# Failure-Robot Path Complementation for Robot Swarm Mission Planning
## 5 Path Programming and Experiment Results
### Tests and Results  
This research included several simulations and a full function test. The maximum distance limit by battery capacity was set at 360 m only to fit the largest available size of the pavement field (150 x 150 m) for the experiment, and the shortest total distance paths and the total distance limits for each robot car were set so that they could not exceed these limitations (set as: ITL = 30, ISC = 50, IRTL = 30, CRTL = 30 IRSC = 50, CRSC = 50, and TSC = 2). After all these settings were completed, the paths were dispatched to the robot cars to make them run on their assigned optimum paths.  
Figure 18; Figure 19 illustrate ideal paths generated by the algorithm to demonstrate the efficacy considering the \"no-travel zone avoidance\" function before real field experiments. The test began by randomly setting 30 target points that vehicles must visit and setting a no-travel zone marked as a red rectangle. It was assumed that the battery could only provide a maximum distance limit of 360 m for each car. As shown in Figure 18, the system automatically programed and then dispatched three routes using the 2 TS+2 OP algorithm without considering the no-travel zone. Consequently, the A path was 194.1 m, the B path was 236.2 m, the C path was 203.9 m, the shortest total distance path was 634.2 m, and the CPU time was 2.77 s.  
Although none of the paths exceeded the maximum distance limit, the no-travel zone was touched by the B path. This issue can be solved by the improved no-travel zone algorithm of the next test. In Figure 18, the turning points generated for this case are indicated by the light-blue dots. As the test result, the A path was 194.1 m, the B path was 248.3 m, the C path was 203.9 m, the total distance path was 646.3 m, and the CPU time was 2.54 s. None of the paths exceeded the battery's maximum distance limit (360 m), and all paths successfully bypassed the no-travel zone.  
The next test was an actual full function field test (included path programming, no-travel zone avoidance, and failure complementation) run with scratch-build robot cars. In the beginning of this test, the monitoring station automatically dispatched three optimal paths to the robot cars to visit all target points; however, during the mission, Car-A's battery was intentionally disconnected (at the point shown in Figure 20) to simulate a failure of a car, and the algorithm could reprogram the path so that the companion healthy cars could complete the remaining path successfully. The trajectory (before failure) of each robot car is shown in Figure 19. According to the log, Car-A failed during the mission at 127.1 m. Because the remote monitoring station did not receive the response from Car-A due to its power cut, the monitoring station automatically sent a command to stop all cars and began re-programming. At this point, Car-B had run 187.2 m, while Car-C was arriving at the 144.8 m mark, and failed Car-A had stopped with four targets unvisited. In this case, the unfinished A path was randomly inserted into another path, and path re-programming was immediately conducted to complement the failure. Figure 21 shows that the remaining path of Car-A was rapidly complemented by Car-B. The re-programming CPU time was 0.24 s, the B Path was 83.9 m, and the C Path was 145.4 m. The remaining paths were re-allocated to Car -B and Car-C to complete the task. The actual distance that Car-B ran after the failure was 90.9 m, while Car-C ran 150.2 m. In total, 241.1 m were run after the failure. The actual trajectory of each robot car in this experiment is shown in Figure 22.  
Figure 19: The shortest route programmed by the algorithm considering the no-travel zone.  
Figure 20: Trajectories at the moment Car-A failed (the red circle).  
For the final step, the individual distances run by each car (Car A: 127.1 m, Car B: 271.1 m, and Car C: 290.2 m) were obtained, and it was found that none exceeded the maximum distance limit (360 m). The total distance run by the three cars was 688.4 m.