scholarly journals Simulation Evaluation for Methods Used to Determine Muscular Internal Force Based on Joint Stiffness Using Muscular Internal Force Feedforward Controller for Musculoskeletal System

2021 ◽  
Vol 8 ◽  
Author(s):  
Yuki Matsutani ◽  
Kenji Tahara ◽  
Hitoshi Kino
Keyword(s):  
Musculoskeletal System ◽  
Joint Stiffness ◽  
Internal Force ◽  
Control Performance ◽  
Arbitrary Vector ◽  
Simulation Evaluation ◽  
Ill Posed ◽  
Feedforward Controller ◽  
Low Stiffness ◽  
Definition Of

This study proposes two novel methods for determining the muscular internal force (MIF) based on joint stiffness, using an MIF feedforward controller for the musculoskeletal system. The controller was developed in a previous study, where we found that it could be applied to achieve any desired end-point position without the use of sensors, by providing the MIF as a feedforward input to individual muscles. However, achieving motion with good response and low stiffness using the system, posed a challenge. Furthermore, the controller was subject to an ill-posed problem, where the input could not be uniquely determined. We propose two methods to improve the control performance of this controller. The first method involves determining a MIF that can independently control the response and stiffness at a desired position, and the second method involves the definition of an arbitrary vector that describes the stiffnesses at the initial and desired positions to uniquely determine the MIF balance at each position. The numerical simulation results reported in this study demonstrate the effectiveness of both proposed methods.

scholarly journals Off-Shell Noether Currents and Potentials for First-Order General Relativity

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 348
Author(s):  
Merced Montesinos ◽  
Diego Gonzalez ◽  
Rodrigo Romero ◽  
Mariano Celada
Keyword(s):  
General Relativity ◽  
Vector Fields ◽  
Killing Vector ◽  
Spherically Symmetric ◽  
Killing Vector Fields ◽  
Arbitrary Vector ◽  
Four Dimensions ◽  
First Order ◽  
Direct Form ◽  
Definition Of

We report off-shell Noether currents obtained from off-shell Noether potentials for first-order general relativity described by n-dimensional Palatini and Holst Lagrangians including the cosmological constant. These off-shell currents and potentials are achieved by using the corresponding Lagrangian and the off-shell Noether identities satisfied by diffeomorphisms generated by arbitrary vector fields, local SO(n) or SO(n−1,1) transformations, ‘improved diffeomorphisms’, and the ‘generalization of local translations’ of the orthonormal frame and the connection. A remarkable aspect of our approach is that we do not use Noether’s theorem in its direct form. By construction, the currents are off-shell conserved and lead naturally to the definition of off-shell Noether charges. We also study what we call the ‘half off-shell’ case for both Palatini and Holst Lagrangians. In particular, we find that the resulting diffeomorphism and local SO(3,1) or SO(4) off-shell Noether currents and potentials for the Holst Lagrangian generically depend on the Immirzi parameter, which holds even in the ‘half off-shell’ and on-shell cases. We also study Killing vector fields in the ‘half off-shell’ and on-shell cases. The current theoretical framework is illustrated for the ‘half off-shell’ case in static spherically symmetric and Friedmann–Lemaitre–Robertson–Walker spacetimes in four dimensions.

The equivalence of a jointed shield-driven tunnel lining to a continuous ring structure

2001 ◽  
Vol 38 (3) ◽  
pp. 461-483 ◽  
Author(s):  
K M Lee ◽  
X W Ge
Keyword(s):  
Pressure Distribution ◽  
Joint Stiffness ◽  
Earth Pressure ◽  
Horizontal Displacement ◽  
Internal Force ◽  
Ring Structure ◽  
Tunnel Lining ◽  
Bending Rigidity ◽  
Continuous Ring ◽  
Soft Clays

This paper presents a new method of determining the correction factor to approximate a jointed, shield-driven tunnel lining as a continuous ring structure under plane strain conditions. An earth pressure distribution pattern is proposed which is developed based on the long-term behavior of shallow tunnels constructed in soft clays as observed in the field. The "force method" was used to determine the internal forces and displacements of jointed, shield-driven tunnels. Either the vertical or the horizontal displacement of the tunnel lining can be used as a common matching parameter. Factors such as joint stiffness, soil resistance, joint distribution, number of joints, and tunnel geometry can be considered by the proposed method. Simplified design equations for the estimation of equivalence factors are also proposed for the typical tunnel lining geometry of urban subway tunnels. The proposed equivalence method was evaluated by comparing it with the results of laboratory tests.Key words: shield-driven tunnel, jointed segmental lining, effective bending rigidity ratio, equivalence factor, lining internal force, earth pressure distribution.

