Hakan Temeltas

Istanbul Technical University · Department of Control Engineering

Imaging science attracts the attention of several researchers from different fields since it involves many application areas and subjects. Two noticeable issues are the imaging of the ground surface and subsurface in this field of science. In the literature, imaging systems are usually integrated into a mobile platform, and the imaging process is p...

Precise localization and autonomous docking at industrial standards are major issues to be handled in order to establish smart factories having end-user oriented production focus and to operate fully autonomous vehicles in the logistics of such factories. Therefore, in this paper, a precise localization algorithm utilizing the affine iterative clos...

Navigation, which is defined as determining the most convenient way to go from one point to another and make the journey on the planned path, is indispensable for developing a fully autonomous system. The navigation stack and its components are a widely studied area in the literature. However, in most of the studies, the developed approaches are te...

The problem of matching point clouds is an efficient way of registration, which is significant for many research fields including computer vision, machine learning, and robotics. There may be linear or non-linear transformation between point clouds, but determining the affine relation is more challenging among linear cases. Various methods have bee...

Most real-world problems are essentially partially observable, and the environmental model is unknown. Therefore, there is a significant need for reinforcement learning approaches to solve them, where the agent perceives the state of the environment partially and noisily. Guided reinforcement learning methods solve this issue by providing additiona...

Bias compensated pseudolinear Kalman filter (BC-PLKF) has been shown to solve the bias problem of pseudolinear Kalman filter (PLKF) and outperform Extended Kalman Filter (EKF) and many others in bearings-only target estimation applications with a low computational cost. However, BC-PLKF assumes that measurement noise is white, which is not a valid...

The localization problem in robotics has been widely studied both for indoor and outdoor applications, but is still open for improvements. In indoor environments, GPS-based methods are not preferred due to reflections, and the pose of the robot is determined according to the measurements taken around with its sensors. One of them is iterative close...

Purpose Heterogeneous teams consisting of unmanned ground vehicles and unmanned aerial vehicles are being used for different types of missions such as surveillance, tracking and exploration. Exploration missions with heterogeneous robot teams (HeRTs) should acquire a common map for understanding the surroundings better. The purpose of this paper is...

Humans and other walking bipeds often encounter and compensate for uneven terrain. They might, for example, regulate the body’s momentum when stepping on stones to cross a stream. We examined what to do and how far to look, as a simple optimal control problem, where forward momentum is controlled to compensate for a step change in terrain height, a...

With the increased use of robots with different performance characteristics in areas such as search and rescue, patrolling and surveillance, the control of multiple robots with unequal capabilities have gained a lot of interest among robotics researchers. Also, the uncertainty of the sensors utilized on the robots for localization has made the prob...

Point set registration is significant for many applications such as recognition and reconstruction problems in computer science, and localization and mapping problems in robotic science. Traditional iterative closest point (ICP) algorithm is fast, but it is only suitable for registration of rigid motions. Traditional affine ICP algorithm is fast en...

Localization is a problem in mobile robotics, which is widely studied and tries to determine the instantaneous position and orientation of the robot. However, the studies that present the necessary infrastructure for real-world applications of the developed methods are in the minority. Therefore, in this study, the architecture required to implemen...

Humans and other walking bipeds often encounter and compensate for uneven terrain. They might, for example, regulate the body momentum when stepping on stones to cross a stream. We examined what to do and how far to look, as a simple optimal control problem, where forward momentum is controlled to compensate for a step change in terrain height and...

The vehicles used for transportation and logistics in the factories usually perceive their surroundings with range sensors. Today, 2D LIDARs are used as range sensors, and 3D LIDARs are becoming widespread with the developments of autonomous vehicle technology. Therefore, Self Adaptive Monte Carlo Localization, abbreviated as SA-MCL, is improved in...

Bu çalı¸şmada afin ICP olarak kısaltılan Afin Ardı¸sık En Yakın Nokta yöntemi kullanılarak hassas konumlama algoritması önerilmiştir. Özü iki nokta bulutu arasındaki dönüşümün iteratif olarak bulunması olan ICP aslında bir nokta bulutu eşleştirme yöntemidir. Ancak bu eşleştirmedeki yüksek performansı nedeniyle konumlama algoritmalarında da kullanıl...

