Considering that gravity on the ground alignment phase is different from that in space application phase, an adaptive backstepping sliding mode control method is proposed to achieve the attitude control and vibration ...
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ISBN:
(纸本)9781467374439
Considering that gravity on the ground alignment phase is different from that in space application phase, an adaptive backstepping sliding mode control method is proposed to achieve the attitude control and vibration suppression of the flexible spacecraft under different gravity environment. Fully considering the change of dynamic models, the sliding mode controller is designed according to the backstepping theory to control the flexible spacecraft under the influence of model and disturbances uncertainties, and the adaptive control laws are proposed to estimate the disturbances and gravity item online. The control strategy can guarantee the stability of the system based on the Lyapunov theory. The simulation results show that the controller is effective in attitude control and vibration suppression of the flexible spacecraft under different gravity environment, and has important value for theoretical research and engineering application.
An anti-saturation fault-tolerant adaptive torsional vibration control method with fixed-time prescribed performance for the rolling mill main drive system(RMMDS)was investigated,which is affected by control input sat...
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An anti-saturation fault-tolerant adaptive torsional vibration control method with fixed-time prescribed performance for the rolling mill main drive system(RMMDS)was investigated,which is affected by control input saturation,actuator faults,sensor measurement errors,and parameter ***,we gave a continuously differentiable saturation function to approximate the control input saturation characteristic of the RMMDS,translating the saturation characteristic into the matched uncertainty and unknown time-varying gain in the ***,an RMMDS mathematical model with unmatched uncertainty and unknown time-varying gain was developed,taking into account the presence of control input saturation,actuator faults,sensor measurement errors,and parameter *** on the established mathematical model,an error transformation model of the roll speed tracking was constructed by the equivalent error transformation *** to the error transformation model,a barrier Lyapunov function and a novel adaptive controller were studied to ensure that the roll speed tracking error always evolves inside a fixed-time asymmetric ***,numerical simulations were performed in Matlab/Simulink to verify the effectiveness and superiority of the proposed control method in suppressing the RMMDS torsional vibration.
Flatness pattern recognition is the key of the flatness control. The accuracy of the present flatness pattern recognition is limited and the shape defects cannot be reflected intuitively. In order to improve it, a nov...
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Flatness pattern recognition is the key of the flatness control. The accuracy of the present flatness pattern recognition is limited and the shape defects cannot be reflected intuitively. In order to improve it, a novel method via T-S cloud inference network optimized by genetic algorithm(GA) is proposed. T-S cloud inference network is constructed with T-S fuzzy neural network and the cloud model. So, the rapid of fuzzy logic and the uncertainty of cloud model for processing data are both taken into account. What's more, GA possesses good parallel design structure and global optimization characteristics. Compared with the simulation recognition results of traditional BP Algorithm, GA is more accurate and effective. Moreover, virtual reality technology is introduced into the field of shape control by lab VIEW, MATlab mixed programming. And virtual flatness pattern recognition interface is ***, the data of engineering analysis and the actual model are combined with each other, and the shape defects could be seen more lively and intuitively.
A new control strategy based on nonlinear unscented Kalman filter(UKF) is proposed for a neural mass model that serves as a model for simulating real epileptiform stereo-electroencephalographic (SEEG) signals. The UKF...
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A new control strategy based on nonlinear unscented Kalman filter(UKF) is proposed for a neural mass model that serves as a model for simulating real epileptiform stereo-electroencephalographic (SEEG) signals. The UKF is used as an observer to estimate the state from the noisy measurement because it has been proved to be effective for state estimation of nonlinear systems. A UKF controller is constructed via the estimated state and is illustrated to be effective for epileptiform spikes suppression of aforementioned model by numerical simulations.
Neural mass models can simulate the generation of electroencephalography(EEG) signals with different rhythms,and therefore the observation of the states of these models plays a significant role in brain research. Th...
