Liebherr has rolled out the "VarioTronic" system for its LB series rotary drilling rigs, moving away from traditional hydraulic pilot control to a fully electronic joystick interface. In sensitive urban environments, drilling near existing foundations or underground utilities requires extreme precision. Traditional hydraulic controls often suffer from "hysteresis"-a lag between the lever movement and the machine reaction-which can lead to over-crowding or sudden shock loads.
The VarioTronic system uses a pair of high-performance industrial computers to control the crowd winch (the up/down movement) and the rotary drive. A key engineering feature is the "Anti-Dive" logic. When drilling through unstable soil layers (e.g., loose gravel or sand), the weight of the Kelly bar can cause the drilling tool to plunge uncontrollably. The VarioTronic system monitors the speed of the Kelly bar extension using laser sensors. If the bar accelerates faster than the commanded speed, the system instantly applies the crowd winch brake and reduces the crowd force, preventing the tool from diving into the soft ground.
Additionally, the system features a "Continuous Casing Driving" mode. This automatically synchronizes the rotation of the casing rotator with the drilling tool. This eliminates the need for the operator to manually balance two separate joystick movements, ensuring that the casing is always advanced at the same rate as the drill bit. This automation significantly improves verticality control in mixed ground conditions.
