scholarly journals Ankle Joint Torque Prediction Based on Surface Electromyographic and Angular Velocity Signals

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 217681-217687
Author(s):  
Chanjuan Su ◽  
Shurong Chen ◽  
Haiyan Jiang ◽  
Yan Chen
Keyword(s):  
Angular Velocity ◽  
Ankle Joint ◽  
Joint Torque

scholarly journals Joint torque and velocity optimization for a redundant leg of quadruped robot

2017 ◽  
Vol 14 (5) ◽  
pp. 172988141773189 ◽  
Author(s):  
Taihui Zhang ◽  
Honglei An ◽  
Hongxu Ma
Keyword(s):  
Angular Velocity ◽  
Sagittal Plane ◽  
Load Capacity ◽  
Optimization Criterion ◽  
Quadruped Robot ◽  
Joint Torque ◽  
Quadratic Program ◽  
Hydraulic Actuator ◽  
Joint Torques ◽  
Physical Limitations

Hydraulic actuated quadruped robot similar to BigDog has two primary performance requirements, load capacity and walking speed, so that it is necessary to balance joint torque and joint velocity when designing the dimension of single leg and controlling its motion. On the one hand, because there are three joints per leg on sagittal plane, it is necessary to firstly optimize the distribution of torque and angular velocity of every joint on the basis of their different requirements. On the other hand, because the performance of hydraulic actuator is limited, it is significant to keep the joint torque and angular velocity in actuator physical limitations. Therefore, it is essential to balance the joint torque and angular velocity which have negative correlation under the condition of constant power of the hydraulic actuator. The main purpose of this article is to optimize the distribution of joint torques and velocity of a redundant single leg with joint physical limitations. Firstly, a modified optimization criterion combining joint torques with angular velocity that takes both support phase and flight phase into account is proposed, and then the modified optimization criterion is converted into a normal quadratic programming problem. A kind of recurrent neural network is used to solve the quadratic program problem. This method avoids tremendous matrix inversion and fits for time-varying system. The achieved optimized distribution of joint torques and velocity is useful for aiding mechanical design and the following motion control. Simulation results presented in this article confirm the efficiency of this optimization algorithm.

scholarly journals A Custom-Made Lower Limb Dynamometer for Assessing Ankle Joint Torque in Humans: Calibration and Measurement Procedures

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 135
Author(s):  
Iulia Iovanca Drăgoi ◽  
Florina Georgeta Popescu ◽  
Teodor Petrița ◽  
Romulus Fabian Tatu ◽  
Cosmina Ioana Bondor ◽  
...  
Keyword(s):  
Ankle Joint ◽  
Plantar Flexion ◽  
Calibration Procedure ◽  
Measurement Procedure ◽  
Joint Torque ◽  
Ankle Torque ◽  
Offset Voltage ◽  
Interclass Correlation ◽  
Custom Made ◽  
Measurement Protocol

Custom-made dynamometry was shown to objectively analyze human muscle strength around the ankle joint with accuracy, easy portability and low costs. This paper describes the full method of calibration and measurement setup and the measurement procedure when capturing ankle torque for establishing reliability of a portable custom-built electronic dynamometer. After considering the load cell offset voltage, the pivotal position was determined, and calibration with loads followed. Linear regression was used for calculating the proportionality constant between torque and measured voltage. Digital means were used for data collection and processing. Four healthy consenting participants were enrolled in the study. Three consecutive maximum voluntary isometric contractions of five seconds each were registered for both feet during plantar flexion/dorsiflexion, and ankle torque was then calculated for three ankle inclinations. A calibration procedure resulted, comprising determination of the pivotal axis and pedal constant. Using the obtained data, a measurement procedure was proposed. Obtained contraction time graphs led to easier filtering of the results. When calculating the interclass correlation, the portable apparatus demonstrated to be reliable when measuring ankle torque. When a custom-made dynamometer was used for capturing ankle torque, accuracy of the method was assured by a rigorous calibration and measurement protocol elaboration.

PROPULSION SYSTEM WITH PNEUMATIC ARTIFICIAL MUSCLES FOR POWERING ANKLE-FOOT ORTHOSIS

2013 ◽  
Vol 43 (4) ◽  
pp. 3-16 ◽  
Author(s):  
Ivanka Veneva ◽  
Bram Vanderborght ◽  
Dirk Lefeber ◽  
Pierre Cherelle
Keyword(s):  
Ankle Joint ◽  
Position Control ◽  
Human Motion ◽  
Propulsion System ◽  
Joint Torque ◽  
Joint Control ◽  
Artificial Muscles ◽  
Ankle Foot Orthosis ◽  
Pneumatic Artificial Muscles ◽  
Foot Orthosis

Abstract The aim of this paper is to present the design of device for control of new propulsion system with pneumatic artificial muscles. The propulsion system can be used for ankle joint articulation, for assisting and rehabilitation in cases of injured ankle-foot complex, stroke patients or elderly with functional weakness. Proposed device for control is composed by microcontroller, generator for muscles contractions and sensor system. The microcontroller receives the control signals from sensors and modulates ankle joint flex- ion and extension during human motion. The local joint control with a PID (Proportional-Integral Derivative) position feedback directly calculates desired pressure levels and dictates the necessary contractions. The main goal is to achieve an adaptation of the system and provide the necessary joint torque using position control with feedback.

