Feedback control of flow rate from a peristaltic pump using balance measurements

In many biotechnological processes it is important to perform exact dosing of the substrate into the bioreactor. The idea in this paper is to use the measurements from a balance to control the flow rate, since there is no access to the flow itself. The goals of the controller are several: it should be capable of handling load disturbances acting on the pump, measurement noise and even shocks acting on the balance. For this purpose an observer disregarding outliers is designed for low influence of the measurement noise. The observer-based feedback term compensates the load disturbances and the model errors. A dynamic feedforward structure is introduced to speed up the setpoint response. Simulations and experiments show that the suggested controller structure works well.