pr2 arm-object collision check

[iKrishneel]

I want the pr2 arm not to collide with the table during manipulation and I tried to use pqp-collision-check method.

The problem is if the links of the arm is inside the cube (representing the table), collision check does not report collision as shown in the attached picture. However if the arm is on the edge of the cube, collision is reported.

Code for this is here:

How to work about this issue?

[k-okada]

nice catch, this is very complex problem which caused from conversion between urdf model and eus model. urdf model consists of several links with rotational joint and fixed joint whereas eus model originally assume a link is consists of one link, not a multiple link connected by fixed joint as urdf do.

see https://gist.github.com/k-okada/2d0e4eacd2f0f5278fa7 for templary workaround (and also i modifed for better visualization, please compare this with yours carefully)

For better solution, we'll continue discussion at ->
jsk-ros-pkg/jsk_model_tools#171

[chiwunau]

I have a similar problem, where I am trying to solve IK while avoiding the robot's arm and base collide with the door model. The screenshot shows the result when I put every pair of door links and links from (send *pr2* :link-list (send *pr2* :rarm :end-coords :parent)) to :collision-avoidance-link-pair of IK. (code)
It seems that when searching in null-space, It only consider collision of bodies in the link-list. In this case many parts of arm and base are missing. Any workaround for this problem? especially for the base...

P.S. temporarily I replaced (setq b_gkmodel0_base_footprint_geom0 (instance pr2_gkmodel0_base_link_geom0 :init)) in pr2.l

[k-okada]

@chiwunau @iKrishneel
can we try "workaround" for this issue?

1. create list contains "body object" for each links, manually
2. create convex hull of these objects
3. replace collision object for each links
4. write this procedure within pr2-utils.l
   @furushchev can you help them?

[chiwunau]

Thank you, I will get @furushchev help and try writing the code.

[chiwunau]

screenshot_from_2016-06-14 17 52 40
screenshot_from_2016-06-14 17 53 05

This change (#232) can avoid the problem, I tested for IK and pqp-collision-check.
here is the test code