Locomotion Cycle Research Articles

On the locomotion of the slider within a self-adaptive beam–slider system

A beam–slider system is considered whose passive self-adaption relies on an intricate locomotion process involving both frictional and unilateral contact. The system also exploits geometric nonlinearity to achieve broadband efficacy. The dynamics of the system take place on three distinct time scales: On the fast time scale of the harmonic base excitation are the vibrations and the locomotion cycle. On the slow time scale, the slider changes its position along the beam, and the overall vibration level varies. Finally, on an intermediate time scale, strong modulations of the vibration amplitude may take place. In the present work, first, an analytical approximation of the beam’s response on the slow time scale is derived as function of the slider position, which is a crucial prerequisite for identifying the main drivers of the slider’s locomotion. Then, the most important forms of locomotion are described and approximations of their individual contribution to the overall slider transport are estimated. Finally, the theoretical results are compared against numerical results obtained from an experimentally validated model.

Multi-Locomotion Design and Implementation of Transverse Ledge Brachiation Robot Inspired by Sport Climbing.

Brachiation robots mimic the locomotion of bio-primates, including continuous brachiation and ricochetal brachiation. The hand-eye coordination involved in ricochetal brachiation is complex. Few studies have integrated both continuous and ricochetal brachiation within the same robot. This study seeks to fill this gap. The proposed design mimics the transverse movements of sports climbers holding onto horizontal wall ledges. We analyzed the cause-and-effect relationship among the phases of a single locomotion cycle. This led us to apply a parallel four-link posture constraint in model-based simulation. To facilitate smooth coordination and efficient energy accumulation, we derived the required phase switching conditions as well as joint motion trajectories. Based on a two-hand-release design, we propose a new style of transverse ricochetal brachiation. This design better exploits inertial energy storage for enhanced moving distance. Experiments demonstrate the effectiveness of the proposed design. A simple evaluation method based on the final robot posture from the previous locomotion cycle is applied to predict the success of subsequent locomotion cycles. This evaluation method serves as a valuable reference for future research.

Biomechanical energetics of terrestrial locomotion in California sea lions (Zalophus californianus).

Pinnipedia, an order of semi-aquatic marine mammals, adapted a body design that allows for efficient aquatic locomotion but limited terrestrial locomotion. Otariids, like the California sea lion (Zalophus californianus), have enlarged forelimbs and can bring their hindlimbs under the body to locomote quadrupedally on land, but phocids (true seals) have reduced forelimbs and are unable to bring their hindlimbs beneath them during terrestrial locomotion. Because of these differences, phocids are expected to have greater energetic costs when moving on land compared with otariids. The mechanical costs of transport (COT) and power outputs of terrestrial locomotion were first obtained from one male and two female adult California sea lions through video recording locomotion sequences across a level runway. The center of mass, along with six other anatomical points, were digitized to obtain variables such as velocity (V), amplitude of heave (A) and the frequency (f) of oscillations during the locomotion cycle. These variables represent the principal parameters of a biomechanical model that computes the power output of individuals. The three California sea lions in this study averaged a power output of 112.04 W and a COT of 0.63 J kg-1m-1. This footage was compared against video footage previously recorded of three phocid species (harbor seal, gray seal and northern elephant seal). Power output and mechanical COT were compared for all four pinniped species by tracking the animals' center of mass. The quadrupedal gait of sea lions showed lower vertical displacements of the center of mass, and higher velocities compared with the terrestrial gait of phocids. Northern elephant seals, gray seals and harbor seals showed significantly higher COT and power outputs than the sea lions. California sea lions locomote with lower energetic costs, and thus higher efficiency compared with phocids, proving that they are a mechanically intermediate species on land between terrestrial mammals and phocids. This study provides novel information on the mechanical energy exerted by pinnipeds, particularly California sea lions, to then be used in future research to better understand the limitations of these aquatic mammals.

