Performance Analysis and Feedback Control of ATRIAS, A Three-Dimensional Bipedal Robot

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Alireza Ramezani ◽  
Jonathan W. Hurst ◽  
Kaveh Akbari Hamed ◽  
J. W. Grizzle
Keyword(s):  
Energy Efficiency ◽  
Dynamic Model ◽  
Degrees Of Freedom ◽  
Sagittal Plane ◽  
Center Of Mass ◽  
Three Dimensional ◽  
The Body ◽  
Energetic Efficiency ◽  
Natural Terrain ◽  
Walking Speeds

This paper develops feedback controllers for walking in 3D, on level ground, with energy efficiency as the performance objective. Assume The Robot Is A Sphere (ATRIAS) 2.1 is a new robot that has been designed for the study of 3D bipedal locomotion, with the aim of combining energy efficiency, speed, and robustness with respect to natural terrain variations in a single platform. The robot is highly underactuated, having 6 actuators and, in single support, 13 degrees of freedom. Its sagittal plane dynamics are designed to embody the spring loaded inverted pendulum (SLIP), which has been shown to provide a dynamic model of the body center of mass during steady running gaits of a wide diversity of terrestrial animals. A detailed dynamic model is used to optimize walking gaits with respect to the cost of mechanical transport (CMT), a dimensionless measure of energetic efficiency, for walking speeds ranging from 0.5 (m/s) to 1.4 (m/s). A feedback controller is designed that stabilizes the 3D walking gaits, despite the high degree of underactuation of the robot. The 3D results are illustrated in simulation. In experiments on a planarized (2D) version of the robot, the controller yielded stable walking.

scholarly journals Sensorimotor feedback based on task-relevant error robustly predicts temporal recruitment and multidirectional tuning of muscle synergies

2013 ◽  
Vol 109 (1) ◽  
pp. 31-45 ◽  
Author(s):  
Seyed A. Safavynia ◽  
Lena H. Ting
Keyword(s):  
Sagittal Plane ◽  
Balance Control ◽  
Center Of Mass ◽  
The Body ◽  
Muscle Synergy ◽  
Muscle Synergies ◽  
Muscle Coordination ◽  
Initial State ◽  
Sensorimotor Feedback ◽  
Task Level

We hypothesized that motor outputs are hierarchically organized such that descending temporal commands based on desired task-level goals flexibly recruit muscle synergies that specify the spatial patterns of muscle coordination that allow the task to be achieved. According to this hypothesis, it should be possible to predict the patterns of muscle synergy recruitment based on task-level goals. We demonstrated that the temporal recruitment of muscle synergies during standing balance control was robustly predicted across multiple perturbation directions based on delayed sensorimotor feedback of center of mass (CoM) kinematics (displacement, velocity, and acceleration). The modulation of a muscle synergy's recruitment amplitude across perturbation directions was predicted by the projection of CoM kinematic variables along the preferred tuning direction(s), generating cosine tuning functions. Moreover, these findings were robust in biphasic perturbations that initially imposed a perturbation in the sagittal plane and then, before sagittal balance was recovered, perturbed the body in multiple directions. Therefore, biphasic perturbations caused the initial state of the CoM to differ from the desired state, and muscle synergy recruitment was predicted based on the error between the actual and desired upright state of the CoM. These results demonstrate that that temporal motor commands to muscle synergies reflect task-relevant error as opposed to sensory inflow. The proposed hierarchical framework may represent a common principle of motor control across motor tasks and levels of the nervous system, allowing motor intentions to be transformed into motor actions.

scholarly journals Effect of Leg Dominance on The Center-of-Mass Kinematics During an Inside-of-the-Foot Kick in Amateur Soccer Players

2014 ◽  
Vol 42 (1) ◽  
pp. 51-61 ◽  
Author(s):  
Matteo Zago ◽  
Andrea Francesco Motta ◽  
Andrea Mapelli ◽  
Isabella Annoni ◽  
Christel Galvani ◽  
...  
Keyword(s):  
Body Movement ◽  
Center Of Mass ◽  
Three Dimensional ◽  
The Body ◽  
Soccer Players ◽  
Upper Body ◽  
Whole Body ◽  
Movement Velocity ◽  
Ground Support ◽  
Analysis System

