Engineering observation of lateral undulation in colubrid snakes for wheel-less locomotion

Robotica ◽  
2011 ◽  
Vol 30 (7) ◽  
pp. 1079-1093 ◽  
Author(s):  
Farshad Barazandeh ◽  
Hossein Rahnamafard ◽  
Mehdi Rajabizadeh ◽  
Hossein Faraji
Keyword(s):  
Point Of View ◽  
The Body ◽  
Smooth Surfaces ◽  
Field Observations ◽  
Snake Robot ◽  
Muscular Structure ◽  
Lateral Undulation ◽  
Snake Robots

SUMMARYNature has always inspired engineers. This research tries to understand the contribution of snake anatomy in its locomotion from engineering point of view to be adopted in the design of snake robots. Rib design and muscular structure of snake robots will have a great impact on snake robot flexibility, weight, and actuators' torque. It will help to eliminate wheels in snake robots during serpentine locomotion. The result of this research shows that snakes can establish the required peg points on smooth surfaces by deflecting the body and ribs. The results are verified by both field observations and simulation.

Modeling and Mechanical Analysis of Snake Robots on Cylinders

2019 ◽  
Vol 11 (4) ◽  
Author(s):  
Chaoquan Tang ◽  
Peng Li ◽  
Gongbo Zhou ◽  
Deyuan Meng ◽  
Xin Shu ◽  
...  
Keyword(s):  
Mechanical Analysis ◽  
Point Of View ◽  
The Body ◽  
Optimal Method ◽  
Tree Structures ◽  
Snake Robot ◽  
Mechanical Models ◽  
And Performance ◽  
The Relationship ◽  
Snake Robots

The narrow and redundant body of the snake robot makes it suitable for the inspection of complex bar structures, such as truss or tree structures. One of the key issues affecting the efficient motion of snake robots in complex bar structures is the development of mechanical models of snake robots on cylinders. In other words, the relationship between the payload and structural and performance parameters of the snake robot is still difficult to clarify. In this paper, the problem is approached with the Newton–Euler equations and the convex optimal method. Firstly, from the kinematic point of view, the optimal attitude of the snake robot wrapped around the cylinder is found. Next, the snake robot is modeled on the cylinder and transformed into a convex optimization problem. Then, the relationship between the payload of the snake robot on the cylinder and the geometric and attitude parameters of the body of snake robots is analyzed. Finally, the discussion for the optimal winding attitude and some advices for the design of the snake robot are proposed. This study is helpful toward the optimal design of snake robots, including geometry parameters and motor determination.

scholarly journals A Head Control Strategy of the Snake Robot Based on Segmented Kinematics

2019 ◽  
Vol 9 (23) ◽  
pp. 5104
Author(s):  
Yunhu Zhou ◽  
Yuanfei Zhang ◽  
Fenglei Ni ◽  
Hong Liu
Keyword(s):  
Control Strategy ◽  
Control Strategies ◽  
The Body ◽  
Head Part ◽  
Joint Angles ◽  
Backbone Curve ◽  
Snake Robot ◽  
Head Control ◽  
Neck Part ◽  
Snake Robots

Head control is important for snake robots to work in an unknown environment. However, the existing methods of head control have certain application limitations for snake robots with different configurations. Thus, a strategy for head control based on segmented kinematics is proposed. Compared with the existing head control strategies, our strategy can adapt to different structures of snake robots, whether wheeled or non-wheeled. In addition, our strategy can realize the accurate manipulation of the snake robot head. The robot body is divided into the base part, neck part and head part. First, parameters of backbone curve are optimized for enlarging the area of the support polygon. Then the desired pose for the head link and the dexterous workspace of the head part can in turn derive the desired position and direction of the end frame for the neck part. An optimization algorithm is proposed to help the end frame of the neck part approach a desired one and obtains the joint angles of the neck part. When the actual frames of the neck part are determined, the dexterous workspace of the head part will cover the desired pose of the head link. Then the TRAC-IK inverse kinematics algorithm is adopted to solve the joint angles of the head part. To avoid the collision between the body and the ground, a trajectory planning method of the overall body in Cartesian space is proposed. Finally, simulations validate the effectiveness of the control strategy.

