High-speed Locomotion Research Articles

Automatic identification of differences in behavioral co-occurrence between groups

BackgroundRecent advances in sensing technologies have enabled us to attach small loggers to animals in their natural habitat. It allows measurement of the animals’ behavior, along with associated environmental and physiological data and to unravel the adaptive significance of the behavior. However, because animal-borne loggers can now record multi-dimensional (here defined as multimodal) time series information from a variety of sensors, it is becoming increasingly difficult to identify biologically important patterns hidden in the high-dimensional long-term data. In particular, it is important to identify co-occurrences of several behavioral modes recorded by different sensors in order to understand an internal hidden state of an animal because the observed behavioral modes are reflected by the hidden state. This study proposed a method for automatically detecting co-occurrence of behavioral modes that differs between two groups (e.g., males vs. females) from multimodal time-series sensor data. The proposed method first extracted behavioral modes from time-series data (e.g., resting and cruising modes in GPS trajectories or relaxed and stressed modes in heart rates) and then identified two different behavioral modes that were frequently co-occur (e.g., co-occurrence of the cruising mode and relaxed mode). Finally, behavioral modes that differ between the two groups in terms of the frequency of co-occurrence were identified.ResultsWe demonstrated the effectiveness of our method using animal-locomotion data collected from male and female Streaked Shearwaters by showing co-occurrences of locomotion modes and diving behavior recorded by GPS and water-depth sensors. For example, we found that the behavioral mode of high-speed locomotion and that of multiple dives into the sea were highly correlated in male seabirds. In addition, compared to the naive method, the proposed method reduced the computation costs by about 99.9%.ConclusionBecause our method can automatically mine meaningful behavioral modes from multimodal time-series data, it can be potentially applied to analyzing co-occurrences of locomotion modes and behavioral modes from various environmental and physiological data.

Dynamical determinants enabling two different types of flight in cheetah gallop to enhance speed through spine movement

Cheetahs use a galloping gait in their fastest speed range. It has been reported that cheetahs achieve high-speed galloping by performing two types of flight through spine movement (gathered and extended). However, the dynamic factors that enable cheetahs to incorporate two types of flight while galloping remain unclear. To elucidate this issue from a dynamical viewpoint, we developed a simple analytical model. We derived possible periodic solutions with two different flight types (like cheetah galloping), and others with only one flight type (unlike cheetah galloping). The periodic solutions provided two criteria to determine the flight type, related to the position and magnitude of ground reaction forces entering the body. The periodic solutions and criteria were verified using measured cheetah data, and provided a dynamical mechanism by which galloping with two flight types enhances speed. These findings extend current understanding of the dynamical mechanisms underlying high-speed locomotion in cheetahs.

Plasmonic-Enhanced Graphene Oxide-Based Aquatic Robot for Target Cargo Delivery.

The design and fabrication of light-actuated robots that can perform selective motions and targeted cargo delivery have attracted increasing interest in various fields. However, these robots' high-speed locomotion, precise direction control, and efficient actuation ability remain big challenges because of the relatively low photothermal efficiency, especially in the aquatic environment. This work proposes a plasmonic-enhanced graphene oxide (GO)-gold nanorod (Au NR)/calcium alginate (Ca-alginate) aquatic robot. The proposed robot design includes an independent power module (GO-Au NR layer) and a microscale cargo-loaded module (Ca-alginate layer). The plasmonic effect of Au NRs greatly improves the heat transfer efficiency, which in turn increases the temperature variation up to three times during the actuating process. This situation leads to a high traveling speed of the robot up to ∼35 mm/s. Benefiting from the high light-to-work efficiency, the position and posture of the proposed robot have good control in the aquatic environment. The robot is capable of programmable trajectory following, multirobot gathering, separation, and cooperation, providing an efficient solution for cargo delivery. Moreover, after releasing the cargo-loaded module to the target location, the power module can be easily actuated for collection, avoiding the potential side effects from the residual photothermal particles in conventional methods. The plasmonic-enhanced photothermal mechanism and independent module design offer a strategy for light-actuated aquatic robot development and would bring opportunities to further develop biomedical applications.

High-speed crawling-like locomotion robot using wobbling mass and reaction wheel

Aiming at generating steady and speedy locomotion on a slippery road, the authors have been investigating crawling-like locomotion robot using inner-wobbling effect. This paper discusses gaining transfer efficiency on an underactuated locomotion robot, which consists of an arc-shaped body with both a telescopic joint and a reaction wheel at the center of mass. First, we show the robot model, and then derive the equation of motion. A hierarchical control is also proposed to stabilize the dynamics. Second, we show the simulation results of a speedy locomotion on a slippery level surface. Finally, we discuss the stability of the reaction wheel motion.

