INTERVENTION IN BIOLOGICAL PHENOMENA REPRESENTED BY GENETIC REGULATORY NETWORKS: A VARIABLE STRUCTURE APPROACH

2012 ◽  
Vol 20 (04) ◽  
pp. 327-347
Author(s):  
MOHAMED AMINE FNAIECH ◽  
HAZEM N. NOUNOU ◽  
MOHAMED N. NOUNOU ◽  
ANIRUDDHA DATTA

The utilization of mathematical tools in the analysis and synthesis of models representing biological phenomena is rapidly growing. Adding to these efforts, in this paper, a mathematical method based on the sliding mode control approach will be used for the purpose of developing a therapeutic intervention strategy for a class of biological phenomena. Such an intervention scheme aims at moving an undesirable state of a diseased network towards a more desirable state using drugs to act on some genes/metabolites that characterize the undesirable behavior. S-systems, which offer a good compromise between accuracy and mathematical flexibility, are a promising framework for modeling the dynamical behavior of biological phenomena as well as genetic regulatory networks. Since biological phenomena modeled by S-systems are complex nonlinear processes, the need for robust nonlinear intervention strategies that are capable of guiding the target variables to their desired values often arises. The main objective of this paper is to develop an intervention scheme based on sliding mode control theory, sometimes referred to as variable structure control theory, and evaluate the robustness of the sliding mode intervention scheme in the presence of model parameter uncertainties. The proposed intervention strategy is applied to a glycolytic-glycogenolytic pathway model and the simulation results demonstrate the effectiveness of the proposed scheme.

2021 ◽  
Vol 54 (3-4) ◽  
pp. 360-373
Author(s):  
Hong Wang ◽  
Mingqin Zhang ◽  
Ruijun Zhang ◽  
Lixin Liu

In order to effectively suppress horizontal vibration of the ultra-high-speed elevator car system. Firstly, considering the nonlinearity of guide shoe, parameter uncertainties, and uncertain external disturbances of the elevator car system, a more practical active control model for horizontal vibration of the 4-DOF ultra-high-speed elevator car system is constructed and the rationality of the established model is verified by real elevator experiment. Secondly, a predictive sliding mode controller based on adaptive fuzzy (PSMC-AF) is proposed to reduce the horizontal vibration of the car system, the predictive sliding mode control law is achieved by optimizing the predictive sliding mode performance index. Simultaneously, in order to decrease the influence of uncertainty of the car system, a fuzzy logic system (FLS) is designed to approximate the compound uncertain disturbance term (CUDT) on-line. Furthermore, the continuous smooth hyperbolic tangent function (HTF) is introduced into the sliding mode switching term to compensate the fuzzy approximation error. The adaptive laws are designed to estimate the error gain and slope parameter, so as to increase the robustness of the system. Finally, numerical simulations are conducted on some representative guide rail excitations and the results are compared to the existing solution and passive system. The analysis has confirmed the effectiveness and robustness of the proposed control method.


2013 ◽  
Vol 846-847 ◽  
pp. 134-138
Author(s):  
Jue Wang ◽  
Fei Li ◽  
Ye Huang ◽  
Jian Hao Wang ◽  
Hong Lin Zhang

The paper studies the problem of tracking control for flight simulator servo systems, one typical CPS, with parameter uncertainties and nonlinear friction compensation. Methods of adaptive global sliding mode control and backstepping control are respectively proposed to realize the control of virtual rotational speed and position tracking. Adaptive backstepping global sliding mode control strategy for flight simulator servo systems is proposed and its stability is analyzed. Simulation results show the effectiveness of the proposed method, which could achieve the precision position tracking performance and eliminate the chattering.


Author(s):  
Lijun Han ◽  
Guoyuan Tang ◽  
Ruikun Xu ◽  
Hui Huang ◽  
De Xie

In this paper, a fractional integral sliding mode control (FISMC) strategy with a disturbance observer (DO) is proposed for the trajectory tracking problem of the underwater manipulator, under lumped disturbances namely parameter uncertainties and external disturbances. The modified fractional integral sliding mode surface (FISMS) is designed to guarantee the fast convergence of system states. The DO method and the second-order sliding mode control law are used in the controller design, in which the former is introduced to compensate the effect of the lumped disturbances. Also, a saturated function is selected to replace the sign function to attenuate the chattering phenomenon. The stability of the overall closed-loop system is proved via Lyapunov’s finite-time stability theory. Numerical simulations are performed on a 6 degree of freedom (DOF) underwater manipulator. Simulation results demonstrate that the proposed control scheme can achieve better tracking performance and stronger robustness against disturbances, by comparing with the DO-based PD control and the DO-based PID-type linear sliding mode control (SMC).


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