When is Vestibular Information Important During Walking?

Locomotion relies on vision, somatosensory input, and vestibular information. Both vision and somatosensory signals have been shown to be phase dependently modulated during locomotion; however, the regulation of vestibular information has not been investigated in humans. By delivering galvanic vestibular stimulation (GVS) to subjects at either heel contact, mid-stance, or toe-off, it was possible to investigate when vestibular information was important during the gait cycle. The results indicated a difference in the vestibular regulation of upper versus lower body control. Upper body responses to GVS applied at different times did not differ in magnitude for the head ( P = 0.2383), trunk ( P = 0.1473), or pelvis ( P = 0.1732) showing a similar dependence on vestibular information for upper body alignment across the gait cycle. In contrast, foot placement was dependent on the time when stimulation was delivered. Changes in foot placement were significantly larger at heel contact (during the double support phase) than when stimulation was delivered at mid-stance (in the single support phase of the gait cycle; P = 0.0193). These latter results demonstrate, for the first time, evidence of phase-dependent modulation of vestibular information during human walking.

Download Full-text

The Effect of the Toe on the Biped Robot

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.325-326.1076 ◽

2013 ◽

Vol 325-326 ◽

pp. 1076-1082

Author(s):

Seyed Mehdi Torklarki ◽

Mohammad Danesh

Keyword(s):

Reaction Force ◽

Stability Margin ◽

Biped Robot ◽

Body Motion ◽

Upper Body ◽

Biped Robots ◽

Double Support ◽

The Stability ◽

Single Support Phase ◽

Support Phase

Evaluation of 9-DOF biped robots based on designated smooth and stable trajectories with two added toes is a challenging problem that is the focus of this paper. Simultaneously rotation of feet and toes is considered, which allows the robot to walk more efficiently and like a human being. A desired trajectory for the lower body is designed to increase the stability margin. This obtained by fitting proper polynomials at appropriate break points. Then, the upper body motion is planned based on the Zero Moment Point (ZMP) criterion to provide a stable motion for the biped robot. Next, dynamics equations are obtained for both single support phase (SSP) and double support phase (DSP). On the other hand, two biped robots, which one accompanied by toes, are also compared. Simulation results reveal that the biped robots with toes have better stability margin, less power consumption and more vertical reaction force.

Download Full-text

Effect of Heel to Toe Walking on Time Optimal Walking of a Biped During Single Support Phase

Volume 3: Biomedical and Biotechnology Engineering ◽

10.1115/imece2014-38214 ◽

2014 ◽

Cited By ~ 1

Author(s):

Tara Farizeh ◽

Mohammad Jafar Sadigh

Keyword(s):

Whole Body ◽

Maximum Speed ◽

Flat Foot ◽

Double Support ◽

Time Optimal ◽

Foot Model ◽

Two Phases ◽

Single Support Phase ◽

Toe Walking ◽

Support Phase

Dynamic modeling of a biped has gained lots of attention during past few decades. While stability and energy consumption were among the first issues which were considered by researchers, nowadays achieving maximum speed and improving pattern of motion to reach that speed are the important targets in this field. Walking model of bipeds usually includes two phases, single support phase (SSP), in which only the stance foot is in contact with the ground while the opposite leg is swinging; and double support phase (DSP) in which the swing leg is in contact with the ground in addition to the rear foot. It is common in the simplified model of walking to assume the stance leg foot, flat during the entire SSP; but one may know that for human walking, there is also a sub-phase during SSP in which the heel of stance foot leaves the ground while the whole body is supported by toe link. Actually in this sub phase the stance leg foot rotates around the toe joint. This paper is trying to study the effect of toe-link and heel to toe walking model on dynamic and specially speed of walking compare to flat foot model.

