Testing

To ensure that the finger design is suitable for the given application, we need to know the relationship between how hard the cable is pulled and the resulting forces at the finger tip. While modeling can give an estimate, it is important to validate these models empirically as well.

The transmission ratio can be determined by measuring the tension force in the pull cable using a force gauge, and measuring the resulting force at the distal segment of the finger as it pushes against a 3-axis load cell.

In the work by Gafford et al. (2014), the results of the empirical testing were compared to the results of the analytical model, and are shown in the graph on the right. The measured transmission ratio is about 23%, which is very close to the theoretical value of 25% as predicted by the analytical model.