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Journal articles on the topic 'Joint forces'
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1
Harl, Boštjan. "Probabilistic behaviour of joints on joint forces in mechanisms." Tehnicki vjesnik - Technical Gazette 22, no. 1 (2015): 113–17. http://dx.doi.org/10.17559/tv-20131023220214.
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Zhou, Dongbo, Kotaro Tadano, and Daisuke Haraguchi. "Motion Control and External Force Estimation of a Pneumatically Driven Multi-DOF Robotic Forceps." Applied Sciences 10, no. 11 (May 26, 2020): 3679. http://dx.doi.org/10.3390/app10113679.
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Robotic forceps with a rigid-link joint mechanism is orthodox for current robotic-assisted surgery systems. However, external force estimation without force sensors during operations is difficult for such electrically driven forceps. This work introduces a pneumatically driven multi-DOF (DOF: degree of freedom) forceps using a rigid-link mechanism with less interference of the wire drive between joints and realizes external force estimation by utilizing high back-drivability of pneumatic cylinders. We developed a position controller with dynamic compensation of the mechanical friction, in which the rotational angles of the three movable joints of the forceps are independently controlled. Moreover, we designed an external force observer in the position controller by applying the disturbance observer scheme. The results of the performance evaluation experiments are as follows. First, in the joint position control experiments, smooth and stable controllability is confirmed for sinusoidal reference inputs with the mean absolute errors of less than 2°. The resolution of the joint position control is approximately 1° for the response of step increasing reference inputs, which is acceptable for laparoscopic surgery. Second, the external force observer can correctly estimate the translational and the grasping forces with less than 20% errors of the maximum output forces. The practical sensitivities of the external force estimation are better than 0.5 N for translational forces and 0.2 N for grasping forces. The achieved performance of the developed forceps can be applicable for interactive force control in some particular surgical tasks such as suturing, ligation, organ traction and exclusion.
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Schreck, Michael J., Meghan Kelly, Colin D. Canham, and John C. Elfar. "Techniques of Force and Pressure Measurement in the Small Joints of the Wrist." HAND 13, no. 1 (February 6, 2017): 23–32. http://dx.doi.org/10.1177/1558944716688529.
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Background: The alteration of forces across joints can result in instability and subsequent disability. Previous methods of force measurements such as pressure-sensitive films, load cells, and pressure-sensing transducers have been utilized to estimate biomechanical forces across joints and more recent studies have utilized a nondestructive method that allows for assessment of joint forces under ligamentous restraints. Methods: A comprehensive review of the literature was performed to explore the numerous biomechanical methods utilized to estimate intra-articular forces. Results: Methods of biomechanical force measurements in joints are reviewed. Conclusions: Methods such as pressure-sensitive films, load cells, and pressure-sensing transducers require significant intra-articular disruption and thus may result in inaccurate measurements, especially in small joints such as those within the wrist and hand. Non-destructive methods of joint force measurements either utilizing distraction-based joint reaction force methods or finite element analysis may offer a more accurate assessment; however, given their recent inception, further studies are needed to improve and validate their use.
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Christian ; Anastasia Maurina, Kenny. "EVALUASI SAMBUNGAN MUR-BAUT STRUKTUR PORTAL TRUSS “THE GREAT HALL” OBI ECO CAMPUS - JATILUHUR." Riset Arsitektur (RISA) 2, no. 03 (July 5, 2018): 317–34. http://dx.doi.org/10.26593/risa.v2i03.2949.317-334.
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Abstract- Bolt joint is one of the common joineries in a modern bamboo construction. The usage of the bolt joints in bamboo joinery are believed to be the most efficient therefore the bolt joint was used regardless of the various kind of different forces in every bamboo joinery. One of the disadvantage of the bolt joints in bamboo construction in the force that flow parallel to the bamboo fibers therefore some of joineries needed to be strengthen to prevent the joinery failure. The Great Hall OBI Eco Campus is one of the building which the joineries entirely connected by the bolt joints, through different forces in every joinery some of the joinery in the building are strengthen by rope. The bolt joints have many other combinations to strengthen the joinery that could be an option, they are bolt joint with clamping and with mortar injection. Key Words: Bolt Joint, parallel forcee to the bamboo fiber, strengthen by rope, “The Great Hall” OBI Eco Campus, Clamping, Mortar Injection
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Witte, Hartmut, Jutta Biltzinger, Rémi Hackert, Nadja Schilling, Manuela Schmidt, Christian Reich, and Martin S. Fischer. "Torque patterns of the limbs of small therian mammals during locomotion on flat ground." Journal of Experimental Biology 205, no. 9 (May 1, 2002): 1339–53. http://dx.doi.org/10.1242/jeb.205.9.1339.
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SUMMARY In three species of small therian mammals (Scandentia: Tupaia glis, Rodentia: Galea musteloides and Lagomorpha: Ochotona rufescens) the net joint forces and torques acting during stance phase in the four kinematically relevant joints of the forelimbs (scapular pivot,shoulder joint, elbow joint, wrist joint) and the hindlimbs (hip joint, knee joint, ankle joint, intratarsal joint) were determined by inverse dynamic analysis. Kinematics were measured by cineradiography (150 frames s-1). Synchronously ground reaction forces were acquired by forceplates. Morphometry of the extremities was performed by a scanning method using structured illumination. The vector sum of ground reaction forces and weight accounts for most of the joint force vector. Inertial effects can be neglected since errors of net joint forces amount at most to 10 %. The general time course of joint torques is comparable for all species in all joints of the forelimb and in the ankle joint. Torques in the intratarsal joints differ between tailed and tail-less species. The torque patterns in the knee and hip joint are unique to each species. For the first time torque patterns are described completely for the forelimb including the scapula as the dominant propulsive segment. The results are compared with the few torque data available for various joints of cats(Felis catus), dogs (Canis lupus f. familiaris),goats (Capra sp.) and horses (Equus przewalskii f. caballus).
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Chen, Chao, Huiyang Zhang, Hao Peng, Xiangkun Ran, and Qing Pan. "Investigation of the Restored Joint for Aluminum Alloy." Metals 10, no. 1 (January 7, 2020): 97. http://dx.doi.org/10.3390/met10010097.
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In recent years, the mechanical clinching method plays an increasingly important role in the building of thin-walled structures. The clinched joint can be employed to join the lightweight materials. Compared with other joining methods, the clinched joint has better mechanical behavior. However, the clinched joint may be deformed during use when it bears a high shear force. In this research, a process to join aluminum alloy and restore deformed joint was proposed and investigated. The clinched joint was deformed in the deforming process. Then, a customized rivet and two flat restoring tools were utilized for restoring the deformed joint to join aluminum alloy. Different restoring forces such as 45, 40, 35, 30, 25, and 20 kN were employed to produce diverse restored joints. Some shearing tests on the restored joint were utilized for understanding joint material flow, mode of failure, thickness of neck, shear strength, and absorption of energy. The thickness of neck can be increased in restoring process, which contributes to improve the shear strength. The rivet embedded in a pit also helps restored joint bear shear force, so all of the restored joints have higher absorption of energy and shear strength than the clinched joints. The restoring process effectively restores the deformed joint to obtain better mechanical behavior.
