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Multi-objective optimal chemotherapy control model for cancer treatment

MEDICAL & BIOLOGICAL ENGINEERING & COMPUTING 2011年第1期49卷 51-65页

作者： Algoul, S. Alam, M. S. Hossain, M. A. Majumder, M. A. A. Univ Bradford Dept Comp Bradford BD7 1DP W Yorkshire England Univ Dhaka Dept Appl Phys Elect & Commun Engn Dhaka 1000 Bangladesh Univ Bradford Sch Life Sci Bradford BD7 1DP W Yorkshire England

This article presents an investigation into the development of a multi-objective optimal chemotherapy control model to reduce the number of cancer cells after a number of fixed treatment cycles with minimum side effects. Mathematical models for cancer chemotherapy are designed to predict the number of tumour cells and control the tumour growth during treatment. This requires an understanding of the system in the absence of treatment and a description of the effects of the treatment. In order to achieve multi-objective optimal control model, we used the proportional, integral and derivative (PID) and I-PD (modified PID with Integrator used as series) controllers based on Martin's model for drug concentration. To the best of our knowledge, this is the first PID/IPD-based optimal chemotherapy control model used to investigate the cancer treatment. The proposed control schemes are designed based on the optimal solution of three objective functions, which include (i) maximising tumour cell killing, for (ii) minimum toxicity, and (iii) tolerable drug concentration. Multi-objective genetic algorithm (MOGA) is used to find suitable parameters of controllers that trade-off among design objectives considered in this work. The results of the different optimal scheduling patterns of the proposed models are presented and discussed through a set of experiments. Finally, the observations are compared with the existing models in order to demonstrate the merits and capabilities of the proposed multi-objective optimisation models. It is noted that the proposed model offers best performance as compared to any models reported earlier.

关键词： Cancer chemotherapy Drug scheduling Tumour growth control algorithm Optimisation

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Decentralized Cooperative Collision Avoidance control for Unmanned Rotorcraft with Bounded Acceleration

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JOURNAL OF GUIDANCE control AND DYNAMICS 2018年第11期41卷 2445-2454页

作者： Rodriguez-Seda, Erick J. Dawkins, Jeremy J. US Naval Acad Dept Weap & Syst Engn Annapolis MD 21402 USA

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control of a Free-Flying Space Manipulation Robot with a Payload

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AUTOMATION AND REMOTE control 2023年第10期84卷 1079-1087页

作者： Rutkovskii, V. Yu. Glumov, V. M. Russian Acad Sci Trapeznikov Inst Control Sci Moscow Russia

The control modes of a free-flying space manipulation robot during the transportation and installation of a building element on a large space structure are considered. It is proposed to save the working fluid of the gas-jet engines of the robot body when moving along the trajectory by using the mobility of a manipulator with electromechanical drives for the angular stabilization of the mechanical "robot-transported element" system. Conditions ensuring the stable motion of the manipulator in the working area when installing the element on the assembled structure are obtained. A stability domain is determined to select the initial configuration of the manipulator before installing the element and its admissible change during installation. The control algorithms are designed based on the principle of dynamic feedback systems.

关键词： free-flying space manipulation robot working area technical controllability control algorithm motion stability

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Fuzzy based variable step approaching digital control for plants with time delay

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ISA TRANSACTIONS 1998年第3期37卷 167-176页

作者： Li, GM Tsang, KM Ho, SL Hong Kong Polytech Univ Dept Elect Engn Kowloon Hong Kong

A simple digital controller named Variable Step Approaching Digital controller (VSADC) based on fuzzy concept is proposed for plants with time delay. The proposed controller is basically a modified Takagi-Sugeno Type Fuzzy controller and can be represented by a compact analytical equation with only several adjustable parameters. The tuning rule and self tuning scheme in constant value control are developed. Detailed simulation investigation is carried out. Verification experiment using Process Trainer PT326 heating system as testbed is conducted. The proposed controller is compared with PID controller tuned by well-known Ziegler and Nicliols's ultimate cycle method. Both simulation and experimental results show that the proposed VSADC is effective in suppressing overshoot and in attenuating decaying oscillation cycles. It is also superior to PID controller in the control of plants with dominant time delay. (C) 1998 Elsevier Science Ltd. All rights reserved.

