The stability of the motion control system is one of the decisive factors of the control quality for Autonomous Underwater Vehicle（AUV）.The divergence of control,which the unstable system may be brought about,is fat...The stability of the motion control system is one of the decisive factors of the control quality for Autonomous Underwater Vehicle（AUV）.The divergence of control,which the unstable system may be brought about,is fatal to the operation of AUV.The stability analysis of the PD and S-surface speed controllers based on the Lyapunov＇s direct method is proposed in this paper.After decoupling the six degree-of-freedom（DOF）motions of the AUV,the axial dynamic behavior is discussed and the condition is deduced,in which the parameters selection within stability domain can guarantee the system asymptotically stable.The experimental results in a tank and on the sea have successfully verified the algorithm reliability,which can be served as a good reference for analyzing other AUV nonlinear control systems.展开更多
The pump is one of the most important energy consuming devices in an energy system. The axial force on a centrifugal pump is an important factor for improving the operation stability and the service life. Based on the...The pump is one of the most important energy consuming devices in an energy system. The axial force on a centrifugal pump is an important factor for improving the operation stability and the service life. Based on the Bernoulli’s equation, the formulas of the axial clearance are derived theoretically. The relationship between the impeller axial force, the clearance leakage flow rate and the axial clearance is obtained. The motion differential equation of the axial-auto-balanced impeller is established by the number axis modeling method. The asymptotic stability of the impeller is evaluated by the Lyapunov stability analysis. The transient simulation of the axial-auto-balanced impeller is carried out by the method of the computational fluid dynamics (CFD) with the dynamic mesh technology. The time required for the impeller to reach the stable state under different conditions is calculated. The effective values of the axial force are determined. This research is useful to improve the operation stability of the pump.展开更多
基金supported by the National High Technology Development Program of China(863Program,Grant No.2008AA092301)the Fundamental Research Foundation of Harbin Engineering University(Grant No.HEUFT08001)the Postdoctoral Science Foundation of China(Grant No.20080440838)
文摘The stability of the motion control system is one of the decisive factors of the control quality for Autonomous Underwater Vehicle（AUV）.The divergence of control,which the unstable system may be brought about,is fatal to the operation of AUV.The stability analysis of the PD and S-surface speed controllers based on the Lyapunov＇s direct method is proposed in this paper.After decoupling the six degree-of-freedom（DOF）motions of the AUV,the axial dynamic behavior is discussed and the condition is deduced,in which the parameters selection within stability domain can guarantee the system asymptotically stable.The experimental results in a tank and on the sea have successfully verified the algorithm reliability,which can be served as a good reference for analyzing other AUV nonlinear control systems.
基金the National Natural Science Foundation ofChina(Grant Nos.51909131,52079142 and 51836010)。
文摘The pump is one of the most important energy consuming devices in an energy system. The axial force on a centrifugal pump is an important factor for improving the operation stability and the service life. Based on the Bernoulli’s equation, the formulas of the axial clearance are derived theoretically. The relationship between the impeller axial force, the clearance leakage flow rate and the axial clearance is obtained. The motion differential equation of the axial-auto-balanced impeller is established by the number axis modeling method. The asymptotic stability of the impeller is evaluated by the Lyapunov stability analysis. The transient simulation of the axial-auto-balanced impeller is carried out by the method of the computational fluid dynamics (CFD) with the dynamic mesh technology. The time required for the impeller to reach the stable state under different conditions is calculated. The effective values of the axial force are determined. This research is useful to improve the operation stability of the pump.
