scholarly journals The Nonfragile Controller with Covariance Constraint for Stable Motion of Quadruped Search-Rescue Robot

2014 ◽  
Vol 6 ◽  
pp. 917381 ◽  
Author(s):  
Peng Wang ◽  
Jixiang Li ◽  
Yuan Zhang

The problem of a stable motion for the quadruped search-rescue robots is described as a variance constrained uncertainty in the discrete systems. According to the model structure of the quadruped search-rescue robot, the kinematics of the robot is analyzed on the basis of the D- H parameter. Each joint of the robot angular velocity is planned using the Jacobian matrix, because the angular velocity is directly related to the stability of walking based on the ADAMS simulation. The nonfragile control method with the covariance constraint is proposed for the gait motion control of the quadruped search-rescue robot. The motion state feedback controller and the covariance upper bounds can be given by the solutions of the linear matrix inequalities (LMI), which makes the system satisfy the covariance constrain theory. The results given by LMI indicate that the proposed control method is correct and effective.

Author(s):  
Gao Ming-Zhou ◽  
Chen Xin-Yi ◽  
Han Rong ◽  
Yao Jian-Yong

To suppress airfoil flutter, a lot of control methods have been proposed, such as classical control methods and optimal control methods. However, these methods did not consider the influence of actuator faults and control delay. This paper proposes a new finite-time H∞ adaptive fault-tolerant flutter controller by radial basis function neural network technology and adaptive fault-tolerant control method, taking into account actuator faults, control delay, modeling uncertainties, and external disturbances. The theoretic section of this paper is about airfoil flutter dynamic modeling and adaptive fault-tolerant controller design. Lyapunov function and linear matrix inequality are employed to prove the stability of the proposed control method of this paper. The numeral simulation section further proves the effectiveness and robustness of the proposed control algorithm of this paper.


Author(s):  
Daren Yu ◽  
Xiaofeng Liu ◽  
Wen Bao ◽  
Zhiqiang Xu

The multiobjective regulating and protecting control method presented here will enable improved control of multiloop switching control of an aeroengine. The approach is based on switching control theory, the switching performance objectives and the strategy are given, and a family of H∞ proportional-integral-derivative controllers was designed by using linear matrix inequality optimization algorithm. The simulation shows that using the switching control design method not only can improve the dynamic performance of the engine control system but also can guarantee the stability in some peculiar occasions.


2016 ◽  
Vol 2016 ◽  
pp. 1-11
Author(s):  
Fengjiao Wu ◽  
Guitao Zhang ◽  
Zhengzhong Wang

The robust fuzzy control for fractional-order hydroturbine regulating system is studied in this paper. First, the more practical fractional-order hydroturbine regulating system with uncertain parameters and random disturbances is presented. Then, on the basis of interval matrix theory and fractional-order stability theorem, a fuzzy control method is proposed for fractional-order hydroturbine regulating system, and the stability condition is expressed as a group of linear matrix inequalities. Furthermore, the proposed method has good robustness which can process external random disturbances and uncertain parameters. Finally, the validity and superiority are proved by the numerical simulations.


Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Saleem Riaz ◽  
Hui Lin ◽  
Farkhanda Afzal ◽  
Ayesha Maqbool

An iterative learning robust fault-tolerant control algorithm is proposed for a class of uncertain discrete systems with repeated action with nonlinear and actuator faults. First, by defining an actuator fault coefficient matrix, we convert the iterative learning control system into an equivalent unknown nonlinear repetitive process model. Then, based on the mixed Lyapunov function approach, we describe the stability of the nonlinear repetitive mechanism on time and trial indices and have appropriate conditions for the repeated control system’s stability in terms of linear matrix inequality theory. Through LMI techniques, we have obtained satisfactory results and controller stability, and robustness against fault tolerance is also discussed in detail. Finally, the simulation results of the output tracking control of the two exemplary models verify the effectiveness of the proposed algorithm.


2013 ◽  
Vol 834-836 ◽  
pp. 1229-1233
Author(s):  
Bin Zhang

This paper researches a fuzzy control method for passive flexible joint robot. Stability control method applying T-S fuzzy model is employed for single-link flexible joint robot. T-S fuzzy model is used to approximate the flexible joint robot firstly, and then fuzzy controller is developed based on the principle of parallel distributed compensation. The fuzzy controller is also applied to the passive properties of model error. The stability conditions are proposed by Lyapunov function and linear matrix inequalities are also applied to solve the controller parameters. Simulation results show that the proposed method of application value.


