Sarah Cosentino

Development of a real-time IMU-based motion capture system for gait rehabilitation

A common problem among elderly people is the loss of motor ability. Rehabilitation exercises can help these people recover strength and maintain a good level of mobility. However, high costs and the need for special equipment make professional rehabilitation impractical for regular use in daily life, precluding elderly the possibility to perform focalized training at home. The idea of telerehabilitation is becoming more and more concrete with the rapid development of internet technology. Telerehabilitation would allow the user to perform exercises at home with online professional direction from the doctor. However, at the present state, the doctor cannot obtain real-time and quantitative data from the user, and this limits the training effectiveness. To overcome this problem, an extremely miniaturized, portable motion capture system, named WB-4R, has been developed. Calibration and real-time link orientation reconstruction are very important to improve the accuracy in real-time measurement. In this paper, using the positive results of preliminary experiments on lower limbs, the authors will show the feasibility of the method and confirm the effectiveness of the developed system.

Natural human–robot musical interaction: understanding the music conductor gestures by using the WB-4 inertial measurement system

This paper presents an inertial measurement unit-based human gesture recognition system for a robot instrument player to understand the instructions dictated by an orchestra conductor and accordingly adapt its musical performance. It is an extension of our previous publications on natural human–robot musical interaction. With this system, the robot can understand the real-time variations in musical parameters dictated by the conductor’s movements, adding expression to its performance while being synchronized with all the other human partner musicians. The enhanced interaction ability would obviously lead to an improvement of the overall live performance, but also allow the partner musicians, as well as the conductor, to better appreciate a joint musical performance, thanks to the complete naturalness of the interaction. Graphical Abstract

Human-humanoid robot social interaction: Laughter

In this paper, we describe a human gesture recognition system developed to make a humanoid robot understand non-verbal human social behaviors, and we present the results of preliminary experiments to demonstrate the feasibility of the proposed method. In particular, we have focused on the detection and recognition of laughter, a very peculiar human social signal. In fact, although it is a direct form of social interaction, laughter is classified as semi voluntary action, can be elicited by several different stimuli, and it is strongly associated with positive emotion and physical well-being. The possibility of recognize, and further elicit laughter, will help the humanoid robot to interact in a more natural way with humans, to build positive relationships and thus be more socially integrated in the human society.

Walking assessment in the phase space by using ultra-miniaturized Inertial Measurement Units

Physical therapy helps patients to restore the use of the musculoskeletal and the nervous systems through the use of specifics techniques and exercises. The introduction of measurement systems for patient assessment may allow detection of initial stage of diseases, an objective severity assessment, and efficient delivery of drugs and therapies. In rehabilitation centers, sometimes there are specific devices and methodologies available for the locomotion assessment. However, the measurements are usually carried out in a short time slot and this could lead to an overestimation of the walking abilities. The authors propose a system, named WB-4R, which can provide a fast and objective walking assessment using a set of Inertial Measurement Units (IMUs). The WB-4R can be used for the gait analysis in rehabilitation centers or at home because it is compact and relatively maintenance-free. In this paper, it will be shown that our system is able to reconstruct the joint angles of lower limbs and build a foot phase space diagram during straight line walking. Furthermore, we compared the results with an optical system used in the clinical practice.

Use of an ultra-miniaturized IMU-based motion capture system for objective evaluation and assessment of walking skills

The increasing age of the world population is posing new challenges to our society, such as how to keep this aging population healthy and active despite of the age. In recent years, there has been a lot of interest for gait analysis for rehabilitation purposes as well as for performance assessment of this aging population. While current systems work well, they still have several limitations. Cost, need for specialized personnel, need to be used in a research center, and sporadic measurement prevent these systems from being widely used. The authors propose the use of extremely miniaturized, portable measurement systems, which can be worn by the users during their everyday life, and can monitor their gait over a long timespan. This paper presents the preliminary experiments with such a system.