scholarly journals Muscular internal force determination method using reinforcement learning for feedforward positioning of musculoskeletal system

2015 ◽  
Vol 81 (822) ◽  
pp. 14-00313-14-00313
Author(s):  
Yuki MATSUTANI ◽  
Kenji TAHARA ◽  
Hitoshi KINO ◽  
Hiroaki OCHI ◽  
Motoji YAMAMOTO
Keyword(s):  
Reinforcement Learning ◽  
Musculoskeletal System ◽  
Internal Force ◽  
Determination Method

scholarly journals THERAPEUTIC OPPORTUNITIES OF CARBOXYTHERAPY IN ORTHOPEDICS

2020 ◽  
pp. 21-26
Author(s):  
C. M. Drogovoz ◽  
L. B. Ivantsyk ◽  
Yu. V. Stoletov ◽  
A. L. Shtroblya
Keyword(s):  
Side Effects ◽  
Musculoskeletal System ◽  
Muscle Relaxation ◽  
Joint Stiffness ◽  
Trigger Points ◽  
Inflammatory Conditions ◽  
Symptom Complex ◽  
Post Traumatic ◽  
Inflammatory Drugs ◽  
Anti Inflammatory

Diseases of the musculoskeletal system are quite common diseases. Moreover, the use of pharmacotherapy may not always be effective, which is associated with a large number of side effects of modern non-steroidal anti-inflammatory drugs (NSAIDs). The way out of the situation can be the use of carboxytherapy (CO2 therapy), which has a complex of pharmacological effects: analgesic, anti-inflammatory, antispasmodic, antihypoxic and antioxidant.These CO2 effects are used to eliminate the symptom complex associated with pain, inflammation, ischemia, hypoxia, and joint stiffness. The use of carboxytherapy in orthopedics is primarily aimed at eliminating pain in various diseases of the spine, joints, muscles in the back, neck, thighs, knees and other organs. The main target of the action of carboxytherapy in diseases of the musculoskeletal system are Zakharyin – Geda zones, trigger points, myofibralgia zones and acupuncture points.When CO2 affects these zones and points, vasodilation, muscle relaxation and increased tissue oxygenation reflexively occur, which leads to a decrease in inflammation, pain and other functional disorders in the joints and muscles. Due to the polypathopathogenetic pharmacodynamics of CO2, carboxytherapy is often used for post-traumatic and inflammatory conditions of joints, arthrosis, and other acute and chronic joint pathologies of various etiologies.In addition, with combined pharmacotherapy of these diseases, carboxytherapy reduces the duration of NSAIDs and other drugs, reduces their dosage, which reduces the risk of side effects and increases the effectiveness of CO2 therapy.

scholarly journals Development of a closed-loop fes system using a 3-d magnetic position and orientation measurement system

2002 ◽  
Vol 12 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Kenji Kurosawa ◽  
Takashi Watanabe ◽  
Ryoko Futami ◽  
Nozomu Hoshimiya ◽  
Yasunobu Handa
Keyword(s):  
Musculoskeletal System ◽  
Measurement System ◽  
Degrees Of Freedom ◽  
Closed Loop ◽  
Experimental System ◽  
Control Performance ◽  
Orientation Measurement ◽  
Position And Orientation ◽  
Position And Orientation Measurement ◽  
Freedom Movement

We have developed a closed-loop FES system using a magnetic 3-D position and orientation measurement system (FASTRAK, Polhemus Inc). The purpose of this development was to resolve some experimental difficulties involved in our previous goniometer-based experimental system. The new system enabled us to perform FES control experiments on the multi-joint musculoskeletal system of the upper limbs including forearm pronation/supination. In this paper, we evaluated the system by some single-joint tracking tasks in order to compare its control performance with that of the previous system. Four muscles (ECRL(B), ECU, FCR, and FCU) of neurologically intact subjects were stimulated to control the wrist joint's two degrees of freedom movement. Stimulation currents were determined by a multi-channel PID controller that was designed for a musculoskeletal system with redundancy (i.e. the number of muscles stimulated is more than that of the degree-of-freedom of the movement). The results showed that the system had sufficient control performance on tracking desired trajectories. Moreover, the system could compensate for unwanted external disturbances.

scholarly journals A Quantum Chemistry Approach to the Force Fields of the Thionyl and Selenyl Halides, SOX2 and SeOX2

2007 ◽  
Vol 62 (12) ◽  
pp. 1491-1496
Author(s):  
Lis E. Fernández ◽  
Eduardo L. Varetti
Keyword(s):  
Experimental Data ◽  
Quantum Mechanics ◽  
Quantum Chemistry ◽  
Force Fields ◽  
Internal Force ◽  
Vibrational Frequencies ◽  
Force Constants ◽  
Definition Of ◽  
Theoretical Results

Force fields and vibrational frequencies were calculated for the molecules SOX2 and SeOX2, with X = F, Cl, Br, using DFT techniques. The previously available experimental data and assignments for the six molecules were confirmed by the theoretical results. These data were subsequently used in the definition of the corresponding scaled quantum mechanics (SQM) force fields. A comparison of the obtained internal force constants is made with results reported by other authors for the studied species.

