scholarly journals A Kinematic Model of a Humanoid Lower Limb Exoskeleton with Hydraulic Actuators

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6116
Author(s):  
Sebastian Glowinski ◽  
Tomasz Krzyzynski ◽  
Aleksandra Bryndal ◽  
Igor Maciejewski
Keyword(s):  
Mathematical Model ◽  
Lower Limb ◽  
Geometric Model ◽  
Kinematic Model ◽  
Lower Limb Exoskeleton ◽  
Angle Data ◽  
Proposed Model ◽  
Characteristic Points ◽  
Measurement Units ◽  
Matlab Package

Although it is well-established that exoskeletons as robots attached to the extremities of the human body increase their strength, limited studies presented a computer and mathematical model of a human leg hydraulic exoskeleton based on anthropometric data. This study aimed to examine lower limb joint angles during walking and running by using Inertial Measurement Units. The geometry and kinematic parameters were calculated. Twenty-six healthy adults participated in walking and running experiments. The geometric model of a human leg hydraulic exoskeleton was presented. Joint angle data acquired during experiments were used in the mathematical model. The position and velocity of exoskeleton actuators in each phase of movement were calculated using the MATLAB package (Matlab_R2017b, The MathWorks Company, Novi, MI, USA). The highest velocity of the knee actuator during walking and running was in the swing phase, 0.3 and 0.4 m/s, respectively. For the ankle and hip joints, the highest velocity of actuators occurred during the push-off phase. The results with 26 healthy subjects demonstrated that the system's compliance can be effectively adjusted while guiding the subjects walking in predefined trajectories. The developed mathematical model makes it possible to determine the position of lower limb segments and exoskeleton elements. The proposed model allows for calculating the position of the human leg and actuators’ characteristic points.

Design and validation of a lower limb exoskeleton employing the recumbent cycling modality for post-stroke rehabilitation

2014 ◽  
Vol 228 (18) ◽  
pp. 3517-3525 ◽  
Author(s):  
Hua Yan ◽  
Canjun Yang
Keyword(s):  
Lower Limb ◽  
Muscle Power ◽  
Sagittal Plane ◽  
Kinematic Model ◽  
Stroke Patients ◽  
Post Stroke ◽  
Lower Limb Exoskeleton ◽  
Exoskeleton Robot ◽  
Limited Range Of Motion ◽  
Custom Made

This paper presents the design and validation of a lower limb exoskeleton robot for post-stroke patients at the early stage of neurorehabilitation. Instead of the usual walking gait, the popular exercise, recumbent cycling, is adopted to provide a safe and comfortable movement training to the patients who lost active motor abilities due to a very low muscle power. The exoskeleton robot mounted on a commercial wheelchair possesses two pairs of hip and knee joints on the right and left legs, respectively, and each joint has one degree of freedom actuated by a custom-made linear actuator in the sagittal plane. Additionally, two passive ankle joints are added to provide a limited range of motion for human comfort. The hip and knee joint motion profiles were calculated based on a simplified kinematic model of the recumbent cycling modality, and implemented through the motor position–velocity–time trajectory. Clinical trials were conducted on six stable post-stroke patients with a low muscle power under the supervision of a skilled therapist. The preliminary results validated the functionality and feasibility of the new exoskeleton robot and showed a promising application of the recumbent cycling modality in robot-assisted neurorehabilitation.

scholarly journals ALICE: Conceptual Development of a Lower Limb Exoskeleton Robot Driven by an On-Board Musculoskeletal Simulator

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 789 ◽  
Author(s):  
Manuel Cardona ◽  
Cecilia E. García Cena ◽  
Fernando Serrano ◽  
Roque Saltaren
Keyword(s):  
Lower Limb ◽  
Conceptual Development ◽  
Human Gait ◽  
Lower Limb Exoskeleton ◽  
Gait Parameters ◽  
Measurement Units ◽  
Mechanical Sensor ◽  
Wearable Exoskeleton ◽  
Novel Concept ◽  
Real Time Information

