Robinson finished Caitlin Casey’s kick to the corner as the Rhinos overturned a 10-point deficit to triumph 20-16 in extra time.
Tries from Caitlin Beevers and Lucy Murray helped drag the Rhinos level before a rare mistake by Shona Hoyle from the kick-off at the start of golden point gave them their winning chance.
Robinson duly sealed a fifth straight Grand Final place for Leeds with her second try to set up a repeat of last year’s decider against League Leaders' Shield winners York.
The Valkyrie were too strong for Wigan Warriors in the first semi-final with Liv Whitehead, Liv Gale, Tara Jane Stanley and Lacey Owen scoring the tries in a 22-6 victory.
The Grand Final will be played at the LNER Community Stadium on Sunday, October 8 at 3pm .