Inspired by swimming micro organisms, swimming micro/nano robots (SM/NR) hold great potential in medical applications and microfluidics research. Applications are many: targeted drug delivery, minimally invasive surgery, gene therapy, diagnosis, and as manipulative agents in microsystems such as lab-on-a-chip devices. Our research aims to develop controllable navigation of SM/NR with helical tails in confinements. We design and manufacture millimeter-scale robots with the 3D printing technology. The swimmers are propelled by rotating magnetic fields inside channels filled with viscous fluids to ensure physical similarity with the micro swimming conditions from fluid mechanics point of view. Experiments are conducted to obtain the positions, trajectories, velocities and orientations of the swimmer. In addition to experimental studies, Computational Fluid Dynamics (CFD) models are developed to study the flow field around the swimmer, and for simulation experiments.