In dynamic environment, the suddenly appeared

human or other moving obstacles can affect the safety of the

bridge crane. For such dangerous situation, the bridge crane

must predict potential collisions between the payload and the

obstacle, keep safe distance while the swing of the payload must

be considered in the mean time. Therefore, the safe distance is

not a constant value, which must be adaptive to the relative

speed of the bridge crane. However, as far as we know, the

mathematical model between the safe distance and the relative

speed of the bridge crane has never been fully discussed. In

this paper, we propose a safe distance prediction method using

model prediction control (MPC), which can make sure that the

crane can stop before the obstacle, and avoid possible collisions,

while the relative speed and anti-swing are both considered. The

experimental results prove the effectiveness of our idea.