位移约束下智能桁架的强度最优控制

Optimum strength control of adaptive trusses subject to nodal displacement constraints

针对智能桁架结构,提出了在考虑多点位移约束的情况下,使结构工作应力处于最佳状态的规划法最优控制模型。当结构位移约束起主要作用时,模型可在保证位移约束的前提下,同时尽可能提高结构的承载能力;当结构位移并不重要时,仍可用该模型来提高结构的承载能力。对于复杂结构,为了提高控制效果,可以调整为了满足位移条件而需要的作动器数目及布置方案。文中给出了数值算例,说明该方法的调控能力。

For adaptive truss structures, a control model that makes the working status of structures to be optimum and subject to multiple nodal displacement component constraints is presented. By using the adjustable ability of actuators embedded in the members of the structures, the strength and precision of static indeterminate trusses with coupling character of internal force are improved. Explicit expressions of member internal forces and nodal displacements to active deformations of actuators are deduced. The model is solved by mathematical programming method. When the nodal displacement component constraint is active, this model can improve the loading capacity of structures and ensure the nodal displacement component constraints. Moreover, when the nodal displacement component constraint is inactive, this model can still be used to improve the loading capacity of static indeterminate truss structures. For static indeterminate truss, the displacement constraint may induce increasing the maximum stress in structural controlling. For static determinate truss, the displacement constraint has no effect on the maximum stress in the structure. For complicated structures, in order to improve the efficiency of control, the number and displacement method of actuators can be changed. The control efficiency of this model is illustrated by numerical examples. It shows that few actuators can implement strength control and meet displacement constraints simultaneously.