Dynamic characterisation of a three-dimensional micro-force sensor based on broadband optical coherence technology

Abstract Three-dimensional micro-force is critical in biomedical applications, such as tissue engineering, cellular mechanics, and minimally invasive diagnostics. However, despite their significant influence on measurement accuracy and reliability, the dynamic characteristics of three-dimensional force sensors remain underexplored. This study introduces a novel three-dimensional micro-force sensor leveraging broadband optical coherence technology and analyses its dynamic characteristics. The natural frequencies and vibration modes of the sensor were analysed using finite element simulations, and its dynamic response under varying conditions was studied using transient simulations. The transient response of the sensor under dynamic loading was validated using negative-step experiments. The first natural frequencies of the F x , F y , and F z components of the sensor were approximately 180 Hz, indicating excellent dynamic performance suitable for real-time applications. The intercomponent coupling effects were influenced by the structural design of the sensor and accuracy of the load application. The coupled output responses exhibited consistent oscillation periods and closely resembled the primary component responses in terms of dynamic behaviour, emphasising the importance of a precise sensor design. The dynamic performance of the sensor was significantly enhanced through pole-zero placement optimisation, which increased the dynamic response frequency in the F x and F y components from 110 to 245 Hz and in the F z component from 105 to 200 Hz. The findings of this study provide valuable insights into the design, optimisation, testing, reliability, and implementation of high-precision three-dimensional micro-force sensors in critical biomedical applications.