TMZ Hip Hop obtained new court docs filed by Young Thug's lawyers on Monday -- calling for the outright disqualification and/or recusal of Judge Ural D. Glanville ... who's been handling his criminal case in Atlanta.

The incarcerated rap star's reasoning is about the same as that of his attorney Brian Steel -- who was held in contempt recently for questioning whether the judge had possibly engaged in misconduct.

In case you haven't heard ... Judge Glanville was suggested to have held a secret ex parte meeting with defendant Kenneth "YSL Woody" Copeland -- but not in the presence of others, which Thug and co. are crying foul over.

The judge didn't deny the meeting took place, BTW -- he simply tried to throw Steel in jail for not revealing how he knew about it in the first place. So on the merits ... no one has really ruled one way or another -- and now, YT is forcing the issue with this motion in court.

Thug is also pushing for a mistrial ... which he hasn't had much success in doing thus far. Meanwhile, Steel will remain free while his contempt of court charge is getting appealed.