Walking Locomotion Research Articles

Assessing the quality of steady-state visual-evoked potentials for moving humans using a mobile electroencephalogram headset.

Recent advances in mobile electroencephalogram (EEG) systems, featuring non-prep dry electrodes and wireless telemetry, have enabled and promoted the applications of mobile brain-computer interfaces (BCIs) in our daily life. Since the brain may behave differently while people are actively situated in ecologically-valid environments versus highly-controlled laboratory environments, it remains unclear how well the current laboratory-oriented BCI demonstrations can be translated into operational BCIs for users with naturalistic movements. Understanding inherent links between natural human behaviors and brain activities is the key to ensuring the applicability and stability of mobile BCIs. This study aims to assess the quality of steady-state visual-evoked potentials (SSVEPs), which is one of promising channels for functioning BCI systems, recorded using a mobile EEG system under challenging recording conditions, e.g., walking. To systematically explore the effects of walking locomotion on the SSVEPs, this study instructed subjects to stand or walk on a treadmill running at speeds of 1, 2, and 3 mile (s) per hour (MPH) while concurrently perceiving visual flickers (11 and 12 Hz). Empirical results of this study showed that the SSVEP amplitude tended to deteriorate when subjects switched from standing to walking. Such SSVEP suppression could be attributed to the walking locomotion, leading to distinctly deteriorated SSVEP detectability from standing (84.87 ± 13.55%) to walking (1 MPH: 83.03 ± 13.24%, 2 MPH: 79.47 ± 13.53%, and 3 MPH: 75.26 ± 17.89%). These findings not only demonstrated the applicability and limitations of SSVEPs recorded from freely behaving humans in realistic environments, but also provide useful methods and techniques for boosting the translation of the BCI technology from laboratory demonstrations to practical applications.

Reconsidering locomotor habits and life style of the Balearic insular giant rodent Hypnomys Bate, 1918 from the allometry of the limb long bones

The genus Hypnomys Bate, 1918 includes some endemic Neogene chronospecies from Mallorca and Menorca, evolved in insularity conditions from the Lower Pliocene to the human arrival at the archipelago. The study of the allometric proportions (functional length and sagittal diameter) of the limbs’ long bones of Hypnomys eliomyoides Agusti, 1980 (Lower Pleistocene of Menorca), Hypnomys sp. (Pleistocene of Menorca), Hypnomys onicensis (Reumer, 1994) (Upper Pliocene-Lower Pleistocene of Mallorca) and Hypnomys morpheus Bate, 1918 (Upper Pleistocene of Mallorca) only indicates small differences with the garden dormouse (Eliomys quercinus Linnaeus, 1776) and other mainland rodents and insectivores. The study about the locomotion type by means of Similarity Matrix of Bou indicates that 1) Hypnomys spp. presents the greater similarities with the arboreal, jumping and gliding species; 2) the jumping and digging life style of Hypnomys spp. are more developed (25%) than in E. quercinus; 3) the walking locomotion of Hypnomys spp. is only a 7% greater than in E. quercinus; and 4) the degree of similarity with the gliding locomotion of Hypnomys sp. is greater (17%) than in E. quercinus. Some of this data indicates that Hypnomys spp. was better adapted to the arboreal life than E. quercinus, due to the relationship between the jumping and gliding capacities with the arboreal locomotion. The greater similarity of Hypnomys spp. with the walking locomotion does not necessarily involve more terrestrial habits. Our interpretation contrasts with earlier conclusions of Hypnomys life style (Hypnomys cf. onicensis and Hypnomys morpheus) where the terrestrial locomotion was overestimated in front of the arboreal locomotion. The locomotion type of Hypnomys would be related with the presence of important forest masses on the Balearic Islands during the Neogene, a different degree of environmental stress from that of the mainland ecosystems and a probable expansion of the ecological niche occupied by these species.

