Company, Olivier; Pierrot, François; Krut, Sébastien; Baradat, Cédric; Nabat, Vincent; Tecnalia Research & InnovationThis paper introduces a new two-degree-of-freedom (dof) parallel manipulator producing two translations in the vertical plane. One drawback of existing robots built to realize these dof is their lack of transversal stiffness, 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 parallel architecture is a spatial mechanism which guarantees a good transversal stiffness. It 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 two passive chains which are coupled to create 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 400 ms-1 can be achieved while keeping a low tracking error.Item Simplified static analysis of large-dimension parallel cable-driven robots(Institute of Electrical and Electronics Engineers Inc., 2012) Gouttefarde, Marc; Collard, Jean François; Riehl, Nicolas; Baradat, Cédric; Tecnalia Research & InnovationThis paper introduces a new simplified static analysis of parallel robots driven by inextensible cables of non-negligible mass. It is based on a known hefty cable static modeling which seems to have been overlooked in previous works on parallel cable-driven robots. This cable modeling is obtained from a well-known sagging cable modeling, known as the catenary, by assuming that cable sag is relatively small. The use of the catenary has been shown to lead to a non-linear set of equations describing the kinetostatic behavior of parallel robots driven by cables of non-negligible mass. On the contrary, the proposed simplified static analysis yields a linear relationship between (components of) the forces in the cables and the external wrench applied to the robot mobile platform. As a consequence, by means of the simplified static analysis, useful wrench-based analysis and design techniques devised for parallel robots driven by massless cables can now be extended to cases in which cable mass is to be accounted for.Item Simulation and control with XDE and Matlab/Simulink of a cable-driven parallel robot (CoGiRo)(Kluwer Academic Publishers, 2015) Michelin, Micaël; Baradat, Cédric; Nguyen, Dinh Quan; Gouttefarde, Marc; Pott, Andreas; Bruckmann, Tobias; Tecnalia Research & InnovationWe present in this paper the process allowing to create a cable-driven parallel robot (CDPR) simulation within the XDE software environment in C++ language. The elementary classes constituting a CDPR are shown with their constructor specificities. The winches, the pulleys, the cable fastenings and the platform are presented. The parameterization of elements such as the cable material characteristics, structure and size are detailed. An interface between the XDE cable-driven parallel robot simulator and a Matlab/Simulink controller have been developed. Inputs and outputs are exchanged between the controller and the simulated cable-driven robot, exactly as it is done with a physical robot.