Topic
Body roll
About: Body roll is a research topic. Over the lifetime, 222 publications have been published within this topic receiving 2706 citations.
Papers published on a yearly basis
Papers
TL;DR: Video records were made of the blowfly Calliphora erythrocephala L. mainly during tethered flight in a wind-tunnel, to study its movements about the longitudinal body axis (roll), and the limits of fly vision and the advantages of compensatory head movements for different visually guided behaviour are discussed.
Abstract: Video records were made of the blowfly Calliphora erythrocephala L. mainly during tethered flight in a wind-tunnel, to study its movements about the longitudinal body axis (roll). During undisturbed flight, flies hold their head on average aligned with the body but may turn it about all three body axes. Pitch and yaw turns of the head are comparatively small (20 degrees), whereas roll turns can be large (90 degrees), and fast (1200 degrees s$^{-1}$). When passively rolled, flies produce compensatory head movements during walking or flight; at rest this reflex is turned off. Flies perceive a static misalignment relative to the vertical, as well as roll motion up to 10 000 degrees s$^{-1}$. Within this range flies counteract an imposed roll with maximal gain at about 1000 degrees s$^{-1}$. Compensatory head movements are made with very low latency (down to $\Delta $t $\approx $ 5 ms), and with considerable speed (up to $\omega $ = 1000 degrees s$^{-1}$). Flies may `disregard an apparent deviation from their correct orientation, and may superimpose spontaneous head movements on those elicited by a stimulus. Compensatory head movements generally undercompensate the imposed misalignment. Simultaneously, however, flies modify their wing pitch and wingbeat amplitude to produce a compensatory roll torque. Since head and body roll act simultaneously and in the same direction, the overall speed and degree of head realignment, relative to external coordinates, increase considerably. This is certainly an advantage for flight in turbulent air. In still air, without need to correct an imposed misalignment, flies nevertheless produce spontaneous fluctuations of their flight torque, and head roll movements in the opposite direction. This is to be expected if flies intend to keep their eyes aligned with the coordinates of the environment while spontaneously performing banked turns. The limits of fly vision and the advantages of compensatory head movements for different visually guided behaviour are discussed. Compensatory head roll movements give flies greater manoeuvrability when cruising than the visual system would allow, without such a stabilizing reflex.
234 citations
TL;DR: A new three-dimensional analytical model was developed that predicted an increase in body roll and turning as tails increase in length relative to the body and reinforced how effective attitude control can be attained with simple movements of an inertial appendage.
Abstract: Unlike the falling cat, lizards can right themselves in mid-air by a swing of their large tails in one direction causing the body to rotate in the other. Here, we developed a new three-dimensional analytical model to investigate the effectiveness of tails as inertial appendages that change body orientation. We anchored our model using the morphological parameters of the flat-tailed house gecko Hemidactylus platyurus. The degree of roll in air righting and the amount of yaw in mid-air turning directly measured in house geckos matched the model’s results. Our model predicted an increase in body roll and turning as tails increase in length relative to the body. Tails that swung from a near orthogonal plane relative to the body (i.e. 0‐30 ◦ from vertical) were the most effective at generating body roll, whereas tails operating at steeper angles (i.e. 45‐60 ◦ ) produced only half the rotation. To further test our analytical model’s predictions, we built a bio-inspired robot prototype. The robot reinforced how effective attitude control can be attained with simple movements of an inertial appendage.
140 citations
TL;DR: For example, in a study of 12 male 100m freestyle swimmers during the 1992 Olympic Games, Schleihauf et al. as discussed by the authors found that elite swimmers were different from subelites in that their pulling patterns were more efficient and their body position was more streamlined.
Abstract: Twelve male 100-m freestyle swimmers were videotaped during the 1992 Olympic Games. Four cameras, two above water and two below, recorded the same stroke cycle of the swimmer at approximately the 40- to 45-m mark. The whole body and the recovering arms were digitized from the videotapes to recreate a complete stroke cycle. Body position variables and hand reaction forces (Schleihauf, 1979) were calculated. Swimmers were divided into elite and subelite groups based on their swimming velocity and were compared for differences in biomechanical variables. Elites used slightly lower hand forces while maintaining a higher propelling efficiency. Subelites had opposite rotations about the longitudinal axis of the body rather than symmetrical body roll. The elite swimmers were different from subelites in that their pulling patterns were more efficient and their body position was more streamlined. These variables assisted them in achieving faster swimming velocities without requiring higher propulsive forces.
94 citations
Journal Article•
TL;DR: Combat sports do not appear to have higher injury rates compared to non-combat sports and injury prevention efforts should consider the distribution of injuries and concentrate on preventing strains/sprains in wrestling, concussions in boxing and wrestling, and fractures for all three activities.
Abstract: The aim of the present study was to determine the effects of breathing on the three - dimensional underwater stroke kinematics of front crawl swimming. Ten female competitive freestyle swimmers participated in the study. Each subject swam a number of front crawl trials of 25 m at a constant speed under breathing and breath-holding conditions. The underwater motion of each subject's right arm was filmed using two S-VHS cameras, operating at 60 Hz, which were positioned behind two underwater viewing windows. The spatial coordinates of selected points were calculated using the DLT procedure with 30 control points and after the digital filtering of the raw data with a cut-off frequency of 6 Hz, the hand's linear displacements and velocities were calculated. The results revealed that breathing caused significantly increases in the stroke duration (t9 = 2.764; p < 0.05), the backward hand displacement relative to the water (t9 = 2.471; p<0.05) and the lateral displacement of the hand in the X - axis during the downsweep (t9 = 2.638; p < 0.05). On the contrary, the peak backward hand velocity during the insweep (t9 = 2.368; p < 0.05) and the displacement of the hand during the push phase (t9 = -2.297; p < 0.05) were greatly reduced when breathing was involved. From the above, it was concluded that breathing action in front crawl swimming caused significant modifications in both the basic stroke parameters and the overall motor pattern were, possibly due to body roll during breathing. Key pointsThe breathing action increases the duration of the total underwater pull.The breathing action increases the absolute backward displacement of the hand.The breathing action caused significant modifications in the overall motor pattern, possibly due to body roll during breathing.
93 citations
Patent•
10 Mar 1987
TL;DR: In this article, a system for vehicle roll control, a suspension device or an actuator is provided corresponding to each wheel of a vehicle, and resiliently suspends it from the vehicle body.
Abstract: In this system for vehicle roll control, a suspension device or an actuator is provided corresponding to each wheel of a vehicle, and resiliently suspends it from the vehicle body. Each such suspension device can alter its hardness or softness characteristics according to a control signal, while similarly the actuators are adapted to alter the suspended height of their wheels. A vehicle speed detecting device senses road speed, a steering angle detecting device senses steering angle, and a device detects the total vehicle body weight. A computing control device computes a predictive roll angle of the vehicle body from road speed and steering angle, and: if suspension devices are provided, controls them to be relatively hard when the absolute value of the predictive roll angle is larger than a threshold value, while controlling them to be relatively soft when the absolute value of the predictive roll angle is less than this threshold value; while, if actuators are provided, when the absolute value of the predictive roll angle is larger than a threshold value, it controls them in accordance with this predictive roll angle. Particularly, this computing device varies the threshold roll angle value according to the total vehicle body weight as detected by the weight detector, so as to decrease the threshold roll angle value along with increase of the total vehicle body weight.
76 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 7 |
| 2020 | 5 |
| 2019 | 17 |
| 2018 | 9 |
| 2017 | 8 |
| 2016 | 13 |