# Wheel with high torque causes slipping with highest friction coefficients

I am trying to model a car in Gazebo. The mass is about 2000kg and the wheels have a diameter of .356 meters.

Based on the max acceleration of the real car 3 m/s^2 it would require a force of 6000 newtons or a total torque on the wheels of 2136 N*M. Split among its two front tires that is a max of 1068 each.

I modeled the car (ford escape) in Gazebo using realistic dimensions and weight, when I apply 760 N*M of torque each (Using AddTorque on a Link with a plugin) it works up until about 3.5 m/s then the wheels begin slipping.

My model is using:

       <collision name='front_right_wheel_link_geom'>
<pose>0 0 0 0 0 0</pose>
<geometry>
<cylinder>
<length>0.229</length>
</cylinder>
</geometry>
<surface>
<bounce>
<restitution_coefficient>.2</restitution_coefficient>
</bounce>
<friction>
<ode>
<mu>1</mu>
<mu2>1</mu2>
<fdir1>1 0 0</fdir1>
<slip1> 0</slip1>
<slip2>0</slip2>
</ode>
</friction>
<contact>
<ode/>
</contact>
</surface>
</collision>


As well as placing it on a plane with max friction and no slip.

Is there any other parameters I can try to get this working?

(Using Gazebo 1.5 that ships with groovy)

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To get better friction solution, try increasing number of inner iteration in the physics engine setting. For example:

 ...
<physics type="ode">
<ode>
<solver>
<iters>10</iters>
</solver>
</ode>
</physics>
...


Note also gazebo 1.9 does the iterations on friction directions last, resulting in better solution than gazebo 1.5.

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