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Breloff, Scott P., and Li-Shan Chou. "THREE-DIMENSIONAL MULTI-SEGMENTED SPINE JOINT REACTION FORCES DURING COMMON WORKPLACE PHYSICAL DEMANDS/ACTIVITIES OF DAILY LIVING." Biomedical Engineering: Applications, Basis and Communications 29, no. 04 (August 2017): 1750025. http://dx.doi.org/10.4015/s1016237217500259.
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Objective: The quantification of inter-segmental spine joint reaction forces during common workplace physical demands. Background: Many spine reaction force models have focused on the L5/S1 or L4/L5 joints to quantify the vertebral joint reaction forces. However, the L5/S1 or L4/L5 approach neglects most of the intervertebral joints. Methods: The current study presents a clinically applicable and noninvasive model which calculates the spinal joint reaction forces at six different regions of the spine. Subjects completed four ambulatory activities of daily living: level walking, obstacle crossing, stair ascent, and stair descent. Results: Peak joint spinal reaction forces were compared between tasks and spine regions. Differences existed in the bodyweight normalized vertical joint reaction forces where the walking (8.05[Formula: see text][Formula: see text][Formula: see text]3.19[Formula: see text]N/kg) task had significantly smaller peak reaction forces than the stair descent (12.12[Formula: see text][Formula: see text][Formula: see text]1.32[Formula: see text]N/kg) agreeing with lower extremity data comparing walking and stair descent tasks. Conclusion: This method appears to be effective in estimating the joint reaction forces using a segmental spine model. The results suggesting the main effect of peak reactions forces in the segmental spine can be influenced by task.
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Mason, J. J., F. Leszko, T. Johnson, and R. D. Komistek. "Patellofemoral joint forces." Journal of Biomechanics 41, no. 11 (August 2008): 2337–48. http://dx.doi.org/10.1016/j.jbiomech.2008.04.039.
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Schindler, H. J., S. Rues, J. C. Türp, K. Schweizerhof, and J. Lenz. "Jaw Clenching: Muscle and Joint Forces, Optimization Strategies." Journal of Dental Research 86, no. 9 (September 2007): 843–47. http://dx.doi.org/10.1177/154405910708600907.
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Realistic masticatory muscle and temporomandibular joint forces generated during bilateral jaw clenching are largely unknown. To determine which clenching directions load masticatory muscles and temporomandibular joints most heavily, we investigated muscle and joint forces based on feedback-controlled electromyograms of all jaw muscles, lines of action, geometrical data from the skull, and physiological cross-sectional areas acquired from the same individuals. To identify possible motor control strategies, we applied objective functions. The medial pterygoid turned out to be the most heavily loaded muscle for all bite directions. Biting with accentuated horizontal force components provoked the highest loading within the medial and lateral pterygoids. The largest joint forces were also found for these bite directions. Conversely, the lowest joint forces were detected during vertical biting. Additionally, joint forces with a clear posterior orientation were found. Optimization strategies with the elastic energy as objective function revealed the best fit with the calculated results.
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Usherwood, James R., and Michael C. Granatosky. "Limb work and joint work minimization reveal an energetic benefit to the elbows-back, knees-forward limb design in parasagittal quadrupeds." Proceedings of the Royal Society B: Biological Sciences 287, no. 1940 (December 9, 2020): 20201517. http://dx.doi.org/10.1098/rspb.2020.1517.
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Quadrupedal animal locomotion is energetically costly. We explore two forms of mechanical work that may be relevant in imposing these physiological demands. Limb work, due to the forces and velocities between the stance foot and the centre of mass, could theoretically be zero given vertical limb forces and horizontal centre of mass path. To prevent pitching, skewed vertical force profiles would then be required, with forelimb forces high in late stance and hindlimb forces high in early stance. By contrast, joint work—the positive mechanical work performed by the limb joints—would be reduced with forces directed through the hip or shoulder joints. Measured quadruped kinetics show features consistent with compromised reduction of both forms of work, suggesting some degree of, but not perfect, inter-joint energy transfer. The elbows-back, knees-forward design reduces the joint work demand of a low limb-work, skewed, vertical force profile. This geometry allows periods of high force to be supported when the distal segment is near vertical, imposing low moments about the elbow or knee, while the shoulder or hip avoids high joint power despite high moments because the proximal segment barely rotates—translation over this period is due to rotation of the distal segment.
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Dien, Nguyen Phong, and Nguyen Van Khang. "Dynamic force analysis of a six-link planar mechanism under consideration of friction at the joints." Vietnam Journal of Mechanics 26, no. 2 (July 1, 2004): 65–75. http://dx.doi.org/10.15625/0866-7136/26/2/5690.
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The dynamic analysis of mechanisms with joints friction is complex since the frictional force depends nonlinearly on the resultant reactive force between the two mating surfaces of the joint. In this paper a non-iterative approximate method is used for determining the joint reaction forces and the driving torque of mechanisms is considered. By using the computing program MATLAB the dynamic forces of a six-link planar mechanism are calculated with this method.
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Drapała, Krzysztof, Kazimierz Pulaski, and Wojciech Blajer. "THE INFLUENCE OF ACTUATION MODELING ON THE ASSESSED JOINT REACTIONS IN BIOMECHANICAL SYSTEMS." Polish Journal of Sport and Tourism 20, no. 3 (September 1, 2013): 183–87. http://dx.doi.org/10.2478/pjst-2013-0016.
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Abstract Introduction. Human body biomechanical models are actuated either by net torques at the joints or individual muscle forces whose action around the joints results, by principle, in the net torques. In the model-based inverse dynamics simulation of human movements the assessed joint reactions depend substantially on the choice of the actuation model, which is discussed in the paper. Material and methods. Using the two actuation models, variant biomechanical models of the lower limb, decomposed from the whole human body, were developed. They were then used for the inverse dynamics simulation of a recorded one-leg jump on the force platform to assess time variations of controls (either net torques or muscle forces) and joint reactions. Results. The assessed joint reactions obtained using the model actuated by net torques are substantially different from those obtained by means of the model actuated by muscle forces. Conclusion. The joint reactions computed using the model actuated by net torques do not involve contribution of the tensile muscle forces to the internal loads, and they are therefore underestimated. Determination of joint reactions should thus be based on musculoskeletal models actuated by the muscle forces.
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Aizawa, Koki, Daisuke Haraguchi, and Kotaro Tadano. "Load Reduction Control on Tool-Insertion Port for Laparoscopic Surgical Robot Using Semi-Active Joints." Journal of Robotics and Mechatronics 32, no. 5 (October 20, 2020): 1000–1009. http://dx.doi.org/10.20965/jrm.2020.p1000.
