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Öğe Application of Soft Actuation to Bilateral Control and Haptic Reproduction(Inst Control Robotics & Systems, Korean Inst Electrical Engineers, 2022) Sabanovic, Asif; Uzunovic, Tarik; Baran, Eray A.; Yokoyama, Minoru; Shimono, TomoyukiThe main research topic of this paper is to apply the sliding mode based soft actuation to smooth transition between position, force, and impedance control, and realize bilateral control and reproduction of the haptic motion. The proposed design rests on the sliding mode two steps procedure: in the first step, the generalized error - the sliding mode function - is selected in such a way that a closed loop system exhibits a desired dynamics. In the soft actuation method, the generalized error depends on the position and the force, thus allowing the modification of the position tracking if interaction with the environment appears. In the second step, the control is selected to enforce the desired convergence rate and the stability of the closed loop dynamics. The control allows natural - human-like behavior. The application to the bilateral control and reproduction of the haptic motion is discussed in detail and verified by experiments.Öğe Modular and reconfigurable desktop microfactory for high precision manufacturing(Springer London Ltd, 2017) Zhakypov, Zhenishbek; Uzunovic, Tarik; Nergiz, Ahmet Ozcan; Baran, Eray A.; Golubovic, Edin; Sabanovic, AsifSub-millimeter scale devices are developing rapidly taking smaller, smarter, and more precise forms. This is achieved thanks to advancements in micro-manufacturing tools and techniques. For micro-production, a miniaturization of the machinery is a prominent idea that has numerous benefits in terms of material usage, precision, transportation, modularity, and reconfigurability. In this paper, a modular and reconfigurable desktop microfactory for high precision machining and assembly of sub-millimeter scale mechanical parts is presented and experimentally validated. The proposed system is built based on important functional and performance requirements, including miniaturization, high precision operation, modular and reconfigurable design, parallel processing capability, ease of installation, and transportation. The miniature factory consists of five mini processing units; two parallel kinematic robots for manipulation, the laser micro-machining system, the camera system for detection and inspection, and the rotational conveyor system for micro-part delivery. Different configurations of the system layout are proposed taking advantage of their modular design. Experiments are conducted to evaluate the system performance within a single process, like pick-place of a metallic ball with 3 mm diameter, laser machining of a half-millimeter size contour on the surface of the ball, and inspection and verification of the machined contour by means of microscopic camera. The results presented in this work demonstrate micrometer precision operation of the microfactory, showing high potential for manufacturing electro-mechanical devices with ease of readjustment of the microfactory layout.Öğe A novel hybrid contouring control method for 3-DOF robotic manipulators(Pergamon-Elsevier Science Ltd, 2016) Uzunovic, Tarik; Baran, Eray A.; Golubovic, Edin; Sabanovic, AsifA novel controller for three-dimensional contouring control of three-degrees-of-freedom (3-DOF) robotic manipulators is presented in this paper. The proposed controller comprises of an independent joint controller, designed in the configuration space, and a sliding mode controller that enforces desired dynamics for the tracking error projections to the Frenet-Serret frame. Therefore, the presented controller has a hybrid structure and it is named as hybrid contouring controller. In this paper, contour tracking with constant magnitude tangential velocity is discussed. Reference trajectory is generated using the time based spline approximation in order to provide a smooth reference path. The proposed hybrid contouring controller was experimentally compared with the independent joint controller that is designed in the acceleration control framework with disturbance observer. Experimental results, undertaken on a delta robot, showed that hybrid contouring controller outperforms independent joint control architecture. (C) 2016 Elsevier Ltd. All rights reserved.Öğe Performance improvement of bilateral control systems using derivative of force(Cambridge Univ Press, 2018) Baran, Eray A.; Uzunovic, Tarik; Sabanovic, AsifThis paper proposes a bilateral control structure with a realization of the force derivative in the control loop. Due to the inherent noisy nature of the force signal, most teleoperation schemes can make use of only a proportional (P) control structure in the force channel of the bilateral controllers. In the proposed scheme, an alpha-beta-gamma filter is designed to smoothly differentiate the force signal obtained from a reaction force observer integrated to both of the master and slave plants. The differentiated force signal is then used in a proportional-derivative (PD) force controller working together with a disturbance observer. In order to design the overall bilateral controller, an environment model based on pure spring structure is assumed. The controller is designed to enforce an exponentially decaying tracking error for both position and force signals. With the presented controller design approach, one can independently tune the controller gains of the force and the position control channels. The proposed approach is experimentally tested in a platform consisted of direct drive linear motors. As illustrated by the experiment results, the contribution of the PD control in the force channel improves the teleoperation performance especially under hard-contact motion scenarios by attenuating the oscillations, hence, improving the transparency when compared to the structures using only a P force control.
