Studio di sistemi robotici attivi interagenti per rieducazione motoria

Stroke is the third leading cause of death in industrialized countries and is recognized as the most costly disease in terms of money and quality of life. Disability in survivors in at least one of activities of daily living is present in 67.6% of patients. Rehabilitation training is the more effective the more it is early, intensive and full of multi-sensory stimuli. Patients require an individual approach to physiotherapy for at least 3 hours a day, often not feasible. It comes the need to seek new tools in order also to contain costs. The aim of this work is the design of a novel active hand orthosis for neurorehabilitation. The functional and mechanical properties derived from a careful study of anatomy, joint physiology and hand grip strength. At the same time it's prsented the design, development and analysis of an architecture of teleoperation system for remote assessment of the clinical status of the hand that makes use of the existing prototype of a single-dof active hand orthosis that has highlighted the shortcomings and key points of the previous project. Many authors agree that complex and multi-dof devices for hand rehabilitation, as the analysis of the current state of art reveals to be the majority of them, are not necessary for the rehabilitation of moderate and severe attacks stroke. This paper traces then all phases of the design, from the functional design by means of synthesis algorithms to mechanical one defining lines, shapes, structure and transmission of the machine, up to the wiring diagram and control project, validated through experimental tests in the developed tele-assessment system. Finally, modules are implemented for the management of augmented feedbacks and/or substitutive feedbacks, such as the underestimated auditory feedback, that may improve and make more efficient the motor re-learning of post-stroke patients. This comes from some performed studies at the University of California - Irvine (UCI), under the direction of Prof. David J. Reinkensmeyer, and described here, in order to find the role of auditory feedback in motor control and motor adaptation, in addition or in sensory substitution to other sensory modalities, in the presence of altered kinematics and dynamics.L’ictus è la terza causa di morte nei paesi industrializzati ed è riconosciuto come la patologia più costosa in termini monetari e di qualità della vita. Nei sopravvissuti la disabilità in almeno una delle attività quotidiane è presente nel 67,6% dei pazienti colpiti. Il trattamento riabilitativo è tanto più efficace quanto più risulta precoce, intensivo e ricco di stimoli multisensoriali. I pazienti necessitano di un approccio fisioterapico individuale di almeno tre ore al dì, spesso non praticabile. Nasce la necessità di ricercare nuovi strumenti con lo scopo anche di un contenimento dei costi. Obiettivo di questo lavoro è il progetto di una nuova ortesi motorizzata per la rieducazione motoria della mano. Le specifiche funzionali e meccaniche derivano da un attento studio dell’anatomia, della fisiologia articolare e della forza di prensione dell’arto. In parallelo vengono presentatati la progettazione, lo sviluppo e l’analisi di un’architettura di teleoperazione per la valutazione da remoto dello stato clinico della mano che fa uso del prototipo preesistente di ortesi motorizzata ad un g.d.l. che ha messo in luce mancanze e punti di forza del progetto precedente. Molti autori affermano che dispositivi per la mano complessi e multi g.d.l., che dall’analisi dell’attuale stato dell’arte sono la maggior parte, non sono necessari per la riabilitazione di gravi e moderati attacchi ictali. Il presente lavoro ripercorre allora tutte le fasi della progettazione, da quella funzionale tramite algoritmi di sintesi cinematica, a quella meccanica che definisce struttura e trasmissione della macchina, fino allo schema elettrico e al progetto di controllo, validato con test sperimentali nel sistema di televalutazione sviluppato. Infine, sono predisposti moduli di gestione di feedback aumentati e/o sostitutivi che potrebbero migliorare il riapprendimento motorio di pazienti post-ictus. Ciò a fronte di alcuni studi condotti presso l’Università della California Irvine (UCI), sotto la supervisione del Prof. David J. Reinkensmeyer, e qui descritti per chiarire il ruolo di un feedback altamente sottovalutato come quello uditivo nel controllo e nell’adattamento motorio in sostituzione o in aggiunta ad altre modalità sensoriali, in presenza di cinematiche e dinamiche alterate

Employing spatial sonification of target motion in tracking exercises

This paper presents the results of an experiment in which the effect of spatial sonification of a moving target on the user's performance during the execution of basic tracking exercises was investigated. Our starting hypothesis is that a properly designed multimodal continuous feedback could be used to represent temporal and spatial information that can in turn improve performance and motor learning of simple target following tasks. Sixteen subjects were asked to track the horizontal movement of a circular visual target by controlling an input device with their hand. Two different continuous task-related auditory feedback modalities were considered, both simulating the sound of a rolling ball, the only difference between them being the presence or absence of binaural spatialization of the target's position. Results demonstrate how spatial auditory feedback significantly decreases the average tracking error with respect to visual feedback alone, contrarily to monophonic feedback. It was thus found how spatial information provided through sound in addition to visual feedback helps subjects improving their performance

Design and construction of a variable-aperture gripper for flexible automated assembly

