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Öğe A Motion-impedance-force Controller for Uncertain Robotic Systems(Inst Control Robotics & Systems, Korean Inst Electrical Engineers, 2025) Baran, Eray A.; Uzunovic, Tarik; Ozcelik, I. Turac; Dzakmic, Sejla; Sabanovic, AsifOver the last decades, issues related to the impedance and the force control and their integration with motion control for uncertain plants are attracting considerable interest. This paper discusses a controller that can realize these three control strategies without changing the structure or the controller parameters. The proposed controller can simultaneously achieve motion tracking, compliance with a desired impedance during interaction, and pure force control when regulating interaction forces. A key feature of the controller is its ability to smoothly alternate between these modes in unstructured environments, without requiring a mode recognition mechanism. The detailed controller design incorporates operational space dynamics, enabling dynamic adjustment of control strategies based on both position and force tracking errors. This approach provides a robust and flexible solution for robotic systems operating in environments with varying levels of uncertainty and interaction force demands. Simulations and experimental results demonstrate the effectiveness and robustness of the proposed system in achieving high-performance task execution across all operational modes.Öğe A multiple sensor fusion based drift compensation algorithm for mecanum wheeled mobile robots(Tubitak Scientific & Technological Research Council Turkey, 2021) Alhalabi, Abdulrahman; Ezim, Mert; Canbek, Kansu Oguz; Baran, Eray A.This paper investigates a multiple sensor fusion based drift compensation technique for a mecanum wheeled mobile robot platform. The mobile robot is equipped with high-precision encoders integrated to the wheels and four accelerometers placed on its chassis. The proposed algorithm combines the information from the encoders and the acceleration sensors to estimate the total drift in the acceleration dimension. The inner loop controller is designed utilizing a disturbance-observer-based acceleration control structure which is blind against the slipping motion of the wheels. The estimated drift acceleration from the sensor fusion is then mapped back to the joint space of the robot and used as additional compensation over the existing controllers. The proposed algorithm is tested on a series of experiments. The results of the experiments are also compared with those of a recent study in order to provide a benchmark evaluation. The enhanced tracking performance yielding towards smaller error magnitudes in the experiments illustrate the efficacy and success of the proposed control architecture in attenuating the positioning drift of mecanum wheeled robots.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 A softgrowing robotic system for odor detection and classification(Cambridge Univ Press, 2026) Oyejide, Ayodele James; Astar, Ahmet; Kaya, Gulnur; Yaqub, Ustaz Abdulfattah; Baran, Eray A.; Stroppa, FabioOdor classification is essential in environmental monitoring, gas leak detection, and industrial safety. Although conventional mobile robotic platforms equipped with electronic noses offer advanced gas-sensing capabilities, their performance in confined or cluttered environments is often constrained by rigid structures and limited maneuverability. In this work, we present an olfactory softgrowing robot (oSGR) that integrates bio-inspired, growth-based locomotion with machine-learning (ML)-driven odor classification. Our system comprises a pressurized base enabling contact-free eversion and a custom motorized tip mount housing a multi-sensor array of four metal oxide TGS sensors (2600, 2602, 2611, and 2620) coupled with a passive aspirator for volatile organic compound (VOC) sampling. We provide detailed modeling, design, and structural characterization of the tip mount under multiple actuation configurations, and demonstrate the robot's olfactory capability through experiments involving four VOCs - ethanol, methane, gin, and acetone. We evaluated two experimental modes: (i) in-transit and static sampling at fixed distances ( $20$ , $40$ , and $80$ cm from the source), and (ii) continuous sampling during transit at speeds of $5$ cm/s and $10$ cm/s. The collected olfactory dataset was used to train twelve widely employed supervised ML classifiers in gas sensing, including k-Nearest Neighbors (kNN), Random Forest, and Linear Discriminant Analysis. The kNN classifier achieved the highest accuracy (99.88%), demonstrating strong robustness for the olfactory data. Our results highlight the potential of SGRs for contact-free, continuous, in-motion chemical sensing. This unique data acquisition approach reduces detection latency and energy consumption typically associated with conventional stop-and-sense strategies.