Simplified Triped Robot for Analysis of Three-Dimensional Gait Generation

2017 ◽  
Vol 29 (3) ◽  
pp. 528-535
Author(s):  
Yoichi Masuda ◽  
◽  
Masato Ishikawa
Keyword(s):  
High Speed ◽  
Force Feedback ◽  
Three Dimensional ◽  
Radial Symmetry ◽  
The Body ◽  
Walking Robots ◽  
Body Structure ◽  
Gait Patterns ◽  
Gait Generation ◽  
Proposed Model

[abstFig src='/00290003/08.jpg' width='230' text='The tripedal robot “Martian petit”' ] Significant efforts to simplify the body structure of multi-legged walking robots have been made over the years. Of these, the Spring-Loaded-Inverted-Pendulum (SLIP) model has been very popular, therefore widely employed in the design of walking robots. In this paper, we develop a SLIP-based tripedal walking robot with a focus on the geometric symmetry of the body structure. The proposed robot possesses a compact, light-weight, and compliant leg modules. These modules are controlled by a distributed control law that consists of decoupled oscillators with only local force feedback. As demonstrated through experiments, the simplified design of the robot makes possible the generation of high-speed dynamic locomotion. Despite the structural simplicity of the proposed model, the generation of several gait-patterns is demonstrated. The proposed minimalistic design approach with radial symmetry simplifies the function of each limb in the three-dimensional gait generation of the robot.

scholarly journals A faster escape does not enhance survival in zebrafish larvae

2017 ◽  
Vol 284 (1852) ◽  
pp. 20170359 ◽  
Author(s):  
Arjun Nair ◽  
Christy Nguyen ◽  
Matthew J. McHenry
Keyword(s):  
High Speed ◽  
Larval Fish ◽  
Body Position ◽  
Three Dimensional ◽  
Limited Range ◽  
The Body ◽  
Model Parameters ◽  
Fish Prey ◽  
Zebrafish Larvae ◽  
Fish Predators

An escape response is a rapid manoeuvre used by prey to evade predators. Performing this manoeuvre at greater speed, in a favourable direction, or from a longer distance have been hypothesized to enhance the survival of prey, but these ideas are difficult to test experimentally. We examined how prey survival depends on escape kinematics through a novel combination of experimentation and mathematical modelling. This approach focused on zebrafish ( Danio rerio ) larvae under predation by adults and juveniles of the same species. High-speed three-dimensional kinematics were used to track the body position of prey and predator and to determine the probability of behavioural actions by both fish. These measurements provided the basis for an agent-based probabilistic model that simulated the trajectories of the animals. Predictions of survivorship by this model were found by Monte Carlo simulations to agree with our observations and we examined how these predictions varied by changing individual model parameters. Contrary to expectation, we found that survival may not be improved by increasing the speed or altering the direction of the escape. Rather, zebrafish larvae operate with sufficiently high locomotor performance due to the relatively slow approach and limited range of suction feeding by fish predators. We did find that survival was enhanced when prey responded from a greater distance. This is an ability that depends on the capacity of the visual and lateral line systems to detect a looming threat. Therefore, performance in sensing, and not locomotion, is decisive for improving the survival of larval fish prey. These results offer a framework for understanding the evolution of predator–prey strategy that may inform prey survival in a broad diversity of animals.

Dynamically and Biologically Inspired Legged Locomotion: A Review

2017 ◽  
Vol 29 (3) ◽  
pp. 456-470 ◽  
Author(s):  
Tetsuya Kinugasa ◽  
◽  
Yasuhiro Sugimoto ◽  
Keyword(s):  
Joint Stiffness ◽  
Legged Locomotion ◽  
Travel Speed ◽  
The Body ◽  
Biological Characteristics ◽  
Body Structure ◽  
Special Issue ◽  
Biologically Inspired ◽  
Contact Conditions ◽  
Gait Patterns

[abstFig src='/00290003/01.jpg' width='300' text='Passive dynamic walking: RW03 and Jenkka III' ] Legged locomotion, such as walking, running, turning, and jumping depends strongly on the dynamics and the biological characteristics of the body involved. Gait patterns and energy efficiency, for instance, are known to be greatly affected, not only by travel speed and ground contact conditions but also by body structure such as joint stiffness and coordination, and foot sole shape. To understand legged locomotion principles, we must elucidate how the body’s dynamic and biological characteristics affect locomotion. Efforts should also be made to incorporate these characteristics inventively in order to improve locomotion performance with regard to robustness, adaptability, and efficiency, which realize more refined legged locomotion. For this special issue, we invited our readers to submit papers with approaches to achieving legged locomotion based on dynamic and biological characteristics and studies investigating the effects of these characteristics. In this paper, we review studies on dynamically and biologically inspired legged locomotion.