Development of quadruped walking locomotion gait generator using a hybrid method

The earth, in many areas is hardly reachable by the wheeled or tracked locomotion system. Thus, walking locomotion system is becoming a favourite option for mobile robot these days. This is because of the ability of walking locomotion to move on the rugged and unlevel terrains. However, to develop a walking locomotion gait for a robot is not a simple task. Central Pattern Generator (CPGs) method is a biological inspired method that is introduced as a method to develop the gait for the walking robot recently to tackle the issue faced by the conventional method of pre-designed trajectory based method. However, research shows that even the CPG method do have some limitations. Thus, in this paper, a hybrid method that combines CPG and the pre-designed trajectory based method is introduced to develop a walking gait for quadruped walking robot. The 3-D foot trajectories and the joint angle trajectories developed using the proposed method are compared with the data obtained via the conventional method of pre-designed trajectory to confirm the performance.

Ethological studies of the Veined Octopus Amphioctopus marginatus (Taki) (Cephalopoda: Octopodidae) in captivity, Kerala, India

Five Veined Octopus Amphioctopus marginatus (Taki), collected from Vizhinjam Bay in the Thiruvananthapuram District of Kerala, India were kept in aquariums to study their behaviour in captivity. Primary and secondary defence mechanisms studied included crypsis, hiding and escape behaviour. Deimatic behaviour was used by captive animals when camouflage failed and they were threatened. Crawling behaviour to escape from the aquarium was observed in all specimens. Stilt walking and bi-pedal locomotion were also observed. As a defence behaviour, A. marginatus used aquarium rocks to protect the soft underside of their bodies. A. marginatus demonstrated tool use of coconut shells to make protective shelters, carrying the shells for future use. A female specimen also selected a coconut shell for egg laying and performed parental care by continuously cleaning and aerating her eggs with her arms and by squirting jets of water over the eggs.

1P1-M05 三次元物理空間における恐竜の歩行行動の獲得(進化・学習とロボティクス(2))

Many studies have been done on autonomous locomotion robots based on physics modeling. However, most of them concern on walking and swimming locomotion and there are few studies on a series of walking locomotion for a big living thing. In this study, we focus on a series of walking locomotion using dinosaur model (T-Rex). We applied ANN, GA and CPG to acquire the walking behavior based on physics modeling and verified that a suitable behavior can be acquired through numerical experiments.

S5-3: Dynamic Invariants in Walking through an Aperture While Holding a Tray with Two Hands

Gibson's (1979 The Ecological Approach to Visual Perception) ecological approach to visual perception is based on several key notions (i.e., affordance, optic flow, and invariants). Early research focused on identifying invariants (π-numbers) to describe affordances using geometric body-scaled measures. Kadar and Koszeghy (2010 International Journal of Sport Psychology 41(3) 80–81) generalized π-numbers to invariant functions (π-functions) to allow dynamically scaled description of driving through gates of variable width. The present study further investigated the dynamic invariants of human locomotion in walking towards and passing through gates. Six participants were instructed to walk through gates of four different sizes with either comfortable or fast walking speed while holding a tray by two hands. Consistent with the results of Kadar and Koszeghy (2010) dynamically-scaled π-functions were identified. The speed control of the approach phase was further assessed in relation to the use of the optical τ parameter derived from optic flow specifying estimated time to contact with the virtual plane defined by the frontal surfaces of the aperture. Aperture size and walking speed have influenced the control of speed at the approach phase: the derivative of τ in the neighborhood of the aperture increased with increasing width of the aperture. Analysis of the approach phase suggests a need for searching an even higher-level invariant structure of the dynamics of this passing through task.

Limited transfer of newly acquired movement patterns across walking and running in humans.

The two major modes of locomotion in humans, walking and running, may be regarded as a function of different speed (walking as slower and running as faster). Recent results using motor learning tasks in humans, as well as more direct evidence from animal models, advocate for independence in the neural control mechanisms underlying different locomotion tasks. In the current study, we investigated the possible independence of the neural mechanisms underlying human walking and running. Subjects were tested on a split-belt treadmill and adapted to walking or running on an asymmetrically driven treadmill surface. Despite the acquisition of asymmetrical movement patterns in the respective modes, the emergence of asymmetrical movement patterns in the subsequent trials was evident only within the same modes (walking after learning to walk and running after learning to run) and only partial in the opposite modes (walking after learning to run and running after learning to walk) (thus transferred only limitedly across the modes). Further, the storage of the acquired movement pattern in each mode was maintained independently of the opposite mode. Combined, these results provide indirect evidence for independence in the neural control mechanisms underlying the two locomotive modes.

