Fabrication and characterization of 3D printed flexible capacitive pressure sensor for wearable devices and bio-mechanical applications

摘要

Biological monitoring technology based on pressure sensing is a very useful for human diagnosis method as an assistiveequipment, which should be comfortable on wearing position for user as well as and patient. Especially, pressuremonitoring for prosthetic arm and artificial leg is the critical element to maintain the safety of the amputees. In thisresearch, the fabrication and characterization of a novel flexible pressure sensor was done to measure the actual workingpressure between the surface of human body and assistive device for biomechanical techniques. The ultimate goal of thesensor design is targeted for use in robotic and prosthetic limb, where feedback and ability to detect forces associatedwith slip is crucial point. To fabricate the capacitive type pressure sensor, finite element method (FEM), additivemanufacturing (3D-printing) and signal processing were used. FEM simulation was performed with Comsol S/W foroptimal structure design to evaluate with the structural deformation and maximum capacitance value up to 500 kPa insensor range. Sensor with a full scale volume thickness under 10 mm were produced using FDM 3D-printingtechnique.A passive two-terminal electrical component part of capacitive pressure sensor was fabricated with conductivethermoplastic material and medium side of dielectric layer to keep soft and flexible structure. The output signal from thepressure sensor and related signal processing system was connected to a voltage divider circuit to amplifying the signal,multiplexer, microcontroller unit included analog to digital converter and indicating program. As a result, capacitivepressure sensing technology embedded in 3D printed structure can be considered for maintenance of stability andcomfortability to amputees.