Application of Quarter Car Model for Assessment of Attenuation Characteristics of Soil at Low Strain

Due to increase in population, industrialisation and a lack of space in the urban areas of Surat city in Gujarat (India), numerous buildings are being constructed in the vicinity of the railway tracks. The perspective is further aggravated by the proposal for a high-speed corridor (≥ 200 kmph) connecting two key Indian cities, Mumbai and Ahmedabad. These structures need to be evaluated for their susceptibility to the dynamic stresses induced by such high-speed locomotives. However, before the assessment of such dynamic stresses, geometrical and material damping properties of the in situ soil must be determined as the stresses induced in the structure also depend on the attenuation characteristics of the subsoil. With the objective to determine attenuation characteristics of the soil due to high-speed trains, the current study uses modelling capabilities of SAP2000 to prepare a vehicle-track-soil interaction model for dynamic analysis of the site in Surat city (India). A quarter car model (lumped mass model) prepared in SAP2000 environment is used to replicate CHR3-type high-speed train. The passage of train over the track structure is represented as a sinusoidal harmonic load. The study establishes that the statistical analysis of the attenuation of the waves is exponentially related to the distance from the source and follows the Bornitz equation. The frequency-independent damping ratio is computed considering near-field and far-field effect of induced vibration in the soil. Finally, the damping ratio and transmissibility are used to derive the critical velocity for the given track near the proposed site.

Lower complexity of motor primitives ensures robust control of high-speed human locomotion

Walking and running are mechanically and energetically different locomotion modes. For selecting one or another, speed is a parameter of paramount importance. Yet, both are likely controlled by similar low-dimensional neuronal networks that reflect in patterned muscle activations called muscle synergies. Here, we challenged human locomotion by having our participants walk and run at a very broad spectrum of submaximal and maximal speeds. The synergistic activations of lower limb locomotor muscles were obtained through decomposition of electromyographic data via non-negative matrix factorization. We analyzed the duration and complexity (via fractal analysis) over time of motor primitives, the temporal components of muscle synergies. We found that the motor control of high-speed locomotion was so challenging that the neuromotor system was forced to produce wider and less complex muscle activation patterns. The motor modules, or time-independent coefficients, were redistributed as locomotion speed changed. These outcomes show that humans cope with the challenges of high-speed locomotion by adapting the neuromotor dynamics through a set of strategies that allow for efficient creation and control of locomotion.

Locomotion on the edge: Structural properties of the third metacarpal in Thoroughbred and Quarter Horse racehorses and feral Assateague Island ponies.

The elongated, distally tapered limbs of horses are adapted for high-speed locomotion. Because these traits are artificially selected for in modern racehorses, they operate at a morphological extreme with a high risk of fracture. Racehorses are subject to different training and racing regimes depending on their breed and gait, and are therefore an interesting model to examine bone functional adaptation under variable biomechanically intense conditions. This study compares bone structural properties in the third metacarpal (MCIII) of Thoroughbred (n = 9) and Quarter Horse (n = 11) racehorses, using feral Assateague Island ponies (n = 6) as an untrained/unraced outgroup, to determine whether structural properties reflect variable racing and training regimes. Geometric section properties and bone mineral densities were determined using peripheral quantitative CT at two diaphyseal sites and through the distal epiphysis. Diaphyseal strength of the MCIII in all three breeds does not differ relative to body size, but in the mid-diaphyseal region Thoroughbreds have higher antero-posterior relative to medio-lateral bending strength than Quarter Horses, as well as higher bone mineral densities in left MCIII epiphyses (particularly in the lateral condyle). Interestingly, all breeds have lower bone mineral densities in the lateral versus medial condyle, an inherent structural feature that may influence predisposition to fracture when running around turns. Our results suggest that despite subtle differences in bone structure between different racehorse breeds, basic morphology of the third metacarpus is relatively similar among racing and non-racing horses, possibly reflecting intense selection (natural and artificial) across domestic equids for similar structural features within distal limb elements.