Approximating the relationship among the degree of the reaction forces and the nodes on footprint during a stance phase

This study examined the foot biomechanics that are utilized when foot is in contact with the ground during a stance phase. The purpose of the study was to investigate the normalized ground reaction forces that impacted certain sections and points on the footprint, and to identify patterns in the degrees to which these forces occurred. Foot was modeled in such a manner that a vertex represented a bone and an edge represented a joint, and a graph that depicted the foot was created. Twelve nodes were marked on the footprint and these were linked together to create a gait path. By fusing the graph and the gait path and by manipulating the mathematical models, a profile for an ideal bipedal walking locomotion was developed. A male subject performed bipedal walking through a force plate system in order to obtain the profile that reflected actual bipedal walking. The actual and the proposed profiles were compared and there were significant similarities between the two profiles, with both exhibiting an double-bump pattern. It is therefore viable that the approximation techniques proposed in this work may provide an alternative means over the application of a force plate system to generate a profile for bipedal walking. However, the accuracy and reliability of the results yielded from this technique need further investigation.

Experimental Determination of Horizontal Motion of Human Center of Gravity During Squatting

The excursion of the center of gravity (COG) line is often examined in terms of balance control, standing, walking or running locomotion, etc. Although these examinations are carried out on multiple human subjects, the obtained results are not bound to any “human-like” quantity such as the anatomically well-defined and widely accepted angle of flexion. This paper is meant to prove the following hypotheses: the horizontal excursion of the COG line changes its position during squatting in contrary with steady-state assumption and it can be derived as a single empirical function of flexion angle. A test setup was developed for the experiments, alongside with an experiment protocol and a special construction method to obtain the results. During the experiments, 16 healthy, male and female participants’ data were used as a basis for the dimensionless λfunctions. The results showed common characteristics between the subjects’ data, and suggested that the general relationship between the squatting and the excursion of COG can be described with linear, dimensionless functions. As a final goal of this study, the obtained dimensionless functions will be used in a mathematical model, which is being developed.

1A1-P04 物理モデリングによる犬モデルの自律行動 : 起き上がり動作と姿勢の安定化(進化・学習とロボティクス)

Many studies have been done on autonomous locomotion robots based on physics modeling. However, most of them concern on walking and swimming locomotion and there are few studies on a series of walking locomotion. In this study, we focus on a dog walking locomotion and on dog's standing up behavior, which is a starting behavior of walking. We applied GA and ANN to acquire the standing up behavior based on physics modeling and verified that a suitable behavior can be acquired through numerical experiments.

Accurate tracking of legged robots on natural terrain

Statically stable walking locomotion research has focused mainly on robot design and gait generation. However, there is a need to expand robots' capabilities so that walking machines can accomplish the kinds of real tasks for which they are eminently suited. Many such tasks demand trajectory tracking, but researchers have traditionally ignored this subject. This article focuses on the tracking of predefined trajectories with hexapod robots walking on natural terrain with forbidden zones. The method presented herein, which relies on gait algorithms defined elsewhere, describes certain localization strategies and control techniques that have been employed to follow trajectories accurately and have been implemented in a real walking hexapod. Several experimental examples are included to assess the proposed algorithms.

Comparison of pelvic complex kinematics during normal locomotion in treadmill vs. overground walking

Deviations from the normal movement pattern relates pathological gait. Conditions such as leg length inequality, increased lumbar lordosis and trunk bending relates to the abnormal kinematics of the pelvis. The assessment and rehabilitation of human locomotion is frequently assisted by a treadmill to simulate overground walking. Previous research suggest differences in temporal and angular kinematics when comparing treadmill to overground, questioning whether the treadmill replicates a similar setting as overground walking [1]. Similarly, treadmill running was commonly associated with increased anterior tilt when compared to overground. Furthermore, the investigations into the comparison of treadmill and overground running have produced conflicting results. Reported differences have been attributed to variations in surface, familiarisation, marker placement and identification protocol for toe off and heel strike [2, 3]. While, examining the effects of a lumbar corset on pelvic kinematics using a treadmill, a previous study indicated significant differences in rotations. However, no differences were reported in the sagittal and transverse planes [4]. Another investigation analysed the temporal differences of overground and treadmill walking and found at identical speeds, the stance period shortened by 6.7%, with increased cadence by 6.6% on the treadmill [5]. Similarly, Alton et al. [1] reported treadmill walking produced increases in cadence and decreases in stance time. Although, the treadmill has been described as advantageous in other comparative studies because of its convenience and the ease of control, the results reported in a previous study identified smaller ranges in the frontal and transverse anatomical plane for the pelvis whilst walking on the treadmill compared to overground. [4]. Furthermore, there are changes in variability and local stability for treadmill walking. In this context, another investigation concludes that treadmills may produce deceptive results [6]. When comparing overground and treadmill ambulation, the current study attempted to determine whether there are any reported or further differences in spatio temporal parameters of the pelvic complex and if these are related to gender differences.

