Navam's profile - activity

hi,

i get this problem a lot ( yah my graphic drivers are kind of unstable) so what i do is -

1. rosrun rviz rviz --sync ( add the --sync it even says in the error message)
2. dont give up even with sync it will fail .... try it 2-3 times
3. if it still fails do rosmake rviz rviz and repeat step 1 :P

if it works for you , your welcome and if it doesnt well hopefully someone else here has another way :D

Navam

Hi,

i have a few doubts regarding the collision map -

1. is it possible to use our own cloud data as a collision map?
2. is there a possibility to identify clusters/cloud within the collision map as objects so that my arm does not consider those as collisions and can go near it..

i know these features should be present i am still looking for them, till then if any1 of you has any idea do let me know.

Thank you :)

Hi,

guys i was using normal trajectory motion(not the constraint aware one ) for picking up "Duplos" (yah the lego one's) till now and my prof has asked me to use collision free motion planning im having 0 success working with table top manipulation and i have managed to use move_arm package successfully- however the only problem i face is that when i try to pick the object it considers that as an obstacle and never goes near it.

Sooo what i have is - table cloud (segmented out) , the duplos segmented out individually. i saw the move_arm makes a collision map now if there was a way to remove my duplo cloud from the collision map my life should be good :D . Is there such a way and if there isnt guide me a little ill try and make it up and please dont tell me to use table top manipulation cause im seriously going nowhere with it :)

thanks :D

hey,

after launching pr2 in gazebo i add the available table in gazebo_worlds using roslaunch gazebo_worlds table.launch

soo i tried placing the table in a lot of places but the problem is that in all the examples of table top manipulation (both python and cpp exmaples) it never detects the table and gives error 2 = NO_TABLE ..

if any1 had a similar problem let me know i think there is some specification regarding the table that i just cant find O_O (possibly over looked).

Thanks :D

Ok so long story short i am trying to pick a block (imagine a small rectangular block 3x4x5 cms) so for that i have the X,Y,Z and its yaw (deviation/rotation along z axis) - soo what i basically am trying to do it go to the XY location (more specifically take the r_wrist_roll_link above the actual point ) and then try to grab the object as the arm goes down.

So after beating my head over trying to get the wrist/gripper to be perpendicularly down, messing with a lot of Quaternion values i found a value set {x,y,z,w} = {-n,0,n,0}, n can be any value the wrist is always perpendicularly down .... soon i realized life isnt this easy and with the above set i cant rotate the wrist at all, it can grab objects with only 1 orientation.

So i moved ahead trying to rotate wrist with roll pitch and yaw values (cause they make much more sense and can be visualized) and converted them to quaternions using the following code -

qw = (cos(R/2)cos(P/2)cos(Y/2))+(sin(R/2)sin(P/2)sin(Y/2));

qx = (sin(R/2)cos(P/2)cos(Y/2))-(cos(R/2)sin(P/2)sin(Y/2));

qy = (cos(R/2)sin(P/2)cos(Y/2))+(sin(R/2)cos(P/2)sin(Y/2));

qz = (cos(R/2)cos(P/2)sin(Y/2))-(sin(R/2)sin(P/2)cos(Y/2));

R= Roll , P=Pitch , Y=yaw and qw,qx,qy,qz are the quternions

well now the only problem i face is that the converted values(using the code above) makes expected motion, but isnt accurate enough.

Finally i wanted to ask the following things - 1. Is the above conversion correct (i did try some variations but this seems to be the one making most sense visually)? 2. Also is there some other way to achieve what i am trying? please note here i do not want to use high level existing frameworks such as tabletop manipulation and other related kinds.

Observation - the above code causes the gripper/wrist to rotate perfectly along x axis(Roll).but i cant make the gripper point downwards.

1. There is a problem with Optimus and Ubuntu at the moment. Some laptops allow you to subvert Optimus via the BIOS, but some don't. I've heard of some projects that attempt to fix these issues. I believe its called Bumblebee.

2. There's no officially supported 11.10 repo listed on the site. I can't imagine one will be made available until the official release of 11.10. Also, the Optimus problem is with the Nvidia drivers for Ubuntu in general, not 11.04 specifically.

3. I've read bad things about the Dell M14X on Ubuntu 11.04. You can do a quick search on Google to find out more, but I believe that Optimus is the main cause of the issue. After installing the Nvidia drivers, many people can't even boot back into Ubuntu at all.

4. As for brands, I'd look into Asus. We run all of our simulation and visualizations on an Asus G53J. It sports an Nvidia GeForce GTX 460M, and it works great. I've read that many high-end Lenovos run Optimus too, but I believe that they have a BIOS feature to disable the integrated card, and thus eliminate the problem (who needs an integrated card anyway?).

Ok sorry for seemingly double posts --- but they r quite different questions -

1. is there some problem with ubuntu 11.04 not being able to support graphics card with optimus technology ??
2. Does 11.10 solve that problem and does ROS diamondback have a 11.10 repository?? :P
3. Thinking of buying a dell m14x(with nvidia GT555m card) - any idea if rviz and gazebo will work on it??
4. All dell laptops seem to have optimus (and are freaking costly) suggest any other good brand on which i can happily work with ros gazebo and rviz.

Thanks.

Well, I'm not sure if there is a list of system requirements for Rviz floating around, but I found a list of Gazebo System Requirements that gives you a broad overview of what kind of hardware would be needed for the more complex graphics proecessing.

As for your Rviz problem, I've searched around and found this page Rviz Troubleshooting that explains two possible causes to your problem. Either your card does not support OpenGL or you do not have the correct graphics drivers installed (or both). For a new laptop, I would bet that you'd be safe with most modern GPUs. If the GPU supports OpenGL, you're probably ok. You can get a laptop with a dedicated GPU for very little money nowadays.

If it helps, I can run Rviz on Intel Integrated GMA HD graphics in my laptop, but I also run it on other machines that have Nvidia 560M, Nvidia GTX 260, etc. I hope that helps. If not, I might be able to find some specific models for you.

hey guys,

I am a complete newbie at ROS (specifically for pr2) just started this week. So after the installations and having some fun with gazebo, following the tutorials i came across rviz. Now the problem i faced was when i did "rosrun rviz rviz" and added a robot model it freezes the whole system (this happens only with the robot model i can add everything else), anyways after researching these forums along with wiki's i realize its the problem with improper intel on board gpu drivers (which i have on my dell studio 1555) ----- Sooo now finally the main question --

1. can you please specify some sys req's for a new laptop on which i can smoothly work with rviz and gazebo.
2. Also if possible let me know which brand of laptop and stuff :D ...

Thanks guys - not just for answers to this - this forum on the whole has helped me out a lot since the past week hopefully after sometime i can return the favor by helping others.