# Transition Analysis and Its Application to Global Path Determination for a Biped Climbing Robot
## 4 Fast Determination of Feasible Global Paths
### Principle and Flowchart
With regard to the

Figure 10: Results of global path determination in Scene II consisting of 25 members. (**a**) Route I; (**b**) Route II; (**c**) Route III. complicated truss scene shown in Figure 10, whose members are randomly generated, the proposed algorithms also determine three possible global routes. From the results, we can see that the robot needs to perform 5 to 6 periods of transition in order to reach the target member. Routes I and III have a superiority in terms of transition number and path length over Route II. However, the routes are not so different from each other. They mainly branch off at the lower right local region where several squared members are concentrated, providing more potential gripping orientations. As a comparison of time consumed, the determination process requires 207.6 ms for the simple case, as compared to 1274.6 ms for the complicated one. ## 6 Conclusions and Future Work

Biped climbing robots represent an ideal automation solution so that human workers do not need to perform high-rise truss-related routine tasks. To freely move in the truss environments, member-to-member transition is a basic and important ability for biped climbing robots. In this paper, we presented a complete approach to compute the feasibility and corresponding operational regions for transiting from one member to another with biped climbing robots, such as Climbot. The transition analysis takes the safety, reachability, and accessibility of grips in to account. This achievement was then applied to the rapid determination of global paths as a core evaluation for the first time. Simulations successfully verified the effectiveness and efficiency of the presented analysis and algorithms. A novel contribution of this paper is the presentation of a systematic scheme to quantitatively analyze the feasibility of member-to-member transition performed with biped climbing robots. This scheme solves the operational region completely. However, the proposed transition analysis has its own limitation. Owing to the introduction of planar configuration constraints (not usually the case for robots with more than 5 DoF), the transition analysis is only applicable to robots with up to 5 DoF. Another contribution of this paper is a novel path planning algorithm to rapidly determinate feasible global routes for biped climbing robots to move in 3D complex truss environments. This path planning algorithm is greatly beneficial to all the biped climbing robots if their transition capabilities can be modeled and calculated, by outputting global guidance for subsequent planning procedures. In the near future, we will explore a more general idea for performing transition analysis, which will be applicable to all biped climbing robots. We also plan to propose criteria for the evaluation of the global routes' qualities, and then develop subsequent planners to generate the entire climbing path, i.e., optimal grip sequencer and single-step motion planner. Extensive climbing experiments on various trusses will be conducted to further verify our planning algorithms. This research is supported in part by the National Natural Science Foundation of China (Grant Nos. 51605096, 51705086), the NSFC-Guangdong Joint Fund (Grant No. U1401240), the Frontier and Key Technology Innovation Special Funds of Guangdong Province (Grant Nos. 2014B090919002, 2015B010917003, 2015B009922003, 2017B050506008), and the Program of Foshan Innovation Team of Science and Technology (Grant No. 2015 IT100072). [PERSON] and [PERSON] co-organized the work. [PERSON] and [PERSON] conceived and designed the planner and performed the simulation work. [PERSON] wrote the manuscript. [PERSON] analyzed the simulation data, and co-worked with [PERSON] to prepare the final manuscript. [PERSON] and [PERSON] co-supervised the research. The authors declare no conflict of interest. ## References

* (1) [PERSON]; [PERSON]; [PERSON]; [PERSON] Mobility and Manipulation of a Light-weight Space Robot. _Robot. Auton. Syst._**1994**, _13_, 1-12.