Calculating the force introduction point with PMX

The coordinates of a force F to be measured can easily be determined with three force transducers F1, F2 and F3.

Force F is the sum of the three individual forces:

The counters for the x and y calculation are determined in an interim step. Coordinates x1, y1, x2,....are in the factors of the summands.

For x:

For y:

Finally x and y are calculated with two divisions. The calculation for x is shown here (y is similar):

Implausible values in unloaded state

Noise predominates when F is close to zero. Implausible values are returned for x and y:

Remedy: Output for x and y is not regular until F is greater than 1 N, for example. Otherwise zero will be returned each time.

A trigger block sets Flag_01 if F is greater than the minimum value:

The two limit values for the trigger. Only the lower switching threshold is required for 1 N. A value is selected for the upper threshold that is far above the measuring range:

Two multiplexer blocks switch between zero and the calculated values. Shown here for x:

1. In case of division by zero, a divisor block returns Not-a-Number (NaN).
2. Polar coordinates can also be returned if necessary:

The settings for radius....:

Representation of a moving force with catman in polar and Cartesian coordinates: