scholarly journals BASIC APPROACHES AND USED METHODS IN THE TREATMENT OF COMBINED (LONGITUDINAL-TRANSVERSE) PLATFOOT

2021 ◽  
Vol 10 (4) ◽  
pp. 72-77
Author(s):  
E. E. Achkasov ◽  
V. A. Frolov ◽  
V. V. Berezin
Keyword(s):  
Musculoskeletal System ◽  
Degrees Of Freedom ◽  
Experimental Studies ◽  
Kinematic Chain ◽  
Treatment Methods ◽  
Single Mechanism ◽  
Effective Combination ◽  
Flat Feet ◽  
Domestic Practice ◽  
Basic Approaches

The article reflects the consideration of the problem of treatment of combined (longitudinal-transverse) flat feet and the use of various methods of correction of this pathology. The main approaches to the treatment of combined (longitudinal-transverse) flat feet are considered and a brief review of experimental studies and patent developments in relation to the treatment of combined (longitudinal-transverse) flat feet. The analysis of the experience of using various treatment methods for combined (longitudinal-transverse) flat feet in foreign and domestic practice is presented, problematic aspects of the fight against the pathology under consideration are highlighted. It is noted that the separate use of various treatment methods for combined (longitudinal-transverse) flatfoot has insufficient effectiveness and is associated with the risk of re-development of pathology, while the greatest effect in the early stages of the development of combined flatfoot gives the use of complex treatment, using both medication and various orthopedic methods, exercise therapy, and massage. The need for further scientific research in relation to the most effective combination of different treatment methods for combined flat feet was determined, which would give a positive dynamics of changes both in relation to the feet and lower extremities in general, and in relation to the entire musculoskeletal system. The necessity of considering the musculoskeletal system and the feet as a single mechanism, a kinematic chain with degrees of freedom (mobility and deformability in the joint), in which the transfer of reactive or reflected forces in the linking chain of the chain

scholarly journals Influence of lower leg myofascial kinematic chains on flat feet development of children 7-14 years old

2019 ◽  
Vol 5 (2) ◽  
pp. 28 ◽  
Author(s):  
A. Danyschuk
Keyword(s):  
Experimental Studies ◽  
Kinematic Chain ◽  
Motor Units ◽  
Biomechanical Properties ◽  
Flat Foot ◽  
Kinematic Chains ◽  
Flat Feet ◽  
The Relationship ◽  
Possible Cause ◽  
Anthropometric Study

<p><strong>The aim of the work </strong>is to study the biomechanical properties of the myo-fascial kinematic chain "foot-shin" of children of 7-14 years old with non-fixed and clinically expressed flat-footedness.</p><p><strong>Material and methods</strong>. The study involved 14 children with flat-footedness of grades I-II and 6 children with flat-foot deformity of the foot and 20 children who only had functional disorders of the foot. An anthropometric study of the foot was carried out, electrophysiological indicators of the muscles of the leg were determined, and plantograms were analyzed.</p><p><strong>Results</strong>. The study found a correlation between the indicators of the anatomical and functional state of the foot and the imbalance of the frequency-amplitude indices of the ipsi and contralateral muscles within one link of the myofacial kinematic chain, may be important as one of the factors that contribute to the development of flatfoot. This is confirmed by other indicators and indicate a decrease in the height of the longitudinal arch, a decrease in the metatarsal and heel angles of the arch of the foot. Such changes have a pronounced relationship with age. The results of the work indicate that a possible cause of flattening of the vaulted apparatus of the foot is not only the weakness of its joint-ligament-muscular system, but also above the located kinematic segment - the tibia. The correlation analysis revealed the relationship between the indicators of the development of the anatomical and biomechanical components of the foot and the characteristics of the electromyographic indicators of the muscles of the leg in children 7-14 years old. As a result of a comprehensive study, it was found that during this period of ontogenesis in the formation of flatfoot such electromyographic indicators as frequency-amplitude characteristics of action potentials of motor units of the long and posterior tibial muscles, as well as their tone imbalance, take on major importance.</p><p><strong>Conclutions</strong>. Experimental studies have established that the registered changes in the articular components of the foot of children 7-14 years old lead to a change in the electromyographic parameters of the muscles of the leg, which are involved in the formation of the initial sections of myo-fascial kinematic chains.</p>

