cob3-5 has a powerball tray with 3 joints: tray_1_link, tray_2_link and tray_3_link, the reference positions are:

	<property name="def_tray_1_ref" value="0.0"/>
	<property name="def_tray_2_ref" value="0.0"/>
	<property name="def_tray_3_ref" value="0.0"/>