An anthropomorphic underactuated prosthetic hand, endowed with position and force sensors and controlled by means of myoelectric commands, is used to perform experiments of hierarchical shared control. Three different hierarchical control strategies combined with a vibrotactile feedback system have been developed and tested by able-bodied subjects through grasping tasks used in activities of daily living (ADLs). The first goal is to find a good tradeoff between good grasping capabilities and low attention required by the user to complete grasping tasks, without addressing advanced algorithm for electromyographic processing. The second goal is to understand whether a vibrotactile feedback system is subjectively or objectively useful and how it changes users' performance. Experiments showed that users were able to successfully operate the device in the three control strategies, and that the grasp success increased with more interactive control. Practice has proven that when too much effort is required, subjects do not do their best, preferring, instead, a less-interactive control strategy. Moreover, the experiments showed that when grasping tasks are performed under visual control, the enhanced proprioception offered by a vibrotactile system is practically not exploited. Nevertheless, in subjective opinion, feedback seems to be quite important.

The paper presents a controller for a multi-fingered underactuated prosthetic hand based on tendon transmission. The control architecture is implemented in two subsequent and different phases. The first one is the pre-shaping of the hand, based on the grasp type is implemented by stand-alone motion controllers using PID position control algorithms. The desired force closure value is calculated according to the pre-shape measured tendons tension and to the grasping force. In the second phase, the involved fingers rapidly close around the object to perform a balanced distribution of the forces within the hand, as it happens in the human hand. The controller is thus able to perform successfully many stable grasps. An overview of the hardware architecture and the results in terms of grasping capabilities based on Cutkosky grasp taxonomy are also presented

This paper presents recent results aimed at developing a functional prosthetic hand characterized by an EMG-control and by a simple and low cost fabrication technology. In order to overcome some limitations of current prosthetic hands mainly related to the poor functionality and controllability, the prosthetic hand has been designed following a biomechatronic approach based on biologically-inspired design solutions. The core of the project described in this paper is the fabrication of a compliant under-actuated prosthetic hand: the structure of the hand (both palm and fingers) is moulded as a soft polymeric single part with compliant joints and embedded tendon driven underactuated mechanism for providing adaptive grasp. In order to make user trials, the hand is equipped with simple but functional EMG-based control of the single motor incorporated in the hand, and is integrated with a prosthesis socket. The paper presents the biomechatronics design, the fabrication process, the integration of the prosthetic device and first experimental results.

In this paper, some recent results about the experimental trials we are performing on a functional prosthetic hand characterized by an EMG-control and by a simple and low cost fabrication technology are shown. The innovation described in this paper is the fabrication of a compliant under-actuated prosthetic hand. The structure of the hand (both palm and fingers) is moulded as a soft polymeric single part with compliant joints and embedded tendon driven under-actuated mechanism for providing adaptive grasp. The prosthetic hand has been designed following a biomechatronic approach based on biologically-inspired design solutions. We describe the second release of this prosthesis. The evaluating tests are related to the maximum force exerted during grasping and to the fatigue problems occurring with cables and joint.

In this paper a wearable biomechatronic system (named MEKA) for the analysis of knee movements in two degrees of freedom is presented. The system has been designed in order to be used not only in laboratory environment (as many other commercial systems) but also in real-life conditions (e.g. for experiments on sport biomechanics). The performance of the MEKA device and of two commercial systems (an electrogoniometer and a camera-based motion analyzer) has been compared. The results showed that the MEKA system is able to obtain similar or even better performance during movements. After this preliminary assessment phase, the MEKA system has been used to analyse the modifications of motor performance of elderly and young people during gait using a "dual-task" approach. The results show that elderly people seems to be more affected by the increase cognitive efforts. In conclusion, the MEKA system seems to be able to provide interesting information for experiments on biomechanics and motor control.

The aim of this paper was to analyse the feasibility of using a sensor-based glove as a tool for the assessment of hand function in persons with orthopedic disorders such as rhizoarthrosis. A glove embedding 20 Hall-effect sensors was used for this purpose. Its performance in terms of repeatability were preliminary investigated in order to define an effective strategy for the use of the glove in these applications. After this preliminary phase, focused clinical experiments were carried out in order to verify the existence of differences usable for performance assessment in the postures of the hand of able-bodied and subjects affected by rhizoarthrosis during grasping. The data were processed by using the principal component analysis (PCA) technique. The preliminary results of these experiments showed that the use of the first and second principal components can allow to discriminate between able-bodied and disabled persons and also between disabled persons before and after the surgical intervention. For this reason, this approach could represent an effective tool for the surgeon during the rehabilitation process in this particular situation. Further experiments will be carried out in the future in order to confirm these preliminary results. Moreover, a new calibration procedure of the sensor-based glove will be developed in order to improve the performance of the glove.