Publikační činnost Katedry robotiky / Publications of Department of Robotics (354)

Permanent URI for this collectionhttp://hdl.handle.net/10084/64802

Kolekce obsahuje bibliografické záznamy publikační činnosti (článků) akademických pracovníků Katedry robotiky (354)v časopisech registrovaných ve Web of Science od roku 2003 po současnost.
Do kolekce jsou zařazeny:
a) publikace, u nichž je v originálních dokumentech jako působiště autora (adresa) uvedena Vysoká škola báňská-Technická univerzita Ostrava (VŠB-TUO),
b) publikace, u nichž v originálních dokumentech není v adrese VŠB-TUO uvedena, ale autoři prokazatelně v době jejich zpracování a uveřejnění působili na VŠB-TUO.

Bibliografické záznamy byly původně vytvořeny v kolekci Publikační činnost akademických pracovníků VŠB-TUO, která sleduje publikování akademických pracovníků od roku 1990.

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Now showing 1 - 20 out of 66 results

Pneumatic bellows actuated parallel platform control with adjustable stiffness using a hybrid feed-forward and variable gain integral controller
(MDPI, 2023) Varga, Martin; Virgala, Ivan; Kelemen, Michal; Miková, Ľubica; Bobovský, Zdenko; Sinčák, Peter Ján; Merva, Tomáš
Redundant cascade manipulators actuated by pneumatic bellows actuators are passively compliant, rugged and dexterous, making them exceptionally well suited for application in agricul ture. Unfortunately, the bellows are notoriously difficult to precisely position. This paper presents a novel control algorithm for the control of a parallel platform actuated by pneumatic bellows, which serves as a module of a cascade manipulator. The algorithm combines a feed-forward controller and a variable-gain I-controller. The mathematical model of the module, which serves as the feed-forward controller, was created by applying two simple regression steps on experimentally acquired data. The gain of the I-controller is linearly dependent on the total reference error, thereby addressing the prevalent problem of “a slow response or excessive overshoot”, which, in the described case, the sim ple combination of a feed-forward and constant-gain I-controller tends to suffer from. The proposed algorithm was experimentally verified and its performance was compared with two controllers: an ANFIS controller and a constant gain PID controller. The proposed controller has outperformed the PID controller in the three calculated criteria: IAE, ISE and ITAE by more than 40%. The controller was also tested under dynamic loading conditions, showing promising results.
Design for low thermal conductivity and low vibrational impact without efflorescence of the composite bricks developed by waste plastic resin/fly ash/glass powder/gypsum
(Springer Nature, 2023) Singh, Aditya; Srivastava, Ashish Kumar; Kumar, Ajay; Gautam, Preeti
The growth of different sectors in developing countries requires a tremendous amount of energy, making energy an important factor leading to environmental and economic concerns toward energy saving. A total of 33% of the energy consumed comes from buildings, and 50% of this energy is lost via the walls. As a result, the intended thermal comfort criteria and the properties of the building envelope determine the total energy consumption of a material. A lower thermal conductivity rating can help to reduce this temperature loss even more. Therefore, it was intended in the research initiatives to create walling material, such as bricks, with low thermal conductivity without efflorescence. The ability of bricks to absorb the vibration helps them to better sustain under the seismic load. The composite brick of a dimensional size of 190 × 90 × 90 mm is developed with fly ash, polymer, glass powder, and gypsum (CaSO4.2H2O). The designed brick contains fly ash as the matrix material, plastic waste such as HDPE and PP resin as the binder, glass powder as reinforced, and gypsum as the nanofiller. Thermal conductivity decreases from 0.23 − 0.15 W/mk as the polymeric concentration increases in the designed sample by 30%, 35%, and 40% polymer. On analyzing the DSC curve the degradation temperature is found to be 123.64 and 139.58 °C, 125.92 and 144.64 °C, 127.50 and 153.07 °C respectively, for 30%, 35%, and 40% of the polymer corresponding to endothermic and exothermic reactions with enthalpy 4.4808 J/g and 2.2012 J/g, 4.5976 J/g, and 2.31487 J/g, 4.6859 and 2.4337 J/g respectively. Introducing the plastic content in the designed sample caused a significant decrease in thermal conductivity and improved the resilience properties against earthquakes to bear more impact load and developed stress to the structure.
