scholarly journals Hybrid Gait Planning of A Hexapod Robot

2020 ◽  
Vol 4 (2) ◽  
pp. 11
Author(s):  
Ruyi Wang

The adapotation of gaits pattern is a basic and important for the hexapod robot to move stably and efficiently, which depends on the servos of the robot’s legs, and also the body structure of the robot.This paper compares the tripod gait and the crab-inspired gait for a specific hexapod to move forward and move backward; turn left and turn right and integrates the two gaits to apply them under different conditions. The hexapod has three servos on each legs, thus the freedom level of each leg is three-degree. From the comparative experiment, this two gait patterns are suitable for different turning demands.

2020 ◽  
Vol 10 (8) ◽  
pp. 2959
Author(s):  
Yiqun Liu ◽  
Xuanxia Fan ◽  
Liang Ding ◽  
Jianfeng Wang ◽  
Tao Liu ◽  
...  

In some hazardous or inaccessible applications, such as earthquake rescue, as a substitute for mankind, robots are expected to perform missions reliably. Unfortunately, the failure of components is difficult to avoid due to the complexity of robot composition and the interference of the environment. Thus, improving the reliability of robots is a crucial problem. The hexapod robot has redundant degrees of freedom due to its multiple joints, making it possible to tolerate the failure of one leg. In this paper, the Fault-Tolerant Tripod (F-TT) gait dealing with the failure of one leg is researched. The Denavit–Hartenberg (D-H) method is exploited to establish a kinematic model for the hexapod robot, the Jacobian matrix is analyzed, and it is proved that the body can be controlled when three legs are supported. Then, an F-TT gait phase sequence planning method based on a stability margin is established, and a method to improve stability is proposed. The trajectory for the center of gravity (COG) and foot is studied. Finally, a simulation model and prototype robot experiments are developed, and the effectiveness of the proposed method is verified.


2017 ◽  
Vol 29 (3) ◽  
pp. 456-470 ◽  
Author(s):  
Tetsuya Kinugasa ◽  
◽  
Yasuhiro Sugimoto ◽  

[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.


2017 ◽  
Vol 29 (3) ◽  
pp. 528-535
Author(s):  
Yoichi Masuda ◽  
◽  
Masato Ishikawa

[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.


2017 ◽  
Vol 1 (1) ◽  
pp. 115
Author(s):  
Sudar Kajin

Growth and development of the child have the nature of a thorough and intertwined relationships between components (health, nutrition, and environment). In general, child development can be grouped into three areas, namely cognitive, affective, and psychomotor, whereas biological growth which includes a change in the body structure. Body structure regarding the changes in bone structure, especially the long bones that have an impact on changes in body size, whereas changes in bodily functions is a result of hormonal changes that affect the physiological function .. The purpose of this development are: 1) Describe the product feasibility study التربية الجسمية for grade XI IPA at MAN I Mojokerto 2) Describe the development of learning tools using process skills can improve learning outcomes subjects التربية الجسمية class XI IPA at MAN I Mojokerto From the results of this development can be concluded: 1) results of expert validation and testing, the model approach process skills is fit for use for subjects of Physical Education, Sport and Health, because the products developed are not revised by experts but from the results of questionnaire of students stated that require revision are: (a) Improve the look model or change the learning strategy, and (b) improve the use of resources in implementing the model. 2) Product development learning tools using process skills can improve learning outcomes subjects التربية الجسمية class XI IPA at MAN I Mojokerto. From the class of the test increased learning completeness of Pre and Post Tests Tests are respectively 77.78% increase to 91.67%.


2017 ◽  
Vol 54 ◽  
pp. 112-119
Author(s):  
L. M. Khmelnychy

The estimation of the first-born cows of Ukrainian Black-and-White dairy breed by the exterior type in the leading breeding herds of Cherkassy region by the method of linear classification (n = 566) has been carried out. The results of the evaluated animals by the 100-score system indicate that within the group of traits, the average level of assessment is "good with the plus". The animals have been differed by the good development of group features characterizing the dairy type (82.4 score), body condition (83.5 score), limbs (82.8 score), udder (82.7 score) and overall score (82.8 score). The degree of development 18 descriptive traits of the exterior of cows, has been predicted by the method of linear classification, indicates their significant intraherd variability. Animals have the moderate height, deep body and angularity. The rump angle, the angle of hock joint and the teats length, according to the variability of scores in the range of 17.8–22.4%, have an average optimal development. The level of scores for the rear width (5.9 score), attachment of the fore (6.3 score) and the rear parts (6.0 score) of the udder testifies to their good development. The body structure of the cows-firstborn has a sufficient description of the type traits that determine their milk yield. At the present stage of selection and breeding work due to the use of bull-sires different origins and breeding value on the local population livestock with significant genotype diversity, the degree of influence each of the hereditary factors in the overall variability of linear features has a scientific and practical significance. In our studies, the force of influence conditional bloodiness of the Holstein mother's breed in the overall fraction of variability of linear type traits within the exterior complexes and the overall assessment takes a significant percentage - from 24.9 to 31.5 with a high degree of reliability according to Fischer's criterion. Among the descriptive traits, the proportion of influence the conditional bloodiness of mother, which is confirmed by high statistical confidence, ranges from 14.4 to 19.8%, and refers to the traits important for breeding. The level of coefficients of influence the father's breeding value in the total phenotypic variability for some of the linear traits is high and reliable. First of all it concerns group traits of the exterior, the development of which is determined by the pedigree value of father by 37.1–41.8%, and the overall assessment of type – by 46.6%. The coefficients of influence father's breeding value in most of the descriptive traits have high reliability (P < 0,001). The coefficients of the force of influence father, depending on the heredity of Holstein for the linear traits of almost the same level as his pedigree value. Since in this case the organized factor is purebreed Holstein and crossbreed bulls-sires of domestic selection, the positive role of Holstein heredity in improving the exterior type of cows has been traced realistically. The necessity of linear breeding, as an effective method in the system of dairy cattle breeding, has been substantiated by reliable values of the coefficients of the force of influence of father's line on the linear traits of offspring (3.4–29.5%). Despite the significant variability of coefficients of the force of influence on the linear traits, most of them have a high level of reliability within the evaluated body parts important for selection. The effect of cows belonging to the maternal line on the development of features of the body structure is insignificant and unreliable (5.3–9.2%). In the process of breeding aimed at improving cows of dairy herd by the exterior type, the pedigree value of parents has been assessed according to the method of linear classification of their daughters and their belonging to perspective genealogical formations.


