The problem of generating smooth parallel parking control for nonholonomic robot is addressed in this paper. A two-stage motion planner is designed considering collision avoidance, noholonomic constraints and control convergence. In the first stage, the robot is controlled to trace a double-tangential S-shaped (DTS) curve from
the starting point to an intermediate point. To ensure zero curvature, the DTS curve is composed of four segments: two arcs of circumference that forms a S-shape and two extension lines that connects to the initial and final configurations. A reference tracking controller is designed to enable the robot to move smoothly with
continuous steering profile along the DTS curve. While in the second stage, leveraging on the singularity property of the nonholonomic system, the robot can be asymptotically stabilized at the pre-determined pose with zero steering angle. The proposed parallel system incorporating two control stages is verified to outperform the existing approaches in terms of efficiency and robustness using a differential-drive model through simulation.