Wrist Position Sense in Two Dimensions: Between-Hand Symmetry and Anisotropic Accuracy Across the Space

A deep investigation of proprioceptive processes is necessary to understand the relationship between sensory afferent inputs and motor outcomes. In this work, we investigate whether and how perception of wrist position is influenced by the direction along which the movement occurs. Most previous studies have tested Joint Position Sense (JPS) through 1 degree of freedom (DoF) wrist movements, such as flexion/extension (FE) or radial/ulnar deviation (RUD). However, the wrist joint has 3-DoF and many activities of daily living produce combined movements, requiring at least 2-DoF wrist coordination. For this reason, in this study, target positions involved movement directions that combined wrist flexion or extension with radial or ulnar deviation. The chosen task was a robot-aided Joint Position Matching (JPM), in which blindfolded participants actively reproduced a previously passively assumed target joint configuration. The JPM performance of 20 healthy participants was quantified through measures of accuracy and precision, in terms of both perceived target direction and distance along each direction of movement. Twelve different directions of movement were selected and both hands tested. The left and right hand led to comparable results, both target extents and directions were differently perceived according to the target direction on the FE/RUD space. Moreover, during 2-DoF combined movements, subjects’ perception of directions was impaired when compared to 1-DoF target movements. In summary, our results showed that human perception of wrist position on the FE/RUD space is symmetric between hands but not isotropic among movement directions.

Incremental forming using KUKA KR210-2 industrial robot - research regarding design rules and process modelling

Incremental sheet forming (ISF) process show a great potential in the manufacturing of small series production or prototype development parts. One of the sheet metal forming process, where the contact between punch and metal sheet is in a single point, is known as single point incremental forming (SPIF). The part is manufacture with a simple tool, known as punch, that performs a series of combined movements on the vertically and horizontally directions. The paper introduces a study regarding the design rules and process modelling of this unconventional process, by means of a KUKA KR210-2 industrial robot as technological equipment able to control the correlated movement of the punch. Supplementary, the design of the experimental layout, the process simulations and the singularity problems are considered.

A Complementary Filter Design on SE(3) to Identify Micro-Motions during 3D Motion Tracking

In 3D motion capture, multiple methods have been developed in order to optimize the quality of the captured data. While certain technologies, such as inertial measurement units (IMU), are mostly suitable for 3D orientation estimation at relatively high frequencies, other technologies, such as marker-based motion capture, are more suitable for 3D position estimations at a lower frequency range. In this work, we introduce a complementary filter that complements 3D motion capture data with high-frequency acceleration signals from an IMU. While the local optimization reduces the error of the motion tracking, the additional accelerations can help to detect micro-motions that are useful when dealing with high-frequency human motions or robotic applications. The combination of high-frequency accelerometers improves the accuracy of the data and helps to overcome limitations in motion capture when micro-motions are not traceable with 3D motion tracking system. In our experimental evaluation, we demonstrate the improvements of the motion capture results during translational, rotational, and combined movements.

Effects of Daily Activities and Position on Kinematics and Contact Mechanics of Dual Mobility Hip Implant

Dual mobility hip implants have been widely introduced to overcome dislocation in recent years. However, the potential influence of different gaits on kinematics and contact mechanics for dual mobility hip implants is still unclear. Furthermore, a large range of motion coupling with the implant position, especially high inclination or anteversion angle, may result in poor kinematics and contact mechanics. A previously developed dynamic finite element method was adopted in this study to examine the kinematics and corresponding stability of dual mobility hip implants under different gaits coupling with different inclinations or anteversion angles. The results showed only inner relative sliding under knee-bending for dual mobility hip implants under moderate inclination and anteversion angles, whereas an anteversion angle of 25° induced both impingement and consequent relative sliding of the outer articulation. However, the impingement (between the stem neck and the liner inner rim) indeed happened under stair-climbing and sitting-down/stand-up as well as combined movements when inclination and anteversion angles were set as 45° and 0°, respectively, and this finally led to relative sliding at the outer articulation. A high inclination angle did not worsen both the impingement and related outer sliding compared to modest inclination and anteversion angles of the liner, but a high anteversion angle prolonged the period of both the impingement and the outer relative sliding. The extreme motions and high anteversion angles are hardly inevitable, and they indeed lead to motions at both articulations for dual mobility hip implants.

Creating cartoons to represent habitual leg movements

Many people have a habit of moving their legs and believe that this behavior is due to the restless legs syndrome (RLS), a highly prevalent neurological condition that greatly impairs the quality of life of affected individuals. This behavioral pattern, characterized by the habit of moving one’s legs and feet, may be an important confounding factor in the diagnosis of RLS. Objective: To describe the main movements associated with this benign behavioral state to characterize a possible clinical condition that can contribute to the differential diagnosis of RLS. Methods: Experienced sleep specialists, who primarily see RLS patients listed the most frequent movements people without RLS report while describing their suspected RLS. We first compiled a list of the lower-limb movements described by the specialists. Then, one of the authors (KC) carried out all movements of the list on camera to obtain a video footage. This footage was sent to one of the authors, EPC, who, alongside a group of students, drew graphic representations (cartoons) of the recorded movements. Results: The panel of sleep experts described 13 leg movements commonly reported by their patients. The experts reported 11 simple movements and two combined movements. Conclusion: In this study we developed an instrument that allows us to oppose and distinguish a pathological condition (RLS) from a behavioral phenomenon. This state of behavioral leg fidgeting needs to be better characterized and may eventually be recognized as a clinical entity per se.

Analysis of the pedestrian traffic in transport nodes in Radom

The efficient functioning of the transport system in each area requires that account be taken of the fact that each journey consists of a chain of elementary movements on foot or by means of trans­port. The construction of an effective public transport system is one of the methods to reduce traffic congestion, especially in city centres. The inter-change synchronization is the way to increase the efficiency of public transport. The purpose of the paper is to present the results of research on the intensity of pedestrian traffic at interchanges as a function of time in the city of Radom. Pedestrian movements play an important role not only in the vicinity of transport nodes. Their production and quality also determine the assessment of these movements as one of the stages of production of combined movements. The tendency to pedestrian travel (or lack of it) also affects public and individual transport journeys. Based on the survey conducted in households, the structure of movement (size and motivations) of the inhabitants of Radom is given.

Cahokia’s Beginnings

The combined movements of local and foreign people from pre-Mississippian villages and hamlets into mound centers and out to isolated farmsteads resulted in the creation of Cahokia at AD 1050 as an urban space and the center of a regionally integrated polity. Through these movements, landscapes were redefined and identities and power relations among local and foreign groups were negotiated. It is asserted that such movements interfered with local sources of power while a sense of shared identity was fostered through participation in communal events. Through analyses of site layout, occupational history, and material culture, the historical effects of these movements are traced.