Nonlinear Modeling of Human Quiet Standing

2012 ◽  
Vol 523-524 ◽  
pp. 717-721
Author(s):  
Hiroyuki Takagi ◽  
Takuya Tabata ◽  
Ken Sasaki
Keyword(s):  
Nonlinear Control ◽  
Ankle Joint ◽  
Center Of Pressure ◽  
Control Model ◽  
Joint Torque ◽  
Quiet Standing ◽  
Upper Body ◽  
Joint Control ◽  
Maximum Deviation ◽  
Evaluation Indexes

Fluctuation during quiet standing of a person is one of the evaluation indexes of aging. Usually, fluctuation is measured by the center of the subject’s weight distribution on the floor, which is called center-of-pressure (COP), or the two dimensional trajectory of the top of the head taken from above the subject. In both cases, common evaluation indexes are standard deviation or maximum deviation. Control models of human quiet standing have been proposed and studied, and now it is widely accepted that human quiet standing is a nonlinear control system. However, there is no established nonlinear control model that expresses the characteristics of human quiet standing accurately. If we could express the nonlinear control dynamics of human quiet standing, the parameters of the control model can be utilized to evaluate subject’s motor control ability in more detail. In this study, we modeled the human body as a two link inverted pendulum. Leaning angle of the lower body and the upper body, and COP were measured in the experiment. Analysis of the data has revealed an asymmetry in the ankle joint torque in the anterior-posterior postural control. This asymmetry was modeled by asymmetric feedback gains of the feedback loop of ankle joint control. The proposed nonlinear model was verified by comparing the simulation results and the experimental data.

Rotational Stiffness of Football Shoes Influences Talus Motion during External Rotation of the Foot

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Feng Wei ◽  
Eric G. Meyer ◽  
Jerrod E. Braman ◽  
John W. Powell ◽  
Roger C. Haut
Keyword(s):  
Ankle Joint ◽  
Joint Torque ◽  
Ankle Injuries ◽  
Design Parameters ◽  
Deltoid Ligament ◽  
Rotational Stiffness ◽  
Shoe Design ◽  
Tibiofibular Ligament ◽  
Ankle Ligament ◽  
Ligament Strain

Shoe-surface interface characteristics have been implicated in the high incidence of ankle injuries suffered by athletes. Yet, the differences in rotational stiffness among shoes may also influence injury risk. It was hypothesized that shoes with different rotational stiffness will generate different patterns of ankle ligament strain. Four football shoe designs were tested and compared in terms of rotational stiffness. Twelve (six pairs) male cadaveric lower extremity limbs were externally rotated 30 deg using two selected football shoe designs, i.e., a flexible shoe and a rigid shoe. Motion capture was performed to track the movement of the talus with a reflective marker array screwed into the bone. A computational ankle model was utilized to input talus motions for the estimation of ankle ligament strains. At 30 deg of rotation, the rigid shoe generated higher ankle joint torque at 46.2 ± 9.3 Nm than the flexible shoe at 35.4 ± 5.7 Nm. While talus rotation was greater in the rigid shoe (15.9 ± 1.6 deg versus 12.1 ± 1.0 deg), the flexible shoe generated more talus eversion (5.6 ± 1.5 deg versus 1.2± 0.8 deg). While these talus motions resulted in the same level of anterior deltoid ligament strain (approxiamtely 5%) between shoes, there was a significant increase of anterior tibiofibular ligament strain (4.5± 0.4% versus 2.3 ± 0.3%) for the flexible versus more rigid shoe design. The flexible shoe may provide less restraint to the subtalar and transverse tarsal joints, resulting in more eversion but less axial rotation of the talus during foot/shoe rotation. The increase of strain in the anterior tibiofibular ligament may have been largely due to the increased level of talus eversion documented for the flexible shoe. There may be a direct correlation of ankle joint torque with axial talus rotation, and an inverse relationship between torque and talus eversion. The study may provide some insight into relationships between shoe design and ankle ligament strain patterns. In future studies, these data may be useful in characterizing shoe design parameters and balancing potential ankle injury risks with player performance.

Estimation of Ankle Joint Torque and Angle Based on S-EMG Signal for Assistive Rehabilitation Robots

2019 ◽  
pp. 31-47 ◽  
Author(s):  
Palayil Baby Jephil ◽  
Paras Acharaya ◽  
Lian Xu ◽  
Kairui Guo ◽  
Hairong Yu ◽  
...  
Keyword(s):  
Ankle Joint ◽  
Joint Torque ◽  
Rehabilitation Robots ◽  
Emg Signal

Efficient dynamic bipedal walking using effects of semicircular feet

Robotica ◽  
2010 ◽  
Vol 29 (3) ◽  
pp. 351-365 ◽  
Author(s):  
Fumihiko Asano ◽  
Zhi-Wei Luo
Keyword(s):  
Ankle Joint ◽  
High Speed ◽  
Joint Torque ◽  
Bipedal Walking ◽  
Convex Curve ◽  
Driving Mechanism ◽  
Dynamic Walking ◽  
Passive Dynamic Walking ◽  
Biped Robots ◽  
Flat Feet

SUMMARYAchieving energy-efficient and high-speed dynamic walking has become one of the main subjects of research in the area of robotic biped locomotion, and passive dynamic walking has attracted a great deal of attention as a solution to this. It is empirically known that the convex curve of the foot, which characterizes passive–dynamic walkers, has an important effect on increasing the walking speed.This paper mainly discusses our investigations into the driving mechanism for compass-like biped robots and the rolling effect of semicircular feet. We first analyze the mechanism for a planar fully actuated compass-like biped model to clarify the importance of ankle-joint torque by introducing a generalized virtual-gravity concept. A planar underactuated biped model with semicircular feet is then introduced and we demonstrate that virtual passive dynamic walking only by hip-joint torque can be accomplished based on the rolling effect. We then compare the rolling effect with a flat feet model through linear approximation, and show that the rolling effect is equivalent to virtual ankle-joint torque. Throughout this paper, we provide novel insights into how zero-moment-point-free robots can generate a dynamic bipedal gait.

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