Stability condition of the proportional control algorithm is given for a fixed target. 针对固定目标，文中给出了比例控制算法的稳定性条件。
The stability of the helical equilibrium is analyzed with phase plane method, and an analytical criterion of stability is revealed. 用相平面法分析螺旋线平衡的稳定性，导出解析形式的稳定性条件。
An ordinary star such as the sun is a splendidly controlled machine that can go on operating under stable conditions for an immense length of time. 象太阳那样的一颗普通恒星就是一架十分巧妙的可控机器，它能在稳定条件下持续运转异常长的时间。
Due to the idea of parameter-dependent Lyapunov stability, the obtained robust stability condition has less conservativeness than the one based on quadratic stability. 因为使用了参数依赖的李亚普诺夫稳定性思想，此鲁棒稳定条件比基于二次稳定概念的稳定条件的保守性更小。