Walking Locomotion System for Quadruped Mobile Platform with Adaptive Hoofs

The mobile platforms are used to perform programmed or remote controlled movement in a very large working space. In the terrestrial locomotion two systems are used: based on rolling (wheeled and tracked), or based on walking. This paper presents a walking locomotion system with four legs, some identical jointed kinematics chains, where every kinematics pair is actuated. The legs have the platform as the base element; the other end of the leg is jointed with an adaptive hoof. The hoofs are actuated by synchronous transmission. Together, the legs and the hoofs, define a quadruped walking locomotion system.

Hybrid control of biped robots in the double-support phase via H∞ approach and fuzzy neural networks

A quadratic stabilisation fuzzy neural network hybrid control scheme is proposed for biped robots in the double-support phase. First, the authors considered the holonomic constraints. The walking locomotion of biped robots in the double-support phase is modelled as a reduced order position/force hybrid model, which integrates the position/force hybrid model with the reduced-order model. Then a new fuzzy neural network hybrid control scheme is presented, in which H∞ approach, inverse system method and variable structure control are used to attenuate the effect of external disturbances and parametric uncertainties. Simulation results are reported in order to show the performance of the proposed control scheme.

Optimal Biped Walking Locomotion Solved by Trajectory Planning Method

This paper describes an optimal trajectory planning of walking locomotion for a planar biped walking mechanism which has thighs, shanks and small feet. The biped mechanism was modeled to be a 3-degree-of-freedom (dof) link system composed of a stance leg and a 2-dof swing leg. The one step walking locomotion is divided into two phases, i.e., the swing motion of 2-dof swing until knee collision and the swing motion of the straight leg until toe collision. It is assumed that the knee collision of the swing leg and the toe collision at the foot exchange are plastic and occur instantly. The motion of the swing and stance legs in the first phase is solved by the optimal trajectory planning based on the function approximation method. Under the full-actuated condition at the hip, knee and ankle joints, we obtained the optimal trajectory solution with a minimum square integral of input torque. We also obtained a sub-optimal walking locomotion for an under-actuated system whose ankle is a passive joint. The validity of the optimal trajectory solution is confirmed by a forward dynamic simulation. The optimal trajectory solution for the human body parameter values exhibits a natural and stable walking locomotion with the step length of 0.33 m and a step period of 0.62 s.

Walking in skates (Chondrichthyes, Rajidae): anatomy, behaviour and analogies to tetrapod locomotion

Pelvic fin walking in skates is common. However, the structure and function of pelvic fins have not been analysed. Pelvic fins of skates of the genus Psammobatis and Rioraja agassizi are externally divided into an anterior leg-like lobe and a posterior fin-like lobe. Internally, the anterior lobes are supported by a compound radial, a proximal radial and distal radials that resemble a thigh, a calf and a foot, respectively, and three associated radials arising from the pelvic girdle. A highly developed radial condyle on the pelvic girdle enables broad ‘limb’ movements. The muscular arrangement of the anterior lobes is formed by protractor, retractor, flexor and extensor muscles, clearly departing from the generalized fin muscle arrangement of elasmobranchs. Walking is composed of propulsion and recovery phases. A backward movement of the compound radial in the horizontal plane characterizes the propulsive phase. The proximal radial connects vertically the compound radial with the foot-like distal radials, which are anchored on the bottom. During the recovery phase, the foot-like structure is lifted off the bottom and the entire limb-like anterior lobe is moved forwards for starting a new cycle. Walking in skates resembles the ancestral tetrapod sprawling locomotion seen in many salamanders and lizards. Pelvic fin anatomy and walking behaviour in skates and hemiscylliid sharks are compared. Ecological and evolutionary implications of walking locomotion in skates are also discussed. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 77 , 35‐41. ADDITIONAL KEYWORDS: Elasmobranchii ‐ biomechanics ‐ vertebrate limbs ‐ morphology ‐ mosaic evolution.

