The quadruped robot exhibits unstable motion when traversing obstacles.

[nanbwrn]

hi，everyone

When the code runs normally, the robot can stably traverse smaller obstacles. However, when continuously crossing several higher obstacles, the robot becomes unstable and falls. I am not sure if it is due to the lower calculation frequency or if there is an issue with the foot placement selection. Has anyone encountered this issue? could you give some advice?

Thank you, everyone.

Below is a simulation process video.

[hrxsd]

@nanbwrn I had the same problem as you, have you solved it yet?

[hrxsd]

I'm guessing it should be due to the camera view changing too quickly due to the body shaking of the robot in motion, which causes the height information in the elevation map to be skewed and the robot's footing point to be incorrectly predicted. You can find the robot's feet "plunging" into the map in the rviz interface, which is the same as what I'm experiencing (below).

https://github.com/qiayuanl/legged_perceptive/assets/126565504/680a5a65-bb0b-4120-b27f-7edeff6414d1

But I don't know how to solve this problem.

[tony-hj]

Hi, everyone.
What sensor are you using D435，T265 or both ? I got similar results to you when I used D435 alone, but I saw a video by liaoqiayuan used two sensors. I think it is the effect of using D435 and T265 together, but when I want When adding the T265 sensor, there was an error that the controller could not be loaded. Could you give me some advice? Thank you very much.

[ERROR] [1709299206.611116230, 18.830000000]: Exception thrown while initializing controller 'controllers/perceptive_controller'.
Mesh package://realsense2_description/meshes/t265.stl could not be found.
[ERROR] [1709299206.616946789, 18.832000000]: Initializing controller 'controllers/perceptive_controller' failed

by the way: I have put the t265.stl file into the corresponding folder, but this errror stoll exists.

[nanbwrn]

hi,@tony-hj
I've only used the D435 camera. Does anyone else have any suggestions? Thank you all.

[hrxsd]

Hi, @tony-hj
I also encountered the same error as you, then I just used d435 and encountered the same problem as @nanbwrn , and I haven't found a solution yet.

[tony-hj]

Hi @nanbwrn
This is a test video released by the author qiayuanl last year. I guess that the two sensors need to work synchronously for sensing and positioning. If only one D435 is used, the data obtained is insufficient, which may lead to unstable motion.
(https://www.youtube.com/watch?v=zcTuBe6d1qQ&ab_channel=QiayuanLiao)
This is why I'm trying to see if I can get T265 to work together, hoping to make progress

[tony-hj]

Hi, @hrxsd
This is a test video released by the author qiayuanl last year.
https://www.youtube.com/watch?v=zcTuBe6d1qQ&ab_channel=QiayuanLiao
I guess that if the robot dog can process like in the video, two sensors (D435 and T265) need to work together. We are currently only using D435, and the sensory data obtained is insufficient, so there will be a problem of unsmooth movement. . We can try to join T265 and see the results. Please let me know if there is any progress.

[hrxsd]

@tony-hj I think I solved the problem. First I found the t265.stl file on github and put it in the correct location, but it still reported that the file could not be found. Then I changed the contents of lines 41 and 49 in sensor_t265.xacro to change the file path to an absolute path and the problem was solved. This worked on my computer, looking forward to other solutions.

[nanbwrn]

hi， @hrxsd
I followed your instructions and modified the file paths accordingly. The simulation performance has indeed improved, and the robot can move more stably. In Gazebo, the T265 appears on the back of the robot, but the t265 model is not displayed in RViz.

Do you know how to set this up?

[hrxsd]

@nanbwrn I'm experiencing the same thing as yours and don't know why yet.

[hrxsd]

@nanbwrn Try adding file:// in front of the file path, I could see t265 in rviz after I added it.

[nanbwrn]

hi,@hrxsd
Thank you very much for your reply, and I apologize for responding so late.
Yes, making the changes as you suggested indeed allowed me to see the T265 in RViz.

[licongfei001]

Hi, @nanbwrn
Do you solved the problem? The convex region doesn't move with the robot. I think it's because of my wrong realsense gazebo plugin installation. Would I ask some help for you?