Apollo: Any easy way to make ADC change lane and pass slow speed car ahead?

[wobistdu]

Hi :

Currently the lane_borrow (or sidepass) decider is only valid for static obstacle.
If there is only one referenceline, the ADC will use that path and follow the slow car now.

Is there any way to make ADC change lane so it can pass the slow speed car ahead?

In previous version there is dp_poly_path/dp_poly_path_optimizer.cc which can be tuned to consider dynamic cost weight.
In latest master, insider the path_bounds_decider.cc,
// 4. Adjust the boundary considering dynamic obstacles
// TODO(all): may need to implement this in the future.

Any suggestion for this?
Thanks

[panjiacheng]

Hi,
Thanks for the question. The current path-decision can take care of slow-speed obstacles. Here are a few parameters that you can tune to achieve your goal:

• path_decider_obstacle_utils.cc line 40: Here you can modify it by deleting the "IsStatic()" check and increase the FLAGS_static_obstacle_speed_threhold to be the slow-speed threshold you want. The ADC will try to side-pass any obstacle below this given speed.

• path_lane_borrow_decider.cc line 103: The FLAGS_lane_borrow_max_speed is the speed for the ADC to start side-pass. If you want the ADC to be able to start side-pass at a faster speed, you can increase this value (at the cost of reduced safety so please be careful).

• path_lane_borrow_decider.cc line 110: Only when the ADC thinks the blocking obstacle is a long-term one, it will start side-pass. Here you can specify how many frames an obstacle is blocking can it be defined as a "long-term" blocking obstacle. For example, if you specify it to be 10, then only when the ADC sees a slow-car ahead for 10frames (1sec) will the ADC start to pass the slow-car.

• path_bounds_decider.cc line 270: Here you see that the boundary is determined by lane-width, if you want, you can replace it with the function GetBoundaryFromRoads, what that will do is to use the entire road (likely consisting multiple lanes) as the boundary, ADC will try to use any path that it can find on the road, without considering whether it needs to borrow neighbor lane or not, etc. Normally, we don't suggest use this because it might create some safety issues. But as you can see, at line 319, when the ADC needs to pull-over, especially in emergency situation, it will use this method to find a path.

Hope this answers your questions. Thanks.

[wobistdu]

Thanks

Hi,
Thanks for the question. The current path-decision can take care of slow-speed obstacles. Here are a few parameters that you can tune to achieve your goal:

• path_decider_obstacle_utils.cc line 40: Here you can modify it by deleting the "IsStatic()" check and increase the FLAGS_static_obstacle_speed_threhold to be the slow-speed threshold you want. The ADC will try to side-pass any obstacle below this given speed.
• path_lane_borrow_decider.cc line 103: The FLAGS_lane_borrow_max_speed is the speed for the ADC to start side-pass. If you want the ADC to be able to start side-pass at a faster speed, you can increase this value (at the cost of reduced safety so please be careful).
• path_lane_borrow_decider.cc line 110: Only when the ADC thinks the blocking obstacle is a long-term one, it will start side-pass. Here you can specify how many frames an obstacle is blocking can it be defined as a "long-term" blocking obstacle. For example, if you specify it to be 10, then only when the ADC sees a slow-car ahead for 10frames (1sec) will the ADC start to pass the slow-car.
• path_bounds_decider.cc line 270: Here you see that the boundary is determined by lane-width, if you want, you can replace it with the function GetBoundaryFromRoads, what that will do is to use the entire road (likely consisting multiple lanes) as the boundary, ADC will try to use any path that it can find on the road, without considering whether it needs to borrow neighbor lane or not, etc. Normally, we don't suggest use this because it might create some safety issues. But as you can see, at line 319, when the ADC needs to pull-over, especially in emergency situation, it will use this method to find a path.

Hope this answers your questions. Thanks.

Thanks for the suggestion, I already tried changing path_bound_decider to make the boundary to the whole road and let it consider all dynamic obstacles , it would overtake the obstacles without switching to lane_bollow scenario(stitch in the lane_follower )
I will try the lane_borrow later