Ahmet Yazici

Eskisehir Osmangazi University | ESOGU · Department of Computer Engineering

Purpose This study aims to propose a novel method for the conflict detection and eradication of autonomous vehicles which has predetermined routes to establish multi pickup and delivery tasks according to task priorities and vehicle capacity status on each pickup and delivery nodes in assembly cells in the automotive production. Design/methodology...

Purpose Electrical motors are among the most widely used equipment components across many industries. Therefore, monitoring electrical motors for the early detection of faults is essential for uninterrupted production and can save time and money for manufacturers. Bearing faults are one of the most frequently encountered fault types in induction mo...

Early fault detection and real-time condition monitoring systems have become quite significant for today’s modern industrial systems. In a high volume of manufacturing facilities, fleets of equipment are expected to operate uninterrupted for days or weeks. Any unplanned interruptions to equipment uptime could jeopardize manufacturers’ cycle time, c...

The integration of Industry 4.0 concepts into today’s manufacturing settings has introduced new technology tools that have already started providing companies an increased level of efficiency in certain operations. Autonomous Transfer Vehicles (ATV) are one of these new tools that are popular in today’s manufacturing settings. As these tools become...

Deep learning (DL) techniques have been gaining ground for intelligent equipment/process fault diagnosis applications. However, employing DL methods for such applications comes with its technical challenges. The DL methods are utilized to extract features from raw data automatically, which leads up to its own complications in data preprocessing and...

In Industry 4.0 Resource Description Framework (RDF), a semantic data model can be used to solve challenges such as unique identification, data availability, and interoperability. In this study, an integration of environmental, mechanical, and software errors in a common language is proposed for an Autonomous Mobile Robot (AMR) application ta...

Autonomous Transfer Vehicles (ATVs) are becoming increasingly prevalent in intra logistics. Industry 4.0 is bringing us closer to the efficient routing and scheduling of autonomous multi robot systems which perform transportation tasks. In this study, an energy efficient routing and scheduling system is proposed to minimize the total energy that th...

Maintenance planning is critical for efficient operations of manufacturing systems. While unnecessary maintenance causes waste of money and time, skipping necessary maintenance can also cause unexpected down times in production. Predictive maintenance activities which focus on both detection and classification of equipment faults at an early stage...

Üretim ve bakım faaliyetlerinin birlikte çizelgelenmesi konusunda çalışmalar sanayide dijitalleşmenin artması ile son yirmi yılda artış göstermiştir. Üretimde çeşitli sebeplerden kaynaklı duruşlar planlanan üretim çizelgesinde sapmalara neden olmaktadır. Ortaya çıkan etkin olmayan süreler makine ve adam-saat cinsinden israfa yol açmaktadır. Burada...

Endüstriyel sistemlerdeki makine arızalarını önleyerek üretimde oluşabilecek kesintilerden kaçınmak ve ilgili maliyetleri azaltmak etkin bir bakım yönetimi ile mümkündür. Etkin bakım yönetimi önleyici, düzeltici ve kestirimci bakım stratejilerinin yönetilmesi faaliyetlerini içermektedir. Sensör ve bilgisayar teknolojisindeki son gelişmelerle kestir...

Endüstriyel sistemlerdeki makine arızalarını önleyerek üretimde oluşabilecek kesintilerden kaçınmak ve ilgili maliyetleri azaltmak etkin bir bakım yönetimi ile mümkündür. Etkin bakım yönetimi önleyici, düzeltici ve kestirimci bakım stratejilerinin yönetilmesi faaliyetlerini içermektedir. Sensör ve bilgisayar teknolojisindeki son gelişmelerle kestir...

Endüstriyel sistemlerdeki makine arızalarını önleyerek üretimde oluşabilecek kesintilerden kaçınmak ve ilgili maliyetleri azaltmak etkin bir bakım yönetimi ile mümkündür. Etkin bakım yönetimi önleyici, düzeltici ve kestirimci bakım stratejilerinin yönetilmesi faaliyetlerini içermektedir. Sensör ve bilgisayar teknolojisindeki son gelişmelerle kestir...

