A sensor-based robot control technique for handling non-contact/transitions in a partially unknown environment is presented. Desired contacts with the environment were handled by integrating proximity and force/torque sensing information to improve efficiency in terms of speed and safety. By detecting in advance the target surface to be reached, the algorithm plans the trajectory to impose a smooth velocity profile during the approach, as well as to maintain the impact forces at the desired level by means of force control. A smooth transition between free and constrained motion control was obtained by means of weight functions depending on the measured distance between the robot end-effector and the target to be reached. >