Objective: In this article, we present the conceptual development of a robotics platform, called ALICE (Assistive Lower Limb Controlled Exoskeleton), for kinetic and kinematic gait characterization. The ALICE platform includes a robotics wearable exoskeleton and an on-board muscle driven simulator to estimate the user’s kinetic parameters. Background: Even when the kinematics patterns of the human gait are well studied and reported in the literature, there exists a considerable intra-subject variability in the kinetics of the movements. ALICE aims to be an advanced mechanical sensor that allows us to compute real-time information of both kinetic and kinematic data, opening up a new personalized rehabilitation concept. Methodology: We developed a full muscle driven simulator in an open source environment and validated it with real gait data obtained from patients diagnosed with multiple sclerosis. After that, we designed, modeled, and controlled a 6 DoF lower limb exoskeleton with inertial measurement units and a position/velocity sensor in each actuator. Significance: This novel concept aims to become a tool for improving the diagnosis of pathological gait and to design personalized robotics rehabilitation therapies. Conclusion: ALICE is the first robotics platform automatically adapted to the kinetic and kinematic gait parameters of each patient.

APPLICATION OF HOMOGENOUS TRANSFORMATION MATRIX TO THE MODELING OF A BALL-END CUTTER

2013 ◽  
Vol 37 (3) ◽  
pp. 775-785
Author(s):  
Jung-Fa Hsieh
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Geometric Model ◽  
Straightforward Method ◽  
Proposed Model ◽  
Cnc Grinding ◽  
Wide Range ◽  
Grinding Machine ◽  
Cnc Grinding Machine ◽  
Flank Surface

This paper presents a comprehensive and straightforward method for the mathematical modeling of a generic ball-end cutter. In the proposed approach, a mathematical model of the rake surface is developed based on a normal helix cutting edge geometric model. A mathematical model of the flank surface is then derived based on the assumption of a constant clearance angle. The proposed model is applicable to a wide range of ball-end cutters. As a result, it provides an ideal basis for the generation of the NC equations required to machine ball-end cutters on a 6-axis CNC grinding machine.

Powering a Lower Limb Exoskeleton Using Pneumatic Artificial Muscles

2016 ◽  
Author(s):  
Jonathan M. Chambers ◽  
Craig R. Carignan ◽  
Norman M. Wereley
Keyword(s):  
Knee Joint ◽  
Lower Limb ◽  
Kinematic Model ◽  
Knee Joints ◽  
Transmission Model ◽  
Artificial Muscles ◽  
Lower Limb Exoskeleton ◽  
Actuation System ◽  
Pneumatic Artificial Muscles ◽  
Assembly Tasks

Passive leg exoskeletons are currently being investigated for offsetting the weight of tools and other loads from workers performing maintenance and assembly tasks. By providing power-assist to the knee joints with pneumatic artificial muscles (PAMs), a wider range of stances could be used by maintenance workers without drawing significant power. A simplified kinematic model of the exoskeleton is developed, and the array of potential user stance configurations is then bounded. A static analysis is performed to define the torque required for actuation of the knee joint to support the tool loads carried by the exoskeleton. Finally, an exemplary transmission model is used to verify that it is feasible for a PAM to provide the range of motion and forces required for knee joint actuation. Upon demonstration of the viability of PAM actuation, development of an exoskeleton leg prototype is underway to provide validation of the proposed scheme. The knee actuation system will be retrofit to the FORTIS exoskeleton, and tests on its effectiveness will be conducted.

THE DEVELOPMENT OF THE MATHEMATICAL MODEL OF PREDICTING THE INDICATORS OF ACCREDITATION OF TECHNICAL UNIVERSITIES IN THE RUSSIAN FEDERATION

2017 ◽  
pp. 27-38
Author(s):  
Olga Mikhaylovna Tikhonova ◽  
Alexander Fedorovich Rezchikov ◽  
Vladimir Andreevich Ivashchenko ◽  
Vadim Alekseevich Kushnikov
Keyword(s):  
Mathematical Model ◽  
System Dynamics ◽  
Regression Model ◽  
Oriented Graph ◽  
Real Data ◽  
Educational Process ◽  
Proposed Model ◽  
Linear Differential ◽  
The University ◽  
The Mathematical Model

