A computer-assisted medical system includes a display unit configured to provide images to an operator of the display unit, a headrest configured to receive a mechanical input provided by a head of the operator in mechanical contact with the headrest, a headrest sensor interfacing with the headrest and configured to provide sensor signals based on the mechanical input, and a controller. The controller includes a computer processor, and is configured to process the sensor signals to obtain a driving input, drive, by the driving input, a virtual mass to obtain a simulated virtual mass movement, and cause movement of the headrest, the movement of the headrest tracking the virtual mass movement.