BioSys: Efficient Quality Control System for Manufacturing of Sustainable Biopolymer Composites

Biopolymer-bound soil composites (BSC) are a novel class of cement-free building materials utilizing starch, protein, and lignin binders. While BSC are sustainable composite materials suitable for a wide range of construction applications, their manufacture is complicated, as quality issues (internal defects, improper mixing, improper compaction, etc.) may occur during manufacture. Even though conventional vision-based or acoustic-based quality control methods might be able to detect quality issues during the manufacture of BSC, they are unable to easily monitor the unique strength gain process of BSC that occurs when the wet material dries out. Conventional quality control methods are usually tailored to a single quality issue such as crack formation, requiring the use of multiple methods to completely verify material quality, which is inefficient. To address these issues we propose BioSys, a multi-functional quality control system to enable large-scale manufacture of BSC through non-destructive vibration-based testing. BioSys is multi-functional in the sense that it is used to: (1) identify internal defects (crack formation and improper mixing); (2) detect improper compaction; and (3) monitor desiccation. Unlike current methods, BioSys performs these tests in an efficient, non-intrusive manner, by generating signals from an impulse hammer tapping at different locations on a BSC specimen and measurement of response signals from an accelerometer. BioSys contains two different machine learning pipelines trained on the resulting time-series data with accuracy of up to 99% for defect detection and up to 100% for detecting improper compaction. BioSys reaches a MAPE of 5% for monitoring the strength gain of BSC during desiccation.