Abstract Soccer kicking kinematics has received wide interest in literature. However, while the instep-kick has been broadly studied, only few researchers investigated the inside-of-the-foot kick, which is one of the most frequently performed techniques during games. In particular, little knowledge is available about differences in kinematics when kicking with the preferred and non-preferred leg. A motion analysis system recorded the three-dimensional coordinates of reflective markers placed upon the body of nine amateur soccer players (23.0 ± 2.1 years, BMI 22.2 ± 2.6 kg/m2), who performed 30 pass-kicks each, 15 with the preferred and 15 with the non-preferred leg. We investigated skill kinematics while maintaining a perspective on the complete picture of movement, looking for laterality related differences. The main focus was laid on: anatomical angles, contribution of upper limbs in kick biomechanics, kinematics of the body Center of Mass (CoM), which describes the whole body movement and is related to balance and stability. When kicking with the preferred leg, CoM displacement during the ground-support phase was 13% higher (p<0.001), normalized CoM height was 1.3% lower (p<0.001) and CoM velocity 10% higher (p<0.01); foot and shank velocities were about 5% higher (p<0.01); arms were more abducted (p<0.01); shoulders were rotated more towards the target (p<0.01, 6° mean orientation difference). We concluded that differences in motor control between preferred and non-preferred leg kicks exist, particularly in the movement velocity and upper body kinematics. Coaches can use these results to provide effective instructions to players in the learning process, moving their focus on kicking speed and upper body behavior

A Nonlinear Oscillator Model to Generate Lateral Walking Force on a Rigid Flat Surface

2018 ◽  
Vol 18 (02) ◽  
pp. 1850020 ◽  
Author(s):  
Prakash Kumar ◽  
Anil Kumar ◽  
Silvano Erlicher
Keyword(s):  
Nonlinear Oscillator ◽  
Perturbation Technique ◽  
Center Of Mass ◽  
Reaction Force ◽  
Lateral Force ◽  
The Body ◽  
Model Parameters ◽  
Lateral Direction ◽  
Van Der Pol Oscillators ◽  
Walking Speeds

This study proposes a single degree of freedom nonlinear oscillator to model the lateral movement of the body center of mass of a pedestrian walking on a flat rigid surface. Experimentally recorded ground reaction force of a dozen of pedestrians in the lateral direction is used to develop the model. In detail, the hardening and softening effects are observed in the stiffness curve as well as higher odd harmonics are present in the frequency spectrum of the lateral force signals. The proposed oscillator is a modification of the Rayleigh and the Van der Pol oscillators with additional nonlinear softening and hardening terms. To obtain an approximation of the limit cycle of the oscillator and its stability, two methods are studied: the energy balance method and the Lindstedt–Poincare perturbation technique. The experimental force signals of pedestrians at four different walking speeds are used for the identification of the values of the model parameters. The results obtained from the proposed model show a good agreement with the experimental ones.

Gait style as an etiology to chronic postural pain. Part II. Postural compensatory process

1993 ◽  
Vol 83 (11) ◽  
pp. 615-624 ◽  
Author(s):  
HJ Dananberg
Keyword(s):  
Kinetic Energy ◽  
Sagittal Plane ◽  
Center Of Mass ◽  
Metatarsophalangeal Joint ◽  
Specific Pattern ◽  
The Body ◽  
First Metatarsophalangeal Joint ◽  
The Past ◽  
Compensatory Process ◽  
Methods Of Treatment

The body is designed to pull the center of mass over a single pivotal site formed by dorsiflexion of the first metatarsophalangeal joint. If this response dorsiflexion motion is blocked by functional hallux limitus, then the kinetic energy, which is created for this motion, must somehow be dissipated. The process by which this dissipation occurs creates a specific pattern of compensations which, in the past, has been seen as primary motions unrelated to sagittal plane blockade. These compensatory motions are described along with a brief section concerning the methods of treatment.

Analysis of Foot Kinematics with Unstable Sole Structure Using Oxford Foot Model

2017 ◽  
Vol 34 ◽  
pp. 1-9 ◽  
Author(s):  
Ying Yue Zhang ◽  
Gusztáv Fekete ◽  
Justin Fernandez ◽  
Yao Dong Gu
Keyword(s):  
Sagittal Plane ◽  
Plantar Flexion ◽  
Three Dimensional ◽  
Frontal Plane ◽  
The Body ◽  
Control Effect ◽  
Foot Kinematics ◽  
Foot Model ◽  
Contrast Group ◽  
Oxford Foot Model

