Sensor and Navigation Subsystem for Mobile Robot

Práce se zabývá návrhem senzorického a navigačního subsystému mobilního robotu. Cílem práce je navrhnout systém, který umožní mobilnímu robotu autonomní jízdu v předem definovaném prostředí s dynamicky se měnícími překážkami. Navrhovaný subsystém vychází z analýzy robotu, pro který je systém určený. Dále je provedena analýza prostředí, ve kterém se má robot pohybovat. Následně je vytvořen simulační model robotu s reálně nastavenými parametry vyplývajícími z detailního 3D modelu. Rovněž je vytvořen simulační model prostředí, které vyplývá z návrhu možných prostor katedry robotiky. Práce se dále zabývá rozšířením senzorického subsystému, který je rozdělen na detekci překážek a lokalizaci robotu. Data ze senzorů jsou dále zpracovávána pro výpočet aktuální polohy a vektoru pohybu do operátorem zadané pozice. Operátor nastavuje parametry robotu pomocí serveru, který komunikuje s robotem. Systém umožňuje řídit robot manuálně nebo automaticky.The thesis deals with the design of the sensory and navigation subsystem of the mobile robot. The aim of this work is to design a system that will enable the mobile robot to run autonomously in a predefined surroundings with dynamically changing obstacles. The proposed subsystem is based on the robot analysis for which the system is designed. Next was performed an analysis of the surroundings in which will the robot moves. Subsequently, a simulation model of the robot is created with the real parameters set from the detailed 3D model. Simulation model of the surroundings is also created. The thesis also deals with the extension of the sensor subsystem, which is divided into obstacle detection and robot localization. The sensor data is further processed to calculate the current position and motion vector into the operator-specified position. The operator sets the robot parameters using a server that communicates with the robot. The system allows the robot to be controlled manually or automatically.354 - Katedra robotikyvýborn

Design of the Robotic End-effector for Tightening Used in the Workplace with Collaborative Robot

Bakalářská práce se zabývá průzkumem trhu s efektory pro utahování šroubů na pracovišti se spolupracujícím robotem. Po stanovení základních požadavků, jsou navrženy dvě konstrukční řešení technologického efektoru. Vybraný konstrukční návrh je důkladně navržen a rozpracován z běžně dostupných komponentů a vyráběných dílů.This thesis deals with market research on effectors for tightening the screws used on the workplace with collaborative robots. After determining the basic requirements are proposed two design solutions. Optimal design solution is thoroughly developed and designed using commercially available components and special parts.354 - Katedra robotikyvýborn

Improved mutual understanding for human-robot collaboration: Combining human-aware motion planning with haptic feedback devices for communicating planned trajectory

In a collaborative scenario, the communication between humans and robots is a fundamental aspect to achieve good efficiency and ergonomics in the task execution. A lot of research has been made related to enabling a robot system to understand and predict human behaviour, allowing the robot to adapt its motion to avoid collisions with human workers. Assuming the production task has a high degree of variability, the robot's movements can be difficult to predict, leading to a feeling of anxiety in the worker when the robot changes its trajectory and approaches since the worker has no information about the planned movement of the robot. Additionally, without information about the robot's movement, the human worker cannot effectively plan own activity without forcing the robot to constantly replan its movement. We propose a novel approach to communicating the robot's intentions to a human worker. The improvement to the collaboration is presented by introducing haptic feedback devices, whose task is to notify the human worker about the currently planned robot's trajectory and changes in its status. In order to verify the effectiveness of the developed human-machine interface in the conditions of a shared collaborative workspace, a user study was designed and conducted among 16 participants, whose objective was to accurately recognise the goal position of the robot during its movement. Data collected during the experiment included both objective and subjective parameters. Statistically significant results of the experiment indicated that all the participants could improve their task completion time by over 45% and generally were more subjectively satisfied when completing the task with equipped haptic feedback devices. The results also suggest the usefulness of the developed notification system since it improved users' awareness about the motion plan of the robot.Web of Science2111art. no. 367

