Petr Olivka

Calibration of Short Range 2D Laser Range Finder for 3D SLAM Usage

The laser range finder is one of the most essential sensors in the field of robotics. The laser range finder provides an accurate range measurement with high angular resolution. However, the short range scanners require an additional calibration to achieve the abovementioned accuracy. The calibration procedure described in this work provides an estimation of the internal parameters of the laser range finder without requiring any special three-dimensional targets. This work presents the use of a short range URG-04LX scanner for mapping purposes and describes its calibration. The precision of the calibration was checked in an environment with known ground truth values and the results were statistically evaluated. The benefits of the calibration are also demonstrated in the practical applications involving the segmentation of the environment. The proposed calibration method is complex and detects all major manufacturing inaccuracies. The procedure is suitable for easy integration into the current manufacturing process.

The Design of 3D Laser Range Finder for Robot Navigation and Mapping in Industrial Environment with Point Clouds Preprocessing

This article describes the design of 3D Laser range finder LRF for industrial and mine environment. The 3D LRF is designed for usage on middle size robots and can be used for environment mapping and navigation. The design reflects heavy and dirty working conditions in industrial environment and it is equipped by own methane sensor for usage in mine. The process of design started with definition of requirements, follows by dynamic analysis and selection of suitable parts. The housing is designed from stainless steel and it encloses all electrical and mechanical components. The internal control unit is designed to suit modern trends of fog computing. It is equipped with four cores ARM CPU and IMU and it is able to preprocess the acquired point clouds in real time.

Exploration Mobile Robot for Coal Mines

This paper describes a Main Control System (MCS) and 3D map subsystem of the mobile robot TELERESCUER for inspecting coal mine areas affected by catastrophic events. It is carried out in a framework of a EU programme of the Research Fund for Coal and Steel under the grant agreement No. RFCR-CT-2014-00002. The interesting problem is to applicate the very demanding safe requirements of ATEX on the design of the control system including its communication with other robot subsystems. Due to a very innovative and advanced HMI the system allows the rescuer to operate the robot as if he were at the very center point of the scene of the robot’s operation.6 This project is solved by consortium of: Silesian University of Technology (Poland), VSB – Technical University of Ostrava (Czech Republic), AITEMIN (Spain), SIMMERSION GMBH (Austria) and SKYTECH RESEARCH (Poland).

The Radio Direction Finding with Advantage of the Software Defined Radio

The radio-frequency engineering recently has gone through extensive development. Software-Defined Radio (SDR) plays an important role in this development, bringing new possibilities to radio-frequency engineering and enables us to look at existing radio technologies in a new, innovative way. One such technology is a Doppler antenna, which allows us to find the direction from which the radio signal of given frequency is being transmitted. The SDR allows us to design and construct a highly-simplified system based on the Doppler antenna array. This paper deals with the design and implementation of such system used for the localization using the Doppler effect and the tests of the designed Doppler antenna system.

Rendering of 3D Maps with Additional Information for Operator of a Coal Mine Mobile Robot

The paper focuses on visualization of point clouds made by a 3D scanner mounted on a mobile robot Telerescuer designed for reconnaissance of coal mines affected by a disaster. Briefly are described some algorithms used for point cloud pre-processing – voxelization for data reduction, outliers removing for filtering of erroneous data and smoothing for additional filtering of noise data. These algorithms are implemented in C++ using the Point Cloud Library.

EM410x RFID cloned card detection system

RFID tags are nowadays used for granting access to buildings, tracking goods, persons and animals, in electronic toll collection systems, mobile payments, and other application areas. The purpose of this paper is to propose a solution that is capable of detecting fake (cloned) low cost 125 kHz RFID tags. The paper is focusing on detecting clones and emulators of EM410x tags. The proposed method is based on modifying the RFID reader and exploiting the specific features and properties of the fake tags. The experiments performed with the RFID reader with the implementation of the proposed clone detection techniques have shown that it is possible to reliably detect the majority of the publicly available fake tags and emulators. Moreover, the reader is capable of deactivating some of the clone tags if necessary.

Neural Network Classification of SDR Signal Modulation

With the rising popularity of Software Defined Radios (SDR), there is a strong demand for automatic detection of the modulation type and signal parameters. Automatic modulation classification is an approach to identify the modulation type and its parameters such as the carrier frequency or symbol rate. In electronic warfare, it enables real-time signal interception and processing. In civil applications, it can be used, e.g., by the amateur radio operators to automatically set the transceiver to the appropriate modulation and communication protocol. This paper presents a modulation classification driven by a neural network. A set of signal features are provided as an input of the neural network. The paper discusses the relevance of different signal features and its impact on the success rate of the neural network classification. The proposed approach is tested on both artificial and real samples captured by the SDR.

Process of Point Clouds Merging for Mapping of a Robot’s Working Environment

The lidar is nowadays increasingly used in many robotic applications. Nevertheless the 3D lidars are still very expensive and their use on small robots is not economical. This article briefly introduces a construction of cheap 3D lidar for indoor usage based on the 2D laser range finder. Subsequently, this article introduces process of merging acquired point clouds. The every pair of neighboring point clouds is oriented in space to fit together in the best possible way. The result of this process is a 3D map of the robot working environment. This map can be segmented and further used for a navigation. In this way, it is also possible to map inaccessible and dangerous areas.

Connecting Household Weather Sensors to IoT World

As the Internet of Things applications become more widespread, we face the need to replace existing implementations with Internet-enabled sensors. However, these sensors often provide worse battery life, have higher costs per unit and are not backward-compatible with existing weather stations. This paper concentrates on the possibility of decoding the weather station data by a cheap device which would forward them to the Internet of Things frameworks. The basics steps of receiving and decoding of the wireless weather sensor data are discussed together with the common problems which are associated with their capture and processing.

Software Controlled High Efficient and Accurate Microstepping Unit for Embedded Systems

In this paper, we present a novel design of a microstepping control unit. The goal is to improve the efficiency and compactness of current control units. An effective hardware implementation based on a single microcontroller and L6202 is proposed. By performing the computation of the duty cycle inside the microcontroller PIC18F2455, we have achieved superior positioning accuracy. The unit is designed as a small module, suitable for embedded applications.