* Question
The essence of dynamic calibration is to determine the dynamic parameters of the sensor experimentally.What are the two methods of this type?
* Answer
The two main methods of dynamic calibration for sensors are:
1. Comparison Method
This method involves comparing the sensor under calibration with a reference sensor that has already been calibrated dynamically. Key aspects include:
Both sensors are subjected to the same dynamic input (e.g., shock, vibration, pressure wave).
The output of the test sensor is compared to the reference sensor’s output to determine dynamic characteristics such as:
Frequency response
Phase shift
Amplitude linearity
Example: Using a calibrated accelerometer mounted next to the sensor under test on a vibration exciter.
2. Analytical or Direct Method
This method determines dynamic parameters by applying a known dynamic input to the sensor and analyzing the sensor’s output response. It typically involves:
Using a controlled stimulus (e.g., impulse, step, sine wave).
Applying mathematical modeling or system identification techniques to derive:
Transfer function
Damping ratio
Natural frequency
Sensitivity to dynamic inputs
Example: Applying an impulse load to a pressure sensor and analyzing the time-domain or frequency-domain response.
Summary
Method | Description | Key Requirement |
Comparison | Compare output with a known reference sensor under same conditions | Calibrated reference sensor |
Analytical | Apply known input and analyze sensor output using system identification | Accurate input control and data modeling |
Both methods aim to evaluate the dynamic behavior of sensors such as response time, frequency bandwidth, and transient performance, which are critical in high-speed or time-varying measurement environments.
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