scholarly journals Experimental research and floating gait planning of crablike robot

2020 ◽  
Vol 12 (2) ◽  
pp. 168781402090485
Author(s):  
Hai-Long Wang ◽  
Xing-Ya Yan ◽  
Gang Wang ◽  
Qi-Feng Zhang ◽  
Qi-Yan Tian ◽  
...  
Keyword(s):  
Water Resistance ◽  
Swimming Performance ◽  
Hydrodynamic Performance ◽  
Portunus Trituberculatus ◽  
Swimming Velocity ◽  
Force Analysis ◽  
Gait Planning ◽  
Propulsion Mechanism ◽  
Underwater Propulsion ◽  
Structure Scheme

In order to improve the swimming performance of a paddle-propelled crablike robot, the sequence and parameters of swimming gait are planned according to the bionic swimming mechanism. Based on the bionic prototype of Portunus trituberculatus, the structure scheme of a leg–paddle hybrid driven robot is proposed with the functions of walking on land, crawling on seabed, and swimming underwater. By analyzing the underwater propulsion mechanism of single paddle and hydrodynamic performance of double paddles cooperatively propulsion, four direct swimming gaits are planned and the corresponding attitude changes are theoretically analyzed. Then, the numerical simulation and direct swimming experiments are carried out to verify the effectiveness of proposed gaits and correctness of force analysis. In alternate swimming gait of lift-based mode, the robot swims forward in a rolling attitude, with an advantage of the minimum water resistance and the optimum swimming velocity and efficiency. The influence of flapping frequency and relative phases of paddles on the swimming velocity shows the trend of raise first and then fall.

Adaptive obstacle climbing and hydrodynamic performance analyses of the amphibious robot with wheels and flexible undulating fins

2022 ◽  
pp. 095440622110590
Author(s):  
Qian Yin ◽  
Minghai Xia ◽  
Zirong Luo ◽  
Jianzhong Shang
Keyword(s):  
Swimming Performance ◽  
Industrial Applications ◽  
Hydrodynamic Performance ◽  
Hydrodynamic Characteristics ◽  
Experimental Measurements ◽  
Underwater Propulsion ◽  
Performance Analyses ◽  
The Difference ◽  
Amphibious Robot ◽  
Undulating Fin

In this paper, an amphibious robot with flexible undulating fins and self-adaptive climbing wheels are proposed for satisfying the needs of industrial applications. The structure of the climbing mechanism and undulating fin are firstly designed. Then, the adaptive obstacle climbing and the hydrodynamic characteristics are investigated through numerical simulations by using the Adams and Fluent, respectively. Finally, the experimental measurements of the land walking and underwater propulsion are studied. The numerical results illustrate that the amphibious robot could climb the vertical obstacle adaptively. In the underwater marching pattern, the underwater velocity could reach 1 m/s. In the rotating and yawing patterns, the angular velocity increases to the certain value while the rotating angle keeps increasing. The robot moves forward and turns around with the difference frequency of the undulating fins. The underwater propulsion and land-walking experiments show good swimming performance and the obstacle crossing ability of the amphibious robot, respectively, which verify the numerical simulation.

Relationships Between Propulsion and Anthropometry in Paralympic Swimmers

2015 ◽  
Vol 10 (8) ◽  
pp. 978-985 ◽  
Author(s):  
Andrew A. Dingley ◽  
David B. Pyne ◽  
Brendan Burkett
Keyword(s):  
Surface Area ◽  
Muscle Mass ◽  
Physical Disability ◽  
Swimming Performance ◽  
Upper Body ◽  
Swimming Velocity ◽  
Frontal Surface ◽  
Anthropometric Measures ◽  
Arm Span ◽  
Upper Body Power