Simple mechanisms organise orientation of escape swimming in embryos and hatchling tadpoles of Xenopus laevis

2000 ◽  
Vol 203 (12) ◽  
pp. 1869-1885 ◽  
Author(s):  
A. Roberts ◽  
N.A. Hill ◽  
R. Hicks
Keyword(s):  
Mathematical Model ◽  
Xenopus Laevis ◽  
High Speed ◽  
Three Dimensional ◽  
Longitudinal Axis ◽  
The Body ◽  
Video Recordings ◽  
Stage Of Development ◽  
Physical Features ◽  
Neutrally Buoyant

Many amphibian tadpoles hatch and swim before their inner ears and sense of spatial orientation differentiate. We describe upward and downward swimming responses in hatchling Xenopus laevis tadpoles from stages 32 to 37/38 in which the body rotates about its longitudinal axis. Tadpoles are heavier than water and, if touched while lying on the substratum, they reliably swim upwards, often in a tight spiral. This response has been observed using stroboscopic photography and high-speed video recordings. The sense of the spiral is not fixed for individual tadpoles. In ‘more horizontal swimming’ (i.e. in directions within +/−30 degrees of the horizontal), the tadpoles usually swim belly-down, but this position is not a prerequisite for subsequent upward spiral swimming. Newly hatched tadpoles spend 99 % of their time hanging tail-down from mucus secreted by a cement gland on the head. When suspended in mid-water by a mucus strand, tadpoles from stage 31 to 37/38 tend to swim spirally down when touched on the head and up when touched on the tail. The three-dimensional swimming paths of stage 33/34 tadpoles were plotted using simultaneous video images recorded from the side and from above. Tadpoles spiralled for 70 % of the swimming time, and the probability of spiralling increased to 1 as swim path angles became more vertical. Tadpoles were neutrally buoyant in Percoll/water mixtures at 1.05 g cm(−)(3), in which anaesthetised tadpoles floated belly-down and head-up at 30 degrees. In water, their centre of mass was ventral to the muscles in the yolk mass. A simple mathematical model suggests that the orientation of tadpoles during swimming is governed by the action of two torques, one of which raises the head (i.e. increases the pitch) and the other rotates (rolls) the body. Consequently, tadpoles (i) swim belly-down when the body is approximately horizontal because the body is ballasted by dense yolk, and (ii) swim spirally at more vertical orientations when the ballasting no longer stabilises orientation. Measurements in tethered tadpoles show that dorsal body flexion, which could produce a dorsal pitch torque, is present during swimming and increases with tailbeat frequency. We discuss how much of the tadpole's behaviour can be explained by our mathematical model and suggest that, at this stage of development, oriented swimming responses may depend on simple touch reflexes, the organisation of the muscles and physical features of the body, rather than on vestibular reflexes.

Analysis of a Low Effort Rectilinear Gait for a Snake-Inspired Robot

2013 ◽  
Author(s):  
James K. Hopkins ◽  
Satyandra K. Gupta
Keyword(s):  
High Speed ◽  
Linear Displacement ◽  
The Body ◽  
Positive Trend ◽  
Rectilinear Motion ◽  
Body Structure ◽  
Joint Effort ◽  
Cyclic Displacement ◽  
Robot Platform

In recent years, snake-inspired locomotion has garnered increasing interest in the bio-inspired robotics community. This positive trend is largely due to the unique and highly effective gaits utilized by snakes to traverse various terrains and obstacles. These gaits make use of a snake’s hyper-redundant body structure to adapt to the terrain and maneuver through tight spaces. Snake-inspired robots utilizing rectilinear motion, one of the primary gaits observed in natural snakes, have demonstrated favorable results on various terrains. However, previous variations of the rectilinear gait were inefficient in cyclic displacement. These gaits generated vertical waves traveling along the length of the robot. Generating these waves required significant joint energy for relatively small horizontal displacements. This paper presents analytical and experimental results for a rectilinear gait, which demonstrates significant linear displacement for relatively low joint effort. The low effort gait functions by propagating a wave through the length of the robot via expansions and contractions of the body segments, propelling the robot platform forward. The low effort rectilinear gait is demonstrated on a robot platform that incorporates high speed linear motion and variable traction through friction. We also report the results of a case study showcasing the practical benefits of the low effort gait.

