To improve safety and productivity, it is often important to know the position of the crane hook with high accuracy. Moreover, the position of the hook and the load on it must be known not only in XYZ coordinates relative to the walls, but even more importantly, relative to other mobile objects. Also, it is often important to know both the XYZ coordinates and the hook swing and twist angle.
So how do you track the position of a hook of overhead cranes with high accuracy in a typical industrial environment where RTK GPS is not available because GPS is not available at all? Recommended solution – Marvelmind Precise Indoor “GPS”.
Key features of the system:
High-precision tracking of a crane hook does not fundamentally differ from tracking any other object in 3D, but has its own practical implementation features.
As with any high-precision tracking system, the system should include:
Then, of course, it is important to clearly understand what is positioned/tracked/localized against what:
There are two major options:
Each of the approaches has pros and cons. Which one to choose mostly depends on the requirements and limitations of the particular project you have.
See more insights about different options for tracking of the crane hook in the video below.
Remember the most important requirement for precise tracking system: to have tracking the mobile beacon must have a direct line of sight (hearing) to two or more stationary beacons within 30 meters for 2D or three or more for 3D.
Tracking of a crane hook requires 3D tracking, obviously.
3D tracking (XYZ) is just a subset of multilateration. It is not fundamentally more complex than 2D (XY) tracking. Simply, at any given time the mobile beacon on the hook must have a direct line of sight to 3 or more stationary beacons within 30m for 3D instead of 2 or more stationary beacons for 2D.
3D positioning is not drastically different from 2D positioning. But it does have implications. For example:
Since the line of sight between stationary beacons and the mobile beacons is the most important requirement, the size of the hook becomes an issue.
The hook is typically so huge, that it creates shadows and it is impossible to track it in 3D (XYZ) easily. One has to install too many stationary beacons to track a mobile beacon on the hook.
Instead, it is recommended to combine with installation of additional mobile beacons on the hook. It saves the costs of the system, increases the resilience against obstructions – both near the stationary beacons and near the mobile beacons – and improves overall performance, because distances between the stationary beacons are known. If more than one mobile beacons are visible to the stationary beacons, it is possible to calculate the position of the hook with higher accuracy based on the location of more than one mobile beacon
Yes, forklifts and AGVs can be dangerous, but huge overhead loads are even more dangerous, particularly, when dealing radioactive materials or high-cost bulky products.
Therefore, particular focus on resiliency and accuracy of the system is important.
An example overhead crane system:
Such monstrous system requires larger indoor positioning system. It may have significantly fewer beacons, but the distances between them may be significantly larger. In its turn, it would require special solutions to increase the range, for example, Marvelmind Horn to increase ultrasound range and directional antennas to increase radio range