Adaptive robust control of cancer chemotherapy in the presence of parametric uncertainties: A comparison between three hypotheses

2015 ◽  
Vol 56 ◽  
pp. 145-157 ◽  
Author(s):  
Hamed Moradi ◽  
Mojtaba Sharifi ◽  
Gholamreza Vossoughi
Keyword(s):  
Robust Control ◽  
Cancer Chemotherapy ◽  
Adaptive Robust Control ◽  
Parametric Uncertainties

scholarly journals Nonlinear Adaptive Robust Control of the Electro-Hydraulic Servo System

2020 ◽  
Vol 10 (13) ◽  
pp. 4494 ◽  
Author(s):  
Lijun Feng ◽  
Hao Yan
Keyword(s):  
Robust Control ◽  
Position Control ◽  
External Disturbance ◽  
Servo System ◽  
Adaptive Robust Control ◽  
Superior Performance ◽  
Parametric Uncertainties ◽  
State Equations ◽  
Hydraulic Servo ◽  
Hydraulic Servo System

This paper focuses on high performance adaptive robust position control of electro-hydraulic servo system. The main feature of the paper is the combination of adaptive robust algorithm with discrete disturbance estimation to cope with the parametric uncertainties, uncertain nonlinearities, and external disturbance in the hydraulic servo system. First of all, a mathematical model of the single-rod position control system is developed and a nonlinear adaptive robust controller is proposed using the backstepping design technique. Adaptive robust control is used to encompass the parametric uncertainties and uncertain nonlinearities. Subsequently, a discrete disturbance estimator is employed to compensate for the effect of strong external disturbance. Furthermore, a special Lyapunov function is formulated to handle unknown nonlinear parameters in the system state equations. Simulations are carried out, and the results validate the superior performance and robustness of the proposed method.

Integrated Direct/Indirect Adaptive Robust Control of Multi-DOF Hydraulic Robotic Arms

2007 ◽  
Author(s):  
Amit Mohanty ◽  
Bin Yao
Keyword(s):  
Parameter Estimation ◽  
Robust Control ◽  
Adaptive Robust Control ◽  
Least Square ◽  
Parametric Uncertainties ◽  
Robot Arm ◽  
Transient Performance ◽  
Seamless Integration ◽  
Output Tracking ◽  
Indirect Adaptive Robust Control

In a general DIARC framework [13], the emphasis is always on the guaranteed transient performance and accurate trajectory tracking in the presence of uncertain nonlinearity and parametric uncertainties along with accurate parameter estimation for secondary purpose such as system health monitoring and prognosis. Need for accurate parameter estimation calls for the use of Least Square Estimation (LSE) type of algorithms for such a seamless integration of good tracking performance and accurate parameter estimation. This paper presents a physical model based integrated direct/indirect adaptive robust control (DIARC) strategy for a hydraulically actuated 3-DOF robotic arm. To avoid the need of acceleration feedback for DIARC back-stepping design, the property, that the adjoint matrix and the determinant of the inertial matrix could be linearly parameterized by certain suitably selected parameters is utilized. Unlike gradient-type parameter estimation law, which used overparamterization, there is no multiple estimation of the single parameter. Theoretically, the resulting controller is able to take into account not only the effect of parametric uncertainties coming from the payload and various hydraulic parameters but also the effect of uncertain nonlinearities. Furthermore, the proposed DIARC controller guarantees a prescribed output tracking transient performance and final tracking accuracy while achieving asymptotic output tracking in the presence of parametric uncertainties only. Simulation results based on a three degree-of-freedom (DOF) hydraulic robot arm (a scaled down version of an industrial back-hoe/excavator arm) are presented to illustrate the proposed control algorithm.

Adaptive Robust Control Strategy for Coupled Parallel-Kinematics Piezo-Flexural Micro and Nano-Positioning Stages

2007 ◽  
Author(s):  
Saeid Bashash ◽  
Nader Jalili
Keyword(s):  
Robust Control ◽  
Sliding Mode Control ◽  
Tracking Control ◽  
Sliding Mode ◽  
Variable Structure ◽  
Adaptive Robust Control ◽  
Switching Function ◽  
Parametric Uncertainties ◽  
Parallel Kinematics ◽  
Axis Parallel