With the emergence of the concept of Industry 4.0, smart factories have started to be planned in which the production paradigm will change. Automated Guided Vehicles, abbreviated as AGV, that will perform load carrying and similar tasks in smart factories, Smart-AGVs, will try to reach their destinations on their own route instead of predetermined...

In this paper, an ellipse based energy calculation algorithm is proposed for Self Adaptive Monte Carlo Localization method, abbreviated as SA-MCL. SA-MCL is a localization method based on particle filters and solves position tracking, global localization and kidnapping problems in localization. The SA-MCL is faster since it uses map energy grids co...

Bipedal locomotion may occur over imperfect surfaces with bumps or other features that disrupt steady gait. An unexpected bump in the road is generally expected to slow down most types of locomotion. On wheels, speed may be regained quite readily with “cruise control” performed in continuous time. But legged locomotion is less straightforward, beca...

Bu çalışmada KU-MCK olarak kısaltılan Kendinden Uyarlamalı Monte Carlo Konumlama yöntemi için elips tabanlı enerji hesaplama algoritması önerilmiştir. Özü parçacık süzgecine dayanan KU-MCK bir konumlama yöntemidir ve konumlamanın alt problemlerini (pozisyon takibi, global konumlama ve kaçırılmış robot) çözebilir. KU-MCK yöntemi enerji ızgaralarını...

This paper deals with the whole body motion control problem of humanoid robots by using automatic and bilateral control methods. Advanced motion controllers are proposed so that human daily life activities, such as walking on an uneven terrain and contacting an unknown object, can be performed. It is shown that the uncertainty of environmental impe...

The Simultaneous Localization and Mapping (SLAM) problem, which emerged in the last quarter of the century, has been adapted for territorial, naval and aerial platforms starting from the year of 2000's and some parametric filter approaches such as Kalman Filter based Extended Kalman Filter and Distributed Kalman Filter, the stateestimation methods...

This paper presents an application of a robust control method, the sliding mode control, to an irreducibly simple model of passive dynamic walking known as the simplest walking model. Although, the simplest walking model is well studied with indirect actuation methods, such as gravity power or toe off impulse, its capability to begin to walk from d...

In this paper, we present an enhanced loop closure method∗ based on image-to-image matching relies on quantized local Zernike moments. In contradistinction to the previous methods, our approach uses additional depth information to extract Zernike moments in local manner. These moments are used to represent holistic shape information inside the imag...

In this paper, the dynamic model of the Thomas-K biped robot, which was built at Ohnishi laboratory in Keio University, is derived, and a new efficient dynamic simulator is proposed. Although the dynamic model of bipedal locomotion is considered in this paper, the proposed model can be easily implemented any kind of floating point base robotic syst...

Simultaneous Localization and Mapping (SLAM) is a good choice for UAV navigation when both UAV’s position and region map are not known. Due to nonlinearity of kinematic equations of a UAV, Extended Kalman Filter (EKF) and Unscented Kalman Filter (UKF) are employed. In this study, EKF and UKF based A-SLAM concepts are discussed in details by present...

In this paper, a six-dimensional (6D) Simultaneous Localization and Mapping (SLAM) based on novel Linear Regression Kalman Filter (LRKF), called Smart Sampling Kalman Filter (S2KF), is proposed. While the conventional feature based SLAM methods use point features as landmarks, only a few take the advantage of geometric information like corners, edg...

Simultaneously Localization and Mapping (SLAM) problem requires a sophisticated scan matching algorithm, in which two consecutive point clouds belonging to highly correlated scene are registered by finding the rigid body transformation parameters when an initial relative pose estimate is available. A well-known scan matching method is the Iterative...

In this paper, three intelligent system methods namely Artificial Neural Network (ANN), Support Vector Machine (SVM) and Adaptive Neuro Fuzzy Inference Systems (ANFIS), are implemented to solve the inverse kinematics problem of the industrial robot arms. The main advantages of the intelligent system based solutions in the robot kinematics are that...

