A robotic surgical system configured for the articulation of a catheter comprises an input device, a control computer, and an instrument driver having at least one motor for displacing the pull-wire of a steerable catheter wherein the control computer is configured to determine the desired motor torque or tension of the pull-wire of a catheter based on user manipulation of the input device. The control computer is configured to output the desired motor torque or tension of the pull-wire to the instrument driver, whereby at least one motor of the instrument driver implements the desired motor torque to cause the desired pull-wire tension to articulate the distal tip of the catheter.
