An Automatic Procedure for Overheated Idler Detection in Belt Conveyors Using Fusion of Infrared and RGB Images Acquired during UGV Robot Inspection

Complex mechanical systems used in the mining industry for efficient raw materials extraction require proper maintenance. Especially in a deep underground mine, the regular inspection of machines operating in extremely harsh conditions is challenging, thus, monitoring systems and autonomous inspection robots are becoming more and more popular. In the paper, it is proposed to use a mobile unmanned ground vehicle (UGV) platform equipped with various data acquisition systems for supporting inspection procedures. Although maintenance staff with appropriate experience are able to identify problems almost immediately, due to mentioned harsh conditions such as temperature, humidity, poisonous gas risk, etc., their presence in dangerous areas is limited. Thus, it is recommended to use inspection robots collecting data and appropriate algorithms for their processing. In this paper, the authors propose red-green-blue (RGB) and infrared (IR) image fusion to detect overheated idlers. An original procedure for image processing is proposed, that exploits some characteristic features of conveyors to pre-process the RGB image to minimize non-informative components in the pictures collected by the robot. Then, the authors use this result for IR image processing to improve SNR and finally detect hot spots in IR image. The experiments have been performed on real conveyors operating in industrial conditions.

Research on Segmented Belt Acceleration Curve Based on Automated Mechanical Transmission

An automated mechanical transmission (AMT) is proposed as a new soft starter for medium-scale belt conveyors in this paper. The AMT is used to start the belt conveyor and shift gears step by step to make the belt conveyor accelerate softly. Based on analyzing common soft-starting acceleration curves, a segmented belt acceleration curve is proposed as a new soft-starting acceleration curve. By analyzing the AMT soft-starting system, the system modeling is built and the AMT output shaft’s angular acceleration is proposed to be controlled to control the belt acceleration. The AMT soft-starting simulation model is established in the environment of AMESim, and simulation results of the soft-starting process from the first to eighth gear positions are given. The main parameter curves of the AMT soft-starting system including the belt, driving pulley, and AMT output shaft are analyzed. The simulation model can indicate the viscoelastic property of the belt. The simulation results prove that the segmented belt acceleration is appropriate for a medium-scale belt conveyor and provide a theoretical and reasonable basis for using an AMT as a soft starter.

A Mobile Robot-Based System for Automatic Inspection of Belt Conveyors in Mining Industry

Mechanical systems (as belt conveyors) used in the mining industry, especially in deep underground mines, must be supervised on a regular basis. Unfortunately, they require high power and are spatially distributed over a large area. Till now, some elements of the conveyor (drive units) have been monitored 24 h/day using SCADA systems. The rest of the conveyor is inspected by maintenance staff. To minimize the presence of humans in harsh environments, we propose a mobile inspection platform based on autonomous UGV. It is equipped with various sensors, and in practice it is capable of collecting almost the same information as maintenance inspectors (RGB image, sound, gas sensor, etc.). Till now such experiments have been performed in the lab or in the mine, but the robot was controlled by the operator. In such a scenario the robot is able to record data, process them and detect, for example, an overheated idler. In this paper we will introduce the general concept of an automatic robot-based inspection for underground mining applications. A framework of how to deploy the inspection robot for automatic inspection (3D model of the tunnel, path planing, etc.) are defined and some first results from automatic inspection tested in lab conditions are presented. Differences between the planned and actual path are evaluated. We also point out some challenges for further research.

Modeling the system of a dovetailless asynchronous electric drive for conveyor mechanisms

The article considers a vector control system for asynchronous electric drive of belt conveyors, which uses an adaptive observer to control the speed of the electric drive. This allows you to increase the reliability and inter-interval maintenance of the electric drive. The requirements for the observer are determined, its mathematical description is made, and the law of adaptation is determined. In the Matlab Simulink package, a computer simulation of the proposed sensor-free control system is performed. A study of the robustness of the actuator in terms of the drift of the parameters of the motor when powered from the inverter, expressed by the integral criterion for parametric robustness. Based on the results obtained, a comparison is made and conclusions are drawn about the advantages and disadvantages of using an adaptive observer in comparison with other types of observers.

Coal Flowability Control on Preventing Spillage on Conveyor Belt Through Modeling and Simulation for Improving its Performance

Belt conveyors are generally used in mining plant areas, both surface and underground mines. The belt conveyor is mainly applied to transport the extracted bulk material from the mining site to delivery. The effectiveness of the extraction process depends on the reliability and durability of the conveyor belt system. In addition, conveyor performance is very important specially to control material flowability to prevent spills or other operational disturbances to optimize production throughput. However, the transfer chute and settling zone can cause some problems during the transfer process, such as material spills. This problem can reduce the function and performance of the conveyor belt. This paper discusses a design model to reduce the problem of spillage in the settling zone. The model was developed by compiling the previous defecting data from the durability of the conveyor system, then analyzed using Discrete Element Method (DEM) software and compared with bulk characteristics. The initial performance of certain conveyors is only capable of serving with an average production of 76% of the designed capacity while energy is consumed at full load. By applying the DEM simulation result, the blade gate can reduce the peak angle break in the depositional zone before exiting. After the analysis is completed using DEM, the conveyor increases the average production to 95% of the designed capacity. In conclusion, controlling the maximum belt load without spillage will reduce interruption on conveyor belt operation and maintenance costs therefore increase plant reliability and availability.