Viscoelastic legs for open-loop control of gram-scale robots

Gram-scale insects, such as cockroaches, take advantage of the mechanical properties of the musculoskeletal system to enable rapid and robust running. Engineering gram-scale robots, much like their biological counterparts, comes with inherent constraints on resources due to their small sizes. Resource-constrained robots are generally limited in their computational complexity, making controlled, high-speed locomotion a challenge, especially in unstructured environments. In this paper we show that embedding control into the leg mechanics of robots, similarly to cockroaches, results in predictable dynamics from an open-loop control strategy that can be modified through material choice. Tuning the mechanical properties of gram-scale robot legs promotes high-speed, stable running, reducing the need for active control. We utilize a torque-driven damped spring-loaded inverted pendulum model to explore the behavior and the design space of a spring-damper leg at this scale. The resulting design maps show the trade-offs in performance goals, such as speed and efficiency, with stability, as well as the sensitivity in performance to the leg properties and the control input. Finally, we demonstrate experimental results with magnetically actuated quadrupedal gram-scale robots, incorporating viscoelastic legs and demonstrating speeds up to 11.7 body lengths per second.

An Articulated Closed Kinematic Chain Planar Robotic Leg for High-Speed Locomotion

Abstract This paper presents the design, dynamic modeling, and integration of a single degree of freedom (DOF) robotic leg mechanism intended for tailed quadruped locomotion. The design employs a lightweight six-bar linkage that couples the hip and knee flexion/extension joints mechanically, requiring only a single degree of actuation. By utilizing a parametric optimization, a unique topological arrangement is achieved that results in a foot trajectory that is well suited for dynamic gaits including trot-running, bounding, and galloping. Furthermore, a singular perturbation is introduced to the hybrid dynamic framework to address the lack of robust methods that provide a solution for the differential algebraic equations (DAEs) that characterize closed kinematic chain (CKC) structures as well as the hybrid nature of legged locomotion. By approximating the system dynamics as ordinary differential equations (ODEs) and asymptotically driving the constraint error to zero, CKCs can adopt existing real-time model-based/model-predictive/hybrid-control frameworks. The dynamic model is verified through simulations and the foot trajectory was experimentally validated. Preliminary open-loop planar running demonstrated speeds up to 3.2 m/s. These advantages, accompanied by low-integration costs, warrant this leg as a robust, effective platform for future tailed quadruped research.

Shape-Morphing Wheel Design and Analysis for Step Climbing in High Speed Locomotion

The ability of wheeled mobile robots to overcome steps is often limited by wheel size. Enhancing the ability of mobile robots to overcome obstacles is essential for extending their operation area, and many previous attempts have been made by using transformable wheels, a linkage mechanism, and a spoke-type wheel-leg mechanism. In this study, we propose a shape-morphing wheel mechanism for step climbing at high speed. In the general case of low speed locomotion, a robot's wheels can be used normally. However, to overcome relatively large obstacles, the robot's wheels can extend its shape by using the proposed morphing mechanism with centrifugal force at high speed locomotion. Two modes of step climbing are analyzed that use kinetic energy conversion or impact on the steps. Detail design issues with comprehensive analyses results are presented. Results demonstrate that a robot with morphing wheels can climb a 46.67 mm obstacle at 1.82 m/s, which is 1.33 times larger than the wheel radius. We expect that this method can be applied to other locomotion modes of wheeled mobile robots.

HIGH-SPEED LOCOMOTIVE XBOM ONTOLOGY MODELING RESEARCH SUPPORTING MRO SEMANTIC KNOWLEDGE REPRESENTATION

The new trends of high-speed rail locomotive manufacturing set higher requirement for MRO knowledge representation and XBOM. Therefore, XBOM ontology modeling supporting MRO semantic knowledge representation has become an important research topic of the high speed railway locomotive manufacturing industry. This paper firstly expounds the model frame of high-speed locomotive XBOM ontology, then take the global ontology, the construction ontology and the maintenance plan ontology as examples; respectively carding and analyzing four approaches each ontology contains that class (concept), object, data attribute, and constraint rule and central with the supporting MRO semantic knowledge representation, the XBOM ontology conceptual model can be created; At last, High speed rail train MRO semantic knowledge representation was realized by using protégé4.1 ontology modeling of XBOM for high-speed locomotive

Mechanism Design of a Robotic Leg for Running Considering Radial Force Producibility and Tangential Mobility

A robotic leg of high-speed locomotion should be designed such that the mobility and the force producibility are maximized simultaneously. The mobility is crucial in a direction perpendicular to a line spanning from the head of upper limb to the tip of the lower limb, which is related to the rapid movement of the leg during swing. On the other hand, the force producibility is crucial in the same direction to the line, which is related to the thrust force of a leg in stance. In this paper, the tangential mobility and radial force producibility being defined mathematically, the mechanism design factors, i.e., an actuator configuration and a length ratio of upper limb and lower limb, are introduced, analysed, and determined for the leg to maximize both the tangential mobility and the radial force producibility. Applying the proposed design parameters, a robotic leg is fabricated, and the running motion is realized in experiment.

