341 research outputs found
Yumuşak omurgalı çok bacaklı modüler minyatür robotun tasarımı, kontrolü, modellenmesi ve lokomosyon analizi
No full textCataloged from PDF version of article.Includes bibliographical references (leaves 108-116).Soft Modular Legged roBot (SMoLBot) is a legged, foldable, modular, miniature robot with soft backbones. SMoLBot’s body and locomotion mechanisms are folded out of acetate sheets and its compliant connection mechanisms are molded from Polydimethylsiloxane (PDMS). High maneuverability and smooth walking pattern can be achieved in miniature robots if high stiffness kinematic parts are connected with compliant components, providing the robot structural compliance and better adaptability to different surfaces. SMoLBot is exploiting features from origami-inspired robots and soft robots, such as low weight and low cost foldable rigid structures and adaptable soft connection mechanisms made of PDMS. Every single module in SMoLBot is actuated and controlled by two separate DC motors, that enable gait modification and a higher degree of freedom on controlling the motion and body undulation of the robot in turning and rough terrain locomotion. Each module has 44.5 mm width, 16.75 mm length, and 15 mm height, which is approximately the same size as two DC motors and a Li-Po battery.
The dynamic formulation of SMoLBot is obtained using Newton-Euler formulation and it depends on the physical parameters of the contact and closed-chain kinematic analysis of the feet. The dynamic model framework is proposed by determining the dynamic locomotion parameters of each module as an individual system, as well as, considering the dynamics of the whole robot; i.e. the robot is modeled as one system and modules are considered to be set of flexible links connected to each other, within this system. Kinematic constraints among these modules are obtained by considering the types of backbones integrated in the robot. Various types of backbones are used within the experiments that are
classified into two groups: rigid, and compliant backbones. Experimental results of SMoLBot running/walking with different symmetrical and asymmetrical gates validate the dynamic model presented in this thesis. Additional to the dynamic model, the effect of the backbone stiffness on the locomotion of the legged miniature modular robots with multiple numbers of modules is studied. Analyses comparing the velocity of SMoLBot with different numbers of modules and different types of backbones are presented using the proposed dynamic model. The results indicate that there is an optimum torsional stiffness of the backbone for a legged miniature modular robot that maximizes the robot’s translational velocity. Additionally, we can show that, for a given backbone stiffness or a specific range of compliance between the modules, there is an optimum number of feet for the miniature robots.
Furthermore, in this thesis, a locomotion study that investigates the motion patterns of the running/walking multi-legged modular miniature robots with soft module connections, is conducted. The locomotion study is done using the presented dynamic model and results are verified using SMoLBot. The optimum feet sequence and the optimum stride length of a multi-legged robot are derived using the locomotion analyses, and the dynamic and kinematic formulations. The optimum gait analysis of the multi-legged SMoLBots represents different but unique feet contact sequence patterns for each robot with a different module number and diverse ranges of compliance between the modules. Furthermore, analysis considering the effect of various feet failure cases on the locomotion of a multilegged robot with soft/rigid backbones, is conducted. This study investigates the locomotion behavior of a legged miniature robot with different combinations of the non-functioning feet. Additionally, a case-sensitivity study of an n-legged SMoLBot’s locomotion on its individual modules during the operation, is also conducted. This study investigates the modular robot’s locomotion with multiple different failure cases where each particular case only considers the effect of an individual module failure on the overall motion of the robot, while the gate is not altered.by Nima Mahka
Author Correction: The fusion–fission optimization (FuFiO) algorithm (Scientific Reports, (2022), 12, 1, (12396), 10.1038/s41598-022-16498-4)
No full textThe original version of this Article contained an error in the spelling of the author Nima Darabi which was incorrectly given as Nima Darabai. The Article also contained an error in the Equation in the Analyses based on competitions on evolutionary computation (CEC) section, under the subheading ‘Computational time and complexity analyses’ where “ O(FuFiO) ” was incorrectly given as “ O(FFO)”
A framework for dynamic modeling of legged modular miniature robots with soft backbones
