Biodynamics & Biocinematics
Amirhosein Javanfar; Mahdi Bamdad
Volume 16, Issue 2 , September 2022, , Pages 133-145
Abstract
Biomechanical modeling of human joints has been considered for a long time by researchers due to its high importance and application. Therefore, methods of modeling joints, and kinematic and dynamic analysis of human movement have continuously been developing. In this paper, a biomechanical human knee ...
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Biomechanical modeling of human joints has been considered for a long time by researchers due to its high importance and application. Therefore, methods of modeling joints, and kinematic and dynamic analysis of human movement have continuously been developing. In this paper, a biomechanical human knee model is developed, and a generic procedure for dynamic analysis of contact problems in combination with the musculoskeletal model is introduced. The development of this knee dynamic model includes the geometric expression of collision curves and an algorithm for determining collision points. This presentation addresses cartilage penetration depth and contact force calculation through nonlinear discontinuous contact law. Therefore, the femur and tibia's relative motion is modeled through the combined collision reactions of cartilage and bone in the knee. Moreover, two knee models, the novel curve fitted-plane contact model, and the spherical-plane contact model, have been compared, and a personalized model has been developed for such cases as knee osteoarthritis. There is a difference (average 12%) between the results of the enhanced model and the sphere on the plane model in the cartilage penetration. In the simulation, maximum penetration depth in a healthy knee is reported to be 0.705 mm, while in a 75% KOA is 0.521 mm, including 0.5 mm cartilage-cartilage contact and 0.021 mm bone-bone contact. The contact force is not increased in KOA despite the general belief. The cartilage penetration depth exceeds cartilage thickness, and the bone-bone contact leads to pain. It is a suitable tool for the analysis and control of the auxiliary device in order to control the relative motion of the tibia femur and their separation in patients with osteoarthritis of the knee.
Biomechanical Devices
Mohammad Khavary; Mahdi Bamdad
Volume 15, Issue 1 , May 2021, , Pages 13-27
Abstract
Nowadays, one of the most effective tools for restoring patients' mobility and muscles strength is the use of stationary cycling exercises and pedaling. In this study, two methods for the treatment of lower limbs are made possible by the design, control implementation, and construction of an intelligent ...
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Nowadays, one of the most effective tools for restoring patients' mobility and muscles strength is the use of stationary cycling exercises and pedaling. In this study, two methods for the treatment of lower limbs are made possible by the design, control implementation, and construction of an intelligent exercise bike. According to the damage level, the patient will fall into the active-assisted training or passive training group. In a passive training program, patients do not have enough ability to pedal on the bike, so the motor will provide the power to reach a predefined pedaling speed. In this program, feet of patients will pedal at a constant speed above the speed patient is able to achieve compulsorily. In an active-assisted training program, the patient is already improved enough to have a higher ability to pedal at the same constant speed and the motor will provide less power according to the pedaling power of the patient. Hence, the provided power by the motor is set based on the provided force by the patient. In this study, it is aimed to design the control theory for these two treatment methods and this bike. Furthermore, speed control was done by force and speed feedback. Experimental and theoretical results showed that the implementation and equipping of stationary bike with the mentioned method has led the research to the goals of speed control for rehabilitation use. Eventually, the experimental results show an average accuracy of 98.71% for the passive method in the test sample reported in this study and 98.24% for the six tests after reaching a steady state speed. Also, these results are 96.33% for the active-assisted mode and for the test reported in this study; and 95.59% for four tests to reach the desired pedaling speed.
Medical Robotics / Bio-Robotics
Mahya Salem; Saeed Ebrahimi; Mehdi Bamdad
Volume 11, Issue 2 , June 2017, , Pages 111-125
Abstract
In this study, a portable upperlimb exoskeleton is designed for the purpose of rehabilitation and helping the disabled people to do their daily activities. This exoskeleton has two active and one passive degrees of freedom for the shoulder joint. In this system, the idea of cable transmossiom mechanism ...
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In this study, a portable upperlimb exoskeleton is designed for the purpose of rehabilitation and helping the disabled people to do their daily activities. This exoskeleton has two active and one passive degrees of freedom for the shoulder joint. In this system, the idea of cable transmossiom mechanism and guidance pulley with the ability to change the force direction is used. The two active DOFs of the shoulder joint is achived only by pulling one cable for each axis based on the novel design of this mechanism. Each axis of the shoulder is driven independently which implies that a single axis can be installed on the arm. This exoskeleton does not impose any limitation on the vertical motion of the scapula. In addition, it is inexpensive, lightweight and can easily be used. In this paper, after introducing the exoskeleton system, the required motor torques for generating a prescribed task are obtained. In the next step, the kinematic and dynamic equations of this system are derived. By simulating the exoskeleton in CATIA and MATLAB softwares, and presenting the results, the performance of the exoskeleton is evaluated. The results show that this novel exoskeleton system posses an excellent capacity to perform the rehabilitation excersises for shoulder joint.
