Development of bending gap measurement and position control technique for unmanned slab crane

The development of unmanned crane is an important issue of factory automation (FA) in steel industry. In slab yard, various kind of slabs(different ingredients, temperature, length, width and thickness and so on) are piled together. When hot slabs were piled and get cold gradually, deformation such as bending of slabs is occurred due to the thermal expansion and contraction. It may make slab to be bend and make gaps between slabs. Basically, gripping position control of unmanned slab crane is entirely depends on thickness information of target slabs in data base. The bending of piled slabs makes a difference of total task height between database and real one. It can cause unstable slab gripping and can cause a falling of slabs during the transportation. To resolve this problem, we developed a new gap measuring system which is equipped on the tip of crane and control system to make the crane grip stably. In this paper, a new gap measuring and grip position control system for slab crane and experimental results are described.