To determine the influence of the unstable sole structure on foot kinematics and provide theoretical basis for further application.12 healthy female subjects walked through a 10-meter experimental channel with normal speed wearing experimental shoes and control shoes respectively at the gait laboratory. Differences between the groups in triplanar motion of the forefoot, rearfoot and hallux during walking were evaluated using a three-dimensional motion analysis system incorporating with Oxford Foot Model (OFM). Compare to contrast group, participants wearing experimental shoes demonstrated greater peak forefoot dorsiflexion, forefoot supination and longer halluces plantar flexion time in support phase. Additionally, participants with unstable sole structure also demonstrated smaller peak forefoot plantarflexion, rearfoot dorsiflexion and range of joint motion in sagittal plane and frontal plane.. The difference mainly appeared in sagittal and frontal plane. With a stimulation of unstable, it may lead to the reinforcement of different flexion between middle and two ends of the foot model. The greater forefoot supination is infered that the unstable element structure may affect the forefoot motion on the frontal plane and has a control effect to strephexopodia people. The stimulation also will reflexes reduce the range of rearfoot motion in sagittal and frontal planes to control the gravity center of the body and keep a steady state in the process of walking.

A Three-Dimensional Dynamic Model for Determining the Equilibrium Configurations of Buoyantly Unstable Icebergs

1990 ◽  
Vol 112 (3) ◽  
pp. 253-262
Author(s):  
R. G. Jessup ◽  
S. Venkatesh
Keyword(s):  
Dynamic Model ◽  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Static Potential ◽  
Initial State ◽  
Model Simulations ◽  
Six Degrees Of Freedom ◽  
Equilibrium Configurations ◽  
Variation Range

This paper describes a dynamic model developed for the purpose of determining the final equilibrium configurations of buoyantly unstable icebergs. The model places no restrictions on the size, shape, or dimensionality of the iceberg, or on the variation range of the configuration coordinates. Furthermore, it includes all six degrees of freedom and is based on a Lagrangian formulation of the dynamic equations of motion. It can be used to advantage in those situations in which the iceberg has a complicated potential function and can acquire enough momentum and kinetic energy in the initial phase of its motion to make its final configuration uncertain on the basis of a static potential analysis. The behavior of the model is examined through several model simulations. The sensitivity of the final equilibrium position to the initial orientation and shape of the iceberg is clearly evident in the model simulations. Model simulations also show that when an iceberg is released from a nonequilibrium initial state, the time taken for it to settle down varies from about 40 s for a growler to nearly 400 s for a large iceberg. While these absolute times may change with better parameterization of the forces, the relative variations with iceberg size are likely to be preserved.

Estimation of Balance Stability States for Legged Robotic Systems

2016 ◽  
Author(s):  
Carlotta Mummolo ◽  
Luigi Mangialardi ◽  
Joo H. Kim
Keyword(s):  
State Space ◽  
Degrees Of Freedom ◽  
Center Of Mass ◽  
Stability Boundary ◽  
Three Dimensional ◽  
Quantitative Measure ◽  
Initial Position ◽  
Robotic Systems ◽  
The Given ◽  
Balance Stability

A three-dimensional criterion is provided for the estimation of balance stability states of legged robotic systems subject to various constraints. A general framework is established to evaluate the balance stability boundary of a given system in the state space of Center of Mass (COM) Cartesian position and velocity. For each assigned COM initial position, an optimization-based iterative algorithm finds the minimum and maximum COM initial velocity that the system can handle along a given direction, such that it maintains the capability to reach a final static equilibrium. The resulting set of velocity extrema constitutes the system’s balance stability boundary, which represents the sufficient condition to estimate falling states versus balanced states, according to the definitions provided herein. The COM state space domain identified with this approach contains all possible balanced states for the given legged system, with respect to the necessary physical, balancing, and design constraints. The balance state estimation is demonstrated for 1- and 2-degrees of freedom planar legged systems in single support. The domain identified by the balance stability boundary can be used as a “map” for the given legged system in which the distance from a given state to the domain boundaries can provide a quantitative measure of balance stability/instability.

