scholarly journals Force direction patterns promote whole body stability even in hip-flexed walking, but not upper body stability in human upright walking

2017 ◽  
Vol 473 (2207) ◽  
pp. 20170404 ◽  
Author(s):  
Roy Müller ◽  
Christian Rode ◽  
Soran Aminiaghdam ◽  
Johanna Vielemeyer ◽  
Reinhard Blickhan
Keyword(s):  
Inverted Pendulum ◽  
Focal Point ◽  
Metabolic Cost ◽  
Body Motion ◽  
Upper Body ◽  
Whole Body ◽  
Centre Of Mass ◽  
General Relevance ◽  
Force Direction ◽  
Reaction Forces

Directing the ground reaction forces to a focal point above the centre of mass of the whole body promotes whole body stability in human and animal gaits similar to a physical pendulum. Here we show that this is the case in human hip-flexed walking as well. For all upper body orientations (upright, 25°, 50°, maximum), the focal point was well above the centre of mass of the whole body, suggesting its general relevance for walking. Deviations of the forces' lines of action from the focal point increased with upper body inclination from 25 to 43 mm root mean square deviation (RMSD). With respect to the upper body in upright gait, the resulting force also passed near a focal point (17 mm RMSD between the net forces' lines of action and focal point), but this point was 18 cm below its centre of mass. While this behaviour mimics an unstable inverted pendulum, it leads to resulting torques of alternating sign in accordance with periodic upper body motion and probably provides for low metabolic cost of upright gait by keeping hip torques small. Stabilization of the upper body is a consequence of other mechanisms, e.g. hip reflexes or muscle preflexes.

Efficient ZMP Formulation and Effective Whole-Body Motion Generation for a Human-Like Mechanism

2008 ◽  
Author(s):  
Joo H. Kim ◽  
Yujiang Xiang ◽  
Rajankumar Bhatt ◽  
Jingzhou Yang ◽  
Hyun-Joon Chung ◽  
...  
Keyword(s):  
Dynamic Balance ◽  
Body Motion ◽  
Whole Body ◽  
Motion Generation ◽  
Standing Posture ◽  
Upright Standing ◽  
Task Requirements ◽  
Reaction Forces ◽  
Zero Moment ◽  
Physics Based Simulation

An approach of generating dynamic biped motions of a human-like mechanism is proposed. An alternative and efficient formulation of the Zero-Moment Point for dynamic balance and the approximated ground reaction forces/moments are derived from the resultant reaction loads, which includes the gravity, the externally applied loads, and the inertia. The optimization problem is formulated to address the redundancy of the human task, where the general biped and task-specific constraints are imposed depending on the task requirements. The proposed method is fully predictive and generates physically feasible human-like motions from scratch; it does not require any input reference from motion capture or animation. The resulting generated motions demonstrate how a human-like mechanism reacts effectively to different external load conditions in performing a given task by showing realistic features of cause and effect. In addition, the energy-optimality of the upright standing posture is numerically verified among infinite feasible static biped postures without self contact. The proposed formulation is beneficial to motion planning, control, and physics-based simulation of humanoids and human models.

Whole-Body Human-to-Humanoid Motion Imitation

2013 ◽  
Vol 479-480 ◽  
pp. 617-621
Author(s):  
Hsien I Lin ◽  
Zan Sheng Chen
Keyword(s):  
Degrees Of Freedom ◽  
Humanoid Robot ◽  
Optimal Solution ◽  
Human Motion ◽  
Body Motion ◽  
Upper Body ◽  
Whole Body ◽  
Nao Robot ◽  
Novel Approach ◽  
Intuitive Method

Human-to-Humanoid motion imitation is an intuitive method to teach a humanoid robot how to act by human demonstration. For example, teaching a robot how to stand is simply showing the robot how a human stands. Much of previous work in motion imitation focuses on either upper-body or lower-body motion imitation. In this paper, we propose a novel approach to imitate human whole-body motion by a humanoid robot. The main problem of the proposed work is how to control robot balance and keep the robot motion as similar as taught human motion simultaneously. Thus, we propose a balance criterion to assess how well the root can balance and use the criterion and a genetic algorithm to search a sub-optimal solution, making the root balanced and its motion similar to human motion. We have validated the proposed work on an Aldebaran Robotics NAO robot with 25 degrees of freedom. The experimental results show that the root can imitate human postures and autonomously keep itself balanced.

scholarly journals Does an inverted pendulum model represent the gait of individuals with unilateral transfemoral amputation while walking over level ground?

