Can I install ROS1 kinetic and ROS2 crystal on same pc? I am using Ubuntu 18.04 LTS, 64-bit.
The short answer would be (for your stated configuration): no, as Kinetic is not supported on Ubuntu Bionic (only on Xenial (16.04), see REP-3). The ROS buildfarm does not build any Kinetic packages for Bionic because of that.
The longer answer would be: maybe.
It might be possible to build Kinetic from source, but there will probably be significant incompatibilities to overcome, such as those with Qt (4 vs 5), Ogre and potentially Boost.
An alternative to building Kinetic from source could be to use a Docker (or Singularity) image of Kinetic (such as ros:kinetic
or osrf/ros:kinetic-desktop(-full)
).
Technically, that would not be an answer to your question, as it wouldn't be exactly running on the same PC / OS, so depending on your requirements / use-cases it wouldn't actually help you.
A second alternative could be to install ROS Kinetic on Ubuntu Xenial and build ROS Crystal from source next to that. REP-2000 lists Xenial as a Tier 2 platform (here) and apart from some of the RQT plugins, Crystal should still compile on Xenial last I heard.
I have projects on ROS Kinetic [..] and I am using Ubuntu 18.04 LTS, 64-bit.
Btw: this confuses me, as Kinetic cannot be installed on Bionic. Are you already using containers?