Additive manufacturing of inductive force sensor with NiZn-ferrite magnetic core for robotic gripper

Additive manufacturing (AM) is an innovative technology that overcomes the technical limitations of traditional ceramic manufacturing methods. AM offers unprecedented opportunities for the development of ceramic-based electronics with complex 3D structures, which can be imparted with electronic functionalities. In this study, inductive force sensors composed of a ceramic-based magnetic core and polymer-based helical spring were fabricated using various AM technologies. To ensure reasonable force-sensing performance, the response to the external force was controlled by controlling the spring constant of the helical spring and measured according to the change in inductance of the magnetic sensing circuit implemented in the sensor. The fully additive manu-factured (AMed) inductive force sensors exhibited outstanding sensing performance: they achieved a sensitivity of 0.139 mu H/N with good repeatability, high linearity (99.01%), negligible hysteresis (less than 0.01 mu H), and robust cyclic endurance. The sensor performance was further validated by building and testing a robotic gripper that employed an AMed inductive force sensor. This study offers an innovative way to manufacture a variety of sensors with complex shapes that can fit into dummy spaces allowed by the design of electronic devices, which will contribute to the effective integration of various electronic components in future electronic systems, such as robots.