Endüstriyel sistemlerdeki makine arızalarını önleyerek üretimde oluşabilecek kesintilerden kaçınmak ve ilgili maliyetleri azaltmak etkin bir bakım yönetimi ile mümkündür. Etkin bakım yönetimi önleyici, düzeltici ve kestirimci bakım stratejilerinin yönetilmesi faaliyetlerini içermektedir. Sensör ve bilgisayar teknolojisindeki son gelişmelerle kestir...

Endüstriyel sistemlerdeki makine arızalarını önleyerek üretimde oluşabilecek kesintilerden kaçınmak ve ilgili maliyetleri azaltmak etkin bir bakım yönetimi ile mümkündür. Etkin bakım yönetimi önleyici, düzeltici ve kestirimci bakım stratejilerinin yönetilmesi faaliyetlerini içermektedir. Son yıllarda, bilgisayar ve iletişim teknolojisindeki gelişme...

Autonomous transfer vehicles (ATVs) can be considered as one of the critical components of context-aware structured smart factories in Industry 4.0 era. Conventional mapping methods such as grid maps can provide information for navigation, but they are not enough for complex environments that require interactions. On the other hand, high-definition...

Multi-robot route planning (MRRP) is required in many applications of autonomous robots. In the literature, different performance metrics such as time, distance, and energy were proposed for route planning of multi-robot teams. These metrics are essential for efficient operation of multi-robot team. Besides, reliability is very important for reduci...

Robotic systems are used many areas where it is dangerous or difficult for people to do. The importance of autonomous robots increased with the Industry 4.0, and the concept of reliability needed more attention for long term operability of robotic systems. In this study, reliability based task allocation analysis is performed for robots by using fu...

Robotik sistemler, insanların yapmasının tehlikeli veya zor olduğu birçok alanda kullanılmaktadır. Endüstri 4.0 ile birlikte, otonom robotların önemi artmış ve robotik sistemlerin daha uzun süre problemsiz çalışması için gerekli olan güvenilirlik vb. kavramlar öne çıkmıştır. Bu çalışmada, bulanık mantık kullanılarak robotlar arasındaki görev paylaş...

This paper proposes a collision warning system for railway vehicles to be used in non-signaled rail lines in Turkey. The system consists of vehicle control unit (VCU), RF communication unit, sensors and display unit. V2V(vehicle-to-vehicle) communication is used to exchange information among the vehicles. The V2V packet comprises the vehicle's trav...

Technological developments about robotic and programming have become indispensable part of our lives. Learning and improving these technologies which get in our lives quickly is very important in the age of the child. In this study, Interactive Serious Games with Visual Programming for Mobile Robot Learning (evacocuk) that is an educational game ha...

Smart phones are widely used in indoor positioning and navigation systems. Thus, it is important to know the relative position of the smart phone on the user while calculating position with RSS based systems. The accuracy of position will change within this scope. In this study, an intermediary solution is proposed to find the position of the smart...

Nowadays, robots have taken place of human beings in every area so the reliability of the robot has become important. Reliability analysis is applied to improve the reliability of imperfect robotic systems and to minimize the failures that may be occur in these systems. Overall reliability of the robot is obtained with applying the reliability anal...

The Presentation of "An Intelligent PID Tuning Method for an Autonomous Mobile Robot" In this study, a Best First Search (BFS) Based Intelligent PID Tuning Method is proposed for a mobile robot path tracking problem. BFS is an informed search strategy in Artificial Intelligence (AI). It has been used in many areas of intelligent systems. Here, it...

The Abstract of "An Intelligent PID Tuning Method for an Autonomous Mobile Robot" In this study, a Best First Search (BFS) Based Intelligent PID Tuning Method is proposed for a mobile robot path tracking problem. BFS is an informed search strategy in Artificial Intelligence (AI). It has been used in many areas of intelligent systems. Here, it is u...

The Presentation of "A Smooth Path Generation Approach for Sensor-based Coverage Path Planning" In this study, a path smoothing strategy is proposed for sensor-based coverage problems. Smooth paths are generated for the coverage problems considering mobile robot kinematics constraints. An open agent architecture-based control structure is used to...