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In robotic surgery, the load exerted on the insertion port in the patient’s abdominal wall due to misalignment of the robot’s remote center of motion and the insertion port or external forces acting on the tip of the forceps during surgery, can not only stress the patient’s body but also increase the friction between the robotic forceps and the trocar, and adversely affect fine surgical manipulations or the accuracy of force estimation. To reduce such loads on the insertion port in robotic surgery, this study proposes a control method for a surgical assist robotic arm with semi-active joints. The control method was implemented on a six-degree-of-freedom pneumatically driven vertical multi-joint robotic arm with a two-axis gimbal joint (two semi-active joints) that only executes torque control, which was previously developed by the authors, and verified through an experiment. The load on the insertion port is reduced by applying torque control on the semi-active joints to compensate for the external forces on the forceps. We constructed a control system that includes a disturbance compensator and conducted a velocity-control experiment by subjecting the forceps constrained by the insertion port to an external force. The results showed that when the torque was compensated for by the semi-active joints, the load on the insertion port was reduced by 65% and 52% when the external force on the tip of the forceps was 0 N and 3 N, respectively.
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Seo, Min Jwa, and Hyeon Ki Choi. "Joint Reaction Forces during the Recovery of Postural Balance of Human Body." Key Engineering Materials 297-300 (November 2005): 2308–13. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.2308.
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The purpose of this study was to calculate three dimensional angular displacements, moments and joint reaction forces (JRF) of the ankle joint during the waist pulling, and to assess the ankle JRF according to different perturbation modes and different levels of perturbation magnitude. Ankle joint model was assumed 3-D ball and socket joint which is capable of three rotational movements. We used 6 camera motion analysis system, force plate and waist pulling system. Two different waist pulling systems were adopted for forward sway with three magnitudes each. From motion data and ground reaction forces, we could calculate 3-D angular displacements, moments and JRF during the recovery of postural balance control. From the experiment using mass-falling perturbation, joint moments were larger than those from the experiment with milder perturbation using air cylinder pulling system. However, joint reaction forces were similar nevertheless the difference in joint moment. From the results, we could conjecture that the human body employs different strategies to protect joints by decreasing joint reaction forces, like using the joint movements or compensating JRF by distributing the forces on surrounding soft tissues. The results of this study provide us important insights for understanding the relationship between balance control and ankle injury mechanism.
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Feng, B., N. Morita, and T. Torii. "A New Optimization Method for Dynamic Design of Planar Linkage With Clearances at Joints—Optimizing the Mass Distribution of Links to Reduce the Change of Joint Forces." Journal of Mechanical Design 124, no. 1 (May 1, 1999): 68–73. http://dx.doi.org/10.1115/1.1425393.
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This paper presents a new optimization method for dynamic design of planar linkage with clearances at joints. The general consideration is to optimize the mass distribution of links to reduce the change of joint forces. The mass, the center position of mass and the moment of inertia the moving links are taken as the optimizing variables. The objective functions are taken as the changes of the amplitude and direction of the joint forces and they are minimized. The optimized result shows that the magnitude of joint force can be controlled hardly to change and the direction of joint force can be controlled to change smoothly with respect to the crank angle, although the clearances exist at the joints. The link shape can be formed with the optimized variables by using the small element superposing method (SESM) and a design example is given.
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Jurj, Lenard, Radu Saulescu, and Radu Velicu. "Sprocket - Silent Chain Force Distribution with the Influence of Friction." Applied Mechanics and Materials 880 (March 2018): 21–26. http://dx.doi.org/10.4028/www.scientific.net/amm.880.21.
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The aim of this paper is to define and to analyse the theoretical contact forces that appear in a sprocket - silent chain joint. The contact force between the links and the teeth flanks of the sprocket can be considered as a reaction to the axial force in chain (tensioning force), transmitted throughout the pin - links joints. Friction forces will be considered in the joints and in the link - sprocket joints, which will be defined by the corresponding friction angles. The centrifugal force is also considered. This paper is presenting the steps to obtain the analytical model for the forces from the sprocket - link and the pin - link joints, depending on the tensioning force and the centrifugal force. These forces are computed in order to establish their distribution along links.
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Gilman, C. "PASSIVE-AGGRESSIVE JOINT FORCES." Journal of Experimental Biology 216, no. 23 (November 20, 2013): vi. http://dx.doi.org/10.1242/jeb.084533.
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Sanchez-Palencia, Laurent. "Joint forces against disorder." Nature Physics 6, no. 5 (May 2010): 328–29. http://dx.doi.org/10.1038/nphys1662.
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Karduna, A. R., G. R. Williams, J. P. Iannotti, and J. L. Williams. "Total Shoulder Arthroplasty Biomechanics: A Study of the Forces and Strains at the Glenoid Component." Journal of Biomechanical Engineering 120, no. 1 (February 1, 1998): 92–99. http://dx.doi.org/10.1115/1.2834312.
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The objective of this study was to examine how changes in glenohumeral joint conformity and loading patterns affected the forces and strains developed at the glenoid. After removal of soft tissue (muscles, ligaments, and labrum), force-displacement data were collected for both natural and prosthetically reconstructed joints. Joints were shown to develop higher forces for a given translation as joint conformity increased. A rigid body model of joint contact forces was used to determined the so-called effective radial mismatch of each joint. For the purposes of this study, the effective radial mismatch is defined as the mismatch required for a rigid body joint to have the same force-displacement relationship as the joint in question. This parameter is an indication of the deformation at the articular surface. The effective radial mismatch dramatically increased with increasing medial loads, indicating that under physiological loads, the effective radial mismatch of a joint is much greater than its measured mismatch at no load. This increase in effective mismatch as medial loads were increased was found to be threefold greater in cartilaginous joints than in reconstructed joints. Rosette strain gages positioned at the midlevel of the glenoid keel in the reconstructed joints revealed that anterior/posterior component loading leads to fully reversible cyclic keel strains. The highest compressive strains occurred with the head centered in the glenoid, and were larger for nonconforming joints (ε = 0.23 percent). These strains became tensile just before rim loading and were greater for conforming joints (ε = 0.15 percent). Although recorded peak strains are below the yield point for polyethylene, the fully reversed cyclic loading of the component in this fashion may ultimately lead to component toggling and implant failure.
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Liao, Bing, Yong Feng Luo, and Xiao Nong Guo. "Experiment of the SCT Joint under Complicated Loading." Advanced Materials Research 255-260 (May 2011): 607–13. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.607.
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A radial-circle-lined grid shell, its height changed step by step in the radial direction, is adopted in the roof steel structure of the Citizen Water Sports Center in Jiangyin, China. And the Spatial Crossing Tubular (SCT) joint is used for the connection of pipe members. Because the force transmission in the roof structure is different from the traditional truss structure, a lot of SCT joints are in a complicated loading state. The joint forces include axial forces and in/out-of-plane moments. To investigate the mechanical behavior and the load-bearing capacity of a typical SCT joint in such complicated loading condition, a full size model test of the typical SCT joint is conducted. The test process is summarized in the paper, together with the finite element calculation of the typical SCT joint in test conditions. By comparing the numerical results with the test results, several significant parameters of the connection are investigated, including the stiffness change of the joint, the transmission mechanism of forces, the ultimate load-bearing capacity and the failure mode of the joint. After investigation, several useful suggestions are proposed for the SCT joint design. They are also valuable for the design of similar SCT joints under complicated loading condition.
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Wang, Gang, and Zhaohui Qi. "Approximate determination of the joint reaction forces in the drive system with double universal joints." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 232, no. 7 (April 4, 2017): 1191–207. http://dx.doi.org/10.1177/0954406217702681.