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 Bilateral Control With Continuously Variable Scaling(IEEE, 2018) Oztoprak, Burak; Baran, Eray A.; Sabanovic, AsifThis paper proposes a method for the scaled bilateral teleoperation with continuously variable position and force scaling. In the proposed method, the controller is reformulated to synchronize the forces and velocities which provides the operator with the ability to change the scaling gains during operation. For the derivation of the controller, exponentially decaying error dynamics are preferred over the assumption of disturbance compensation with Disturbance Observers (DOB). Following the mathematical derivation, the algorithm is tested on a setup containing single DOF master and slave robots with the ability of giving force feedback to the operator. In order to provide a complete analysis, several different sets of experiments are made with sinusoidal velocity and force scales having different amplitudes and frequencies. Experiment results illustrate the successful tracking responses and stable operation of the proposed control scheme for the continuously varying velocity and force scales.Öğe Bilateral teleoperation with continuously variable scaling and PD force control(Sage Publications Ltd, 2021) Oztoprak, Burak; Baran, Eray A.; Sabanovic, AsifThis paper investigates the bilateral teleoperation with the possibility of continuously variable scaling during real-time operation. The algorithm proposed for this purpose provides the operator with the ability to change the scaling gains of force and velocity loops during operation. The controllers are derived to enforce exponentially decaying error dynamics on systems which have inner loop disturbance compensation. The proposed architecture assumes the scale factors as continuous functions of time which have continuous derivatives that are also included in the mathematical derivation. Unlike the existing studies, the presented framework allows real-time adaptation of scaling gains, which provides the user with the ability to conduct coarse and fine motion in the same operation. The Lyapunov stability proof of the proposed method is made and the margins of the controller gains are identified for practical operation. Furthermore, the operational accuracy is enhanced by the application of a PD force control loop which is also new for scaled bilateral teleoperation. The realization of PD loop is made using an alpha-beta-gamma filter to differentiate the force signal. The algorithm is validated on a setup consisted of two single DOF motion control systems. In order to provide a complete analysis, a wide range of experiments are made, velocity and force scales having sinusoidal patterns with different amplitudes and frequencies. Moreover, comparison with a classical bilateral control architecture is made to highlight the flexibility of the proposed control method. The efficacy of the proposed approach is solidified by the successful tracking responses obtained from these experiments.Öğe Collagen-carrageenan-chitosan sponge reinforced with 3D-printed polycaprolactone mesh for skin tissue engineering(Wiley, 2026) Yesiloglu, Buket; Barer, Neslihan; Baran, Eray A.; Serin, Erdal; Dalgic, Ali Deniz; Erdemli, Bengi Yilmaz; Tahmasebifar, AydinBiopolymers have gained prominence due to their potential in tissue engineering, which includes hydrophilicity, lower toxicity, reduced immune rejection, biocompatibility and biodegradability. However, biopolymers typically exhibit low mechanical strength, which decreases their application potential in tissue engineering. Composites of natural and synthetic polymers offer a robust solution to overcome this challenge, as the stiffness and durability of composites are enhanced by the presence of synthetic polymers. This study investigates two composite sandwich model scaffolds for skin tissue engineering, focusing on their structural and regenerative properties. The composite scaffolds were fabricated by combining freeze-drying and 3D-printing techniques. The outer layers of the scaffolds were fabricated using collagen-carrageenan (CO/CA-PCL) or collagen-carrageenan-chitosan (CO/CA/CH-PCL) through freeze drying, whereas the core layer was formed by 3D-printed polycaprolactone (PCL) mesh. Crosslinking was achieved in the vapor phase of glutaraldehyde and scaffold groups preserved their structure through 28 days after an initial weight loss on day 1. The CO/CA/CH-PCL scaffold showed a lower degradation rate with a cumulative weight loss of 28.6 +/- 5.5% compared to the CO/CA-PCL scaffold which indicates improved stability of the three-polymer sponge. Both scaffolds achieved water retention above 800% after 14 days of incubation which is critical for wound healing. Tensile strength of both scaffolds was successfully supported by 3D-printed PCL mesh. In vitro study has shown that the chitosan-bearing CO/CA/CH-PCL scaffold is promising for use in skin tissue engineering by supporting L929 attachment and high L929 cell viability. (c) 2025 Society of Chemical Industry.Öğe Comparative Analysis of a Selected DCT-Based Compression Scheme for Haptic Data Transmission(IEEE-Inst Electrical Electronics Engineers Inc, 2016) Baran, Eray A.; Kuzu, Ahmet; Bogosyan, Seta; Gokasan, Metin; Sabanovic, AsifIn this study, a novel compression and decompression algorithm, namely the selected discrete cosine transform (DCT), is presented for implementation in networked motion control systems. The proposed method relies on the utilization of a selection algorithm based on bubble sorting to choose the highest power coefficients of the signal obtained by using DCT. In order to better illustrate the effectiveness of the proposed method, comparisons are made with the methods existing in the literature. To this aim, the basics of the compression schemes used in the comparison, namely, the DCT, discrete Fourier transform, and wavelet packet transform, are also briefly discussed followed by the derivation of the proposed method. The algorithmic bases of all four schemes are given to provide further reference for practical applications. The proposed method is tested on an experimental platform consisting of a single-single-degree-of-freedom master and slave systems, and the results are comparatively analyzed based on relevant performance evaluation metrics. The obtained results demonstrate the improvement achieved by the proposed compression scheme over the existing compression methods used in network-based motion control applications, hence proving the feasibility of the approach in tele-operation systems.