I've now had a chance to run some coarse testing of the device. This was done by mounting a laser pointer directly to the moving platform, in the case of measuring the rotation angles. And then measuring the distance of deflection of the laser dot on a wall 3m away. In the case of measuring translation of the platform, the pointer was supported at one end so that, when the platform translated the pointer was rotated and the beam moved.

Measuring the translation showed a good match when moving 0.05mm for both UZ and UX (UY assumed to be equal to UX). For the rotations there was more variability but this is likely to be a function of the weight and inertia of the laser pointer with its x2 AAA batteries.

The test results PDF can be found in the files section. Overall I'm pleased with the capability, and i'm sure that the design can be taken further with a better choice of springs for the legs; slightly stiffer, with a varying diameter (wider in the mid-span) so that they are less likely to buckle in compression.

Figure; Laser pointer mounted to the platform (test rotations)