Patent ID: 8708058

Claim:
A method for controlling at least one drill parameter when drilling in rock with a rock drill, said rock drill comprising an impulse-generating device arranged to induce shock waves in a tool acting against the rock with a percussive force generated via a percussion pressure, a rotation-generating device arranged to supply a torque to an impact device with a rotation generated via a rotation pressure, and a pressurisable damping chamber arranged to at least partially regulate contact of the rock drill with the rock via a damping pressure in the damping chamber, wherein said method includes the steps of: determining a first parameter value (P 1 ) representing the damping pressure (D), determining a second parameter value (P 2 ) representing the rotation pressure (R) of the drill bit, determining a deviation (ΔR) between the above second parameter value and a rotation pressure reference value (Rref), maintaining or changing a damping pressure reference value (Dref, Dref 1 , Dref 2 ) in dependence on said deviation, and regulating the percussion pressure (S) based on a function of the first parameter value (P 1 ) and the damping pressure reference value.