Don't Forget the Cyber! Why the Joint Force Commander Must Integrate Cyber Operations Across Other War Fighting Domains, and How a Joint Forces Cyberspace Component Commander Will Help

2009 ◽  
Author(s):  
Martin Stallone
Keyword(s):  
Joint Force ◽  
Joint Forces

Dynamic Motion Analysis of Plane Mechanisms With Coulomb and Viscous Damping via the Joint Force Analysis

1975 ◽  
Vol 97 (2) ◽  
pp. 551-560 ◽  
Author(s):  
Cemil Bagci
Keyword(s):  
Dynamic Equilibrium ◽  
Viscous Damping ◽  
Force Analysis ◽  
Initial Value ◽  
Damping Force ◽  
Joint Force ◽  
Coulomb Damping ◽  
Dynamic Motion ◽  
Joint Forces ◽  
Input Torque

Analysis of response of determinate plane mechanisms to known driving input force, or input torque, via the joint force analysis is presented. Coulomb damping and viscous damping forces in the pair bearings are included. Equations of dynamic equilibrium are solved for the components of the normal joint forces and for the motion of the mechanism as initial-value problems. The rotation of the resultant joint force, due to the fact that the pair member on a link is the inner member or the outer member of the pair, is considered by defining a generalized Coulomb damping force. Links of the mechanisms are considered rigid. The plane 4R and slider-crank switch mechanisms are investigated. Explicit solutions and numerical examples are given.

A Measure for Evaluation of Maximum Acceleration of Redundant and Nonredundant Parallel Manipulators

2015 ◽  
Vol 8 (2) ◽  
Author(s):  
Jun Wu ◽  
Binbin Zhang ◽  
Liping Wang
Keyword(s):  
Dynamic Model ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Virtual Work ◽  
Parallel Manipulators ◽  
Maximum Acceleration ◽  
Virtual Work Principle ◽  
Joint Force ◽  
Joint Forces ◽  
Three Degrees Of Freedom

The paper deals with the evaluation of acceleration of redundant and nonredundant parallel manipulators. The dynamic model of three degrees-of-freedom (3DOF) parallel manipulator is derived by using the virtual work principle. Based on the dynamic model, a measure is proposed for the acceleration evaluation of the redundant parallel manipulator and its nonredundant counterpart. The measure is designed on the basis of the maximum acceleration of the mobile platform when one actuated joint force is unit and other actuated joint forces are less than or equal to a unit force. The measure for evaluation of acceleration can be used to evaluate the acceleration of both redundant parallel manipulators and nonredundant parallel manipulators. Furthermore, the acceleration of the 4-PSS-PU parallel manipulator and its nonredundant counterpart are compared.

scholarly journals Effects of Gait Speed of Femoroacetabular Joint Forces

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Joshua T. Weinhandl ◽  
Bobbie S. Irmischer ◽  
Zachary A. Sievert
Keyword(s):  
Hip Joint ◽  
Gait Speed ◽  
Gait Cycle ◽  
Musculoskeletal Modeling ◽  
Joint Loading ◽  
Joint Force ◽  
Joint Forces ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Vertical Ground Reaction Forces

Alterations in hip joint loading have been associated with diseases such as arthritis and osteoporosis. Understanding the relationship between gait speed and hip joint loading in healthy hips may illuminate changes in gait mechanics as walking speed deviates from preferred. The purpose of this study was to quantify hip joint loading during the gait cycle and identify differences with varying speed using musculoskeletal modeling. Ten, healthy, physically active individuals performed walking trials at their preferred speed, 10% faster, and 10% slower. Kinematic, kinetic, and electromyographic data were collected and used to estimate hip joint force via a musculoskeletal model. Vertical ground reaction forces, hip joint force planar components, and the resultant hip joint force were compared between speeds. There were significant increases in vertical ground reaction forces and hip joint forces as walking speed increased. Furthermore, the musculoskeletal modeling approach employed yielded hip joint forces that were comparable to previous simulation studies and in vivo measurements and was able to detect changes in hip loading due to small deviations in gait speed. Applying this approach to pathological and aging populations could identify specific areas within the gait cycle where force discrepancies may occur which could help focus management of care.

