Estimation of Metabolical Costs for Human Locomotion

2005 ◽  
Author(s):  
Werner Schiehlen ◽  
Marko Ackermann
Keyword(s):  
Degrees Of Freedom ◽  
Inverse Dynamics ◽  
Sagittal Plane ◽  
Human Locomotion ◽  
Human Gait ◽  
Joint Torques ◽  
Gait Quality ◽  
Analysis Laboratory ◽  
Muscle Models

Metabolical energy is the chemical energy consumed by skeletal muscles to generate force. This quantity is useful to understand the comfort of human gait and to evaluate, in terms of effort required, the performance of devices or therapies designed to improve gait quality of persons presenting gait disorders. Firstly, this paper presents the frequently used estimations of energy expenditure based lonely on joint torques and mechanical costs obtained by inverse dynamics of passive and active walking devices. Secondly, a more advanced approach is discussed consisting of modeling the musculoskeletal system with Hill-type phenomenological muscle models and computing the metabolical expenditure adopting expressions recently proposed in the literature. As an example a musculoskeletal model of the lower limb in the sagittal plane consisting of thigh, shank and foot with three degrees of freedom and actuated by eight muscles is considered. This model is used to estimate metabolical costs for known normal gait kinematical data obtained in a gait analysis laboratory.

Modeling and Simulation of an Assistive Exoskeleton Leg System with Knee Osteoarthritis and Quadriceps Weakness

2022 ◽  
Author(s):  
Mehmet Iscan ◽  
Cuneyt Yilmaz ◽  
Berkem Vural ◽  
Huseyin Eken
Keyword(s):  
Knee Osteoarthritis ◽  
Feedback Linearization ◽  
Gait Cycle ◽  
Minimum Energy ◽  
Human Locomotion ◽  
Human Gait ◽  
Quadriceps Weakness ◽  
The Common ◽  
Adequate Data

Abstract The most common human locomotion problems such as quadriceps weakness, knee osteoarthritis can be healed up by using exoskeleton mechanisms with proper control systems. However, these kinds of abnormalities cannot be easily modeled in terms of engineering perspectives due to a lack of adequate data or unknown dynamics. Also, nature always seeks minimum energy as well as biology which means that the unknown dynamics can be built by using this phenomenon. In this study, a new system dynamic model had been involved in designing a simple single-legged exoskeleton robot mechanism and its control system to assist partially disabled individuals to improve their quality of locomotion. To determine the specific features of the human gait disorders to interpret their nature in the computer-aided simulation environment, knee osteoarthritis and quadriceps weakness, which are the common types of such problems, have been chosen as the main interests for this study. By using the lower limb model with anthropometric data, the simulations of disorders have been realized on MATLAB Simscape environment which enables us to model the entire exoskeleton system with the 3D parts of the human body. A model of a leg with the disorder was able to be obtained with the utilization of feedback linearization which is one of the examples of minimum principles in the control theory. A proper gait cycle is achieved with the exoskeleton application and separately for the leg, with approximately 10 deg deviation from the natural property in knee flexion. Finally, it can be seen that the system conversion into such problematic cases with or without an exoskeleton system is accomplished.

Comparison of Sprinting With and Without Running-Specific Prostheses Using Optimal Control Techniques

Robotica ◽  
2019 ◽  
Vol 37 (12) ◽  
pp. 2176-2194 ◽  
Author(s):  
Anna Lena Emonds ◽  
Johannes Funken ◽  
Wolfgang Potthast ◽  
Katja Mombaur
Keyword(s):  
Optimal Control ◽  
Degrees Of Freedom ◽  
Sagittal Plane ◽  
Reference Group ◽  
Optimality Criteria ◽  
Mechanical Work ◽  
Step Frequency ◽  
Joint Torques ◽  
Linear Spring ◽  
Multi Body

SummaryThe purpose of our study was to get deeper insights into sprinting with and without running-specific prostheses and to perform a comparison of the two by combining analysis of known motion capture data with mathematical modeling and optimal control problem (OCP) findings. We established rigid multi-body system models with 14 bodies and 16 degrees of freedom in the sagittal plane for one unilateral transtibial amputee and three non-amputee sprinters. The internal joints are powered by torque actuators except for the passive prosthetic ankle joint which is equipped with a linear spring–damper system. For each model, the dynamics of one sprinting trial was reconstructed by solving a multiphase least squares OCP with discontinuities and constraints. We compared the motions of the amputee athlete and the non-amputee reference group by computing characteristic criteria such as the contribution of joint torques, the absolute mechanical work, step frequency and length, among others. By comparing the amputee athlete with the non-amputee athletes, we found reduced activity in the joints of the prosthetic limb, but increased torques and absolute mechanical work in the arms. We also compared the recorded motions to synthesized motions using different optimality criteria and found that the recorded motions are still far from the optimal solutions for both amputee and non-amputee sprinting.

