A Flexible Piezoelectric-based Tactile Sensor for Dynamic Force Measurement

Force measurement is important in the robotic manipulation tasks, and it is an essential property of specific tactile sensor. An increasing number of studies demonstrated the capacity of tactile sensor in force measurement. However, most of the works focus on the static force measurement, the precise track of dynamic force is hard to be accomplished. Compared with traditional piezoresistive sensors, piezoelectric-based tactile sensors have advantages in low energy consumption and high sensitivity. This paper developed a flexible multi-layer piezoelectric-based tactile sensor inspired by the structure of skin. The size of sensor with a 3×3 sensing element array was designed to match that of a finger. The signal processors and logical algorithms were integrated to sense and distinguish the size, location and pattern of different external force stimuli in real time, including pressure intensity and vibration frequency. Two experiments about pressure sensing and vibration sensing show that the proposed tactile sensor with finger-like force range, high sensitivity and fast response time. The range of measured force amplitude and frequency were 0.1N-2N and 0.1Hz-100Hz. Another characteristic, the response time, was less than 50ms. In addition, the sensor array has a spatial resolution of 4 mm. This work has driven the development of tactile sensor for dynamic force measurement in real-Time robotic grasping.