<?xml version="1.0" ?> <sdf version="1.5"> <model name="ball_bearing"> <link name="link"> <pose>0 0 0.003 0 0 0</pose> <inertial> <mass>0.0011</mass> <inertia> <ixx>3.96e-09</ixx> <ixy>0</ixy> <ixz>0</ixz> <iyy>3.96e-09</iyy> <iyz>0</iyz> <izz>3.96e-09</izz> </inertia> </inertial> <collision name="collision"> <geometry> <sphere> <radius>0.003</radius> </sphere> </geometry> <surface> <contact> <!-- stainless steel 18-8 material properties --> <poissons_ratio>0.305</poissons_ratio> <elastic_modulus>2.0e+11</elastic_modulus> <ode> <kp>100000</kp> <kd>100</kd> <max_vel>100.0</max_vel> <min_depth>0.001</min_depth> </ode> </contact> <friction> <torsional> <coefficient>1.0</coefficient> <use_patch_radius>0</use_patch_radius> <surface_radius>0.01</surface_radius> </torsional> </friction> </surface> </collision> <visual name="visual"> <geometry> <sphere> <radius>0.003</radius> </sphere> </geometry> <material> <script> <uri>file://media/materials/scripts/gazebo.material</uri> <name>Gazebo/Grey</name> </script> </material> </visual> <!-- approximate rolling friction --> <velocity_decay> <linear>0.00</linear> <angular>0.005</angular> </velocity_decay> </link> </model> </sdf>