Control of the main working axes of bucket wheel excavators according to the criterion of desired capacity

The bucket wheel excavator is basic mining machine used on open pit mines with a continuous excavation process for soft and medium-hard materials. The increase in the need for ever greater quantities of excavated material has led to excavators being constructed today with a daily production capacity greater than 200,000 m
³
. Aside from the time and capacity availability of the excavators, to achieve efficient production, the manner in which they are controlled is also of great significance. The analysis of the technology for excavating massifs, as well as the structure and geometry of excavators, has led to the greatest number of applied solutions for control of excavators being through automatic operation: n
o
/cos and P=const. Due to the non-homogenous structure of material and the inconsistent and unpredictable geometry of the excavated block, the aforementioned methods do not provide the necessary efficiency for the operation of the excavator. The development of systems for measuring the volume flow of material and their application on excavators makes it possible for the measurement results to be used not only for statistical analysis, but also to develop algorithms for control of excavators. The location where the measurement system is installed complicates the use of its measurement results. Specifically, the information on the instantaneous production which the control system receives from the measurement system is delayed by the amount of time it takes the excavated material to travel from the bucket wheel to the location where its volume is measured (one of the conveyors on the excavator). In this work we will present the algorithm for control of a bucket wheel excavator according to the criterion of desired capacity, where the results of the system for measuring volume flow are used as feedback information on the capacity. The results of measurements performed on the terrain verify the control strategy, which is developed and tested based on mathematical model of bucket wheel excavator presented in the paper.