Functional Magnetic Resonance Imaging (fMRI) is at present one of the most used methodologies for functional brain exploration, both in clinical and research settings. fMRI can noninvasively measure ...neural activity by using specific experimental paradigms. Often, these paradigms require the stimulation of the subject to perform sensorimotor tasks: in the past, the stimuli have been administered manually for investigating fundamental aspects of tactile perception and somatosensory processing. Nowadays, the use of mechatronic devices to stimulate the subject during fMRI studies is growing, also to assure reproducibility, control, and monitoring of task performances. For these reasons, researchers are interested in designing interfaces to be used inside the MRI environment during fMRI studies. For the design of every new device safety and compatibility constraints, imposed by the presence of high static magnetic field, switching magnetic gradients and radiofrequency electromagnetic pulses, must be satisfied. Moreover, it should be considered that functional imaging sequences are even more sensitive to perturbations of the magnetic field than MRI standard diagnostic sequences. Despite several existing devices for use in fMRI studies, an extensive review is still lacking. Our survey aims to introduce into the challenges imposed on the development of fMRI-compatible devices. The current state of the art of compatible devices in fMRI will be presented, pointing out the functionalities and peculiarities of various kinds of device. A particular emphasis will be placed on the tests for the evaluation of fMRI compatibility. This review will be useful both for designers of devices to be used in fMRI studies and for neuroscientists that are having to design fMRI experimental paradigm, and therefore require an overview of existing instruments, but also a knowledge of the benefits and criticism arising from their use.
At present, computer networks are no longer used to connect just personal computers. Smaller devices can connect to them even at the level of individual sensors and actuators. This trend is due to ...the development of modern microcontrollers and singleboard computers which can be easily connected to the global Internet. The result is a new paradigm—the Internet of Things (IoT) as an integral part of the Industry 4.0; without it, the vision of the fourth industrial revolution would not be possible. In the field of digital factories it is a natural successor of the machine-to-machine (M2M) communication. Presently, mechatronic systems in IoT networks are controlled and monitored via industrial HMI (human-machine interface) panels, console, web or mobile applications. Using these conventional control and monitoring methods of mechatronic systems within IoT networks, this method may be fully satisfactory for smaller rooms. Since the list of devices fits on one screen, we can monitor the status and control these devices almost immediately. However, in the case of several rooms or buildings, which is the case of digital factories, ordinary ways of interacting with mechatronic systems become cumbersome. In such case, there is the possibility to apply advanced digital technologies such as extended (computer-generated) reality. Using these technologies, digital (computer-generated) objects can be inserted into the real world. The aim of this article is to describe design and implementation of a new method for control and monitoring of mechatronic systems connected to the IoT network using a selected segment of extended reality to create an innovative form of HMI.
Individuals with walking disability, as a result of pathological conditions or traumas, show a reduction in left ventricle end diastolic volume (EDV). In fact EDV is closely related to the blood ...pressure gradient between the postcaval vein and the right atrium which, during locomotion, is partially due to the calf veins squeezing caused by the rhythmic contraction of the triceps surae and the crushing of the sole of the foot’s veins. In this study, a mechatronic device was applied to nineteen healthy voluntary participants’ lower limbs to test cardiodynamic response to a mechanical intermittent stimulation. The device consisted of inflatable bladders embedded in two shells and acting on the skin of the calf and foot of both legs. The pressure trend on the legs was regulated by a portable programmable logic controller. During the compression protocol to the legs, which involved some sequences of activation-deactivation following a peristaltic compression having a caudal-rostral trend, EDV, assessed by the impedance cardiography technique, increased of about 10% up the pre-test value. The legs compression protocol imposed by means of our pneumatic device might be useful to avoid the negative consequences for cardiovascular performance caused by de-conditioning status linked to walking disabilities.
Introduction
People who are born with arthrogryposis multiplex congenita are typically not able to perform activities of daily living (ADL) due to decreased muscle mass, joint contractures and ...unnatural upper extremity positioning. They are, therefore, potential users of an assistive device capable of aiding in ADL and increasing their independence. A passive orthosis can support the weight of their arm against gravity, allowing them to perform movements with less effort.
Methods
This study presents a prototype design with four degrees-of-freedom that uses musculoskeletal modelling to optimize the stiffness of the springs in the device to partially gravity balance the upper extremity while compensating for the usual internally rotated glenohumeral joint. A single subject-specific musculoskeletal model was developed to simulate the effects of the passive orthosis during 10 static postures during ADL.
Results
For a given configuration using a mono- and a bi-articular spring, the simulations showed that spring stiffnesses of 400 Nm−1 and of 1029 Nm−1, respectively, were able to lower the maximal muscle activity estimated by the musculoskeletal model to a level in which the 10 postures can be realized.
Conclusion
By augmenting residual muscle strength with a partially gravity-balanced passive orthosis, ADLs may be achievable for people with arthrogryposis multiplex congenita.
In this paper, the experimental application of a new class of optical pressure sensors based on polydimethylsiloxane (PDMS)-Au aimed at detecting and classifying millimetric surface damages of ...mechanical components is developed. The device consists of a tapered bended optical fiber, where an optical signal goes across, embedded into a PDMS-gold nanocomposite material (GNM). The sensor is automatically moved for the optical scanning of surfaces by means of a high-accuracy servo motor. After moving and positioning the detector, the sensor output data are acquired and processed in such a way as to pinpoint small notches on a beam. Notches of different lengths to within a few millimeters were scanned to test the realized device capability in recognizing and characterizing very small defects. The experimental results are very encouraging; they exhibit high sensitivity and inspire the use of the sensor in multifarious applications of robotics.
