Indoor positioning system for precise hook tracking in a hot-rolled steel coil plant

Summary

Indoor positioning system for hook tracking on a coil yard of a hot-rolled steel coil plant.

  • Task
  • Total Area
  • Quantity
  • Autonomous
  • Indoor only
  • Operations
  • Temperatures
  • Hook tracking
  • Up to 400 x 36m
  • 1-4 hooks/cranes
  • No. Tracking only
  • Yes
  • 24x7x365
  • Up to 100°C

Task

To identify the hook position (and hence the coil position) in the 3D space within a hot rolling plant’s yard of one of our customers.

The coils are quite hot when rolled, posing safety and reconciliation challenges when moving them around.

Coils are stacked up to two rows, one on top of the other, during an inventory surge. To retrieve the coil from the bottom layer, they often have to move the coil(s) placed on the top row, so that they can access them from the bottom.

While this reallocation happens, the coil tracking becomes an issue, requiring a person to enter the location manually.

Conditions

  • Very large (hundreds of meters) open space. No or little obstructions
  • Indoors only, but very high temperatures of up to 100°C near the coils

We can’t publish the customer’s yard photo. Thus, the pictures below are pooled from the internet. They resemble the customer’s yard very closely

Hot-rolled steel coils
Hot-rolled coils steel plant

Solution

There are two distinct solution options possible for this case:

  1. To localize the hook against the stationary beacons placed on the columns or walls. The hook’s position – either 3D or 2D – is calculated as the position of a mobile beacon placed on it (for 3D) or on a crane’s cabin (for 2d)
  2. To localize XYZ as 1D in X (reels along the production hall), 1D in Y (across the hall), and 1D in Z (height of the hook against the crane)

Option 1 requires more beacons than Option 2 and is more prone to potential non-line-of-sight situations. It is most suitable when not only hooks are tracked, but also other objects, such as people, vehicles, AGVs, and robots. In this case, the same stationary beacons are used for the localization of all mobile beacons, including those on hooks, people, vehicles, and robots.

The most significant benefit of Option 2 is simplicity and lower costs of the solution:

  • Since 2D/3D tracking is done as a combination of 1D (for X) + 1D (for Y) + 1D (for Z), it is possible to use Horns. They provide both a larger range – up to 100 meters instead of the recommended 30 meters for 2D and 3D with Industrial Super-Beacons – and better protection against the industrial acoustic noise
  • Thus, for example, when the customers want to play very safely instead of the maximum possible range of 100 meters, they choose to place beacons along the X axis every 50 meters and put the required 5-10-meter handover zone, they need only 8 x Industrial-RX with Horn for the 400-meter hall. Whereas with regular Industrial-RXs, they would need 400/25 = 16 beacons, i.e., twice as many. The Horns provide a much better acoustic noise immunity at the same time

Recommended configuration

As in previous crane tracking cases, we recommended a solution when XYZ tracking is built as 1D tracking in X + 1D tracking in Y (crate’s position on the crane) + 1D in Z (hook height) since the customer hasn’t expressed strong interest in a more broad usage of the system (expanding to people, vehicle, and robot tracking) focusing on the primary task – tracking hooks/coils.

Options, upgrades, and expansions

Scroll to Top