McDonalds definitely invests in automation, but the goal isn't to replace humans entirely. Uber also has much higher marginal labor costs than McDonalds does and would benefit a lot more from automation.

Examples of automation at McDonalds:

Self serve order kiosks http://www.businessinsider.com/what-self-serve-kiosks-at-mcd...

Automated beverage dispensers https://www.youtube.com/watch?v=k26g3YqAsfA

Digital menu boards that update based on conditions http://www.eater.com/2015/11/11/9716058/mcdonalds-weather-me...

And then of course all the tech in their kitchen that take out all the guesswork (timed friers and the like).