Aircraft control cable tension measurement - uses stimulated vibration and resonant frequency measurement of clamped cable under tension

摘要

The tension measuring in cables transferring actuator movements to moving elements is relatively simple and a high accuracy. It is applicable mainly to aircraft flap and rudder controls cables etc. The cable (1) is clamped under tension at two points (2, 3:4, 5) at a defined distance from each other along the cable and oscillated between the clamps at its resonant frequency using an electromagnetic vibration stimulator. The tension P is then related to the resonant frequency, Wo, which is measured using a self-oscillation circuit (9, 11, 14, 7) in correspondence with the term P = Wo21V/K2TT, where 1 is the clamp separation, v the cable mass per unit length, and K a characteristic cable parameter. The arrangement is very reliable and gives reproducible results.