scholarly journals The impact of pelvic lateral rotation on hindlimb kinematics and stride length in the red-legged running frog, Kassina maculata

2019 ◽  
Vol 6 (5) ◽  
pp. 190060 ◽  
Author(s):  
Amber J. Collings ◽  
Laura B. Porro ◽  
Cameron Hill ◽  
Christopher T. Richards
Keyword(s):  
High Speed ◽  
Stride Length ◽  
Reference Frames ◽  
Comparative Anatomy ◽  
Three Dimensional ◽  
Video Data ◽  
The Body ◽  
Kinematic Models ◽  
Lateral Rotation ◽  
The Impact

Some frog species, such as Kassina maculata (red-legged running frog), use an asynchronous walking/running gait as their primary locomotor mode. Prior comparative anatomy work has suggested that lateral rotation of the pelvis improves walking performance by increasing hindlimb stride length; however, this hypothesis has never been tested. Using non-invasive methods, experimental high-speed video data collected from eight animals were used to create two three-dimensional kinematic models. These models, each fixed to alternative local anatomical reference frames, were used to investigate the hypothesis that lateral rotation of the mobile ilio-sacral joint in the anuran pelvis plays a propulsive role in walking locomotion by increasing hindlimb stride length. All frogs used a walking gait (duty factor greater than 0.5) despite travelling over a range of speeds (0.04–0.23 m s −1 ). The hindlimb joint motions throughout a single stride were temporally synchronized with lateral rotation of the pelvis. The pelvis itself, on average, underwent an angular excursion of 12.71° (±4.39°) with respect to the body midline during lateral rotation. However, comparison between our two kinematic models demonstrated that lateral rotation of the pelvis only increases the cranio-caudal excursion of the hindlimb modestly. Thus, we propose that pelvic lateral rotation is not a stride length augmenting mechanism in K. maculata .

scholarly journals Three-dimensional simulation for fast forward flight of a calliope hummingbird

2016 ◽  
Vol 3 (6) ◽  
pp. 160230 ◽  
Author(s):  
Jialei Song ◽  
Bret W. Tobalske ◽  
Donald R. Powers ◽  
Tyson L. Hedrick ◽  
Haoxiang Luo
Keyword(s):  
Immersed Boundary Method ◽  
High Speed ◽  
Computational Study ◽  
Three Dimensional ◽  
The Body ◽  
Immersed Boundary ◽  
Forward Flight ◽  
Advance Ratio ◽  
Dimensional Simulation ◽  
Thrust Production

We present a computational study of flapping-wing aerodynamics of a calliope hummingbird ( Selasphorus calliope ) during fast forward flight. Three-dimensional wing kinematics were incorporated into the model by extracting time-dependent wing position from high-speed videos of the bird flying in a wind tunnel at 8.3 m s −1 . The advance ratio, i.e. the ratio between flight speed and average wingtip speed, is around one. An immersed-boundary method was used to simulate flow around the wings and bird body. The result shows that both downstroke and upstroke in a wingbeat cycle produce significant thrust for the bird to overcome drag on the body, and such thrust production comes at price of negative lift induced during upstroke. This feature might be shared with bats, while being distinct from insects and other birds, including closely related swifts.

scholarly journals Biomechanical factor affecting Baseball Pitching Velocity

2019 ◽  
Author(s):  
Yasushi Ota ◽  
Ryoga Kuriyama
Keyword(s):  
High Speed ◽  
Time Series Data ◽  
Three Dimensional ◽  
The Body ◽  
Lower Limbs ◽  
Whole Body ◽  
Series Data ◽  
Physical Factors ◽  
Body Parts ◽  
Joint Force

