Your approach seems to be technically infeasable. Unfortunately (because of security concerns) Android does not allow you to send a camera feed without a foreground application (You would be able to spy on people).

To make things easier, you could have a workaround that would make your setup significantly easier. Because you are using a Tablet you could start your App in a Splitscreen with the Robot App. People couldbe able to view your App (and you could display Robot Data) and you would be able to capture and send Camera Data. You could look here for a way of implementing the splitscreen!