In this paper, the authors present a new strategy for accurately reconstructing an L-shaped obstacle such as some wooden panels opportunely connected so as to form a right angle. The mechatronics ...scanning system consists of four inexpensive ultrasonic sensors moved in three-dimensional (3-D) space by means of a digital motor. The motor rotation is controlled in order to point the sensor array at the target and to obtain distance measurements for each shaft position. Ultrasonic distance sensors propagate large beams and feel the significant effect of multiple reflections. For the sake of excluding all misrepresented distance values at the intersection of the planes, the proposed approach uses powerful mathematical tools together with a physical indicator based on the reflected signal energy. The Fuzzy C-Means (FCM) classification allows partitioning a data set, and the introduced physical indicator is able to select the specific cluster corresponding to the spurious distances. Each remaining cluster permits to calculate the equation of a plane because it is referred to the distance values deriving from a direct reflection. These distances are then transformed considering the sensors directivity and the direction of reflection so as to obtain two sets of 3-D points. Finally, the reconstruction of each plane is achieved by the RANdom SAmple Consensus (RANSAC) in such a way as to better fit these points. The details of this strategy and the experimental tests are shown, demonstrating the applicability and the good results.
Rotary mechanical circulatory support systems Hosseinipour, Milad; Gupta, Rajesh; Bonnell, Mark ...
Journal of rehabilitation and assistive technologies engineering,
2017 Jan-Dec, Letnik:
4
Journal Article
Recenzirano
Odprti dostop
A detailed survey of the current trends and recent advances in rotary mechanical
circulatory support systems is presented in this paper. Rather than clinical reports, the
focus is on technological ...aspects of these rehabilitating devices as a reference for
engineers and biomedical researchers. Existing trends in flow regimes, flow control, and
bearing mechanisms are summarized. System specifications and applications of the most
prominent continuous-flow ventricular assistive devices are provided. Based on the flow
regime, pumps are categorized as axial flow, centrifugal flow, and mixed flow. Unique
characteristics of each system are unveiled through an examination of the structure,
bearing mechanism, impeller design, flow rate, and biocompatibility. A discussion on the
current limitations is provided to invite more studies and further improvements.
Introduction
Gait impairments due to stroke impact millions of individuals throughout the world. Despite the growing interest in automating gait therapy with robotic devices, there is no clear ...evidence that robot-assisted gait therapy is superior to traditional treadmill-based therapy.
Methods
This work investigates the effect of perturbations to the compliance of the walking surface on the paretic leg of impaired walkers. Using a novel robotic device, the variable stiffness treadmill, we apply perturbations to the compliance of the walking surface underneath the non-paretic leg of two hemi-paretic walkers and analyze the kinematic and neuromuscular response of the contralateral (paretic) leg with motion capture and surface electromyography systems.
Results
We present results of evoked muscle activity (predominately tibialis anterior) and increased dorsiflexion in the paretic leg during the swing phase of gait at stiffness values of 60 kN/m and less for all subjects.
Conclusions
This work provides evidence for the first time of reducing the drop-foot effect in the impaired leg of hemiparetic walkers in response to unilateral perturbations to the compliance of the treadmill platform, thus providing direction for targeted robot-assisted gait rehabilitation.
In recent years, the authors studied the possibility of using low frequency in-air ultrasonic sensors in several applications of robotic interest related to the perception and the reconstruction of ...the external environment.
They introduced several methods based on innovative mathematical tools for solving problems, such as the position detection and orientation of a mobile robot with respect to a corridor wall, the correct reconstruction of two orthogonal panels in spite of the effect of multiple reflections affecting the data in the corner zone, and the reconstruction of the boundary walls of a room environment.
All the proposed innovative strategies were tested on a designed mechatronic scanning system consisting of ultrasonic sensors rotated by a servo modular actuator and also with the data from a scanning validated model.
In this review, the main steps and achievements will be presented so as to summarize the research work of recent years as well as reflect on the importance of appropriate and innovative techniques regarding ultrasonic data processing. The originality of the present work concerns the possibility of disposing all the developed approaches as a whole in order to use in-air ultrasonic sensors for robotic perception in several environmental situations.
In this paper the authors present three methods to detect the position and orientation of an observer, such as a mobile robot, with respect to a corridor wall. They use an inexpensive sensor to ...spread a wide ultrasonic beam. The sensor is rotated by means of an accurate servomotor in order to propagate ultrasonic waves towards a regular wall. Whatever the wall material may be the scanning surface appears to be an acoustic reflector as a consequence of low air impedance. The realized device is able to give distance information in each motor position and thus permits the derivation of a set of points as a ray trace-scanner. The dataset contains points lying on a circular arc and relating to strong returns. Three different approaches are herein considered to estimate both the slope of the wall and its minimum distance from the sensor. Slope and perpendicular distance are the parameters of a target plane, which may be calculated in each observer's position to predict its new location. Experimental tests and simulations are shown and discussed by scanning from different stationary locations. They allow the appreciation of the effectiveness of the proposed approaches.
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