Path planning failed —— Node 1 can not reachable from Node 2

[Ji-Zhou]

No description provided.

[Ji-Zhou]

Dear colleagues

I have configured a custom map in Roadrunner. The roads in the custom map are connected by junctions, which have been configured.

And some spawn points were set along the road in UE4 Carla.

—Problem1: But when I plan my path in UE4 Carla, I often face failures—"Node 1 can not reachable from Node 2". It is interesting that sometimes node 1 can reach node 2 but node 2 cannot reach node 1.

Specially, when i run the code—(route = grp.trace_route(origin, destination)). I will get successed result from SpawnPoint26 to 10, but failed from SpawnPoint 10 to 26.


—Problem2: Another problem is that when I call traffic_generation.py, some autonomous vehicles seem unable to travel along the road and will cross the terrain between the two roads. As shown:


—Problem3: I have set the starting and ending points that cannot be planned in problem 1 in the automatic_control.py. It seems to have found a route, but still faces the problem 2: intending to cross some infeasible terrain.

Many thanks

[leomilk-eng]

@Ji-Zhou I know the reason for this problem. The reason why the planning cannot be done is that your road is not closed. The default planning is the A* algorithm, which causes an exception to be thrown when the road cannot be found. If you need a solution, please contact me.

[Ji-Zhou]

@leomilk-eng Thanks for your reply. I also discovered this reason. In fact, the road i need is not closed, and i need to do is to achieve path planning in such a scenario.
When the starting and ending points are on lanes in different directions, the algorithm will fail because the road is not closed , and the default A * algorithm only searches along the specified direction of the road. I want to change this. Do you have any good ideas? I want to allow vehicles to cross roads in different directions while path planning!