To be able to monitor forces acting on objects is important for a lot of different applications. In this case the object is a big steel disc and the forces to be monitored are those acting on the rim of the disc.
This is done with strain gauges that register changes in the internal strainfield. This is then run through a system model that outputs the equivalent force for that strainfield. The system model is created through a static system identification consisting of a series of test pushes on the rim of the disc. This method of system identification has a series of problem mainly that it is time consuming.