I hope that your browser can translate English to Korean well, as unfortunately I do not speak Hangul
Instead of using another Dynamixel Shield, I would like to suggest another approach whereas all your DXLs are powered by a separate Power Supply using your regular TTL or RS-485 cables as normal. Make sure that this PS can handle all the current output needed by your DXLs. Basically, this becomes an Independent Dynamixel Network (let’s call it Network A).
Are you using TTL or RS-485?
Then you use a second power supply or battery to power your UNO and Dynamixel Shield and have them connected together as normal also.
Next, and this is a critical step, you need to use a single (and special) TTL or RS-485 cable to connect between one of the DXL Connectors on the Dynamixel Shield to Network A. And this cable is special because it needs to have its VDD wire severed - so that the PS on the UNO is isolated from the PS used for the DXLs. However, they remain connected at the same ground node.
Basically, the UNO + DXL Shield sends low voltage/low current CONTROL signals to your DXL communication ports, but your DXLs get powered by their own and bigger PS.
Good Luck with your project!