Robust Design and Evaluation of a Novel Modular Origami-Enabled Mobile Robot (OSCAR)

Abstract This article presents critical design modifications for an Origami-enabled Soft Crawling Autonomous Robot (OSCAR). OSCAR’s upgraded design mitigates motion uncertainties, which often plague soft robots. More specifically, we present a design that mitigates motion uncertainties caused by the feet interaction with the ground and uncertainties in the assembly procedures and actuators’ control. The new design has a robust and repeatable locomotion cycle that reaches more than 95% of its ideal, analytically predicted locomotion cycle. OSCAR’s performance is experimentally validated using two case studies, namely, navigation in a 2D environment with static obstacles and coupled locomotion of two docked OSCAR segments. Results from the first case study demonstrate OSCAR’s accurate and robust path following performance across multiple trials and experiments. Results from the second case study show the successful and repeatable earthworm-inspired locomotion of two docked OSCAR segments. The second case study demonstrates OSCAR’s modular design. OSCAR’s modified design, along with the reduced motion uncertainty, allows for operation where individual segments can operate alone or while docked to other segments. The repeatable and modular OSCAR design presented in this study expands the operational envelope for origami-enabled robots and allows their deployment in various applications.

Data integration and evolutionary analysis of long non-coding RNAs in 25 flowering plants

BackgroundLong non-coding RNAs (lncRNAs) play vital roles in many important biological processes in plants. Currently, a large fraction of plant lncRNA studies center at lncRNA identification and functional analysis. Only a few plant lncRNA studies focus on understanding their evolutionary history, which is crucial for an in-depth understanding of lncRNAs. Therefore, the integration of large volumes of plant lncRNA data is required to deeply investigate the evolution of lncRNAs.ResultsWe present a large-scale evolutionary analysis of lncRNAs in 25 flowering plants. In total, we identified 199,796 high-confidence lncRNAs through data integration analysis, and grouped them into 5497 lncRNA orthologous families. Then, we divided the lncRNAs into groups based on the degree of sequence conservation, and quantified the various characteristics of 756 conserved Arabidopsis thaliana lncRNAs. We found that compared with non-conserved lncRNAs, conserved lncRNAs might have more exons, longer sequence length, higher expression levels, and lower tissue specificities. Functional annotation based on the A. thaliana coding-lncRNA gene co-expression network suggested potential functions of conserved lncRNAs including autophagy, locomotion, and cell cycle. Enrichment analysis revealed that the functions of conserved lncRNAs were closely related to the growth and development of the tissues in which they were specifically expressed.ConclusionsComprehensive integration of large-scale lncRNA data and construction of a phylogenetic tree with orthologous lncRNA families from 25 flowering plants was used to provide an oversight of the evolutionary history of plant lncRNAs including origin, conservation, and orthologous relationships. Further analysis revealed a differential characteristic profile for conserved lncRNAs in A. thaliana when compared with non-conserved lncRNAs. We also examined tissue specific expression and the potential functional roles of conserved lncRNAs. The results presented here will further our understanding of plant lncRNA evolution, and provide the basis for further in-depth studies of their functions.

The development of a representative multidimensional transient duty cycle for in-service switcher locomotives

Switcher locomotives operate in railway yards where they shunt railcars and assemble trains. Shunting railcars requires frequent aggressive acceleration and deceleration events in order for the locomotive to push or pull railcars onto specific tracks. As a result, switcher locomotives rarely sustain tractive power for any significant period of time. Given that all switchers in North America rely on diesel-electric propulsion; the result is rapid and frequent transitions in engine power leading to a very low engine efficiency and high levels of emissions. Any attempt to quantify or remedy these issues will face a lack of a representative profile or test cycle. A locomotive duty cycle is a breakdown of time spent at each power level of the locomotive’s engine. A major drawback of current duty cycles is that they only account for steady power. Such cycles are not representative of real switcher locomotive operation. This paper presents a real-world transient duty cycle for switcher locomotives that accounts for the rapid power transitions and is argued to be more statistically representative of actual operations. The methodology adopted relies on real-time data collection, microtrip based trip segmentation, and a finite mixture model-based clustering algorithm. Measurements were collected on a EMD 16-645 GP9 locomotive. The duty cycle developed herein is representative of switching operations in Southern Railway of British Columbia’s New Westminster Yard as an example of the methodology which can be repeated in other cases as well.

A common role for astrocytes in rhythmic behaviours?

