Stroke patients are often affected by hand impairment. Literature shows different experiences of robotic rehabilitation that is able to prove an intensive and effective therapy. A preliminary analysis of the state of the art evidenced lacks in hand robotic rehabilitation devices. Thus, this work proposes a new rehabilitation device for hand rehabilitation based on a compliant transmission. The mechanical power generator is not on the hand to reduce the weight of the device. The mechanical model of the system is descripted. Experimental results on 126 stroke patients evidenced the efficacy of this device

Investigations about the feasibility of delivery systems with unmanned aerial vehicles (UAVs) or drones have been recently expanded, owing to the exponential demand for goods to be delivered in the recent years, which has been further increased by the COVID-19 pandemic. UAV delivery can provide new contactless delivery strategies, in addition to applications for medical items, such as blood, medicines, or vaccines. The safe delivery of goods is paramount for such applications, which is facilitated if the payload is embedded in the main drone body. In this paper, we investigate payload solutions for medium and small package delivery (up to 5 kg) with a medium-sized UAV (maximum takeoff of less than 25 kg), focusing on (i) embedded solutions (packaging hosted in the drone fuselage), (ii) compatibility with transportation of medical items, and (iii) user-oriented design (usability and safety). We evaluate the design process for possible payload solutions, from an analysis of the package design (material selection, shape definition, and product industrialization) to package integration with the drone fuselage (possible solutions and comparison of quick-release systems). We present a prototype for an industrialized package, a right prism with an octagonal section made of high-performance double-wall cardboard, and introduce a set of concepts for a quick-release system, which are compared with a set of six functional parameters (mass, realization, accessibility, locking, protection, and resistance). Further analyses are already ongoing, with the aim of integrating monitoring and control capabilities into the package design to assess the condition of the delivered goods during transportation.

This work regards on the design of a cylindrical cam indexing mechanism with a motion law that passes through a positional precision point. A numerical algorithm is proposed to solve this problem and, particularly, a genetic algorithm. The algorithm and the encoding of the problem are described.

Structural deformations are one of the most significant factors that affects machine tool (MT) positioning accuracy. These induced errors are complex for accurate representation by a model, nevertheless they need to be evaluated and predicted in order to increase the machining performance. This paper presents a novel approach to calibrate a machine tool in real-time, analyzing the thermo-mechanical errors through fiber Bragg grating (FBG) sensors embedded in the MT frame. The proposed configuration consists of an adaptronic structure of passive materials, Carbon Fiber Reinforced Polymers (CFRP), equipped with FBG sensors that are able to measure in real-time the deformed conditions of the frame. By using a proper thermo-mechanical kinematic model, the displacement of the end effector may be predicted and corrected when it is subjected to external undesired factors. By starting from a set of Finite Element (FE) simulations to develop a model able to describe the MT structure stresses, a prototype has been fabricated and tested. The aim of this study was to compare the numerical model with the experimental tests using FBG sensors. The experimental campaign has been performed by varying the structure temperature over time and measuring the tool tip point (TTP) positions. The obtained results showed a substantial matching between the real and the predicted position of the TTP, thereby confirming the effectiveness of the proposed system.

Ensuring the safety of physical human–robot interaction (pHRI) is of utmost importance for industries and organisations seeking to incorporate robots into their workspaces. To address this concern, the ISO/TS 15066:2016 outlines hazard analysis and preventive measures for ensuring safety in Human–Robot Collaboration (HRC). To analyse human–robot contact, it is common practice to separately evaluate the “transient” and “quasi-static” contact phases. Accurately measuring transient forces during close human–robot collaboration requires so-called “biofidelic” sensors that closely mimic human tissue properties, featuring adequate bandwidth and balanced damping. The dynamics of physical human–robot interactions using biofidelic measuring devices are being explored in this research. In this paper, one biofidelic sensor is tested to analyse its dynamic characteristics and identify the main factors influencing its performance and its practical applications for testing. To this aim, sensor parameters, such as natural frequency and damping coefficient, are estimated by utilising a custom physical pendulum setup to impact the sensor. Mathematical models developed to characterise the sensor system and pendulum dynamics are also disclosed.

Micromachining processes deal with the production of parts characterized by features in the micro range (i.e., with dimension lower than 1 mm). Several works are present in literature analyzing the tool behaviors, the material influence on the process, and the machine design. In fact, the downsize of the process up to the microscale needs a full review of all the knowledge coming from the meso and macro scale. As a consequence, machines suitable for micromachining processes were recently introduced in the market. Usually, these machines are classified by the classical gantry layout structure supported by a granite frame and, in order to guarantee the needed requirements of precision and accuracy in the micro scale, they are based on fluid-supported axes and active and/or passive vibration control systems. This paper proposes a new concept design: a high precision machine (HPM) based on an innovative layout exploiting a differential mechanism with three motors for two degrees of freedom using pulleys and metal belts. This new layout exhibits relevant advantages. The most significant is that all the worktable servo drives, that moves along x and y axes, are ground-fixed. This allows to isolate the working area of the machine from the servo drives. The system of pulleys and belts holding the working table slides on air bearings in order to minimize the micro vibrations induced by all the drives. A further peculiarity of the machine consists of the double z-axis each of them is motorized by a micrometer slide with linear absolute encoder. The first z-axis is equipped with a spindle for performing micro machining processes (drilling and milling). The second z-axis is equipped with a laser head for micro ablation. The servo drives of the two z-axes are controlled by the same control system of the worktable. Another important feature of the proposed layout is that the differential configuration of the xy mechanism admits the use of a constant speed signal to each control reference with no output displacements. This allows to guarantee non-inversion of motion of the servo-drives and so the avoidance of problems due to backlash and/or static friction. Drives are controlled by position and speed control loops with PID architecture, anti-windup and feed forward strategies. Controllers have been tuned by the use of a genetic algorithm applied to a dynamic model of the system. As a general consideration, the quality of the investigated micro machining processes can be improved with the designed machine structure.