This paper introduces a novel image description technique that aims at appearance based loop closure detection for mobile robotics applications. This technique relies on the local evaluation of the Zernike Moments. Binary patterns, which are referred to as Local Zernike Moment (LZM) patterns, are extracted from images, and these binary patterns are...

In this paper, a novel method of extracting 3D planar features from laser range data (LiDAR) and its adaptation to outdoor SLAM using respective extended Kalman filter (EKF) and unscented Kalman filter (UKF) is proposed. Firstly, the feature extraction from 3D LiDAR data using a probabilistic plane extraction method and the merging procedure is exp...

This paper represents an approach to deal with graph-based map building by clustering the map features. the study will give an intuition about the sparsification of the map features using graph trees. Brief Survey and detailed examination of the subject is also given in the Methodology section. The study is concluded with simulation results and dis...

In this paper, inverse differential kinematic modeling is performed for a 7-DOF (Degrees of Freedom) redundant robot arm. Two intelligent identification methods, namely Artificial Neural Networks (ANN) and Support Vector Regression (SVR) are used for modeling. The main strengths of SVR over ANN are that it doesn't get stuck at local minima and it h...

In this paper, a novel method extracting 3D planar features from laser range data (LiDAR) and its adaptation to outdoor SLAM using respective Extended Kalman Filter (EKF) and Unscented Kalman Filter (UKF) is proposed. The paper is mainly divided into two parts such that the feature extraction algorithm and its application to SLAM problem are given....

This paper presents a dedicated approach to detect loop closures using visually salient patches. We introduce a novel, energy maximization based saliency detection technique which has been used for unsupervised landmark extraction. We explain how to learn the extracted landmarks on-the-fly and re-identify them. Furthermore, we describe the sparse l...

This paper presents an approach to detect visually salient patches in order to use them for visual place recognition. We formulate the saliency detection problem as an optimization problem, and define an energy function which describes the distinctiveness of a given image patch. We employ a Branch & Bound based search technique to efficiently find...

We present a new formulation method to solve the kinematic problem of multiarm robot systems. Our major aims were to formulize the kinematic problem in a compact closed form and avoid singularity problems in the inverse kinematic solution. The new formulation method is based on screw theory and quaternion algebra. Screw theory is an effective way t...

Simultaneous Localization and Map (SLAM) building problem has vital importance for fully autonomous systems in partly or fully Global Navigation Satellite Systems (GNSS) denied environments. For LiDAR systems, there are two different ways to deal with SLAM problems. They are graph representation based SLAM methods depending on mostly scan matching...

In this paper, a fast and robust feature based scan matching algorithm for LiDAR systems, especially dedicated to outdoor SLAM applications, is introduced. There are large numbers of variants of scan matching algorithms, and they are mostly based on matching of the whole or randomly sampled points. However, this study shows that the sampling strate...

In this paper, we compare three inverse kinematic formulation methods for the serial industrial robot manipulators. All formulation methods are based on screw theory. Screw theory is an effective way to establish a global description of rigid body and avoids singularities due to the use of the local coordinates. In these three formulation methods,...

Differential kinematic is one of the most important solution methods in robot kinematics. The main advantage of the differential kinematic method is that it can be easily implemented any kind of mechanisms. Also, an accurate and efficient kinematic based trajectory tracking application can be easily implemented by using this method. In differential...

Scan matching plays a significant role for 3D simultaneously localization and mapping (SLAM). Before applying the SLAM methods, two 3D data which belong to highly correlated scene has to be registered by finding the correct transformation. In this paper, we introduce a multi-layered (ML) extension of 3D Normal Distribution Transform based scan matc...

In this paper, motion equations for the synchro-drive robot Nomad 200 are solved by using Linde Buzo Gray (LBG) clustering neural networks. The trajectories of the Nomad 200 are assumed to be composed of straight line segments and curves. The structure of the curves is determined by only two parameters, turn angle and translational velocity in the...

