A surgical system for selective connection to a robotic arm (2, 3), the surgical system comprising: an instrument drive unit including: a first actuator (314a-d); a linkage member having opposing first and second portions (352b, 352a), the first portion operatively coupled to the first actuator (314a-d) such that actuation of the first actuator (314a-d) moves the first portion in a first direction and the second portion in a second direction opposite of the first direction; and a drive member operatively coupled to the second portion of the linkage member; and a surgical instrument detachably coupled to the instrument drive unit, the surgical instrument including: a driven member (262a-d) operatively associated with the drive member of the instrument drive unit; and an end effector operatively coupled with the driven member (262a-d), wherein translation of the driven member (262a-d) effects a first function of the end effector, wherein the linkage member is pivotally supported about a pivot disposed between the first and second portions (352b, 352a), and wherein the instrument drive unit includes a first elongate member having a first sleeve, said first sleeve configured to translate along the first elongate member, the first sleeve operatively associated with the first portion of the linkage member, such that rotation of the first elongate member pivots the linkage member about the pivot, wherein the first sleeve is threadably mounted on the first elongate member, and wherein the first sleeve has a first camming pin and the first portion of the linkage member defines a first slot configured to slidably receive the first camming pin of the first sleeve, whereby translation of the first sleeve causes relative movement of the first camming pin within the first slot. a first actuator (314a-d); a linkage member having opposing first and second portions (352b, 352a), the first portion operatively coupled to the first actuator (314a-d) such that actuation of the first actuator (314a-d) moves the first portion in a first direction and the second portion in a second direction opposite of the first direction; and a drive member operatively coupled to the second portion of the linkage member; and a surgical instrument detachably coupled to the instrument drive unit, the surgical instrument including: a driven member (262a-d) operatively associated with the drive member of the instrument drive unit; and an end effector operatively coupled with the driven member (262a-d), wherein translation of the driven member (262a-d) effects a first function of the end effector, wherein the linkage member is pivotally supported about a pivot disposed between the first and second portions (352b, 352a), and wherein the instrument drive unit includes a first elongate member having a first sleeve, said first sleeve configured to translate along the first elongate member, the first sleeve operatively associated with the first portion of the linkage member, such that rotation of the first elongate member pivots the linkage member about the pivot, wherein the first sleeve is threadably mounted on the first elongate member, and wherein the first sleeve has a first camming pin and the first portion of the linkage member defines a first slot configured to slidably receive the first camming pin of the first sleeve, whereby translation of the first sleeve causes relative movement of the first camming pin within the first slot. a driven member (262a-d) operatively associated with the drive member of the instrument drive unit; and an end effector operatively coupled with the driven member (262a-d), wherein translation of the driven member (262a-d) effects a first function of the end effector, wherein the linkage member is pivotally supported about a pivot disposed between the first and second portions (352b, 352a), and wherein the instrument drive unit includes a first elongate member having a first sleeve, said first sleeve configured to translate along the first elongate member, the first sleeve operatively associated with the first portion of the linkage member, such that rotation of the first elongate member pivots the linkage member about the pivot, wherein the first sleeve is threadably mounted on the first elongate member, and wherein the first sleeve has a first camming pin and the first portion of the linkage member defines a first slot configured to slidably receive the first camming pin of the first sleeve, whereby translation of the first sleeve causes relative movement of the first camming pin within the first slot.