Astrocytes are a functionally diverse form of glial cell involved in various aspects of nervous system infrastructure, from the metabolic and structural support of neurons to direct neuromodulation of synaptic activity. Investigating how astrocytes behave in functionally related circuits may help us understand whether there is any conserved logic to the role of astrocytes within neuronal networks. Astrocytes are implicated as key neuromodulatory cells within neural circuits that control a number of rhythmic behaviours such as breathing, locomotion and circadian sleep-wake cycles. In this review, we examine the evidence that astrocytes are directly involved in the regulation of the neural circuits underlying six different rhythmic behaviours: locomotion, breathing, chewing, gastrointestinal motility, circadian sleep-wake cycles and oscillatory feeding behaviour. We discuss how astrocytes are integrated into the neuronal networks that regulate these behaviours, and identify the potential gliotransmission signalling mechanisms involved. From reviewing the evidence of astrocytic involvement in a range of rhythmic behaviours, we reveal a heterogenous array of gliotransmission mechanisms, which help to regulate neuronal networks. However, we also observe an intriguing thread of commonality, in the form of purinergic gliotransmission, which is frequently utilised to facilitate feedback inhibition within rhythmic networks to constrain a given behaviour within its operational range.

Организация управления жизненным циклом отечественных локомотивов

The service system for managing the life cycle of locomotives faces the problem of obtaining objective information about the technical condition of the locomotive and its operation. Designers of equipment and the locomotive as a whole, locomotive-building plants, service companies, locomotive repair plants and the operating organization have their own information systems that are not connected to each other. It is proposed to create a cross-platform management system for the locomotive life cycle database with the collection of information from all information systems at all stages of the locomotive life cycle with the appropriate management organization, which is described in the article. Information about the structure of the locomotive equipment, possible suppliers and maintenance regulations (MRO) is formed at the design stage. Information on the numbers and suppliers of installed equipment and test results is generated at the stage of locomotive manufacturing. In operation, the mileage of the locomotive, the ton-kilometer work, and, if possible, the electricity consumption are recorded. The MRO system registers the types and volumes of work, their duration and cost, and the spare parts and materials used. Equipment replacement is also registered. Separately, the reasons for failures and super-cycle work are analyzed. As a result, the database is formed for multi-factor analysis of the reasons for the low reliability of locomotives, the high cost of the life cycle. Corrective measures are being developed.

Improvement of the locomotive life cycle support system

Improvement of the locomotive life cycle support system

A snake robot for locomotion in a pipe using trapezium-like travelling wave

Snake robots are a suitable solution for various types of applications, especially in rough terrain or hardly accessible areas such as, for example, pipes. This article deals with a snake robot moving in a pipe using a so-called trapezium-like travelling wave. In this paper, we present a mathematical model of locomotion of the snake robot in a pipe of rectangular cross-section. Subsequently, we designed a control algorithm using a trapezium-like travelling wave. Within the control algorithm we introduced the so-called motion matrix of a trapezium-like travelling wave that contains information about the vector of generalized variables at any point of the locomotion cycle. The paper also presents a simulation model in MATLAB R2019b interfacing with CoppeliaSim V4.0.0. Furthermore, in our research we have developed an experimental snake robot with the purpose to verify the derived mathematical model, control algorithm and simulation model. Experimental results show the influence of certain parameters of the trapezium-like travelling wave on locomotion properties, such as the travelled distance or the average speed of the snake robot passing through a pipe. In the final part of this paper, experimental results are discussed and key elements of the proposed control algorithm are highlighted.

377 Validation and improvement of a monitoring system overtime and its overall capabilities

Abstract Automated animal monitoring is a growing segment in animal agriculture. These technologies capture biometric data from numerous parameters such as facial recognition, rumination, body temperature, and animal movement. The goal of automated animal monitoring technologies is to provide a 24 h perspective on an individual animal. These devices can offer valuable information pertaining to animal health, location, locomotion, animal behavior, phenotypic traits, and reproductive cycles. Devices collect data in various forms, such as counting steps, G.P.S. coordinates, triangulation, or XYZ coordinates. Raw data (e.g. step counts, XYZ coordinates) are then analyzed with proprietary algorithms to provide information in a usable format to the consumer. However, the development of these algorithms require thousands of hours of observation. For example, thorough visual observation of individual animal behaviors (e.g. rumination and eating time) can be identified based upon accelerometer movement. However, these calculated behaviors must then be validated through observation to optimize accuracy. Accelerometer-based devices are common in the dairy industry and growing in popularity in the beef industry for monitoring health and detecting estrus. Twenty-four-hour observation provides livestock producers greater insight than does once or twice daily observations. However, the usefulness or reliability of a technology requires evaluation of outcomes based on sensitivity and specificity of the test. The choice to optimize sensitivity or specificity is dependent on the desired outcome of the end user. For example, by increasing sensitivity in an animal health monitoring system, more truly ill animals will be identified, but more false positives will be generated, resulting in more animal treatments and elevated treatments costs. Conversely, increasing specificity, sick animals will be missed, but treatment costs will be reduced. Ultimately, developing an automated animal monitoring system that meets consumer expectation is the goal; however, information interpretation and evaluation will still be necessary by the end user.