关键词： fuzzy control digital control process control time delay control algorithm

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Spacecraft Momentum Dumping Using Fewer than Three External control Torques

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JOURNAL OF GUIDANCE control AND DYNAMICS 2009年第1期32卷 242-247页

作者： Karami, M. A. Sassani, F. Virginia Polytech Inst & State Univ Dept Engn Sci & Mech Blacksburg VA 24061 USA Univ British Columbia Vancouver BC V6T 1Z4 Canada

Momentum wheels are used in spacecraft attitude control systems to stabilize the attitude of the spacecraft. Disturbance torques on the spacecraft increase its angular momentum and speed up the momentum wheels. The angular momentum stored in the momentum wheels needs to be removed by implementing external torques to prevent saturation. control algorithms are developed in this paper that remove the accumulated angular momentum, despite the loss of external control torque about one or even two of the principal axes of the spacecraft due to failures. The procedure consists of three stages. First, the angular speed of the momentum wheels corresponding to the unactuated axes is removed by performing attitude maneuvers. The angular momentum stored in the remaining wheels is then dumped using a conventional momentum-dumping method. Finally, the desired attitude of the spacecraft is restored. Numerical simulations demonstrate the successful and smooth performance of the proposed control algorithm and the control laws involved.

关键词： Spacecrafts Numerical Simulation control algorithm Spacecraft Attitude Quaternions Pulse Width Modulation Satellites Attitude Stabilization Flywheels

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Optimal torque control of permanent magnet synchronous motors using adaptive dynamic programming

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IET POWER ELECTRONICS 2020年第12期13卷 2442-2449页

作者： Khiabani, Ataollah Gogani Heydari, Ali Southern Methodist Univ Dept Mech Engn 6425 Boaz Lane Dallas TX 75205 USA

In this study, a new approach based on adaptive dynamic programming (ADP) is proposed to control permanent magnet synchronous motors (PMSMs). The objective of this study is to control the torque and consequently the speed of a PMSM when an unknown load torque is applied to it. The proposed controller achieves a fast transient response, low ripples and small steady-state error. The control algorithm uses two neural networks, called critic and actor. The former is utilised to evaluate the cost and the latter is used to generate control signals. The training is done once offline and the calculated optimal weights of actor network are used in online control to achieve fast and accurate torque control of PMSMs. This algorithm is compared with field oriented control (FOC) and direct torque control based on space vector modulation. Simulations and experimental results show that the proposed algorithm provides desirable results under both accurate and uncertain modelled dynamics. Although the performance of FOC method is comparable with ADP under nominal conditions, the torque and speed response of ADP is better than FOC under realistic scenarios, that is, when parameter uncertainties exist.

关键词： angular velocity control transient response torque control synchronous motor drives dynamic programming synchronous motors machine vector control permanent magnet motors actor network online control direct torque control uncertain modelled dynamics ADP optimal torque control permanent magnet synchronous motors adaptive dynamic programming unknown load torque fast transient response steady-state error control algorithm control signals optimal weights PMSM

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Smooth LMS-based adaptive control of SPV system tied to grid for enhanced power quality

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IET POWER ELECTRONICS 2020年第15期13卷 3456-3466页

作者： Verma, Pallavi Garg, Rachana Mahajan, Priya Delhi Technol Univ Dept Elect Engn Bawana Rd Delhi 110042 India

In this study, a novel smooth least mean square (LMS) algorithm for controlling PV inverter has been proposed to estimate the reference current for synchronisation of solar photovoltaic (SPV) to the grid. The proposed control extracts both active and reactive fundamental components of the load current with improved convergence rate. These currents are compared with sensed grid currents to generate gating pulses for a voltage source converter. It also compensates the load harmonics, reduces voltage fluctuation at point of common coupling and supplies the reactive power demand of the local load. The algorithm has been tested under steady state and transient conditions for input variation as well as load variation under the power factor correction mode of operation. The algorithm has been developed in MATLAB/Simulink. Further, the efficacy of the proposed control algorithm has been tested on prototype hardware setup developed in the laboratory using dSPACE1104. The total harmonic distortion at the grid side, obtained from simulated and hardware results are well within the IEEE standards.

