Nonlinear suboptimal tracking control of spacecraft approaching a tumbling target<xref rid="cpb_27_9_090501_fn1" ref-type="fn">*</xref><fn id="cpb_27_9_090501_fn1"><label>*</label><p>Project supported by the Major Program of the National Natural Science Foundation of China (Grant Nos. 61690210 and 61690213).</p></fn>

Nonlinear suboptimal tracking control of spacecraft approaching a tumbling target**

Project supported by the Major Program of the National Natural Science Foundation of China (Grant Nos. 61690210 and 61690213).

Xu Zhan-Peng¹, Chen Xiao-Qian^{1, †}, Huang Yi-Yong¹, Bai Yu-Zhu¹, Yao Wen²

(color online) Norms of position tracking errors.