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Accuracy of the HeartMate 3 Left Ventricular Assist Device Flow Estimation

Scientific reports 2025年第1期15卷 18971页

作者： Theodor Abart Marko Grujic Philipp Aigner Michael Röhrich Stefan Jakubek Daniel Zimpfer Marcus Granegger Christian Doppler Laboratory for Mechanical Circulatory Support Department of Cardiac and Thoracic Aortic Surgery Medical University of Vienna Vienna Austria. Department of Anesthesia Intensive Care Medicine and Pain Medicine Medical University of Vienna Vienna Austria. Division of Control and Process Automation Institute of Mechanics and Mechatronics Vienna University of Technology Vienna Austria. Christian Doppler Laboratory for Mechanical Circulatory Support Department of Cardiac and Thoracic Aortic Surgery Medical University of Vienna Vienna Austria. marcus.granegger@meduniwien.ac.at.

Left ventricular assist devices (LVADs), such as the HeartMate 3 (HM3), are a treatment option for advanced heart failure (HF). Non-invasive monitoring of heart-pump interaction is crucial but relies on estimated parameters only. Despite the widespread clinical utilization of HM3 estimated flow rate (Q) and pulsatility index (PI) their accuracy was not yet quantified. This study assessed the HM3 monitoring by describing underlying physical characteristics, estimation algorithms and deriving accuracy of estimates in clinical practice. Identification measurements were performed to quantify the physical characteristics and mechanisms of flow estimation. Virtual patients coupled to a hybrid hock circulatory loop were employed to evaluate estimator accuracies in realistic operating conditions. The correlation between Q and torque-generating-current was strong (r² > 0.99, p < 0.001), confirming that estimation is based on speed, current, and viscosity. Also, the PI is directly derived from current. However, the underlying current/flow relationship is ambiguous (one current value corresponds to two flow rates). The HM3 flow estimator showed an RMSE of 1.63 L/min and a correlation coefficient of r = 0.86 (p < 0.001). The non-linear relationship obscures the systolic portion of flow as current declines during peak systole at higher flow rates. HM3 monitoring is unable to accurately represent the actual hemodynamics, particularly in the transition between full support and partial support, which is a region highly prevalent and crucial in clinical practice. It is therefore recommended to interpret values and trends of the HM3 monitoring system with caution.

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Regret and cumulative constraint violation analysis for online convex optimization with long term constraints

arXiv

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arXiv 2021年

作者： Yi, Xinlei Li, Xiuxian Yang, Tao Xie, Lihua Chai, Tianyou Johansson, Karl H. School of Electrical Engineering and Computer Science and Digital Futures KTH Royal Institute of Technology Stockholm Sweden Department of Control Science and Engineering College of Electronics and Information Engineering Shanghai Research Institute for Intelligent Autonomous Systems Institute for Advanced Study Tongji University Shanghai China State Key Laboratory of Synthetical Automation for Process Industries Northeastern University Shenyang China School of Electrical and Electronic Engineering Nanyang Technological University Singapore Singapore

This paper considers online convex optimization with long term constraints, where constraints can be violated in intermediate rounds, but need to be satisfied in the long run. The cumulative constraint violation is used as the metric to measure constraint violations, which excludes the situation that strictly feasible constraints can compensate the effects of violated constraints. A novel algorithm is first proposed and it achieves an O(Tmax{c,1-c}) bound for static regret and an O(T (1-c)/2) bound for cumulative constraint violation, where c ϵ (0, 1) is a user-defined trade-off parameter, and thus has improved performance compared with existing results. Both static regret and cumulative constraint violation bounds are reduced to O(log(T )) when the loss functions are strongly convex, which also improves existing results. In order to achieve the optimal regret with respect to any comparator sequence, another algorithm is then proposed and it achieves the optimal O( p T (1 + PT )) regret and an O(√T) cumulative constraint violation, where PT is the path-length of the comparator sequence. Finally, numerical simulations are provided to illustrate the effectiveness of the theoretical results. Copyright © 2021, The Authors. All rights reserved.

