Robotic surgical systems having a fixed roll insertion guide

A method of operating a robotic surgical system, comprising:

• positioning an instrument driver adjacent a patient, the instrument driver including:
• a body having a proximal end, a distal end, and defining a central aperture extending between the proximal and distal ends;
• an outer housing extending at least partially between the proximal and distal ends;
• a tool drive assembly provided at the proximal end and extending into the outer housing
• a stator gear arranged within the outer housing and fixed to the tool drive assembly;
• and
• a rotor gear engageable with the stator gear;
• coupling a surgical tool to the instrument driver at the proximal end, the surgical tool including:
• a drive housing having a first end, a second end, and a carriage movably mounted to the drive housing between the first and second ends, wherein the first end of the drive housing is releasably coupled to the tool drive assembly at the proximal end;
• and
• an elongate shaft extending from the carriage and penetrating the first end, the shaft having an end effector arranged at a distal end thereof, wherein the shaft and the end effector penetrate the instrument driver by extending through the central aperture;
• actuating a drive motor included in the instrument driver and operatively coupled to the tool drive assembly via the rotor gear and thereby rotating the tool drive assembly about the central axis relative to the outer housing;
• and
• rotating the surgical tool about the central axis as coupled to the tool drive assembly.