scholarly journals Flux-balance equations for linear momentum and center-of-mass position of self-gravitating post-Newtonian systems

2019 ◽  
Vol 36 (8) ◽  
pp. 085003 ◽  
Author(s):  
Luc Blanchet ◽  
Guillaume Faye
Keyword(s):  
Center Of Mass ◽  
Linear Momentum ◽  
Balance Equations ◽  
Flux Balance ◽  
Newtonian Systems ◽  
Mass Position

Measurement Method Research on Inertial Parameters of Motor Assembly

2013 ◽  
Vol 437 ◽  
pp. 663-668
Author(s):  
Ling Sun ◽  
Peng Yu ◽  
Tong Zhang
Keyword(s):  
Measurement Method ◽  
Center Of Mass ◽  
Moment Of Inertia ◽  
Balance Method ◽  
Test Error ◽  
Inertial Parameters ◽  
Drive Motor ◽  
Weight Method ◽  
Mass Position

Inertial parameters of the motor assembly include its mass, CM (center of mass) position, moment of inertia and product of inertia. Taking one vehicle drive motor as the research object, its mass and CM position are measured by using weight method and moment balance method respectively. Its moment of inertia and product of inertia are measured by using three-wire pendulum. On the basis of analyzing the test error, this paper proposed specific measures to reduce the test error.

Is the erect posture in microgravity based on the control of trunk orientation or center of mass position?

1997 ◽  
Vol 114 (2) ◽  
pp. 384-389 ◽  
Author(s):  
J. Massion ◽  
K. Popov ◽  
J.-C. Fabre ◽  
P. Rage ◽  
V. Gurfinkel
Keyword(s):  
Center Of Mass ◽  
Erect Posture ◽  
Trunk Orientation ◽  
Mass Position

scholarly journals The effect of head movement on the bounding gait of a quadruped robot with an active spine

2019 ◽  
Vol 11 (9) ◽  
pp. 168781401987618
Author(s):  
Dongliang Chen ◽  
Chen Gong ◽  
Fuze Xing ◽  
Changhe Zhou ◽  
Mengfei Qi ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Head Movement ◽  
Pitch Angle ◽  
Center Of Mass ◽  
Quadruped Robot ◽  
Head Motion ◽  
Common Phenomenon ◽  
Simulation And Experiment ◽  
Mass Position ◽  
Bounding Gait

It is a common phenomenon in the movement of the quadruped mammals accompanied with head swings. Inspired by this, this article attempts to add head motion to the bounding gait of a quadruped robot. According to the theoretical analysis, there are two main functions of the head. First, the head can realize the active control of the center of mass position of the robot, which is of great significance to the stable motion of the robot. Second, the swing of the head plays a role in regulating the pitch angle of the torso and improves the coordination and stability of the motion. A simplified quadruped robot model with a head and spine joint is established and analyzed theoretically. The regularity of head movement in periodic bounding gait is summarized. Through simulation and experiment, we confirm the two roles of the head in the bounding gait of a quadruped robot.

scholarly journals Association between Changes in Swimming Velocity, Vertical Center of Mass Position, and Projected Frontal Area during Maximal 200-m Front Crawl

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 60
Author(s):  
Sohei Washino ◽  
Akihiko Murai ◽  
Hirotoshi Mankyu ◽  
Yasuhide Yoshitake
Keyword(s):  
Inverse Kinematics ◽  
Center Of Mass ◽  
Three Dimensional ◽  
Frontal Area ◽  
Whole Body ◽  
Swimming Velocity ◽  
Front Crawl ◽  
Motion Data ◽  
Mass Position ◽  
Shape Data

We examined the association between changes in swimming velocity, vertical center of mass (CoM) position, and projected frontal area (PFA) during maximal 200-m front crawl. Three well-trained male swimmers performed a single maximal 200-m front crawl in an indoor 25-m pool. Three-dimensional (3D) shape data of the whole body were fitted to 3D motion data during swimming by using inverse kinematics computation to estimate PFA accurately. Swimming velocity decreased, the vertical CoM position was lowered, and PFA increased with swimming distance. There were significant correlations between swimming velocity and vertical CoM position (|r| = 0.797–0.982) and between swimming velocity and PFA (|r| = 0.716–0.884) for each swimmer. These results suggest that descent of the swimmer’s body and increasing PFA with swimming distance are associated with decreasing swimming velocity, although the causal factor remains unclear.

The Optimality of the Handbrake Cornering Technique

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Davide Tavernini ◽  
Efstathios Velenis ◽  
Roberto Lot ◽  
Matteo Massaro
Keyword(s):  
Driver Behavior ◽  
Center Of Mass ◽  
Optimal Solution ◽  
Road Surface ◽  
Aggressive Driving ◽  
Data Set ◽  
Control Techniques ◽  
Vehicle Data ◽  
Lateral Space ◽  
Mass Position

The paper investigates the optimality of the handbrake cornering, a strategy widespread among rally drivers. Nonlinear optimal control techniques are used to mimic real driver behavior. A proper yet simple cost function is devised to induce the virtual optimal driver to control the car at its physical limits while using the handbrake technique. The optimal solution is validated against experimental data by a professional rally driver performing the handbrake technique on a loose off-road surface. The effects of road surface, inertial properties, center of mass position, and friction coefficient are analyzed to highlight that the optimality of the maneuver does not depend on the particular vehicle data set used. It turns out that the handbrake maneuvering corresponds to the minimum time and minimum (lateral) space strategy on a tight hairpin corner. The results contribute to the understanding of one of the so-called aggressive driving techniques.

scholarly journals Similar sensorimotor transformations control balance during standing and walking

2021 ◽  
Vol 17 (6) ◽  
pp. e1008369
Author(s):  
Maarten Afschrift ◽  
Friedl De Groote ◽  
Ilse Jonkers
Keyword(s):  
Gait Cycle ◽  
Walking Speed ◽  
Balance Control ◽  
Center Of Mass ◽  
Linear Feedback ◽  
Sensorimotor Transformations ◽  
Robotic Devices ◽  
Walking Balance ◽  
Mass Position ◽  
Task Level

Standing and walking balance control in humans relies on the transformation of sensory information to motor commands that drive muscles. Here, we evaluated whether sensorimotor transformations underlying walking balance control can be described by task-level center of mass kinematics feedback similar to standing balance control. We found that delayed linear feedback of center of mass position and velocity, but not delayed linear feedback from ankle angles and angular velocities, can explain reactive ankle muscle activity and joint moments in response to perturbations of walking across protocols (discrete and continuous platform translations and discrete pelvis pushes). Feedback gains were modulated during the gait cycle and decreased with walking speed. Our results thus suggest that similar task-level variables, i.e. center of mass position and velocity, are controlled across standing and walking but that feedback gains are modulated during gait to accommodate changes in body configuration during the gait cycle and in stability with walking speed. These findings have important implications for modelling the neuromechanics of human balance control and for biomimetic control of wearable robotic devices. The feedback mechanisms we identified can be used to extend the current neuromechanical models that lack balance control mechanisms for the ankle joint. When using these models in the control of wearable robotic devices, we believe that this will facilitate shared control of balance between the user and the robotic device.

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