Öğe Development of a disposable Silicone-Graphite composite strain sensor for soft robotics applications(Elsevier Science Sa, 2025) Akcan, O. Gokalp; Gaber, M. Mahmoud; Baran, Eray A.; Gokdel, Y. DaghanThis work proposes a disposable and flexible strain sensor based on Silicone-graphite composite alternative method for strain sensing applications in soft robotic systems. Flexible piezoresistive have emerged as a promising class of sensors due to their exceptional ability to convert mechanical loads electrical output responses. For this purpose, a sensing structure is fabricated using low-cost, disposable, easy-to-fabricate materials, with graphite powder of particle size 16-60 mu m and Silicone being chosen main fabrication materials. Therefore, an innovative material composed of Silicone and graphite is introduced, functioning as a flexible strain sensor. The sensor is formed in a bone-shaped clamped-clamped beam rectangular cross-sectional area (4 x 3 mm). A simple electronic read-out circuitry is also implemented system. The proposed flexible strain sensor structure is shown to be capable of measuring a force resolution 0.22292 mN. The minimum detectable force of the implemented sensor is 0.86 N, with a sensitivity mV/(mN mV). The resolution of the sensor in terms of the normalized voltage change corresponding generated strain ratio is denoted as 3.81x10(-5) (V/V), and the minimum detectable strain ratio is 2x10(-5), sensitivity of 2.6926 (V/V)/(Delta L/L). Finally, it is reported that the sensor exhibits a stretchability approximately 33%.Öğe Drift compensation of a holonomic mobile robot using recurrent neural networks(Springer Heidelberg, 2022) Canbek, Kansu Oguz; Yalcin, Hulya; Baran, Eray A.Mecanum wheeled robots can exhibit serious slippage problems because of the discontinuous contact between the wheels and the ground which negatively influences the overall navigation quality. Addressing this problem, the aim of this paper is to demonstrate how a learning-based method can be used for the estimation of the drifting error from multiple sensors with distinct measurement types. Here, a recurrent neural network (RNN)-based drift compensation algorithm is proposed for the estimation of the positioning drift. In order to improve the positioning performance in dead reckoning the estimated drift is used within the real-time control loop for proper modification of the motion trajectory. During the training phase, the data acquired from the acceleration sensors attached to the robot chassis and the encoders of the wheels of the robot are used as the main features to train a gated recurrent unit-based RNN. The drift estimator is trained using the computer-generated reference position data, and the response position data which is measured using an optoelectronic motion tracking device. The performance of the proposed learning-based drift estimation and control algorithm is validated through a series of experiments. The responses obtained from the experiments are graphically illustrated and the improvements in the positioning performances are numerically evaluated. The results obtained from the experiments illustrate the effective performance of the proposed algorithm by considerably decreasing the positioning errors.Öğe Enhanced performance of a parallel manipulator with hybrid joint-space and task-space control approaches ( Volume 43 , Issue 3 ,2025, pp. 1043 - 1066)(Cambridge Univ Press, 2025) Sincar, Eyyup; Bayraktaroglu, Zeki Y.; Baran, Eray A.; Emre, Evren[Abstract Not Available]Öğe Flexible Linear Absolute Encoder System for Force Localization in Soft Environments(IEEE, 2020) Erdil, Kuter; Korkut, Dogukan; Akcan, O. Gokalp; Muslu, Batin; Gokdel, Y. Daghan; Baran, Eray A.This paper proposes a novel disposable linear absolute encoder system and its peripheral electronic readout circuitry to be used for the localization of force in a continuum media such as a flexible robotic arm. The proposed structure relies on the design of graphite layers on a flexible surface that shows varying resistance based on the applied strain. The proposed topology can localize the force applied on a continuous paper based sensor having the geometry of an absolute encoder system. The successful results obtained from the experiments prove the efficacy of the proposed system while opening new paradigms for the possibility of contact force localization in flexible structures like soft robots.