2021 ◽  
pp. 107754632199759
Author(s):  
Peng Chen ◽  
Bin Wang ◽  
Yuqiang Tian ◽  
Ying Yang

This article mainly studies the Mittag–Leffler stability and finite-time control of a time-delay fractional-order hydraulic turbine governing system. First, properties of the Riemann–Liouville derivative and some important lemmas are introduced. Second, considering the mechanical time delay of the main servomotor, the mathematical model of a fractional-order hydraulic turbine governing system with mechanical time delay is presented. Then, based on Mittag–Leffler stability theorem, a suitable sliding surface and finite-time controller are designed for the hydraulic turbine governing system. The system stability is confirmed, and the stability condition is given in the form of linear matrix inequalities. Finally, the traditional proportional–integral–derivative control method and an existing sliding mode control method are selected to verify the effectiveness and robustness of the proposed method. This study also provides a new approach for the stability analysis of the time-delay fractional-order hydraulic turbine governing system.


2011 ◽  
Vol 80-81 ◽  
pp. 1096-1102 ◽  
Author(s):  
Duo Qing Sun

All-coefficient golden section adaptive control scheme for attitude keeping of spacecraft with unknown parameters is proposed in this paper. Based on Lyapunov’s direct method for time-variant discrete systems, the paper gives the conditions for the uniform asymptotic stability of the all-coefficient golden section adaptive control system. The given conditions are dependent on the relations between coefficients in the closed-loop system equations and the variable rates of the coefficients. The result in this paper can be used to analyze quantitatively the stability of multivariable time-variant discrete systems. Thus, a theoretical foundation is established to apply the golden section adaptive control method to control specific spacecraft.


Electronics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 593
Author(s):  
Kun Yuan ◽  
Zhetong Ding ◽  
Yaping Li ◽  
Mingyu Huang ◽  
Kaifeng Zhang

Recently, demand-side resources (DSRs) have proceeded to participate in frequency control of the power systems. Compared with traditional generation-side resources, DSRs have unique intermittent characteristics. Taking aggregation of air conditions as an example, they must take a break after providing power support for a period of time considering the user comfort. This behavior, known as the intermittent characteristic, obviously affects the stability of the power systems. Therefore, this paper designs a corresponding controller for DSRs based on the intermittent control method. The designed controller is incorporated into the traditional load frequency control (LFC) system. The time delay is also considered. A rigorous stability proof and the robust H ∞ performance analysis is presented for the new LFC system. Then, the sufficient robust frequency stabilization result is presented in terms of linear matrix inequalities (LMIs). Finally, a two-area power system is provided to illustrate the obtained results. The results show that the designed intermittent controller can mitigate the impact of intermittent characteristics of DSRs.


2021 ◽  
Vol 11 (6) ◽  
pp. 2833
Author(s):  
Wen-Jer Chang ◽  
Ming-Hsuan Tsai ◽  
Chin-Lin Pen

This paper investigates the observer-based fuzzy controller design method for nonlinear discrete-time singular systems that are represented by Takagi-Sugeno (T-S) fuzzy models. At first, the nonlinearity can be well-approximated with several local linear input-output relationships. The parallel distributed compensation (PDC) technology and the proportional derivative (PD) feedback scheme are then employed to construct the observer-based fuzzy controller. To solve the problem of unmeasured states, the impulsive phenomenon of singular systems, and the PD scheme’s reasonableness, a novel observer-based fuzzy controller is developed. By using the Lyapunov theory and projection lemma, the stability criteria are built in terms of linear matrix inequalities (LMI). Moreover, the gains of fuzzy controller and fuzzy observer can be calculated synchronously by using convex optimization algorithms. Finally, a biological economic system is provided to verify the effectiveness of the proposed fuzzy control method.


Author(s):  
Fatemeh Khani ◽  
Mohammad Haeri

Industrial processes are inherently nonlinear with input, state, and output constraints. A proper control system should handle these challenging control problems over a large operating region. The robust model predictive controller (RMPC) could be an linear matrix inequality (LMI)-based method that estimates stability region of the closed-loop system as an ellipsoid. This presentation, however, restricts confident application of the controller on systems with large operating regions. In this paper, a dual-mode control strategy is employed to enlarge the stability region in first place and then, trajectory reversing method (TRM) is employed to approximate the stability region more accurately. Finally, the effectiveness of the proposed scheme is illustrated on a continuous stirred tank reactor (CSTR) process.


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