An apparatus for operating on tissue, the apparatus comprising: (a) an end effector , wherein the end effector comprises an ultrasonic blade ; (b) a shaft assembly , wherein the end effector is disposed at a distal end of the shaft assembly, wherein the shaft assembly defines a longitudinal axis, wherein the shaft assembly includes an articulation section operable to deflect the end effector away from the longitudinal axis, wherein the articulation section comprises a first articulation band and a pair of ribbed bodies , wherein the first articulation band is apposed between the pair of ribbed bodies, and is translatable relative to the shaft assembly to deflect the end effector away from the longitudinal axis; and (c) an interface assembly , wherein the interface assembly is configured to drive the end effector, wherein the interface assembly comprises: (i) a base , wherein the base is configured to couple with a dock of a robotic control system , (ii) a plurality of drive shafts oriented perpendicular to the longitudinal axis, wherein a first drive shaft of the plurality of drive shafts is rotatable to translate the first articulation band, (iii) an eccentric cam secured to the first drive shaft, and (iv) a pivoting arm coupled with the first articulation band, wherein the eccentric cam is operable to drive the pivoting arm proximally in response to rotation of the first drive shaft, to thereby deflect the end effector away from the longitudinal axis. (a) an end effector , wherein the end effector comprises an ultrasonic blade ; (b) a shaft assembly , wherein the end effector is disposed at a distal end of the shaft assembly, wherein the shaft assembly defines a longitudinal axis, wherein the shaft assembly includes an articulation section operable to deflect the end effector away from the longitudinal axis, wherein the articulation section comprises a first articulation band and a pair of ribbed bodies , wherein the first articulation band is apposed between the pair of ribbed bodies, and is translatable relative to the shaft assembly to deflect the end effector away from the longitudinal axis; and (c) an interface assembly , wherein the interface assembly is configured to drive the end effector, wherein the interface assembly comprises: (i) a base , wherein the base is configured to couple with a dock of a robotic control system , (ii) a plurality of drive shafts oriented perpendicular to the longitudinal axis, wherein a first drive shaft of the plurality of drive shafts is rotatable to translate the first articulation band, (iii) an eccentric cam secured to the first drive shaft, and (iv) a pivoting arm coupled with the first articulation band, wherein the eccentric cam is operable to drive the pivoting arm proximally in response to rotation of the first drive shaft, to thereby deflect the end effector away from the longitudinal axis. (i) a base , wherein the base is configured to couple with a dock of a robotic control system , (ii) a plurality of drive shafts oriented perpendicular to the longitudinal axis, wherein a first drive shaft of the plurality of drive shafts is rotatable to translate the first articulation band, (iii) an eccentric cam secured to the first drive shaft, and (iv) a pivoting arm coupled with the first articulation band, wherein the eccentric cam is operable to drive the pivoting arm proximally in response to rotation of the first drive shaft, to thereby deflect the end effector away from the longitudinal axis. <EOS>