Purpose:To characterize relationships between propulsion, anthropometry, and performance in Paralympic swimming.Methods:A cross-sectional study of swimmers (13 male, 15 female) age 20.5 ± 4.4 y was conducted. Subject locomotor categorizations were no physical disability (n = 8, classes S13–S14) and low-severity (n = 11, classes S9–S10) or midseverity disability (n = 9, classes S6–S8). Full anthropometric profiles estimated muscle mass and body fat, a bilateral swim-bench ergometer quantified upper-body power production, and 100-m time trials quantified swimming performance.Results:Correlations between ergometer mean power and swimming performance increased with degree of physical disability (low-severity male r = .65, ±0.56, and female r = .68, ±0.64; midseverity, r = .87, ±0.41, and r = .79, ±0.75). The female midseverity group showed nearperfect (positive) relationships for taller swimmers’ (with a greater muscle mass and longer arm span) swimming faster, while for female no- and low-severity-disability groups, greater muscle mass was associated with slower velocity (r = .78, ±0.43, and r = .65, ±0.66). This was supported with lighter females (with less frontal surface area) in the low-severity group being faster (r = .94, ±0.24). In a gender contrast, low-severity males with less muscle mass (r = -.64, ±0.56), high skinfolds (r = .78, ±0.43), a longer arm span (r = .58, ±0.60) or smaller frontal surface area (r = -.93, ±0.19) were detrimental to swimming-velocity production.Conclusion:Low-severity male and midseverity female Paralympic swimmers should be encouraged to develop muscle mass and upper-body power to enhance swimming performance. The generalized anthropometric measures appear to be a secondary consideration for coaches.

Interactive effects of salinity on metabolic rate, activity, growth and osmoregulation in the euryhaline milkfish (Chanos chanos)

1998 ◽  
Vol 201 (24) ◽  
pp. 3355-3366
Author(s):  
C Swanson
Keyword(s):  
Metabolic Rate ◽  
High Salinity ◽  
Swimming Performance ◽  
Interactive Effects ◽  
Routine Activity ◽  
Swimming Velocity ◽  
Activity Levels ◽  
Salinity Adaptation ◽  
Chanos Chanos ◽  
Wide Range

The euryhaline milkfish (Chanos chanos) is an excellent subject for studies of the physiological and behavioral processes involved in salinity adaptation. In this study, energy partitioning for metabolism, activity and growth, maximal activity performance and blood osmotic concentrations were assessed at two activity levels in juvenile milkfish fed equal rations and maintained at a relatively constant temperature (262 C) and at salinities(15, 35 and 55 ?) that represented a wide range of osmoregulatory challenges. Changes in the measured parameters were not consistently related to the magnitude of the trans-integumentary osmotic gradients. Routine oxygen consumption rates were high in 35 ? salinity (mean 1 s.e.m. 1678 mg O2 kg-1 h-1) and comparably low in 15 and 55 ? salinity (1336 and 1273 mg O2 kg-1 h-1, respectively). Routine activity levels (relative swimming velocity) were highest in 35 ? salinity (0. 960.04 L s-1), where L is standard length, intermediate in 15 ? salinity (0.770.03 L s-1) and lowest in 55 ? salinity (0.670.03 L s-1). Growth was significantly higher in 55 ? salinity (3.40.2 % increase in wet body mass per day) than in 35 ?salinity (2.40.2 % increase per day) and intermediate in 15 ? salinity(2.90.5 % increase per day). Maximum swimming velocities decreased with increases in salinity, from 9.90.7 L s-1 in 15 ? salinity to 6.60. 5 L s-1 in 55 ? salinity. Sustained swimming activity above routine levels for 2 h resulted in an increase in blood osmotic concentrations in milkfish in 55 ?salinity, but osmoregulation was re-established during the second 2 h of activity. Thus, patterns of variation in metabolic rate and growth were largely parallel to variations in routine activity although, comparing 15 and 55 ? salinity, elevated maintenance costs for osmoregulation at the high salinity were detectable. Reduced osmoregulatory abilities and reductions in maximal swimming performance suggest that high salinity may constrain activity. The results demonstrate that investigations of salinity adaptation in euryhaline fishes should take into account the interactive effects of salinity on physiology and behavior.