Stability and Robustness of a 3D Slip Model for Walking Using Lateral Leg Placement Control

2012 ◽  
Author(s):  
Dominik Budday ◽  
Fabian Bauer ◽  
Justin Seipel
Keyword(s):  
Humanoid Robot ◽  
Performance Test ◽  
Control Mechanism ◽  
Sagittal Plane ◽  
Control Strategies ◽  
Center Of Mass ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Slip Model ◽  
The Stability

The SLIP model has shown a way to easily represent the center of mass dynamics of human walking and running. For 2D motions in the sagittal plane, the model shows self-stabilizing effects that can be very useful when designing a humanoid robot. However, this self-stability could not be found in three-dimensional running, but simple control strategies achieved stabilization of running in three dimensions. Yet, 3D walking with SLIP has not been analyzed to the same extent. In this paper we show that three-dimensional humanoid SLIP walking is also unstable, but can be stabilized using the same strategy that has been successful for running. It is shown that this approach leads to the desired periodic solutions. Furthermore, the influence of different parameters on stability and robustness is examined. Using a performance test to simulate the transition from an upright position to periodic walking we show that the stability is robust. With a comparison of common models for humanoid walking and running it is shown that the simple control mechanism is able to achieve stable solutions for all models, providing a very general approach to this problem. The derived results point out preferable parameters to increase robustness promising the possibility of successfully realizing a humanoid walking robot based on 3D SLIP.

Design, dynamic modelling and control of a bio-inspired helical swimming microrobot with three-dimensional manoeuvring

2016 ◽  
Vol 39 (7) ◽  
pp. 1037-1046 ◽  
Author(s):  
Hossein Nourmohammadi ◽  
Jafar Keighobadi ◽  
Mohsen Bahrami
Keyword(s):  
Feedback Linearization ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Dynamic Modelling ◽  
Linearization Method ◽  
The Body ◽  
Motion Trajectories ◽  
Mems Technology ◽  
Propulsion Force ◽  
Resistive Force Theory

Biomedical applications of swimming microrobots comprising of drug delivery, microsurgery and disease monitoring make the research more interesting in MEMS technology. In this paper, inspired by the flagellar motion of microorganisms like bacteria and also considering the recent attempts in one/two-dimensional modelling of swimming microrobots, a three degrees-of-freedom swimming microrobot is developed. In the proposed design, the body of the swimming microrobot is driven by multiple prokaryotic flagella which produce a propulsion force through rotating in the fluid media. The presented swimming microrobot has the capability of doing three-dimensional manoeuvres and moving along three-dimensional reference paths. In this paper, following dynamical modelling of the microrobot motion, a suitable controller is designed for path tracking purposes. Based on the resistive-force theory, the generated propulsion force by the flagella is modelled. The feedback linearization method is applied for perfect tracking control of the swimming microrobot on the desired motion trajectories. It is seen that, by the use of three flagella, the microrobot is able to perform three-dimensional manoeuvres. From the simulation results, the tracking performance of the designed control system is perfectly guaranteed which enables the microrobot to perform the desired three-dimensional manoeuvres and follow the desired trajectory.

scholarly journals EFFECTS OF THE SCHROTH METHOD IN CHILDREN WITH IDIOPATHIC SCOLIOSIS

2019 ◽  
Vol 16 (2) ◽  
pp. 749
Author(s):  
Bojan Jorgić ◽  
Petra Mančić ◽  
Saša Milenković ◽  
Nikola Jevtić ◽  
Mladen Živković
Keyword(s):  
Idiopathic Scoliosis ◽  
Sagittal Plane ◽  
Three Dimensional ◽  
Exercise Program ◽  
Frontal Plane ◽  
Axial Rotation ◽  
The Body ◽  
Scoliosis Correction ◽  
Lateral Curvature ◽  
Positive Effect

Scoliosis is a multifactorial three-dimensional (3D) spinal deformation which always includes elementary deformations on three planes: a lateral curvature on the frontal plane, loss of natural physiological curvature on the sagittal plane and, in most cases, increase of lordosis in the lumbosacral joint (hyperlordosis), and a (very typical) vertebral axial rotation on the horizontal plane. One of the best methods in scoliosis correction is the Schroth method. In view of the above, the objective of this study is to identify the effects of the Schroth method on correcting functional-motor status in children with adolescent idiopathic scoliosis (IS). The participant sample comprised 20 children, of an average age of 14.5, who took part in the 10-day Schroth Camp. The following measure instruments were used for the assessment of the effect of the Schroth method: the Sorensen test, the Sit-and-reach test, and height assessment. Statistically significant improvements were identified across the results of all three tests, for the Sorensen test: 45.6±19.29 s, the Sit-and-reach test: 4.05±2.25 cm, and height 1.4±0.66 cm. It can be concluded that the conducted Schroth method exercise program exerted a positive effect on improving motor functionality, as well as enhancing flexibility and isometric endurance of the lumbar extensors of the spine. Additionally, there was an increase in height, which indicates a positive effect in terms of the functionality and symmetry of the left and right sides of the body, and in terms of improved posture on the frontal and sagittal planes.

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