In baseball, pitchers have a central role and high-speed pitching is desirable. So far, several studies of the physical factors related to pitching form with the aim of improving the speed of pitched balls have been conducted. In this study, we used a motion capture to acquire three-dimensional (3D) time series data related to the speed of pitched balls and performed a kinetics analysis by using these acquired data. The acquired data were divided into five pitching phases: wind up, early cocking, late cocking, acceleration, and follow through. Our analysis identified the body parts that contribute to increasing the speed of pitched balls, i.e., the speed of rotation of individual joints and the timing/phase when power can be applied. Especially, by examining joint angular velocity and joint force, we showed that the speed of pitched balls is determined by the action of the upper limbs as well as the coordinated action of the whole body, particularly the lower limbs and the trunk.

scholarly journals Simple decentralized control mechanism that enables limb adjustment for adaptive quadruped running

2021 ◽  
Vol 288 (1962) ◽  
Author(s):  
Akira Fukuhara ◽  
Yukihiro Koizumi ◽  
Tomoyuki Baba ◽  
Shura Suzuki ◽  
Takeshi Kano ◽  
...  
Keyword(s):  
Stance Phase ◽  
Control Mechanism ◽  
Interlimb Coordination ◽  
The Body ◽  
Coordination Mechanism ◽  
Body Parts ◽  
Gait Patterns ◽  
Mechanical Loads ◽  
Proposed Model ◽  
Simulation Results

Quadrupeds exhibit versatile and adaptive running by exploiting the flying phase during the stride cycle. Various interlimb coordination mechanisms focusing on mechanical loads during the stance phase have been proposed to understand the underlying control mechanism, and various gait patterns have been reproduced. However, the essential control mechanism required to achieve both steady running patterns and non-steady behaviours, such as jumping and landing, remains unclear. Therefore, we focus on the vertical motions of the body parts and propose a new decentralized interlimb coordination mechanism. The simulation results demonstrate that the robot can generate efficient and various running patterns in response to the morphology of the body. Furthermore, the proposed model allows the robot to smoothly change its behaviour between steady running and non-steady landing depending on the situation. These results suggest that the steady and non-steady behaviours in quadruped adaptive running may share a common simple control mechanism based on the mechanical loads and vertical velocities of the body parts.

Three-dimensional kinematics and limb kinetic energy of running cockroaches.

1997 ◽  
Vol 200 (13) ◽  
pp. 1919-1929 ◽  
Author(s):  
R Kram ◽  
B Wong ◽  
R J Full
Keyword(s):  
Kinetic Energy ◽  
High Speed ◽  
Mechanical Energy ◽  
Center Of Mass ◽  
Three Dimensional ◽  
The Body ◽  
Morphological Data ◽  
Fast Running ◽  
Total Mechanical Energy ◽  
Reaction Forces

We tested the hypothesis that fast-running hexapeds must generate high levels of kinetic energy to cycle their limbs rapidly compared with bipeds and quadrupeds. We used high-speed video analysis to determine the three-dimensional movements of the limbs and bodies of cockroaches (Blaberus discoidalis) running on a motorized treadmill at 21 cm s-1 using an alternating tripod gait. We combined these kinematic data with morphological data to calculate the mechanical energy produced to move the limbs relative to the overall center of mass and the mechanical energy generated to rotate the body (head + thorax + abdomen) about the overall center of mass. The kinetic energy involved in moving the limbs was 8 microJ stride-1 (a power output of 21 mW kg-1, which was only approximately 13% of the external mechanical energy generated to lift and accelerate the overall center of mass at this speed. Pitch, yaw and roll rotational movements of the body were modest (less than +/- 7 degrees), and the mechanical energy required for these rotations was surprisingly small (1.7 microJ stride-1 for pitch, 0.5 microJ stride-1 for yaw and 0.4 microJ stride-1 for roll) as was the power (4.2, 1.2 and 1.1 mW kg-1, respectively). Compared at the same absolute forward speed, the mass-specific kinetic energy generated by the trotting hexaped to swing its limbs was approximately half of that predicted from data on much larger two- and four-legged animals. Compared at an equivalent speed (mid-trotting speed), limb kinetic energy was a smaller fraction of total mechanical energy for cockroaches than for large bipedal runners and hoppers and for quadrupedal trotters. Cockroaches operate at relatively high stride frequencies, but distribute ground reaction forces over a greater number of relatively small legs. The relatively small leg mass and inertia of hexapeds may allow relatively high leg cycling frequencies without exceptionally high internal mechanical energy generation.

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