The calibration process and setting of image brightness to achieve optimum strain measurement accuracy using stereo-camera digital image correlation
(MDPI, 2023) Hagara, Martin; Huňady, Róbert; Lengvarský, Pavol; Vocetka, Michal; Palička, Peter
Combining the drilling method with the digital image correlation (DIC) method is becoming more common to speed up the measurement and evaluate the strains relieved at several locations. However, to obtain the most accurate results, it is necessary to be aware of the influence of possible aspects that could adversely affect the results of the strain/stress analysis carried out using DIC. The paper describes several analyses to assess the influence of the 3D DIC system’s calibration procedure for strain/stress analysis of the specimen with a hole loaded with four different levels of tensile force. In addition, the paper also deals with the analysis of the influence of the image brightness, which was modified by changing the exposure time of the cameras. Based on the results of strain/stress analyses performed on small areas (approx. 25 × 25 mm) of a specimen with a hole by a stereo-camera DIC system, it can be concluded that both analysed factors can negatively influence the results. The most accurate results are ensured using the calibration target of very high manufacturing precision sized similarly to the field of view observed in correlation mode. The optimal image brightness is adjusted when the mean grey value of the image is from the range of 56 up to 171 with as evenly distributed image point intensities as possible.
Hierarchical real-time optimal planning of collision-free trajectories of collaborative robots
(Springer Nature, 2023) Lukáš, Dalibor; Kot, Tomáš
In collaborative robotics the manipulator trajectory has to be planned to avoid collisions, yet in real-time. In this paper we pose the problem as minimization of a quadratic functional among piecewise linear trajectories in the angular (joint) space. The minimization is subjected to novel nonlinear inequality constraints that simplify the original non-penetration constraints to become cheap to evaluate in real time while still preserving collision-avoidance. The very first and most critical step of the computation is to find an initial trajectory that is free of collisions. To that goal we minimize a weighted sum of the violated constraints until they become feasible or a maximal number of steps is reached. Sometimes an incremental growing of the obstacle helps. By incremental growing we mean that we sequentially solve auxiliary subproblems with obstacles growing from ground or falling from top and use as the initial trajectory the one optimized in the previous step. The initial trajectory is then optimized while preserving feasibility at each step. We solve a sequence of simple-bound constrained quadratic programming problems formulated in the dual space of Lagrange multipliers, which are related to the original linearized inequality constraints that are active or close-to-active. Finally, we refine the trajectory parameterization and repeat the optimization, which we refer to as an hierarchical approach, until an overall prescribed time limit, being well below a second, is reached.
Implementation of an embedded system into the Internet of Robotic Things
(MDPI, 2023) Krejčí, Jakub; Babiuch, Marek; Babjak, Ján; Suder, Jiří; Wierbica, Rostislav
The article describes the use of embedded systems in the Industrial Internet of Things and its benefits for industrial robots. For this purpose, the article presents a case study, which deals with an embedded system using an advanced microcontroller designed to be placed directly on the robot. The proposed system is being used to collect information about industrial robot parameters that impact its behavior and its long-term condition. The device measures the robot’s surroundings parameters and its vibrations while working. Besides that, it also has an enormous potential to collect other parameters such as air pollution or humidity. The collected data are stored on the cloud platform and processed and analysed. The embedded system proposed in this article is conceived to be small and mobile, as it is a wireless system that can be easily applied to any industrial robot.
Camera arrangement optimization for workspace monitoring in human-robot collaboration
(MDPI, 2023) Oščádal, Petr; Kot, Tomáš; Spurný, Tomáš; Suder, Jiří; Vocetka, Michal; Dobeš, Libor; Bobovský, Zdenko
Human-robot interaction is becoming an integral part of practice. There is a greater emphasis on safety in workplaces where a robot may bump into a worker. In practice, there are solutions that control the robot based on the potential energy in a collision or a robot re-planning the straight-line trajectory. However, a sensor system must be designed to detect obstacles across the human-robot shared workspace. So far, there is no procedure that engineers can follow in practice to deploy sensors ideally. We come up with the idea of classifying the space as an importance index, which determines what part of the workspace sensors should sense to ensure ideal obstacle sensing. Then, the ideal camera positions can be automatically found according to this classified map. Based on the experiment, the coverage of the important volume by the calculated camera position in the workspace was found to be on average 37% greater compared to a camera placed intuitively by test subjects. Using two cameras at the workplace, the calculated positions were 27% more effective than the subjects' camera positions. Furthermore, for three cameras, the calculated positions were 13% better than the subjects' camera positions, with a total coverage of more than 99% of the classified map.