Estimation of leg stiffness using an approximation to the planar spring–mass system in high-speed running

Leg stiffness plays a critical role in legged robots’ speed regulation. However, the analytic solutions to the differential equations of the stance phase do not exist, of course not for the exact analytical solution of stiffness. In view of the challenge in dealing with every circumstance by numerical methods, which have been adopted to tabulate approximate answers, the “harmonic motion model” was used as approximation of the stance phase. However, the wide range leg sweep angles and small fluctuations of the “center of mass” in fast movement were overlooked. In this article, we raise a “triangle motion model” with uniform forward speed, symmetric movement, and straight-line center of mass trajectory. The characters are then shifted to a quadratic equation by Taylor expansion and obtain an approximate analytical solution. Both the numerical simulation and ADAMS-Matlab co-simulation of the control system show the accuracy of the triangle motion model method in predicting leg stiffness even in the ultra-high-speed case, and it is also adaptable to low-speed cases. The study illuminates the relationship between leg stiffness and speed, and the approximation model of the planar spring–mass system may serve as an analytical tool for leg stiffness estimation in high-speed locomotion.

Comparative morphological studies of the pelvic limb bones in ostrich (Struthio camelus), emu (Dromaius novaehollandiae), domestic fowl (Gallus gallus domesticus) and duck (Anas platyrhynchos domesticus)

Morphological and morphometrical study of pelvic limb bones from adult birds viz., ostrich (n=4), emu (n=6), domestic fowl (n=8) and duck (n=8) were carried out. Pubic symphysis was a distinctive feature of os coxae in ostrich. Medial surface of ilium was united to lumbosacral mass in ostrich and emu, whereas, only medial border made fusion in domestic fowl and duck. Post acetabular ilium was an elongated triangle in ostrich and emu, whereas, quadrilateral plate in domestic fowl and duck. Iliac fossae for kidneys were lacking in ostrich and emu. Ischium was a long rod in ostrich and emu. Ilio-ischiatic notch was present in ostrich and emu, while, ilio-ischiatic foramen was found in domestic fowl and duck. Caudal extremity of pubis was free in all the species studied excluding ostrich. Ostrich and emu exhibited a distinct pneumatic foramen on femur which was lacking in domestic fowl and duck. Length ratio of femur to tibiotarsus was 1:1.75, 1:1.88, 1:1.38 and 1:1.69 in ostrich, emu, domestic fowl and duck correspondingly. Lateral cnemial crest was a large tuberosity in ostrich; whereas, in other species it was a thick curved spine. Hypotarsus was in the form of spine in ostrich and emu. Bony spur of tarsometatarsus observed in male domestic fowl was lacking in the other species. Distal extremity showed two trochleae in ostrich, whereas, three trochleae, in the other species. Ostrich is the only didactyl bird with two digits. Emu possessed three digits, while, domestic fowl and duck possessed four. Our present study revealed pneumatic femur, longer tibiotarsus and tarsometatarsus and less number of digits in ostrich and emu. Reduction in number of phalanges also led to reduce the number of muscles and tendons associated to digits. The above mentioned features may aid ostrich and emu for high-speed locomotion.

A Hybrid Tracked-Wheeled Multi-Directional Mobile Robot

Abstract This paper presents the novel design and integration of a mobile robot with multi-directional mobility capabilities enabled via a hybrid combination of tracks and wheels. Tracked and wheeled locomotion modes are independent from one another, and are cascaded along two orthogonal axes to provide multi-directional mobility. An actuated mechanism toggles between these two modes for optimal mobility under different surface-traction conditions, and further adds an additional translational axis of mobility. That is, the robot can move in the longitudinal direction via the tracks on rugged terrain for high traction, in the lateral direction via the wheels on smooth terrain for high-speed locomotion, and along the vertical axis via the translational joint. Additionally, the robot is capable of yaw axis mobility using differential drives in both tracked and wheeled modes of operation. The paper presents design and analysis of the proposed robot along with a dynamic stabilization algorithm to prevent the robot from tipping over while carrying an external payload on inclined surfaces. Experimental results using an integrated prototype demonstrate multi-directional capabilities of the mobile platform and the dynamic stability algorithm to stabilize the robot while carrying various external payloads on inclined surfaces measuring up to 2.5 kg and 10 deg, respectively.

