Real time implementation of PID and active force control for feedrate control of a syringe fluid dispenser

Abstract

A method to control the flowrate of a syringe fluid dispenser using Active Force Control strategy (AFC) was carried out based on a simulation and experimental investigation. The AFC technique has been shown to compensate known and unknown disturbances in the system through the appropriate estimation of the inertia matrix of the physical system. The simplicity and effectiveness of the method in compensating the disturbances is demonstrated without relying on heavy mathematical computation. The objective of this study is to implement the AFC strategy to control the flowrate of the fluid in syringe feeding system. The performance of the AFC scheme was compared with the conventional proportional-integral-derivative (PID) controller to determine the robustness of the controllers in the dynamical systems. For sensitivity analysis purpose, AFC strategy was studied based on its performance with the value of the estimated inertia and the percentage of AFC applied to the system varied within a selected range. Simulation study was done to theoretically verify the model of the syringe fluid dispenser system. An experimental prototype of the syringe fluid dispenser system was then designed and developed to validate and complement the theoretical study. The development of the experimental rig was done by integrating the mechanical, electrical/electronic and computer software control. The results determined from both the simulation and experimentation works were analysed and compared to study the performance in terms of the proposed system robustness and accuracy against various operating and loading conditions. It is obvious that the AFC scheme performance is much superior in terms of both the robustness and accuracy even in the presence of introduced disturbances in comparison to the PID control scheme.