2013 ◽  
Vol 3 (12) ◽  
pp. 462 ◽  
Author(s):  
Alvaro L. Ronco ◽  
Eduardo De Stéfani

Since its discovery in the beginning of the XXth century, squalene has been recognized as an important link in metabolic pathways. More recently, it has been further recognized as an intermediate step in the biosynthesis of cholesterol. Its well known antioxidant capability, together with its ability to protect skin, improve the immune system, and modulate the lipid profile, confer a high potential to this natural substance, which is spread all across the body structure, though mainly in the epithelial tissues, and in particular the skin sebum. This review will focus mainly on its major properties, which are related to anticancer properties, the maintenance of the oxidation/antioxidation balance, and its antiaging capabilities. Although the substance was originally obtained from shark liver oil, it is currently possible to obtain useful amounts from vegetable sources like extra virgin olive oil, therefore avoiding the dependence on capturing the aforementioned animal species. Recognized as one of the key components of the Mediterranean dietary style, squalene is necessary to adequately manage oxygen and its derivatives in every cell of the body. Key words: aging, antioxidants, cancer, cholesterol, diet, olive oil, squalene


2020 ◽  
Vol 49 (6) ◽  
pp. 71-78
Author(s):  
О. M. Bonina ◽  
Е. А. Serbina

The results of studying the body structure of trematode cercariae of the families Opisthorchiidae and Notocotylidae and the features of their development in Western Siberia are presented. The data of long-term (1994–2019) studies on the spread of these pathogens of dangerous parasitic diseases in humans and animals are analyzed and summarized. The studies were conducted according to generally accepted methods in parasitology and hydrobiology. The species affi  liation of trematodes was determined in laboratory conditions on mature cercariae that independently left the shells of the host mollusks Bithynia tentaculata and B. troscheli. It was noted that the trematodes of the Opisthorchiidae and Notocotylidae families at the cercaria stage have the following similar features: a simple tail, pigmented eyes, and one oral sucking cup. Diagnosis of trematode cercariae of Opisthorchiidae and Notocotylidae families is possible by the following signs: the tail of the opisthorchis cercaria has a swimming membrane and is 2 times longer than the body, the tail of the notocotylid has no swimming membrane and is approximately equal in length to the body. Opisthor-chis cercariae have two pigment eyes, notocotilids – three. In the life cycle of opisthorchis, there are two intermediate hosts (bitinia and fi  sh), in the notocotylid cycle, one (bitinia). Opisthorchis cercariae have penetration glands, but notocotylids do not; the maximum daily emission of opisthorchis cercariae is ten times higher than that of notocotylids (6672 and 422 cercariae, respectively). The ability to diagnose opisthorchis and notocotilid at the cercaria stage allows the identifi cation of local foci of epidemiologically and epizootically dangerous diseases.


2021 ◽  
pp. 1-11
Author(s):  
Min Zhang ◽  
Haijie Yang ◽  
Pengfei Li ◽  
Ming Jiang

Human pose estimation is still a challenging task in computer vision, especially in the case of camera view transformation, joints occlusions and overlapping, the task will be of ever-increasing difficulty to achieve success. Most existing methods pass the input through a network, which typically consists of high-to-low resolution sub-networks that are connected in series. Still, during the up-sampling process, the spatial relationships and details might be lost. This paper designs a parallel atrous convolutional network with body structure constraints (PAC-BCNet) to address the problem. Among the mentioned techniques, the parallel atrous convolution (PAC) is constructed to deal with scale changes by connecting multiple different atrous convolution sub-networks in parallel. And it is used to extract features from different scales without reducing the resolution. Besides, the body structure constraints (BC), which enhance the correlation between each keypoint, are constructed to obtain better spatial relationships of the body by designing keypoints constraints sets and improving the loss function. In this work, a comparative experiment of the serial atrous convolution, the parallel atrous convolution, the ablation study with and without body structure constraints are conducted, which reasonably proves the effectiveness of the approach. The model is evaluated on two widely used human pose estimation benchmarks (MPII and LSP). The method achieves better performance on both datasets.


2021 ◽  
Author(s):  
Junfeng Xue ◽  
Jiehao Li ◽  
Zhihua Chen ◽  
Shoukun Wang ◽  
Junzheng Wang ◽  
...  

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