No full textIn this work, the dynamics of ”n” legged modular miniature robots with a soft body is modeled. The dynamic formulation is obtained using Newton–Euler formulation that depends on the contact parameters and the feet closed-chain kinematic analysis. The dynamic model determines the locomotion parameters of each module as an individual system as well as the dynamics of the whole robot in a 3D space; i.e., the robot is modeled as one system, and modules are considered to be sets of flexible links connected within this system. Kinematic constraints among these modules are obtained by considering the type of backbone integrated into the modular robot. Various types of backbones are used that are classified into three groups: rigid, only torsional, and soft. The model is verified using SMoLBot, an origami-inspired miniature robot made of multiple modules and soft/rigid backbones. Additional to the dynamic model, the effect of different sets of design parameters on the locomotion of the legged soft-bodied modular miniature robots is studied. Analyses comparing the velocity of SMoLBot with a different number of modules and various types of backbones are presented using the proposed dynamic model. Our results show the existence of an optimum backbone torsional stiffness for legged miniature modular robots and an optimum number of legs for a given backbone stiffness that maximizes the robot’s velocity. In this research, presented results and locomotion study show that the robot’s design should be iteratively improved based on specific optimum goals for exclusively defined task to satisfy the operational needs
Gait and locomotion analysis of a soft-hybrid multilegged modular miniature robot
No full textThe locomotion performance of the current legged miniature robots remains inferior compared to even the most simple insects. The inferiority has led researchers to utilize biological principles and control in their designs, often resulting in improved performance and robot capabilities. Additionally, optimizing the locomotion patterns compatible with the robot's limitations (such as the gaits achievable by the robot) improves the performance significantly and results in a robot operating with its maximum capabilities. This paper studies the locomotion characteristics of running/walking n-legged modular miniature robots with soft or rigid module connections. The locomotion study is done using the presented dynamic model, and the results are verified using a legged modular miniature robot with soft and rigid backbones (SMoLBot). The optimum foot contact sequences for an n-legged robot with different compliance values between the modules are derived using the locomotion analyses and the dynamic and kinematic formulations. Our investigations determine unique optimum foot contact sequences for multi-legged robots with different body compliances and module numbers. Locomotion analyses of a multi-legged robot with different backbones operating with optimum gaits show two main motion characteristics; the rigid robots minimize the number of leg-ground contacts to increase velocity, whereas soft-backbone robots use a lift–jump–fall motion sequence to maximize the translational speeds. These two behaviors are similar between different soft-backbone and rigid-backbone robots; however, the optimal foot contact sequences are different and unpredictable
Application of dynamic Bayesian network to performance assessment of fire protection systems during domino effects
No full textThe propagation of fire in chemical plants â also known as fire domino effects - largely depends on the performance of add-on passive and active protection systems such as sprinkler systems, water deluge systems, emergency shut down and emergency blow down systems, fireproofing, and emergency response. Although such safety barriers are widely employed to prevent or delay the initiation or escalation of fire domino effects, their inclusion in the modeling and risk assessment of fire domino effects has hardly been taken into account. In the present study, the dynamic evolution of fire protection systems has been investigated qualitatively using event tree analysis. To quantify the temporal changes and their impact on the escalation of fire domino effects, a dynamic Bayesian network methodology has been developed. The application of the methodology has been demonstrated using an illustrative case study, considering a variety of fire scenarios, target installations, and firefighting systems
THE STRUCTURE OF AUTHORING IN NIMA YUSHIJ'S POETRY: A BAKHTINIAN READING
Get PDFThis thesis employs Mikhail Bakhtin’s notion of architectonics to examine the poetry of Nima Yushij, the father of “New Persian Poetry.” The architectonic structure of Nima’s poems presupposes an authorial position situated outside the whole of the work. Outsideness provides the author with the distance that is necessary for consummating the hero and all other elements inside the work’s environment in determinate spatial and temporal boundaries. As Bakhtin puts it, only in this way can the author acquire a surplus of seeing that is required for adopting a valuational stance in relation the hero and the work as a whole. To Bakhtin, the author’s valuational stance toward the hero is the essence of the aesthetic product. This valuational position vis-à-vis the other, which generates what Michael Holquist calls the “structure of authoring,” is enacted on multiple levels in Nima’s poems as the hero, and sometimes the narrator, also perform the authorial function vis-à-vis other characters inside the poem, i.e., fixing them in determinate spatial and temporal boundaries. Of course, from the author’s perspective, the hero and the narrator are also situated inside the poem and occupy specific horizons in its environment. In this sense, their authoring activity is not a precisely aesthetic activity. Nevertheless, Nima utilizes the hero and the narrator’ activity to foreground the structure of authoring inside the poem, to make its dynamics “viewable.” This is a point that I will try to elucidate fully in the course of this study.Doctor of Philosophy (PhD
