I died 4-5 times before killing it, this is how I did.
First I just charged in and killed those small tanks around him fast, not even bothering about the big one firing at me. After that I retreated up to the ledge where the energy tanks and other VS are located. Near the right end of that ledge is a couple of pillars in the floor below. I found out that if I went there and moved around in small steps to left and right (without leaving the area on the ledge close to the pillars) I could get the tank to move back and forth between the pillars over and over. This makes the tank shoot his rockets and stuff into the pillars so you dont get any damage, and between his shots you sidestep a little and take a shot or two at him, then go back so the pillars covers you. Just make sure to always move to the sides so the pillars is in the tanks line of sight all the time, except when you want to shoot back, and he will die sooner or later. I didn't even had to change to the other VS there
Something else I noticed before I found out this tactic was that there is a grenade launcher lying where the tank is driving around. I usually doesn't use the grenade weapon as I think it kind of sucks, but when I used it against the tank I saw it did considerable damage to him! Dunno if that weapon is always that powerful or if he is vulnerable to it, but it was far more effective than the rocketlauncher and other weapons in the area. Too bad you only have 10 shots of it though, but they will make good damage to him.
I was also really close to killing the tank just by constantly jumping/flying around and unloading all I got at him at all times. Then when the VS broke I just ran and grappled to the ledge and fetched myself a new VS. You only have two extra VS there though so try to avoid fire as much as possible (kind of obvious