• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.326-329
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• 2004

In this paper, we show a new form of blood pressure controller combined PI control with $H_{\infty}$ loop-shaping. Hypertensive patients or post-operative patients need to maintain normally blood pressure. Exact regulation of blood pressure is needed for maintaining variable blood pressure of preventing complications. The regulation of blood pressure is achieved by injecting drugs, and usually sodium nitroprusside is used as those kinds of drugs. It is necessary to control the infusion rate sodium-nitroprusside carefully to achieve the desired blood pressure. It has been known that regulation of blood pressure by automatic controller is more effective than regulation of blood pressure by human operators. The control of blood pressure has many constraints and uncertainties. Most of biological system has the time-varying variables and the side effects such as increased risk of sepsis and organ failure. To solve such a problem, we design a new robust PI controller using $H_{\infty}$ loop-shaping to decrease noise effects that come out from human body and errors for time delay. The system with designed controller shows more stable control of mean blood pressure and more robust performance for uncertainties. Validation methods for the control performance are confirmed to computer simulations.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.1
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• pp.49-55
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• 2019

This study proposes a robust control of a fin position servo system using the H-infinity loop-shaping method. The fin position control system has a proportional (P) position controller and a proportional-integral (PI) controller. In this work, the position control loop requires a wide bandwidth. No current control loop exists due to the compact design of the system. Hence, the controller parameters are difficult to determine using the traditional cascade design method. The $H_{\infty}$ controller design method is used to design the controller's gain to achieve good performance and robustness. First, the transfer function of the system, which can be divided into tunable and fixed parts, is derived. The tunable part includes the position P controller and speed PI controller. The fixed part includes the rest of the system. Second, the optimized controller parameters are calculated using Matlab $H_{\infty}$ controller design program. Finally, the system with optimized controller is tested by simulation and experiment. The control performance is satisfactory, and the $H_{\infty}$ controller design method is proven to be valid.