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Neural mass models can simulate the generation of electroencephalography(EEG) signals with different rhythms,and therefore the observation of the states of these models plays a significant role in brain research. The structure of neural mass models is special in that they can be expressed as Lurie systems. The developed techniques in Lurie system theory are applicable to these models. We here provide a new observer design method for neural mass models by transforming these models and the corresponding error systems into nonlinear systems with Lurie form. The purpose is to establish appropriate conditions which ensure the convergence of the estimation error. The effectiveness of the proposed method is illustrated by numerical simulations.
The adaptive H_∞ control problem of multi-machine power system in the case of disturbances and uncertain parameters is discussed,based on a Hamiltonian *** the effect of time delay during control and transmission,a H...
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The adaptive H_∞ control problem of multi-machine power system in the case of disturbances and uncertain parameters is discussed,based on a Hamiltonian *** the effect of time delay during control and transmission,a Hamilton model with control time delay is ***-Krasovskii function is selected,and a controller which makes the system asymptotically stable is *** controller not only achieves the stability control for nonlinear systems with time delay,but also has the ability to suppress the external disturbances and adaptive ability to system parameter *** simulation results show the effect of the controller.
In this work,a novel two-time-scale control structure is proposed to perform the motion control problem of the underactuated mechanical *** allows us to analyze the system dynamics in each time scale ***,the underactu...
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ISBN:
(数字)9789887581536
ISBN:
(纸本)9781665482561
In this work,a novel two-time-scale control structure is proposed to perform the motion control problem of the underactuated mechanical *** allows us to analyze the system dynamics in each time scale ***,the underactuated mechanical system is divided into the actuated and the unactuated parts,since that the singular perturbations theorem could be applied ***,in order to facilitate the different speed of convergence,a small positive constant is designed in the auxiliary control variable of actuated *** the low gains can make sure that the actuated states can converge to the desired position in its domain ***,the PD controller with high gains in contrast could have a fast speed,meanwhile the reference trajectory is settled for the unactuated ***,the final controller constructed by incorporating the characteristics of system model has a low *** results on the underactuated system are given to verify the efficacy of the strategy.
Based on the design concept of virtual instrument and the design method of function modulation, using PC machine and data acquisition card as hardware system, proposed a design of sewage multi-parameter online monitor...
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In this paper,a compressive feedback scheme based on compressed sensing is investigated to reduce feedback load and enhance the sum throughput at low feedback rates for underwater acoustic MIMO ***,to avoid the outof-...
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ISBN:
(纸本)9781509009107
In this paper,a compressive feedback scheme based on compressed sensing is investigated to reduce feedback load and enhance the sum throughput at low feedback rates for underwater acoustic MIMO ***,to avoid the outof-date channel state information at the transmitter under the high dynamic underwater channel,we present a modified SL0(M-SLO) algorithm to recover the CSI at the transmitter,which adopts more steep approximate hyperbolic tangent function to approximate the l norm in the *** minimization problem of the l norm canbe transformed into a convex optimization problem for the smoothed ***,in order to solve the problem of slow convergence and inaccuracy estimation caused by notched ejfect of the gradient method,hybrid optimization algorithm that combines the advantages of the gradient method and the revised Newton method is introduced to improve the accuracy of sparse *** simulations show that the recovery accuracy and speed are improved by the proposed M-SL0 algorithm comparing with SL0,OMP ***,CSI feedback based compressive sensing performs better than the feedback based on a vector quantitation codebook.
The stability and the Hopf bifurcation of a nonlinear electromechanical coupling system with time delay feedback are studied. By considering the energy in the air-gap field of the AC motor, the dynamical equation of t...
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The stability and the Hopf bifurcation of a nonlinear electromechanical coupling system with time delay feedback are studied. By considering the energy in the air-gap field of the AC motor, the dynamical equation of the electromechanical coupling transmission system is deduced and a time delay feedback is introduced to control the dynamic behaviors of the system. The characteristic roots and the stable regions of time delay are determined by the direct method, and the relationship between the feedback gain and the length summation of stable regions is analyzed. Choosing the time delay as a bifurcation parameter, we find that the Hopf bifurcation occurs when the time delay passes through a critical value.A formula for determining the direction of the Hopf bifurcation and the stability of the bifurcating periodic solutions is given by using the normal form method and the center manifold theorem. Numerical simulations are also performed, which confirm the analytical results.
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