Development of Swimming Human Simulation Model Considering Rigid Body Dynamics and Unsteady Fluid Force for Whole Body

Omoda

2011

JFST

Self Cite

The objective of this study was to develop a simulation method to analyze the body behavior and to clarify the most stable body position while freefalling during a skydive. Using the simulation method, we conducted an optimizing calculation to maximize an objective function with respect to the stability in the freefall. It was found that the most stable position became an arched one. In order to clarify the reason why the most stable position became arched, optimization with respect to a simple shaped object consisting of 20 cylinders was conducted. Then the angle to maximize the restoring moment for each cylinder element was analytically calculated and compared with the optimized angle. From the results, we conclude that the most stable position becomes arched mainly since the restoring moment for each individual part is maximized at that angle. We also conclude that the magnitude of the arch in the most stable position is determined by the ratio of the normal and tangential drag coefficients.

Section: Calculation Methods Of the Fluid Force Acting On The Diver's mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

Development of a Simulation Method for Body Behavior during Skydiving and an Analysis of the Most Stable Position

Omoda

2011

JFST

Self Cite

“…2. These were measured from the video analysis and used for the simulation study by Nakashima et al (2007). From this figure, the phase differences between the hip, knee and ankle joints were found to have a simple relationship.…”

Section: Cpg Network To Generate a Flutter Kick Motionmentioning

confidence: 99%

CPG network to generate the swimming motion of the crawl stroke

Mechanical Engineering Journal

Fujita

Miyazawa

et al. 2017

Self Cite

The objective of this study was to propose a CPG network which can generate the swimming motion of the crawl stroke. First, the CPG network for legs performing a flutter kick was constructed by connecting the neural oscillators for the leg joints. The flutter kick motion was successfully generated by the proposed CPG network. The propulsion by the generated flutter kick motion was confirmed by the simulation of the swimming movement. Next, the CPG network for both the arms and legs were constructed, in which the neural oscillator for the arms initiated the trigger signal to start the prescribed stroke motion. By changing the intrinsic cycle of the neural oscillators for the legs, both six-and two-beat crawls could be realized. It was also found that a stable region with respect to the relationship between the intrinsic cycles of the neural oscillators for the arms and legs certainly existed for the six-beat crawl, although the intrinsic cycles of the arms were three times longer than those of the legs in this case. The propulsion by the generated swimming motion was confirmed by the simulation of the swimming movement both for the six-and two-beat crawls. Finally, the roll angle of the swimmer was fed back into the CPG network in order to restore the balance in the roll direction. Restoring the balance in the roll direction was successfully realized by the proposed feedback algorithm. The resultant motion showed a complicated behavior, such as skipping strokes.

“…The swimming motion of the breaststroke in a previous simulation study by Nakashima [13] was used for the present study. This motion was created for the swimming human simulation model "SWUM" [12], based on the motion of an actual competitive swimmer. SWUM is a simulation model for analyses of human swimming, in which a swimmer's body is represented as a series of 21 truncated elliptic cones, and the rigid body dynamics and unsteady fluid forces are considered.…”

Section: Creation Of Swimming Motionmentioning

confidence: 99%

“…First, it is expected that it will become an experimental platform for the research of human swimming. To date, many simulation studies about human swimming have been conducted [12][13][14][15]. Such simulation technique is very useful and powerful tool for analysis.…”

Section: Introductionmentioning

confidence: 99%

Realization and swimming performance of the breaststroke by a swimming humanoid robot

Kuwahara

2016

Robomech J

Self Cite

In order to clarify the mechanics of human swimming, a full-body swimming humanoid robot called "SWUMANOID" was developed as an experimental platform for research about human swimming. SWUMANOID had a detailed human body shape, created using three-dimensional scanning and printing equipment, and was developed as an experimental model substituting for human subjects. Not only the appearance but also the methodology to realize various swimming strokes was considered. In order to reproduce complicated swimming motions with high fidelity, 20 waterproof actuators were installed. The free swimming of the crawl stroke at a velocity of 0.24 m/s was realized in the previous study. However, it could not perform the breaststroke due to mechanical limitations. The objectives of this study were to realize the breaststroke for SWUMANOID by improving its lower limbs, and to investigate the swimming performance of the breaststroke experimentally. The lower body of SWUMANOID was fully redesigned, built, and connected to the upper body. The swimming motion of the breaststroke was created based on that of an actual swimmer. A free swimming experiment was conducted in a 25 m outdoor swimming pool. In addition, in order to discuss the experimental results in detail, the experiment was reproduced by the simulation. From the experiment, it was found that SWUMANOID could perform the breaststroke successfully. The swimming speed for the stroke cycle of 2.3 s was found to be 0.12 m/s. Since this swimming speed was considered low compared to that of the actual swimmer, the reason for the discrepancy was examined by simulation. From the simulation, it was found that one main reason for the low swimming speed was insufficient output power of the motors, especially for the knee and shoulder joints.