Feedback control of the neuromusculoskeletal system in a forward dynamics simulation of stair locomotion

2009 ◽  
Vol 223 (6) ◽  
pp. 663-675 ◽  
Author(s):  
A Selk Ghafari ◽  
A Meghdari ◽  
G Vossoughi
Keyword(s):  
Feedback Control ◽  
Degrees Of Freedom ◽  
Inverse Dynamics ◽  
Sagittal Plane ◽  
Human Movement ◽  
Stair Climbing ◽  
Dynamics Simulation ◽  
Forward Dynamics ◽  
Control Loops ◽  
The Stability

The aim of this study is to employ feedback control loops to provide a stable forward dynamics simulation of human movement under repeated position constraint conditions in the environment, particularly during stair climbing. A ten-degrees-of-freedom skeletal model containing 18 Hill-type musculotendon actuators per leg was employed to simulate the model in the sagittal plane. The postural tracking and obstacle avoidance were provided by the proportional—integral—derivative controller according to the modulation of the time rate change of the joint kinematics. The stability of the model was maintained by controlling the velocity of the body's centre of mass according to the desired centre of pressure during locomotion. The parameters of the proposed controller were determined by employing the iterative feedback tuning approach to minimize tracking errors during forward dynamics simulation. Simultaneously, an inverse-dynamics-based optimization was employed to compute a set of desired musculotendon forces in the closed-loop simulation to resolve muscle redundancy. Quantitative comparisons of the simulation results with the experimental measurements and the reference muscles' activities illustrate the accuracy and efficiency of the proposed method during the stable ascending simulation.

Kinematic and Kinetic Constraints on Arm, Trunk, and Leg Segments in Target-Reaching Movements

2005 ◽  
Vol 93 (1) ◽  
pp. 352-364 ◽  
Author(s):  
James S. Thomas ◽  
Daniel M. Corcos ◽  
Ziaul Hasan
Keyword(s):  
Degrees Of Freedom ◽  
Neural Control ◽  
Time Course ◽  
Sagittal Plane ◽  
Principal Component ◽  
Joint Torque ◽  
Trunk Flexion ◽  
Joint Torques ◽  
Joint Task ◽  
Task Conditions

We studied target reaching tasks involving not only the arms but also the trunk and legs, which necessitated some trunk flexion. Such tasks can be successfully completed using an infinite number of combinations of segment motions due to the inherent kinematic redundancy with the excessive degrees of freedom (DOFs). Sagittal plane motions of six segments (shank, thigh, pelvis, trunk, humerus, and forearm) and dynamic torques of six joints (ankle, knee, hip, lumbar, shoulder, and elbow) were analyzed separately by principal component (PC) analyses to determine if there was a commonality among the shapes of the respective waveforms. Additionally, PC analyses were used to probe for constraining relationships among the 1) relative magnitudes of segment excursions and 2) the peak-to-peak dynamic joint torques. In summary, at the kinematic level, the tasks are simplified by the use of a single common waveform for all segment excursions with 89.9% variance accounted for (VAF), but with less fixed relationships among the relative scaling of the magnitude of segment excursions (62.2% VAF). However, at the kinetic level, the time course of the dynamic joint torques are not well captured by a single waveform (72.7% VAF), but the tasks are simplified by relatively fixed relationships among the scaling of dynamic joint torque magnitudes across task conditions (94.7% VAF). Taken together, these results indicate that, while the effective DOFs in a multi-joint task are reduced differently at the kinematic and kinetic levels, they both contribute to simplifying the neural control of these tasks.