Download Full-text

Walking Gait of a Biped with a Wearable Walking Assist Device

International Journal of Humanoid Robotics ◽

10.1142/s0219843615500188 ◽

2015 ◽

Vol 12 (04) ◽

pp. 1550018 ◽

Cited By ~ 6

Author(s):

Yannick Aoustin

Keyword(s):

Dynamic Model ◽

Unique Solution ◽

Energy Cost ◽

Assist Device ◽

Double Support ◽

Kinematic Chains ◽

Walking Gait ◽

Time Period ◽

Single Support Phase ◽

Support Phase

A ballistic walking gait is designed for a planar biped equipped with a wearable walking assist device. The biped is a seven-link planar biped with two legs, two feet, and a trunk. The wearable walking assist device is composed of a bodyweight support, two upper legs, two lower legs, and two shoes. The dynamic model of the biped with its walking assist device, containing two closed kinematic chains, is calculated by virtually cutting each of both loops at one of their point. In the single support phase, the biped with its assist device moves due to the existence of a momentum, produced mechanically, without applying active torques in the inter-link joints. The biped and this assist device are controlled with impulsive torques at the instantaneous double support to obtain a cyclic gait. The impulsive torques are applied in the six inter-link joints of the biped and in several inter-link joints of the wearable walking assist device. The following distributions of impulsive torques, in the knees or the ankles, hips and knees, hips and ankles, or knees and ankles and the fully assist device, are compared with the case of no assistance for the biped. Each time, an infinity of solutions exists to find the impulsive torques. An energy cost functional defined from these impulsive torques is minimized to determine a unique solution. Numerical results show that for a given time period and a given length of the walking gait step, the assistance of the hips is a good compromise to help the biped.

Download Full-text

Dysfunctional muscle activities and co-contraction in the lower-limb of lumbar disc herniation patients during walking

Scientific Reports ◽

10.1038/s41598-020-77150-7 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Wei Wang ◽

Hui Wei ◽

Runxiu Shi ◽

Leitong Lin ◽

Lechi Zhang ◽

...

Keyword(s):

Lumbar Disc Herniation ◽

Disc Herniation ◽

Lower Limb ◽

Gait Cycle ◽

Lumbar Disc ◽

Lower Limbs ◽

Heel Strike ◽

Control Group ◽

Double Support ◽

Support Phase

AbstractThis study aimed to investigate lower-limb muscle activities in gait phases and co-contraction of one gait cycle in patients with lumbar disc herniation (LDH). This study enrolled 17 LDH patients and 17 sex- and age-matched healthy individuals. Bilateral muscle activities of the rectus femoris (RF), biceps femoris long head (BL), tibialis anterior (TA), and lateral gastrocnemius (LG) during walking were recorded. The gait cycle was divided into four phases by the heel strike and top off according to the kinematics tracks. Root mean square (RMS), mean frequency (MF), and co-contraction of surface electromyography signals were calculated. The LDH patients showed enhanced BL RMS during the single support phase (SS), second double support phase, and swing phase (SW) as well as decreased MF of RF during SS and of TA and LG during SW (p < 0.05). The co-contraction of the TA-LG was increased in LDH patients than in the control group (p < 0.05). Positive correlations were observed between TA-LG co-contraction (affected side, r = 0.557, p = 0.020; contralateral side, r = 0.627, p = 0.007) and the Oswestry disability index scores in LDH patients. LDH patients have increased BL firing rate and insufficient motor unit recruitment in specific phases in the lower limbs during walking. Dysfunction in LDH patients was associated with immoderate intermuscular co-contraction of the TA-LG during walking.

Download Full-text

A force-resisting balance control strategy for a walking biped robot under an unknown, continuous force

Robotica ◽

10.1017/s0263574714002616 ◽

2014 ◽

Vol 34 (7) ◽

pp. 1495-1516

Author(s):

Yeoun-Jae Kim ◽

Joon-Yong Lee ◽

Ju-Jang Lee

Keyword(s):

External Force ◽

Control Strategy ◽

Balance Control ◽

Biped Robot ◽

Second Step ◽

Double Support ◽

Zero Moment ◽

External Forces ◽

Single Support Phase ◽

Support Phase

SUMMARYIn this paper, we propose and examine a force-resisting balance control strategy for a walking biped robot under the application of a sudden unknown, continuous force. We assume that the external force is acting on the pelvis of a walking biped robot and that the external force in the z-direction is negligible compared to the external forces in the x- and y-directions. The main control strategy involves moving the zero moment point (ZMP) of the walking robot to the center of the robot's sole resisting the externally applied force. This strategy is divided into three steps. The first step is to detect an abnormal situation in which an unknown continuous force is applied by examining the position of the ZMP. The second step is to move the ZMP of the robot to the center of the sole resisting the external force. The third step is to have the biped robot convert from single support phase (SSP) to double support phase (DSP) for an increased force-resisting capability. Computer simulations and experiments of the proposed methods are performed to benchmark the suggested control strategy.

