Some attributes cause XML file load failure

[XingchenFan]

Hi,

I have my own XML and noticed the block is unable to load it. After deleting various parts of the XML, I have narrowed it down to some extra attributes under joint and actuator, including joint range, stiffness, damping, actuator forcerange. I suspect there are more such attributes that I have not discovered.

A simple test is to add range = "-3.14 3.14" to the end of the joint in dummy.xml. The block will fail to load it.

Any idea why this is happening? And fixes?

Thank you! Frank