Comparison of Z-N and PSO based tuning methods in the control strategy of prosthetic limbs application

The aim of the study is to compare Ziegler-Nichols (Z-N) and Particle Swarm Optimization (PSO) based tuning methods for controller tuning in the driving mechanism of prosthetic limbs. By adopting suitable control strategies like P, PI and PID in the driving system, the positioning of knee and hip joints can be attained in the ideal time of 1.4s for completing one locomotion cycle. The gain constants (KP , KI , and KD) of the controllers were tuned manually and also using Z-N and PSO; thereby appropriate constants were determined so that the joints could be moved to the desired position. The performance of P, PI, and PID controllers were compared and PID was identified as the ideal control strategy which exhibited least error and good stability. It was observed that the conventional Z-N method produced a big overshoot, and so a modern approach called PSO was employed to enhance its capability. The PSO based PID controller optimization resulted in less overshoot as well as it helped in optimizing the gain constants so as to improve the stability of the system when compared to the classical method.

Exploring the attachment of the Mediterranean medicinal leech (Hirudo verbana) to porous substrates.

Haematophagous ectoparasites must ensure a reliable hold to their host during blood meals and, therefore, have evolved a broad spectrum of versatile and effective attachment mechanisms. The Mediterranean medicinal leech (Hirudo verbana), for example, uses suction on both smooth and textured air-tight substrates. However, preliminary studies showed that H. verbana is also capable of attaching itself to air-permeable substrates, where suction does not work. Using high-speed videography and mechanical tests, we comparatively investigated the attachment of H. verbana on both smooth and textured air-tight as well as on porous artificial substrates, also considering the influence of mucus on sucker surfaces. In general, the leech-specific locomotion cycle did not differ between the tested surfaces, and the leeches were able to reliably attach to both air-tight and porous substrates. From our results, we conclude that suction is presumably the primary attachment mechanism of H. verbana. However, secondary mechanisms such as mechanical interlocking with surface asperities and pores or capillary forces occurring at the interface between the mucus-covered suckers and the substratum are also employed. In any case, the rich repertoire of applicable attachment principles renders the organs of H. verbana functionally highly resilient.

Natural gas as a transitional solution for railway powering systems: Environmental and economic assessment of a fuel cell based powering system

This study presents a comprehensive environmental impact and economic assessment of the use of natural gas in potentially cleaner locomotives. An integrated direct methane-solid oxide fuel cell powering system is proposed and analyzed using energy and exergy methods. The system reaches the optimum energy and exergy efficiencies of 85.8% and 83.3%, respectively. Comparing the operation of this integrated system to a currently used diesel-electric engine for an intercity passenger locomotive duty cycle, the use of methane in a solid oxide fuel cell powering system reduces CO2 emissions by 58.4%, and fuel costs drop by a factor of 3.4. In general, a total of 10.6% increase in power production by the cascaded Rankine cycles helps reduce the CO2 emissions by 4.4%. As a result, the use of natural gas in rail transportation has clear and significant environmental and economic advantages over diesel. Also, the implementation of solid oxide fuel cell-based powering systems is justified environmentally and economically, and future researchers should build prototypes for demonstration purposes of future clean locomotives.