Initial estimation of kinematic structure of a robotic manipulator as an input for its synthesis

Researchers often deal with the synthesis of the kinematic structure of a robotic manipulator to determine the optimal manipulator for a given task. This approach can lower the cost of the manipulator and allow it to achieve poses that might be unreachable by universal manipulators in an existing constrained environment. Numerical methods are broadly used to find the optimum design but they often require an estimated initial kinematic structure as input, especially if local-optimum-search algorithms are used. This paper presents four different algorithms for such an estimation using the standard Denavit-Hartenberg convention. Two of the algorithms are able to reach a given position and the other two can reach both position and orientation using Bezier splines approximation and vector algebra. The results are demonstrated with three chosen example poses and are evaluated by measuring manipulability and the total link length of the final kinematic structures.Web of Science118art. no. 354

Increasing the reliability of data collection of laser line triangulation sensor by proper placement of the sensor

In this paper, we investigated the effect of the incidence angle of a laser ray on the reflected laser intensity. A dataset on this dependence is presented for materials usually used in the industry, such as transparent and non-transparent plastics and aluminum alloys with different surface roughness. The measurements have been performed with a laser line triangulation sensor and a UR10e robot. The presented results are proposing where to place the sensor relative to the scanned object, thus increasing the reliability of the sensor data collection.Web of Science218art. no. 289

Distributed camera subsystem for obstacle detection

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.Web of Science2212art. no. 458

Structural optimization method of a FinRay finger for the best wrapping of object

Soft gripping, in which the gripper adapts to differently shaped objects, is in great demand for use in unknown or dynamically changing environments and is one of the main research subjects in soft robotics. Several systems have already been created, one of which is a passive shape-adaptable finger based on the FinRay effect. The geometric shape of this finger ensures that the finger wraps around the object it grips. FinRay fingers have been studied in several studies, which have changed the internal structure and examined how gripping force's dependence on finger deformation changes. So far, however, no specific way has been determined to evaluate the proposed finger regarding its ability to wrap around the object. This work comes up with a new and simple method to evaluate the finger's wrapping around the object mathematically. Based on this evaluation method, several different patterns of the internal structure of FinRay fingers were tested. The fingers were first tested in a simulation program, which simulated a steel roller indentation with a diameter of 20 mm in the middle of the finger's contact surface. Based on the simulation results, selected types of structure were made by the Fused Filament Fabrication method from a flexible filament and tested on a real test rig to verify the results of the simulation and compare it with the real behaviour. According to the methodology used, the results show that the most suitable structure of the selected tested fingers from the point of view of wrapping the finger around the object is a structure without internal filling. Designers can simply use the new evaluation method to compare their designed finger variants and select the most suitable one according to the ability to wrap around the gripped object. They can also use graphs from this work's results and determine the finger's dimensions without internal filling according to the required forces and deflection.Web of Science119art. no. 385

Camera arrangement optimization for workspace monitoring in human-robot collaboration

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.Web of Science231art. no. 29

Optimizing a quadruped robot: a comparison of two methods

Robots that have been optimized in simulation often underperform in the real world in comparison to their simulated counterparts. This difference in performance is often called a reality-gap. In this paper, we use two methods, genetic algorithm and topology optimization, to optimize a quadruped robot. We look at the original and optimized robots' performance in simulation and reality and compare the results. Both methods show improvement in the robot's efficiency, however the topology optimization behaves in a more predictable manner and shows similar results in simulation and in real laboratory testing. Modifying robot morphology with a genetic algorithm, although less predictable, has a potential for more improvement in efficiency.Web of Science20214355434

