In the fiber winding process,strong disturbance,uncertainty,strong coupling,and fiber friction complicate the winding constant tension control.In order to effectively reduce the influence of these problems on the tens...In the fiber winding process,strong disturbance,uncertainty,strong coupling,and fiber friction complicate the winding constant tension control.In order to effectively reduce the influence of these problems on the tension output,this paper proposed a tension fluctuation rejection strategy based on feedforward compensation.In addition to the bias harmonic curve of the unknown state,the tension fluctuation also contains the influence of bounded noise.A tension fluctuation observer(TFO)is designed to cancel the uncertain periodic signal,in which the frequency generator is used to estimate the critical parameter information.Then,the fluctuation signal is reconstructed by a third-order auxiliary filter.The estimated signal feedforward compensates for the actual tension fluctuation.Furthermore,a time-varying parameters fractional-order PID controller(TPFOPID)is realized to attenuate the bounded noise in the fluctuation.Finally,TPFOPID is enhanced by TFO and applied to control a tension control system considering multi-source disturbances.The stability of the method is analyzed by using the Lyapunov theorem.Finally,numerical simulations verify that the proposed scheme improves the tracking ability and robustness of the system in response to tension fluctuations.展开更多
波动范围(Scale of Fluctuation,SOF)是表征土体空间变异性的重要参数。为了探究土性参数波动范围的最优化算法及影响因素,该研究通过对比分析随机场法和地质统计学法的异同点,采用控制变量法对土性参数在不同条件下计算了SOF值,探讨了...波动范围(Scale of Fluctuation,SOF)是表征土体空间变异性的重要参数。为了探究土性参数波动范围的最优化算法及影响因素,该研究通过对比分析随机场法和地质统计学法的异同点,采用控制变量法对土性参数在不同条件下计算了SOF值,探讨了数据的趋势性、拟合参数初值、拟合点个数等因素对土性参数SOF计算结果的影响。研究结果表明:1)在利用随机场法和地质统计学法计算SOF时,去趋势化可以消除数据趋势性带来的影响,归一化可以减少不同初值对计算结果的影响。2)提出了一种同时适用于随机场法与地质统计学法的确定拟合参数初值及拟合点个数的统一方法,并在此基础上计算了某工程非饱和黏土土性参数的竖直SOF,其范围为0.14~0.62 m。研究成果可为农田的土壤改良及农田精细管理提供依据。展开更多
基金funded by the National Natural Science Foundation of China(Grant Number 52075361)Shanxi Province Science and Technology Major Project(Grant Number 20201102003)+3 种基金Lvliang Science and Technology Guidance Special Key R&D Project(Grant Number 2022XDHZ08)National Natural Science Foundation of China(Grant Number 51905367)Shanxi Natural Science Foundation General Project(Grant Numbers 202103021224271,202203021211201)Shanxi Province Key Research and Development Plan(Grant Number 202102020101013).
文摘In the fiber winding process,strong disturbance,uncertainty,strong coupling,and fiber friction complicate the winding constant tension control.In order to effectively reduce the influence of these problems on the tension output,this paper proposed a tension fluctuation rejection strategy based on feedforward compensation.In addition to the bias harmonic curve of the unknown state,the tension fluctuation also contains the influence of bounded noise.A tension fluctuation observer(TFO)is designed to cancel the uncertain periodic signal,in which the frequency generator is used to estimate the critical parameter information.Then,the fluctuation signal is reconstructed by a third-order auxiliary filter.The estimated signal feedforward compensates for the actual tension fluctuation.Furthermore,a time-varying parameters fractional-order PID controller(TPFOPID)is realized to attenuate the bounded noise in the fluctuation.Finally,TPFOPID is enhanced by TFO and applied to control a tension control system considering multi-source disturbances.The stability of the method is analyzed by using the Lyapunov theorem.Finally,numerical simulations verify that the proposed scheme improves the tracking ability and robustness of the system in response to tension fluctuations.
文摘波动范围(Scale of Fluctuation,SOF)是表征土体空间变异性的重要参数。为了探究土性参数波动范围的最优化算法及影响因素,该研究通过对比分析随机场法和地质统计学法的异同点,采用控制变量法对土性参数在不同条件下计算了SOF值,探讨了数据的趋势性、拟合参数初值、拟合点个数等因素对土性参数SOF计算结果的影响。研究结果表明:1)在利用随机场法和地质统计学法计算SOF时,去趋势化可以消除数据趋势性带来的影响,归一化可以减少不同初值对计算结果的影响。2)提出了一种同时适用于随机场法与地质统计学法的确定拟合参数初值及拟合点个数的统一方法,并在此基础上计算了某工程非饱和黏土土性参数的竖直SOF,其范围为0.14~0.62 m。研究成果可为农田的土壤改良及农田精细管理提供依据。