Simulation of mechanum wheels
I am trying to simulate behavior of mechanum wheels in gazebo 2.x (default installed with ROS Indigo). I am facing difficulties when defining constrains on the joints of the rollers.
I want to check influence of wheel velocities to debug my kinematic model. I am simplifying the elipsoid shape by just assuming cylindrical links and contacts. Rollers of each wheel (8) have 45 degrees rotation with repect wheel rotation axis. I am defining the model in SDF 1.4 so no fixed joint is supported.
To connect the wheels to base there is no problem I just define a revolute1 joint. To define the rollers it comes the tricky part. At first I define individual position of rollers (cylindrical links) within respect the base and defined the revolute 1 joint with respect the wheel they belong.
In static it looks ok and also when visualizing the joints in gazebo. When testing with static false and applying torque to wheels, after some small value the rollers starts to make 3D rotations with respect the fixed position of the roller in each wheel.
I tryed to implement a shaft in each roller that would be 3 axis constrain with the wheel with a revolute joint and same problem arises.
I was wondering other opinions on how to solve or attack this problems.
