A system comprises an instrument carriage configured to support an instrument. The instrument comprises a joint output and an input coupling configured to move the joint output. The instrument carriage comprises an actuating element. The actuating element comprises a drive input and an actuator coupled to drive the drive input. The drive input is configured to engage the input coupling. The system also comprises a control system configured to drive the drive input with the actuator and determine whether the drive input has engaged the input coupling based on a determination of whether the actuator experiences a resistance greater than a resistance threshold.
