following error的用法和样例：
例句
- By theoretical analysis, it is shown that tracking error converges to a small neighborhood of zero.
通过李亚普诺夫方法，证明了跟踪误差收敛到零的一个小邻域内。 - It was proved that the tracking error converges to the prescribed boundary layer and all the signals in the closed-loop system were bounded.
算法保证闭环系统所有信号的有界性且使得跟踪误差收敛于任意设定的饱和层内。