2018 ◽  
Vol 43 (2) ◽  
pp. 221-226 ◽  
Author(s):  
Gerda Strutzenberger ◽  
Nathalie Alexander ◽  
Alan De Asha ◽  
Hermann Schwameder ◽  
Cleveland Thomas Barnett
Keyword(s):  
Gait Cycle ◽  
Inverted Pendulum ◽  
Metabolic Cost ◽  
Centre Of Mass ◽  
Transfemoral Amputation ◽  
Prosthetic Device ◽  
Relative Time ◽  
Prosthetic Limb ◽  
Inverted Pendulum Model ◽  
Pendulum Model

Background: An inverted pendulum model represents the mechanical function of able-bodied individuals walking accurately, with centre of mass height and forward velocity data plotting as sinusoidal curves, 180° out of phase. Objectives: This study investigated whether the inverted pendulum model represented level gait in individuals with a unilateral transfemoral amputation. Study Design: Controlled trial. Methods: Kinematic and kinetic data from 10 individuals with unilateral transfemoral amputation and 15 able-bodied participants were recorded during level walking. Results: During level walking, the inverted pendulum model described able-bodied gait well throughout the gait cycle, with median relative time shifts between centre of mass height and velocity maxima and minima between 1.2% and 1.8% of gait cycle. In the group with unilateral transfemoral amputation, the relative time shift was significantly increased during the prosthetic-limb initial double-limb support phase by 6.3%. Conclusion: The gait of individuals with unilateral transfemoral amputation shows deviation from a synchronous inverted pendulum model during prosthetic-limb stance. The reported divergence may help explain such individuals’ increased metabolic cost of gait. Temporal divergence of inverted pendulum behaviour could potentially be utilised as a tool to assess the efficacy of prosthetic device prescription. Clinical relevance The size of the relative time shifts between centre of mass height and velocity maxima and minima could potentially be used as a tool to quantify the efficacy of innovative prosthetic device design features aimed at reducing the metabolic cost of walking and improving gait efficiency in individuals with amputation.

scholarly journals Walking on a moving surface: energy-optimal walking motions on a shaky bridge and a shaking treadmill can reduce energy costs below normal

2015 ◽  
Vol 471 (2174) ◽  
pp. 20140662 ◽  
Author(s):  
Varun Joshi ◽  
Manoj Srinivasan
Keyword(s):  
Numerical Optimization ◽  
Energy Use ◽  
Metabolic Cost ◽  
Body Motion ◽  
Metabolic Energy ◽  
Upper Body ◽  
Biped Walking ◽  
Walking Motion ◽  
Mass Spring ◽  
Millennium Bridge

Understanding how humans walk on a surface that can move might provide insights into, for instance, whether walking humans prioritize energy use or stability. Here, motivated by the famous human-driven oscillations observed in the London Millennium Bridge, we introduce a minimal mathematical model of a biped, walking on a platform (bridge or treadmill) capable of lateral movement. This biped model consists of a point-mass upper body with legs that can exert force and perform mechanical work on the upper body. Using numerical optimization, we obtain energy-optimal walking motions for this biped, deriving the periodic body and platform motions that minimize a simple metabolic energy cost. When the platform has an externally imposed sinusoidal displacement of appropriate frequency and amplitude, we predict that body motion entrained to platform motion consumes less energy than walking on a fixed surface. When the platform has finite inertia, a mass- spring-damper with similar parameters to the Millennium Bridge, we show that the optimal biped walking motion sustains a large lateral platform oscillation when sufficiently many people walk on the bridge. Here, the biped model reduces walking metabolic cost by storing and recovering energy from the platform, demonstrating energy benefits for two features observed for walking on the Millennium Bridge: crowd synchrony and large lateral oscillations.

scholarly journals Constructing predictive models of human running

2015 ◽  
Vol 12 (103) ◽  
pp. 20140899 ◽  
Author(s):  
Horst-Moritz Maus ◽  
Shai Revzen ◽  
John Guckenheimer ◽  
Christian Ludwig ◽  
Johann Reger ◽  
...  
Keyword(s):  
Predictive Models ◽  
Inverted Pendulum ◽  
Human Locomotion ◽  
Three Dimensions ◽  
Centre Of Mass ◽  
Starting Point ◽  
Reaction Forces ◽  
Using Data ◽  
Human Running ◽  
Reduced State

Running is an essential mode of human locomotion, during which ballistic aerial phases alternate with phases when a single foot contacts the ground. The spring-loaded inverted pendulum (SLIP) provides a starting point for modelling running, and generates ground reaction forces that resemble those of the centre of mass (CoM) of a human runner. Here, we show that while SLIP reproduces within-step kinematics of the CoM in three dimensions, it fails to reproduce stability and predict future motions. We construct SLIP control models using data-driven Floquet analysis, and show how these models may be used to obtain predictive models of human running with six additional states comprising the position and velocity of the swing-leg ankle. Our methods are general, and may be applied to any rhythmic physical system. We provide an approach for identifying an event-driven linear controller that approximates an observed stabilization strategy, and for producing a reduced-state model which closely recovers the observed dynamics.

