Investigating a novel 3D-printed electrical impedance tomography sensor for monitoring the interaction pressure on a customized physical interface in wearable robots

Abstract

Monitoring pressure distribution on the physical interface of wearable robots (including the cuff of the exoskeleton, rehabilitation robot, and the socket of the prosthesis) is crucial for ensuring safe and comfortable human-robot interactions. However, the complex contour of customized physical interfaces brings challenges in integrating sensors. To address this issue, we propose a novel method for sensorizing the interfaces based on a 3D-printed Electrical Impedance Tomography (EIT) pressure sensor, which is easy to customize, regardless of the complexity of the spatial working surfaces of the interface. Considering the anisotropic conductivity of 3D-printed parts, we first investigated its properties and examined its impact on EIT imaging using simple shape 2D planar sensors. Then, an adjusted Jacobian matrix was employed in imaging to reduce the impact of anisotropic conductivity on imaging. Finally, an EIT pressure sensor embedded physical interface was customized for the forearm using 3D printing and tested on a rehabilitation cobot. The online experimental results validated that it can effectively monitor the distribution and variation of pressure between the human body and the interface.