Quantitative Laughter Detection, Measurement, and Classification—A Critical Survey

The study of human nonverbal social behaviors has taken a more quantitative and computational approach in recent years due to the development of smart interfaces and virtual agents or robots able to interact socially. One of the most interesting nonverbal social behaviors, producing a characteristic vocal signal, is laughing. Laughter is produced in several different situations: in response to external physical, cognitive, or emotional stimuli; to negotiate social interactions; and also, pathologically, as a consequence of neural damage. For this reason, laughter has attracted researchers from many disciplines. A consequence of this multidisciplinarity is the absence of a holistic vision of this complex behavior: the methods of analysis and classification of laughter, as well as the terminology used, are heterogeneous; the findings sometimes contradictory and poorly documented. This survey aims at collecting and presenting objective measurement methods and results from a variety of different studies in different fields, to contribute to build a unified model and taxonomy of laughter. This could be successfully used for advances in several fields, from artificial intelligence and human-robot interaction to medicine and psychiatry.

Assessment of walking quality by using Inertial Measurement Units

A device for the gait analysis during a long-distance walking is important for the correct assessment of patients during the rehabilitation. This device should be able to measure all gait parameters in a single unit. In addition, it is required that the measurement system is not spatially constrained. In our group, we have been developing a new wireless system, namely WB-4R, composed of Inertial Measurement Units, to be used in rehabilitation centers for gait analysis that is cheap, small, and relatively maintenance-free. This paper presents the results of a pilot study conducted with healthy subjects. The system was able to detect the gait phase and provide frequency analysis of the angular velocity and acceleration of the lower limbs.

Comparison of gait event detection from shanks and feet in single-task and multi-task walking of healthy older adults

Automatic and objective detection algorithms for gait events from MEMS Inertial Measurement Units data have been developed to overcome subjective inaccuracy in traditional visual observation. Their accuracy and sensitivity have been verified with healthy older adults, Parkinsons disease and spinal injured patients, using single-task gait exercises, where events are precise as the subject is focusing only on walking. Multi-task walking instead simulates a more realistic and challenging scenario where subjects perform secondary cognitive task while walking, so it is a better benchmark. In this paper, we test two algorithms based on shank and foot angular velocity data in single-task, dual-task and multi-task walking. Results show that both algorithms fail when the subject slows extremely down or pauses due to high cognitive and attentional load, and, in particular, the first stride detection error rate of the foot-based algorithm increases. Stride time is accurate with both algorithms regardless of walking types, but the shank-based algorithm leads to an overestimation on the proportion of swing phase in one gait cycle. Increasing the number of cognitive tasks also causes this error with both algorithms.

Development of a Humorous Humanoid Robot Capable of Quick-and-Wide Arm Motion

This letter describes the development of a humanoid arm with quick-and-wide motion capability for making humans laugh. Laughter is attracting research attention because it enhances health by treating or preventing mental diseases. However, laughter has not been used effectively in healthcare because the mechanism of laughter is complicated and is yet to be fully understood. The development of a robot capable of making humans laugh will clarify the mechanism how humans experience humor from stimuli. Nonverbal funny expressions have the potential to make humans laugh across cultural and linguistic differences. In particular, we focused on the exaggerated arm motion widely used in slapsticks and silent comedy films. In order to develop a humanoid robot that can perform this type of movement, the required specification was calculated from slapstick skits performed by human comedians. To meet the required specifications, new arms for the humanoid robot were developed with a novel mechanism that includes lightweight joints driven by a flexible shaft and joints with high output power driven by a twin-motor mechanism. The results of experimental evaluation show that the quick-and-wide motion performed by the developed hardware is effective at making humans laugh.

Angular sway propagation in One Leg Stance and quiet stance with Inertial Measurement Units for older adults

Postural stability degrades with age, threating the health and life quality of the older adults. One Leg Stance (OLS) is one of the standard and commonly adopted assessments for postural stability, and the postural sway in OLS has been demonstrated to be related with age. The propagation of postural sway between body segments could be a hint to the underlying mechanism of balance control. However, it is not yet fully understood. Therefore, the aim of this paper was to study the angular sways and their propagation of the head, trunk, and lower limb in healthy older adults. A cross-correlation of the normalized angular speeds was performed and the experiment with 68 older adults was conducted. The results showed that the head, hip and ankle joints affected the transfer of angular sway with a relatively lower correlation and longer latency.