An interface for a surgical system, comprising: an instrument drive unit including: a connection hub; and at least one drive shaft (260, 262, 264, 66) rotatably supported in the connection hub, the at least one drive shaft extending between and having a first end configured for connection with a motor and a second end having an oblique end surface (280, 580, 581); and a surgical instrument configured to be releasably connected to the instrument drive unit, the surgical instrument including: a connecting member; and at least one driven shaft (460, 462, 464, 466) rotatably supported in the connecting member, the at least one driven shaft extending between and having a first end and a second end, the second end having an oblique end surface corresponding to the oblique end surface (480, 680, 681) of the at least one drive shaft of the instrument drive unit, wherein the oblique end surfaces are configured to engage one another and are configured such that the connecting member of the surgical instrument is connectible with the connection hub of the instrument drive unit via a first connection pathway and a second connection pathway, the second connection pathway oriented transversely relative to the first connection pathway, characterized in that the oblique end surfaces are configured such that upon engagement of the second end of the at least one drive shaft of the instrument drive unit with the second end of the at least one driven shaft of the surgical instrument when the oblique end surfaces are not aligned, the at least one driven shaft of the surgical instrument rotates to orient the oblique end surface of the at least one driven shaft of the surgical instrument into flush engagement with the oblique end surface of the at least one drive shaft of the instrument drive unit in a single orientation of alignment. an instrument drive unit including: a connection hub; and at least one drive shaft (260, 262, 264, 66) rotatably supported in the connection hub, the at least one drive shaft extending between and having a first end configured for connection with a motor and a second end having an oblique end surface (280, 580, 581); and a connection hub; and at least one drive shaft (260, 262, 264, 66) rotatably supported in the connection hub, the at least one drive shaft extending between and having a first end configured for connection with a motor and a second end having an oblique end surface (280, 580, 581); and a surgical instrument configured to be releasably connected to the instrument drive unit, the surgical instrument including: a connecting member; and at least one driven shaft (460, 462, 464, 466) rotatably supported in the connecting member, the at least one driven shaft extending between and having a first end and a second end, the second end having an oblique end surface corresponding to the oblique end surface (480, 680, 681) of the at least one drive shaft of the instrument drive unit, wherein the oblique end surfaces are configured to engage one another and are configured such that the connecting member of the surgical instrument is connectible with the connection hub of the instrument drive unit via a first connection pathway and a second connection pathway, the second connection a connecting member; and at least one driven shaft (460, 462, 464, 466) rotatably supported in the connecting member, the at least one driven shaft extending between and having a first end and a second end, the second end having an oblique end surface corresponding to the oblique end surface (480, 680, 681) of the at least one drive shaft of the instrument drive unit, wherein the oblique end surfaces are configured to engage one another and are configured such that the connecting member of the surgical instrument is connectible with the connection hub of the instrument drive unit via a first connection pathway and a second connection pathway, the second connection pathway oriented transversely relative to the first connection pathway, characterized in that the oblique end surfaces are configured such that upon engagement of the second end of the at least one drive shaft of the instrument drive unit with the second end of the at least one driven shaft of the surgical instrument when the oblique end surfaces are not aligned, the at least one driven shaft of the surgical instrument rotates to orient the oblique end surface of the at least one driven shaft of the surgical instrument into flush engagement with the oblique end surface of the at least one drive shaft of the instrument drive unit in a single orientation of alignment.