Periodicity and Power Minimization in Maglev Artificial Hearts

左心室辅助装置（LVAD）是成千上万患有终末期心脏病的患者的新兴治疗方法。这些“人造心脏”被植入体内，与天然心脏一起泵血。目前的（第二代）泵是旋转泵，其使用血液本身作为流体膜轴承中的润滑剂。该项目针对商业研究实验室正在开发的第三代泵，该泵采用反馈控制磁悬浮泵叶轮。磁悬浮消除了机械磨损和剪切引起的对血液（红细胞、血小板和白细胞）的损伤。受到磁悬浮的好处的激励，第一个磁悬浮泵于1998年在匹兹堡大学由该项目的成员植入动物试验中。该技术通过反馈控制、磁性材料的进步和受控设备的系统优化实现。然而，自然心脏的小尺寸、短时间常数、非线性、不稳定性和准周期性干扰对我们这些向患者承诺这种工程系统将维持他们生命的人构成了巨大的挑战。悬浮控制器设计中的基本权衡是功耗与鲁棒稳定性。此外，致动器、电力电子器件和控制设计的相互作用为显著的功率节省提供了机会。这项工作是针对效率增益与控制响应的改进，从自然心脏的准周期性压力扰动，和优化PWM波形驱动的电磁致动器。我们相信，从优化，非线性内部模型，非线性学习控制，并注意到有代表性的病人的血压波形的概念的扩展将导致一个强大的低功耗悬浮控制器的磁悬浮LVAD。一个成功的项目的结果将是安全的控制器用于医疗用途和便携式电池的重量显着减少。该项目的智力价值是跨学科的合作之间的权力和控制研究人员，心脏外科医生，和生物工程师;创新的扩展非线性控制理论的准周期干扰抑制;以及我们提出的用于开发驱动波形并将我们的想法传达给医学和工程界的实验装置。更广泛的影响将包括改善数千名心脏病患者的生活，培养连接控制理论和生物医学的博士生;发表被广泛引用的论文;开发一种仪器;在会议上展示我们的实验工作;以及继续PI的机器人计划，涉及来自代表性不足群体的180名K-12学生。

Left Ventricular Assist Devices (LVADs) are an emerging treatment for the thousands of patients suffering from end-stage heart disease. These "artificial hearts" are implanted and cooperate with the natural heart in pumping blood. The current (second generation) pumps are rotary pumps that use the blood itself as a lubricant in fluid film bearings. This project is directed at the 3rd generation of pumps being developed in commercial research laboratories which employ feedback-controlled magnetically-levitated pump impellers. Magnetic levitation eliminates mechanical wear and shear-induced damage to the blood (red blood cells, platelets, and leucocytes). Motivated by the benefits of magnetic levitation, the first magnetically-levitated pump was implanted in an animal trial by members of this project at the University of Pittsburgh in 1998. The technology was enabled by feedback control, advances in magnetic materials and systematic optimization of the controlled plant. However, the small size, short time constants, nonlinearity, instability, and quasi-periodic disturbances from the natural heart pose an awesome challenge to those of us who promise patients that this engineered system will sustain their lives. The essential trade-off in the levitation controller design is power consumption versus robust stability. Moreover, interactions of actuator, power electronics, and control design offer opportunities for significant power savings. This work is directed at efficiency gains associated with improvements of control response to quasi-periodic pressure disturbances from the natural heart, and optimization of PWM waveforms driving the electromagnetic actuators. We believe that the extension of concepts from optimization, nonlinear internal models, nonlinear learning control, and attention to representative patient blood pressure waveforms will lead to a robust low-power levitation controller for maglev LVADs. The consequences of a successful project will be safe controllers for medical use and a significant reduction in portable battery weight.The intellectual merits of this project are the interdisciplinary collaboration amongst power and control researchers, cardiac surgeons, and bioengineers; the innovative extension of nonlinear control theory to quasiperiodic disturbance rejection; and the experimental apparatus we propose for developing drive waveforms and communicating our ideas to the medical and engineering communities. The broader impacts will include improving the lives of thousands of heart disease patents, the training of PhD students bridging control theory and biomedicine; the publication of well cited papers; the development of a apparatus; exhibiting our experimental work at conferences; and the continuation of the PI's robotics program involving 180 K-12 students from underrepresented groups.