Meet Ubbo: an open source telepresence robot that lets you attend meetings from a remote location. It can go for up to 4 hours without charging. The robot has mecanum wheels and uses a tablet to let you see and be seen. You can add additional sensors and attachments to do more with the robot.
Ubbo is fully open source with a base controlled by Arduino or Nucleo boards. It communicates with the tablet via Bluetooth. More info is available here.