A new algorithm namely the interval sampling method, applicable to the analysisof steady-state simulation output is proposed. This algorithm uses the time series analysisto carry out conrrelation analysis of the stead...A new algorithm namely the interval sampling method, applicable to the analysisof steady-state simulation output is proposed. This algorithm uses the time series analysisto carry out conrrelation analysis of the steady-state simulation output so as to obtain theobservation data which are actually uncorrelated in nature. On the basis of theseuncorrelated data gathered, some satisfactory deductions cam be made on the data under re search. A comparison between batch means method and the interval sampling method hasbeen performed by taking the M/M/l queuing system as an example. The results attestedthat the interval sampling method is mere accurate than the batch means method.展开更多
In this paper, the process of dynamic heat output in a welding pool and the variation of the penetration caused by the section change of the workpiece are analyzed using numerical simulation technique of thermal fie...In this paper, the process of dynamic heat output in a welding pool and the variation of the penetration caused by the section change of the workpiece are analyzed using numerical simulation technique of thermal field. It is concluded that the variation of temperature gradient in HAZ along the length and width direction reflects the heat output of the welding pool, and that the output of the welding pool has a homogenous relationship to the pool penetration.展开更多
Objective:To assess the hydrodynamic function of a newly China-made Jiuling bileaflet heart valve prosthesis at different simulated cardiac output.Methods:Jiuling valve,CarboMedics valve and C-L tilting disc valve hav...Objective:To assess the hydrodynamic function of a newly China-made Jiuling bileaflet heart valve prosthesis at different simulated cardiac output.Methods:Jiuling valve,CarboMedics valve and C-L tilting disc valve have been tested in the aortic position of the pulsatile flow simulator.The testing condition is set at the simulated cardiac output of 2.0,3.0,4.0,and 5.0 L/min and a constant pulsatile frequency of 75 beats/min.The mean pressure difference(ΔP),leakage volume(LEV)and closing volume(CLV)across each valve,and the effective orifice area(EOA)have been analyzed.Results:The mean ΔP of all the Jiuling valves is in the range of below 10 mmHg and decreases with increasing the tissue annulus diameter.The ΔP of 25 mm CarboMedics is about 1.5 times of the same sized Jiuling valve and 27mm C-L tilting disc valve is about 71.8% higher than the same sized Jiuling valve.The EOA of the Jiuling mechanical valves increases with increasing the given cardiac output or the tissue annulus diameter,but 25 mm CarboMedics and 27 mm C-L tilting disc valve is similar to 21 mm and 23 mm Jiuling heart valve.The CLV of the Jiuling prosthetic cardiac valve is in the range of below 11%(normalized by stroke volume),25 mm Jiuling valve is about 56.4% lower than 25 mm CarboMedics and 27 mm Jiuling valve is about 11.4% higher than 27 mm C-L tilting disc valve.The LEV of the Jiuling prosthetic cardiac valves is in the range of below 28.9% (normalized by stroke volume),25 mm Jiuling prosthetic valve is about lower 27.3% than 25 mm CarboMedics and 27 mm Jiuling valve is about lower 11.2% than 27 mm C-L tilting disc valve.Conclusion:For a given tissue diameter,the newly Jiuling heart valve prostheses show more satisfactory hemodynamic characteristics at different cardiac output.展开更多
