A Fingertip Sensor for Wire Retention Force Test of Electrical Connector Using Pressure Control on Textured Elastic Friction Pair

Wire retention force is an important indicator for evaluating the reliability of wire insertion in electrical connectors. Current approaches to measure this force are mainly relied on spring-based dynamometers, which are limited by their large sizes and lack of digital testing capabilities. Herein, this article proposes a retention force sensor by controlling the critical friction force between the wires and textured rubber friction pair installed on fingertip. A conversion model between the normal pressure applied to the friction pair and the wire retention force was established, by combining experimental calibration and machine learning methods. Results show that the relative testing error of retention force using this fingertip sensor is less than 8%, and the coefficient of determination ${R}^{{2}}$ of the sensor is better than 0.908 within the retention force range of 2–16 N. After 1000 cycles of retention force testing, the testing error of sensor can still be maintained within 10%, indicating that the sensor has good long-term performance stability.