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Background: Wearable powered robotic exoskeletons allow patients with complete spinal cord injury (SCI) to practice over-ground real-world gait scenarios. The global functional interaction subject-exoskeleton is a key factor to produce interlimb coordinated movements. Efficacy and efficiency of over-ground walking abilities using powered exoskeletons are related not only to the symbiotic sensory-motor interaction subject-exoskeleton but also to exoskeleton control., Aim: Assess if walking ability of motor complete SCI patients at thoracic or lower level, using a wearable powered exoskeleton (ReWalk), can be influenced by different exoskeleton software control., Design: Observational study; an open, non-comparative, non-randomized study., Setting: A single neurological rehabilitation center for inpatients and outpatients., Population: Fifteen SCI chronic patients (4 females and 11 males) were recruited and divided in two groups: group 1, trained with the first software generation of ReWalk, and group 2, trained with the second software generation, a software upgrade of the previous version., Methods: Subjects were trained during three 60-minute sessions a week, during at least eight weeks using ReWalk, a wearable lower limb powered exoskeleton that allows thoracic or lower level motor-complete individuals with SCI to walk, stand, sit and climb/descend stairs. Outcome measures, collected at the end of the training period wearing the exoskeleton, were: 6-min Walking Test, 10-m Walking Test, and the time necessary to pass from sitting to standing and start to walk (STS-time). For each group Pearson Coefficient was calculated to explore correlations between the subjects' characteristics and gait performance reached at the end of the training period., Results: Group 1 showed correlation between performances and weight, height, neurological lesion level, while group 2 showed no correlation between performances weight and height, but correlation only with neurological lesion level. Group 2 covered more distance in 6 min (+124.52%) and required less time (-70.34%) to perform 10 mtWT and to STS-time (-38.25%) if compared to group 1., Conclusions: ReWalk allows chronic complete spinal cord injury patients to perform over-ground walking. Different exoskeleton software control of the smoothness of the gait pattern improves functional outcome, eliminating the relationship between anthropometric factors and gait performances. The smoothness of the kinematic control of the lower limbs of the exoskeleton is a key factor to facilitate human-robot interaction and to increase walking abilities of the subject., Clinical Rehabilitation Impact: To underline how the kinematic control of the exoskeleton influences the walking abilities of the complex system subject-exoskeleton.

This study proposes an experimental method to estimate personalized inertial parameters of upper limbs during handcycling by using a planar dynamic model. The handle forces are expressed as a product of a matrix describing the kinematics terms and a vector of inertial parameters of arm and forearm. The parameters are estimated by measuring the handle forces during a suitable "passive test" and inverting the mentioned matrix. The data were acquired while an operator actuated the handle and the subject's muscles were relaxed. To validate the estimation procedure, it was applied to a custom-made artificial arm mechanism, and the results were compared with its known parameters. The method was then used to estimate the inertial parameters of 6 human subjects. The estimated parameters were used to compute the exchanged forces and compared with the measured ones obtaining an average error of 14% both for F x and F y . These errors are significantly smaller than those obtained using dynamic parameters extracted from the literature to compute the forces, which were 50% for F x and 19% for F y . An individual evaluation of inertial parameters better describes interaction forces during handcycling, especially for subjects whose body structures are different from the average population.

The paper presents an innovative mechanism for the singularization of micro-spheres, which can be effectively employed in a diverse range of robotized applications in micro-electronics and micro-mechanics. Many miniaturized devices are currently being developed and consist of different micro-components to be precisely assembled. The demanding product and process requirements can be met by automating the assembly phases, which include sorting and feeding the micro-components. Therefore, accurate, high-throughput, and modular mechanisms and tools able to supply a number of micro-components, or even a single element for the subsequent operations, play a significant role. In this context, this work focused on the development of a novel strategy for separating a single component from an unstructured stock of identical parts, in particular of micro-spheres with diameters of 0.2⁻1 mm. Suitable expedients were considered to overcome the adhesive effects that can become significant at the micro-scale due to the very small size and low mass of the micro-spheres. The paper describes the operating principle and the actuation strategies of the mechanism. The design and the development of a prototype for singularizing micro-spheres with a diameter of 0.6 mm are thoroughly discussed. Finally, the results of experimental singularization tests demonstrate the method effectiveness and the mechanism performance., Competing Interests: The authors declare no conflict of interest.

Bioelectric prosthesis are those mechatronical devices able to substitute the total or partial loss of a limb or a system, and controlled by the patient thanks to wilful bioelectric signals, such as muscular contractions (electromyographic signals, EMG) or activation of specific encephalic areas (which can be revealed by encephalogram, EEG). At the end of an analysis of the devices currently in literature and on the market, the present paper collects and synthesize the possible classification strategies of these prosthetic devices, paying particular attention also to the classification obtained by possible control strategies of the prosthesis. This summary aims to support and sustain physicians and patients along the identification of the most appropriate prosthesis, for the specific subject, the choice of the "optimal" device, must consider also patient needs and expectations, possible pathological constraints and technological complexity of the system. This paper presents, after a brief theoretical introduction about the background, a short description of materials and methods implemented in order to identify classification typologies; the main results, collected in 2 tables, will be then described, and commented highlighting advantages and limbs of the proposed classifications.