Measurement of Tension in a String Using an Array of Capacitive Force Sensors

The measurement of tension in strings and soft tissues is of critical importance in many applications, including orthopedic surgeries. Various sensors have previously been designed for the measurement of tension, but they all require either attachment of the sensor to the string or the use of an external-inertial reference. This paper presents two new sensors to estimate tension in strings without the need for attaching any devices on the string or a need for an inertial reference. Both sensors employ an array of three capacitive force measurement devices and estimate the tension based on these three readings. Experimental data show that the sensors can measure tension values up to 100 N on a bench-top test rig.