Öğe Improved bilateral teleoperation with proactive haptic sensing and transmission(Sage Publications Ltd, 2018) Kuzu, Ahmet; Baran, Eray A.; Bogosyan, Seta; Gokasan, Metin; Sabanovic, AsifThis article presents a novel master-slave control configuration that is experimentally demonstrated to improve teleoperation performance under random network delay. This is achieved via the design of a proactive haptic sensing system based on a laser range sensor on the slave side, which in turn allows for the proactive transmission of force control from the master to the slave, thus compensating for Internet-based network delays. The proposed configuration introduces three main contributions to the literature of bilateral control systems: (1) fully decoupled position and force control systems, which allow for the controller gains of each loop to be tuned independently, eliminating the trade-off common to most previous literature; (2) a novel approach that exploits the slow variation nature of the environment parameters, resulting in a lower bandwidth requirement in comparison to previous force control methods; (3) capability to measure the slave environment location and the prediction of the contact force as a result, which provides the human operator with the capability to generate the reaction force proactively on the master side. The conducted experiments demonstrated a significantly improved performance in terms of synchronized forces and positions despite the random network delay between the master and slave systems.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 Numerical Evaluation of Transparency in Teleoperation Systems(Ieee-Inst Electrical Electronics Engineers Inc, 2025) Majeed, Fatimah J.; Baran, Eray A.Evaluation of the performance of teleoperation systems plays an important role in assessing the efficacy and reliability of such systems. The evaluation is usually performed based on factors such as stability, transparency, and user satisfaction. However, very few studies have addressed the numerical evaluation of transparency in teleoperation systems so far. This letter presents a novel method to numerically assess the transparency of teleoperation systems based on representing recorded experimental data algebraically by fitting parametric curves using Elliptic Fourier Descriptors (EFD). The EFD coefficients are used to compute the Hybrid Matrix of the teleoperation system, which provides a metric for judging how transparent a teleoperation system is. This letter validates the proposed method using real experimental position and force data for teleoperation systems with and without time delay, as well as providing an analysis of the effect of the number of harmonics on the calculation of the Hybrid Matrix.Öğe Paper-Based Piezoresistive Force Encoder for Soft Robotic Applications(IEEE-Inst Electrical Electronics Engineers Inc, 2022) Akcan, Omer Gokalp; Erdil, Kuter; Korkut, Dogukan; Baran, Eray A.; Gokdel, Y. DaghanThis work demonstrates the design, implementation, and experimental results of a low-cost disposable flexible sensor system capable of both impact localization and measurement. The proposed flexible sensor structure utilizes a special series of Bristol paper as the main fabrication material, which is coated with electric paint graphite paste and silver paste. The implemented sensor system uses a planar absolute encoder-like sensing topology to locate the impact and has a low-cost and quick manufacturing process. The size of the structure is 210 x 18.56 mm with a thickness of approximately 340 mu m. It has an electronic read-out consisting of three identical Wheatstone bridge circuits and instrumentation amplifiers for each bit. It can detect the external forces in the range of 0.6N to 12N with a spatial resolution of 2.4 cm and 0.55 cm in horizontal and vertical axes, respectively. The proposed sensor structure is tested in a series of experiments using a robotic setup consisted of a pantograph mechanism and a direct drive linear motor. The experiments illustrate the results with measurement sensitivity as small as 1N and proper fatigue resilience against repetitive loads.Öğe Performance Enhancement of a Stewart Platform Using Joint-Task Space Hybrid Control(Ieee, 2025) Sincar, Eyyup; Bayraktaroglu, Zeki Y.; Baran, Eray A.; Emre, EvrenParallel robots offer high precision, stiffness, and dynamic performance, but their nonlinear and coupled dynamics pose challenges for real-time trajectory tracking. This paper presents a hybrid control framework that combines joint-space and task-space controllers to simultaneously manage actuator dynamics and end-effector motion. By leveraging both control domains, the proposed approach addresses the limitations of single-space strategies. Stability is established via Lyapunov analysis, and experimental results confirm superior tracking accuracy compared to conventional acceleration-based controllers, demonstrating effectiveness for high-precision, dynamic applications.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.Öğe Robust Motion Modification for Robot Manipulators in Constrained Environments(IEEE, 2018) Muslu, Batin; Oztoprak, Burak; Baran, Eray A.; Sabanovic, AsifThis paper presents a controller structure for the continuous and robust modification of motion for multi body systems encountering contact with an environment during free motion. The presented algorithm relies on the reformulation of the position tracking error with a term proportional to the reaction force. With the proposed method, fusion of the position and the force controllers can be achieved which provide the robot with certain level of compliance. The derivation of the proposed method is followed by experiments made on a pantograph mechanism actuated by direct drive linear motors. The results obtained from the experiments illustrate the success of the proposed control architecture in providing a natural behavior for the robotic systems working in constrained environments.