Functional and Constructive Optimization of a Serial-Modular Industrial Robot Implemented within a Single Purpose Flexible Manufacturing Cell

2012 ◽  
Vol 186 ◽  
pp. 239-246
Author(s):  
Silviu Mihai Petrişor ◽  
Ghiţă Bârsan
Keyword(s):  
Flexible Manufacturing ◽  
Degrees Of Freedom ◽  
Industrial Robot ◽  
Kinematic Chain ◽  
Chain Structure ◽  
Calculation Algorithm ◽  
Flexible Manufacturing Cell ◽  
Manufacturing Cell ◽  
Lagrangian Equations ◽  
Selection Of

The authors of this paper aim to highlight the basic design of a flexible manufacturing cell destined for the final processing of water radiators used for AAVs, cell serviced by a serial modular industrial robot possessing in its kinematic chain structure three degrees of freedom, RRT SIL type. The paper outlines the concept, calculation and design of the (MRB) rotation module at the studied industrial robot’s base and of the (MT) translation module of the prehension device attached to the robotic arm. Depending on the organological elements that are part of the MRB rotation module and based on a rigorous dynamic study performed on robotic modules, modeling conducted with the help of Lagrangian equations of the second kind, a dynamic-organological calculation algorithm was obtained for the selection of the appropriate driving servomotor necessary to putting the rotation movable system into service. The last part of the paper deals with the flexible manufacturing cell, together with the calculations related to profitability, economy and investment return duration, following the implementation of the RRT SIL-type industrial robot.

scholarly journals Model Calibration for a Rigid Hexapod-Based End-Effector with Integrated Force Sensors

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3537
Author(s):  
Christian Friedrich ◽  
Steffen Ihlenfeldt
Keyword(s):  
Parameter Identification ◽  
Degrees Of Freedom ◽  
Force Measurement ◽  
Experimental Studies ◽  
Measurement Model ◽  
Calibration Procedure ◽  
Force Sensors ◽  
End Effector ◽  
Measurement Models ◽  
Fast Procedure

Integrated single-axis force sensors allow an accurate and cost-efficient force measurement in 6 degrees of freedom for hexapod structures and kinematics. Depending on the sensor placement, the measurement is affected by internal forces that need to be compensated for by a measurement model. Since the parameters of the model can change during machine usage, a fast and easy calibration procedure is requested. This work studies parameter identification procedures for force measurement models on the example of a rigid hexapod-based end-effector. First, measurement and identification models are presented and parameter sensitivities are analysed. Next, two excitation strategies are applied and discussed: identification from quasi-static poses and identification from accelerated continuous trajectories. Both poses and trajectories are optimized by different criteria and evaluated in comparison. Finally, the procedures are validated by experimental studies with reference payloads. In conclusion, both strategies allow accurate parameter identification within a fast procedure in an operational machine state.

Balancing Control of a Mobile Manipulator with Two Wheels by an Acceleration-Based Disturbance Observer

2018 ◽  
Vol 15 (03) ◽  
pp. 1850005 ◽  
Author(s):  
Yeong-Geol Bae ◽  
Seul Jung
Keyword(s):  
Disturbance Observer ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Experimental Studies ◽  
Service Robot ◽  
Mobile Manipulator ◽  
Control Performance ◽  
Six Degrees Of Freedom ◽  
Inertia Model ◽  
Balancing Control

This paper presents the balancing control performance of a mobile manipulator built in the laboratory as a service robot called Korean robot worker (KOBOKER). The robot is designed and implemented with two wheels as a mobile base and two arms with six degrees-of-freedom each. Kinematics and dynamics of the robot are analyzed. For the balancing control performance, two wheels are controlled independently by the time-delayed control method based on the inertia model of the robot. The acceleration information obtained directly from the sensor is used for the modified disturbance observer structure called an acceleration-based disturbance observer (AbDOB). Experimental studies of the balancing control of the robot are conducted to compare the control performances by both a PID control method and an AbDOB.