The Application of Optimization Methods for the Calculation of Joint and Muscle Forces

1983 ◽  
Vol 12 (1) ◽  
pp. 29-33 ◽  
Author(s):  
J C Barbenel
Keyword(s):  
Temporomandibular Joint ◽  
Optimization Methods ◽  
Total Force ◽  
Muscle Action ◽  
Muscle Forces ◽  
Joint Force ◽  
Mandibular Joint ◽  
Joint Forces ◽  
Muscles Of Mastication

An analysis is presented of the force actions at the temporomandibular joint and in the muscles of mastication during biting. The resulting equations cannot be solved in order to determine the muscle and joint forces because the number of unknown quantities exceeds the number of equations. Solutions are obtained which minimize either the total force produced by the muscles of mastication or the force at the temporo-mandibular joint. It is shown that the predictions of muscle action obtained from these solutions are at variance with the muscles shown to be active experimentally. The limitations of the application of optimization procedures to redundant problems associated with muscle and joint force analyses are discussed.

Dynamic Modeling of a Slider-Crank Mechanism Under Joint Wear

2008 ◽  
Author(s):  
Saad Mukras ◽  
Nate Mauntler ◽  
Nam Ho Kim ◽  
Tony Schmitz ◽  
W. Gregory Sawyer
Keyword(s):  
Finite Element ◽  
Dynamic Model ◽  
Dynamic Modeling ◽  
Iterative Scheme ◽  
Wear Depth ◽  
Wear Prediction ◽  
Joint Force ◽  
Joint Forces ◽  
Modeling Techniques ◽  
Crank Mechanism

A study of how joint wear affects the kinematics of a simple slider-crank mechanism and in turn how change in kinematics of the mechanism affects the joint wear is presented. The coupling between joint wear and system kinematics is modeled by integrating a wear prediction process, built upon a widely used finite-element-based iterative scheme, with the dynamic model that has an imperfect joint whose kinematics changes progressively according to joint wear. Three different modeling techniques are presented based on different assumptions, and their performances are compared in terms of joint forces and wear depths. It turns out that the joint wear increases the joint force and accelerates the wear progress. The accuracy of integrated dynamic model is validated by measuring joint force and wear depth of the slider-crank mechanism. Details of instrumentation are also presented.

Force Balancing of Robotic Mechanisms Based on Adjustment of Kinematic Parameters

2004 ◽  
Vol 127 (3) ◽  
pp. 433-440 ◽  
Author(s):  
P. R. Ouyang ◽  
W. J. Zhang
Keyword(s):  
Mechanism Design ◽  
Real Time ◽  
Mass Distribution ◽  
Trajectory Tracking ◽  
Design Equation ◽  
Kinematic Parameters ◽  
Joint Force ◽  
Joint Forces ◽  
Working Principle ◽  
Better Than

Force balancing is a very important issue in mechanism design and has only recently been introduced to the design of robotic mechanisms. In this paper, a force balancing method called adjusting kinematic parameters (AKP) for robotic mechanisms or real-time controllable (RTC) mechanisms is proposed, as opposed to force balancing methods, e.g., the counterweights (CW) method. Both the working principle of the AKP method and the design equation with which to construct a force balanced mechanism are described in detail. A particular implementation of the AKP method for the RTC mechanisms where two pivots on a link are adjustable is presented. A comparison of the two methods, namely the AKP method and the CW method, is made for two RTC mechanisms with different mass distribution. The joint forces and torques are calculated for the trajectory tracking of the RTC mechanisms. The result shows that the AKP method is consistently better than the CW method in terms of the reduction of the joint forces and the torques in the servomotors, and the smoothing of the fluctuation of the joint force.

scholarly journals Determination of Joint Load of Human Lower Limb by Using 2D Inverse Dynamics Modelling

2019 ◽  
Vol 9 (1) ◽  
pp. 5723-5727
Keyword(s):  
Lower Limb ◽  
Inverse Dynamics ◽  
Joint Force ◽  
Joint Forces ◽  
Limb Kinematics ◽  
Dynamics Modelling ◽  
Squat Lifting ◽  
Joint Load ◽  
Joint Loads ◽  
Matlab Programming