Increasing elderly people population and people with disabilities constitute a huge demand for wheelchairs. Wheelchairs have an important role on improving the lives and mobilization of people with disabilities. Moreover, autonomous wheelchairs constitute a suitable research platform for academic and industrial researchers. In this study, Finite st...

Autonomous mobile vehicles are used in many applications to realize special tasks. These tasks involve obstacle avoidance, target reaching and/or tracking. Such vehicles include the use of artificial intelligence to assist the vehicle's operator. Fuzzy logic can be used in the design of an autonomous vehicle to improve the classical control mechani...

Autonomous mobile vehicles are used in many areas. These vehicles are supposed to realize correct robotic behaviors in respect of the application type. Classical robot control/decision mechanisms can give imperfect results due to sensor compensation errors or calculation costs. Fuzzy logic, in some cases, can be used to overcome these problems. In...

Nowadays, location based applications increasingly used in many areas. Although outdoor navigation software applications are mature and widely used, improvements are required for indoor navigation. The applications such as guidance of disabled people, applications for security, visitor tracking, address mapping, the organization of services, automa...

Nowadays, indoor and outdoor location-aware applications has been become increasingly widespread. Location information for outdoor applications is obtained from well-known systems such as GPS and GLONASS. Although there are several systems for indoor localization, there is not a consensus on them like the outdoor. In this study, several aspects of...

Localization plays an important role in many applications. One of the positioning systems developed for indoor environments is İÇKON that can calculate the position of an object at cm accuracy by using pure ultrasonic signals. In this study, the ICKON system is switched to wireless sensor network to reduce setup time, and a mobile application is de...

Multirobot sensor-based coverage path planning determines a tour for each robot in a team such that every point in a given workspace is covered by at least one robot using its sensors. In sensor-based coverage of narrow spaces, i.e., obstacles lie within the sensor range, a generalized Voronoi diagram (GVD)-based graph can be used to model the envi...

Mobile robots are increasingly used for servicelike applications in which the service points are known and the mobile robot starts from a starting location, visits all the service points requested and returns to the starting location. The tour construction problem in these applications can be treated as a Travelling Salesman Problem (TSP). Classica...

Localization plays an important role in many applications such as robotic, signal processing and sensor networks. In the previous study, an indoor positioning system (İCKON) was developed. The İCKON uses only ultrasonic signals to calculate the position of mobile unit at cm level accuracy. For this accuracy, transmitter positions must be known in a...

Sensor-based multi-robot coverage path planning problem is one of the challenging problems in managing flexible, computer-integrated, intelligent manufacturing systems. A novel pattern-based genetic algorithm is proposed for this problem. The area subject to coverage is modeled with disks representing the range of sensing devices. Then the problem...

Position measurement is one of the primal problems in wide range of applications such as air/land/marine vehicles tracking, automation systems, and equipment tracking in medical sector, robotics and sensor networks. Location information in outdoor application can be easily obtained from well-known systems such as GPS and GLONASS. Since GPS signal i...

A security-constrained power dispatch problem with non-convex cost function for a lossy electric power system area including limited energy supply thermal units fueled under a take-or-pay agreement is formulated. Then, an iterative solution method based on a modified subgradient algorithm based on feasible values and common pseudo scaling factor fo...

The real structured singular value (RSSV, or real μ) is a useful measure to analyze the robustness of linear systems subject to structured real parametric uncertainty, and surely a valuable design tool for the control systems engineers. We formulate the RSSV problem as a nonlinear programming problem and use a new computation technique, F-modified...

In this study, a smooth path planning approach is proposed and compared to path smoothing for an autonomous mobile robot. Classical start-goal oriented path planning algorithms find paths that do not consider robot kinematic constraints. These paths may have sharp turns at some intersections. When mobile robot follows such a path, it stops, reorien...

Localization is an important problem for robotics and mobile platforms. Although there is some globally accepted positioning systems (e.g., GPS, GLONASS) for outdoor environments, there is not such a system for indoor. In this study, an ultrasonic based positioning system (SESKON) is developed especially for indoor robotic applications. The SESKON...

