Matteo Malosio

Normative Data for an Instrumental Assessment of the Upper-Limb Functionality

Upper-limb movement analysis is important to monitor objectively rehabilitation interventions, contributing to improving the overall treatments outcomes. Simple, fast, easy-to-use, and applicable methods are required to allow routinely functional evaluation of patients with different pathologies and clinical conditions. This paper describes the Reaching and Hand-to-Mouth Evaluation Method, a fast procedure to assess the upper-limb motor control and functional ability, providing a set of normative data from 42 healthy subjects of different ages, evaluated for both the dominant and the nondominant limb motor performance. Sixteen of them were reevaluated after two weeks to perform test-retest reliability analysis. Data were clustered into three subgroups of different ages to test the method sensitivity to motor control differences. Experimental data show notable test-retest reliability in all tasks. Data from older and younger subjects show significant differences in the measures related to the ability for coordination thus showing the high sensitivity of the method to motor control differences. The presented method, provided with control data from healthy subjects, appears to be a suitable and reliable tool for the upper-limb functional assessment in the clinical environment.

A spherical parallel three degrees-of-freedom robot for ankle-foot neuro-rehabilitation

The ankle represents a fairly complex bone structure, resulting in kinematics that hinders a flawless robot-assisted recovery of foot motility in impaired subjects. The paper proposes a novel device for ankle-foot neuro-rehabilitation based on a mechatronic redesign of the remarkable Agile Eye spherical robot on the basis of clinical requisites. The kinematic design allows the positioning of the ankle articular center close to the machine rotation center with valuable benefits in term of therapy functions. The prototype, named PKAnkle, Parallel Kinematic machine for Ankle rehabilitation, provides a 6-axes load cell for the measure of subject interaction forces/torques, and it integrates a commercial EMG-acquisition system. Robot control provides active and passive therapeutic exercises.

Analysis of elbow-joints misalignment in upper-limb exoskeleton

This paper presents advantages of introducing elbow-joints misalignments in an exoskeleton for upper limb rehabilitation. Typical exoskeletons are characterized by axes of the device as much as possible aligned to the rotational axes of human articulations. This approach leads to advantages in terms of movements and torques decoupling, but can lead to limitations nearby the elbow singular configuration. A proper elbow axes misalignment between the exoskeleton and the human can improve the quality of collaborative rehabilitation therapies, in which a correct torque transmission from human articulations to mechanical joints of the device is required to react to torques generated by the patient.

Using Kinect for upper-limb functional evaluation in home rehabilitation: A comparison with a 3D stereoscopic passive marker system

The functional evaluation of the upper-limb can be clinically assessed through the analysis of the kinematics, the dynamics, and measures of motor control. Such measures are usually obtained in a clinical environment with commercial stereoscopic 3D devices that allow to sample kinematics at high frequency and with high accuracy and precision, but that are, on the other hand, expensive, time consuming, and, most of all, are not portable. Consequently, such assessments are available only in clinics. With the aim of developing applications for neurological patients movement analysis in home environment, an experimental study has been conducted to compare the performances of a passive-marker motion capture system with the Kinect. Data were acquired simultaneously with the two systems during reaching against gravity movements. Results suggest that Kinect may be a valid tool for studying reaching against gravity and assessing upper-limb functionality at home in neurological patients.

Kinect One-based biomechanical assessment of upper-limb performance compared to clinical scales in post-stroke patients.

This paper presents a Kinect One sensor-based protocol for the evaluation of the motor-performances of the upper limb of neurological patients during rehabilitative sessions. The assessment provides evaluations of kinematic, dynamic, motor and postural control variables. A pilot study was conducted on three post-stroke neurological patients, comparing Kinect-One biomechanical assessment with the outcomes of some of the most common clinical scales for the evaluation of the upper-limb functionality. Preliminary results indicate coherency between the clinical and instrumental evaluation. Moreover, the Kinect-One assessment seems to provide some complementary quantitative information, consistently integrating the clinical assessment.

Safe obstacle avoidance for industrial robot working without fences

Until now, the presence of fences is a technological barrier for the adoption of robots in Small Medium Enterprises (SME). The work deals with the definition of an intrinsically safe algorithm to avoid collisions between an industrial manipulator and obstacles in its workspace (Standard ISO 10218-1). The suggested strategy aims to offer an industrial solution to the problem: an off-line analysis of the workspace is performed to have an exhaustive and intrinsically description of the static obstacles and a safe spatial grid of “pass-through points” is calculated; an on-line algorithm, based on an enhanced Artificial Potential Field evaluates the most suitable points to avoid collisions against obstacles and perform a realtime replanning the path of the robot. A Matlab toolbox that elaborates STL CAD files has been developed to obtain a full description of the workcell, and the avoidance algorithm has been designed and implemented in a standard industrial controller. Various experimental results are reported by using a COMAU NS16 arm manipulator.

The kinematic architecture of the Active Headframe: A new head support for awake brain surgery

This paper presents the novel hybrid kinematic structure of the Active Headframe, a robotic head support to be employed in brain surgery operations for an active and dynamic control of the patients head position and orientation, particularly addressing awake surgery requirements. The topology has been conceived in order to satisfy all the installation, functional and dynamic requirements. A kinetostatic optimization has been performed to obtain the actual geometric dimensions of the prototype currently being developed.

Robot-assisted upper-limb rehabilitation platform

This work presents a robotic platform for upper-limb rehabilitation robotics. It integrates devices for human multi-sensorial feedback for engaging and immersive therapies. Its modular software design and architecture allows the implementation of advanced control algorithms for effective and customized rehabilitations. A flexible communication infrastructure allows straightforward devices integration and system expandability.

Static and dynamic characterization of the LIGHTarm exoskeleton for rehabilitation

This paper presents LIGHTarm, a passive gravity compensated exoskeleton for upper-limb rehabilitation suitable for the use both in the clinical environment and at home. Despite the low-cost and not actuated design, LIGHTarm aims at providing remarkable back-drivability in wide portions of the upper-limb workspace. The weight-support and back-drivability features are experimentally investigated on three healthy subjects through the analysis of the EMG activity recorded in static conditions and during functional movements. Kinematics is also monitored. Preliminary results suggest that LIGHTarm sharply reduces muscular effort required for limb support, quite uniformly in the workspace, and that remarkable back-drivability is achieved during the execution of functional movements.

High-accuracy hand-eye calibration from motion on manifolds

The hand-eye problem consists in computing the poses between pairs of different coordinate frames fixed to the same rigid body from measurements of such poses as the body moves. Various procedures have been proposed over the past two decades for solving this problem in presence of noise, especially for a robot as the moving body. As a matter of fact, different formulations of the problem in terms of the well known AX=XB or AX=ZB equations implement different flavors of an error minimization procedure, either least-square or non-linear, on the basis of a common algebra. It is shown in this paper that better results in terms of accuracy can be obtained outside the conventional approach. Rather than fitting the calibration matrices out of a number of random poses, the presented method superimposes easily programmable robot poses in order to attain a set of constant manifolds, like points, circles and axes, among the different coordinate frames. Such manifolds are used for identifying the constant relationships between the coordinate frames that are in fact the poses under estimation. The proposed method presents the implementation of a simple robot motion routine for generating the manifolds. Standard mathematical tools are used for fitting the manifolds out of an actual realization of the procedure with tracked markers. The geometry of the proposed manifolds also reduces the propagation of the measurement noise that usually affects the conventional computation based on relative poses. Results are given in simulation and with a real setup in comparison with the most popular state-of-the-art algorithms.