Leg Trajectory Planning for Quadruped Robots with High-Speed Trot Gait

In this paper, a single leg platform for quadruped robots is designed based on the motivation of high-speed locomotion. The leg is designed for lightweight and low inertia with a structure of three joints by imitating quadruped animals. Because high acceleration and extensive loadings will be involved on the legs during the high-speed locomotion, the trade-off between the leg mass and strength is specifically designed and evaluated with the finite element analysis. Moreover, quadruped animals usually increase stride frequency and decrease contact time as the locomotion speed increases, while maintaining the swing duration during trot gait. Inspired by this phenomenon, the foot-end trajectory for quadruped robots with a high-speed trot gait is proposed. The gait trajectory is planned for swing and stance phase; thus the robot can keep its stability with adjustable trajectories while following a specific gait pattern. Especially for the swing phase, the proposed trajectory can minimize the maximum acceleration of legs and ensure the continuity of position, speed, and acceleration. Then, based on the kinematics analysis, the proposed trajectory is compared with the trajectory of Bézier curve for the power consumption. Finally, a simulation with Webots software is carried out for verifying the motion stability with two trajectory planning schemes respectively. Moreover, a motion capture device is used for evaluating the tracking accuracy of two schemes for obtaining an optimal gait trajectory suitable for high-speed trot gait.

High-speed Crawling-like Locomotion Robot and Its Application to Paper-feeding Manipulation System

High-speed Crawling-like Locomotion Robot and Its Application to Paper-feeding Manipulation System

Functional morphology of endurance swimming performance and gait transition strategies in balistoid fishes.

Triggerfishes and filefishes (Balistoidea) use balistiform locomotion to power steady swimming with their dorsal and anal fins, and transition to a gait dominated by body and caudal fin (BCF) kinematics at high speeds. Fin and body shapes are predicted to be strong determinants of swimming performance and gait transitions. The goal of this study was to combine morphometrics and critical swimming tests to explore the relationships between fin and body shapes and swimming performance in a phylogenetic context in order to understand the evolution of balistiform swimming. Among 13 species of balistoid fishes, those with high aspect ratio fins tended to achieve higher critical swimming speeds than fishes with low aspect ratio fins. Species with long, large median fins and wide caudal peduncles used the balistiform gait alone for a larger percentage of their total critical swimming speed than fishes with short, small median fins and narrow caudal peduncles. Although analyses revealed overall positive relationships between median fin aspect ratios and gait transition speeds, fishes on both ends of the aspect ratio spectrum achieved higher swimming speeds using the balistiform gait alone than fishes with median fins of intermediate aspect ratios. Each species is specialized for taking advantage of one gait, with balistiform specialists possessing long, large median fins capable of the large power requirements of high-speed swimming using the median fins alone, while BCF specialists possess short, small median fins, ill-suited for powering high-speed balistiform locomotion, but narrow caudal peduncles capable of efficient caudal fin oscillations to power high-speed locomotion.

Inverted and vertical climbing of a quadrupedal microrobot using electroadhesion.

The ability to climb greatly increases the reachable workspace of terrestrial robots, improving their utility for inspection and exploration tasks. This is particularly desirable for small (millimeter-scale) legged robots operating in confined environments. This paper presents a 1.48-gram and 4.5-centimeter-long tethered quadrupedal microrobot, the Harvard Ambulatory MicroRobot with Electroadhesion (HAMR-E). The design of HAMR-E enables precise leg motions and voltage-controlled electroadhesion for repeatable and reliable climbing of inverted and vertical surfaces. The innovations that enable this behavior are an integrated leg structure with electroadhesive pads and passive alignment ankles and a parametric tripedal crawling gait. At a relatively low adhesion voltage of 250 volts, HAMR-E achieves speeds up to 1.2 (4.6) millimeters per second and can ambulate for a maximum of 215 (162) steps during vertical (inverted) locomotion. Furthermore, HAMR-E still retains the ability for high-speed locomotion at 140 millimeters per second on horizontal surfaces. As a demonstration of its potential for industrial applications, such as in situ inspection of high-value assets, we show that HAMR-E is capable of achieving open-loop, inverted locomotion inside a curved portion of a commercial jet engine.

ON THE IMPACT OF THE CHARACTERISTICS OF ROLLING STOCK ON SHUNTING RESISTANCE OF RAIL CIRCUITS

For the English full text of the article please see the attached PDF-File (English version follows Russian version).ABSTRACT The effect of a combination of rolling stock characteristics, including wheel set electrical resistance, axle/wheel load, vehicle speed, electrical resistance of «wheel-rail» contact, has been studied. The data of three reference vehicles - a biaxial rail car, a four-axle conventional and a four-axle high-speed locomotive were studied. Two approaches are used which are deterministic and probabilistic ones (Monte Carlo method). On their basis, the process of detecting static and dynamic shunts for three ranges of speeds of movement and two degrees of rail pollution with an insulating film is provided. Keywords: railway, rail circuit, track circuit, electrical resistance, static shunt, dynamic shunt, rolling stock.