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Abstract This paper presents the mathematical modeling and simulation of a cable-driven robotic device that can be used in gait rehabilitation of patients with lower extremity disabilities. A parallel cable robot is considered to assist a model of human body during walking. First, a proper pattern of walking is considered and kinematic and dynamic equations are solved to obtain tensions in cables for entire cycle of walking. By exploiting a numerical procedure, the workspace of the robot are explored to find suspension points of the cables in which the model remain in controllable workspace of the robot. Remaining of the model in controllable workspace means that cables always remain in tension and robot can effectively engaged in rehabilitation. The optimum locations are determined based on minimum cable tensions (energy consumption) and a Neural Network is trained to quickly determine suspension points based on anthropometric parameters of patient. The simulation results show the effectiveness of the method in tracking of the desired trajectory of walking. The results of this study can be used for development and fabrication of an efficient cable driven rehabilitation system.

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In this paper, designing and fabrication of a prototype of the spider robot is presented. The mechanical and electrical design of the robot is described and then programming and control are addressed. First, after surveying of various mechanisms for legged locomotion, the Klann mechanism has been selected for robot locomotion. The mechanical model has been build using CATIA software and simulations have been done for validation of the performance of the m. The spider-like robot has eight legs. To add the ability of mine detection to the robot, PI metal detector circuit has been designed and made. This circuit has the ability to detect metal but does not recognize the type of metal and its range is about 1 m. Tele-operation control method has been used to control the robot in which the operator can remotely (up to a radius of 300 m) control the robot using a computer. The performance of the robot can be improved using metal detectors circuit. The advantages of spider robot with Klann mechanism is easily tackling of the obstacles and maintaining the balance on uneven terrain or sandy surfaces.

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The main purpose of this paper is to use the concept of manipulability index for finding the optimal link lengths of a surgical robot and then to plan an optimal path for it. This index depends on the configuration of the robot. In each configuration, the manipulability of the robot is calculated thorough the Forward and Inverse Kinematic and Jacobain. In the present paper, a nonlinear constrained optimization problem is formulated based on this index to find the optimum link lengths. The optimization problem is solved using Genetics Algorithm for entire work space of the robot. The manipulability index is calculated all over the workspace using the Mont-Carlo method. Afterward, using this set of optimal link lengths, the optimal path planning is presented in the Cartesian work space. This optimization is done by considering the manipulability criteria while the tracking error is minimized during performing an operation. The suggested procedure is implemented on a four degree of freedom robot manipulator. Several simulations scenarios are presented to demonstrate the capability of the procedure. The simulation results show the efficiency of the method.

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Stratospheric airships have introduced interesting solutions for challenges in aerospace industries. Buoyant and propulsion forces produced by airships makes them to be capable of long-time flight and efficient operation. In spite of many progresses, there are still many challenges in this interesting field of study. In this paper, first the dynamic model of fully-actuated stratospheric airship with 6-DOF expressed by the generalized coordinates, then desired values of the airship attitude, linear and angular velocities obtained according to desired path and using pseudo inversion of the kinematics and dynamics equations. In view of the unknown inertial parameters first in adaptive inverse dynamic control, inertial parameters estimated online by using linearization parameters and gradient update law. Next control law and nonlinear dynamic equation is deduced by designing control algorithm based on passivity, and according to that, adaptive and robust control based on passivity applied for controlling airship. The stability of the closed loop control system is proved by using the Lyapunov stability theory. Finally, comparison between the results of the all methods are shown.