Building mobile pergola

[Tovin]

I am planning to build a pergola similar to the one below. However, I would like to put wheels on it so that I can roll it to different places on the deck.

How do you suggest I build it to make it stable enough to roll?

And what dimensions should I choose for the timber of the pergola?

 

[Surfiesis]

Going through similar thoughts, hoping for many responses.

 

[Hep]

You gave the first answer in a one-year-old thread, so keep your fingers crossed tightly.