A Multi-Modal and Collaborative Human–Machine Interface for a Walking Robot

Walking locomotion has been proved as an adequate technique for autonomous motion on an uneven terrain. However, natural scenarios can be extremely complex and human intervention is regularly required. In such a case, a dialogue system known as human–machine interface (HMI) is essential for interrelation between human and machine. The objective of this paper is to present a human–machine interface developed for a four-legged robot. This HMI is based on a multi-modal interface, which integrates some ideas about collaborative control. It was developed as an operator's interface for guiding a walking robot, but it can also be used as a tool for analysing and debugging new gait algorithms. The interface includes some methods for defining robot trajectory and graphic representations for gaining information on both the robot and its environment. This work is tailored to the SILO4 walking robot; therefore, the SILO4 mechanism and control system are first introduced to lay out the possibilities of this new walking robot. Then, the main concepts, on which the HMI design is based, are introduced prior to the description of the different modules and functionality of the human–machine interface. Finally, some simulations and experiments with the SILO4 walking robot have been conducted to validate the performance of the HMI, presented in this article.

An Optimal Walking Trajectory of Biped Mechanism. 1st Report. Optimal Trajectory Planning Mothod and Gait Solutions Under Full-Actuated Condition.

This paper describes an optimal trajectory planning of walking locomotion for a biped mechanism which has thighs, shanks and small feet. We model the mechanism to be a 3-DOF link system composed of a stance leg and a 2-DOF swing leg. The one step walking locomotion is divided into two phases, i, e., the swing motion of 2-DOF swing leg with stance leg, and the free motion of straight swing leg with stance leg. It is assumed that the knee collision of the swing leg and the toe collision at foot exchage are plastic and occur instantly. The motion of the swing and stance legs in the first phase is solved by the optimal trajectory planning method based on the function approximation method. Under the full-actuated condition at the hip, knee and ankle joints, we obtained the minimum square input trajectory solutions with natural gaits for biped mechanism parameter values and adult's parameter values. One step period of the optimal solution for the human parameter values is 0.62s which is close to that of human. The validity of the optimal trajectory planning method is confirmed by forward dynamic simulation.

Walking machines - initial testbeds, first industrial applications and new research

Walking locomotion theory has been drastically improved during the last decade and now the technology seems to be ready for industrial applications. More than 60 different climbing and walking machines developed in research laboratories and universities have been catalogued, but industrial applications are emerging very slowly. This article covers some of the activity and production run at the Institute for Industrial Automation (CSIC) related to development of prototypes for both research purposes and industrial applications as well.

Configuration of Autonomous Walkers for Extreme Terrain

Robots that can competently, efficiently, and autonomously operate in extreme terrain do not exist. Although walking locomotion offers unique advantages, existing walking mech anisms are not suited to the comprehensive requirements of extreme terrain autonomy. This work synthesizes and ana lyzes candidate walker configurations, implements and tests a walker of unprecedented capability and design, and devel ops insights regarding walker configuration and the class of orthogonal-legged walking robots. Three orthogonal-legged walker configurations are described and compared in a variety of terrain situations. Two of the configurations-circulating and weaving-are unique, as they place recovering feet ahead of supporting feet and are specifically notable for their long stride. The third uses a traditional follow-the-leader gait. The Ambler is a fully operable autonomous walking robot built in part to further investigate the benefits of the orthogonal leg and circulating gait configuration. The orthogonal leg appears to be well suited to autonomous walking in extreme terrain. A circulating walker's advantages—as demonstrated by the Am bler-notwithstanding, a follow-the-leader orthogonal-legged walker appears to have superior overall mobility and stability (the crucial capabilities in extreme terrain).