Variable geometry truss manipulator （VGTM） has potential to work in the future space applications, of which a dynamic model is important to dynamic analysis and control of the system. In this paper, an approach is p...Variable geometry truss manipulator （VGTM） has potential to work in the future space applications, of which a dynamic model is important to dynamic analysis and control of the system. In this paper, an approach is presented to model the dynamic equations of a VGTM by independent variables, which consists of two double-octahedral truss units and a 3-revolute-prismatic-spherical （3-RPS） parallel manipulator. In this ap- proach, the kinematic recursive relations of two adjacent bodies and geometric constrains are used to deduce the kinematic equations of the VGTM, and Jourdain＇s velocity varia- tion principle is adopted to establish the dynamic equations of the system. The validity of the proposed dynamic model is verified by comparison of numerical simulations with the software ADAMS. Besides, an active controller for trajectory tracking of the system is designed by the computed torque method. The effectiveness of the controller is numer- ically proved.展开更多
To compute the matching performance of diesel engine with variable geometry turboeharger（VGT）, the formerly used program is improved through adjustment of turbine mass flow rate and efficiency characteristics. The c...To compute the matching performance of diesel engine with variable geometry turboeharger（VGT）, the formerly used program is improved through adjustment of turbine mass flow rate and efficiency characteristics. The calculation result is applied to forecast the performance of J6110Z diesel engine with rotary-vaned VGT70, and to guide the improvement of engine fuel supply. The computed engine performance curve coincides with the experiment result well： the low-speed torque, fuel economy, exhaust temperature and boost pressure of the VGT engine are all improved.展开更多
针对采用PID方法控制废气再循环(exhaust gas recirculation,EGR)和可变截面涡轮增压器(variable geometry turbocharge,VGT)阀开度时出现的进气质量流量和增压压力瞬态响应慢的现象提出了一种新的EGR与VGT解耦控制策略,并进行了试验验...针对采用PID方法控制废气再循环(exhaust gas recirculation,EGR)和可变截面涡轮增压器(variable geometry turbocharge,VGT)阀开度时出现的进气质量流量和增压压力瞬态响应慢的现象提出了一种新的EGR与VGT解耦控制策略,并进行了试验验证。研究结果表明:由工况点900r/min、200N·m变化至工况点1200r/min、1100N·m的过程中,采用解耦控制策略后,增压压力和进气质量流量的上升时间分别由8.5s和21.3s降至7.9s和16.8s,降幅分别为7.1%和21.1%;稳定时间分别由14.3s和18.3s降至11.5s和15.1s,降幅分别为19.6%和17.5%;WHTC测试循环下,解耦工况点占总工况点的比例达到36.1%,PM比排放和油耗的降低幅度分别为18.9%和5.8%,NOx比排放变化不明显。展开更多
A turbocharged diesel engine model was built with the GT-Power software,and experimentally verified.Then two different control variables for the control of the variable geometry turbocharger（VGT）were described,and t...A turbocharged diesel engine model was built with the GT-Power software,and experimentally verified.Then two different control variables for the control of the variable geometry turbocharger（VGT）were described,and their distinct effects on engine performance,i.e.NOxand soot emissions and fuel consumption,were simulated and compared on the basis of this model.The results showed that NOxemissions decreased obviously with the increase of exhaust gas recirculation（EGR）rate at constant boost pressure condition,but soot emissions and fuel consumption considerably increased.It was a good way to reduce NOxemissions without increasing fuel consumption and soot emissions when VGT was controlled to maintain the excess oxygen ratio unchanged as EGR rate increases.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.11132001,11272202,and 11472171)the Key Scientific Project of Shanghai Municipal Education Commission(No.14ZZ021)the Natural Science Foundation of Shanghai(No.14ZR1421000)
文摘Variable geometry truss manipulator （VGTM） has potential to work in the future space applications, of which a dynamic model is important to dynamic analysis and control of the system. In this paper, an approach is presented to model the dynamic equations of a VGTM by independent variables, which consists of two double-octahedral truss units and a 3-revolute-prismatic-spherical （3-RPS） parallel manipulator. In this ap- proach, the kinematic recursive relations of two adjacent bodies and geometric constrains are used to deduce the kinematic equations of the VGTM, and Jourdain＇s velocity varia- tion principle is adopted to establish the dynamic equations of the system. The validity of the proposed dynamic model is verified by comparison of numerical simulations with the software ADAMS. Besides, an active controller for trajectory tracking of the system is designed by the computed torque method. The effectiveness of the controller is numer- ically proved.
基金the Ministerial Level Advanced Research Foundation (37256)
文摘To compute the matching performance of diesel engine with variable geometry turboeharger（VGT）, the formerly used program is improved through adjustment of turbine mass flow rate and efficiency characteristics. The calculation result is applied to forecast the performance of J6110Z diesel engine with rotary-vaned VGT70, and to guide the improvement of engine fuel supply. The computed engine performance curve coincides with the experiment result well： the low-speed torque, fuel economy, exhaust temperature and boost pressure of the VGT engine are all improved.
文摘针对采用PID方法控制废气再循环(exhaust gas recirculation,EGR)和可变截面涡轮增压器(variable geometry turbocharge,VGT)阀开度时出现的进气质量流量和增压压力瞬态响应慢的现象提出了一种新的EGR与VGT解耦控制策略,并进行了试验验证。研究结果表明:由工况点900r/min、200N·m变化至工况点1200r/min、1100N·m的过程中,采用解耦控制策略后,增压压力和进气质量流量的上升时间分别由8.5s和21.3s降至7.9s和16.8s,降幅分别为7.1%和21.1%;稳定时间分别由14.3s和18.3s降至11.5s和15.1s,降幅分别为19.6%和17.5%;WHTC测试循环下,解耦工况点占总工况点的比例达到36.1%,PM比排放和油耗的降低幅度分别为18.9%和5.8%,NOx比排放变化不明显。
基金Supported by Diesel Engine Development Program of MIIT(DEDP-1004)Natural Science Foundation of BIT(3030012211428)
文摘A turbocharged diesel engine model was built with the GT-Power software,and experimentally verified.Then two different control variables for the control of the variable geometry turbocharger（VGT）were described,and their distinct effects on engine performance,i.e.NOxand soot emissions and fuel consumption,were simulated and compared on the basis of this model.The results showed that NOxemissions decreased obviously with the increase of exhaust gas recirculation（EGR）rate at constant boost pressure condition,but soot emissions and fuel consumption considerably increased.It was a good way to reduce NOxemissions without increasing fuel consumption and soot emissions when VGT was controlled to maintain the excess oxygen ratio unchanged as EGR rate increases.
