Estimation of the influence of the design of school backpacks to posture regulation in children with different posture conditions

There was performed the study of the characteristics of the regulation of vertical posture in 42 children of 8-10 years old using school bags of different designs. According to medical examination 25 children have normal posture and 17 children had kyphotic one. The stability of the posture was estimated according to the average variance and the average velocity of the total center of gravity of the body, the area of the ellipse, and the quality of the equilibrium function with computer stabilography. Three models of school bags were used - with traditional, ergonomic and orthopedic back support. Vertical posture stability for children with impaired posture without school bag and when used with traditional and ergonomic back were significantly lower in comparison with children with normal posture. When the orthopedic back was used the stability impairment of the vertical posture in children with kyphotic posture was not observed. It is concluded that for the prevention of spinal deformity for students with kyphotic posture orthopedic school bags should be used.

Control algorithms for the emergence of self-organized behaviours in swarms of differential-traction wheeled mobile robots

This article proposes three control algorithms for the emergence of self-organized behaviours, including aggregation, flocking and rendezvous, in swarm robotics systems. The proposed control algorithms are based on a local polar coordinates’ control law available in the literature for posture regulation; this law is adapted to work in a self-organized robotic swarm using distance and bearing as coupling information. Therefore, the robots only need to know the radial distance and orientation to the goal; additionally, the three algorithms are based on self-organization, eliminating the need for a preset coupling topology among the robots. In particular, the flocking algorithm has a first stage for topology creation, while the rendezvous and aggregation algorithms change the topology on every iteration depending on the local interactions of the robots. The effectiveness of the algorithms was evaluated through numerical simulations of swarms of up to 100 differential traction wheeled mobile robots.

Nonholonomic virtual constraints and gait optimization for robust walking control

A key challenge in robotic bipedal locomotion is the design of feedback controllers that function well in the presence of uncertainty, in both the robot and its environment. This paper addresses the design of feedback controllers and periodic gaits that function well in the presence of modest terrain variation, without over-reliance on perception and a priori knowledge of the environment. Model-based design methods are introduced and subsequently validated in simulation and experiment on MARLO, an underactuated three-dimensional bipedal robot that is of roughly human size and is equipped with an inertial measurement unit and joint encoders. Innovations include an optimization method that accounts for multiple types of disturbances and a feedback control design that enables continuous velocity-based posture regulation via nonholonomic virtual constraints. Using a single continuously defined controller taken directly from optimization, MARLO traverses sloped sidewalks and parking lots, terrain covered with randomly thrown boards, and grass fields, all while maintaining average walking speeds between 0.9 and 0.98 m/s and setting a new precedent for walking efficiency in realistic environments.

Stability of equilibrium in upright stance and voluntary motion control in athletes-shooters in the process of ready position and target shooting

Purpose: consists in studying the relationships between the system of equilibrium regulation in upright stance and voluntary motion control in athletes-shooters during ready position and target shooting. Material: 19 highly skilled athletes specialized in pistol shooting were studied. Physiological and biomechanical characteristics of posture and voluntary motions were assessed by methods of stabilography, electromyography and tremorometry; besides, accuracy of target shooting was registered. Results: high degree of shooting accuracy dependence on posture somatic parameters has been revealed, of which the greatest impact upon the result is exerted by low-frequency vibrations of the body general centre of mass, subjected to voluntary control. Prognostic models of shooting accuracy dependence upon the character of posture regulation during ready position and the shot have been developed. Conclusions: obtained results reveal the mechanisms of functioning and interacting of two systems of management - posture and voluntary motion. Elaborated regression models permit to model and predict posture stability and shooting accuracy during ready position and the shot.