Some questions and suggestions:
Hi, Got some questions for you.
1) Which country are you in? For example, if your in the UK, you couldn’t use Santosh’s advice on the wireless - not allowed to use 433Mhz for this task in most countries.
2) Why do you need 4 wheel drive? It’s a pain to produce and harder to code for, and doubles the noise in the system. From what I see of the track, a single motor is more than enough for power - your going to be fighting for weight as it is, and 4x batteries and 4x motors doesn’t add any value.
Your plans for steering are going to add a LOT of complexity - the task your trying to do is a simple one mechaniocally, it’s the coding and the electronics that are hard - keep the vechicle itself as simple as possible.
3) What dimensions are your bot? if it’s mm’s it’s tiny, but cm would give an odd shape.
4) If you want the steering to be responsive, you need to design from the track width upwards. Start with the width of the track. Have the vehickle maybe 3/4rds the width of the track - unless it’s a wide track - if it, just make the bot nice and flat and low. If your jumping, the bot should be as flat as possible.
5) Unless it’s a very narrow track, I would not use differential steering, just normal ackermann - use a servo to move the front wheel, and put power the the back wheels - the fronts stay free revolving. But… Do think about linkage design - ackermann does need a bit of planning.
6) How do you plan on working out where the car is positioned? For example, lets say you have a controller in your hands, and you add a direction that says “Go left”. How are you planning for the vehicle to know what “left” looks like? A dumb system like an R/C car ( When you get the specific PWM pulse, move the servo +ve 50 degrees ) or a relational system where you would want gyros or similar?
7) When you say “none of the parts should be ready made” what exactly is the scope of this. For example, your 99.99% certain to need to gear down the output from the motors - do you have to make your own gear trains? Does an Arduino board count as ready made?
If this was me, I would start from the track, and that gives the dimensions of the car. You want it nice and low and wide, with the weight near the middle. I would suggest you should keep this as simple and as light as possible initially, as you’ll add more complexity to it as you build out features. I would suggest a single brushed motor for power, single servo for steering. I would also, if the rules let you, use an ESC rather than trying to code your own.
Once you have that, build in features as you need them, but for everything keep aksing yourself the question "Is this actually needed, or am I just making things more complex?"
I don’t mean this to sound bad, but it sounds like your thinking about a “cool” design, rather than a functional one. The functional one will be a lot easier and cheaper to make, and it’s a hard enough thing to do anyway even with that simple scope. When you’ve got the first one working well, you can always make it cooler afterwards.
