Accurate placement of furnace hood using EOT crane

Challenge Details

Steel coils weighing around 20T are covered with ‘Inner and outer Hoods’ in a Batch Annealing Furnace (BAF). First, the coils are stacked inside the furnace using tong crane and the inner and outer hood (Height around 5 meters and weight around 10 Tons) are placed next, one by one to cover the coils, using an Electric Overhead Traveling (EOT) crane. The Crane operator is required to position the hood very accurately (to a few mm accuracy) to match the guiding pole located near the furnace, which is very difficult as the operator cannot directly see the top of the guiding pole. The crane operator is guided by an operator standing on the ground, near the furnace, so that the hoods can be placed properly on top of the coils. It is a potential safety risk for the operator on ground as he is standing in directly under the overhead load. 

Several attempts were made in the past to solve the problem i.e., providing 2-way communication gadget (did not work because of the noise levels in the shopfloor), markings in specific locations (did not work as the accuracy required is in millimeters) and providing laser grids (did not work as it generated false alarms and halted the crane, creating further delay).

We are looking for a solution to guide the crane operator to position the furnace hood accurately and automatically, in the absence of the ground operator.