In this paper, a study of control for an uncertain2-degree of freedom(DOF) helicopter system is given. The2-DOF helicopter is subject to input deadzone and output constraints. In order to cope with system uncertaintie...In this paper, a study of control for an uncertain2-degree of freedom(DOF) helicopter system is given. The2-DOF helicopter is subject to input deadzone and output constraints. In order to cope with system uncertainties and input deadzone, the neural network technique is introduced because of its capability in approximation. In order to update the weights of the neural network, an adaptive control method is utilized to improve the system adaptability. Furthermore, the integral barrier Lyapunov function(IBLF) is adopt in control design to guarantee the condition of output constraints and boundedness of the corresponding tracking errors. The Lyapunov direct method is applied in the control design to analyze system stability and convergence. Finally, numerical simulations are conducted to prove the feasibility and effectiveness of the proposed control based on the model of Quanser's 2-DOF helicopter.展开更多
This paper presents a novel mechanical attachment, i.e., nonlinear energy sink （NES）, for suppressing the limit cycle oscillation （LCO） of an airfoil. The dynamic responses of a two-degree-of-freedom （2-DOF） air...This paper presents a novel mechanical attachment, i.e., nonlinear energy sink （NES）, for suppressing the limit cycle oscillation （LCO） of an airfoil. The dynamic responses of a two-degree-of-freedom （2-DOF） airfoil coupled with an NES are studied with the harmonic balance method. Different structure parameters of the NES, i.e., mass ratio between the NES and airfoil, NES offset, NES damping, and nonlinear stiffness in the NES, are chosen for studying the effect of the LCO suppression on an aeroelastic system with a supercritical Hopf bifurcation or subcritical Hopf bifurcation, respectively. The results show that the structural parameters of the NES have different influence on the supercritical Hopf bifurcation system and the subcritical Hopf bifurcation system.展开更多
针对智能装备系统直线与旋转两自由度驱动需求,提出定子励磁型混合磁路直线旋转永磁(statorexcitedhybrid magnetic circuit linear and rotary permanent magnet,SEHMCLRPM)电机,采用轴向和径向双凸极齿结构,轴向直线运动与径向旋转运...针对智能装备系统直线与旋转两自由度驱动需求,提出定子励磁型混合磁路直线旋转永磁(statorexcitedhybrid magnetic circuit linear and rotary permanent magnet,SEHMCLRPM)电机,采用轴向和径向双凸极齿结构,轴向直线运动与径向旋转运动磁场共用定、转子磁路。永磁体设置在定子上,动子上既无绕组也无永磁体,动子结构简单坚固,重量轻,具有转矩惯量比高、动态响应速度快、可靠性高等特点;定子同时设置有直线与旋转两套绕组,直线和旋转运动控制独立,降低两自由度驱动控制的复杂度。分析该类电机的运行原理和结构特点,探讨混合磁路特征,构建该类SEHMC-LRPM电机的解耦等效磁路模型,实现该类电机的磁路设计。在此基础上,基于3D有限元方法分析混合磁路与两自由度耦合磁场,揭示两自由度磁场与电机磁场分布、空载和负载特性的关系。最后,加工制造样机,并进行实验研究,验证该电机结构的有效性和理论分析的正确性。展开更多
The S-type test is simulated based on a ship manoeuvring mathematical model of 4 degrees of freedom(4-DOF);simultaneously,sensitivity analysis of the hydrodynamic coefficients in the mathematical model is implemented ...The S-type test is simulated based on a ship manoeuvring mathematical model of 4 degrees of freedom(4-DOF);simultaneously,sensitivity analysis of the hydrodynamic coefficients in the mathematical model is implemented by using an indirect method.The mathematical model is simplified by omitting the coefficients of smaller sensitivity according to the results of sensitivity analysis.The 10°/10° zigzag test and 35° turning circle manoeuvre are simulated with the original and the simplified mathematical models.The comparison of the simulation results shows the effectiveness of the sensitivity analysis and the validity of the simplified model.展开更多
基金supported by the National Natural Science Foundation of China(61803085,61806052,U1713209)the Natural Science Foundation of Jiangsu Province of China(BK20180361)
文摘In this paper, a study of control for an uncertain2-degree of freedom(DOF) helicopter system is given. The2-DOF helicopter is subject to input deadzone and output constraints. In order to cope with system uncertainties and input deadzone, the neural network technique is introduced because of its capability in approximation. In order to update the weights of the neural network, an adaptive control method is utilized to improve the system adaptability. Furthermore, the integral barrier Lyapunov function(IBLF) is adopt in control design to guarantee the condition of output constraints and boundedness of the corresponding tracking errors. The Lyapunov direct method is applied in the control design to analyze system stability and convergence. Finally, numerical simulations are conducted to prove the feasibility and effectiveness of the proposed control based on the model of Quanser's 2-DOF helicopter.
基金Project supported by the National Natural Science Foundation of China(No.11172199)the KeyProgram of Tianjin Natural Science Foundation of China(No.11JCZDJC25400)
文摘This paper presents a novel mechanical attachment, i.e., nonlinear energy sink （NES）, for suppressing the limit cycle oscillation （LCO） of an airfoil. The dynamic responses of a two-degree-of-freedom （2-DOF） airfoil coupled with an NES are studied with the harmonic balance method. Different structure parameters of the NES, i.e., mass ratio between the NES and airfoil, NES offset, NES damping, and nonlinear stiffness in the NES, are chosen for studying the effect of the LCO suppression on an aeroelastic system with a supercritical Hopf bifurcation or subcritical Hopf bifurcation, respectively. The results show that the structural parameters of the NES have different influence on the supercritical Hopf bifurcation system and the subcritical Hopf bifurcation system.
文摘针对智能装备系统直线与旋转两自由度驱动需求,提出定子励磁型混合磁路直线旋转永磁(statorexcitedhybrid magnetic circuit linear and rotary permanent magnet,SEHMCLRPM)电机,采用轴向和径向双凸极齿结构,轴向直线运动与径向旋转运动磁场共用定、转子磁路。永磁体设置在定子上,动子上既无绕组也无永磁体,动子结构简单坚固,重量轻,具有转矩惯量比高、动态响应速度快、可靠性高等特点;定子同时设置有直线与旋转两套绕组,直线和旋转运动控制独立,降低两自由度驱动控制的复杂度。分析该类电机的运行原理和结构特点,探讨混合磁路特征,构建该类SEHMC-LRPM电机的解耦等效磁路模型,实现该类电机的磁路设计。在此基础上,基于3D有限元方法分析混合磁路与两自由度耦合磁场,揭示两自由度磁场与电机磁场分布、空载和负载特性的关系。最后,加工制造样机,并进行实验研究,验证该电机结构的有效性和理论分析的正确性。
基金the National Natural Science Foundation of China(No.51279106)the Special Research Fund for the Doctoral Program of Higher Education of China(No.20110073110009)
文摘The S-type test is simulated based on a ship manoeuvring mathematical model of 4 degrees of freedom(4-DOF);simultaneously,sensitivity analysis of the hydrodynamic coefficients in the mathematical model is implemented by using an indirect method.The mathematical model is simplified by omitting the coefficients of smaller sensitivity according to the results of sensitivity analysis.The 10°/10° zigzag test and 35° turning circle manoeuvre are simulated with the original and the simplified mathematical models.The comparison of the simulation results shows the effectiveness of the sensitivity analysis and the validity of the simplified model.
