Flexible Sensors For Tri-Co Robot Perception Based On Inkjet Printing Technology

Coexistence and collaboration between robots and people have become urgent needs in modern manufacturing and people’s daily life.Coexisting-Cooperative-Cognitive(Tri-Co)of human-robot-environment interaction(HREI)is the essential feature of the new generation of robotic systems.Because of human-robot interaction in unstructured and non-standardized dynamic environments,the intelligent sensing and autonomous control of Tri-Co robots,as well as the safety and comfort of human-robot interaction,have become frontiers in robotics.Intelligent sensing technology based on flexible electronics manufacturing technology is one of the key technologies for realizing intelligent interaction of Tri-Co robots,providing effective and reliable data sources for the intelligent sensing and autonomous control of Tri-Co robot.Concentrating on wearable exoskeleton robots and collaborative robots,which are typical examples of Tri-Co robot,this aims of thesis are list as follows: 1)to design and manufacture wearable and flexible sensors for single-model and multi-modal sensing;2)to explore the influence of multi-process manufacturing parameters on the sensing performance of wearable and flexible sensors with multi-scale and multi-function materials;and 3)to develop the visualization method of sensing information with multi-dimensional and multiparameters for integrated sensing systems.Main results are summarized as follows:(1)A piezoresistive sensing composite based on carbon nanomaterials is manufactured by leveraging the solvent-mixing method.A surface modification method based on laser ablation is proposed to effectively improve the resistance stability of sensing composite,addressing the issues in obtaining a stable electrical interface between sensing unit and flexible circuit when they are in a coplanar condition.In terms of inkjet printing technology,as one of flexible electronics manufacturing technologies,this thesis explores the relationship between the printable performance of conductive functional inks and the inkjet parameters of piezoelectric ceramic nozzles.A functional ink based on silver nanoparticles is finally adopted to fabricate flexible electrodes and flexible circuits.(2)To cope with the needs and challenges of flexible sensing technology for wearable exoskeleton robots in gait phase detection,this thesis attempts to enhance the ability of the robot to cognize the human motion intention.This thesis builds a wearable plantar pressure sensing system and a vision-based gait phase reference,on the basis of the inkjet-printed flexible circuit and proposed manufacturing method for the piezoresistive sensing composite.Based on the gait phase division method proposed by Perry,this thesis utilizing a machine learning method(k-Nearest Neighbor algorithm)to analyze the data sources from the two systems to divide the gait phase.According to the results,the quality of the resistance dataset obtained by the wearable plantar pressure sensing system is comparable to the quality of the joint angle dataset obtained by the vision-based gait phase reference system.The developed wearable plantar pressure sensing system has good sensing stability and user adaptability.(3)To cope with the needs and challenges of flexible sensing technology for collaborative robots in safe human-robot collaboration,this thesis aims to address the limitations of current collaborative robots in monotonous sensing function and simple safety control strategy.According to the suggestions of safety improvement methods from the ISO/TS 15066,this thesis design a robotic multi-modal sensing system to enhance the safety performance during human-robot collaborating,providing a two-level safe control strategy.The proximity sensing subsystem can control the operation speed of the robot according to the human-robot distance.The dome structure of the tactile sensing subsystem can realize distributed multi-point tactile sensing before the operator contacts the surface of the robot body.The dome structure improves the sensitivity of the sensor and the ability to cushion and absorb collision energy.