关键词： Comparators (optical)

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Off-Policy Q-Learning for Anti-Interference control of Multi-Player Systems ⁎

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IFAC-PapersOnLine 2020年第2期53卷 9189-9194页

作者： Jinna Li Zhenfei Xiao Tianyou Chai Frank. L. Lewis Sarangapani Jagannathan School of Information and Control Engineering Liaoning Shihua University Fushun 113001 China State Key Laboratory of Synthetical Automation for Process Industries Northeastern University Shenyang 110819 China UTA Research Institute the University of Texas at Arlington Arlington TX 76118 USA Department of Electrical and Computer Engineering Missouri University of Science and Technology Rolla MO 65409 USA

This paper develops a novel off-policy game Q-learning algorithm to solve the anti-interference control problem for discrete-time linear multi-player systems using only data without requiring system matrices to be known. The primary contribution of this paper lies in that the Q-learning strategy employed in the proposed algorithm is implemented in an off-policy policy iteration approach other than on-policy learning due to the well-known advantages of off-policy Q-learning over on-policy Q-learning. All of the players work hard together for the goal of minimizing their common performance index meanwhile defeating the disturbance that tries to maximize the specific performance index, and finally they reach the Nash equilibrium of the game resulting in satisfying disturbance attenuation condition. In order to find the solution to the Nash equilibrium, the anti-interference control problem is first transformed into an optimal control problem. Then an off-policy Q-learning algorithm is proposed in the framework of typical adaptive dynamic programming (ADP) and game architecture, such that control policies of all players can be learned using only measured data. Comparative simulation results are provided to verify the effectiveness of the proposed method.

关键词： H ∞ control off-policy Q-learning game theory Nash equilibrium

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Development of a smart identification and sorting system

Development of a smart identification and sorting system

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2018 World Congress on Engineering and Computer Science, WCECS 2018

作者： Kumar, Shubham Ashi Khanna, Pradeep Department of Instrumentation and Control Netaji Subhas Institute of Technology New Delhi India Department of Manufacturing Process and Automation Engineering South Africa

ISBN: (纸本)9789881404909

Sorting of the components on the basis of their features is an important process extensively required in industries mainly on assembly and production lines. Such systems are of significant importance in selective assembly processes where the part to be delivered is decided on the basis of real time requirements. This not only does away with the requirement of manual labor, but also addresses the issue of mistakes arising from fatigue and negligence of human worker, plus there is definitely an increase in productivity by the use of such systems as they offer the advantage of complete automation of the process. The present system has been developed with a view to provide an effective, simple and low cost solution to identification and sorting system applications. The system has been developed by using less costly and robust sensors and actuators such that the electronic circuitry involved is also simple and can meet the demands where flexibility of a concern because the present system can quickly be reprogrammed to meet any changed circumstance within the operating range of the system. System presently developed is based on sorting on the basis of component color. The system does not need to hit its home position each time it makes a delivery, rather it takes its present position as the reference and can make a quick move to the next delivery, saving a significant time. The system has successfully been tested and is found to give an error less than 1% in total number of trials conducted. © 2018 Newswood Limited. All rights reserved.

关键词： Real time systems

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A Primal-Dual SGD Algorithm for Distributed Nonconvex Optimization

arXiv

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arXiv 2020年

作者： Yi, Xinlei Zhang, Shengjun Yang, Tao Chai, Tianyou Johansson, Karl H. The Division of Decision and Control Systems School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Stockholm100 44 Sweden The Department of Electrical Engineering University of North Texas DentonTX76203 United States The State Key Laboratory of Synthetical Automation for Process Industries Northeastern University Shenyang110819 China

The distributed nonconvex optimization problem of minimizing a global cost function formed by a sum of n local cost functions by using local information exchange is considered. This problem is an important component of many machine learning techniques with data parallelism, such as deep learning and federated learning. We propose a distributed primal–dual stochastic gradient descent (SGD) algorithm, suitable for arbitrarily connected communication networks and any smooth (possibly nonconvex) cost functions. We show that the proposed algorithm achieves the linear speedup convergence rate O(1/√nT) for general nonconvex cost functions and the linear speedup convergence rate O(1/(nT)) when the global cost function satisfies the Polyak–Lojasiewicz (P–L) condition, where T is the total number of iterations. We also show that the output of the proposed algorithm with constant parameters linearly converges to a neighborhood of a global optimum. We demonstrate through numerical experiments the efficiency of our algorithm in comparison with the baseline centralized SGD and recently proposed distributed SGD algorithms. Copyright © 2020, The Authors. All rights reserved.

关键词： Cost functions

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Sliding Mode control of Uncertain Switched Systems with Partly Known Sojourn Probabilities

Sliding Mode Control of Uncertain Switched Systems with Part...

