Nowadays the rehabilitation process involves the patient and the therapist, that must interact to recover the motion of limbs and the strength of related muscles to restore the initial functionalities.The therapy relies on the experience and sensitivity of the therapist that identifies the rehabilitation exercises which are necessary to recover the expected ability.To prevent inappropriate practices an interesting aid may come by mixing collaborative robots, namely Cobots, and additive manufacturing technologies.The proper integration of a Cobot assistant and custom-printed training objects enables a significant improvement in the effectiveness of the therapy action and the related user experience since the programmed trajectories can mimic the movements related to activities of daily living.To this aim, this work describes an integrated approach to support the design of Cobot assisted rehabilitative solutions.The object selected by the patient and therapist, the motion pattern, the clamping area, and loads on the limb represents the design requirements.The motion trajectories defining the specific training tasks are the starting point to the optimal placement within the Cobot workspace.Specifically, manipulability maps can provide an objective evaluation of the locations where the exercises are performed at the best of workspace and configuration of the Cobot.A simple upper limb rehabilitation exercise based on a demonstrative handle has been selected to prove the effectiveness of the proposed approach.The results confirm that the manipulability index can be adopted to drive the preliminary design of the Cobotic solution toward a feasible configuration.
Minimization techniques are widely used for retrieving a 3D surface starting from a single shaded image i.e., for solving the shape from shading problem. Such techniques are based on the assumption that expected surface to be retrieved coincides with the one that minimize a properly developed functional, consisting of several contributions. Among the possible contributes defining the functional, the so called “smoothness constraint” is always used since it guides the convergence of the minimization process towards a more accurate solution. Unfortunately, in areas where actually brightness changes rapidly, it also introduces an undesired over-smoothing effect. The present work proposes two simple yet effective strategies for avoiding the typical over-smoothing effect, with regards to the image regions in which this effect is particularly undesired (e.g., areas where surface details are to be preserved in the reconstruction). Tested against a set of case studies the strategies prove to outperform traditional SFS-based methods.
Abstract The objective of this study is to establish a new methodology for the metrological characterization of interactive multi-camera systems. In the case of 3D system highly adapted to specific needs the accuracy evaluation cannot be performed using standard state-of-the-art techniques. To this end, the metrological characterization techniques used in the literature were investigated in order to define a new methodology that can be adjusted to each device by making the appropriate modifications. The proposed strategy is adopted for the metrological characterization of a new interactive multi-camera system for the acquisition of the arm.
Abstract Soft robots have gained significant interest over the past two decades due to their high flexibility and adaptability to various working conditions. Recent advances in engineering and innovative materials have enabled the design and production of sophisticated soft robotic systems with enhanced capabilities. Additive manufacturing has accelerated the development of soft actuators, unlocking complex kinematics, improving their effectiveness and allowing the production of task-specific actuators. 3D printed soft actuators can gain advantage of the fabricability of complex geometries to guarantee improved mobility and grasping abilities. However, challenges remain in investigating the durability of such devices. Limits of most recent advanced manufacturing methods and materials, with this respect, are still to be fully explored.In this work, bellow-type pneumatic soft actuators fabricated through Fused Filament Fabrication in thermoplastic polyurethane (TPU) are tested to evaluate their fatigue behaviour. Silicone rubber casted actuators are included to provide a point of reference. The actuators integrated resistive flex sensors to monitor bending motion. Fatigue tests were performed with cycles of inflation and deflation until failure. Results showed that 3D printed TPU actuators are capable of whitstanding a significant amount of cycles before failure, ultimately being comparable with alternative fabrication technologies. Overall, this study proves the potential of the Fused Filament Fabrication process for the fabrication of durable, long-lasting pneumatic soft actuators.
With the aim of retrieving 3D surfaces starting from single shaded images, i.e. for solving the widely known shape from shading problem, an important class of methods is based on minimisation techniques where the expected surface to be retrieved is supposed to be coincident with the one that minimise a properly developed functional, consisting of several contributions. Despite several different contributes that can be explored to define a functional, the so called 'smoothness constraint' is a cornerstone since it is the most relevant contribute to guide the convergence of the minimisation process towards a more accurate solution. Unfortunately, in case input shaded image is characterised by areas where actual brightness changes rapidly, such a constraint introduces an undesired over-smoothing effect for the retrieved surface. The present work proposes an original strategy for avoiding such a typical over-smoothing effect, with regard to the image regions in which this is particularly undesired such as, for instance, zones where surface details are to be preserved in the reconstruction. The proposed strategy is tested against a set of case studies and compared with other traditional SFS based methods to prove its effectiveness.
