No. Ubuntu uses Linux, which is not a real time kernel. Although you might be able to start from an Ubuntu system and modify the kernel so that it does meet real time guarantees, I don’t think it would be correct to say that Ubuntu is a real time OS.

Is Linux a RTOS?

… making Linux just a little more fun! A real-time operating system (RTOS) [1] is an operating system capable of guaranteeing timing requirements of the processes under its control. While a time-sharing OS like UNIX strives to provide good average performance, for a RTOS, correct timing is the key feature.

What type of operating system is Ubuntu?

Ubuntu is a complete Linux operating system, freely available with both community and professional support.