This paper compares three inverse kinematic formulation methods for industrial robot manipulators. All formulation methods are based on screw theory. Screw theory is an effective way to establish a global description of rigid body and avoids singularities due to the use of the local coordinates. In these three formulation methods, two of them use q...

In this paper, we introduce a fast and robust scan matching method that combines the Multi-Layered Normal Distributions Transform (ML-NDT) and a feature extraction algorithm into a single framework. This is achieved by first applying the conventional NDT generation process to the reference scan, and the plane segments are extracted with the help of...

In this paper we present a singularity free trajectory tracking method for the cooperative working of multi-arm robot manipulators. It is based on an inverse kinematic transformation which determines the manipulator's joint angles corresponding to the end-effector trajectory given in the task space. The kinematic problem of multi-arm robot system i...

In this paper we present a kinematic based trajectory tracking application of redundant planar robot arm by using support vector machine method (SVM). The main advantages of using the proposed method are that, it does not suffer from singularity that is the main problem of redundancy in robot kinematics and better results for the kinematic model of...

Differential kinematic has a wide range application area in robot kinematics. The main advantage of the differential kinematic is that it can be easily implemented any kind of mechanisms. In differential kinematic method, Jacobian is used as a mapping operator in the velocity space. The joint velocities are required to be integrated to obtain the p...

Normal Distribution Transform (NDT) is an alternative scan matching approach to the well-known Iterative Closest Point (ICP) algorithm. NDT provides superior properties over ICP for large scale and outdoor SLAM since it represents the surface in a special compact form, and it is more robust in noisy environment. The main bottleneck of the NDT algor...

Underactuation may arise when a manipulator includes at least one passive joint. Free-flying platforms fall under passive systems since they can be considered as linked to a fixed base by 6-d.o.f. free joints with no friction. Dynamics of underactuated cooperating manipulators have become a bigger challenge when underactuation is encountered by the...

Bu çalışmada quadrotorun durumsal ve hover kontrolleri üzerinde durulmuştur. Klasik PD kontrol, ters dinamik kontrol, geri adımlamalı kontrol ve kayma kipli kontrol teknikleri doğrusal olmayan sistem için benzetim çalışmasında matematiksel modeline; deneysel çalışmada ise quadrotor platformuna uygulanmıştır. Bahsi geçen kontrol teknikleri bilgisaya...

In this article, artificial potentials approach is used at localization of the mobile vehicles in wireless sensor netwoks with hop-count method. For a mobile vehicle which travels in a WSN, to find a better route two common principle can be considered. One of them is hop-count and the other one is artificial potentilals. Both of them provide the mo...

A new inverse kinematic solution for serial robot manipulators is represented in this paper. Major aims of this paper are to obtain singularity avoiding inverse kinematic solutions and formulize kinematic problems in a compact closed form. Our solution method is based on screw theory and it uses quaternions as a screw motion operator. Screw theory...

In this paper we present a new formulation method to solve kinematic problem of serial robot manipulators. In this method our major aims are to formulize inverse kinematic problem in a compact closed form and to avoid singularity problem. This formulation is based on screw theory with dual - quaternion. Compared with other methods, screw theory met...

This paper presents an artificial emotional-cognitive system-based autonomous robot control architecture for a four-wheel driven and four-wheel steered mobile robot. Discrete stochastic state-space mathematical model is considered for behavioral and emotional transition processes of the autonomous mobile robot in the dynamic realistic environment....

This study includes altitude stabilization, hovering control any desired position and attitude control of quadrotor. Classically PD controller derived and applied to this system. Inverse dynamic control, feedback linearization control and sliding mode control methods have used to derive as nonlinear controllers. Linear and nonlinear control techniq...

This paper proposes to generate potential fields for navigation task of unmanned aerial vehicles (UAVs) which have fuzzy logic- (FL-)based autonomous flight controls. Three FL modules are developed under the navigation system for the control of the altitude, the speed and the heading, through which the global position of vehicle is controlled. A po...

Simultaneous Localization and Mapping (SLAM) using for the mobile robot navigation has two main problems. First problem is the computational complexity due to the growing state vector with the added landmark in the environment. Second problem is data association which matches the observations and landmarks in the state vector. In this study, we com...