A simulation tool named BITSIM orienting production engineering is developed in order to improve enterprise＇s productivity and making up the scarcity of computer application. The architecture of BITSIM is presented f...A simulation tool named BITSIM orienting production engineering is developed in order to improve enterprise＇s productivity and making up the scarcity of computer application. The architecture of BITSIM is presented first. Hierarchical technique, control strategy based on multi-agent and simulation output analysis are depicted in detail then. In the end, an application example is taken out to prove that this system could be used to analyzing different hypothetical situation and configuring the auxiliary manufacturing system before production.展开更多
为减小重载升沉补偿绞车的体积和转动惯量,提出一种壳动双排柱塞多作用内曲线径向柱塞马达。首先,基于无脉动副角分配方法对马达导轨曲线进行设计;随后,利用Simcenter 3D Motion与AMESim软件构建双马达机械-液压联合仿真模型。仿真结果...为减小重载升沉补偿绞车的体积和转动惯量,提出一种壳动双排柱塞多作用内曲线径向柱塞马达。首先,基于无脉动副角分配方法对马达导轨曲线进行设计;随后,利用Simcenter 3D Motion与AMESim软件构建双马达机械-液压联合仿真模型。仿真结果与理论分析基本吻合,表明马达输出特性符合预期设计目标,同时有效减小了绞车体积和转动惯量。最后,进一步针对相邻马达轴向错位安装角度及柱塞泄漏间隙对输出性能的影响开展仿真分析。相关结论可为升沉补偿绞车的工程设计与优化提供参考。展开更多
High dynamic tracking performance is a key technical index of hydraulic flight motion simulator(HFMS).However,the strong nonlinearities,various model uncertainties and measurement noise in hydraulic actuation systems ...High dynamic tracking performance is a key technical index of hydraulic flight motion simulator(HFMS).However,the strong nonlinearities,various model uncertainties and measurement noise in hydraulic actuation systems limit the high dynamic performance improvement.In this paper,the outer axis frame of a HFMS is taken as a case study and its nonlinear dynamic model with consideration of strong nonlinearities,matched and mismatched uncertainties is established.A novel cascaded extended state observer(ESO)is proposed to estimate the unavailable system states to avoid the adverse effect of measurement noise on control performance.Meanwhile,the designed cascaded ESO also produces estimates of matched and mismatched uncertainties.Then,an output feedback robust controller(OFRC)is proposed by integrating the cascaded ESO with a robust integral of the sign of the error(RISE)feedback based on the backstepping framework.The proposed controller achieves compensation of both matched and mismatched model uncertainties in an output feedback form.Theoretical analysis indicates that the proposed OFRC ensures the boundedness of all closed-loop system signals in the presence of matched and mismatched timevarying model uncertainties.Excellent asymptotic tracking performance can also be obtained when the model uncertainties are time-invariant.Comparative experimental results show that the proposed OFRC achieves significant performance improvement compared with the extensively employed PI control with velocity feedforward(VFPI).展开更多
文摘A new algorithm namely the interval sampling method, applicable to the analysisof steady-state simulation output is proposed. This algorithm uses the time series analysisto carry out conrrelation analysis of the steady-state simulation output so as to obtain theobservation data which are actually uncorrelated in nature. On the basis of theseuncorrelated data gathered, some satisfactory deductions cam be made on the data under re search. A comparison between batch means method and the interval sampling method hasbeen performed by taking the M/M/l queuing system as an example. The results attestedthat the interval sampling method is mere accurate than the batch means method.
文摘In this paper, the process of dynamic heat output in a welding pool and the variation of the penetration caused by the section change of the workpiece are analyzed using numerical simulation technique of thermal field. It is concluded that the variation of temperature gradient in HAZ along the length and width direction reflects the heat output of the welding pool, and that the output of the welding pool has a homogenous relationship to the pool penetration.
