<div>In dynamic environment, the suddenly appeared
</div><div>human or other moving obstacles can affect the safety of the
</div><div>bridge crane. For such dangerous situation, the bridge crane
</div><div>must predict potential collisions between the payload and the
</div><div>obstacle, keep safe distance while the swing of the payload must
</div><div>be considered in the mean time. Therefore, the safe distance is
</div><div>not a constant value, which must be adaptive to the relative
</div><div>speed of the bridge crane. However, as far as we know, the
</div><div>mathematical model between the safe distance and the relative
</div><div>speed of the bridge crane has never been fully discussed. In
</div><div>this paper, we propose a safe distance prediction method using
</div><div>model prediction control (MPC), which can make sure that the
</div><div>crane can stop before the obstacle, and avoid possible collisions,
</div><div>while the relative speed and anti-swing are both considered. The
</div><div>experimental results prove the effectiveness of our idea.</div>