So this is my situation I'm 3 months into my 2nd year of a Computer Science PhD and I've come to the conclusion that I just shouldn't have started it in the first place.

I did my undergraduate degree at the same university and was approached by my undergraduate thesis supervisor to do a PhD. My department does mainly theoretical work which isn't really my taste, robotics has been a hobby of mine even before I started university so I wanted to do something more practical. It turned out that my supervisor and one of his colleagues had been wanting to do some robotics work so it seemed like the perfect match.

I wish I'd had the wits to see how wrong I was but sadly I didn't. My supervisors are both nice people but they have no clue what they are talking about I spend most of the time in our meetings explaining things to them and the only advice they can offer is very vague and not at all helpful. I also found out a year in that my primary supervisor really wanted to do something related to my undergraduate thesis and didn't really want to do the robotics project that was just the hook to get me to apply, he hoped I'd give up and go back to my previous work (which was interesting but not something I'd chose as PhD topic).

To make matters worse I've had no lab space to work in so have been trying to run experiments in lecture rooms (between classes and out of hours). And considering I'm working with small flying robots is pretty ridiculous. Many an hour has been wasted on repairs from collisions with furniture/projectors etc.

I started with the goal of learning more about a field I really love and getting a PhD, and I'm quite happy with my progress on the first goal I've learnt a great deal and am really proud of the skills I've been able to develop. I just don't know if I can finish my PhD.

I don't have experience of robotics but I'm in the third year of a science PhD. I applied for an advertised project which looked ideal for my interests and then when I started in the lab it turned out to be an entirely different project. Similarly, my supervisor took me on because I had experience of the techniques required for this other project that I had no interest in, so I felt a bit conned to be honest. I stayed because my supervisor kept promising me that I could start the advertised project later on, and now I've found out I won't be working on the interesting project at all. Anyway, the point is, it's rubbish when that happens but unfortunately it does happen, but if you can accept that your PhD will be this theoretical project and not the robotics practical one, then you can still get your PhD. It's not ideal but you say your supervisors are nice people, so can they help you in other ways, such as giving you feedback when you come to write up, etc? Also you've mentioned that you do love your field, which is also good because this can be a long slog and you need some enthusiasm for your subject to get you through.

As for the lack of lab space, is this something you can talk to your supervisors about? It's not unreasonable to request space to do your experiments, and if they're not helpful can you try the postgrad research office at your university? They should be able to hound your supervisors to provide you with necessary lab space if they don't listen to you in the first instance.

I'm not persuading you to stick with the Phd or quit - that has to be your decision, but you have mentioned a few positive points about the PhD. I sympathise with being given a project that is of no interest to you, but it's worth weighing up whether you'd be worse off elsewhere. Best of luck!