Simultaneous localization and mapping (SLAM) for the mobile robot navigation has two main problems. The first problem is the computational complexity due to the growing state vector with the added landmark in the environment. The second problem is the data association which matches the observations and landmarks in the state vector. In this study,...

In this study, three types of gait generation methods in Quadruped walking are compared using simulation software such as ADAMS and Matlab/Simulink. Stability and straight path following performance of these three types is simulated and third type of gait generation method (Trotting) is found considerably well suited for practical point of view.

Integrated optimum design of structures and control systems is studied by using H 2 and H¥ H_{\infty } robust control formulations. It is derived that conventional simultaneous optimization approach by using these robust control laws can be approximated by a decoupled optimization approach in which the structures are optimized by shaping the struct...

As a recent trend in robotic research, legged robots gained importance since they are capable of performing vast maneuver abilities on rough terrain. Especially in case of planetary exploration, legged robots seem to offer the most suitable mechanism in order to accomplish any given mission. Therefore, this paper is aimed at introducing the develop...

In this study, behavior generation and self-learning paradigms are investigated for the real-time applications of multi-goal mobile robot tasks. The method is capable to generate new behaviors and it combines them in order to achieve multi goal tasks. The proposed method is composed from three layers: Behavior Generating Module, Coordination Level...

Formation graphs are widely used in multi vehicle decentralized formation control area. They provide a robust and scalable control approach and tools for designing stable systems. However, current methods cannot guarantee the uniqueness of formations for every communication scheme and resulting formations depend on initial conditions. In this artic...

In this work, decentralized formation control of a multi vehicle system is investigated. Each vehicle model considers kinematic constraints of differential drives which is a principal approach for various application for mobile robotics in 2D space. A virtual leader is assigned to navigate the whole cluster in a certain formation via predefined pat...

In this work, decentralized formation control of a multi vehicle system is investigated. Each vehicle is modeled as a point mass agent moving in 2D space. A virtual leader is used for navigation. Each vehicle produces its own control signal via communication with other vehicles and interactions with virtual leader and the obstacles around. These in...

In this study, behavioral system based robot control architecture is built up for a four-wheel driven and four-wheel steered mobile robot. Behavioral system is determined as evolutionary neural-fuzzy inference system for behavior generation and self-learning processes in the general robot control architecture. The kinematics and dynamic model of th...

This study proposes a new map building method for a mobile robot operating in an environment with obstacles by fusing sensor data. Required information for a map designing is supplied by fusion of different sensor data using the sequential principal component (SPC) method. We discuss mathematical and experimental issues of the method by comparing a...

This paper summarizes mechanical and electrical design of a unique mobile manipulator. Mechanical design is based on the idea of increasing capabilities of Mitsubishi PA-10 robot arm effectively and safely. A large number of sensors in different types and the mechanical design of the steering of each wheel require a reliable design and implementati...

This paper presents artificial emotional system based autonomous robot control architecture. Hidden Markov model developed as mathematical background for stochastic emotional and behavior transitions. Motivation module of architecture considered as behavioral gain effect generator for achieving multi-objective robot tasks. According to emotional an...

Using the method known as Weingarten map, instantaneous center of rotation (ICR) of a four-wheel-drive & four-wheel-steer (4WD/4WS) mechanism is obtained for a predefined path. Kinematical model is obtained based on multiple manipulators with constraints on a common base approach

In this study, we have developed a novel method to obtain high resolution images using an ordinary digital camera. Using successively taken images, our fusion algorithm has a profound effect in the quality of the image which contains richer independent pixels than the originals do. This method, which aims to increase the spatial resolution by addin...

Kinematically deficient manipulators are those that have fewer degrees of freedom than necessary to achieve any admissible configuration in their operational space. When multiple manipulators, some or all of which are kinematically deficient, cooperate to perform a common task, the constrained forces at the contact points cannot be solved directly...

In this study, a new approach in Hardware-In-the-Loop Simulation (HILS) is introduced as an education tool in robotics, mechatronics and control. The paper discusses the development and utilization of HILS specifically in the instruction of control and design aspects of on-site and remote robotics courses. A HIL simulator differs from computer simu...