Concise Review of Classical Guitar Modelling Technologies

2021 ◽  
Vol 11 (1) ◽  
pp. 25
Author(s):  
Alexandre M. Löw ◽  
Herbert M. Gomes ◽  
César M. A. Vasques
Keyword(s):  
Degrees Of Freedom ◽  
Research Area ◽  
Coupled Systems ◽  
Mode Shapes ◽  
Classical Guitar ◽  
Concise Review ◽  
Lumped Parameter ◽  
Basic Approaches ◽  
Shed Light

Analytical modeling and numerical simulation of multiphysics coupled systems is an exciting research area, even when it comes to intrinsically linear or linearized formulations, as is usually the case with coupled vibroacoustic problems. The combined effect of many localized geometrical miss-modeling with significant uncertainty in mechanical characterization of some organic materials yields large discrepancies in the natural frequencies and mode shapes obtained. The main goal of this work is to compare two basic approaches for the modeling of stringed musical instruments in the frequency domain: simplified lumped-parameter analytic modeling, considering only the most influential degrees of freedom, and discretized finite element modal analysis. Thus, the emphasis is on a review of some key references in this field, including previous work by the authors, which may shed light on some of the most relevant issues surrounding this problem.

scholarly journals 3DOF Ultrasonic Motor with Two Piezoelectric Rings

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 834 ◽  
Author(s):  
Vytautas Jūrėnas ◽  
Gražvydas Kazokaitis ◽  
Dalius Mažeika
Keyword(s):  
Numerical Simulation ◽  
Magnetic Dipole ◽  
Attitude Control ◽  
Degrees Of Freedom ◽  
High Reliability ◽  
Experimental Studies ◽  
Main Idea ◽  
Ultrasonic Motor ◽  
Response Analysis ◽  
Magnetic Sphere

A novel design of a multiple degrees of freedom (multi-DOF) piezoelectric ultrasonic motor (USM) is presented in the paper. The main idea of the motor design is to combine the magnetic sphere type rotor and two oppositely placed ring-shaped piezoelectric actuators into one mechanism. Such a structure increases impact force and allows rotation of the sphere with higher torque. The main purpose of USM development was to design a motor for attitude control systems used in small satellites. A permanent magnetic sphere with a magnetic dipole is used for orientation and positioning when the sphere is rotated to the desired position and the magnetic field synchronizes with the Earth’s magnetic dipole. Also, the proposed motor can be installed and used for robotic systems, laser beam manipulation, etc. The system has a minimal number of components, small weight, and high reliability. Numerical simulation and experimental studies were used to verify the operating principles of the USM. Numerical simulation of a piezoelectric actuator was used to perform modal frequency and harmonic response analysis. Experimental studies were performed to measure both mechanical and electrical characteristics of the piezoelectric motor.

PSEUDO PROBABILISTIC APPROACH TO TEST ISOMORPHISM AMONG KINEMATIC CHAINS

1997 ◽  
Vol 21 (2) ◽  
pp. 65-83 ◽  
Author(s):  
S. Shubhashis ◽  
M. Choubey ◽  
A.C. Rao
Keyword(s):  
Numerical Scheme ◽  
Degrees Of Freedom ◽  
Probabilistic Approach ◽  
Kinematic Chain ◽  
Single Degree Of Freedom ◽  
Reliable Test ◽  
Kinematic Chains ◽  
Single Degree ◽  
Unique Method ◽  
P Matrix

There is no dearth of methods to test isomorphism amongst kinematic chains. Search for a computationally easier, logically simple and unique method is still on. Present work is in quest of a reliable test to detect isomorphism among kinematic chains. Work presented here is more versatile as it incorporates more features of the kinematic chain which were not included earlier such as number and type of links, their relative dispositions in the kinematic chain, nature of adjacent links etc. The method proposed is based on the concept of pseudo-probability (pseudo means it appears to be, but not exactly. The approach does not follow in-toto the principles of probability and considerable liberty has been taken in interpreting the word probability hence the word pseudo is used along with the probability schemes). Using the resemblance of different coloured balls in an urn for the number and type of links in a kinematic chain, a matrix (named P-Matrix) representing the kinematic chain in totality is generated. For the sake of comparison a numerical scheme named, pseudo probability scheme, P-Scheme, is developed from the above P-Matrix and is used for testing isomorphism. In fact the method is more powerful in the sense that each row of the proposed P-Matrix is capable of representing the respective kinematic chain distinctly and can be used to compare the kinematic chains with same link assortments, uniquely. The proposed method, besides possessing the potential of testing the isomorphism among simple-joint, single degree of freedom kinematic chains is also capable of multi degrees of freedom and multiple-joint kinematic chains.

