A robotic system assembly comprises a robotic manipulator including an actuator assembly and a surgical instrument having a base body mountable to the actuator assembly. The base includes a first control input and a second control input, wherein the first and second control inputs are positioned on different sides of the base. The actuator assembly is moveable between open and closed positions to facilitate removal and replacement of surgical instruments. When in the closed positions, drive elements of the actuator assembly are positioned to drive the first and second control inputs of the surgical instrument to cause end effector movement or actuation.