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Showing 3 results for Mohammadi Moghaddam
Mohammad Gharini, Majid Mohammadi Moghaddam, Farzam Farahmand,
Volume 17, Issue 1 (3-2017)
Abstract
The purpose of this paper is to investigate the effect of viscoelastic ankle foot prosthesis on below-knee amputee gait cycle by using dynamic simulation of human walking. A two dimensional, seven segment model is developed to simulate normal and amputee entire gait cycle equipped with foot-ground contact model in order to simulate entire gait cycle in an integrated way. In the first step, optimization procedure was coupled with forward dynamic to simulate normal gait cycle. Next step was started by replacing ideal torque generator of ankle joint with passive elements that represents passive prosthetic ankle-foot, in order to simulate below-knee amputee gait cycle. The optimal coefficients of joints that were obtained from dynamic simulation of normal gait cycle were then used for amputee model’s intact joints. Three type of optimal passive ankle foot prosthesis were designed using forward dynamic optimization and the simulation results were employed to compare the performance of different prostheses. The results indicated that using viscoelastic ankle foot prosthesis decreases speed-normalized total work, cost function, dynamic effort and increases speed of the amputee model. Hence using viscoelastic ankle foot prosthesis can improve below-knee amputee walking pattern
Mohammadreza Dehghani Tafti, Majid Mohammadi Moghaddam, Pourya Torabi,
Volume 17, Issue 11 (1-2018)
Abstract
Recently, robotic systems are widely used in surgery, due to their characteristics such as having high precision, being tireless and making no mistakes. They are especially suitable for operation on hard tissue, as the bone is stationary and does not change shape and therefore preoperative planning of the system is much more straightforward. Nevertheless, proposed robotic systems for surgery on skull bone are still in the research stage. In this study, by considering the requirements of craniotomy surgery, a Remote Center of Motion spherical mechanism is used in design and prototyping of a surgical system. The kinematic equations and Jacobian of the mechanism are calculated analytically and later verified through software simulation. Detailed design and force analysis helped selection and use of appropriate AC servo motors for actuation. An aluminum prototype is fabricated out of CNC machined parts. Performance of different connection methods between PC and the robot were tested and a combination of them is proposed for higher reliability and speed. Finally, a software library is generated in LabVIEW environment to simplify the connection with servo motors and utilization and control of the robotic system.
A.r. Abbasi Moshaei, M. Mohammadi Moghaddam, V. Dehghan Neistanak,
Volume 20, Issue 1 (January 2020)
Abstract
Modeling the movement of different parts of the body has been studied a lot in recent years. Body movement models such as fingers movements are good guides for designing different robots. Also, motion disability is one of the common diseases that have a great impact on patients' life quality. To treat the rupture of finger tendon, individual rehearsal rehabilitation exercises for each phalanx is required. In order to achieve this aim and take control of each phalanx movement, the mathematical model of the desired trajectory for each joint is necessary. The angle of each joint is measured with the help of a gyro sensor installed on a novel wearable rehabilitation robot proposed in this paper. The mathematical models of the phalanges motions are obtained by curve fitting. The model is applicable not only in the rehabilitation robots but also in the other robotic works. In most of the works in this area, the desired trajectory diagram was drawn and tracking of the trajectory was investigated. Thus, the desired trajectory formula should be fined for the other works. But in this work, the corresponding formula was found and it can help other researchers to easily use of these formulas for their work. To ensure the accuracy and efficiency of the calculated trajectories, the trajectories are implemented in a control system. In order to control this system, a suitable sliding mode controller was designed and the results of system controlling and trajectory tracking using this controller was obtained.