Using elastic bands for collision avoidance in collaborative robotics
(IEEE, 2022) Kot, Tomáš; Wierbica, Rostislav; Oščádal, Petr; Spurný, Tomáš; Bobovský, Zdenko
The paper presents a new version of the existing elastic band algorithm used for path finding, with application in the field of collaborative robotics and point-to-point movements. The algorithm places control points on the path and dynamically modifies the position of these control points in reaction to any obstacles located or moving in the workspace. The control points are updated in the robot space (TCP space), obstacles are represented by a set of grid-aligned voxels acquired by a camera system. Repulsive forces are created between the obstacles and the robot body (represented by a set of points covering evenly the surface of individual links) and transferred to the locations of the elastic band control points. The method is computationally effective and provides a smooth and length-optimal path while considering collisions in a more accurate manner than traditional usage of simple bounding volumes. The dynamic iterative updating of elastic band provides a clear principle for modification of the trajectory even close to the actual location of the robot as it is following the trajectory. The algorithm is verified on a set of practical experiments made on a physical UR3 robot with simulated obstacles, and the results are also compared to other commonly used methods for dynamic obstacle avoidance.
Upgrade of biaxial mechatronic testing machine for cruciform specimens and verification by FEM analysis
(MDPI, 2022) Miková, Ľubica; Prada, Erik; Kelemen, Michal; Krys, Václav; Mykhailyshyn, Roman; Sinčák, Peter Ján; Merva, Tomáš; Leštach, Lukáš
This article deals with the modernization of an existing loading system for the analysis of elastic-plastic properties of sheet metals in plane stress. The identification of the beginning of plastic deformation of sheet metal in plane strain is important in the cold pressing of sheet metal and in the assessment of the load capacity of thin-walled structures in the automotive and aerospace industry. The design of the control structure of the hydraulic part of the loading system for cross testing was carried out to automatize the whole process of experimental evaluation. For this purpose, proportional pressure-reducing valves together with control electronics were designed. Thus, the loading system is a control system for which a control algorithm has been designed and implemented on a PC. A computer simulation was performed to verify the functionality of the load system. An FEM simulation was performed to verify the correctness of the proposed numerical models and to confirm the experimental results. A numerical nonlinear model of the selected material was applied for the specification of plastic deformations. From the results, it is possible to state the appropriateness of the used models as well as the appropriateness of using modernized equipment for subsequent analysis of the plastic deformation of cruciform specimens.
Generating synthetic depth image dataset for industrial applications of hand localization
(IEEE, 2022) Vysocký, Aleš; Grushko, Stefan; Spurný, Tomáš; Pastor, Robert; Kot, Tomáš
In this paper, we focus on the problem of applying domain randomization to produce synthetic datasets for training depth image segmentation models for the task of hand localization. We provide new synthetic datasets for industrial environments suitable for various hand tracking applications, as well as ready-to-use pre-trained models. The presented datasets are analyzed to evaluate the characteristics of these datasets that affect the generalizability of the trained models, and recommendations are given for adapting the simulation environment to achieve satisfactory results when creating datasets for specialized applications. Our approach is not limited by the shortcomings of standard analytical methods, such as color, specific gestures, or hand orientation. The models in this paper were trained solely on a synthetic dataset and were never trained on real camera images; nevertheless, we demonstrate that our most diverse datasets allow the models to achieve up to 90% accuracy. The proposed hand localization system is designed for industrial applications where the operator shares the workspace with the robot.
Research and development of a software tool for parametric modeling of robotized workplaces
(MM Science, 2022) Boleslavský, Adam; Mihola, Milan; Wierbica, Rostislav; Bém, Jan; Spurný, Tomáš
Designing a robotic workplace is a time and knowledge intensive process. It requires systems engineers who specialise in the design of this type of workplace and have the appropriate know-how in this area. Due to the time-consuming nature and the small number of experts, a small number of solution options are often created, from which the most suitable one is subsequently developed. The aim of the development was to create a tool that would simplify the design of robotic workplaces. The result is a software tool integrated into the SolidWorks CAD system. The tool uses a database of models. The connection between the developed software tool and the database is realized through the API of the SolidWorks CAD system. Thanks to this tool, it is possible to simplify and speed up the work of workplace design. More variant solutions can be developed and overall better results can be achieved.
Automation of design of robotic arm
(MM Science, 2022) Mihola, Milan; Zeman, Zdeněk; Boleslavský, Adam; Bém, Jan; Pastor, Robert; Fojtík, David
Robotic arms are complex mechatronic systems. Therefore, their design requires knowledge and experience from various technical fields, such as mechanics, electrical engineering, electronics or control. From the view of the requirements placed on developers, the design of robotic arms is one of the more complex tasks. Unfortunately, there is a lack of necessary specialists in this field of technology. Therefore, ways are sought to help existing specialists in their work and, simultaneously, reduce the time needed to design the required equipment. At the same time, there are also sought ways to open the way to this issue for developers who do not yet have enough experience.For this reason, algorithms and development tools have been developed to significantly simplify and reduce the time required to design robotic arms and simultaneously automate as much of this process as possible. The aim is to shorten the design time and achieve better results than in the case of designs according to classical procedures.
