Design, simulation and analysis of a positive displacement pump controller for biomedical applications requiring pulsatile flow

The increased interest in applications of positive displacement pumps in biomedical instrumentation and research demands a challenge in the manufacturing of systems with particular accuracy and reliability. A proof-of-concept control system to drive the electrical actuator of a positive displacement pump is presented. The design of this controller incorporates the Dirac comb function as a generator of the clock/step to command the driver. The implementation is a microcontroller-based stepper motor approach, which consists of a microcontroller, driver, bipolar stepper motor and a basic model of positive displacement pump. The control model is designed and tested for different types of movements as a function of a theoretical torque generated in the pump shaft. The capabilities of this system to produce controllable pulsatile flow movement of the stepper motor operating at different frequencies are demonstrated. At low frequencies, the level of vibration is raised, on the contrary, frequencies greater than 400 Hz produce smooth rotation of the pumping system. Finally, the influence of the pulsatile flow generated for this kind of pump is evaluated in a biomedical example.