Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Issue with Plugin and Sensor Size Constraint #2270

Open
2 tasks done
HoangGiang93 opened this issue Dec 4, 2024 · 0 comments
Open
2 tasks done

Issue with Plugin and Sensor Size Constraint #2270

HoangGiang93 opened this issue Dec 4, 2024 · 0 comments
Labels
bug Something isn't working

Comments

@HoangGiang93
Copy link

HoangGiang93 commented Dec 4, 2024 •
edited
Loading

Intro

Hi!

I am a researcher at Institute for Artificial Intelligence, University of Bremen, I use MuJoCo for my research.

My setup

MuJoCo: 3.2.7
API: C
OS: Ubuntu 20.04 / 24.04

What's happening? What did you expect?

I'm trying to implement a custom plugin for my use case, using the sensor plugin as a starting point. While working with touch_grid.xml, I noticed something unexpected:

In the XML, there is only one sensor attached to the site named "touch". However, during debugging, I observed the following behavior with the lambda function plugin.nsensordata:

  1. It's called twice.
  2. In the first call, the values are always:
    • m->sensor_objid[sensor_id] = 0
    • m->sensor_objtype[sensor_id] = mjOBJ_UNKNOWN
  3. In the second call, the values are correct:
    • m->sensor_objid[sensor_id] and m->sensor_objtype[sensor_id] have the expected values.

Upon further investigation, I found that:

  • The first call determines sensor_size and the second call determines m->nsensordata to satisfy the constraint mentioned in engine_io.c.

This behavior creates a challenge for my use case because:

  • My sensor size depends on m->sensor_objid[sensor_id] and m->sensor_objtype[sensor_id].
  • This causes the constraint to be violated.

Questions:

  1. How can I address this issue and ensure my sensor size is calculated correctly without violating the constraint?
  2. I also noticed that the constructor for the sensor is called twice. Is this redundant, or is it expected behavior?

Any insights or suggestions would be greatly appreciated. Thank you!

Steps for reproduction

  1. Open file touch_grid.cc.
  2. Add from line 506 the following codes:
const int obj_id = m->sensor_objid[sensor_id];
const char *obj_name = mj_id2name(m, mjtObj::mjOBJ_SITE, obj_id);
const int obj_type = m->sensor_objtype[sensor_id];
printf("Object id: %d\n", obj_id);
printf("Object name: %s\n", obj_name);
if (obj_type == mjOBJ_SITE)
{
  printf("Object is of type mjOBJ_SITE\n");
}
else if (obj_type == mjOBJ_UNKNOWN)
{
  printf("Object is of type mjOBJ_UNKNOWN\n");
}
else
{
  printf("Object is of type %d\n", obj_type);
}

  1. Build it and simulate touch_grid.xml or the below XML (with a dummy site).

  2. The output would be:

Object id: 0
Object name: dummy
Object is of type mjOBJ_UNKNOWN
Object id: 1
Object name: touch
Object is of type mjOBJ_SITE

Minimal model for reproduction

<mujoco model="touchtest">
  <compiler autolimits="true"/>
  <extension>
    <plugin plugin="mujoco.sensor.touch_grid"/>
  </extension>
  <asset>
    <texture name="grid" type="2d" builtin="checker" rgb1=".1 .2 .3" rgb2=".2 .3 .4" width="300" height="300" mark="edge" markrgb=".2 .3 .4"/>
    <material name="grid" texture="grid" texrepeat="3 1" texuniform="true"/>
    <hfield file="a.png" size="0.2 0.2 0.02 0.015"/>
  </asset>
  <visual>
      <headlight ambient=".7 .7 .7" diffuse=".2 .2 .2" specular="0.1 0.1 0.1"/>
      <map znear="0.01"/>
      <scale contactwidth=".02" contactheight=".5"/>
  </visual>
  <default>
    <geom friction="0.4" solimp="0 0.95 0.02"/>
  </default>
  <statistic center="0 0 1" extent="1" meansize=".1"/>
  <worldbody>
    <light pos="1 0 .3" dir="-1 0 -.3"/>
    <light pos="-1 0 .3" dir="1 0 -.3"/>
    <geom name="floor" pos="0 0 -0.01" type="plane" size="1 1 .01"/>
    <geom name="a" type="hfield" hfield="a" rgba=".5 .5 .7 1"/>
    <body name="ball" pos="0 0 1">
      <joint name="x" type="slide" axis="1 0 0" damping="1"/>
      <joint name="y" type="slide" axis="0 1 0" damping="1"/>
      <joint name="z" type="slide" axis="0 0 1"/>
      <joint name="rx" axis="1 0 0" springdamper="0.2 1"/>
      <joint name="ry" axis="0 1 0" springdamper="0.2 1"/>
      <geom type="ellipsoid" size=".3 .5 .1" mass="0.1" rgba=".5 .5 .5 .3"/>
      <site name="dummy"/>
      <site name="touch" pos="0 0 .1"/>
    </body>
  </worldbody>
  <sensor>
    <plugin name="touch" plugin="mujoco.sensor.touch_grid" objtype="site" objname="touch">
      <config key="size" value="7 7"/>
      <config key="fov" value="45 45"/>
      <config key="gamma" value="0"/>
      <config key="nchannel" value="3"/>
    </plugin>
  </sensor>
</mujoco>

Code required for reproduction

No response

Confirmations
@HoangGiang93 HoangGiang93 added the bug Something isn't working label Dec 4, 2024
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Assignees
No one assigned
Labels
bug Something isn't working
Projects
None yet
Milestone
No milestone
Development

No branches or pull requests
1 participant
@HoangGiang93