## 5 Conclusions  
This paper conducts an overall design of the mechanical structure of lunar exploration robots based on the characteristics of low temperature, low gravity, strong adhesion of lunar soil and strong corrosiveness on the Moon. It uses 3D modeling software to build a three-dimensional model of the lunar exploration hexapod robot and designs an \"inverted gait\" motion mode based on the tripod gait. In this mode, at the beginning, three legs swing backward, causing the robot to present an inverted posture. This provides a larger swinging space for the robot's legs. The greater swing of the hip joint improves the effective step length of the robot in a straight motion. It also reduces the pauses during the transition between the swinging and supporting legs, thereby increasing the robot's forward speed. It enhances the stability of robot motion by reducing joint torque. Subsequently, experiments and comparisons of the two gaits were conducted in simulation software. Data analysis revealed that, in the inverted gait mode, the robot's displacement distance increased by about 29% in the same time period. It also reduced left and right deviations as well as vertical oscillations during straight-line motion. The angular velocity of the hip joint increased by about 25%, and the maximum peak value of the angular acceleration of the first set of knee joints decreased by about 19.7%, while the second set decreased by about 3.9%. The transition between the swinging of the two leg sets became smoother, enhancing the stability of the robot's motion. Additionally, the increased swing amplitude of the joints during motion resulted in larger centrifugal forces on the corresponding joint parts, affecting the moment of inertia. The variation in joint swing amplitude also increased the coupling effect between robot joints, reducing the maximum torque borne by the robot's joints and improving the robot's load capacity. Finally, experimental tests were conducted on a prototype to verify the rationality of the robot's structural design. The test results showed that the lunar exploration hexapod robot has a reasonable structure and smooth motion and can achieve the predesigned motion requirements. However, there are still some issues in the simulation and experimental processes: This paper only conducted simulation studies of the robot's walking in tripod and inverted gaits under the condition of a sine wave input. Subsequent research should include other input motion laws and the study of quadruped and adaptive gaits. The simulation experiments were carried out with an equivalent simplified model due to the complexity of the actual lunar exploration hexapod robot's model structure. However, the environment of the Moon is exceptionally unique, with complex and variable conditions, especially a relatively large number of craters and rough terrain. Further analysis is needed to study the kinematics and dynamics of the lunar exploration hexapod robot crawling in craters, aiming to optimize the overall mechanical structure. The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app14010260/sl](https://www.mdpi.com/article/10.3390/app14010260/sl)]([https://www.mdpi.com/article/10.3390/app14010260/sl](https://www.mdpi.com/article/10.3390/app14010260/sl)). Conceptualization, Y-Q.G. and W-H.L. ; methodology, Y-Q.G. ; software, W-H.L. and B.-M.S. ; validation, Y-Q.G., Z.-D.X. and W-H.L. ; formal analysis, Y-Q.G., W-H.L. and B.-M.S. ; investigation, Z.-D.X. and D.-K.Y. ; resources, Y-Q.G. and Z-D.X. ; data curation, Y-Q.G., W-H.L. and D.-K.Y. ; writing--original draft preparation, Y-Q.G. and W-H.L. ; writing--review and editing, Y-Q.G. and W-H.L. ; visualization, Y-Q.G. and W-H.L. ; supervision, Y-Q.G. ; project administration, Y.-Q.G. ; funding acquisition, Z.-D.X. All authors have read and agreed to the published version of the manuscript. This research was funded by the National Natural Science Foundation of China (NSFC) Integrated Project, grant number U2037602. Not applicable.