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In this study, a drive system connected by rolling bearings and double universal joints is modeled as a closed-loop multibody system. Because of the existence of redundant constraints, the joint reaction forces cannot be determined uniquely through dynamic analysis. Based on the physical mechanism where the joint reaction forces are the resultants of contact forces at the joint definition point, a methodology of frictionless contact analysis is presented to identify joint reaction forces. In terms of D’Alembert’s principle, the dynamic equations of constrained multibody systems are equivalent to the equilibrium equations of all bodies composed of joint contact forces, externally applied forces, and inertial forces. The equivalent equilibrium equations provide a set of complementary equations to identify the contact positions and contact forces in the rolling bearings and double universal joints. The drive system is also simulated using ADAMS software, where all the joints are released and the corresponding constraint functions are replaced by the impact forces between the joint components. Some conclusions are obtained through the comparison of numerical examples between the proposed method and the ADAMS model. In the double universal joints, the equations are adequate and independent, which results in that the corresponding contact positions and contact forces can be solved uniquely. Then, the correlation between the data produced by these two models is acceptable in the engineering practices. Furthermore, contact details in the double universal joints can be obtained without the calculation of the relative motion between the cross-pin and yokes. However, the reaction forces in the rolling bearings are indeterminate due to that their complementary equations are not independent. The proposed method has high efficiency and acceptable precision.
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Colborne, G. R. "Are sound dogs mechanically symmetric at trot?" Veterinary and Comparative Orthopaedics and Traumatology 21, no. 03 (2008): 294–301. http://dx.doi.org/10.1055/s-0037-1617375.
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SummaryA two-year-old, sound Labrador Retriever was determined to be ’right hind limb dominant’ by comparison of total hind limb moments of support using inverse dynamics. Net joint moments at the hip, tarsal and metatarsophalangeal joints were larger on the right side. Vertical joint reaction forces at the stifle were larger on the right, and horizontal stifle joint reaction forces were smaller on the right. The crus segment was more cranially inclined on the right side through most of stance, but the angle of the resultant stifle joint reaction force vector against the long axis of the crus segment was identical between the right and left sides. The cranially inclined crus segment orientation on one side, coupled with the larger vertical joint reaction force, may result in an internal asymmetry in stifle joint mechanics, although the effects of this on cruciate ligament stresses remain to be determined.
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Chen, D. C., A. A. Shabana, and J. Rismantab-Sany. "Generalized Constraint and Joint Reaction Forces in the Inverse Dynamics of Spatial Flexible Mechanical Systems." Journal of Mechanical Design 116, no. 3 (September 1, 1994): 777–84. http://dx.doi.org/10.1115/1.2919450.
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In both the augmented and recursive formulations of the dynamic equations of flexible mechanical systems, the inerita, constraints, and applied forces must be properly defined. The inverse dynamics is a commonly used approach for the force analysis of mechanical systems. In this approach, the system is kinematically driven using specified motion trajectories, and the objective is to determine the driving forces and torques. In flexible body dynamics, however, a force that acts at a point on the deformable body is equipollent to a system, defined at another point, that consists of the same force, a moment that depends on the relative deformation between the two points, and a set of generalized forces associated with the elastic coordinates. Furthermore, a moment in flexible body dynamics is no longer a free vector. It is defined by the location of its line of action as well as its magnitude and direction. The joint reaction and generalized constraint forces represent equipollent systems of forces. Both systems in flexible body dynamics are function of the deformation. In this investigation, a procedure is developed for the determination of the joint reaction forces in spatial flexible mechanical systems. The mathematical formulation of some mechanical joints that are often encountered in the analysis of constrained flexible mechanical systems is discussed. Expressions for the generalized reaction forces in terms of the constraint Jacobian matrices of the joints are presented. The effect of the elastic deformation on the reaction forces is also examined numerically using the spatial flexible multibody RSSR mechanism that consists of a set of interconnected rigid and elastic bodies. The procedure described in this investigation can also be used to determine the joint torques and actuator forces in kinematically driven spatial elastic mechanism and manipulator systems.
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Biscarini, Andrea. "Non-Slender n-Link Chain Driven by Single-Joint and Multi-joint Muscle Actuators: Closed-Form Dynamic Equations and Joint Reaction Forces." Applied Sciences 11, no. 15 (July 26, 2021): 6860. http://dx.doi.org/10.3390/app11156860.
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The author has derived the closed-form dynamic equations for a planar musculoskeletal chain composed of a generic number n of rigid links connected by ideal revolute joints. Single-joint and multi-joint muscles have been modeled as linear force actuators that can span from one joint to all the joints of the chain. The generic shape and size of each individual link of the chain accounts for different alignments among the center of mass of the link, the centers of rotation of the joints that articulate the link with its neighbors, and the points of application of the muscle forces and the possible contact external resistances acting on the link. The joint torque and the reaction force acting on each joint have been determined in closed-form by analytical quantification of the unique contribution of each individual kinematic and kinetic variable: (1) force of each single-joint or multi-joint muscle spanning or non-spanning the joint; (2) weight and contact external resistances acting on each individual link of the chain; (3) position, angular velocity, and angular acceleration of each individual link of the chain. The analytical results derived in this study can be applied to multilink musculoskeletal chains with deep/superficial and segmental/global muscles.
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Weinhandl, Joshua T., Bobbie S. Irmischer, and Zachary A. Sievert. "Effects of Gait Speed of Femoroacetabular Joint Forces." Applied Bionics and Biomechanics 2017 (2017): 1–7. http://dx.doi.org/10.1155/2017/6432969.
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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.
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Andrews, J. G., and C. K. Cheng. "The Joint Distribution Problem With Multiple Articular Contact Forces." Journal of Biomechanical Engineering 112, no. 3 (August 1, 1990): 364–66. http://dx.doi.org/10.1115/1.2891197.
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The single joint distribution problem with two or more unknown bony contact forces is considered, and an optimal solution procedure free of ad hoc assumptions is described. If two bony contact forces are present, a strictly muscle force dependent equality constraint exists that allows for initial independent estimation of muscle forces, followed by unique estimation of all bony contact force components perpendicular to the straight line connecting their known points of application. However, if three or more bony contact forces are present, no strictly muscle force dependent equality constraint exists, solution separability is lost, and optimal muscle and bony contact forces are obtained simultaneously.
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Urbonas, Kestutis, and Alfonsas Daniūnas. "COMPONENT METHOD EXTENSION TO STEEL BEAM‐TO‐BEAM AND BEAM‐TO‐COLUMN KNEE JOINTS UNDER BENDING AND AXIAL FORCES." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 11, no. 3 (September 30, 2005): 217–24. http://dx.doi.org/10.3846/13923730.2005.9636353.
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This paper presents an analysis of semi‐rigid beam‐to‐beam end‐plate bolted and beam‐to‐column end‐plate bolted knee joints that are subjected to bending and tension or compression axial force. Usually the influence of axial force on joint rigidity is neglected. According to EC3, the axial load, which is less than 10 % of plastic resistance of the connected member under axial force, may be disregarded in the design of joint. Actually the level of axial forces in joints of structures may be significant and has a significant influence on joint rigidity. One of the most popular practical method permitting the determination of rigidity and strength of joint is the so‐called component method. The extension of the component method for evaluating the influence of bending moment and axial force on the rigidity and strength of the joint are presented in the paper. The numerical results of calculations of rigidity and strength of beam-to-beam and beam-to-column knee joints are presented in this paper as well.
