Correct caster effort/velocity limits in URDF (ros ticket #5031)

[ahendrix]

The caster effort and velocity limits in the current URDF are very high. Although this can't cause a problem on the PR2, these limits should be corrected for simulation.

Caster wheel limits:

• effort = 7
• velocity = 15
• k_velocity = 10
• damping = 1.0

Limits for the turret should probably be similar. Actual max velocity of the PR2 caster wheel is around 10, max effort is around 6.5.

trac data:

• Owner: hsu
• Reporter: watts
• Reported at: Wed Feb 16 20:53:27 2011
• URL: https://code.ros.org/trac/wg-ros-pkg/ticket/5031

[ahendrix]

[hsu] r54829.