I created a slide that changes its inclination from 0 to 30 deg per second in order to measure static friction in gazebo and its relation with mu1 and mu2 coefficients. The coefficients defined for the experiment were as follows:

<gazebo reference="slide_link">
    <material>Gazebo/Black</material> 
    <mu1>0.9</mu1>
    <mu2>1</mu2>
    <kp>100000000.0</kp>
    <kd>1</kd>
    <fdir1>1 0 0</fdir1>
</gazebo>

<gazebo reference="sliding_box">
    <material>Gazebo/Red</material> 
    <mu1>0.6</mu1>
    <mu2>1</mu2>
    <kp>100000000.0</kp>
    <kd>1</kd>
    <fdir1>1 0 0</fdir1>
</gazebo>

When I run the simulation, the sliding box slides to the top first and then slides down to the ground. I cannot get the sliding box to behave like a regular object, which will slide down when the inclination point to overcome static friction is reached. It looks like there is a centrifugal force acting on the object that makes it slide to the top first. How do I solve the problem? Please help.