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Beards, C. F., and A. Woowat. "The Control of Frame Vibration by Friction Damping in Joints." Journal of Vibration and Acoustics 107, no. 1 (January 1, 1985): 26–32. http://dx.doi.org/10.1115/1.3274711.
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Some effects of friction damping occurring in joints on the frequency response of a portal frame are presented and discussed. The frame was designed so that the joint clamping forces could be varied, allowing some control of the friction damping caused by interfacial slip in the joints. It was found that a joint clamping force less than that required to tightly fasten a joint gave a minimum frame response: reducing the clamping force from 15 kN to 320 N caused a reduction in frame response of 21 dB. Some changes in resonance frequencies were also observed.
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Hu, Jiayu, Zhenxian Chen, Hua Xin, Qida Zhang, and Zhongmin Jin. "Musculoskeletal multibody dynamics simulation of the contact mechanics and kinematics of a natural knee joint during a walking cycle." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 232, no. 5 (April 11, 2018): 508–19. http://dx.doi.org/10.1177/0954411918767695.
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Detailed knowledge of the in vivo loading and kinematics in the knee joint is essential to understand its normal functions and the aetiology of osteoarthritis. Computer models provide a viable non-invasive solution for estimating joint loading and kinematics during different physiological activities. However, the joint loading and kinematics of the tibiofemoral and patellofemoral joints during a gait cycle were not typically investigated concurrently in previous computational simulations. In this study, a natural knee architecture was incorporated into a lower extremity musculoskeletal multibody dynamics model based on a force-dependent kinematics approach to investigate the contact mechanics and kinematics of a natural knee joint during a walking cycle. Specifically, the contact forces between the femoral/tibial articular cartilages and menisci and between the femoral and tibial/patellar articular cartilages were quantified. The contact forces and kinematics of the tibiofemoral and patellofemoral joints and the muscle activations and ligament forces were predicted simultaneously with a reasonable level of accuracy. The developed musculoskeletal multibody dynamics model with a natural knee architecture can serve as a potential platform for assisting clinical decision-making and postoperative rehabilitation planning.
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Bergmann, G., F. Graichen, and A. Rohlmann. "Hip joint forces in sheep." Journal of Biomechanics 32, no. 8 (August 1999): 769–77. http://dx.doi.org/10.1016/s0021-9290(99)00068-8.
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Rusu, Lucian, Cosmina Vigaru, and Dan Ioan Stoia. "Determining the Reaction Forces and Torques that Appeared in the Ankle Joint during Normal Walking." Applied Mechanics and Materials 801 (October 2015): 257–61. http://dx.doi.org/10.4028/www.scientific.net/amm.801.257.
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The human body is a very complex system which is studied by doctors but also by engineers. The human motion analysis is an important topic in the biomechanical field. It is essential to determine the forces and torques that appears in joints during daily activities for the development of implants and prosthesis. The goal of this paper is to establish time variation of force and torque in the human ankle joint during one walking step. For this experiment we used two equipments witch record the ground reaction force respectively the angular motion for the ankle joint. Based on these measurements and using the anthropometric patient parameters we developed an application (using in Matlab – Simulink software) that calculates the forces and torques that appear in the human ankle joint. The application simulates the motion taking into account the mass inertia moments. The results of simulation are the forces and torques that appear in ankle joint. The application can simulate any type of human motion, according to the input data from the excel file. These results can be used further for the optimization of ankle implants or prosthesis.
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Becker, Joanne, Emmanuel Mermoz, and Jean-Marc Linares. "Determination of biological joint reaction forces from in-vivo experiments using a hybrid combination of biomechanical and mechanical engineering software." Mechanics & Industry 21, no. 6 (2020): 623. http://dx.doi.org/10.1051/meca/2020088.
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In biomechanical field, several studies used OpenSim software to compute the joint reaction forces from kinematics and ground reaction forces measurements. The bio-inspired joints design and their manufacturing need the usage of mechanical modeling and simulation software tools. This paper proposes a new hybrid methodology to determine biological joint reaction forces from in vivo measurements using both biomechanical and mechanical engineering softwares. The methodology has been applied to the horse forelimb joints. The computed joint reaction forces results would be compared to the results obtained with OpenSim in a previous study. This new hybrid model used a combination of measurements (bone geometry, kinematics, ground reaction forces…) and also OpenSim results (muscular and ligament forces). The comparison between the two models showed values with an average difference of 8% at trotting and 16% at jumping. These differences can be associated with the differences between the modelling strategies. Despite these differences, the mechanical modeling method allows the computation of advanced simulations to handle contact conditions in joints. In future, the proposed mechanical engineering methodology could open the door to define a biological digital twin of a quadruped limb including the real geometry modelling of the joint.
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Dhaher, Yasin Y., and Leonard E. Kahn. "The Effect of Vastus Medialis Forces on Patello-femoral Contact: A Model-based Study." Journal of Biomechanical Engineering 124, no. 6 (December 1, 2002): 758–67. http://dx.doi.org/10.1115/1.1516196.
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A mathematical model of the patello-femoral joint was introduced to investigate the impact of the vastus medialis (longus, obliquus) forces on the lateral contact force levels. In the model, the quadriceps were represented as five separate forces: vastus lateralis, vastus intermedius, rectus femoris, vastus medialis longus (VML), and obliquus (VMO). By varying the relative force generation ratios of the quadriceps heads, the patello-femoral contact forces were estimated. We sought to analytically determine the range of forces in the VMO and VML that cause a reduction or an increase of lateral contact forces, often the cause of patello-femoral pain. Our results indicated that increased contact forces are more dependent on combinations of muscle forces than solely VMO weakness. Moreover, our simulation data showed that the contact force levels are also highly dependent on the knee flexion angle. These findings suggest that training targeted to reduce contact forces through certain joint angles could actually result in a significant increase of the contact forces through other joint angles.
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Hurley, G. R. B., R. McKenney, M. Robinson, M. Zadravec, and M. R. Pierrynowski. "The role of the contralateral limb in below-knee amputee gait." Prosthetics and Orthotics International 14, no. 1 (April 1990): 33–42. http://dx.doi.org/10.3109/03093649009080314.
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Very little quantitative biomechanical research has been carried out evaluating issues relevant to prosthetic management. The literature available suggests that amputees may demonstrate an asymmetrical gait pattern. Furthermore, studies suggest that the forces occurring during amputee gait may be unequally distributed between the contralateral and prosthetic lower limbs/This study investigates the role of the contralateral limb in amputee gait by determining lower limb joint reaction forces and symmetry of motion in an amputee and non-amputee population. Seven adult below-knee amputees and four non-amputees participated in the study. Testing involved collection of kinematic coordinate data employing a WATSMART video system and ground reaction force data using a Kistler force plate. The degree of lower limb symmetry was determined using bilateral angle-angle diagrams and a chain encoding technique. Ankle, knee and hip joint reaction forces were estimated in order to evaluate the forces acting across the joints of the amputee's contralateral limb. The amputees demonstrated a lesser degree of lower limb symmetry than the non-amputees. This asymmetrical movement was attributed to the inherent variability of the actions of the prosthetic lower limb. The forces acting across the joints of the contralateral limb were not significantly higher than that of the non-amputee. This suggests that, providing the adult amputee has a good prosthetic fit, there will not be increased forces across the joints of the contralateral limb and consequently no predisposition for the long-term wearer to develop premature degenerative arthritis.
