A global sliding mode controller design for an intra-aorta pump.
Both the intra-aorta pump system and the circulation system are nonlinear systems with external perturbation and internal uncertainty. Classical control methods are suggested for linear systems. Therefore, a global sliding mode controller (GSMC) is reported in this article. A dynamic disturbance compensator was used to estimate the uncertainty of the controlled intra-aorta pump system for eliminating chattering effect. Simulations were performed to verify the robustness and dynamic characters of the controller. Simulation results demonstrate that the chattering effect of the controller output is eliminated. The settling time of step response of flow rate (5 L/min) is 0.08 seconds without overshot or steady-state error. When the load torque step disturbance increases to 0.4 Nm, the settling time of the controlled system is 0.025 seconds. When the desired flow rate is pulsatile flow, the dynamic response time is 0.08 seconds, and the maximum flow rate error is 0.03 L/min. To verify the dynamic character of the GSMC, an experiment was conducted. Because the feedback frequencies of rotational speed and flow rate in the experiment were slower than the ones in the simulation, the performance of the controller deteriorates. The experiment results illustrate that the settling time of step response of flow rate (5 L/min) is 0.26 seconds, and the flow rate error is 0.1 L/min.
Department of Biomechanics, School of Life Science and BioEngineering, Beijing University of Technology, Beijing, People's Republic of China. changyu@bjut.edu.cn
Yu
Y
Chang
Bin
B
Gao
D001698:Biomedical Engineering; D003198:Computer Simulation; D003326:Coronary Circulation; D006353:Heart-Assist Devices; D018056:Hemorheology; D006801:Humans; D066298:In Vitro Techniques; D007423:Intra-Aortic Balloon Pumping / Q000295:instrumentation*; D008955:Models, Cardiovascular; D017711:Nonlinear Dynamics; D011474:Prosthesis Design