# Research on the Obstacle-Avoidance Steering Control Strategy of Tracked Inspection Robots
## 6 Conclusions  
In this paper, the theory of obstacle-avoidance steering control strategies can be applied to tracked robots in general, and precise trajectory-tracking control of tracked robots can be realized under the influence of skids and slips.  
(1) The steering radius of the tracked robot was analyzed according to its structural characteristics, the load analysis of the unit track length of the robot was completed and the expressions of the tractive force and steering resistance of the robot were established. Through the analysis and simulation of the steering plane dynamics of the robot, the corresponding relationships among the track structure, the relative steering radius and ground parameters were obtained under several typical road conditions.  
(2) The relationship between the driving parameters of the motor and the relative steering radius of the robot under skid and slip conditions were constructed. The corresponding relationship between the relative steering radius of the robot and the rotation speed and direction of the tracks on both sides of the robot were obtained by simulation analysis. The slip rate of the tracked robot is small when robot drive in a straight line. The tracked robot has a larger slip rate when turning in situ center, and the slip rate of the low-speed track (0.39) is greater than that of the high-speed track (0.35). The slip rate of the tracked robot using arc steering is small, and its slip rate is 0.27.  
(3) The steering control strategies of once turning in situ center, twice turning in situ center and large-radius steering were formulated to complete the obstacle-avoidance steering experiment. The trajectory of the robot using large-radius obstacle-avoidance steering motion was smooth, the steering speed was fast, and the efficiency was the highest. However, under large-radius steering, the skid and slip of the track had a great influence on the steering, the theoretical steering radius of the robot was R = 395 mm, and the actual steering radius was R = 634 mm. Therefore, more precise information is needed through scheme 3, such as the driving speed of the robot and road parameters. Using simulation analysis, the robot prototype completed the obstacle-avoidance steering experiment, which verifies the rationality of the robot skid-steering theory.  
This paper proposed that obstacle-avoidance steering control strategies can be applied to tracked devices in general, where the occurrence of skid and slip cannot be disregarded. This paper could provide a reference for autonomous obstacle-avoidance navigation control of tracked robots. But there are still some areas for improvement in this paper; in order to realize the steering control of robot obstacle-avoidance, it is necessary to build a control system including multi-sensor information fusion to detect road parameters in real time.  
**Author Contributions:** Conceptualization, C.W., H.M. and L.Z.; methodology, X.X. and H.T.; writing--original draft preparation, S.W. and H.Z.; writing--review and editing, C.W.; project administration, C.W. and L.Z. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This work was supported in part by the National Natural Science Foundation of China under Grant 51975468, in part by the Shaanxi Provincial Department of Education to Serve Local Special Program Projects under Grant 22 JC051, in part by the Key Laboratory of Road Construction Technology and Equipment under Grant 300102259508.  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The data presented in this study are available on request from the first author.  
**Conflicts of Interest:** The authors declare no conflict of interest.