Effect of Having A-Priori Knowledge of the Floor's Contaminant Condition on the Biomechanics of Slips

2002 ◽  
Vol 46 (13) ◽  
pp. 1181-1185 ◽  
Author(s):  
Rakié Cham ◽  
Brian Moyer ◽  
Mark S. Redfern
Keyword(s):  
A Priori ◽  
Young Male ◽  
Body Motion ◽  
Whole Body ◽  
A Priori Knowledge ◽  
Heel Contact ◽  
Reaction Forces ◽  
Hip Flexion ◽  
Gait Disturbances ◽  
Priori Knowledge

Injuries and deaths are often the result of slips/falls. The perceived danger of slipping affects gait biomechanics. This paper investigated the effect of having a-priori knowledge of the floor's contaminant condition on the biomechanics of slips. Five healthy young male subjects donned a safety harness and walked across a walkway, while ground reaction forces and whole body motion were recorded bilaterally at 60 Hz. Slips on soapy floors occurred under 3 “knowledge” conditions: (1) unexpected slips, (2) slips when uncertain of the contaminant condition, and (3) slips when walking onto known contaminated floors. in (2) and (3), i.e. anticipation of slippery surfaces, subjects generated proactive reactions (reduced stance duration and foot angle at heel contact as well as greater hip flexion) compared to unexpected conditions in (1). Those reactions reduced slip potential but also minimized gait disturbances (reduced slip distance and sliding velocity of the heel) when a slip occurred.

scholarly journals Robots that look like humans: A brief look into humanoid robotics

2018 ◽  
Author(s):  
Eiichi Yoshida
Keyword(s):  
Degrees Of Freedom ◽  
Large Scale ◽  
Humanoid Robots ◽  
Pattern Generation ◽  
Human Robot Interaction ◽  
Cognitive Robotics ◽  
Body Motion ◽  
Upper Body ◽  
Whole Body ◽  
Robot Interaction

This article provides a brief overview of the technology of humanoid robots. First, historical development and hardware progress are presented mainly on human-size full-body biped humanoid robots, together with progress in pattern generation of biped locomotion. Then, «whole-body motion» – coordinating leg and arm movements to fully leverage humanoids’ high degrees of freedom – is presented, followed by its applications in fields such as device evaluation and large-scale assembly. Upper-body humanoids with a mobile base, which are mainly utilized for research on human-robot interaction and cognitive robotics, are also introduced before addressing current issues and perspectives.

scholarly journals Control of Pushing and Pulling Motion of a Wheeled Inverted Pendulum Based on a Reduced Order Observer

2011 ◽  
Vol 2-3 ◽  
pp. 74-79
Author(s):  
Luis Canete ◽  
Sunao Kimura ◽  
Takayuki Takahashi
Keyword(s):  
Disturbance Observer ◽  
Inverted Pendulum ◽  
Reaction Force ◽  
Initial Step ◽  
Body Motion ◽  
Whole Body ◽  
Reduced Order ◽  
Wheeled Inverted Pendulum ◽  
Reduced Order Observer ◽  
Pushing And Pulling

In this paper the control of the I-PENTAR, a wheeled inverted pendulum type robot being developed by the authors, for pushing and pulling a cart is examined. To control the movement of the object is being pushed or pulled, information regarding several external parameters, eg. Mass of the object and friction components, must be considered. In most cases these parameters are not known before hand or may change. One method of compensating for these unknown or changing external parameters is to represent them as an equivalent reaction force from the object. Our first subject of this research is to design a disturbance observer to estimate and compensate the equivalent force. Another situation is of pushing and pulling a cart with the inverted pendulum type robot traversing an inclined plane. As an initial step to solving this problem in this paper, a force application method using whole body motion of the inverted pendulum type robot is proposed. The whole body motion means changing the balance of the robot to attain a certain desired force. During application of this force the robot must remain in its stabilized or balanced state. For an inverted pendulum type robot, this instantly poses a major problem. To solve the problem, a reduced order disturbance observer is used in this paper to estimate the force applied by the robot. On the other hand, I-PENTAR is targeted for environments where it can interact with humans and so safety is a major concern. For example, in the event that an obstacle bumps the robot as it is pushing the cart, a large and sudden force estimator based on the disturbance observer is also built into the controller. Simulation and experiments using the reduced order disturbance observer and evaluation of the whole body motion force control are presented.

Sign in / Sign up

Export Citation Format

Share Document