The growing market demand for a wide variety of product models and small batch production makes flexible robotized production systems an emerging need in industry. Today, in manufacturing applications, general purpose grippers are not very considered, and robot end effectors are properly designed for the specific task with a strongly limited versatility. Flexibility is thus usually obtained by using a different tool for each family of parts: a tool changing system allows the robot to rapidly replace the tool on the end effector; tools are stored in a tool magazine allocated in the workcell. However, such systems are expensive and their use can affect the working cycle-time. This paper presents the design and testing of a variable-aperture, cost-effective gripper, capable of adapting its aperture (grasp width) to different handling demands, without affecting the working-cycle time of the production system. The solution proposed consists of (1) an electrically-actuated mechanism, which allows it to satisfy flexibility requirements, by regulating the aperture in hidden time; (2) a pneumatically-actuated mechanism to achieve high performance in open/close operations. Simulations and preliminary tests showed that this type of design can be a suitable solution to increase flexibility in robotized workcells without increasing the cycle time

Throughput maximization and buffer design of robotized flexible production systems with feeder renewals and priority rules

Automation is a powerful way to reduce production costs. The growing market demand for a wide set of models and small batch production make flexible automated production systems an emerging need in several industries. The aim of this paper is to analyze and to maximize the performance of robotized flexible production systems consisting of a robot, feeder, working station, and unloading station, where the operations of the working cycle are scheduled using a sequencing algorithm based on priority rules. Since the working cycle is not predefined, the cycle time is strongly influenced by the parameters characterizing the workcell such as the workcell layout, the robot transfer movements, the feeder, the working operations, and the presence of a buffer between stations. In this work, we modeled the working cycle of a simple but representative layout of an industrial robotized flexible production system with and without buffer, and we implemented a recursive algorithm to estimate the cycle time. The analytical model derived was compared to the experimental results, obtained by using a prototype of the flexible production workcell. The results show that the analytical model is a powerful tool to estimate the performance of the workcell and to identify the design variables or their combinations that maximize the throughput

Trajectory planning of a suspended cable driven parallel robot with reconfigurable end effector

In this paper, a new suspended cable driven parallel robot (CDPR) with reconfigurable end effector is presented. This robot has been conceived for pick and place operations in industrial environments. For such applications, the possibility to change the configuration of the cables at the end-effector level is a promising way to avoid collisions with obstacles in the approaching phases, while reducing at the same time the duration of motion in the remaining part of the trajectory. An optimized trajectory planning algorithm is proposed, which implements a pick and place operation in the operational space with dynamic on-line reconfiguration of the end effector. The results on a simplified scenario demonstrate the ability of the system to obtain reduced movement times together with obstacle avoidance

Effects of kinesthetic and cutaneous stimulation during the learning of a viscous force field

Haptic stimulation can help humans learn perceptual motor skills, but the precise way in which it influences the learning process has not yet been clarified. This study investigates the role of the kinesthetic and cutaneous components of haptic feedback during the learning of a viscous curl field, taking also into account the influence of visual feedback. We present the results of an experiment in which 17 subjects were asked to make reaching movements while grasping a joystick and wearing a pair of cutaneous devices. Each device was able to provide cutaneous contact forces through a moving platform. The subjects received visual feedback about joystick\u2019s position. During the experiment, the system delivered a perturbation through (1) full haptic stimulation, (2) kinesthetic stimulation alone, (3) cutaneous stimulation alone, (4) altered visual feedback or (5) altered visual feedback plus cutaneous stimulation. Conditions 1, 2 and 3 were also tested with the cancellation of the visual feedback of position error. Results indicate that kinesthetic stimuli played a primary role during motor adaptation to the viscous field, which is a fundamental premise to motor learning and rehabilitation. On the other hand, cutaneous stimulation alone appeared not to bring significant direct or adaptation effects, although it helped in reducing direct effects when used in addition to kinesthetic stimulation. The experimental conditions with visual cancellation of position error showed slower adaptation rates, indicating that visual feedback actively contributes to the formation of internal models. However, modest learning effects were detected when the visual information was used to render the viscous field

Changes in muscle coordination patterns induced by exposure to a viscous force field

none4siBackground: Robotic neurorehabilitation aims at promoting the recovery of lost function after neurological injury by leveraging strategies of motor learning. One important aspect of the rehabilitation process is the improvement of muscle coordination patterns, which can be drastically altered after stroke. However, it is not fully understood if and how robotic therapy can address these deficits. The aim of our study was to find how muscle coordination, analyzed from the perspective of motor modules, could change during motor adaptation to a dynamic environment generated by a haptic interface. Methods: In our experiment we employed the traditional paradigm of exposure to a viscous force field to subjects that grasped the handle of an actuated joystick during a reaching movement (participants moved directly forward and back by 30 c m). EMG signals of ten muscles of the tested arm were recorded. We extracted motor modules from the pooled EMG data of all subjects and analyzed the muscle coordination patterns. Results: We found that the participants reacted by using a coordination strategy that could be explained by a change in the activation of motor modules used during free motion and by two complementary modules. These complementary modules aggregated changes in muscle coordination, and evolved throughout the experiment eventually maintaining a comparable structure until the late phase of re-adaptation. Conclusions: This result suggests that motor adaptation induced by the interaction with a robotic device can lead to changes in the muscle coordination patterns of the subject.noneOscari, Fabio; Finetto, Christian; Kautz, Steve A.; Rosati, GiulioOscari, Fabio; Finetto, Christian; Kautz, Steve A.; Rosati, Giuli