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Dallmann, Chris J., Volker Dürr, and Josef Schmitz. "Joint torques in a freely walking insect reveal distinct functions of leg joints in propulsion and posture control." Proceedings of the Royal Society B: Biological Sciences 283, no. 1823 (January 27, 2016): 20151708. http://dx.doi.org/10.1098/rspb.2015.1708.
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Determining the mechanical output of limb joints is critical for understanding the control of complex motor behaviours such as walking. In the case of insect walking, the neural infrastructure for single-joint control is well described. However, a detailed description of the motor output in form of time-varying joint torques is lacking. Here, we determine joint torques in the stick insect to identify leg joint function in the control of body height and propulsion. Torques were determined by measuring whole-body kinematics and ground reaction forces in freely walking animals. We demonstrate that despite strong differences in morphology and posture, stick insects show a functional division of joints similar to other insect model systems. Propulsion was generated by strong depression torques about the coxa–trochanter joint, not by retraction or flexion/extension torques. Torques about the respective thorax–coxa and femur–tibia joints were often directed opposite to fore–aft forces and joint movements. This suggests a posture-dependent mechanism that counteracts collapse of the leg under body load and directs the resultant force vector such that strong depression torques can control both body height and propulsion. Our findings parallel propulsive mechanisms described in other walking, jumping and flying insects, and challenge current control models of insect walking.
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Li, Bo, San-Min Wang, Viliam Makis, and Xiang-Zhen Xue. "Dynamic characteristics of planar linear array deployable structure based on scissor-like element with differently located revolute clearance joints." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 232, no. 10 (May 22, 2017): 1759–77. http://dx.doi.org/10.1177/0954406217710277.
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This paper comprehensively investigates the parametric effects of differently located revolute clearance joints on the dynamic behavior of planar deployable structure based on scissor-like element. Considering the real physical mechanical joints, the normal and the tangential forces in the revolute clearance joints are respectively modeled using Flores contact-force model and LuGre friction model. The resulting forces and moments are embedded in the equations of motion of the scissor deployable structure for accurately describing the effect of joint clearance and governing the dynamic response of this structure. The effects of the main parameters such as the location of the clearance joint, the clearance size and the number of clearance joints on the dynamic characteristics of a multibody mechanical system have been numerically evaluated, and the results indicate that joints at different locations in a mechanical system have different sensitivities to the clearance size, and the more sensitive joint should be controlled to reduce the nonlinear behavior of this structure. Also, it can be concluded that the motion in one revolute clearance joint will affect the motion in the other clearance joints and the dynamic interaction of clearance joints is the important source of structural behavior change. Therefore, in order to accurately predict the dynamic responses of the mechanical system, the clearance effect of each joint on the multibody system should be investigated and understood.
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Masumoto, Junya, and Nobuyuki Inui. "Two heads are better than one: both complementary and synchronous strategies facilitate joint action." Journal of Neurophysiology 109, no. 5 (March 1, 2013): 1307–14. http://dx.doi.org/10.1152/jn.00776.2012.
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If two people lift and carry an object, they not only produce complementary forces on the object but also walk in synchrony. Previous studies have not examined how two types of coordination strategy are adopted simultaneously. The present study thus tested the hypothesis that complementary and synchronous strategies simultaneously facilitate the action coordination performed by two people. Ten pairs of participants produced periodic isometric forces such that the sum of forces they produced was the target force cycling between 5% and 10% of maximum voluntary contraction with an interval of 1,000 ms (joint action), while individuals alone produced the same target forces with the right hand (individual action). The correlation between forces produced by two participants was highly negative when the total force was visible, indicating that the two participants produced complementary forces. When the image of the total or partner force was presented, the coherence between force-time series produced by two participants was highest at 1 Hz. The relative phase angles were also distributed at the 0–20° phase region. These innovative findings indicate that two participants simultaneously adopted both complementary and temporal synchronous strategies exclusively when the total force was visible. With the vision of total force, surprisingly, while the joint action exhibited a less variable force than the individual action, the joint action exhibited a smaller absolute error of forces than the individual action. These new findings indicated that the joint action controlled force more accurately than the individual action.
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Ji, Jiancheng, Shuai Guo, and Fengfeng (Jeff) Xi. "Force Analysis and Evaluation of a Pelvic Support Walking Robot with Joint Compliance." Journal of Healthcare Engineering 2018 (November 28, 2018): 1–12. http://dx.doi.org/10.1155/2018/9235023.
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The force analysis of a pelvic support walking robot with joint compliance is discussed in this paper. During gait training, pelvic motions of hemiplegic patients may be excessively large or out of control; however, restriction of pelvic motions is not likely to facilitate successful rehabilitation. A robot-assisted pelvic balance trainer (RAPBT) is proposed to help patients control the range of motion via force field, and force analysis is necessary for the control of the compliant joints. Thus, kinematic model and static model are developed to derive the Jacobian and the relation between the interaction forces and the pelvic movements, respectively. Since the joint compliance is realized through a nontorsional spring, a conventional (linear) Jacobian method and a piecewise linear method are derived to relate the interaction forces with the pelvis movements. Three preliminary experiments are carried out to evaluate the effectiveness of the proposed methods and the feasibility of the RAPBT. The experiment results indicate that the piecewise linear method is effective in the calculation of the interaction forces. Gait with pelvic brace strongly resembles free overground walking and partly decreases motion range via force field. The findings of this research demonstrate that the pelvic brace with joint compliance may provide effective interventions.
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Fujie, Hiromichi, Kiyoshi Mabuchi, Savio L. Y. Woo, Glen A. Livesay, Shinji Arai, and Yukio Tsukamoto. "The Use of Robotics Technology to Study Human Joint Kinematics: A New Methodology." Journal of Biomechanical Engineering 115, no. 3 (August 1, 1993): 211–17. http://dx.doi.org/10.1115/1.2895477.
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Robotics technologies have been modified to control and measure both the force and position of synovial joints for the study of joint kinematics. One such system was developed to perform kinematic testing of a human joint. A 6-axis articulated robotic manipulator with 6 degrees of freedom (DOF) of motion was designed and constructed; a mathematical description for joint force and position was devised; and hardware and software to control forces applied to the joint, as well as position of the joint, were developed. The new methodology was utilized to simulate physiological loading conditions and to perform an anterior-posterior (A-P) translation test on a human cadaveric knee. Testing showed that this new system can simulate complex loading conditions and also measure the resulting joint kinematics.
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Choi, Jin Ho, Young Hwan Lee, Jin Hwe Kweon, and Woo Seong Che. "Strength of Composite Laminated Bolted Joint Subjected to a Clamping Force." Key Engineering Materials 326-328 (December 2006): 1777–80. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.1777.