Monitoring of shared workspace between human-cobot

Předkládaná disertační práce se zabývá snímáním pracovního prostoru robotizovaného pracoviště určeného pro spolupráci člověka a kolaborativního robotu (cobotu). V rámci průmyslu 4.0 dochází k velkému nárůstu nasazovaní kolaborativních robotů. I přestože jsou tyto roboty přizpůsobeny pro spolupráci a sdílení pracovního prostoru s člověkem, efektivita pracoviště není tak vysoká jako u standardních průmyslových robotů. Jelikož cobot vykonává svoji předdefinovanou úlohu bez ohledu na pracovníka a objektů v pracovišti, může dojít ke kolizi. Díky vlastnostem cobotů je pak takovýto náraz běžně bezpečný a nedojde ke zranění pracovníka nebo poškození zařízení. Nicméně důsledkem i drobné kolize je prodloužení pracovního cyklu pracoviště, kdy zpravidla dojde k nouzovému zastavení cobotu. Dostupné bezpečnostní prvky v dnešní době neumožňují snímat celé dynamicky se měnící prostředí robotizovaných pracovišť natolik, aby mohla být v reálném čase přeplánována trajektorie robotu, a tedy nedošlo ke kolizi mezi pracovníkem nebo objekty, které představují pro robot překážku. Úvodní část této práce se zabývá analýzou současného stavu problematiky 3D vidění, kalibrací, filtrací prostředí a optimalizací umístění kamer na pracovišti. Na základě stanovených cílů disertační práce jsou následně zkoumány možnosti zvýšení přesnosti odhadu polohy kamer v prostoru. Nově navržený 3D gridboard pro určování polohy kamer byl implementován na průmyslovou i servisní aplikaci. Aby bylo možné data z kamer efektivně využívat pro řídící systém manipulátoru, je dále vytvořená filtrační technologie, která umožňuje v reálném čase odstranit nepotřebná data a předávat jen nezbytně nutné informace pro nadřazený řídící systém. Pomocí distribuované struktury bylo docíleno snímání a filtrování sledovaného prostoru v reálném čase, bez ohledu na počet kamer v systému, aniž by se zpomalovala obnovovací frekvence scény. Dále byla stanovena metodika rozmístění kamer na pracovišti, aby bylo možné efektivně snímat nebezpečný prostor, ve kterém hrozí kolize s cobotem. Na závěr je tato problematika experimentálně ověřena a implementována do reálného řídícího systému pro vyhýbání se dynamickým překážkám.The dissertation deals with the monitoring of the workspace of a robotic workstation designed for collaboration between a human and a collaborative robot (cobot). There is a large increase in the deployment of collaborative robots within Industry 4.0. Even though these robots are adapted to collaborate and share workspace with humans, the efficiency of the workplace is not as high as that of standard industrial robots. Since the cobot performs its predefined task without regard to the worker and objects in the workspace, collisions can occur. Due to the characteristics of cobots, then, such a collision is normally safe and will not injure the worker or damage the equipment. However, the consequence of even a minor collision is extended work cycle of the workplace caused by an emergency stop of the cobot. The safety features available today do not allow sensing of the entire dynamically changing environment of robotic workplaces to such an extent that the robot trajectory can be re-planned in real time, and thus avoid collisions between the worker or objects. The introductory part of this thesis deals with the analysis of the current state of the art in 3D vision, calibration, environmental filtering, and optimization of camera placement in the workplace. Based on the stated objectives of the dissertation, the possibilities of improving the accuracy of estimating the position of cameras in space are then investigated. A newly designed 3D gridboard for camera positioning has been implemented on industrial and service applications. Furthermore, in order to use the camera data efficiently for the manipulator control system, a filtering technology is developed to remove unnecessary data in real time and to transmit only the necessary information to the higher-level control system. By using a distributed structure, real-time sensing and filtering of the monitored area was achieved, regardless of the number of cameras in the system, without slowing down the refresh rate of the scene. Furthermore, a methodology for deploying cameras in a workplace was established to effectively capture the hazardous area where a cobot collision is imminent. Finally, this issue is experimentally verified and implemented in a real control system for dynamic obstacle avoidance.354 - Katedra robotikyvyhově