# Experimental Design - Measuring Force Vector on Cable

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1. Jan 19, 2015

### Hexital

Hi All,

I'm trying to design an experiment for measuring force along a cable. The cable is will be held in a persons hand and the other end will be fixed to a transducer to measure the force of tension.

In order to account for the multiple force vectors, I thought of using a gimbal table or platform to ensure that the force sensor is able to reliably measure the majority of the force vectors and minimize any forces orthogonal to the plane of the sensor. These may be significant given the high degrees of freedom from a human hand tethered to the other end of the cable.

The sensor I'm thinking of using is this one: https://www.sparkfun.com/products/12873. The force applied should not exceed 50N.

Other than a gimbal table, are there any other methods available for reliably measuring the tension force along the cable using a unidirectional force sensor?

2. Jan 19, 2015

### SteamKing

Staff Emeritus
It's not clear which multiple force vectors you are concerned with. If you use the correct measuring instrument, there should be only one force vector being measured: the one in the cable.

Have you considered a simple dynamometer attached to one end of the cable, with the other end anchored? Something like so:

3. Jan 20, 2015

### Hexital

Thanks for your reply. The force sensor I mentioned is essentially a electronic dynamometer.

Re: the multiple force vectors I can provide some more detail regarding this experiment. I am trying to measure the force that surgeons apply while knot tying to ligate delicate structures. Two ends of a suture are held, one in each hand, during knot tying. A skillful surgeon will maintain constant tension on one suture while the knot is tied with the other. I thought of tying knots directly onto the force sensor, but some surgeons apply a significant amount of tension in a plan orthogonal to the plane of the force sensor e.g. horizontal rather than vertical when the sensor is oriented along the vertical axis. I am looking for a method for measuring the tension no matter what direction the tension is applied.

Thanks!