Gait Fitting Algorithms for Snake Robots With Binary Actuators

2012 ◽  
Author(s):  
Yunjie Miao ◽  
Feng Gao ◽  
Yong Zhang
Keyword(s):  
Snake Robot ◽  
Fitting Algorithm ◽  
Lateral Undulation ◽  
Best Fitting ◽  
Different Dimensions ◽  
Binary Actuators ◽  
Snake Robots

This paper introduces a new snake robot with binary actuators and mainly focuses on the simulations of various snake gaits. Three categories of fitting algorithms are proposed. They are 1) Fitting Algorithm of One Module; 2) Position-Fitting Algorithm of Multiple Modules; 3) Configuration-Fitting Algorithm of Multiple Modules. All the fitting algorithms and their fitting results are elaborated in simulations of lateral undulation, one of the most widely used snake gaits. As the best fitting algorithm for lateral undulation, Configuration-Fitting Algorithm of Four Modules is also applied to a snake robot of different dimensions to demonstrate that it is a universal gait fitting algorithm for all kinds of snake robots with binary actuators.

scholarly journals Robotic modelling of snake traversing large, smooth obstacles reveals stability benefits of body compliance

2020 ◽  
Vol 7 (2) ◽  
pp. 191192 ◽  
Author(s):  
Qiyuan Fu ◽  
Chen Li
Keyword(s):  
Complex Terrain ◽  
Search And Rescue ◽  
Anisotropic Friction ◽  
Snake Robot ◽  
Flat Surfaces ◽  
Out Of Plane ◽  
Lateral Undulation ◽  
Anchor Points ◽  
Desert Dunes ◽  
Snake Robots

Snakes can move through almost any terrain. Although their locomotion on flat surfaces using planar gaits is inherently stable, when snakes deform their body out of plane to traverse complex terrain, maintaining stability becomes a challenge. On trees and desert dunes, snakes grip branches or brace against depressed sand for stability. However, how they stably surmount obstacles like boulders too large and smooth to gain such ‘anchor points’ is less understood. Similarly, snake robots are challenged to stably traverse large, smooth obstacles for search and rescue and building inspection. Our recent study discovered that snakes combine body lateral undulation and cantilevering to stably traverse large steps. Here, we developed a snake robot with this gait and snake-like anisotropic friction and used it as a physical model to understand stability principles. The robot traversed steps as high as a third of its body length rapidly and stably. However, on higher steps, it was more likely to fail due to more frequent rolling and flipping over, which was absent in the snake with a compliant body. Adding body compliance reduced the robot's roll instability by statistically improving surface contact, without reducing speed. Besides advancing understanding of snake locomotion, our robot achieved high traversal speed surpassing most previous snake robots and approaching snakes, while maintaining high traversal probability.

scholarly journals Lateral undulation of snake robots: a simplified model and fundamental properties

Robotica ◽  
2013 ◽  
Vol 31 (7) ◽  
pp. 1005-1036 ◽  
Author(s):  
Pål Liljebäck ◽  
Kristin Y. Pettersen ◽  
Øyvind Stavdahl ◽  
Jan Tommy Gravdahl
Keyword(s):  
Equilibrium Point ◽  
Sufficient Conditions ◽  
Gait Pattern ◽  
Small Time ◽  
Local Controllability ◽  
Simplified Model ◽  
Snake Robot ◽  
Gait Parameters ◽  
Lateral Undulation ◽  
Snake Robots

SUMMARYThis paper considers the lateral undulation motion of snake robots. The first contribution of the paper is a model of lateral undulation dynamics developed for control design and stability analysis purposes. The second contribution is an analysis of the simplified model that shows that any asymptotically stabilizing control law for the snake robot to an equilibrium point must be time varying. Furthermore, the analysis shows that a snake robot (with four links) is strongly accessible from almost any equilibrium point, except for certain singular configurations, and that the robot does not satisfy sufficient conditions for small-time local controllability. The third contribution is based on using averaging theory to prove that the average velocity of the robot during lateral undulation will converge exponentially fast to a steady-state velocity which is given analytically as a function of the gait pattern parameters. From the averaging analysis, we also derive a set of fundamental relationships between the gait parameters of lateral undulation and the resulting forward velocity of the snake robot. The paper presents simulation results and results from experiments with a physical snake robot that support the theoretical findings.