In this study, state observation in positioning systems is discussed. A dynamical friction model, also called an elastoplastic model, describing basic friction phenomena such as stick-slip dynamics, presliding motion, the Stribeck effect, etc., is included in the positioning system model. A Luenberger-type state observer is presented and developed...

Direct model reference adaptive control (DMRAC) is the state of the art algorithm with very powerful properties including robustness with respect to unmodeled dynamics and ease of implementation even to very complex systems such as highly nonlinear MIMO plants. The motivation behind the research explained in this paper is to emphasize these propert...

This paper presents an analytical dynamic model of a four-wheel full-suspension vehicle using 24 independent dof. The methodology presented herein is capable of simulating vehicle dynamics on any terrain so long as it is smooth enough that tires can remain in contact. Given the steering torque, driving torque and terrain structure, the forward dyna...

Two-wheeled cart falls under kinematically deficient manipulator when considered from cooperating manipulator approach. Kinematically deficient manipulators are those that have fewer degrees of freedom than necessary to achieve any admissible configuration in their operational space. When multiple manipulators, some or all of which are kinematicall...

A novel methodology is presented for a practical problem of balancing a round object about its contact point posing pure rolling constraint at the tip of a redundant manipulator. Two-layer controller, the objective of the first of which is to balance the object as long as the manipulator stays in a singularity-free predefined task-space, is designe...

This article proposes a navigation technique based on fuzzy maps of the environment for real-time applications. Particularly choosing the right operator plays important role in obtaining good results rapidly and accurately for different kind of environments. Mainly, A* algorithm is used for navigating the mobile robot in the fuzzy mapped environmen...

This study describes a generation of globally time optimal trajectories for a mobile robot in predefined environment. The primary task in the study is to apply Differential Evolution (DE) method for definition of globally time-optimal trajectories under environmental and dynamical constraints. The planned trajectories are composed of line segments...

This paper presents dynamical modeling of topologically stacked structure of general underactuated mechanisms. Underactuation may arise when a manipulator includes at least one passive joint which is either a free joint where torque propagating along the axis of rotation is only due to friction, or a flexible joint which has passive elements introd...

in this study, integrated optimum design of structures and control systems is studied by using reduced order models. The structures and controllers are optimized simultaneously and successively. Since the degree-of-freedom (DOF) for structures is very large in practice, model order reduction techniques have to be employed at every controller design...

Underactuation may arise when a manipulator includes at least one passive joint which is either a free joint where torque propagating along the axis of rotation is only due to friction, or a flexible joint which has passive elements introducing stiffness and damping. In this regard, free flying platform can be considered as linked to a fixed base b...

This article compares Dempster Shafer's evidence methods' and fuzzy union operators' accuracy and speed criteria for real-time map building process. For real-time applications, it's very important to choose the right operator which can give good results rapidly for different kind of environments. In this study, several fuzzy union techniques are us...

Underactuation may arise when a manipulator includes at least one passive joint which is either a free joint where torque propagating along the axis of rotation is only due to friction, or a flexible joint which has passive elements introducing stiffness and damping. In this regard, free flying platform can be considered as linked to a fixed base b...

An evolutionary technique with a Fuzzy Inference System (FIS) is offered for planning time-optimal trajectories on a predefined Visibility Graph Method Dijkstra (VGM-D) path of a Nomad 200 mobile robot (MR). First of all, the segmented trajectory is generated by the VGM-D algorithm. Line and curve segments are the components of the trajectory. The...

This paper describes a complete approach for localization and path selection of any vehicle like a mobile robot to achieve any planetary exploration missions. In this study, localization process was realized on a mobile robot, Nomad 200, using its odometry and gyro measurements. These sensors information was integrated, by extended Kalman Filter (E...

In this study, given the topological structure, a three dimensional view of a working zone is constructed and analysed using a computer. The topological data is assumed to be present in a numerical format. Then, according to this data, a 3-D shape of the land is represented and viewed from different angles using a mouse or joystick. Alternative pat...