An ultrasonic surgical instrument for use with a surgical robot , the ultrasonic surgical instrument comprising: a housing configured to mount to a linkage of a surgical robot and defining a cavity ; an ultrasonic generator at least partially disposed within the cavity of the housing, wherein the ultrasonic generator is supported within the housing, wherein the ultrasonic generator includes a horn ; a waveguide assembly coupled to the ultrasonic generator and at least partially disposed within the cavity of the housing, characterised in that the waveguide assembly includes: a proximal connector and a waveguide extending from the proximal connector; a blade at a distal portion of the waveguide; an inner tube disposed over the waveguide; and a clamping member pivotally supported at a distal portion of the inner tube; a lead screw disposed within the housing, configured to engage an instrument drive unit, wherein the housing defines a longitudinal axis and wherein the lead screw defines an axis of rotation that is parallel to the longitudinal axis of the housing; and a drive rod disposed within the housing and configured to translate within the housing in response to rotation of the lead screw, the drive rod including: an engagement feature , configured to engage the lead screw; and a distal engagement feature engaged with the proximal connector to transition the clamping member, in response to translation of the drive rod, between an open position, wherein the clamping member is spaced apart from the blade, and a clamped position, wherein the clamping member is approximated with the blade. a housing configured to mount to a linkage of a surgical robot and defining a cavity ; an ultrasonic generator at least partially disposed within the cavity of the housing, wherein the ultrasonic generator is supported within the housing, wherein the ultrasonic generator includes a horn ; a waveguide assembly coupled to the ultrasonic generator and at least partially disposed within the cavity of the housing, characterised in that the waveguide assembly includes: a proximal connector and a waveguide extending from the proximal connector; a blade at a distal portion of the waveguide; an inner tube disposed over the waveguide; and a clamping member pivotally supported at a distal portion of the inner tube; a proximal connector and a waveguide extending from the proximal connector; a blade at a distal portion of the waveguide; an inner tube disposed over the waveguide; and a clamping member pivotally supported at a distal portion of the inner tube; a lead screw disposed within the housing, configured to engage an instrument drive unit, wherein the housing defines a longitudinal axis and wherein the lead screw defines an axis of rotation that is parallel to the longitudinal axis of the housing; and a drive rod disposed within the housing and configured to translate within the housing in response to rotation of the lead screw, the drive rod including: an engagement feature , configured to engage the lead screw; and a distal engagement feature engaged with the proximal connector to transition the clamping member, in response to translation of the drive rod, between an open position, wherein the clamping member is spaced apart from the blade, and a clamped position, wherein the clamping member is approximated with the blade. an engagement feature , configured to engage the lead screw; and a distal engagement feature engaged with the proximal connector to transition the clamping member, in response to translation of the drive rod, between an open position, wherein the clamping member is spaced apart from the blade, and a clamped position, wherein the clamping member is approximated with the blade. <EOS>