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As these composites have become more popular, composite joint design has become a very important research area, as these joints are often the weakest parts of composite structures. In this paper, the strength of a composite laminated bolted joint being subjected to a clamping force was tested and predicted using the FAI (Failure Area Index) method. The strengths of composite joints subjected to clamping forces on different geometric shapes and dimensions were predicted using the FAI method, and the results were compared with experimental results. From the tests and analyses, the strength of a given composite laminated bolted joint subjected to a clamping force could be predicted within 22.5% via the FAI method.
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Qin, Haojie, Yuwen Li, and Xiong Xiong. "Workpiece Pose Optimization for Milling with Flexible-Joint Robots to Improve Quasi-Static Performance." Applied Sciences 9, no. 6 (March 13, 2019): 1044. http://dx.doi.org/10.3390/app9061044.
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Although industrial robots are widely used in production automation, their applications in machining have been limited because of the structural vibrations induced by periodic cutting forces. Since the dynamic characteristics of an industrial robot depends on its configuration, the responses of the robot structure to the cutting forces are affected by how the workpiece is placed within the workspace of the robot. This paper presents a method for workpiece pose optimization for a robotic milling system to improve the quasi-static performance during machining. Since the milling forces are time-varying due to the characteristics of the multi-tooth and discontinuity of milling, these forces can excite vibrations inside the robot structure. To address this issue, a structural dynamics model is established for industrial robots, considering their joint flexibility, and a milling force formulation is incorporated into the robot dynamics model to investigate the forced vibrations of the flexible joints. Then, the quasi-static performance of the robotic machining system is evaluated by the vibration-induced offset of the cutter tool that is mounted on the end-effector. Finally, an optimization approach is given for the workpiece pose to minimize the cutter tool offset under the periodic milling force. A numerical simulation demonstrates that the optimal workpiece pose can significantly reduce the overall tool offset during machining and can lower the variation of the tool offset along the milling path.
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Koblauch, Henrik, Thomas Heilskov-Hansen, Tine Alkjær, Erik B. Simonsen, and Marius Henriksen. "The Effect of Foot Progression Angle on Knee Joint Compression Force During Walking." Journal of Applied Biomechanics 29, no. 3 (June 2013): 329–35. http://dx.doi.org/10.1123/jab.29.3.329.
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It is unclear how rotations of the lower limb affect the knee joint compression forces during walking. Increases in the frontal plane knee moment have been reported when walking with internally rotated feet and a decrease when walking with externally rotated feet. The aim of this study was to investigate the knee joint compressive forces during walking with internal, external and normal foot rotation and to determine if the frontal plane knee joint moment is an adequate surrogate for the compression forces in the medial and lateral knee joint compartments under such gait modifications. Ten healthy males walked at a fixed speed of 4.5 km/h under three conditions: Normal walking, internally rotated and externally rotated. All gait trials were recorded by six infrared cameras. Net joint moments were calculated by 3D inverse dynamics. The results revealed that the medial knee joint compartment compression force increased during external foot rotation and the lateral knee joint compartment compression force increased during internal foot rotation. The increases in joint loads may be a result of increased knee flexion angles. Further, these data suggest that the frontal plane knee joint moment is not a valid surrogate measure for knee joint compression forces but rather indicates the medial-to-lateral load distribution.
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Duong, Bien Xuan, My Anh Chu, and Khoi Bui Phan. "Inverse dynamic analyzing of flexible link manipulators with translational and rotational joints." Science and Technology Development Journal 20, K2 (June 30, 2017): 42–50. http://dx.doi.org/10.32508/stdj.v20ik2.447.
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Inverse dynamic problem analyzing of flexible link robot with translational and rotational joints is presented in this work. The new model is developed from single flexible link manipulator with only rotational joint. The dynamic equations are built by using finite element method and Lagrange approach. The approximate force of translational joint and torque of rotational joint are found based on rigid model. The simulation results show the values of driving forces at joints of flexible robot with desire path and errors of joint variables between flexible and rigid models. Elastic displacements of end-effector are shown, respectively. There are remaining issues which need be studied further in future work because the error joints variables in algorithm to solve inverse dynamic problem of flexible with translational joint has not been mentioned yet.
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Wierzcholski, Krzysztof. "DETERMINATION OF RANDOM FRICTION FORCES ON THE BIOLOGICAL SURFACES OF A HUMAN HIP JOINT WITH A PHOSPHOLIPID BILAYER." Tribologia 284, no. 2 (April 30, 2019): 131–42. http://dx.doi.org/10.5604/01.3001.0013.4163.
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The paper presented concerns a new mathematical form of the stochastic theory of hydrodynamic friction forces occurring on real human hip joint surfaces with a phospholipids bilayer. This paper particularly presents a new review of stochastic analytical considerations realized by the authors for friction forces estimation during hydrodynamic lubrication of biological surfaces performed on the basis of the gap height measurements in the human hip joint. After numerous experimental measurements, it directly follows that the random unsymmetrical increments and decrements of the gap height of human joints have an important influence on the load carrying capacities and finally on the friction forces and wear of cooperating cartilage surfaces. The main topic demonstrates the impact of the variations of expectancy values and the standard deviation of the human joint gap height on the friction forces occurring in the human joint. Moreover, an evident connection is observed between the apparent dynamic viscosity and the features of the cartilage surface coated by the phospholipid cells. Hence, after the abovementioned remarks, follows the corollary that the influence of the gap height stochastic variations and random surfaces coated by the PL cells tend indirectly from the apparent viscosity into the friction force variations. The synthetic, complex elaborations of the results obtained indicate the influence of the random roughness and stochastic growth of living biological cartilage surfaces on the friction forces distribution.
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Shin, Dong Hwan, Tae Sang Park, Choong Pyo Jeong, Yoon Gu Kim, and Ji Nung An. "Study of Torsion Spring’s Parameters with Angular Type Grippers." Advanced Materials Research 502 (April 2012): 355–59. http://dx.doi.org/10.4028/www.scientific.net/amr.502.355.
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Angular type grippers are proper to grip the small size material than linear type grippers (clamping). It is due to the grip force of angular type grippers separates to the normal and the opposite directional force to gravity forces, when the contact between the gripper tip and the gripped material occurs. Whereas, the linear type gripper with prismatic joint has only normal forces. Therefore, even less gripping force of angular type grippers than linear type can generate slip-less pick-and-place motions. But this angular type gripper has some restrictions. For generating the opposite direction force to gravity forces, it is necessary that the length between each angular joint position is larger than the length of gripped materials. This should be considered on the design step of angular type grippers. Otherwise, the gripping force separates to the normal and the same directional force to gravity forces. The other restriction is that the tip of gripper must have passive joint or active joint for the plane-to-plane contact between faces of gripped material and gripper tip, for getting the high frictional coefficient. In this paper, we describe the case of adaptation of passive joint. This leads simpler implementation than the active joint. Especially, we focus on the torsional spring deposed at between jaw link and tip as the passive joint, with effects of design parameters of this torsional spring such as the torsional stiffness and preload with multi-body dynamics simulation.
