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Joint Forces (joint + force)
Selected AbstractsFormulation of dynamics, actuation, and inversion of a three-dimensional two-link rigid body systemJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 10 2005Hooshang Hemami In this paper, three issues related to three-dimensional multilink rigid body systems are considered: dynamics, actuation, and inversion. Based on the Newton-Euler equations, a state space formulation of the dynamics is discussed that renders itself to inclusion of actuators, and allows systematic ways of stabilization and construction of inverse systems. The development here is relevant to robotic systems, biological modeling, humanoid studies, and collaborating man-machine systems. The recursive dynamic formulation involves a method for sequential measurement and estimation of joint forces and couples for an open chain system. The sequence can start from top downwards or from the ground upwards. Three-dimensional actuators that produce couples at the joints are included in the dynamics. Inverse methods that allow estimation of these couples from the kinematic trajectories and physical parameters of the system are developed. The formulation and derivations are carried out for a two-link system. Digital computer simulations of a two-rigid body system are presented to demonstrate the feasibility and effectiveness of the methods. © 2005 Wiley Periodicals, Inc. [source] Small unilateral jaw gap variations: equilibrium changes, co-contractions and joint forcesJOURNAL OF ORAL REHABILITATION, Issue 10 2009H. J. SCHINDLER Summary, After complex prosthetic reconstructions, small differences in vertical distances between the left and right side of the jaw may occur during jaw closing, nevertheless providing bilateral tooth contacts in intercuspation by small deformations of the mandible. Their effects on the co-contraction of the masticatory muscles, the temporomandibular joint reaction forces, and the point of application of the resultant bite force vector in the maxillary occlusion plane , the so-called reduction point , have not been investigated, thus far simultaneously in one sample. The main goal of this study was to investigate variations of these measures in an experimental intercuspation simulated by one anterior and two posterior force transmission points. [source] Knee pain in the ACL-deficient osteoarthritic knee and its relationship to quality of lifePHYSIOTHERAPY RESEARCH INTERNATIONAL, Issue 2 2003Michael Hartwick Abstract Background and Purpose Pain during activities of daily living is a common presenting complaint of individuals with knee osteoarthritis and anterior cruciate ligament injury. Knee pain is also associated with a decrease in quality of life for people with osteoarthritis. The purpose of the present study was to examine the dose,response relationship between knee joint forces and painful symptoms, and whether the acute symptoms, were associated with individuals' quality of life. Method This was a cross-sectional cohort correlation study. Seventeen individuals with anterior cruciate ligament (ACL)-deficient knees diagnosed with ipsilateral knee osteoarthritis completed the ACL quality of life questionnaire (ACL-QOL). The subjects also rated pain associated with each of five incremental isometric knee extension tests, proportional to their body weight. Analysis of variance was used to assess the association between pain and normalized torque. Linear regression was used to assess the correlation between the ACL-QOL score and the total pain experienced during the graded test. Results A strong relationship was found between the level of perceived knee pain and the amount of isometric torque produced (Pearson's r = 0.98; p<0.001). There was a statistically significant relationship between pain during the graded isometric test and the ACL-QOL (Pearson's r = ,0.56; p = 0.016). Conclusions Since knee joint compression is a function of active isometric knee extension torque, increased painful symptoms were associated with increased compression forces at the knee joint for these subjects. The relationship between pain provocation and disease-specific quality of life provides evidence for the proposed joint provocation test for this subject population. Weakness caused by osteoarthritis (OA) may, in part, be a negative conditioning response that would need to be overcome in rehabilitation. Copyright © 2003 Whurr Publishers Ltd. [source] Joint And Muscle Forces During ClenchingPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2006Stefan Rues The masticatory system is highly redundant. Therefore, complete knowledge about the activation patterns of the chewing muscles belonging to a specific resultant bite force can only be gained either by simultaneous force- and EMG-measurement or with the help of optimization strategies. In this study, such EMG and force measurements were carried out with 10 test persons and the results compared to those computed with several objective functions. The results show an increase of the joint forces with an increase of the horizontal component of the resultant bite force. The test persons seem to favor energy minimization as control mechanism. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||