Design of a Self-Reconfigurable Drain Mapping Robot With Level-Shifting Capability

Nature has always been an inspiration for engineers and designers to have technological inventions. The postures, locomotion and gait cycles of animals are usually smooth, dynamically stable, and highly adaptable in an unknown terrain. Based on a giraffe's leg folding pattern, we develop a quadruped hybrid drain mapping robot with modular sub-systems, four bar inversion mechanism based legs and bi-directional rolling wheel, named, Tarantula-II. The platform undergoes self-reconfiguration and achieves variable height and width, which in turn helps in navigation in a drain with multiple level-shifts. This paper describes the key features of giraffe's limb, how the folding pattern of the limbs are implemented in the robot design. In addition, we discuss the detailed mechanical design of platform, the kinematics analysis of each leg, kinematics of the platform with respect to wheels, and structural analysis of the platform under different gait condition. Applying the kinematics formulation and posture correction algorithm, we verify the mobility and level shifting capability of the platform both in lab setting and drain environment.

Online assessment of the electric locomotive life cycle cost

The selection and supply of electric locomotives based on the life cycle contract requires a more thorough review of indicators of their effectiveness implemented in operation. This study examines the main operation indicators currently used: coefficients of operational availability, technical availability, intrinsic availability (instantaneous), availability of the locomotive fleet, performed ton-kilometer operation, and electric power consumption. However, these indicators are not comprehensive and do not provide an overall economic assessment of operation. For a comprehensive assessment of the effectiveness of operation of locomotives, an online calculation of the life cycle cost is proposed. This involves directly using operating and service data for its performance, and the calculation of an indicator — life cycle specific cost (LCSC). The online LCSC is a uniform criterion associated with the energy efficiency of the performed transportation, volume of the ton-kilometer operation, operation expenses, reliability of electric locomotive, and its equipment availability ratio (EAR). The LCSC analysis enables assessment of deviations of the operation effectiveness indicators from those planned, and determining a strategy for improvement of the electric locomotive. It helps to define peculiarities in the operation of an electric locomotive and to forecast its condition and potential properties. Additionally, the LCSC facilitates analyzing the condition of a group of electric locomotives when changing the operation technology (for example, operation starting with increased rolling stock weight), including assessment of the extent of economic benefits of fulfilled measures.Currently, scientists of the JSC “VNIIZhT” and specialists of LLC “Ural Locomotives” are conducting tests on the electric locomotives 2EC6 on the Oktyabrskaya railroad using the “Online LCC” server. This allows online analysis of information collected on the operation and servicing of locomotives under the life cycle contract, pro viding effective and prompt control of the electric locomotive fleet.

Inchworm-Inspired Soft Robot With Light-Actuated Locomotion

In this work, a light-actuated inchworm-inspired soft robot capable of directional locomotion has been proposed, developed, and characterized. The robot is designed and divided into three parts according to the functions during locomotion, which are the body, front leg, and back leg. The body of inchworm should provide contraction and stretching force. Thus, bilayer reduced graphene oxide and graphene oxide-polydopamine soft film is fabricated acting as robot body since it could implant light-induced deformation rapidly when stimulated. When applying near-infrared laser on it, bending would generate and unbending would take place after withdrawing laser, which imitates the longitudinal body muscle controlling contraction and stretching behavior of the inchworm during locomotion. Besides, robot legs are designed owning different heights and contact angles to the ground. Due to such structure, the directional movement could be realized. Then, by coordinating the body and two legs, the robot achieves a biomimetic inchworm gait. Experiments are carried out to characterize the robot body's light sensitivity as well as the robot's locomotive performance. As the experiment results showed, robot body bends at a speed of 17 °/s when laser is applied on it and the whole robot could realize forward locomotion mimicking inchworm by applying laser light periodically. The step length during one locomotion cycle could achieve 0.6 mm, which is 1/10 of body length.

Mechanical energetics and dynamics of uphill double-poling on roller-skis at different incline-speed combinations.