A phase-reduced neuro-mechanical model for insect locomotion: feed-forward stability and proprioceptive feedback

2010 ◽  
Vol 368 (1930) ◽  
pp. 5087-5104 ◽  
Author(s):  
J. Proctor ◽  
R. P. Kukillaya ◽  
P. Holmes
Keyword(s):  
Degrees Of Freedom ◽  
Muscle Activation ◽  
Phase Oscillators ◽  
Joint Torques ◽  
Insect Locomotion ◽  
Phase Reduction ◽  
Activation Dynamics ◽  
Order Of Magnitude ◽  
Sensory Pathway ◽  
Muscle Models

In earlier work, we have developed an integrated model for insect locomotion that includes a central pattern generator (CPG), nonlinear muscles, hexapedal geometry and a representative proprioceptive sensory pathway. Here, we employ phase reduction and averaging theory to replace 264 ordinary differential equations (ODEs), describing bursting neurons in the CPG, their synaptic connections to motoneurons, muscle activation dynamics and sensory neurons, with 24 one-dimensional phase oscillators that describe motoneuronal activation of agonist–antagonist muscle pairs driving the jointed legs. Reflexive feedback is represented by stereotypical spike trains with rates proportional to joint torques, which change phase relationships among the motoneuronal oscillators. Restriction to the horizontal plane, neglect of leg mass and use of Hill-type muscle models yield a biomechanical body–limb system with only three degrees of freedom, and the resulting hybrid dynamical system involves 30 ODEs: reduction by an order of magnitude. We show that this reduced model captures the dynamics of unperturbed gaits and the effects of an impulsive perturbation as accurately as the original one. Moreover, the phase response and coupling functions provide an improved understanding of reflexive feedback mechanisms.

scholarly journals Validation of the Inverse Dynamic Analysis of Human Gait Using a Forward Dynamics Approach

2013 ◽  
Author(s):  
Rosa Pàmies-Vilà ◽  
Josep M. Font-Llagunes
Keyword(s):  
Dynamic Analysis ◽  
Degrees Of Freedom ◽  
Inverse Dynamics ◽  
Human Gait ◽  
Intermediate Step ◽  
Inverse Dynamic ◽  
Joint Forces ◽  
Simulated Motion ◽  
Dynamical Consistency ◽  
Inverse Dynamics Analysis

One of the aims of the dynamic analysis of human gait is to know the joint forces and torques that the musculoskeletal system produces during the motion. For this purpose, an 18 segment 3D model with 57 degrees of freedom is implemented. The analysis of a captured motion can be addressed by means of forward or inverse dynamic analyses. In this work, both analyses are computed using multibody dynamics techniques. The forward dynamic analysis is carried out with the aim of simulating the movement of the multibody system using the results of the inverse problem as input data. Since the inverse analysis is solved using a dynamically consistent methodology, the forward dynamic analysis allows us to simulate up to the 90% of the gait cycle without any controller. After that, a proportional derivative (PD) controller is implemented to stabilize the system, which gets to simulate the complete captured motion. Moreover, the dynamic contribution of the controller is really low and the simulated motion is extremely close to the original one. The methodology presented allows us to validate the correctness of the inverse dynamics analysis and it is an intermediate step towards the prediction problem: it requires dynamical consistency too, but the uncertainties involved in the problem are lower than in a predictive approach.

Development of a Lower Limb Orthosis to Form Neuromuscular Patterning

2014 ◽  
Author(s):  
Karla A. Camarillo–Gómez ◽  
Gerardo I. Pérez-Soto ◽  
Luis A. Torres-Rico
Keyword(s):  
Quality Of Life ◽  
Control System ◽  
Lower Limb ◽  
Gait Cycle ◽  
Lower Cost ◽  
Sagittal Plane ◽  
Lower Limbs ◽  
Human Gait

In this paper, a lower limb orthosis is proposed to form the human gait neuromuscular patterns in patients with myelomeningocele. The orthosis has two lower limbs of 2–DOF each which reduces the motion of the hip and knee to the sagittal plane. The orthosis are assembled in a back support which also supports the patients weight. The control system for the orthosis allows to reproduce in a repetitive, controlled and autonomous way the human gait cycle at different velocities according to the patient requirements; so that, the neuromuscular patterning can be supervised by a therapist. The development of these orthosis seeks to improve the quality of life of those infants with myelomenigocele and to introduce a lower cost Mexican technology with Mexican anthropometric dimensions.

