Haptic sensors based on piezoelectric sensor arrays with pin-type modules which have high responses and dynamic sensing capabilities were designed and studied for surface topography measurements. Unlike the human finger, most flexible tactile sensor designs do not detect well the depth information of surfaces which change at the ~mm level despite the fact that they have a good sensitivity for pressure or force. To enhance the ability to detect depth information of the surfaces of objects, a piezoelectric sensor combining a pin-type module with excellent monitoring in the depth direction by spring is developed here. Because spike types of piezoelectric signals do not match directly a specific surface topography, a signal processing method that reconstructs the surface topography was studied considering the piezoelectric working principle and spring dynamics. According to the sensor design, it can detect 3mm depth changes with a two-dimensional plane structure at mm-level resolutions. The results showed that that the proposed sensor could measure various shapes and depth profiles precisely via a sliding motion, and the surface topography was reconstructed through highly accurate measurement results, similar to a human.