Kinematic and Dynamic Analysis of a Two-Degree-of-Freedom Spherical Wrist

2010 ◽  
Vol 2 (3) ◽  
Author(s):  
M. Ruggiu
Keyword(s):  
Condition Number ◽  
Performance Index ◽  
Degrees Of Freedom ◽  
Kinematic Chain ◽  
Scanning System ◽  
Spherical Wrist ◽  
Moving Platform ◽  
Two Degree Of Freedom ◽  
Spherical Motion ◽  
Motion Generator

The present paper proposes the analysis of a spherical wrist with two degrees of freedom for scanning system applications. The wrist consists of two chains of revolute-revolute pairs. A slotted arc connecting the two chains behaves as a further revolute pair. Thus, the mechanism is an overconstrained (meaning of this definition is discussed in this work) single-loop kinematic chain composed of five revolute pairs equivalent to a spherical motion generator since all its axes intersect at a point. Throughout the paper, the kinematic analysis is developed including some details about the workspace, which depends on the design of the slotted arc. The performance index given as the inverse of the condition number is used to measure the performances of the motion of the moving platform of the wrist. The singularity poses found were examined in detail. A simplified dynamic model is proposed that provides the torques suitable for satisfying a given kinematics. Finally, the paper presents a motorized hardware model of the mechanism assembled in the laboratory.

Jacobian Derivation of 5-DOF 3R2T Parallel Mechanisms

2004 ◽  
Author(s):  
Qinchuan Li ◽  
Xudong Hu ◽  
Zhen Huang
Keyword(s):  
Degrees Of Freedom ◽  
Jacobian Matrix ◽  
Screw Theory ◽  
Kinematic Chain ◽  
Parallel Mechanisms ◽  
Mobility Analysis

This paper presents a method for the Jacobian derivation of 5-DOF 3R2T PMs (parallel mechanisms), where 3R denotes three rotational DOFs (degrees of freedom) and 2T denotes two translational DOFs. First the mobility analysis of such kind of parallel mechanisms is reviewed briefly. The Jacobian matrix of the single limb kinematic chain is obtained via screw theory, which is a 6 × 5 matrix. Then it is shown that the mobility analysis of such kind of PM is important when simplifying the 6 × 5 matrix into a 5 × 5 Jacobian matrix. After obtaining the 5 × 5 Jacobian matrix for each limb, a 5 × 5 Jacobian matrix for the whole mechanism can be established.

Prediction of the Behavior of Dynamically Actuated DE Roll-Actuators Using Equivalent Circuits

2020 ◽  
Author(s):  
Petko Bakardjiev ◽  
Uwe Marschner ◽  
Markus Franke ◽  
Andreas Richter ◽  
Ercan M. Altinsoy
Keyword(s):  
Degrees Of Freedom ◽  
Model Updating ◽  
Experimental Studies ◽  
Axial Direction ◽  
Dielectric Elastomer ◽  
Design Parameters ◽  
Interface Circuits ◽  
Efficient Manner ◽  
Dielectric Elastomer Actuators ◽  
Conventional Systems

Abstract Dielectric elastomer actuators show suitable properties to be utilized for dynamic applications, e.g. speakers, shakers and pumps, with possible benefits to existing conventional systems. In this work a method to predict the performance of dynamically actuated dielectric-elastomer roll-actuators (DERA) depending on both, material and design parameters is presented. It incorporates in combination analytical computation, FEM, as well as electromechanical networks and considers a large variety of material configurations with a multitude of constructional degrees of freedom. DERA in push-configuration exhibit a distinct modal behavior in axial direction depending on the boundary conditions and loading at the actuators end terminals, which is described sufficiently by a one-dimensional longitudinal waveguide model. Several DERA were designed, manufactured and tested. The experimental studies were in good agreement with the made predictions. They allowed for further refinement regarding interface circuits and model updating, such as the estimation of inaccessible parameters (e. g. damping coefficients). The presented model allows for extensive parameter studies and the development of tailor-made actuators for given application in a very time efficient manner.

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