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Öğe Design and Actuator Selection of a Lower Extremity Exoskeleton(IEEE-Inst Electrical Electronics Engineers Inc, 2014) Onen, Umit; Botsali, Fatih M.; Kalyoncu, Mete; Tinkir, Mustafa; Yilmaz, Nihat; Sahin, YusufLower extremity exoskeletons are wearable robots that integrate human intelligence with the strength of legged robots. Recently, lower extremity exoskeletons have been specifically developed for transportation of disabled individuals. This paper summarizes the anthropomorphic design of a lower extremity exoskeleton named walking supporting exoskeleton (WSE). WSE has been developed to support some fundamental motions (walking, sitting, standing, etc.) of disabled individuals who lost leg muscular activities completely or partially. WSE has two degrees of freedom per leg which are powered by electrical actuators. This paper discusses critical design criteria considered in mechanical design and actuator selection of WSE.Öğe Force Feedback Control of Lower Extremity Exoskeleton Assisting of Load Carrying Human(Trans Tech Publications Ltd, 2014) Sahin, Yusuf; Botsali, Fatih Mehmet; Kalyoncu, Mete; Tinkir, Mustafa; Onen, Umit; Yilmaz, Nihat; Baykan, Omer KaanLower extremity exoskeletons are wearable robot manipulators that integrate human intelligence with the strength of legged robots. Recently, lower extremity exoskeletons have been specifically developed for rehabilitation, military, industrial applications and rescuing, heavy-weight lifting and civil defense applications. This paper presents controller design of a lower-extremity exoskeleton for a load carrying human to provide force feedback control against to external load carried by user during walking, sitting, and standing motions. Proposed exoskeleton system has two legs which are powered and controlled by two servo-hydraulic actuators. Proportional and Integral (PI) controller is designed for force control of system. Six flexible force sensors are placed in exoskeleton shoe and two load cells are mounted between the end of the piston rod and lower leg joint. Force feedback control is realized by comparing ground reaction force and applied force of hydraulic cylinder. This paper discusses control simulations and experimental tests of lower extremity exoskeleton system.Öğe Mechanical Design of Lower Extremity Exoskeleton Assisting Walking of Load Carrying Human(Trans Tech Publications Ltd, 2014) Sahin, Yusuf; Botsali, Fatih Mehmet; Kalyoncu, Mete; Tinkir, Mustafa; Onen, Umit; Yilmaz, Nihat; Cakan, AbdullahExoskeletons are used in rehabilitation, military, industrial applications and rescuing, heavy-weight lifting and civil defense applications as well. This paper presents to design of a lower-extremity exoskeleton assisting walking of a load carrying human. Proposed exoskeleton system is designed to be appropriate mechanism with human lower extremity and it operates synchronously with the human realizes. The aim of exoskeleton actuator system is to provide forces against to external load carried by user during walking, sitting, and standing motions. Thus, it supports human walking and significant portion of external load carrying by the user. Also it makes possible to user spend less energy, less stress and fatigue. Proposed work involves the following design steps: kinematic synthesis of the exoskeleton, mechanical and electro-hydraulic system design.Öğe Performance comparison of optimization algorithms in LQR controller design for a nonlinear system(Tubitak Scientific & Technological Research Council Turkey, 2019) Onen, Umit; Cakan, Abdullah; Ilhan, IlhanThe development and improvement of control techniques has attracted many researchers for many years. Especially in the controller design of complex and nonlinear systems, various methods have been proposed to determine the ideal control parameters. One of the most common and effective of these methods is determining the controller parameters with optimization algorithms.In this study, LQR controller design was implemented for position control of the double inverted pendulum system on a cart. First of all, the equations of motion of the inverted pendulum system were obtained by using Lagrange formulation. These equations were linearized by Taylor series expansion around the equilibrium position to obtain the state-space model of the system. The LQR controller parameters required to control the inverted pendulum system were determined by using a trial and error method. The determined parameters were optimized by using five different configurations of three different optimization algorithms (GA, PSO, and ABC). The LQR controller parameters obtained as a result of the optimization study with five different configurations of each algorithm were applied to the system and the obtained results were compared with each other. In addition, the configurations that yielded the best control results for each algorithm were compared with each other and the control results were evaluated in terms of response speed and response smoothness.Öğe Vibration analysis of a novel magnetic-viscous nonlinear passive isolator via finite element simulation(Tubitak Scientific & Technological Research Council Turkey, 2019) Meram, Ahmet; Onen, UmitIn this paper, the design and the finite element simulation of a novel magnetic-viscous vibration isolator have been presented. The proposed isolator consists of permanent magnets axially aligned in repulsion position and a viscous damper in parallel with them. The nonlinear spring characteristic of the permanent magnets provides a good damping property with this configuration. Explicit finite element analyses have been conducted to examine the dynamic behavior of the isolator. Output displacements and transmissibility ratios were measured for various magnet configurations, dashpot coefficients, and input displacement excitation frequencies to determine the best damping properties. The results of the finite element modeling revealed that the performance of the isolator is highly sensitive to the quantity of magnets. Isolators with four or more magnets can successfully reduce the output displacement. The results indicate that the isolator significantly reduces the displacement transmissibility in frequencies over the resonant frequency region. It is possible to ensure an infinite operating life for magnet-viscous vibration isolators by protecting the magnets against breakage.