To solve the receding horizon control （RHC） problem in an online manner, a novel numerical method called the indirect Radau pseudospectral method （IRPM） is proposed in this paper. Based on calculus of variations a...To solve the receding horizon control （RHC） problem in an online manner, a novel numerical method called the indirect Radau pseudospectral method （IRPM） is proposed in this paper. Based on calculus of variations and the first-order necessary optimality condition, the RHC problem for linear time-varying （LTV） system is transformed into the two-point boundary value problem （TPBVP）. The Radau pseudospectral approximation is employed to discretize the TPBVP into well-posed linear algebraic equations. The resulting linear algebraic equations are solved via a matrix partitioning approach afterwards to obtain the optimal feedback control law. For the nonlinear system, the linearization method or the quasi linearization method is employed to approximate the RHC problem with successive linear approximations. Subsequently, each linear problem is solved via the similar method which is used to solve the RHC problem for LTV system. Simulation results of three examples show that the IRPM is of high accuracy and of high compu- tation efficiency to solve the RHC problem and the stability of closed-loop systems is guaranteed.展开更多
A new method of parameter identification based on linear time-frequencyrepresentation and Hubert transform is proposed to identity modal parameters of linear time-varyingsystems from measured vibration responses. Usin...A new method of parameter identification based on linear time-frequencyrepresentation and Hubert transform is proposed to identity modal parameters of linear time-varyingsystems from measured vibration responses. Using Gabor expansion and synthesis theory, measuredresponses are represented in the time-frequency domain and modal components are reconstructed bytime-frequency filtering. The Hilbert transform is applied to obtain time histories of the amplitudeand phase angle of each modal component, from which time-varying frequencies and damping ratios areidentified. The proposed method has been demonstrated with a numerical example in which a lineartime-varying system of two degrees of freedom is used to validate the identification scheme based ontime-frequency representation. Simulation results have indicated that time-frequency representationpresents an effective tool for modal parameter identification of time-varying systems.展开更多
研究具有线性时变扰动的多变量控制系统性能评价的方法.通过将时变扰动分为三类定常扰动,进而构造一个加权的性能指标,权值矩阵与不同扰动类型和优先级相对应.在指定合理的输出方差后,运用对角关联矩阵方法明确计算出广义多变量系统闭...研究具有线性时变扰动的多变量控制系统性能评价的方法.通过将时变扰动分为三类定常扰动,进而构造一个加权的性能指标,权值矩阵与不同扰动类型和优先级相对应.在指定合理的输出方差后,运用对角关联矩阵方法明确计算出广义多变量系统闭环输出方差的上下限值.经过ITAE(Integral of time-weighted absolute value of the error)寻优得到最小输出方差下的控制器参数,并给出可实现的最优控制器模型.仿真实例证明了该方法计算的简便性和有效性.展开更多
基金supported by the National Natural Science Foundation of China(Nos.61174221 and 61402039)
文摘To solve the receding horizon control （RHC） problem in an online manner, a novel numerical method called the indirect Radau pseudospectral method （IRPM） is proposed in this paper. Based on calculus of variations and the first-order necessary optimality condition, the RHC problem for linear time-varying （LTV） system is transformed into the two-point boundary value problem （TPBVP）. The Radau pseudospectral approximation is employed to discretize the TPBVP into well-posed linear algebraic equations. The resulting linear algebraic equations are solved via a matrix partitioning approach afterwards to obtain the optimal feedback control law. For the nonlinear system, the linearization method or the quasi linearization method is employed to approximate the RHC problem with successive linear approximations. Subsequently, each linear problem is solved via the similar method which is used to solve the RHC problem for LTV system. Simulation results of three examples show that the IRPM is of high accuracy and of high compu- tation efficiency to solve the RHC problem and the stability of closed-loop systems is guaranteed.
基金Automobile Industrial Science Foundation of Shanghai (No.2000187)
文摘A new method of parameter identification based on linear time-frequencyrepresentation and Hubert transform is proposed to identity modal parameters of linear time-varyingsystems from measured vibration responses. Using Gabor expansion and synthesis theory, measuredresponses are represented in the time-frequency domain and modal components are reconstructed bytime-frequency filtering. The Hilbert transform is applied to obtain time histories of the amplitudeand phase angle of each modal component, from which time-varying frequencies and damping ratios areidentified. The proposed method has been demonstrated with a numerical example in which a lineartime-varying system of two degrees of freedom is used to validate the identification scheme based ontime-frequency representation. Simulation results have indicated that time-frequency representationpresents an effective tool for modal parameter identification of time-varying systems.
文摘研究具有线性时变扰动的多变量控制系统性能评价的方法.通过将时变扰动分为三类定常扰动,进而构造一个加权的性能指标,权值矩阵与不同扰动类型和优先级相对应.在指定合理的输出方差后,运用对角关联矩阵方法明确计算出广义多变量系统闭环输出方差的上下限值.经过ITAE(Integral of time-weighted absolute value of the error)寻优得到最小输出方差下的控制器参数,并给出可实现的最优控制器模型.仿真实例证明了该方法计算的简便性和有效性.
文摘针对一类具有可确定"时滞"的线性时变多变量控制系统的性能评价方法进行研究。利用特别定义的关联矩阵和正常相乘的方法,计算出LTV MIMO过程广义最小方差控制律的解析解,并由此获得了广义最小方差基准。为避免估计关联矩阵所带来的困难,利用过程数据和关联矩阵阶数建立了LTV MIMO GMV基准上界。理论和仿真研究表明,上述方法能够正确和有效地评价LTV MIMO系统。