Conceptual solutions for control systems of differential tensioners for belt conveyors

Differential tensioning devices for belt conveyors in general and intermediate drives of extended conveyors in the form of closed traction loops are a new type of automatic tensioning devices that differ from other known designs by the presence of a stepwise discrete belt tension control system with separation of compensation functions for belt stretching under load and control of its tension during the operation of the conveyor in order to create optimal modes of belt loading. The article analyzes the well-known and practical concepts of belt conveyor control systems in general. The possibility of controlling the traction force realized by the intermediate belt drive by controlling the tension of the traction and load-carrying belts is shown. On the basis of the analysis, conceptual solutions for control systems for differential tensioning devices of belt conveyors are proposed with the possibility of both autonomous use and application in the structure of an integrated conveyor control system. Possible structures of linear parts of differential tensioning devices are presented, as well as options for the implementation of executive parts that directly move tensioning elements.

Simulation of unloading processes of short dump belt conveyors with speed control belt movement

Short dump belt conveyors are used to create bulk cargo both as an integral part of technological machines in the processing of building materials, and as vehicles in a chain of conveyors for transporting bulk cargo in accordance with the logistics of open warehouses. When implementing mechanization schemes for open warehouses, depending on the degree of variability of the cargo flow in the structures of such conveyors, drives can be used that allow regulating the speed of the belts, thereby controlling the productivity of the entire line. Often, short belt conveyors are not equipped with specialized unloading devices, which requires elaboration of the issues of movement of cargo particles during unloading, especially if the conveyor is operating in a production line. The article simulates the processes of unloading short dump belt conveyors when controlling the speed of the belt. Trajectories of movement of cargo particles for various parameters of conveyors are obtained: belt speed, conveyor tilt angle to the horizon, diameter of the unloading drum. It is shown that it is necessary to simulate unloading processes in all cases with belt speed control and conveyor operation without specialized unloading devices.

The D5 Silo of Manganese of the Lampreana (Zamora): History, Construction Characteristics and Technology

Spain’s National Network of Silos and Granaries building a total de 665 silos and 285 granaries. 20 different typologies of silos were built, highlighting type D over all of them with a total of 389 units. This typology prolonged its construction for 34 years, appearing several subtypes (D1, D2, D3 D4 y D5). The Manganese of the Lampreana silo (Zamora) is a D5 type silo with 3,350 t of storage capacity, distributed in 24 storage tanks called cells, built in 1968. Architecturally speaking it is a simple and powerful silo. It has a rectangular shape, made up of three rows of square cells, the outer rows of cells rested directly on the ground storey floor and the center row is raised. Front tower between two cells, being embedded between them in a central position, achieving a compact and robust volume. The structure is made up of reinforced concrete pillars at the corners of the cells and the cell walls of reinforce bricks. Technologically speaking it has many similarities with its predecessors, types A and B. Here the elevator receives the grain directly from the reception hopper raising wheat and emptying it onto an upper horizontal belt conveyor, where dampers motorized valves, it is distributed across other tubes to one of the three cells in each bay. The grain is unloaded onto lower horizontal belt conveyors lying at different heights. From there it is carried to a raised cell for bulk offloading onto a lorry.

Inspection Robotic UGV Platform and the Procedure for an Acoustic Signal-Based Fault Detection in Belt Conveyor Idler

Belt conveyors are commonly used for the transportation of bulk materials. The most characteristic design feature is the fact that thousands of idlers are supporting the moving belt. One of the critical elements of the idler is the rolling element bearing, which requires monitoring and diagnostics to prevent potential failure. Due to the number of idlers to be monitored, the size of the conveyor, and the risk of accident when dealing with rotating elements and moving belts, monitoring of all idlers (i.e., using vibration sensors) is impractical regarding scale and connectivity. Hence, an inspection robot is proposed to capture acoustic signals instead of vibrations commonly used in condition monitoring. Then, signal processing techniques are used for signal pre-processing and analysis to check the condition of the idler. It has been found that even if the damage signature is identifiable in the captured signal, it is hard to automatically detect the fault in some cases due to sound disturbances caused by contact of the belt joint and idler coating. Classical techniques based on impulsiveness may fail in such a case, moreover, they indicate damage even if idlers are in good condition. The application of the inspection robot can “replace” the classical measurement done by maintenance staff, which can improve the safety during the inspection. In this paper, the authors show that damage detection in bearings installed in belt conveyor idlers using acoustic signals is possible, even in the presence of a significant amount of background noise. Influence of the sound disturbance due to the belt joint can be minimized by appropriate signal processing methods.