Partner always runs away lol

Hi, I'm still new to the game, trying to learn the mechanics. I'm having problems trying to get my first partner to stay on track. Sometimes while following me, he'd go off track and do his own things. That's annoying enough; worst still is when I REALLY need his help to help me take down an enemy pirate, and during combat, he just runs off to a planet - his health is not even below 3/4 of his hp lol

Any ideas why?