The paper presents the system of predicting the indicators of accreditation of technical universities based on J. Forrester mechanism of system dynamics. According to analysis of cause-and-effect relationships between selected variables of the system (indicators of accreditation of the university) there was built the oriented graph. The complex of mathematical models developed to control the quality of training engineers in Russian higher educational institutions is based on this graph. The article presents an algorithm for constructing a model using one of the simulated variables as an example. The model is a system of non-linear differential equations, the modelling characteristics of the educational process being determined according to the solution of this system. The proposed algorithm for calculating these indicators is based on the system dynamics model and the regression model. The mathematical model is constructed on the basis of the model of system dynamics, which is further tested for compliance with real data using the regression model. The regression model is built on the available statistical data accumulated during the period of the university's work. The proposed approach is aimed at solving complex problems of managing the educational process in universities. The structure of the proposed model repeats the structure of cause-effect relationships in the system, and also provides the person responsible for managing quality control with the ability to quickly and adequately assess the performance of the system.

Analyzing Motor Primitives of Healthy Subjects Wearing a Lower Limb Exoskeleton

2017 ◽  
Author(s):  
Wilian dos Santos ◽  
Samuel Lourenco ◽  
Adriano Siqueira ◽  
Polyana Ferreira Nunes
Keyword(s):  
Lower Limb ◽  
Healthy Subjects ◽  
Motor Primitives ◽  
Lower Limb Exoskeleton

A Mathematical Model for the Anaerobic Digestion Process Applied to a Mixture of Night Soil and Septic Tank Sludge

1986 ◽  
Vol 18 (7-8) ◽  
pp. 239-248 ◽  
Author(s):  
Sung Ryong Ha ◽  
Dwang Ho Lee ◽  
Sang Eun Lee
Keyword(s):  
Mathematical Model ◽  
Anaerobic Digestion ◽  
Biomass Concentration ◽  
Gas Production ◽  
Septic Tank ◽  
Volatile Acid ◽  
Hydraulic Residence Time ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Proposed Model

Laboratory scale experiments were conducted to develop a mathematical model for the anaerobic digestion of a mixture of night soil and septic tank sludge. The optimum mixing ratio by volume between night soil and septic tank sludge was found to be 7:3. Due to the high solids content in the influent waste, mixed-liquor volatile suspended solids (MLVSS) was not considered to be a proper parameter for biomass concentration, therefore, the active biomass concentration was estimated based on deoxyribonucleic acid (DNA) concentration in the reactor. The weight ratio between acidogenic bacteria and methanogenic bacteria in the mixed culture of a well-operated anaerobic digester was approximately 3:2. The proposed model indicates that the amount of volatile acid produced and the gas production rate can be expressed as a function of hydraulic residence time (HRT). The kinetic constants of the two phases of the anaerobic digestion process were determined, and a computer was used to simulate results using the proposed model for the various operating parameters, such as BOD5 and volatile acid concentrations in effluent, biomass concentrations and gas production rates. These were consistent with the experimental data.

scholarly journals On the Dragging Trajectory of Anchors in Clay for Merchant Ships

2021 ◽  
Vol 9 (2) ◽  
pp. 118
Author(s):  
Xinqing Zhuang ◽  
Keliang Yan ◽  
Pan Gao ◽  
Yihua Liu
Keyword(s):  
Mathematical Model ◽  
Structural Integrity ◽  
Indirect Measurement ◽  
Test System ◽  
Flow Rule ◽  
Burial Depth ◽  
Proposed Model ◽  
Depth Increase ◽  
Two Parameters ◽  
The Mathematical Model

Anchor dragging is a major threat to the structural integrity of submarine pipelines. A mathematical model in which the mechanical model of chain and the bearing model of anchor were coupled together. Based on the associated flow rule, an incremental procedure was proposed to solve the spatial state of anchor until it reaches the ultimate embedding depth. With an indirect measurement method for the anchor trajectory, a model test system was established. The mathematical model was validated against some model tests, and the effects of two parameters were studied. It was found that both the ultimate embedding depth of a dragging anchor and the distance it takes to reach the ultimate depth increase with the shank-fluke pivot angle, but decrease as the undrained shear strength of clay increases. The proposed model is supposed to be useful for the embedding depth calculation and guiding the design of the pipeline burial depth.

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