Optimality Studies of Human Sprinting Motions with and Without Running-Specific Prostheses

2019 ◽  
Vol 16 (03) ◽  
pp. 1940003
Author(s):  
Anna Lena Emonds ◽  
Katja Mombaur
Keyword(s):  
Optimal Control ◽  
Average Velocity ◽  
Degrees Of Freedom ◽  
Sagittal Plane ◽  
Similarity Measures ◽  
Optimality Criteria ◽  
Joint Torques ◽  
Dynamic Constraints ◽  
Specific Objective ◽  
Reaction Forces

Due to the remarkable performances of some amputee athletes, the power of their running-specific prostheses came to the fore of the discussions. The aim of our study was to compare non-amputee and amputee sprinting motions resulting from optimization using combinations of eight optimality criteria with either fixed or free average velocity. For the description of the amputee and the non-amputee athlete, we created rigid multi-body system models with 16 degrees of freedom in the sagittal plane. Each sprinting motion is the solution of a specific optimal control problem with periodicity and dynamic constraints. We found realistic human-like sprinting motions for both the non-amputee and the amputee athlete. We compared the optimized solutions to dynamics-reconstructed solutions from motion capture data and determined similarity measures for each of them. The investigation of the amputee athlete’s joint torques and ground reaction forces revealed that the real amputee athlete does not exploit the functionality of his running-specific prosthesis as much as the model. The optimal control problems with free average velocity generated human-like sprinting motions as well. However, for specific objective functions the velocities exceed the fastest measured velocities in human sprinting.

Liquid State Machine to Generate the Movement Profiles for the Gait Cycle of a Six Degrees-of-Freedom Bipedal Robot in a Sagittal Plane

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Jesús Franco-Robles ◽  
Alejandro De Lucio-Rangel ◽  
Karla A. Camarillo-Gómez ◽  
Gerardo I. Pérez-Soto ◽  
Miguel A. Martínez-Prado
Keyword(s):  
Time Series ◽  
Liquid State ◽  
Degrees Of Freedom ◽  
Gait Cycle ◽  
Sagittal Plane ◽  
State Machine ◽  
Supervised Machine Learning ◽  
Human Gait ◽  
Bipedal Robot ◽  
Six Degrees Of Freedom

Abstract In this paper, an approach based on a liquid state machine (LSM) to compute the movement profiles to achieve a gait pattern subject to different variations in its trajectory is presented. At the same time, the position of the zero moment point (ZMP) to determine the stability of the six degrees-of-freedom (6DOF) bipedal robot in the sagittal plane during the gait cycle is calculated. The system is constructed as a supervised machine learning model. The time series of the oscillating foot trajectory obtained by direct kinematics with a multilayer perceptron neural network (MLP), to strengthen the kinematic model, is considered as input values for training. The target movement profiles are acquired of a human gait cycle analysis in three different scenarios: normal gait, climbing stairs, and descending stairs. In training, this model also gets the trajectories of the ZMP position during the gait cycle, as target time series. The LSM formed by spiking neurons, considered as third-generation neural networks, is compared in the accuracy of prediction, by the dynamic time warping (DTW) technique and correlation analysis, against the human gait analysis database. With this neuronal system, the joint positions to generate a trajectory of the oscillating foot and the ZMP position of the bipedal in the sagittal plane in different scenarios are obtained, proving the robustness of the LSM.

Modeling of Human Posturokinetic Movements by a Linear Feedback System: Relations among Feedback Coefficients

2002 ◽  
Vol 95 (1) ◽  
pp. 308-318 ◽  
Author(s):  
Karen Roux ◽  
Christian Gentil ◽  
Alexander Grishin
Keyword(s):  
Neural Control ◽  
Inverse Dynamics ◽  
Sagittal Plane ◽  
Movement Analysis ◽  
Feedback System ◽  
Whole Body ◽  
Linear Feedback ◽  
State Variables ◽  
Joint Torques ◽  
Angular Velocities

This study describes a method of modeling human trunk and whole body backward bending and suggests a possible neural control strategy. The hypothesis was that the control system can be modeled as a linear feedback system, in which the torque acting at a given joint is a function of the state variables (angular positions and angular velocities). The linear system enabled representation of the feedback system by a gain matrix. The matrix was computed from the kinematics recorded by a movement analysis system and from the joint torques calculated by inverse dynamics. To validate the control model, a comparison was made between the angular kinematics yielded by the model and the experimental data. Moreover, for all subjects, the same relationships between feedback coefficients were found although gain values were different. The study showed that the feedback system is an appropriate model of the strategy from performing an accurate controlled trunk or whole body backward bending in the sagittal plane.

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