Sea lice infection of juvenile pink salmon (Oncorhynchus gorbuscha): effects on swimming performance and postexercise ion balance

2011 ◽  
Vol 68 (2) ◽  
pp. 241-249 ◽  
Author(s):  
L. Nendick ◽  
M. Sackville ◽  
S. Tang ◽  
C. J. Brauner ◽  
A. P. Farrell
Keyword(s):  
Swimming Performance ◽  
Life Stage ◽  
Pink Salmon ◽  
Infection Intensity ◽  
Sea Lice ◽  
Whole Body ◽  
Oncorhynchus Gorbuscha ◽  
Swimming Velocity ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Average Body Mass

Sea lice ( Lepeophtheirus salmonis ) infection negatively affected swimming performance and postswim body ion concentrations of juvenile pink salmon ( Oncorhynchus gorbuscha ) at a 0.34 g average body mass but not at 1.1 g. Maximum swimming velocity (Umax) was measured on over 350 individual pink salmon (0.2–3.0 g), two-thirds of which had a sea lice infection varying in intensity (one to three sea lice per fish) and life stage (chalimus 1 to preadult). For fish averaging 0.34 g (caught in a nearby river free of sea lice and transferred to seawater before being experimentally infected), the significant reduction in Umax was dependent on sea lice life stage, not intensity, and Umax decreased only after the chalimus 2 life stage. Experimental infections also significantly elevated postswim whole body concentrations of sodium (by 23%–28%) and chloride (by 22%–32%), but independent of sea lice developmental stage or infection intensity. For fish averaging 1.1 g (captured in seawater with existing sea lice), the presence of sea lice had no significant effect on either Umax or postswim whole body ions. Thus, a single L. salmonis impacted swimming performance and postswim whole body ions of only the smallest pink salmon and with a sea louse stage of chalimus 3 or greater.

scholarly journals The Influence of Anthropometric, Kinematic and Energetic Variables and Gender on Swimming Performance in Youth Athletes

2013 ◽  
Vol 39 (1) ◽  
pp. 203-211 ◽  
Author(s):  
Jorge E Morais ◽  
Nuno D Garrido ◽  
Mário C Marques ◽  
António J Silva ◽  
Daniel A Marinho ◽  
...  
Keyword(s):  
Surface Area ◽  
Swimming Performance ◽  
Gender Effect ◽  
Swimming Velocity ◽  
Stroke Index ◽  
Propulsive Efficiency ◽  
Stroke Frequency ◽  
Self Evaluation ◽  
Speed Fluctuation ◽  
And Gender

Abstract The aim of this study was to assess the: (i) gender; (ii) performance and; (iii) gender versus performance interactions in young swimmers’ anthropometric, kinematic and energetic variables. One hundred and thirty six young swimmers (62 boys: 12.76 ± 0.72 years old at Tanner stages 1-2 by self-evaluation; and 64 girls: 11.89 ± 0.93 years old at Tanner stages 1-2 by self-evaluation) were evaluated. Performance, anthropometrics, kinematics and energetic variables were selected. There was a non-significant gender effect on performance, body mass, height, arm span, trunk transverse surface area, stroke length, speed fluctuation, swimming velocity, propulsive efficiency, stroke index and critical velocity. A significant gender effect was found for foot surface area, hand surface area and stroke frequency. A significant sports level effect was verified for all variables, except for stroke frequency, speed fluctuation and propulsive efficiency. Overall, swimmers in quartile 1 (the ones with highest sports level) had higher anthropometric dimensions, better stroke mechanics and energetics. These traits decrease consistently throughout following quartiles up to the fourth one (i.e. swimmers with the lowest sports level). There was a non-significant interaction between gender and sports level for all variables. Our main conclusions were as follows: (i) there are non-significant differences in performance, anthropometrics, kinematics and energetics between boys and girls; (ii) swimmers with best performance are taller, have higher surface areas and better stroke mechanics; (iii) there are non-significant interactions between sports level and gender for anthropometrics, kinematics and energetics.

A PERFORMANCE PREDICTIVE MODEL FOR STEADY SWIMMING OF A FISH ROBOT

2011 ◽  
Vol 08 (01) ◽  
pp. 185-203 ◽  
Author(s):  
K. H. LOW ◽  
C. W. CHONG ◽  
CHUNLIN ZHOU ◽  
GERALD SEET
Keyword(s):  
Thrust Force ◽  
Swimming Performance ◽  
Empirical Method ◽  
Swimming Velocity ◽  
Underwater Robots ◽  
Swimming Mode ◽  
Reasonable Prediction ◽  
Dimensional Analysis Method ◽  
Semi Empirical ◽  
Analytical Approaches

