following error的用法和樣例：
例句
- By theoretical analysis, it is shown that tracking error converges to a small neighborhood of zero.
通過李亞普諾夫方法，證明了跟蹤誤差收斂到零的一個小鄰域內。 - It was proved that the tracking error converges to the prescribed boundary layer and all the signals in the closed-loop system were bounded.
演算法保證閉環系統所有信號的有界性且使得跟蹤誤差收斂於任意設定的飽和層內。
