Dynamics and Control of the Bucket-Wheel Excavator: Part I — Dynamic Modeling of Bucket-Wheel Boom

Bucket-Wheel excavators (BWE) represent a specific type of complex machine system used in mining technology. During operation, the system is exposed to a number of external forces and disturbances like digging resistances on the Bucket-Wheel that cause transverse, longitudinal, and torsional vibrations. All vibrations will affect to normal working conditions, operational effectiveness, and may under specific conditions also effect the stability of the BWE. To increase working conditions advanced control systems can be applied controlling the dynamics, especially induced structural vibrations. In order to analyze and synthesize a controller for the above mentioned system, adequate modeling to describe the dynamical behavior of the system under real operating conditions is necessary. In a previous investigation, it was assumed that the Bucket-Wheel boom can be modeled as a flexible beam using the Euler-Bernoulli beam theory. Additionally it is assumed that the boom is attached to the excavator turning platform. The nonlinear modeling of the three-dimensional elastic boom considering the elasticity of suspending cables and also couplings resulting from geometrical nonlinear deformations is presented. Here the known modeling approach of higher order is used and extended to model the Bucket-Wheel boom of a Bucket-Wheel-Excavator including guided rotating motion in combination with digging resistance forces. The dynamic phenomena resulting from the higher-order modeling including higher-order geometrical couplings as well as the external excitations on the dynamic behavior of the Bucket-Wheel boom are analyzed in detail. Intensive simulation studies are realized demonstrating the effect of higher-order couplings as well as resulting destabilizing effects from the modeling.