关键词： power system harmonics voltage control electric current control power factor correction adaptive control harmonic distortion power supply quality invertors photovoltaic power systems power grids input variation load variation control algorithm smooth LMS-based adaptive control SPV system enhanced power quality novel smooth least mean square algorithm controlling PV inverter solar photovoltaic control extracts reactive fundamental components improved convergence rate sensed grid currents gating pulses voltage source converter load harmonics voltage fluctuation reactive power demand local load steady state transient conditions

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GUARANTEED PERFORMANCE control OF NONLINEAR-SYSTEMS WITH APPLICATION TO FLEXIBLE SPACE STRUCTURE

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JOURNAL OF GUIDANCE control AND DYNAMICS 1995年第1期18卷 143-150页

作者： SONG, YD North Carolina Agricultural and Technical State Univ. Greensboro

This paper considers the problem of controlling nonlinear uncertain systems arising from flexible aerospace structures, We begin by addressing the tracking problem for a class of nonlinear dynamic systems with modeling uncertainties and external disturbances, New control algorithms that accommodate modeling uncertainties are proposed, It is shown that these algorithms not only guarantee system stability but also achieve certain bounded performance index and are readily applicable in vibration suppression of large flexible space structures, Numerical verification of the proposed strategy is demonstrated via the lumped mass model of a hypersonic aerospace night vehicle structure.

关键词： Large Space Structures Mathematical Models control algorithm Vibration Suppression Flight Vehicle Stiffness Matrices Feedback control Linear System Theory Second Order Differential Equations Structural Dynamics

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Continuous traditional and high-order sliding modes for satellite formation control

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JOURNAL OF GUIDANCE control AND DYNAMICS 2005年第4期28卷 826-831页

作者： Massey, T Shtessel, Y Sci Applicat Int Corp Huntsville AL 35806 USA Univ Alabama Huntsville AL 35899 USA

This Note focuses on continuous traditional and high-order sliding mode control for controlling the motion of one satellite as it follows a defined path around another satellite that is orbiting the Earth robustly to model uncertainties and external disturbances. The problem with any satellite formation control is that all orbiting bodies are subject to forces that tend to force the satellites out of their stable Keplerian orbits. These forces include gravitational perturbations, atmospheric drag, and solar radiation pressure. Recently Yeh et al. defined an effective robust method of controlling satellites using sliding mode control (SMC)4 while minimizing fuel consumption.

关键词： Satellite Formation Sliding Mode control Pulse Width Modulation Fuel Consumption Earth Atmospheric Drag Solar Radiation Single Input Single Output Amplitude control control algorithm

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control OF A FLEXIBLE SPACE ROBOT EXECUTING A DOCKING MANEUVER

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JOURNAL OF GUIDANCE control AND DYNAMICS 1995年第4期18卷 756-766页

作者： CHEN, Y MEIROVITCH, L Virginia Polytechnic Institute and State University Blacksburg Virginia 24061

This paper is concerned with a flexible space robot executing a docking maneuver with a target whose motion is not known a priori. The dynamical equations of the space robot are first derived by means of Lagrange's equations and then separated into two sets of equations suitable for rigid body maneuver and vibration suppression control. For the rigid-body maneuver, on-line feedback tracking control is carried out by means of an algorithm based on Lyapunov-like methodology and using on line measurements of the target motion. For the vibration suppression, LQR feedback control in conjunction with disturbance compensation is carried out by means of collocated sensor/actuator pairs dispersed along the flexible arms. Problems related to the digital implementation of the control algorithms, such as the bursting phenomenon and system instability, are discussed and a modified discrete-time control scheme is developed. A numerical example demonstrates the control algorithms.

关键词： Flexible Space Robots Linear Quadratic Regulator control algorithm Vibration Suppression Actuators Sensors Feedback control Free Flying Robots Flexible Manipulators Vibration control

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