**5. Conclusions and Future Work**

A 5-DOF pruning manipulator was designed, and the relative position and attitude of each coordinate system were obtained by establishing the theoretical model of manipulator kinematics. The workspace of the manipulator was obtained through the simulation analysis of the workspace of the manipulator (−600~800 mm in the X direction, −800~800 mm in the Y direction, and −200~1800 mm in the Z direction). It was verified that the geometric size of the manipulator met the requirements of the pruning space of jujube trees in the dwarf and densely planted jujube garden. Finally, a prototype manipulator was developed, and the positioning accuracy test of the end-effector and pruning performance test of the manipulator were carried out, based on high-speed camera technology. The results show that the positioning errors of the manipulator at different pruning points were all less than 10 mm, the average pruning success rate of the manipulator was about 89.10%, and the average pruning time of a single jujube tree was 27.7 min. It was verified that the structure and control system of the pruning manipulator was reasonable and feasible. This study can provide a theoretical basis and technical support for the intelligent pruning of a jujube garden.

This paper mainly studied the mechanical structure and control system of the manipulator, but there are still pruning failures in the pruning tests of jujube trees. The aim of the subsequent study is to optimize the structure of the manipulator body and improve the control system to further improve the success rate of manipulator pruning. At the same time, the machine vision system will be equipped on the manipulator to realize the intelligent recognition and positioning of pruning points. Additionally, the mobile chassis and manipulator were integrated to carry out the experiment research of jujube-tree pruning in a natural environment, so as to realize the intelligent pruning of a jujube garden.

**Author Contributions:** Conceptualization, B.Z. and X.C.; Data curation, B.Z. and H.Z.; Formal analysis, B.Z. and C.S.; Funding acquisition, W.F. and C.S.; Investigation, B.Z., H.Z. and C.S.; Methodology, B.Z. and X.C.; Project administration, W.F. and C.S.; Resources, W.F. and C.S.; Software, B.Z. and H.Z.; Supervision, W.F.; Validation, B.Z., W.F., X.C., H.Z. and C.S.; Visualization, B.Z. and C.S.; Writing—original draft, B.Z. and H.Z.; Writing—review and editing, B.Z. and W.F. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was supported by the National Natural Science Foundation of China (NSFC), No. 51765058, Regional Innovation Guidance Project of the Xinjiang Production and Construction Group (No.2021BB020), Scientific and Technological Innovation Talents Program of the Xinjiang Production and Construction Group (No.2020CB008).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data presented in this study are available on-demand from the first author at (994026@hainanu.edu.cn).

**Acknowledgments:** The authors would like to thank their schools and colleges, as well as the funding of the project. All support and assistance are sincerely appreciated. Additionally, we sincerely appreciate the work of the editor and the reviewers of the present paper.

**Conflicts of Interest:** The authors declare no conflict of interest.
