Evaluating the actual performance of a force sensor requires a systematic analysis from three core dimensions: accuracy, response characteristics, and stability, combined with a comprehensive judgment based on static and dynamic indicators.
Accuracy: Measuring the Reliability of Measurement Results
Accuracy reflects how close the sensor's output value is to the true value, and is the most critical indicator in selection. It includes several sub-parameters:
Linearity: The degree to which the sensor's input-output relationship deviates from an ideal straight line. High-quality products typically control this within 0.03%FS.
Repeatability and Reproducibility: The consistency of multiple measurements under the same conditions, reflecting the data's reproducibility.
Hysteresis Error: The phenomenon of inconsistent output for the same force value during loading and unloading; it should be minimized.
Resolution: The smallest force change that can be detected. High resolution is suitable for measuring minute forces (such as tactile feedback).
Temperature Drift: Zero-point or sensitivity shift caused by changes in ambient temperature. High-end sensors have built-in compensation circuits to reduce the impact.
Test Method: A high-precision standard force measuring machine is used to perform multi-point loading/unloading under a constant temperature environment, and the overall error (%FS) is calculated.
Response Characteristics: Ability to Capture Dynamic Changes For dynamic scenarios such as robotics and automated control, response speed is crucial:
Frequency Response Range: The range of signal frequencies the sensor can accurately respond to. Industrial-grade sensors typically range from tens of Hz to 2kHz, while high-end sensors can reach over 20kHz.
Step Response Time: The reaction speed to sudden force signals. Applications such as automotive safety testing require <5ms.
Natural Frequency: The vibration frequency of the sensor's own structure. A higher natural frequency indicates stronger resistance to external interference, suitable for high-frequency impact measurements.
Test Method: Input a step or sinusoidal sweep signal, record the output waveform through a high-speed acquisition system, and analyze rise time, overshoot, phase difference, etc.