Swimming performance is one of the primary concerns and applications to the underwater robots, such as thrust force relating to swimming velocity. As fish's swimming involves the kinematics of its own body and the hydrodynamic interaction with the surrounding fluid, it is difficult to formulate a precise mathematical model by purely analytical approaches. In order to avoid tedious parameter studies in evaluating its performance, this paper proposes a semi-empirical method to model the steady-state swimming performance of a BCF (body and/or caudal fin) biomimetic robotic robot. By using a dimensional analysis method, the semi-empirical model for predicting the thrust force generated by a BCF-oscillating swimming mode is derived. Thereafter, the swimming velocity prediction model is established based on the predictive thrust model together with the use of fundamental theory on drag force and the regression analysis on the experimental data. The model shows a reasonable prediction capability as the resultant predicted results are in good agreement with experiment data. Therefore, the proposed modeling method can be used for a quick prediction of the swimming performance in terms of thrust and velocity. The proposed methodology can be extended to other types of fish robots in real environment, by including changes to relevant parameters.

scholarly journals Biomechanical characterization of swimmers with physical disabilities

Motricidade ◽  
2018 ◽  
Vol 14 (4) ◽  
pp. 103-112 ◽  
Author(s):  
Valdir Junior ◽  
Alexandre Medeiros ◽  
Kelly Jesus ◽  
Nuno Domingos Garrido ◽  
Rui Corredeira ◽  
...  
Keyword(s):  
Swimming Performance ◽  
Velocity Variation ◽  
Swimming Velocity ◽  
Stroke Length ◽  
Stroke Frequency ◽  
Mean Values ◽  
Functional Classes ◽  
The Mean ◽  
Incremental Protocol

The evaluation of swimming technique is one of the main aspects to be considered in any training program, with biomechanics being an important source of knowledge. It was our objective to characterize the biomechanical parameters (SL and SF) relating them to the swimming velocity (v) at different intensities and to analyze within each swimming stroke cycle the intra-cyclic velocity variation (IVV) in a group of motor disabled swimmers. Eight disabled male swimmers (25.83 ± 2.93 years old, 72.45 ± 9.26 kg body mass and 1.79 ± 0.11 m of height) of the following functional classes: S6 (n = 1), S8 (n = 2) and S9 (n = 5) participated in this study. Swimmers were evaluated in the kinematic parameters v, stroke frequency (SF) and stroke length (SL) along with an incremental protocol of 6 x 200 m in the the crawl stroke. Data were registered in each step at the distances of 100 and 175 m. With increasing velocity, the mean values of SL decreased while the mean values of SF increased. To achieve higher swimming velocities, swimmers compensated the lack of the propulsive segment increasing SF to increase swimming speed. For the mean values of IVV at 100m distance, a decrease between the first and second levels, followed by a tendency to stabilize from the 2nd to the 6th level is presented. For the 175 m distance, there was a decrease in IVV with an increase in swimming velocity. Stroke frequency is directly related to the magnitude of IVV, which directly influences swimming performance.

scholarly journals Transfer of Dry-Land Resistance Training Modalities to Swimming Performance

2020 ◽  
Vol 74 (1) ◽  
pp. 195-203
Author(s):  
Jerzy Sadowski ◽  
Andrzej Mastalerz ◽  
Wilhelm Gromisz
Keyword(s):  
Resistance Training ◽  
Repeated Measures ◽  
Swimming Performance ◽  
Swimming Velocity ◽  
Training Experience ◽  
Dry Land ◽  
Significance Level ◽  
Training Interventions ◽  
And Control ◽  
Training Modalities

