Mobile mapping technologies, based on techniques such as simultaneous localization and mapping (SLAM) and surface-from-motion (SfM), are being vigorously developed both in the scientific community and in industry. They are crucial concepts for automated 3D surveying and autonomous vehicles. For various applications, rotating multiline scanners, manufactured, for example, by Velodyne and Ouster, are utilized as the main sensor of the mapping hardware system. However, their principle of operation has a substantial drawback, as their scanning pattern creates natural gaps between the scanning lines. In some models, the vertical lidar field of view can also be severely limited. To overcome these issues, more sensors could be employed, which would significantly increase the cost of the mapping system. Instead, some investigators have added a tilting or rotating motor to the lidar. Although the effectiveness of such a solution is usually clearly visible, its impact on the quality of the acquired 3D data has not yet been investigated. This paper presents an adjustable mapping system, which allows for switching between a stable, tilting or fully rotating lidar position. A simple experiment in a building corridor was performed, simulating the conditions of a mobile robot passing through a narrow tunnel: a common setting for applications, such as mining surveying or industrial facility inspection. A SLAM algorithm is utilized to create a coherent 3D point cloud of the mapped corridor for three settings of the sensor movement. The extent of improvement in the 3D data quality when using the tilting and rotating lidar, compared to keeping a stable position, is quantified. Different metrics are proposed to account for different aspects of the 3D data quality, such as completeness, density and geometry coherence. The ability of SLAM algorithms to faithfully represent selected objects appearing in the mapped scene is also examined. The results show that the fully rotating solution is optimal in terms of most of the metrics analyzed. However, the improvement observed from a horizontally mounted sensor to a tilting sensor was the most significant.

Streszczenie The paper deals with mobile robots with special emphasis on walking robots. A review of applications of particular types of mobile robots in various applications has been carried out. The validity of the use of walking robots in inspection tasks has been analyzed. A list of commercially available solutions has been presented and their parameters compared. A concept of a miniature walking robot for inspection tasks requiring operation in a confined space has been proposed. The design of the prototype, the structural solutions used, the system diagram and the structure of the control algorithms are presented. Conclusions and observations on the design process are presented. A set of modifications and solutions enabling the application of the robot in real inspection conditions have been proposed. The validity of the presented concept has been analyzed.

The belt conveyors of high power are the main transport in the industry, especially for mining enterprises. Since the total length of conveyors in the mines reaches several kilometres, the inspection of all idlers in harsh conditions is a challenge for maintenance personnel because the jamming of supporting idlers with damaged bearings causes belt overheating and subsequent fire. Conveyor belt breaking is also a serious trouble during continuous operation. In this research, the authors based on preliminary measurements are aiming to show that fault detection in belt conveyor idlers is quite possible to be conducted using a single or multiple small-size IMU (or other type thin sensors) placed directly on the belt or inside it. The information available from the IMU sensor is discussed in this paper. Transient signals are associated with the sensor passing each idler. Some methods for signals processing and possible diagnostic features extraction are presented.