Integrating Focusing and Differentiation: A Therapeutic Path for Couples in Intimate Relationships

2018 ◽  
Vol 3 ◽  
Author(s):  
Evi Zohar
Keyword(s):  
Couples Therapy ◽  
Therapeutic Potential ◽  
Well Being ◽  
Point Of View ◽  
The Body ◽  
Self Awareness ◽  
Emotional Healing ◽  
Felt Sense ◽  
Inner World

Continuing the workshop I've given in the WPC Paris (2017), this article elaborates my discussion of the way I interlace Focusing with Differentiation Based Couples Therapy (Megged, 2017) under the systemic view, in order to facilitate processes of change and healing in working with intimate couples. This article presents the theory and rationale of integrating Differentiation (Bowen, 1978; Schnarch, 2009; Megged, 2017) and Focusing (Gendlin, 1981) approaches, and its therapeutic potential in couple's therapy. It is written from the point of view of a practicing professional in order to illustrate the experiential nature and dynamics of the suggested therapeutic path. Differentiation is a key to mutuality. It offers a solution to the central struggle of any long term intimate relationship: balancing two basic life forces - the drive for individuality and the drive for togetherness (Schnarch, 2009). Focusing is a body-oriented process of self-awareness and emotional healing, in which one learns to pay attention to the body and the ‘Felt Sense’, in order to unfold the implicit, keep it in motion at the precise pace it needs for carrying the next step forward (Gendlin, 1996). Combining Focusing and Differentiation perspectives can cultivate the kind of relationship where a conflict can be constructively and successfully held in the inner world of each partner, while taking into consideration the others' well-being. This creates the possibility for two people to build a mutual emotional field, open to changes, permeable and resilient.

Presentation

2014 ◽  
Vol 2 (3) ◽  
Author(s):  
Redacción CEIICH
Keyword(s):  
Cultural History ◽  
Social Reality ◽  
Point Of View ◽  
The Body ◽  
Literary Studies ◽  
The Third ◽  
The Social ◽  
Feminist Theories ◽  
History Of

<p class="p1">The third number of <span class="s1"><strong>INTER</strong></span><span class="s2"><strong>disciplina </strong></span>underscores this generic reference of <em>Bodies </em>as an approach to a key issue in the understanding of social reality from a humanistic perspective, and to understand, from the social point of view, the contributions of the research in philosophy of the body, cultural history of the anatomy, as well as the approximations queer, feminist theories and the psychoanalytical, and literary studies.</p>

scholarly journals Transition from Emotional to Rational Advertising for Food Products on the Romanian Market

2017 ◽  
Vol 50 (1) ◽  
pp. 101-108
Author(s):  
A.F. Jităreanu ◽  
Elena Leonte ◽  
A. Chiran ◽  
Benedicta Drobotă
Keyword(s):  
Urban Areas ◽  
Eating Habits ◽  
Well Being ◽  
Point Of View ◽  
The Body ◽  
Positive Effects ◽  
New Methods ◽  
Brand Advertising ◽  
Tangible Evidence ◽  
Health And Well Being

Abstract Advertising helps to establish a set of assumptions that the consumer will bring to all other aspects of their engagement with a given brand. Advertising provides tangible evidence of the financial credibility and competitive presence of an organization. Persuasion is becoming more important in advertising. In marketing, persuasive advertising acts to establish wants/motivations and beliefs/attitudes by helping to formulate a conception of the brand as being one which people like those in the target audience would or should prefer. Considering the changes in lifestyle and eating habits of a significant part of the population in urban areas in Romania, the paper aims to analyse how brands manage to differentiate themselves from competitors, to reposition themselves on the market and influence consumers, meeting their increasingly varied needs. Food brands on the Romanian market are trying, lately, to identify new methods of differentiation and new benefits for their buyers. Given that more and more consumers are becoming increasingly concerned about what they eat and the products’ health effects, brands struggle to highlight the fact that their products offer real benefits for the body. The advertisements have become more diversified and underline the positive effects, from the health and well - being point of view, that those foods offer (no additives and preservatives, use of natural ingredients, various vitamins and minerals or the fact that they are dietary). Advertising messages’ diversification is obvious on the Romanian market, in the context of an increasing concern of the population for the growing level of information of some major consumer segments.

