A force sensor is an electronic component that converts force into a measurable electrical signal. It is widely used in industrial automation, robotics, and automotive manufacturing.
Its basic characteristics are as follows:
Core Functions: It can detect mechanical quantities such as tension, strain, pressure, weight, torque, internal stress, and strain, and is a key component for force control and weighing.
Composition and Structure: It mainly consists of three parts:
Force-sensitive element (elastic body): Made of materials such as aluminum alloy, alloy steel, and stainless steel, it deforms under force.
Conversion element: The most common is a resistance strain gauge, attached to the elastic body, which changes its resistance value with deformation.
Circuit section: Includes a Wheatstone bridge, PCB board, enameled wire, etc., used for signal conditioning and output.
Working Principle: Depending on the type of sensor, it is mainly based on the following physical effects:
Strain gauge type: Utilizes the resistance strain effect of metal or semiconductor materials. External force causes the strain gauge to deform, and the change in resistance is converted into a voltage signal through a bridge circuit.
Piezoelectric: Based on the piezoelectric effect, a quartz crystal generates an electric charge when subjected to force, which is then converted into a voltage signal by a charge amplifier. Suitable for dynamic measurements.
Capacitive: Measures force by measuring the change in capacitance caused by the change in the distance between two conductor plates.
Optical: Utilizes the influence of fiber bending or refractive index changes on light transmission characteristics to achieve non-contact, high-precision measurement.
Classification Methods:
By Measurement Principle: Strain gauge, piezoelectric, capacitive, piezoresistive, optical, etc.
By Measurement Dimension: One-dimensional (unidirectional force), three-dimensional (tridirectional force), six-dimensional (tridirectional force + tridirectional torque), the latter often used for high-precision force control in robots.
Key Performance Indicators:
Accuracy and Repeatability: High-end sensors can achieve an accuracy of 0.01% and a repeatability of 0.5% F.S.
Measuring Range: From a few grams to hundreds of tons, such as the Ningbo Keli IL series covering 50 kg to 2 tons.
Temperature stability: Temperature drift compensation (TKzero) and sensitivity temperature compensation (TCS) are required to improve stability.
Output method: Analog signal (e.g., mV/V) or digital signal, supporting multiple interface protocols.