In rock excavation processes, hydraulic rotary-percussive drilling is used for drilling and blasting in both surface and underground drilling operations. A hydraulic percussive drilling system is composed of percussion, rotation, feed and flushing functions.

Percussion function produces fast stress waves that travel through the drill rod to the rock. Stress waves should be effectively transmitted to the rock meanwhile minimizing reflective forces.

The interaction between four different functions as well as rock conditions affect drilling efficiency. This project aims for developing adaptive drilling control for changing rock conditions.