基于线性矩阵不等式 (LMI)方法 ,考虑了连续和离散对象的降阶正实控制器设计问题 .通过一阶对象的分析表明 ,广义对象阶是最小阶正实控制器阶的可达上界 ,因此降阶正实控制器的存在性依赖于具体对象参数 .给出了一个新的降阶正实控制器阶的上界 ,该上界蕴涵了已有结果 .上界的估计是构造性的 ,可以给出这种降阶正实控制器的设计算法 .文中给出了简单的算例 ,说明本文方法的可行性 Based on the linear matrix inequality (LMI) method, the decentralized real controller design for continuous and discrete objects is considered. The analysis of first-order objects shows that the generalized object order is the reachable upper bound of the minimum order real controller, Therefore, the existence of a reduced-order real controller depends on the parameters of a particular object. A new upper bound for a reduced-order real controller is given. The upper bound implies the existing results. The upper bound is constructive , We can give the design algorithm of this reduced-order real controller.In this paper, a simple example is given to illustrate the feasibility of this method