History of Buddhism in Mongolia in Essay of Kensur Ngawang-Nima “Coverage of Classical Sources on History of Buddhism”
Get PDFThe article considers a part of the essay “Coverage of classical sources on the history of Buddhism” by the outstanding Buryat scholar Lama Kensura Ngawang-Nima, dedicated to the history of the spread of Buddhist teachings in Mongolia. Some biographical information of the author of the essay is introduced. The materials of the fragment under study are presented, on the basis of which we can say that the author divides the spread of Buddhism in Mongolia, like many researchers, into three stages. Secular and religious figures who played an important role in the spread and formation of Buddhism among the Mongols are noted in the article. It is indicated that when writing his historical treatise, Kensur Ngawang-Nima relied on the works of his famous predecessors, such as the 5th Dalai Lama Ngawang Lobsan Gyatso, Taranatha Gunga Nyingbo, Thukwan Chokyi Nyima, etc., and a part of the essay devoted to the history of Buddhism in Mongolia, based on the work “Golden Book / Altan Debter” by the famous Mongolian scholar Lama Shagdaryn Zava Damdin. The peculiarity of the historical treatise under study is that it is the only known and published work written by a Buryat in the Tibetan language in the genre of Tibetan historical literature — choichzhun
Smooth and Inclined Surface Locomotion and Obstacle Scaling of a C-Legged Miniature Modular Robot
No full textConference Name: 2021 IEEE 4th International Conference on Soft Robotics (RoboSoft)Date of Conference: 12-16 April 2021This work investigates the locomotion of a modular C-legged miniature robot with soft or rigid backbones on smooth, rough, and inclined terrain. SMoLBot-C is a C-legged miniature robot with soft or rigid backbones and foldable modules. The robot's climbing capabilities with soft and rigid C-legs and different backbones on rough terrain with obstacles and the robot's mobility on an inclined surface are compared. Our results show that the C-legged robot with soft legs and soft backbones can climb up to a higher obstacle, and walk on surfaces with higher inclination angles compared to the same robot with rigid legs and backbones, regardless of the number of modules (legs). Additionally, a velocity comparison study using SMoLBot-C operating at two different gaits is conducted. The results show that the robot with soft legs and compliant-I backbones operating with trot gait possesses the highest velocity compared to the other robots with similar leg numbers. Moreover, the effect of a compliant tail on the robot's locomotion on smooth and rough terrains is investigated, where the results show that the robot with the compliant tail is capable of walking on surfaces with higher inclination angles compared to the same robot without a tail. Furthermore, adding a tail to the two-legged SMoLBot-C doubles the maximum scalable obstacle height; the robot with a tail can climb up an obstacle 2 times higher than a module's height. Locomotion analysis in this manuscript provides a better insight into C-legged miniature robots' locomotion with soft or rigid legs while the modular connections' structural stiffness varies from rigid to soft
Special issue: Risk-based approaches to design and operation of process systems
No full textGreen Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Safety and Security Scienc
Security vulnerability assessment of gas pipelines using discrete-time Bayesian network
No full textSecurity of chemical and oil & gas facilities became a pressing issue after the terrorist attacks of 9/11, due to relevant quantities of hazardous substances that may be present in these sites. Oil & gas pipelines, connecting such facilities, might be potential targets for intentional attacks. The majority of methods addressing pipeline security are mostly qualitative or semi-quantitative, based on expert judgment and thus potentially subjective. In the present study, an innovative security vulnerability assessment methodology is developed, based on Discrete-time Bayesian network (DTBN) technique to investigate the vulnerability of a hazardous facility (pipeline in this study) considering the performance of security countermeasures in place. The methodology is applied to an illustrative gas pipeline in order to rank order the pipeline segments based upon their criticality.Safety and Security Scienc
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