In this study, a reference governor approach is proposed for path tracking of nonholonomic mobile robot considering prescribed constraints. The proposed approach is designed to minimize the tracking error with a desired speed while satisfying all other constraints such as bounds on linear and angular velocities, acceleration. This approach determin...

In this paper, a security constrained power dispatch problem for a lossy electric power system area including limited energy supply thermal units is modeled in such a way that the modified subgradient algorithm based on feasible values (F-MSG algorithm) can be used to solve it. This model considers bus voltage magnitudes and phase angles, off-nomin...

In this paper, the modified subgradient algorithm based on feasible values (F-MSG) is applied to a security constrained environmental/economic dispatch problem for a power system area including limited energy supply thermal units. A nonlinear programming model is set up for the problem solution. Power system transmission loss is inserted into this...

In this paper, a security constrained power dispatch problem for a lossy electric power system area including limited energy supply thermal units is modeled in such a way that the modified subgradient algorithm based on feasible values (F-MSG algorithm) can be used to solve it. This model considers bus voltage magnitudes and phase angles, off-nomin...

In this study, a Best First Search (BFS) Based Intelligent PID Tuning Method is proposed for a mobile robot path tracking problem. BFS is an informed search strategy in Artificial Intelligence (AI). It has been used in many areas of intelligent systems. Here, it is used to search values of both ultimate period and ultimate gain of Ziegler-Nichols (...

Multi-robot sensor-based coverage path planning requires every point given in the workspace has to be covered at least by a sensor of a robot in the robot team. In this study, a novel algorithm was proposed for the sensor-based coverage of narrow environments by considering energy capacities of the robots. For this purpose, the environment was mode...

Sensor-based coverage problems have many applications such as patrolling, search-rescue, and surveillance. Using multi-robot team increases efficiency by reducing completion time of a sensor-based coverage task. Robustness to robot failures is another advantage of using multiple robots for coverage. Although there are many works to increase the eff...

In this paper, a vector-projection-based algorithm is developed to detect obstacles in narrow environments. This algorithm can be used for especially sensor-based coverage problems. The algorithm distinguishes the obstacles from the walls around the robot. Sonar vectors are projected on the edge which the robot moves to detect the obstacles. After...

In this study, a novel dynamic path planning approach is proposed for multi-robot sensor-based coverage considering energy capacities of the mobile robots. The environment is assumed to be narrow and partially unknown. A Generalized Voronoi diagram-based network is used for the sensor-based coverage planning due to narrow nature of the environment....

In this study, a path smoothing strategy is proposed for sensor-based coverage problems. Smooth paths are generated for the coverage problems considering mobile robot kinematics constraints. An open agent architecture-based control structure is used to implement the proposed approach on real robots. The algorithm is coded with C++ and implemented o...

Minimizing the coverage task time is important for many sensor-based coverage applications. The completion time of a sensor-based coverage task is determined by the maximum time traveled by a robot in a mobile robot group. So the environment needs to be partitioned among robots considering their travel times. Most of the coverage algorithms results...

In this study, a novel sensor-based coverage algorithm is proposed for multi-robots considering energy capacities of the mobile robots. Firstly, the environment is modeled by a Generalized Voronoi diagram-based graph to guarantee complete sensor based coverage. Secondly, depending on required arc set, an initial complete coverage route is created b...

Multi-robot coverage path planning problems require every point in a given area to be covered by at least one member of the robot team using their sensors. For a time-efficient coverage, the environment needs to be partitioned among robots in a balanced manner. So the problem can be modeled as task assignment problem with load balancing. In this st...

Sensor-based mobile robot coverage path planning (MRCPP) problem is a challenging problem in robotic management. We here develop a genetic algorithm (GA) for MRCPP problems. The area subject to coverage is modeled with disks representing the range of sensing devices. Then the problem is defined as finding a path which runs through the center of eac...

Multi-robot systems have recently received a great deal of attention due to the ability to perform an assigned task in a more reliable, faster and cheaper way beyond what is possible with a single robot. However, they may have some drawbacks, such as obstruction among robots during a task. Non-intersecting tours are preferable for the robots to pre...

