The Different Types of Errors in Force Measurement

Force Measurement Curve with an Offset

The measured force curve (labeled “Offset” in the image) is shifted relative to the actual force curve. This is usually due to an omission or an incorrect zero calibration of the measuring device.

Graph of a Measurement with Excessive Gain

The error varies linearly with respect to the true value. In this example, the greater the measured force, the greater the error. The measured value deviates from the true value.

Generally, this error is caused by an incorrect gain setting on the data acquisition system or a poor-quality sensor.

The linearity error:

Graph of a Measurement with Linearity Error

In this type of case, the measured value does not form a straight line. The deviation between the true value and the measured value varies depending on the value. This error is often caused by a poor-quality sensor. However, there is always a slight linearity error, regardless of the sensor..

Error Due to Hysteresis

Hysteresis occurs when the measurement result depends on the previous measurement. This generally results in different results when performing multiple measurements on samples.

Curve of a Measurement with Quantization Error

The measured curve—and thus the error—appears stepped. Most often, this error is due to a digital error: too low a sampling rate, an analog-to-digital conversion problem, etc.

Generally speaking, the higher the sampling rate, the smaller this error becomes. Typically, a sensor sampling rate of 100 Hz is the minimum required.