The human lower limb is a major part of the human body that is exposed to high joint load during daily activities. Different lifestyles and cultural activities can affect the loading condition generated at the joint during motion. For instance, deep squatting is more frequently performed by Asians compared to Europeans e.g. kneeing on tatami among Japanese and sitting position during prayer among Muslims. The aim of this research is to determine the joint load of the human lower limb during the squat lifting movement by using inverse dynamics of 2-dimensional (2D) human lower limb model. The 2D inverse dynamics modelling was used to describe and compute all the joint force reactions from the known ground reaction and lower limb kinematics. In this study, 2D human lower limb model was analysed during the squat lifting movement. Inverse dynamics computation was performed using MATLAB programming based on Newton-Euler equations to determine the joint forces and moments. The joint loads at ankle, knee and hip joints for every knee flexion angle were obtained and the maximum forces at the ankle, knee and hip were 613.9, 614.1 and 596.1 N, respectively.

scholarly journals Muscle Activation and Estimated Relative Joint Force During Running with Weight Support on a Lower-Body Positive-Pressure Treadmill

2016 ◽  
Vol 32 (4) ◽  
pp. 335-341 ◽  
Author(s):  
Bente R. Jensen ◽  
Line Hovgaard-Hansen ◽  
Katrine L. Cappelen
Keyword(s):  
Ankle Joint ◽  
Muscle Activation ◽  
Positive Pressure ◽  
Lower Body ◽  
Joint Force ◽  
Lower Body Positive Pressure ◽  
Weight Support ◽  
Joint Forces ◽  
Body Positive ◽  
Leg Muscle

Running on a lower-body positive-pressure (LBPP) treadmill allows effects of weight support on leg muscle activation to be assessed systematically, and has the potential to facilitate rehabilitation and prevent overloading. The aim was to study the effect of running with weight support on leg muscle activation and to estimate relative knee and ankle joint forces. Runners performed 6-min running sessions at 2.22 m/s and 3.33 m/s, at 100%, 80%, 60%, 40%, and 20% body weight (BW). Surface electromyography, ground reaction force, and running characteristics were measured. Relative knee and ankle joint forces were estimated. Leg muscles responded differently to unweighting during running, reflecting different relative contribution to propulsion and antigravity forces. At 20% BW, knee extensor EMGpeak decreased to 22% at 2.22 m/s and 28% at 3.33 m/s of 100% BW values. Plantar flexors decreased to 52% and 58% at 20% BW, while activity of biceps femoris muscle remained unchanged. Unweighting with LBPP reduced estimated joint force significantly although less than proportional to the degree of weight support (ankle).It was concluded that leg muscle activation adapted to the new biomechanical environment, and the effect of unweighting on estimated knee force was more pronounced than on ankle force.

Physical Modelling of Hip Joint Forces in Stair Climbing

1996 ◽  
Vol 210 (1) ◽  
pp. 65-68 ◽  
Author(s):  
F J Shelley ◽  
D D Anderson ◽  
M J Kolar ◽  
M C Miller ◽  
H E Rubash
Keyword(s):  
Hip Joint ◽  
Femoral Shaft ◽  
Physical Modelling ◽  
Stair Climbing ◽  
Flexion Angle ◽  
Joint Force ◽  
Joint Forces ◽  
Flexion Moment ◽  
Hip Flexion ◽  
Femoral Flexion

A test device has been developed and validated to simulate physiologic loading of the hip during stair climbing. Forces about the hip joint were measured in static simulations of stair climbing using simulated extensor, abductor and adductor muscle groups to support the joint. Femoral flexion angle (to model step length and height) and applied hip flexion moment (to model trunk lean) were varied to examine the effects of different loading conditions on the hip. In stair climbing the maximum total joint force was six times body weight at 34° of femoral flexion and 60 N m of hip flexion moment. Joint forces increased with hip flexion moment and varied little with femoral flexion angle, except for the posteriorly directed force. This component, which twists implants about the femoral shaft, increased with femoral flexion angle but changed little with hip flexion moment.

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