ObjectivesThe purpose of this study was to investigate the effect of different incline-speed combinations, at equal external power outputs, on the mechanics and energetics of the double-poling (DP) technique in cross-country skiing.MethodsFourteen elite male cross-country skiers performed treadmill DP on roller-skis at low, moderate, and high mean external power outputs (Pmean) up a shallow incline (5%, INC5), at which DP is preferred, and up a steep incline (12%, INC12), at which DP is not preferred. Speed was set to produce equal Pmean at both inclines. From recorded kinematics and dynamics, arm power (Parm) and trunk+leg power (PT+L) were derived, as were pole propulsion power (Ppole) and body mechanical energy perpendicular to the treadmill surface (Ebody⊥).ResultsOver a locomotion cycle, the arms contributed 63% to Pmean at INC5 but surprisingly only 54% at INC12 (P<0.001), with no effect of Pmean (P = 0.312). Thus, the trunk and legs contributed substantially to Pmean both at INC5 (37%) and INC12 (46%). At both inclines, PT+L generation during the swing phase increased approximately linearly with Pmean, which increased Ebody⊥. Within the poling phase, ~30–35% of the body energy which was developed during the preceding swing phase was transferred into propulsive pole power on both inclines. At INC5, the amount of negative PT+L during the poling phase was larger than at INC12, and this difference increased with Pmean.ConclusionsThe considerable larger amount of negative PT+L during poling at INC5 than at INC12 indicate that the legs and trunk generate more power than ‘necessary’ during the swing phase and thus must absorb more energy during the poling phase. This larger surplus of PT+L at INC5 seems necessary for positioning the body and poles so that high Parm generation can occur in a short time. At INC12, less Parm is generated, probably due to less advantageous working conditions for the arms, related to body and pole positioning. These incline differences seem linked to shorter swing and longer poling times during steep uphill DP, which are due to the increased influence of gravity and slower speed at steep inclines.

CHOOSING THE SYSTEM OF LOCOMOTIVE MAINTENANCE IN VIEW OF THE EFFECT OF DEPENDENT FAILURES

Purpose. Improving the efficiency of the use of locomotives by choosing a rational maintenance system that takes into account the assessment of the effect of dependent failures on the cost of their life cycle is the main purpose of this paper. Methodology. The relevance of introducing LCC (Life Cycle Cost) approaches in locomotive facilities is explained by the introduction of new locomotives with on-board control and diagnostic systems, as well as the development of the theory of traction rolling stock maintenance systems. The cost of a locomotive as a traction unit ceases to be the determining factor. This is because the locomotive maintenance and repair cost for the entire period of its operation is much higher than the initial cost of the locomotive. The paper analyses the existing approaches to managing the cost of the life cycle of locomotives at the stages of selecting, updating, upgrading and operating the traction rolling stock. The necessity of improving the methods for assessing the degree of influence of reliability indicators of locomotive assemblies on the choice of the maintenance system and the cost of the locomotive life cycle is substantiated. Findings. It is proposed to use the concept of «the effect of dependent failures» when calculating the cost of locomotive renewal after unscheduled repairs and its life cycle cost. We improved the methods for determining the cost of unscheduled repairs, taking into account dependent failures and the coefficient of assessment of the effect of dependent node failure on the locomotive maintenance system. The proposed coefficient will determine the nodes, the failure of which affects the renewal cost more than their nominal value. It will also help to take into account the probable losses due to node failure during the development and adjustment of the locomotive maintenance system. Originality. For the first time, it is proposed to use the concept of the effect of dependent failures to calculate the locomotive renewal cost when performing unscheduled repairs, as well as the locomotive life cycle cost. Practical value. The improved calculation method for determining the cost of unplanned repairs with account taken of dependent failures can be used to compare and evaluate different variants of the locomotive maintenance system and to develop the locomotive diagnostic systems.

Control Synergies for Rapid Stabilization and Enlarged Region of Attraction for a Model of Hopping.

Inspired by biological control synergies, wherein fixed groups of muscles are activated in a coordinated fashion to perform tasks in a stable way, we present an analogous control approach for the stabilization of legged robots and apply it to a model of running. Our approach is based on the step-to-step notion of stability, also known as orbital stability, using an orbital control Lyapunov function. We map both the robot state at a suitably chosen Poincaré section (an instant in the locomotion cycle such as the mid-flight phase) and control actions (e.g., foot placement angle, thrust force, braking force) at the current step, to the robot state at the Poincaré section at the next step. This map is used to find the control action that leads to a steady state (nominal) gait. Next, we define a quadratic Lyapunov function at the Poincaré section. For a range of initial conditions, we find control actions that would minimize an energy metric while ensuring that the Lyapunov function decays exponentially fast between successive steps. For the model of running, we find that the optimization reveals three distinct control synergies depending on the initial conditions: (1) foot placement angle is used when total energy is the same as that of the steady state (nominal) gait; (2) foot placement angle and thrust force are used when total energy is less than the nominal; and (3) foot placement angle and braking force are used when total energy is more than the nominal.