Self collision problems

[yoggi56]

Hello everyone! I'm trying to load URDF-file with URDF_USE_SELF_COLLISION flag:

self.robot = self._pybullet_client.loadURDF( "robot.urdf", INIT_POSITION, flags=pybullet.URDF_USE_SELF_COLLISION)

But when I do that, robot links start trembling. Without this flag, the model works fine (except of self collisions). Can it be because of using STL or DAE-files in collision parameters of URDF? For example:

<xacro:property name="mesh_addr" value="package://robot_sim/urdf/meshes/"/>
<link name="body">
      <visual>
        <geometry>
          <mesh filename="${mesh_addr}body.stl" scale="1 1 1"/>
        </geometry>
        <origin rpy="0 0 0" xyz="0 0 0"/>
        <material name="silver"/>
      </visual>
      <collision>
        <geometry>
          <mesh filename="${mesh_addr}body.stl" scale="1 1 1"/>
        </geometry>
      </collision>
      <inertial>
        <origin rpy="0 0 0" xyz="${body_cog_x} ${body_cog_y} ${body_cog_z}"/>
        <mass value="${body_mass}"/>
        <inertia ixx="${body_ixx}" ixy="${body_ixy}" ixz="${body_ixz}"
          iyy="${body_iyy}" iyz="${body_iyz}"
          izz="${body_izz}" />
      </inertial>
    </link>

Or may be here could be other problems?