Manipulation Planning for Large Objects through Pivoting, Tumbling, and Regrasping

Robotic manipulation of a bulky object is challenging due to the limited kinematics and payload of the manipulator. In this study, a robot realizes the manipulation of general-shaped bulky objects utilizing the contact with the environment. We propose a hierarchical manipulation planner that effectively combined three manipulation styles, namely, pivoting, tumbling, and regrasping. In our proposed method, we first generate a set of superimposed planar segments on the object surface to obtain an object pose in stable contact with the table, and a set of points on the object surface for the end-effectors (EEFs) of a dual-arm manipulator to stably grasp the object. Object manipulation can be realized by solving a graph, considering the kinematic constraints of pivoting and tumbling. For pivoting, we consider two supporting styles: stable support (SP) and unstable support (USP). Our proposed method manipulates large and heavy objects by selectively using the two different support styles of pivoting and tumbling according to the conditions on the table area. In addition, it can effectively avoid the limitation arising due to the arm kinematics by regrasping the object. We experimentally demonstrate that a dual-arm manipulator can move an object from the initial to goal position within a limited area on the table, avoiding obstacles placed on the table.

Physical activity in stroke patients: A scoping review

Stroke is the second leading cause of disability and death worldwide with 5.9 million deaths annually. Stroke can be followed by various clinical problems. Impaired motoric function of the extremities is the most severe post stroke disorder experienced and impacts on limitations of daily activities. The main treatment is by doing regular physical activity exercises. This review was conducted to identify physical activities that can be performed by stroke patients. This scoping review was compiled using Arksey and O'Malley's five-stage framework. A total of three databases (i.e., Pubmed, Proquest, and DOAJ) was searched with relevant keyword "physical activity OR exercise AND stroke". The articles selected are published in the last 5 years, in English, and in full text. The literature search retrieved 164 studies to be screened based on the exclusion-inclusion criteria which finally resulted in the 11 studies included in the review. The remaining 11 studies were fully read and data were extracted regarding the type of physical activity, goals, settings and outcomes. Qualitative (i.e., theme analysis) methods have been used to synthesis the data. Based on the results of the review, there are several physical activities that stroke patients can do, such as progressive resistance and balance (PRB) exercises, locomotors exercises: (walking on a treadmill with body weight support and walking on the ground), selective movements of the upper and lower trunk body in the Supine and sit using a stable support / pad or unstable support (Swiss ball), core stability training, aerobic (AT) and resistance training (RT), aerobic training, walking exercises, and task-oriented training. Several physical exercises have been identified where each of these exercises has a purpose and benefit in the recovery of physical functional stroke patients. Physical activity should be done regularly and take into account the duration, intensity, and frequency of the exercise based on patient’s ability and stamina.

The effect of Estonian folk dance practice on static balance performance in young females

The aim of the present study was to establish the changes that occur in dancers’ static body balance indicators during rest, in case of interfering factors and in stress condition. The sample consisted of 14 advanced female folk dancers at the age of 16–20 years. The participants’ static body balance was measured at the beginning (in the autumn) and at the end (in the spring) of the eight-month dancing period. Static body balance indicators were registered on a dynamographic platform within 30 seconds, standing on bipedal on stable and unstable support surface in eyes-open (EO) and eyes-closed (EC) conditions. The Flamingo test balance control, the balance control after spinning around and jumping tests were conducted only in EO condition. The following parameters were registered: the movements of the centre of pressure (CoP) in the anterior-posterior (AP) and medio-lateral (ML) dimensions; the length, speed and area of the trajectory. According to the study, folk dancers’ CoP movements in the AP and ML dimensions, measured in different conditions (EO, EC), on stable and unstable support surface, did not change significantly after the eight-month dancing practice. The young folk dancers’ static body balance, assessed by CoP movement trajectory, speed and area, improved considerably over the eight-month training period. Flamingo test results indicate that practising folk dance develops the young female folk dancers’ right and left side static stability equally. In the context of Estonian folk dance practice, including preparation for performing at dance festival, the young female folk dancers’ balance performance improved both in vestibular instability (spins, standing on unstable support surface and in EO condition) and fatigue (jumping test) conditions.

Impairments of Postural Balance in Surgically Treated Lumbar Disc Herniation Patients

Reports on body sway control following microdiscectomy lack reports on side-specific balance deficits as well as the effects of trunk balance control deficits on body sway during upright stances. About 3 weeks post microdiscectomy, the body sway of 27 patients and 25 controls was measured while standing in an upright quiet stance with feet positioned parallel on an unstable support surface, a tandem stance with the involved leg positioned in front or at the back, a single-leg stance with both legs, and sitting on an unstable surface. Velocity, average amplitude, and frequency-direction–specific parameters were analyzed from the center of pressure movement, measured by the force plate. Statistically significant differences between the 2 groups were observed for the medial–lateral body sway frequency in parallel stance on a stable and unstable support surface and for the sitting balance task in medial-lateral body sway parameters. Medium to high correlations were observed between body sway during sitting and the parallel stance, as well as between the tandem and single-legged stances. Following microdiscectomy, deficits in postural balance were side specific, as expected by the nature of the pathology. In addition, the results of this study confirmed the connection between proximal balance control deficits and balance during upright quiet balance tasks.