#$%^&*AU2020217318A120200827.pdf#####ROBOTIC SURGICAL ASSEMBLIES ABSTRACT A surgical assembly for use with and for selective connection to a robotic arm includes an electromechanical instrument and an instrument drive unit. The instrument drive unit includes a motor and a feedback assembly. The motor is configured to effect rotation of the electromechanical instrument. The feedback assembly includes control circuitry and first and second annular members. The first annular member has a surface feature projecting therefrom. The second annular member is disposed adjacent the first annular member and has a first surface feature projecting therefrom, circumferentially aligned with the surface feature of the first annular member. The control circuitry is configured to determine an amount the surgical instrument rotates based on the surface feature of the first annular member engaging the surface feature of the second annular member.