Multiple-axis parallel kinematics piezo-flexural stages, used in variety of scanning probe microscopy and manipulation applications, suffer not only from the hysteresis nonlinearity and the effects of system dynamics, but also from the nonlinear coupling of one axis action on the motion of the other axes. Motivated by these shortfalls, a Lyapunov-based adaptive robust control methodology is proposed for the simultaneous tracking control of multiple-axis parallel kinematics piezo-flexural micro/nano-positioning systems in the presence of parametric uncertainties and unknown or partially known hysteresis and coupling nonlinearities. For this, a double-axis parallel-kinematics piezo-flexural stage with sub-nanometer resolution capacitive position sensors is considered for the system analysis and controller verification. The hysteresis response and the coupling effect of the stage are studied through a number of experiments, followed by a mathematical formulation for the system nonlinear equation of motion. Adopting the variable structure (sliding mode) control method with a parameter adaptation strategy, an adaptive robust controller is then derived with its asymptotic stability guaranteed through the Lyapunov stability criterion. To avoid the chatter phenomenon, which is a common problem in the sliding mode control, the hard switching function of the controller is replaced by a soft switching function. Through theoretical analysis, it is demonstrated that a parallelogram-type zone of attraction can be explicitly formed for the proposed soft variable structure controller, to which the error phase trajectory converges. Therefore, a uniformly ultimately bounded closed-loop system response is achieved. The proposed controller is eventually implemented on the piezo-flexural stage, demonstrating the effective double-axis tracking control of the stage, even in the absence of a representative hysteresis model and despite parametric uncertainties. Results indicate good agreement between experiments and theoretical developments.

Adaptive Robust Control for Hydraulic Actuators With Disturbance Estimation

2015 ◽  
Author(s):  
Z. B. Xu ◽  
J. Y. Yao ◽  
Z. L. Dong ◽  
Y. Zheng
Keyword(s):  
Robust Control ◽  
Finite Time ◽  
Disturbance Observer ◽  
High Performance ◽  
Adaptive Robust Control ◽  
Parametric Uncertainties ◽  
Tracking Accuracy ◽  
Robust Controller ◽  
Hydraulic Actuators ◽  
Disturbance Estimation

In this paper, an adaptive robust control for hydraulic actuators with disturbance estimation is proposed for a hydraulic system with mismatched generalized uncertainties (e.g., parameter derivations, external disturbances, and/or unmodeled dynamics), in which a finite time disturbance observer and an adaptive robust controller are synthesized via backstepping method. The finite time disturbance observer is designed to estimate the mismatched generalized uncertainties. The adaptive robust controller is designed to handle parametric uncertainties and stabilize the closed loop system. The proposed controller accounts for not only the parametric uncertainties, but also the mismatched generalized uncertainties. Furthermore, the controller theoretically guarantees a prescribed tracking transient performance and final tracking accuracy while achieving asymptotic tracking performance after a finite time T0, which is very important for high accuracy tracking control of hydraulic servo systems. Simulation results are obtained to verify the high performance nature of the proposed control strategy.

Uniform robust exact differentiator-based output feedback adaptive robust control for DC motor drive systems

2020 ◽  
pp. 014233122097413
Author(s):  
Zhangbao Xu ◽  
Qingyun Liu ◽  
Xiaolei Hu
Keyword(s):  
Robust Control ◽  
Output Feedback ◽  
Control Method ◽  
Dc Motor ◽  
Adaptive Robust Control ◽  
Parametric Uncertainties ◽  
Servo Systems ◽  
Position Signal ◽  
Drive Systems ◽  
The Stability

This paper studies a high-accuracy motion control method named output feedback adaptive robust control for a dc motor with uncertain nonlinearities and parametric uncertainties, which always exist in physical servo systems and deteriorate their tracking performance. As only position signal is measurable, a uniform robust exact differentiator (URED) for the unmeasurable states and adaptive control for the parametric uncertainties are integrated in the model compensation term; and the robust control is applied to handle uncertain nonlinearities and stabilize the system. Then, the stability of the closed-loop system is proved theoretically. Finally, simulation and experimental results are studied for a dc motor system to prove the control performance of the proposed control method.

Energy-Efficient Adaptive Robust Control of Vector Thrust UAVs With Unknown Inertia Parameters

2018 ◽  
Author(s):  
Caiwu Ding ◽  
Lu Lu ◽  
Cong Wang
Keyword(s):  
Robust Control ◽  
Energy Efficient ◽  
Control Method ◽  
Thrust Force ◽  
Center Of Mass ◽  
Adaptive Robust Control ◽  
Parametric Uncertainties ◽  
Tracking Accuracy ◽  
Robust Tracking Control ◽  
Linear Equality Constraints

This paper proposes an energy-efficient adaptive robust tracking control method for a class of fully actuated, thrust vectoring unmanned aerial vehicles (UAVs) with parametric uncertainties including unknown moment of inertia, mass and center of mass, which would occur in aerial maneuvering and manipulation. We consider a novel vector thrust UAV with all propellers able to tilt about two perpendicular axes, so that the thrust force generated by each propeller is a fully controllable vector in 3D space, based on which an adaptive robust control is designed for accurate trajectory tracking in the presence of inertial parametric uncertainties and uncertain nonlinearities. Theoretically, the resulting controller achieves a guaranteed transient performance and final tracking accuracy in the presence of both parametric uncertainties and uncertain nonlinearities. In addition, in the presence of only parametric uncertainties, the controller achieves asymptotic output tracking. To resolve the redundancy in actuation, a thrust force optimization problem minimizing power consumption while achieving the desired body force wrench is formulated, and is shown to be convex with linear equality constraints. Simulation results are also presented to verify the proposed solution.

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