Biped robot with unconventional kinematics
(MM Science, 2022) Virgala, Ivan; Kelemen, Michal; Kelemenová, Tatiana; Miková, Ľubica; Prada, Erik; Grushko, Stefan; Varga, Martin; Sinčák, Peter Ján; Merva, Tomáš; Bobovský, Zdenko
The article deals with the design of a robot with an unconventional kinematic structure, which is able to vertically stabilize the position of the robot base for the placement of sensors and handling superstructures. The robot concept was designed to have as few actuators as possible. The robot's kinematics was solved for the purpose of simulating the robot's movement and implementation into the robot's control system.
Multirepresentations and multiconstraints approach to the numerical synthesis of serial kinematic structures of manipulators
(IEEE, 2022) Huczala, Daniel; Kot, Tomáš; Pfurner, Martin; Krys, Václav; Bobovský, Zdenko
This paper presents a set of algorithms for the synthesis of kinematic structures of serial manipulators using multiple constraint formulation and provides a performance comparison of different kinematic representations, the Denavit-Hartenberg notation, the Product of Exponentials (screws), and Roll-Pitch-Yaw angles with translation parameters. Synthesis is performed for five given tasks, and both revolute and prismatic joints can be synthesized. Two different non-linear programming optimization algorithms were used to support the findings. The results are compared and discussed. Data show that the choice of the constraint design method has a significant impact on the success rate of optimization convergence. The choice of representation has a lower impact on convergence, but there are differences in the optimization time and the length of the designed manipulators. Furthermore, the best results are obtained when multiple methodologies are used in combination. An arbitrary manipulator was designed and assembled based on a trajectory in the collision environment to demonstrate the advantages of the proposed methodology. The input/output data and synthesis methodology algorithms are provided through an open repository.
Distributed camera subsystem for obstacle detection
(MDPI, 2022) Oščádal, Petr; Spurný, Tomáš; Kot, Tomáš; Grushko, Stefan; Suder, Jiří; Heczko, Dominik; Novák, Petr; Bobovský, Zdenko
This work focuses on improving a camera system for sensing a workspace in which dynamic obstacles need to be detected. The currently available state-of-the-art solution (MoveIt!) processes data in a centralized manner from cameras that have to be registered before the system starts. Our solution enables distributed data processing and dynamic change in the number of sensors at runtime. The distributed camera data processing is implemented using a dedicated control unit on which the filtering is performed by comparing the real and expected depth images. Measurements of the processing speed of all sensor data into a global voxel map were compared between the centralized system (MoveIt!) and the new distributed system as part of a performance benchmark. The distributed system is more flexible in terms of sensitivity to a number of cameras, better framerate stability and the possibility of changing the camera number on the go. The effects of voxel grid size and camera resolution were also compared during the benchmark, where the distributed system showed better results. Finally, the overhead of data transmission in the network was discussed where the distributed system is considerably more efficient. The decentralized system proves to be faster by 38.7% with one camera and 71.5% with four cameras.
Knowledge-based automated mechanical design of a robot manipulator
(MDPI, 2022) Pastor, Robert; Mihola, Milan; Zeman, Zdeněk; Boleslavský, Adam
Design methods have been improving with an increasing level of algorithmic support for some time. The most recent advances include generative design and various optimization methods. However, the automated design tools are often focused on a single stage of the design process, for example, kinematics design, mechanical topology, or drive selection. In this paper, we show the whole design process of a robotic manipulator in an automated workflow. The method consisted of two main parts: a genetic optimization of the kinematic structure and an iterative automated CAD design. The method was then applied to a case study in which a manipulator with five degrees of freedom for a handling task was designed.
Automation of partial tasks in the design of robotic arms
(MM Science, 2022) Zeman, Zdeněk; Mihola, Milan; Suder, Jiří; Boleslavský, Adam
The design of robotic arms is a demanding process, especially in terms of the demands placed on developers' knowledge and experience and the time required for the design. Therefore, the development aimed to create procedures for possible automation of some of the individual tasks of the robotic arm design process, which are further applied in the development of a software tool for the automation of partial tasks in the design of robotic arms RobotDesigner. The benefits and functions of RobotDesigner are demonstrated in the example of optimization of a simple manipulator with 5 degrees of freedom for a given manipulation task. The optimization results show that the use of this software tool significantly speeds up and streamlines the sub-tasks of design and optimization of arms. By using iterative processes and artificial intelligence, using similar software tools and connecting them to CAD systems, it will not only be possible in the future to fully automate the robot arm design process but also to generate and compare different structures and design solutions to find the most optimal for the task, which the robot will perform.