scholarly journals Slithering CSF: Cerebrospinal Fluid Dynamics in the Stationary and Moving Viper Boa, Candoia aspera

Biology ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 672
Author(s):  
Bruce A. Young ◽  
Skye Greer ◽  
Michael Cramberg
Keyword(s):  
Cerebrospinal Fluid ◽  
Cardiac Cycle ◽  
Low Frequency ◽  
Mean Amplitude ◽  
The Body ◽  
Body Waves ◽  
Lower Amplitude ◽  
Lateral Undulation ◽  
Recovery From Anesthesia ◽  
The Relationship

In the viper boa (Candoia aspera), the cerebrospinal fluid (CSF) shows two stable overlapping patterns of pulsations: low-frequency (0.08 Hz) pulses with a mean amplitude of 4.1 mmHg that correspond to the ventilatory cycle, and higher-frequency (0.66 Hz) pulses with a mean amplitude of 1.2 mmHg that correspond to the cardiac cycle. Manual oscillations of anesthetized C. aspera induced propagating sinusoidal body waves. These waves resulted in a different pattern of CSF pulsations with frequencies corresponding to the displacement frequency of the body and with amplitudes greater than those of the cardiac or ventilatory cycles. After recovery from anesthesia, the snakes moved independently using lateral undulation and concertina locomotion. The episodes of lateral undulation produced similar influences on the CSF pressure as were observed during the manual oscillations, though the induced CSF pulsations were of lower amplitude during lateral undulation. No impact on the CSF was found while C. aspera was performing concertina locomotion. The relationship between the propagation of the body and the CSF pulsations suggests that the body movements produce an impulse on the spinal CSF.

scholarly journals The wave pattern of a doublet in a stream

1928 ◽  
Vol 121 (788) ◽  
pp. 515-523 ◽  
Keyword(s):  
Surface Effect ◽  
Ideal Point ◽  
Finite Size ◽  
Wave Pattern ◽  
Wave Resistance ◽  
Point Of View ◽  
The Body ◽  
Surface Elevation ◽  
More Care ◽  
Forced Waves

The following paper is a study of the surface waves caused by a doublet in a uniform stream, and in particular the variation in the pattern with the velocity of the stream or the depth of the doublet. In most recent work on this subject attention has been directed more to the wave resistance, which can be evaluated with less difficulty than is involved in a detailed study of the waves; in fact, it would seem that it is not necessary for that purpose to know the surface elevation completely, but only certain significant terms at large distances from the disturbance. Recent experimental work has shown con­siderable agreement between theoretical expressions for wave resistance and results for ship models of simple form, and attempts have been made at a similar comparison for the surface elevation in the neighbourhood of the ship. In the latter respect it may be necessary to examine expressions for the surface elevation with more care, as they are not quite determinate; any suitable free disturbance may be superposed upon the forced waves. For instance, it is well known that in a frictionless liquid a possible solution is one which gives waves in advance as well as in the rear of the ship, and the practical solution is obtained by superposing free waves which annul those in advance, or by some equivalent artifice. This process is simple and definite for an ideal point disturbance, but for a body of finite size or a distributed disturbance the complete surface elevation in the neighbourhood of the body requires more careful specification as regards the local part due to each element. It had been intended to consider some expressions specially from this point of view, but as the matter stands at present it would entail a very great amount of numerical calculation, and the present paper is limited to a much simpler problem although also involving considerable computation. A horizontal doublet of given moment is at a depth f below the surface of a stream of velocity c ; the surface effect may be described as a local disturbance symmetrical fore and aft of the doublet together with waves to the rear. Two points are made in the following work.

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