Space exploration has become a major focus in the field of technology,with gear transmissions in aerospace equipment playing a crucial role.In the extreme environment of space,gear transmissions face challenges like l...Space exploration has become a major focus in the field of technology,with gear transmissions in aerospace equipment playing a crucial role.In the extreme environment of space,gear transmissions face challenges like large temperature differentials,deformation and maintenance difficulties,which will severely impact transmission accuracy and service life.To meet the growing demands for high-performance gear transmissions with high transmission efficiency and error adaptability in the aerospace field,this paper proposes a novel curve-surface conjugate internal gear drive consisting of an involute internal gear and a curve-surface gear.The fundamental theory of curve-surface conjugation is introduced,and the construction method for curve-surface gear based on a selected contact path and meshing tube is presented.The analysis models including induced curvature,sliding ratio and tooth contact analysis with errors(ETCA)are simulated to evaluate the meshing characteristics.Additionally,prototypes are manufactured and experimental setups are established to validate the transmission performance.These results indicate that as the rotational speed increases,the transmission efficiency of the curve-surface conjugate internal gear drive improves,which is contrary to the trend observed in involute gear drives.And the transmission efficiency of the curve-surface conjugate internal gear drive surpasses that of the involute gear drive at higher rotational speeds.Moreover,this novel gear drive exhibits excellent error adaptability,maintaining intact contact paths and high transmission efficiency even in the presence of assembly errors.This study provides new ideas for the design and manufacture of high-performance gear transmissions from the perspective of spatial geometric elements.展开更多
This paper proposes a design of internal model control systems for process with delay by using support vector regression(SVR).The proposed system fully uses the excellent nonlinear estimation performance of SVR with t...This paper proposes a design of internal model control systems for process with delay by using support vector regression(SVR).The proposed system fully uses the excellent nonlinear estimation performance of SVR with the structural risk minimization principle.Closed-system stability and steady error are analyzed for the existence of modeling errors.The simulations show that the proposed control systems have the better control performance than that by neural networks in the cases of the training samples with small size and noises.展开更多
An IMC-PID controller was proposed for unstable second-order time delay system which shows the characteristics of inverse response(RHP zero). A plot of Ms versus λ was suggested to calculate the suitable tuning param...An IMC-PID controller was proposed for unstable second-order time delay system which shows the characteristics of inverse response(RHP zero). A plot of Ms versus λ was suggested to calculate the suitable tuning parameter λ, which provides a trade-off between performance and robustness. Six different forms of process models were selected from literature to show the applicability of the present method. Performance of controller was calculated by ITAE and total variation TV and compared with recently published tuning rules. Undesirable overshoot was removed by using a set-point weighting parameter. Robustness was tested by introducing a perturbation into the various model parameters and closed-loop results show that the designed controller is robust in the case of model uncertainty. The proposed method shows an overall better closed-loop response as compared to other recently reported methods.展开更多
基金Supported by Major Projects in Aviation Engines and Gas Turbines(Grant No.J2019-IV-0001-0068).
文摘Space exploration has become a major focus in the field of technology,with gear transmissions in aerospace equipment playing a crucial role.In the extreme environment of space,gear transmissions face challenges like large temperature differentials,deformation and maintenance difficulties,which will severely impact transmission accuracy and service life.To meet the growing demands for high-performance gear transmissions with high transmission efficiency and error adaptability in the aerospace field,this paper proposes a novel curve-surface conjugate internal gear drive consisting of an involute internal gear and a curve-surface gear.The fundamental theory of curve-surface conjugation is introduced,and the construction method for curve-surface gear based on a selected contact path and meshing tube is presented.The analysis models including induced curvature,sliding ratio and tooth contact analysis with errors(ETCA)are simulated to evaluate the meshing characteristics.Additionally,prototypes are manufactured and experimental setups are established to validate the transmission performance.These results indicate that as the rotational speed increases,the transmission efficiency of the curve-surface conjugate internal gear drive improves,which is contrary to the trend observed in involute gear drives.And the transmission efficiency of the curve-surface conjugate internal gear drive surpasses that of the involute gear drive at higher rotational speeds.Moreover,this novel gear drive exhibits excellent error adaptability,maintaining intact contact paths and high transmission efficiency even in the presence of assembly errors.This study provides new ideas for the design and manufacture of high-performance gear transmissions from the perspective of spatial geometric elements.
文摘This paper proposes a design of internal model control systems for process with delay by using support vector regression(SVR).The proposed system fully uses the excellent nonlinear estimation performance of SVR with the structural risk minimization principle.Closed-system stability and steady error are analyzed for the existence of modeling errors.The simulations show that the proposed control systems have the better control performance than that by neural networks in the cases of the training samples with small size and noises.
基金India (MHRD, India) for providing financial support
文摘An IMC-PID controller was proposed for unstable second-order time delay system which shows the characteristics of inverse response(RHP zero). A plot of Ms versus λ was suggested to calculate the suitable tuning parameter λ, which provides a trade-off between performance and robustness. Six different forms of process models were selected from literature to show the applicability of the present method. Performance of controller was calculated by ITAE and total variation TV and compared with recently published tuning rules. Undesirable overshoot was removed by using a set-point weighting parameter. Robustness was tested by introducing a perturbation into the various model parameters and closed-loop results show that the designed controller is robust in the case of model uncertainty. The proposed method shows an overall better closed-loop response as compared to other recently reported methods.
