mecanum wheels side move get slow and shake

Hi all, now i simulated the mecanum wheels in gazebo by simulate one hub and 12 free moving rollers, it's working but when go to the side move(side left, side right), the performance was not good, it move slowly and shake to left and right direction, i assumed that it is because of friction between plane and rollers, but i changed the <mu1>1</mu1> <mu2>1</mu2>of each rollers , it does not work.. Can someone give me some suggestions about how to fix that?

Thanks in advance!

Shengnan Chen

Asked by shengnan on 2016-06-29 09:27:50 UTC

Comments

can you provide a video of the behavior and the sdf of the robot? Mecanum is complicated, so we need to see the actual model to help

Asked by Peter Mitrano on 2016-07-01 18:07:48 UTC

Hi, i uploaded the video for the mecanum wheel in: https://youtu.be/Tk4dH-iZeE8 friction parameter: hub joint friction is 0,1; 12 roller joint friction is 0,2; friction between rollers and ground is 10.

Asked by shengnan on 2016-07-07 06:20:29 UTC

And i use the URDF file (https://www.dropbox.com/s/znuc87zbbmcd50h/omniwheel.urdf?dl=0), use gazebo-ros-control to control the joint following the turtorial: http://gazebosim.org/tutorials/?tut=ros_control

Asked by shengnan on 2016-07-07 06:31:31 UTC

Answers

I'll update this answer as you provide more info and I find more things, but for starters the mass and inertia on your rollers is wrong. You can approximate them with cylinders using an equation like the ones from here. You could also use meshlab or a cad program to give you them.

some useful info on friction

I'd also recommend setting implicit_spring_damper true for all joints. Also, I'd add a very small amount of damping to all joints, .01 or so.

This URDF isn't much help without the meshes, so you should zip everything (including model.config) up and then we can test it out

Asked by Peter Mitrano on 2016-07-07 10:54:32 UTC

Comments

I was having the same problem.

Can you see a side-view of your mecanum wheel? If the rollers are cylindrical, the side profile of the mecanum wheel is nearly octagonal, which causes the robot to move jaggedly. The mecanum rollers need to have a curvature to them, to cause the mecanum wheel to be nearly circular.

Properly curved mecanum roller: image description

Properly ciruclar mecanum wheel: image description

Asked by K88 on 2022-10-07 16:30:35 UTC