CONSTRUCTION AND TESTING OF THE MEASUREMENT SYSTEM FOR EXCAVATOR PRODUCTIVITY

Abstract

Hydraulic excavator is one of the most used machines in mining, construction and geotechnics. Monitoring its productivity can gain benefits like savings in fuel consumption and maintenance, cost optimization of working parameters and higher working efficiency. Measurement system for such purpose can be complex and expensive, requires special equipment from manufacturer and does not exist as out of the box solution that would measure working parameters such as bucket trajectory, digging energy, digging force etc. Measuring system was designed to monitor productivity and gather working parameters. It consists of three pressure transmitters for measuring cylinder pressures, three draw wire sensors for cylinder elongations, one inertial measurement unit for measurement of swing angle and one logger unit for data acquisition and storage. Logger unit, equipped with SD card module and 12-bit AD converter, is based on Atmega328 microcontroller, which allows for usage of Arduino IDE and already developed libraries. The system was tested in a laboratory to determine its accuracy, resolution and usable sample rate. Cylinder pressure can be measured in range 0-500 bar with excellent accuracy of 0.026 % FSO and 0.15 bar resolution. Cylinder elongation can be measured in range 0-2300 mm with accuracy of 0.26 % FSO and 0.58 mm resolution. Swing angle measurement accuracy is 1.5° per circle. Usable sample rate of the system is found to be 39 Hz-588 Hz, depending on the logger executing code.