Download Full-text

Walking cadence affects the recruitment of the medial-lateral balance mechanisms

10.1101/658070 ◽

2019 ◽

Cited By ~ 2

Author(s):

Tyler Fettrow ◽

Hendrik Reimann ◽

David Grenet ◽

Jeremy Crenshaw ◽

Jill Higginson ◽

...

Keyword(s):

Older Adults ◽

Virtual Reality ◽

Neural Control ◽

Gait Cycle ◽

Balance Control ◽

Vestibular Stimulation ◽

Lateral Ankle ◽

Foot Placement ◽

Ankle Inversion ◽

Gait Characteristics

AbstractWe have previously identified three balance mechanisms that young healthy adults use to maintain balance while walking. The three mechanisms are: 1) The lateral ankle mechanism, an active modulation of ankle inversion/eversion in stance; 2) The foot placement mechanism, an active shift of the swing foot placement; and 3) The push-off mechanism, an active modulation of the ankle plantarflexion angle during double stance. Here we seek to determine whether there are changes in neural control of balance when walking at different cadences and speeds. Twenty-one healthy young adults walked on a self-paced treadmill while immersed in a 3D virtual reality cave, and periodically received balance perturbations (bipolar galvanic vestibular stimulation) eliciting a perceived fall to the side. Subjects were instructed to match two cadences specified by a metronome, 110bpm (High) and 80bpm (Low), which led to faster and slower gait speeds, respectively. The results indicate that subjects altered the use of the balance mechanisms at different cadences. The lateral ankle mechanism was used more in the Low condition, while the foot placement mechanism was used more in the High condition. There was no difference in the use of the push-off mechanism between cadence conditions. These results suggest that neural control of balance is altered when gait characteristics such as cadence change, suggesting a flexible balance response that is sensitive to the constraints of the gait cycle. We speculate that the use of the balance mechanisms may be a factor resulting in well-known characteristics of gait in populations with compromised balance control, such as slower gait speed in older adults or higher cadence in people with Parkinson’s disease.

Download Full-text

Implementation and Integration of Fuzzy Algorithms for Descending Stair of KMEI Humanoid Robot

EMITTER International Journal of Engineering Technology ◽

10.24003/emitter.v8i2.535 ◽

2020 ◽

pp. 372-388

Author(s):

Wulandari Puspita Sari ◽

R. Sanggar Dewanto ◽

Dadet Pramadihanto

Keyword(s):

Humanoid Robot ◽

Fuzzy Logic Controller ◽

Integrated Control ◽

Step Length ◽

Smooth Transition ◽

Double Support ◽

Walking Gait ◽

Single Support Phase ◽

Support Phase ◽

Double Support Phase

Locomotion of humanoid robot depends on the mechanical characteristic of the robot. Walking on descending stairs with integrated control systems for the humanoid robot is proposed. The analysis of trajectory for descending stairs is calculated by the constrains of step length stair using fuzzy algorithm. The established humanoid robot on dynamically balance on this matter of zero moment point has been pretended to be consisting of single support phase and double support phase. Walking transition from single support phase to double support phase is needed for a smooth transition cycle. To accomplish the problem, integrated motion and controller are divided into two conditions: motion working on offline planning and controller working online walking gait generation. To solve the defect during locomotion of the humanoid robot, it is directly controlled by the fuzzy logic controller. This paper verified the simulation and the experiment for descending stair of KMEI humanoid robot.

Download Full-text

Angular momentum regulation may dictate the slip severity in young adults

10.1101/785808 ◽

2019 ◽

Author(s):

Mohammad Moein Nazifi ◽

Kurt Beschorner ◽

Pilwon Hur

Keyword(s):