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Asian control Conference

作者： Haijuan Zhao Yugang Niu Yuanyuan Zou The Key Laboratory of Advanced Control and Optimization for Chemical Process East China University of Science and Technology Key Laboratory of System Control and Information Processing Department of Automation Shanghai Jiao Tong University Shanghai China

ISBN: (纸本)9781728102634

This paper is concerned with the sliding mode control (SMC) problem for a class of uncertain switched systems subject to partly known sojourn probabilities. The sojourn probability is the probability of a switched system staying in each subsystem, which may be available or unavailable. A key issue is how to design a sliding mode controller to guarantee the stability performance of the reconstructed switched systems subject to the partly known sojourn probabilities. To this end, by using a set of stochastic variables, the switched system model is reconstructed with partly known sojourn probabilities. And then, the sliding mode control law is constructed to ensure the reachability of the designed common sliding surface. Furthermore, the sufficient condition is derived to ensure the mean-square stability of the closed-loop system under the partly unknown sojourn probabilities. Finally, a numerical example is provided to illustrate the proposed method.

关键词： Switched systems Switches Closed loop systems Stability analysis Sliding mode control Trajectory

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Automatic decision-making system for the desalinization of water for irrigation

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IOP Conference Series: Earth and Environmental Science 2020年第1期614卷

作者： R Gaziyeva E Ozodov E Bozorov A Nigmatov Department of Automation and Control of Technology Process Tashkent Institute of Irrigation and Agricultural Mechanization Engineers 39 Koriy-Niyoziy 100000 Tashkent Uzbekistan

The high salinity of water negatively affects soil fertility up to yield loss. In regions with high salinity, unorthodox methods and devices are used to lower the level of mineralization. This article discusses the use of an automatic decision-making system for a device to lower the level of mineralization by diffusion mixing. Construction able to filter water to irrigation rates up to 3 grams per liter and extent the operating period of reverse osmosis. The article provides a detailed description algorithm of a program for automatic control of the water purification process based on the Atmega 328 processor.

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Predictive control for Continuous Stirred Tank Reactors

Predictive Control for Continuous Stirred Tank Reactors

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2019 International Conference on Informatics, control and Robotics 2019信息学、控制和机器人学国际会议(ICICR2019)

作者： Ioana NASCU Ioan NASCU Wen-li DU Sai GU Key Laboratory of Advanced Control and Optimization for Chemical Processes Ministry of Education East China University of Science and Technology Department of Chemical and Process Engineering University of Surrey Department of Automation Technical University of Cluj-Napoca

The paper focuses on the implementation of a model based predictive control(MBPC) method, for Continuous Stirred Tank Reactors. First, the modelling problem of a single irreversible exothermic reaction, taking place in a perfectly mixed continuously stirred tank reactor(CSTR) is presented. The dynamic model consists of differential material and energy balance equations. The control strategy is investigated and evaluated by performing simulations and analyzing the results. The disturbance rejection capacity of the control system(regulatory control performances) have been tested and compared with those obtained using a classical Proportional Integral Derivative(PID) based controller. The results show that this control strategy has good performances and can be efficiently used to control the CSTR.

关键词： Predictive control PID control Chemical reactor process model

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Sliding Mode control for Networked control System Under Fading Channels

Sliding Mode Control for Networked Control System Under Fadi...

引用

control technology and Applications (CCTA),

作者： Jiarui Li Yugang Niu Yuanyuan Zou Key Laboratory of Advanced Control and optimization for Chemical Process (East China University of Science and Technology) Ministry of Education Shanghai China Department of Automation Shanghai Jiao Tong University Shanghai China

In this work, the discrete-time sliding mode control problem for the networked control systems under fading channels is investigated. Moreover, the state signals will be quantized through a logarithmic quantizer before transmitted to the controller. Subsequently, a sliding surface relating to fading coefficient is designed to cope with the fading measurements. It is shown that the designed sliding mode controller can drive the state trajectories into the neighborhood of the specified sliding surface and the closed-loop system is asymptotically stable in the sense of mean square. In the end, a numerical simulation is given.

关键词： Fading channels Quantization (signal) Symmetric matrices Sliding mode control Closed loop systems Lyapunov methods Networked control systems

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U-model enhanced control of Volterra series systems

U-model enhanced control of Volterra series systems

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第三十八届中国控制会议

作者： Quanmin Zhu Weicun Zhang Jing Chen Department of Engineering Design and Mathematics University of the West of England School of Automation and Electrical Engineering University of Science and Technology Beijing Key Laboratory of Advanced Process Control for Light Industry Jiangnan University

This study expands the U-model based control(U-control in short) concept and formulation, a universal model-independent framework for designing control systems, into Volterra series modelled nonlinear systems. With this framework, various Volterra series control schemes can be universally achieved with relative concise/general formulation. In techniques, this study takes U-model structure to realise U-Volterra series model conversion for model inversion and designs the invariant linear stable controller in a feedback loop to lay a basis for specifying system transient and steady state performances. Heuristically, a bench test example is used to demonstrate the effectiveness of the design procedure, as well as the routines in applications.

关键词： U-model based control U-control dynamic inversion Volterra series systems simulation studies

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