The article considers the problem of position-force control of robot movement with a force feedback sensor in the mode of contact with a free-formed surface. The surface is assumed to be rough; the robot, according to the technological task, moves with a certain speed along the surface and maintains the predetermined level of contact force. In this case the surface roughness may cause the excitation oscillation of the robot close to resonance. The article shows in what case this effect is possible and how to control the vibration of the robot. We made a comparative analysis of the vibration state of the robot with a hard and active mount of the sensor to the robot arm. It is shown that the active mounting of the force sensor can significantly reduce the level of robot arm vibration. The article investigates the possibilities of further signal feedback using the accelerometer mounted on the robot arm, and the dynamic absorbing effect with active mounting of the force sensor.