Finding the optimal pose of 2D LLT sensors to improve object pose estimation
(MDPI, 2022) Heczko, Dominik; Oščádal, Petr; Kot, Tomáš; Boleslavský, Adam; Krys, Václav; Bém, Jan; Virgala, Ivan; Bobovský, Zdenko
In this paper, we examine a method for improving pose estimation by correctly positioning the sensors relative to the scanned object. Three objects made of different materials and using different manufacturing technologies were selected for the experiment. To collect input data for orientation estimation, a simulation environment was created where each object was scanned at different poses. A simulation model of the laser line triangulation sensor was created for scanning, and the optical surface properties of the scanned objects were set to simulate real scanning conditions. The simulation was verified on a real system using the UR10e robot to rotate and move the object. The presented results show that the simulation matches the real measurements and that the appropriate placement of the sensors has improved the orientation estimation.
Optimization of a truss structure used to design of the manipulator arm from a set of components
(MDPI, 2021) Rojíček, Jaroslav; Paška, Zbyněk; Fusek, Martin; Bobovský, Zdenko; Sapietová, Alžbeta; Mostýn, Vladimír; Ličková, Dagmar
The design of a manipulator arm, which is built from a construction kit, is presented in this article. The procedure is based on the results of the discrete optimization of a truss structure and its application to a simple component system (assuming a predefined shape and material of components). A genetic algorithm is used to optimize the truss structure, and the results of the solution are verified on a simple task used in literature (the code was written in the Python language). The construction kit was inspired by Merkur(R), and the article proposes several components with different shapes and materials. The construction kit and the optimization of the truss structure were used to design the manipulator arm. The truss topology has been predefined with respect to the construction set. The finite element method (software ANSYS(R)) was used to analyze the components (shell elements) and truss structures (linear analysis, buckling analysis, etc.). To validate the presented approach, the arm designed by topological optimization was used. The comparison shows that the use of components may be an alternative to topology optimization and additive manufacturing. The next step will be the modification of the presented method in order to minimize the differences between the simplified task used for optimization (truss structure-rod element) and the simulation composed of components (components assembly-shell element).
Research and development of a knowledge-based design system for designing selected elements of mechatronic devices
(MM Science, 2021) Mihola, Milan; Zeman, Zdeněk; Fojtík, David
The design of mechatronic devices is a demanding process not only in terms of the time required but also of the demands placed on the knowledge and experience of development workers. The aim of this research and development was to create suitable procedures, algorithms, and databases of 3D models, with the help of which could this process be significantly shortened and simplified. The results of the development are a software tool for the design of electric drive units, procedures for creating 3D models with the possibility of using the SolidWorks software API, methods for automating the creation of assemblies of 3D models and a description of the knowledge database in which various data and algorithms are stored. The benefits of the proposed procedures, the Drive Picker software tool, and the knowledge database, are demonstrated on the design of a robotic arm with 5 degrees of freedom. Despite the complexity of the preparation of documents needed, it turns out that the chosen approach can significantly speed up and simplify the design of mechatronic devices.
Analysis of increasing the friction force of the robot jaws by adding 3D printed flexible inserts
(MM Science, 2021) Suder, Jiří; Kot, Tomáš; Panec, Alan; Vocetka, Michal
3D printing technology plays a key role in the production of prototypes and final functional parts. The ability to produce almost any shape using this technology in combination with lightweight materials is often used to minimise the weight of the designed components. However, for some applications, such as robot gripper jaws, conventional most commonly used materials, such as PLA, may be unsuitable due to their low coefficient of friction on the material of the manipulated object, which in some cases may cause the object to slip in the robot jaws. This article describes a technical problem from practice, where a manipulated object made of steel material slipped in the printed PLA jaws of the robot during its working cycle. This work is devoted to increasing the friction force of the robot jaws by adding 3D printed soft inserts. Two insert surface shapes made of two flexible materials TPU 30D and TPE 88 are tested. The increase in friction force is measured on a measuring device with an industrial robot and a force measuring sensor. The most suitable type of inserts and material is then tested on a collaborative robot at its required working cycle. The results of this experiment are intended to help designers as a source of information or inspiration in designing similar applications.

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