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Martelli, Saulo, Daniela Calvetti, Erkki Somersalo, and Marco Viceconti. "Stochastic modelling of muscle recruitment during activity." Interface Focus 5, no. 2 (April 6, 2015): 20140094. http://dx.doi.org/10.1098/rsfs.2014.0094.
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Muscle forces can be selected from a space of muscle recruitment strategies that produce stable motion and variable muscle and joint forces. However, current optimization methods provide only a single muscle recruitment strategy. We modelled the spectrum of muscle recruitment strategies while walking. The equilibrium equations at the joints, muscle constraints, static optimization solutions and 15-channel electromyography (EMG) recordings for seven walking cycles were taken from earlier studies. The spectrum of muscle forces was calculated using Bayesian statistics and Markov chain Monte Carlo (MCMC) methods, whereas EMG-driven muscle forces were calculated using EMG-driven modelling. We calculated the differences between the spectrum and EMG-driven muscle force for 1–15 input EMGs, and we identified the muscle strategy that best matched the recorded EMG pattern. The best-fit strategy, static optimization solution and EMG-driven force data were compared using correlation analysis. Possible and plausible muscle forces were defined as within physiological boundaries and within EMG boundaries. Possible muscle and joint forces were calculated by constraining the muscle forces between zero and the peak muscle force. Plausible muscle forces were constrained within six selected EMG boundaries. The spectrum to EMG-driven force difference increased from 40 to 108 N for 1–15 EMG inputs. The best-fit muscle strategy better described the EMG-driven pattern ( R 2 = 0.94; RMSE = 19 N) than the static optimization solution ( R 2 = 0.38; RMSE = 61 N). Possible forces for 27 of 34 muscles varied between zero and the peak muscle force, inducing a peak hip force of 11.3 body-weights. Plausible muscle forces closely matched the selected EMG patterns; no effect of the EMG constraint was observed on the remaining muscle force ranges. The model can be used to study alternative muscle recruitment strategies in both physiological and pathophysiological neuromotor conditions.
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Choi, Hyeon Ki, Min Jwa Seo, Ja Choon Koo, Hyeon Chang Choi, and Won Hak Cho. "The Effects of Muscle Forces on Ankle Joint Kinetics during Postural Balance Control." Key Engineering Materials 326-328 (December 2006): 871–74. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.871.
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We assessed the effects of muscle forces on ankle joint kinetics during postural balance control of human boy. Nine male subjects (mean age of 25.8 yrs) participated in the experiment. An ankle joint model assumed ball and socket joint was used, which was capable of three dimensional rotations. A six-camera VICON system was used for motion analysis. Waist pulling system and force platform were adopted for forward sway and GRF (ground reaction force) measurement. We used linear optimization programs to calculate the variation of muscle forces and angular displacements of shank and foot segments. With the experimental data and linear programs, we could calculate joint reaction forces, and bone-on-bone forces. The results presented in this study give us the insights to understand the roles of lower limb muscles during postural balance control and ankle injury mechanism.
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NADI, AZADEH, MOHAMMAD TAGHI KARIMI, FRANCIS FATOYE, and AZADEH JAFARI. "THE EFFECTS OF SCOLIOSIS ON SPINAL MUSCLES LENGTH AND JOINT CONTACT FORCES." Journal of Mechanics in Medicine and Biology 18, no. 06 (September 2018): 1850022. http://dx.doi.org/10.1142/s0219519418500227.
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Background: Although there are a few studies on kinetic and kinematic parameters of scoliotic subjects, it is still controversial whether gait performance of scoliotic subjects differs from that of normal subjects or not. Moreover, there is lack of information regarding joint contact force of scoliotic on convex and concave sides. Therefore, this study examined these issues. Method: Two groups of children (healthy and children with scoliosis, each group consisting of 5 subjects) participated in this study. The force applied on leg and motions of body parts were evaluated using a Kistler force plate and motion analysis system, respectively. Joint contact forces, muscles length were evaluated in both groups and on both sides (in scoliotic subjects) with OpenSim software. The difference in the parameters between healthy children and scoliotic subjects, and also concave and convex sides, was determined using the independent [Formula: see text] test. [Formula: see text] value was set at [Formula: see text]. Results: The results of this study showed that there was no difference between the forces applied on the leg, range of motions of the joints (hip, knee, ankle, pelvic and trunk), muscles length and joint contact force, neither between normal and children with scoliosis, nor between concave and convex sides [Formula: see text]. Conclusion: The findings revealed that scoliosis deformity with curve less than [Formula: see text] does not have any significant effect on joint contact force, kinetic and kinematic parameters.
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Nha, Kyung Wook, Ariunzaya Dorj, Jun Feng, Jun Ho Shin, Jong In Kim, Jae Ho Kwon, Kyungsoo Kim, and Yoon Hyuk Kim. "Application of Computational Lower Extremity Model to Investigate Different Muscle Activities and Joint Force Patterns in Knee Osteoarthritis Patients during Walking." Computational and Mathematical Methods in Medicine 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/314280.
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Many experimental and computational studies have reported that osteoarthritis in the knee joint affects knee biomechanics, including joint kinematics, joint contact forces, and muscle activities, due to functional restriction and disability. In this study, differences in muscle activities and joint force patterns between knee osteoarthritis (OA) patients and normal subjects during walking were investigated using the inverse dynamic analysis with a lower extremity musculoskeletal model. Extensor/flexor muscle activations and torque ratios and the joint contact forces were compared between the OA and normal groups. The OA patients had higher extensor muscle forces and lateral component of the knee joint force than normal subjects as well as force and torque ratios of extensor and flexor muscles, while the other parameters had little differences. The results explained that OA patients increased the level of antagonistic cocontraction and the adduction moment on the knee joint. The presented findings and technologies provide insight into biomechanical changes in OA patients and can also be used to evaluate the postoperative functional outcomes of the OA treatments.
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Martin, Heiner, Michael Stiehm, Ingmar Rinas, Niels Grabow, and Thomas Mittlmeier. "Testing of dynamic wrist joint external fixator mobility and reaction moment." Current Directions in Biomedical Engineering 4, no. 1 (September 1, 2018): 447–48. http://dx.doi.org/10.1515/cdbme-2018-0106.
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AbstractFor the investigation of reaction moments of wrist joint with external fixator, a test device was developed that allows a well-defined investigation of the joint loads during hand flexion movements. The reaction moments are considered as a measure for the joint loads due to the constraint forces, which occur with differences of the rotation axis of the fixator device from the physiological rotation axis of the wrist joint. The developed test device allows a dynamic momentum load application into the wrist by a servohydraulic testing machine. This testing device converts the force to a moment by a constant lever arm and allows thereby the measurement of the reaction moments by the force load cell of the testing machine. Measurements on cadaveric wrist joints with external fixator can be thereby performed under reproducible conditions. The cadaveric wrist joints can be integrally casted into bone cement and thereby clamped to the testing device. Preliminary experiments with artificial bones showed that forces within the measuring range of the load cell of the testing machine can be measured. The design of the test device is presented. Hence, the requirements for measurements of the reaction moments with wrists with external fixator for distal radius fractures under dynamic loads are created.