Patent ID: 7984769

Claim:
A method for directional control of a rock-drilling machine, comprising: locating a drilling unit of the rock-drilling machine in a borehole, the drilling unit comprising at least a pilot drill bit or an underreamer drill bit; driving the drill bit(s) being by an electric motor via a gearbox; moving the drill bit(s) into a rock by a feeding rod extending from a feeding machine outside the borehole; pivoting the drill bit(s), gearbox and motor in a controlled manner about a steering axis which is approximately perpendicular to a centre axis of the feeding rod; monitoring a position of the drilling unit by a control system; and after monitoring the position, adjusting a rotational angle of the drilling unit about the centre axis of the feeding rod and an angle between a centre axis of the drill bit and the centre axis of the feeding rod in accordance with a desired value.