Abstract A great number of studies focusing on the effects of dry-land resistance training interventions on swimming performance remain inconclusive. It is suggested that transferability of dry-land strength gains to swimming performance appear when dry-land resistance training programs are swim-specific. The main aim of this study was to compare the effects of specific dry-land resistance training on an ergometer with traditional dry-land exercises, and to determine how much of the resistance training effects were transferred to specific swimming conditions. The study included a group of 26 youth competitive male swimmers (age 15.7 ± 0.5 years, height 174.6 ± 6.6 cm, weight 68.4 ± 8.2 kg, training experience 5.8±0.7 years) of regional level. They were randomly allocated to one of two groups: experimental (E) and control (T). Both groups were involved in a 12-week dry-land resistance training concentrated on increasing muscular strength and power output of the upper limbs. Group E used a specialized ergometer (JBA – Zbigniew Staniak), while group T performed traditional resistance exercises. The program consisted of 10 sets of 30 s of exercise with 30 s rest intervals between each set. A two-way repeated measures ANOVA with Tukey HSD post hoc comparisons was used to determine if any significant differences existed between training groups across pretest and posttest conditions. The significance level was set at p ≤ 0.05. Dry-land resistance training modalities were the only differences in training between both groups. Our findings show that rates of transfer are much higher in group E than in group T, which resulted in a significant increase in swimming velocity (by 4.32%, p<0.001; ES=1.23, and 2.78%, p<0.003, ES=0.31, respectively).

Intracyclic Variation of Force and Swimming Performance

2018 ◽  
Vol 13 (7) ◽  
pp. 897-902 ◽  
Author(s):  
Pedro G. Morouço ◽  
Tiago M. Barbosa ◽  
Raul Arellano ◽  
João P. Vilas-Boas
Keyword(s):  
Swimming Performance ◽  
Time Trial ◽  
Velocity Variation ◽  
Swimming Velocity ◽  
Stroke Rate ◽  
Free Swimming ◽  
Front Crawl ◽  
Continuous Application ◽  
High Level ◽  
Maximal Effort

Context: In front-crawl swimming, the upper limbs perform alternating movements with the aim of achieving a continuous application of force in the water, leading to lower intracyclic velocity variation (dv). This parameter has been identified as a crucial criterion for swimmers’ evaluation. Purpose: To examine the assessment of intracyclic force variation (dF) and to analyze its relationship with dv and swimming performance. Methods: A total of 22 high-level male swimmers performed a maximal-effort 50-m front-crawl time trial and a 30-s maximal-effort fully tethered swimming test, which were randomly assigned. Instantaneous velocity was obtained by a speedometer and force by a strain-gauge system. Results: Similarity was observed between the tests, with dF attaining much higher magnitudes than dv (P < .001; d = 8.89). There were no differences in stroke rate or in physiological responses between tethered and free swimming, with a high level of agreement for the stroke rate and blood lactate increase. Swimming velocity presented a strong negative linear relationship with dF (r = −.826, P < .001) and a moderate negative nonlinear relationship with dv (r = .734, P < .01). With the addition of the maximum impulse to dF, multiple-regression analysis explained 83% of the free-swimming performance. Conclusions: Assessing dF is a promising approach for evaluating a swimmer’s performance. From the experiments, this new parameter showed that swimmers with higher dF also present higher dv, leading to a decrease in performance.

STUDIES OF TROPICAL TUNA SWIMMING PERFORMANCE IN A LARGE WATER TUNNEL - KINEMATICS

1994 ◽  
Vol 192 (1) ◽  
pp. 45-59 ◽  
Author(s):  
H Dewar ◽  
J Graham
Keyword(s):  
Swimming Performance ◽  
Beat Frequency ◽  
Fork Length ◽  
Swimming Velocity ◽  
Water Tunnel ◽  
Pectoral Fins ◽  
Swimming Mode ◽  
Anatomical Adaptations ◽  
Large Water ◽  
Tropical Tuna

Yellowfin tuna (Thunnus albacares) swimming kinematics was studied in a large water tunnel at controlled swimming velocities (U). Quantified kinematic variables included the tail-beat frequency, stride length (l), caudal amplitude, yaw, the propulsive wavelength, the speed of the propulsive wave (C) and the sweepback angle of the pectoral fins. In general, all variables, except the propulsive wavelength and consequently C, are comparable to values determined for other teleosts. The propulsive wavelength for the tunas (1.23&shy;1.29 L, where L is fork length) is 30&shy;60 % longer than in other cruise-adapted teleosts such as salmonids. The resulting thunniform swimming mode and the morphological and anatomical adaptations associated with the long propulsive wavelength (e.g. fusiform body shape, rigid vertebral column) act to minimize anterior resistance and maximize caudal thrust. The long propulsive wavelength also increases the maximum l which, in concert with the elevated muscle temperatures of tunas, increases their maximum swimming velocity.

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