Methods
The accuracy of the setup for measuring the force applied to the platform was validated by measuring standard weights which were put on the platform. A set of weights in the range from 1g to 100g were put on a precision scale with precision = 0.01g (Kern 572-35, Kern, Konolfingen, Switzerland) and the weight was noted. The weights were then put on the platform and the resulting force on the scale was recorded. The difference between those two measurements is due to the friction incorporated in the measurement system and accounts for any manufacturing tolerances of the weights. The weight displayed on the scale correlates with the force acting on the platform with:
\begin{equation} F_{\text{Scale}}={F_{0}-(\ F}_{w}-\mu_{0}*(F_{w}+F_{P}))\nonumber \\ \end{equation}
Where:
\begin{equation} {F_{0}=Force\ of\ the\ counterweight\ \backslash n}{Fw=Force\ exerted\ on\ the\ platform,\ \backslash n}{Fp=Force\ of\ the\ platfrom\ \backslash n}{\mu_{0}=friction\ coefficient\ of\ pulleys}\nonumber \\ \end{equation}
The friction determined with this validation data can further increase the accuracy of the catheter measurements, by adjusting the results by the known error.