In this paper we provide an overview of the simulation and testing environments developed for the Ohio State Universitypsilas DARPA Urban Challenge vehicle OSU-ACT (Autonomous City Transport). These environments were used in the research and development process of the actual challenge vehicle, and also extended for classroom teaching purposes and f...

In this paper, a decentralized control is utilized for the traffic signal control problem using model predictive control. A point-queue model is used with red-green signal transition times. A traffic signal controller is designed to minimize the queue lengths with information from the adjacent intersections. After the signal controller gathers the...

Mobile robots are increasingly used in many areas. An optimum trajectory increases the effectiveness of a mobile robot. However, the environment may change dynamically which may require a real-time tour construction for the mobile robot.In this study, a heuristic-based TSP approach is applied to real-time dynamic tour construction problem for a mob...

This study proposed a traffic responsive urban traffic control system using RFID(radio frequency identification) technology to get traffic information. The proposed system is a decentralized control using model predictive control. The objective of the proposed system is to obtain traffic data using advanced technology for controlling the junctions'...

In this paper, a decentralized control is utilized for the traffic signal control problem using model predictive control. A point-queue model is used with red-green signal transition times. A traffic signal controller is designed to minimize the queue lengths with information from the adjacent intersections. After the signal controller gathers the...

A nonlinear programming approach for the inverted pendulum swing-up control is presented. Even though it is an energy-based method, it uses fundamentally different mathematical tools to achieve the swing-up goal. The control problem translated into nonlinear programming model with appropriate objective function and constraints. While the objective...

In this study, a vehicle routing problem-based approach is presented to construct non-intersecting routes for the members of a mobile robot team. It is assumed that each robot starts from a central location such as the charging point, completes its route and returns to the starting location. The proposed method consists of three algorithms: a sweep...

One of the main concerns in multi-robot applications is the effects of interactions among the robots on the total performance of the team. If the robots are assigned to spatially separate tasks, the negative impact of these interactions may be decreased. In this paper a VRP-based method is proposed to create non-intersecting routes for a team of ro...

A linear programming approach for computation of sliding-mode control inputs is proposed. The method is applied to a double-inverted pendulum system and it takes input and approaching rate constraints into account. The derivation procedure reveals that it is generalizable to a large class of dynamic systems and can take a more general set of constr...

A new approach to compute optimal forcing functions for nonlinear dynamic systems expressed by differential equations and stemming from the sliding mode control (SMC) problems is presented. SMC input achieves generation of a desired trajectory in two phases. In the first phase, the input is designed to steer the state of the nonlinear dynamic syste...

We treat the sliding mode control problem by formulating it as a two phase problem consisting of reaching and sliding phases. We show that such a problem can be formulated as bicriteria nonlinear programming problem by associating each of these phases with an appropriate objective function and constraints. We then scalarize this problem by taking w...

Acrobot, a planar two-link robot with an actuator only at its elbow, is a typical example for underactuated systems. We stabilize the Acrobot by using a linear quadratic controller with a fixed set of coefficients. The difficulty of the problem arises from the real uncertainties in its parameters. In the presence of real uncertainties, stabilizing...

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In this study, a navigation algorithm for a mobile robot has been developed using fuzzy logic methods. Only the starting and destination coordinates are specified and robot travels form the starting point to the destination without having a priori knowledge of the environment. Therefore, robot can also travel in dynamic environments. Robot uses son...

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We take a new look at the real structured singular value computation problem which is a popular tool for testing robustness of a system. Structured singular value computation is an NP hard problem and some software packages propose lower and upper bounds to it. The gap between the lower and upper bounds is large for many problems so that the benefi...

Robust stability analysis of inverted pendulum system with a fixed linear quadratic feedback is carried out using µ analysis tools. A mathematical model of inverted pendulum system is presented and linearized about the desired equilibrium point. A linear quadratic control feedback matrix is used in the configuration of the nominal inverted pendulum...

We design sliding mode controllers for nonlinear dynamic systems by using a nonlinear programming approach. We show that by appropriate selection of the objective function and the constraints, it is possible to obtain sliding mode controller parameters by solving a sequence of nonlinear programming prob- lems. These parameters determine the forcing...