Modellering av rotationssystem

Sammanfattning: This master thesis was conducted during the spring of 2014 at Atlas Copco Rock Drills AB in Örebro. The purpose of the thesis was to develop a simulation model of the rotation system for a hydraulic rock drill. In the future, the model will be used to investigate the phenomena called “jerky rotation”. In order to validate the simulation model a test bench was designed and tests were made. The main focus was to model the gerotor motor that is used to propel the rotation of the drill string. The model shows the pressure and flow variations that occur due to the geometry of the motor. Simple models of the rock and drill steel were developed to simulate the entire rock drill. Those models were also validated with test results. The results from the model of the motor are considered to be good enough to be used for future simulations of the rotation of the rock drill. However, in order to see the cause of “jerky rotation”, a better model of the hydraulic supply system for the gerotor is needed. A better model of the rock might also be needed.