Force Transducers for Military Applications
Force sensors and transducers convert a mechanical load input, such as tension, compression or weight, into an electrical voltage that can be measured. Since the electrical signal changes in proportion with the applied force, it can easily be used to find a value for the size of the force.
Load cells make up the largest category of force transducers and sensors. They use a wide variety of technologies to measure the input force and create the output signal, including:
Inductive load cells – use an inductor, consisting of a coil of wire with a ferromagnetic core. The applied force changes the position of the core within the coil, thus affecting the inductance.
Capacitive load cells – the applied force changes the distance between the two plates of a capacitor, and hence the capacitance.
Piezoelectric crystal load cells – applying a load to the crystal deforms it, which in turn affects its electrical charge.
Magnetostrictive load cells – applied force to a ferromagnetic material changes the magnetic properties of the material.
Pneumatic load cells – use a flexible diaphragm and a chamber of pressurized gas. The pressure resulting from force applied to the gas is measured and converted to an electrical signal.
Hydraulic load cells – similar to pneumatic load cells, but use pressurized liquid such as oil or water.
Strain gauge load cells – use an element that changes electrical resistance as an applied force deforms it.
Force sensors and transducers are used in a wide range of military and defense applications, particularly in testing. They can be used to measure the load on aircraft engines, parachutes, weapons and hardware attachments, wings and flight surfaces, and more. They may also be used to measure the effect of impact from projectiles or explosions on infantry and vehicle armor.
Force measurement sensors can also be used as part of a haptic feedback system in remote and robotic systems, such as those that allow operators to perform bomb disposal via a robotic arm.