Mathematical modeling, design and optimization of conceptual configuration of soil-like substrate bioreactor based on system dynamics and digital simulation

It will be absolutely necessary to establish a Bioregenerative Life Support System (BLSS) for both manned exploration of deep space and subsequent founding of extraterrestrial colonies, a goal to which our species not only aspires but to which it likely must attain in order to insure its own future survival. Currently constraining the transport and transformation rates of substances in BLSS is the treatment of inedible plant biomass. To overcome this problem, a Soil-like Substrate (SLS) has been employed, rendering sustainable wheat cultivation from an otherwise inedible wheat biomass. The SLS bioreactor which is a specific artificial ecosystem consisting of wheat, earthworms, bacterial microflora, inedible wheat biomass and the artificial environment has theoretically been built in order to investigate the SLS formation process as well as the system's effective design and optimization. A valid mathematical model of the SLS bioreactor was developed and a performance index function (PIF) was put forward for sufficient description and comprehensive evaluation of the SLS bioreactor operation state, respectively. The closed-loop SLS bioreactor with a Linear-Quadratic Gaussian (LQG) servo controller was also designed through dynamic process optimization. The digital simulation on closed-loop SLS bioreactor indicated PIF could robustly stabilize at the desired level with desire dynamic performance specification under the action of artificial environment factors. Therefore, the closed-loop SLS bioreactor which might be built from the mathematical model and digital simulation has the potential to substantially increase both the closure degree and reliability of BLSS.