The core principle of a force sensor is to convert applied force into a measurable electrical signal, primarily by detecting the physical changes in a material under stress.
The most common operating principle is based on the strain effect: when an external force is applied to an elastic body (such as a metal beam or diaphragm) inside the sensor, it undergoes minute deformation. The resistance strain gauge attached to the surface is stretched or compressed, causing a change in its resistance. This change is converted into a voltage signal by a Wheatstone bridge circuit, which, after amplification and processing, accurately reflects the magnitude of the force.
In addition, there are several other key principles:
Pierre resistance effect: Utilizing the property that the resistivity of semiconductor materials (such as silicon) changes directly under stress, this method offers higher sensitivity and is often used in miniature sensors.
Piezoelectric effect: Certain crystalline or ceramic materials (such as quartz and piezoelectric ceramics) generate surface charges under stress, making them suitable for dynamic force measurement but unable to detect static forces.
Capacitance change principle: By measuring the change in capacitance caused by the change in distance between two plates due to pressure, it has the advantages of low power consumption and high stability, and is suitable for static and dynamic pressure detection.
Modern force sensors often integrate signal conditioning circuits to achieve temperature compensation, noise filtering, and signal amplification, ensuring stable and reliable output. In fields such as robotics, industrial automation, and medical equipment, six-dimensional force sensors can also simultaneously measure force and torque in three directions, enabling precise force control operations.