Linear Relationships Among the Hand and Clubhead Motion Characteristics in Golf Driving in Skilled Male Golfers

The purpose of this study was to investigate the linear relationships among the hand/clubhead motion characteristics in golf driving in skilled male golfers (n = 66; handicap ≤ 3). The hand motion plane (HMP) and functional swing plane (FSP) angles, the HMP–FSP angle gaps, the planarity characteristics of the off-plane motion of the clubhead, and the attack angles were computed from the drives captured by an optical motion capture system. The HMP angles were identified as the key variables, as the HMP and FSP angles were intercorrelated, but the plane angle gaps, the planarity bias, and the attack angles showed correlations to the HMP angles primarily. Three main swing pattern clusters were identified. The parallel HMP–FSP alignment pattern with a small direction gap was associated with neutral planarity and planar swing pattern. The inward alignment pattern with a large inward direction gap was characterized by flat planes, follow-through-centric planarity, spiral swing pattern, and inward/downward impact. The outward alignment pattern with a large outward direction gap was associated with steep planes, downswing-centric planarity, reverse spiral swing, and outward/upward impact. The findings suggest that practical drills targeting the hand motion pattern can be effective in holistically reprogramming the swing pattern.

Sensorimotor impairment and haptic support in microgravity

Future space missions envisage human operators teleoperating robotic systems from orbital spacecraft. A potential risk for such missions is the observation that sensorimotor performance deteriorates during spaceflight. This article describes an experiment on sensorimotor performance in two-dimensional manual tracking during different stages of a space mission. We investigated whether there are optimal haptic settings of the human-machine interface for microgravity conditions. Two empirical studies using the same task paradigm with a force feedback joystick with different haptic settings (no haptics, four spring stiffnesses, two motion dampings, three masses) are presented in this paper. (1) A terrestrial control study ($$N=20$$ N = 20 subjects) with five experimental sessions to explore potential learning effects and interactions with haptic settings. (2) A space experiment ($$N=3$$ N = 3 cosmonauts) with a pre-mission, three mission sessions on board the ISS (2, 4, and 6 weeks in space), and a post-mission session. Results provide evidence that distorted proprioception significantly affects motion smoothness in the early phase of adaptation to microgravity, while the magnitude of this effect was moderated by cosmonauts’ sensorimotor capabilities. Moreover, this sensorimotor impairment can be compensated by providing subtle haptic cues. Specifically, low damping improved tracking smoothness for both motion directions (sagittal and transverse motion plane) and low stiffness improved performance in the transverse motion plane.

Kinematic Differences between Two Types of Forward Elevations of the Shoulder Joint: Flexion and Reaching Elevation

Background: Extension of the elbow joint is maintained during shoulder flexion. In contrast, the arm starts from the flexed position of the elbow joint and the joint gradually extends during reaching elevation. Objectives: This study aimed to compare the kinematic elements and electromyographic (EMG) activities of the rotator cuff muscles between flexion and reaching elevation. Methods: The study included 10 healthy young men. (average age, 21.5 ± 3.4 years), and measurements were performed on their dominant arms. A three-dimensional motion analyzer was used to record the following elements during shoulder flexion and reaching elevation: the angles of glenohumeral joint elevation and scapular upward rotation, scapulohumeral rhythm, external rotation of the humerus, and glenohumeral plane shifting from the coronal plane. The EMG activities in the supraspinatus, infraspinatus, subscapularis, and teres minor were recorded simultaneously. Results: The plane of reaching elevation was retained at 60° from the coronal plane. The glenohumeral planes (P < 0 .01) and the external rotation angles of the humerus below 90° of elevation (P < 0.05) were significantly different between both the motions. The EMG activities in the supraspinatus (P < .01), infraspinatus (P < 0.05), and teres minor (P < 0.01) were significantly lower while reaching elevation than those during flexion. Conclusion: The motion plane at 60° from the coronal plane, movement of the humeral external rotation, and EMG activities of the rotator cuff muscles were different during reaching elevation and shoulder flexion.

Modeling and Analysis of a Planar Soft Panel Continuum Mechanism

Continuum mechanisms have drawn wide attention to scholars due to their salient advantages including compliance and dexterity. In this paper, a planar continuum mechanism made of soft panels is proposed. This mechanism has a reduced degree-of-freedom (DOF) compared with some existing continuum mechanisms capable of 3D motion. However, it can meet some application requirements in the field of robot and aerospace due to its characteristics of small stiffness in the motion plane and large stiffness perpendicular to the motion plane. Besides, a combined kinematics and statics modeling approach is presented for this mechanism by using the classical beam theory and a constrained optimization method. In order to ensure the model accuracy, a hybrid approach is proposed to consider gravity depending on the deformation under study. By comparing our results with those from the commonly used constant-curvature method, it is shown that our model is more accurate in predicting the deformation shapes.

Designing a Swarm Control Algorithm for a Group of Robots in a Persistently Disturbed Environment

The paper describes the development of a software simulation package in the MATLAB 2017b environment for modelling the problem of swarm control of a group of robots moving a platform at a preset velocity to a certain target region of the motion plane when the environment is persistently disturbed. We present simulation results for solving the problem for groups of two and four robots. We plan to use the software package as a basis for implementing more complex swarm control problems, such as target interception by a group of small smart weapons. The main feature of swarm control is minimum amount of information used. This approach improves the survivability of the system as a whole. Group decision-making time virtually does not depend on the number of robots in the swarm. Each robot changes those parameters of the platform that are also affected by the actions of other robots. Each robot in the swarm uses measurements to arrive at optimum control in limited information conditions relative to the system configuration and target requirements, which is what ensures completion of the task posed. Each robot operates independently from others.

Optimizing service life of conveyor belts while transporting bulk load

The paper considers problems concerning optimization of service life of a conveyor belt in terms of its bulk material loading. Statement of the problem of belt life optimization is in the determining minimum of difference between squared velocity of a conveyor belt and projection of horizontal component of the load velocity when it contacts a belt onto the belt motion plane. The problem was solved numerically taking into consideration the objective function, varied parameters, and their limitation. Cases of direct-flow loading and loading with the help of special devices with straight and curved trough profiles have been analyzed. Regularities of changes in the belt service life due to significant factors in terms of direct-flow loading and loading with special device have been obtained to perform comparative analysis of different variants in terms of similar value of the objective function. The variants with maximum belt life and minimum objective function have been selected. For short conveyors, in terms of direct-flow loading, belt life decreases by 1.5–2.0 times comparing to the use of a loading device, and in terms of long conveyors, it decreases by 5–6 times, if value of the objective function is 0.5–1.0 m2/s2.