An automatic solid material feeding system (ASMFS) consists of a conveyor, motor, controller, sensor, etc., and was used to consistently and continuously transfer solids from one position to another position under controlled conditions for various applications. The accuracy of an ASMFS depends on the size of the solid particle, mass flow rate of the particle, and design of the screw feeding system and control system. The ASFMS system was designed in CAD software and mathematically modeled using a bond graph. The bond graph approach is the most physical approach for understanding the true physics behind a system. The bond graph approach helped us to understand the system as a unified one despite having different subdomains within the system. The PID control of the mass flow rate was simulated using MATLAB. Various parameters, such as the mass flow rate of the particle and variables such as the motor speed and torque, are studied in this paper to achieve the desired steady-state value and time. Mass flow rate 1 kg/s with steady state time 1 sec. maintain with PID controller.

This paper addresses the passivity of continuous bioreactors around their non-zero equilibrium point by representing the system into a port-Hamiltonian system. In case of continuous bioreactors, the steady-state values of substrate(s) and biomass are not zero, thus passivity at shifted equilibrium point becomes interesting. A general representation of bioreactors is written in a form that allows to derive very simple conditions to prove their shifted passivity, using a quadratic energy function. In addition to that, the case of enforcing shifted passivity using feedback proportional control for general representation of bioreactors is also considered. Practical conditions are given for general single microbial reactions, and an example of anaerobic digestion of volatile fatty acids illustrates the multiple microbial reactions case.