A robotic surgical system has a user interface with a control arm that includes a passive axis system for maintaining degrees-of-freedom of a gimbal rotatably supported on the control arm as the gimbal is manipulated during a surgical procedure. The control arm includes a swivel member, a first member, and a second member. The swivel member is rotatable about a first axis. The first member rotatably coupled to the swivel member about a second axis that is orthogonal to the first axis. The second member rotatably coupled to the first member about a third axis that is parallel to the second axis. The gimbal rotatably supported by the second member about a fourth axis that is orthogonal to the third axis. The passive axis system correlating rotation of the swivel member about the first axis with rotation of the gimbal about the fourth axis.