The occurrence regularity of Phyllocnistis citreua in northern Guizhou was investigated,and the relationship between summer shoot controlling of citrus and occurrence of P. citreua was studied. The results showed that...The occurrence regularity of Phyllocnistis citreua in northern Guizhou was investigated,and the relationship between summer shoot controlling of citrus and occurrence of P. citreua was studied. The results showed that P. citreua occurred from May to September every year in northern Guizhou,and the occurrence reached the peak from early May to late June and from early July to late August. The occurrence in early and mid July was the most serious. The free-sprouting time had a close relationship with occurrence quantity and damage level of P. citreua. The earlier the free-sprouting time was,the greater the occurrence quantity and damage level of P. citreua was. The integrated control techniques focused on timely erasing summer shoots and controlling shoots were suggested to use in production,in order to control the occurrence of P. citreua.展开更多
The optimal control of multibody spacecraft during the stretching process of solar arrays is investigated,and a hybrid optimization strategy based on Gauss pseudospectral method（GPM） and direct shooting method（DSM...The optimal control of multibody spacecraft during the stretching process of solar arrays is investigated,and a hybrid optimization strategy based on Gauss pseudospectral method（GPM） and direct shooting method（DSM） is presented. First, the elastic deformation of flexible solar arrays was described approximately by the assumed mode method, and a dynamic model was established by the second Lagrangian equation. Then, the nonholonomic motion planning problem is transformed into a nonlinear programming problem by using GPM. By giving fewer LG points, initial values of the state variables and control variables were obtained. A serial optimization framework was adopted to obtain the approximate optimal solution from a feasible solution. Finally, the control variables were discretized at LG points, and the precise optimal control inputs were obtained by DSM. The optimal trajectory of the system can be obtained through numerical integration. Through numerical simulation, the stretching process of solar arrays is stable with no detours, and the control inputs match the various constraints of actual conditions.The results indicate that the method is effective with good robustness.展开更多
文摘The occurrence regularity of Phyllocnistis citreua in northern Guizhou was investigated,and the relationship between summer shoot controlling of citrus and occurrence of P. citreua was studied. The results showed that P. citreua occurred from May to September every year in northern Guizhou,and the occurrence reached the peak from early May to late June and from early July to late August. The occurrence in early and mid July was the most serious. The free-sprouting time had a close relationship with occurrence quantity and damage level of P. citreua. The earlier the free-sprouting time was,the greater the occurrence quantity and damage level of P. citreua was. The integrated control techniques focused on timely erasing summer shoots and controlling shoots were suggested to use in production,in order to control the occurrence of P. citreua.
基金supported by the National Natural Science Foundation of China (11472058)
文摘The optimal control of multibody spacecraft during the stretching process of solar arrays is investigated,and a hybrid optimization strategy based on Gauss pseudospectral method（GPM） and direct shooting method（DSM） is presented. First, the elastic deformation of flexible solar arrays was described approximately by the assumed mode method, and a dynamic model was established by the second Lagrangian equation. Then, the nonholonomic motion planning problem is transformed into a nonlinear programming problem by using GPM. By giving fewer LG points, initial values of the state variables and control variables were obtained. A serial optimization framework was adopted to obtain the approximate optimal solution from a feasible solution. Finally, the control variables were discretized at LG points, and the precise optimal control inputs were obtained by DSM. The optimal trajectory of the system can be obtained through numerical integration. Through numerical simulation, the stretching process of solar arrays is stable with no detours, and the control inputs match the various constraints of actual conditions.The results indicate that the method is effective with good robustness.