A Stabilization Method of F-barES-FEM-T4 for Dynamic Explicit Analysis of Nearly Incompressible Materials

2019 ◽  
Vol 16 (08) ◽  
pp. 1850121 ◽  
Author(s):  
Ryoya Iida ◽  
Yuki Onishi ◽  
Kenji Amaya
Keyword(s):  
Internal Force ◽  
Stabilization Method ◽  
Tetrahedral Elements ◽  
Incompressible Materials ◽  
Explicit Analysis ◽  
Smoothed Finite Element Method ◽  
Edge Based ◽  
Definition Of ◽  
Force Calculation ◽  
Better Than

A stabilization method of the F-bar aided edge-based smoothed finite element method with four-node tetrahedral elements (F-barES-FEM-T4), which is named SymF-barES-FEM-T4, is proposed. The proposed formulation aims to remove the instability associated with energy divergence of F-barES-FEM-T4 in dynamic analysis. The stiffness matrix of F-barES-FEM-T4 is asymmetric due to the adoption of F-bar method, meanwhile that of SymF-barES-FEM-T4 is symmetrized so that the dynamics system of the formulation is stabilized. The differences between F-barES-FEM-T4 and SymF-barES-FEM-T4 in their formulations are only the definition of the [Formula: see text]-matrix and the corresponding volume in the internal force calculation. Therefore, SymF-barES-FEM-T4 is applicable in dynamic explicit schemes as is the case with F-barES-FEM-T4. A few demonstrations of dynamic explicit analysis for nearly incompressible materials reveal that SymF-barES-FEM-T4 conserves the total energy and does not cause energy divergence in the free vibration problems. They also reveal that SymF-barES-FEM-T4 has a moderate capability in the suppression of pressure checkerboarding: worse than F-barES-FEM-T4 but better than Selective ES/NS-FEM-T4.

The Simplified Calculation of the End Moments for Steel Frames with Semi-Rigid Connections

2011 ◽  
Vol 105-107 ◽  
pp. 1712-1716
Author(s):  
Zhang Qi Hu ◽  
Wei Rong Lv ◽  
Yuan Li ◽  
Chao Fei Wang
Keyword(s):  
Steel Structures ◽  
Internal Force ◽  
Structure Design ◽  
Steel Frame ◽  
Frame Design ◽  
Traditional Design ◽  
Internal Forces ◽  
Column Joint ◽  
Definition Of ◽  
Simplified Calculation

In the structure design, the definition of the joints had a great impact on the structure internal force distribution, thus affecting the whole structure design. In the traditional design of steel structures, the beam-column joints were always considered as completely rigid connections or ideal hinged connections, but it is usually not in accord with the practical situations. According to the existing formulas, the simplified formulas for the end moments of semi-rigid connections have been proposed, the semi-rigid connections will also be discussed. The formulas proposed in this paper are applied to the auxiliary beam-column joint design, which is part of the counterforce frame design. It is hoped that the formulas can provide a reference for the steel frame design. Keywords: semi-rigid connections, end moments, internal forces distribution, steel frame design

APPLICABILITY OF FUZZY LOGIC TO THE DEFINITION OF THE BUCKLING LENGTH OF STEEL PLANE FRAMES

2009 ◽  
Vol 1 (3) ◽  
pp. 135-140
Author(s):  
Zdeněk Kala ◽  
Abayomi Omishore ◽  
Libor Puklický
Keyword(s):  
Fuzzy Logic ◽  
Input Data ◽  
Joint Stiffness ◽  
Order Theory ◽  
Extension Principle ◽  
Shape Functions ◽  
Plane Frames ◽  
Modelling Uncertainties ◽  
Definition Of ◽  
Buckling Length

This paper presents a fuzzy-logic-based approach to the definition of buckling length evoked by the uncertainty of joint stiffness and boundary conditions for the member support. The example demonstrates a lucid and specific application of fuzzy sets in modelling uncertainties in design. To carry out analysis, the extension principle in the form of α-cuts was used. Buckling lengths were analysed utilizing stability solution according to the second-order theory. The beam finite element method with the shape functions of sin and sinh was utilized in the analysis taking into account valuable information on the uncertainties of input data.

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