Young Adults ◽

Angular Momentum ◽

Center Of Mass ◽

Upper Body ◽

Group Differences ◽

Normal Gait ◽

Double Phase ◽

Single Support Phase ◽

Time Lead ◽

Support Phase

AbstractFalls vastly affect the economy and the society with their high cost, injuries, and mortalities. Slipping is the main trigger for falling. Yet, individuals differ in their ability to recover from slips. Mild slippers can accommodate slips without falling, whereas severe slippers indicate inadequate or slow pre-or post-slip control that make them more prone to fall after a slip. Knowing the discrepancies in different kinematic and kinetic variables in mild and severe slippers helps pinpoint the adverse control responsible for severe slipping and falling. This study examined Center of Mass (COM) height, sagittal angular momentum (H), upper body kinematics, and the duration of single/double phase in mild and severe slippers for both normal walking and slipping to identify their differences and possible relationships. Possible causality of such relationships were also studied by observing the time-lead of the deviations. Twenty healthy young adults walked in a long walkway for several trials and were slipped unexpectedly. They were classified into mild and severe slippers based on their slip severity. No inter-group differences were observed in the upper extremity kinematics. It was found that mild and severe slippers do not differ in the studied variables during normal gait; however, they do show significant differences through slipping. Compared to mild slippers, sever slippers lowered their COM height following a slip, presented higher H, and shortened their single support phase (p-value<0.05 for all). Based on the time-lead observed in H over all other variables suggests that angular momentum may be the key variable in controlling slips.

Download Full-text

The Effect of a Virtual No-Step Zone on Balance Control in Walking

10.1101/2020.02.28.970152 ◽

2020 ◽

Cited By ~ 1

Author(s):

Tyler Fettrow ◽

Stephen DiBianca ◽

Fernando Vanderlinde dos Santos ◽

Hendrik Reimann ◽

John Jeka

Keyword(s):

Neural Control ◽

Gait Cycle ◽

Balance Control ◽

Vestibular Stimulation ◽

Environmental Constraints ◽

Sporting Events ◽

Complex Environments ◽

Foot Placement ◽

Ankle Inversion ◽

The Right

AbstractHumans need to actively control their upright posture during walking to avoid loss of balance. We do not have a comprehensive theory for how humans regulate balance during walking, especially in complex environments. Balance must be maintained in a variety of contexts including crowded city side-walks, rocky nature trails, walks on the beach, or fast-paced sporting events. The nervous system must process many aspects of the environment to produce an appropriate motor output in order to maintain balance on two legs. We have previously identified three balance mechanisms that young healthy adults use to maintain balance while walking: 1) The ankle roll mechanism, a modulation of ankle inversion/eversion; 2) The foot placement mechanism, a shift of the swing foot placement; and 3) The push-off mechanism, a modulation of the ankle plantarflexion angle during double stance. We know that these mechanisms are interdependent and can be influenced by internal factors such as the phase of the gait cycle and walking cadence. Here we seek to determine whether there are changes in neural control of balance when walking in the presence of environmental constraints. Subjects walked on a selfpaced treadmill while immersed in a virtual environment that provides three different colored pathways. Subjects were instructed not to step in the No-Step Zone, which appeared either on the right or left side of the subject. While walking, subjects received balance perturbations in the form of galvanic vestibular stimulation, providing the sensation of falling sideways, either toward the No-Step zone or toward the Neutral zone on the other side. The results indicate that the use of the balance mechanisms are subtly altered depending on whether the perceived fall is toward the No-Step or the Neutral zone. This experiment provides further evidence that the balance control system during walking is extremely flexible, recruiting multiple mechanisms at different times in the gait cycle to adapt to environmental constraints.

Download Full-text

Biped Walking Control Based on Quadratic Programming and Differential Inequalities

10.48011/asba.v2i1.1029 ◽

2020 ◽

Author(s):

Stella Diniz Urban ◽

Bruno Vilhena Adorno

Keyword(s):

Quadratic Programming ◽

Center Of Mass ◽

Bipedal Walking ◽

Differential Inequalities ◽

Double Support ◽

Cycle Simulation ◽

Minimum Height ◽

Joint Limits ◽

Single Support Phase ◽

Support Phase

This paper presents a novel method to control a bipedal walking based on quadratic programming and differential inequalities using geometric primitives. We allow the center of mass to move anywhere inside the support polygon during the walking cycle, as opposed to classic methods, which usually rely on tracking a desired trajectory for the zero moment point. The constraints keep the robot balance, the pelvis above a minimum height, and prevent the violation of joint limits during the complete walking cycle. Simulation results using the legs of the Poppy humanoid robot show that the trajectories of the closed-loop system converge to the desired center of mass position during the double support phase and the swing foot's trajectories converge to the desired pose during the single support phase while all constraints are obeyed.

Download Full-text