文摘Objective:To assess the hydrodynamic function of a newly China-made Jiuling bileaflet heart valve prosthesis at different simulated cardiac output.Methods:Jiuling valve,CarboMedics valve and C-L tilting disc valve have been tested in the aortic position of the pulsatile flow simulator.The testing condition is set at the simulated cardiac output of 2.0,3.0,4.0,and 5.0 L/min and a constant pulsatile frequency of 75 beats/min.The mean pressure difference(ΔP),leakage volume(LEV)and closing volume(CLV)across each valve,and the effective orifice area(EOA)have been analyzed.Results:The mean ΔP of all the Jiuling valves is in the range of below 10 mmHg and decreases with increasing the tissue annulus diameter.The ΔP of 25 mm CarboMedics is about 1.5 times of the same sized Jiuling valve and 27mm C-L tilting disc valve is about 71.8% higher than the same sized Jiuling valve.The EOA of the Jiuling mechanical valves increases with increasing the given cardiac output or the tissue annulus diameter,but 25 mm CarboMedics and 27 mm C-L tilting disc valve is similar to 21 mm and 23 mm Jiuling heart valve.The CLV of the Jiuling prosthetic cardiac valve is in the range of below 11%(normalized by stroke volume),25 mm Jiuling valve is about 56.4% lower than 25 mm CarboMedics and 27 mm Jiuling valve is about 11.4% higher than 27 mm C-L tilting disc valve.The LEV of the Jiuling prosthetic cardiac valves is in the range of below 28.9% (normalized by stroke volume),25 mm Jiuling prosthetic valve is about lower 27.3% than 25 mm CarboMedics and 27 mm Jiuling valve is about lower 11.2% than 27 mm C-L tilting disc valve.Conclusion:For a given tissue diameter,the newly Jiuling heart valve prostheses show more satisfactory hemodynamic characteristics at different cardiac output.
文摘A simulation tool named BITSIM orienting production engineering is developed in order to improve enterprise＇s productivity and making up the scarcity of computer application. The architecture of BITSIM is presented first. Hierarchical technique, control strategy based on multi-agent and simulation output analysis are depicted in detail then. In the end, an application example is taken out to prove that this system could be used to analyzing different hypothetical situation and configuring the auxiliary manufacturing system before production.
文摘为减小重载升沉补偿绞车的体积和转动惯量,提出一种壳动双排柱塞多作用内曲线径向柱塞马达。首先,基于无脉动副角分配方法对马达导轨曲线进行设计;随后,利用Simcenter 3D Motion与AMESim软件构建双马达机械-液压联合仿真模型。仿真结果与理论分析基本吻合,表明马达输出特性符合预期设计目标,同时有效减小了绞车体积和转动惯量。最后,进一步针对相邻马达轴向错位安装角度及柱塞泄漏间隙对输出性能的影响开展仿真分析。相关结论可为升沉补偿绞车的工程设计与优化提供参考。
基金supported in part by the National Natural Science Foundation of China under Grant 51905271,Grant 52075262in part by the Natural Science Foundation of Jiangsu Province under Grant BK20190459+1 种基金in part by the Fundamental Research Funds for the Central Universities under Grant 30920041101in part by the Open Foundation of the State Key Laboratory of Fluid Power and Mechatronic Systems under Grant GZKF-201910。
文摘High dynamic tracking performance is a key technical index of hydraulic flight motion simulator(HFMS).However,the strong nonlinearities,various model uncertainties and measurement noise in hydraulic actuation systems limit the high dynamic performance improvement.In this paper,the outer axis frame of a HFMS is taken as a case study and its nonlinear dynamic model with consideration of strong nonlinearities,matched and mismatched uncertainties is established.A novel cascaded extended state observer(ESO)is proposed to estimate the unavailable system states to avoid the adverse effect of measurement noise on control performance.Meanwhile,the designed cascaded ESO also produces estimates of matched and mismatched uncertainties.Then,an output feedback robust controller(OFRC)is proposed by integrating the cascaded ESO with a robust integral of the sign of the error(RISE)feedback based on the backstepping framework.The proposed controller achieves compensation of both matched and mismatched model uncertainties in an output feedback form.Theoretical analysis indicates that the proposed OFRC ensures the boundedness of all closed-loop system signals in the presence of matched and mismatched timevarying model uncertainties.Excellent asymptotic tracking performance can also be obtained when the model uncertainties are time-invariant.Comparative experimental results show that the proposed OFRC achieves significant performance improvement compared with the extensively employed PI control with velocity feedforward(VFPI).
