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Investigation of parameter estimator and adaptive controller for assist pump by computer simulation
T Shimooka1, Y Mitamura, T Yuhta
1Department of Biomedical and Material Engineering, School of Engineering, University of Hokkaido, Japan.
Artificial Organs
|April 1, 1991
Summary
This study simulated a multi-output adaptive controller for left ventricular assist devices (LVADs). The controller effectively regulated aortic and atrial pressures, demonstrating potential for more complex circulatory control.
Area of Science:
- Biomedical Engineering
- Control Systems Engineering
- Cardiovascular Physiology
Background:
- Left Ventricular Assist Devices (LVADs) are crucial for managing heart failure.
- Effective control of hemodynamic parameters like mean aortic pressure (mAoP) and mean atrial pressure (mLAP) is vital for LVAD performance.
- Existing control systems may face challenges in adapting to dynamic changes in the circulatory system.
Purpose of the Study:
- To investigate the efficacy of a multi-output adaptive controller for an LVAD.
- To assess the controller's ability to regulate both mAoP and mLAP under simulated physiological changes.
- To evaluate the controller's adaptability and potential for managing multiple circulatory outputs.
Main Methods:
- Computer simulations were employed to model the circulatory system using autoregressive models.
- Recursive least squares method was utilized for parameter estimation of the circulatory models.
- A performance index, a weighted summation of square errors, guided the search for optimal vacuum pressure (controller input).
- Simulations included scenarios with decreased left ventricular contractility and altered peripheral resistance.
Main Results:
- The adaptive controller successfully regulated both mAoP and mLAP to their target values in steady-state conditions.
- Achieved steady-state errors were minimal: <3 mm Hg for mAoP and <1 mm Hg for mLAP.
- Estimated model parameters were found to accurately represent the true circulatory parameters.
- The controller demonstrated robust performance despite dynamic changes in cardiovascular conditions.
Conclusions:
- The simulated multi-output adaptive controller shows significant potential for precise LVAD control.
- The controller's ability to manage multiple outputs suggests adaptability to varying circulatory conditions.
- This adaptive control strategy offers a promising approach for enhancing LVAD therapy and patient outcomes.