1,721,014 research outputs found
Solving signal decoupling problems through self-bounded controlled invariants
No full textThis paper deals with decoupling problems of unknown, measurable and previewed signals. First the well known solutions of unknown and measurable disturbance decoupling problems are recalled. Then new necessary and sufficient constructive conditions for the previewed signal decoupling problem are proposed. The discrete time case is considered. In this domain previewing a signal by p steps means that the k-th sample of the signal to be decoupled is known p steps in advance. The main result is to prove that the stability condition for all of the mentioned decoupling problems does not change, i.e. the resolving subspace to be stabilized is the same independently of the type of signal to be decoupled, being it completely unknown (disturbance), measured or previewed. The problem has been studied through self-bounded controlled invariants, thus minimizing the dimension of the resolving subspace which corresponds to the infimum of a lattice. Note that reduced dimension on resolving controlled invariant subspace yields to reduce the order of the controller units
La collezione entomologica Mario Pavan. Catalogo della Mostra.
No full textCatalogo della mostra sulle collezioni entomologiche del Prof. Mario Pava
Supervisory Switching Strategy in Motion/Force Control of Robotic Manipulation
No full textA switching controller for a class of robotic manipulators with grasping capabilities is presented. The aim is to control the motion of the grasped object along a
desired trajectory while complying with contact force constraints. The algorithm successfully performs its control task by switching between several controllers induced by different
operating conditions of the manipulator–object system. Simulation results are presented
to show the efficacy of the proposed method
Generalized signal decoupling problem with stability for discrete-time systems
No full textThis paper deals with the decoupling problems of unknown, measurable, and previewed signals. First, well-known solutions of unknown and measurable disturbance decoupling problems are recalled. Then, new necessary and sufficient constructive conditions for the previewed signal decoupling problem are proposed. The discrete-time case is considered. In this domain, previewing a signal by p steps means that the kth sample of the signal to be decoupled is known p steps in advance. The main result is that the stability condition for the mentioned decoupling problems does not change; i.e., the resolving subspace to be stabilized is the same independently of the type of signal to be decoupled, no matter whether it is completely unknown, measured, or previewed. The problem has been studied through self-bounded controlled invariants, thus minimizing the dimension of the resolving subspace which corresponds to the infimum of a lattice. The reduced dimension of the resolving controlled invariant subspace reduces the order of the controller units
Dynamic Local Models for Stable Multi-Contact Haptic Interaction with Deformable Objects
No full textThis paper describes a nw technique for allowing multiple users to haptically interact with a set of deformable slowly-simulated objects in a stable manner. Stability has been approached in the past by various researchers using passivity theory in order to avoid having to model the human operator closing the haptic loop. None of these solutions however can work well without the use of high update rates and thus break down in the case of haptic interaction with slowly simulated virtual environments such as the ones featuring highly precise deformable objects. This is particularly true for the case of surgical simulation with force feedback, here precision is a key issue and here complexity can reach high levels. The techniques presented in this paper are based on the concepts of local model for haptic interaction adapted to deformable objects. Such approach allows multiple users to stably interact with a same object while feeling the influence of other users on the same object. Experimental results employing a PHANTOM haptic interface are proposed for a simple example
Dynamic performance of mobile haptic interfaces
No full textThe increasing demand for virtual reality applications in several scientific disciplines feeds new research perspectives dealing with robotics, automation, and computer science. In this context, one of the topics is the design of advanced force-feedback devices allowing not only kinesthetic interaction with virtual objects but also locomotion and navigation inside virtual worlds. This has the main advantage to stimulate human vestibular apparatus, thus increasing the overall realism of simulation. Particularly, this paper deals with mobile haptic interfaces (MHIs), built by combining standard force-feedback devices with mobile platforms. We investigated which factors may affect the transparency of this kind of devices, identifying in mobile robot dynamics a possible cause of loss of transparency. Hence, in this paper, we present a method to analyze dynamic performance of an MHI and some basic guidelines to design controller in order to meet desired specifications. Experimental validation of the theoretical results is reported. © 2008 IEEE
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