The disclosure is directed to a medical robotic system and method for releasably securing a medical instrument over a modular support assembly that is further removably coupled to the manipulating arm via an intermediate fastening component. The medical instrument is configured for delivery through a small percutaneous penetration in a patient as it slides over the modular support assembly, independent of the manipulating arm. The robotic system further includes a simplified draping mechanism including covering the manipulating arm up to the fastening component thereby obviating the need for extensive sterile drape that extends all over the arm up to the support interface and the cannula holding assembly in existing art. Advantageously, the present invention allows for a quick and simple installation while allowing for free rotary motion of the support assembly.
