Well i haven’t finished my first build, but here are some ideas that i’ve while doing it:
Pressure sensitive dead man switch: Something between the trucks and the table that senses if there is weight in the table (up to certain number of force), if there is none, cut the power afters x seconds.
ADAS: control independently the torque in dual drives, help with turning and i think with an accelerometer and some reinforce behavior learning it can nullify speed wobbles
Cruising disconnect: Just power down one motor in cruise mode to help save battery, dunno how much it can help.
Autonomus driving. I think a gps, lidar module and a lot of computer power. Totally useless , but cool none the less.
Trucks to have standardised interface for attaching motor mounts. Just a few bolt holes, nothing too fancy. Although it obviously works, the current solution of using grub screws/etc seems like a bit of a hack. It also doesn’t seem to work if you need good alignment as you would for gear based drives.
Suspension. Currently thinking about a ‘street’ version of a BajaBoard, just needs to be half the weight and cost.
Bevel gears and mounting the motor(s) vertically. Not quite sure why (for science?!), may free up some packaging space behind the truck for that suspension system ;-).
Differential system. Some potential to save money/weight by using only one motor and speed controller, but then I can’t see you coming out ahead considering the work that’d need to go into the drivetrain.
As mentioned above, some form of stability control. Seems like a bit of a waste having two independently controlled motors and not doing something like this; developing and testing could be a bit of work.
Autonomous control of RC vehicles is fun to mess around with but don’t think I’d trust it enough to stand on it. Main problem with that one too is the steering is only based on tilt, throw a servo on there to turn the trucks and it could work just like a big ol’ RC car but again I wouldn’t try standing on it at that point. I built a few little autonomous vehicles, I used a pair of small geared tread hobby kits (like $20 a piece) an arduino and a servo to sweep a ultrasound left and right and would just dodge left if it saw something to the right and left if it saw something to the right. Tried upgrading to a Traxxas as the platform to drive around but the batteries I had were crap and I didn’t understand all this stuff well enough to know how to deal with pumping up the capacity (which I now know just means more cells in parallel) and with low capacity only had about 10-15 minutes of intense autonomous crashing into things since it couldn’t read the ultrasound sensors and decide what to do before it would run into all sorts of things.
Love great scott too, lots of good content and info.
Dead-man switch seems like a good idea, would probably want it independent of the ESC or whatever too though and seems there is mixed reliability issues with the switches used for batteries (perhaps a small robot who’s only purpose is to pull the loop-key).
I’d love to explore this idea but I don’t have the tools or skills to even start a concept. And in some crazy world even a two gear transmission.
So with a differential there could be one giant longitudinally mounted motor.
Also a “come here” functionality where the board would know where u are and drive itself to you. This would require gps in the remote and some steering capability, maybe through torque vectoring with dual drive.
Bushings made of a polymer that can provide variable durometers based on an electrical signal. Soft bushing mode at low speeds, duro increases as speed increases. Kill the wobble but still have a carvy ride at low speed.
Probably worth checking out this thread. Hard to see how you’d make something similar without access to at least a CNC, and probably lathe. I don’t have the skills either, but that wouldn’t stop me from trying.
Ive been kinda thinking about some sort of inline Super Capacitor bank for absorbing excess regenerative braking current to prolong LiPo battery life. I have some ideas on how id do it though I personally have no use for something like this as there are practically zero hills were I live (Illinois) though for someone in say SF, then yes definitely lol. Also as I was talking to some peeps about in a dif thread water cooling your board would be awesome, VESC Motor etc. Also this ones kinda dumb but I think it would look really cool is a Nixie Tube battery monitor.
Oh and also some sort of CO2 Fire Suppression System! You could use like a 12g CO2 cartridge and have it just puncture a hole in the tip and vent into the enclosure if it detects to much heat or smoke. I know there are little smoke detector modules for Arduinos or something on eBay.
Yeah easy to detect the heat with thermistors might be harder to detect smoke with all that wind rushing by. For fire suppression think with Lithium fires best bet is actually using sand bags to cover the battery and get it to quickly exhaust it’s oxygen supply so it doesn’t keep burning (gravity will pose a problem here), haven’t done any testing or anything but from what I gather the fire extinguishers usually can’t completely extinguish them and they end up re-igniting
I suppose you could wrap your batteries in a sufficient amount of sand bags to contain the fire better but without some sort of powder covering it I think the stuff kind of just keeps on going (like the energizer bunny)
Pretty sure we discussed this in another thread reducing the number of motors doing the work is actually likely less efficient and also someone noted the power turning the “idle” motor is still going to be going into the coils and burning up in the mosfets if you aren’t putting it back into the battery (at which point you’re braking while trying to go forwards which is never really going to work out, no over-unity and all)
If you have 1000W going to two motors you have 500W going to each one. If you are at 42V lets say then that’s 500W/42V ~= 12A to each motor, power loss in the electrical components has a square relationship with this current I^2*R (everything before the energy is being used in the coils to move the rotor). If instead you deliver the same 1000W through a single motor the current through that speed controller and motor is double 24A (same current through the lines from the batteries but double the current through the single speed controller and motor to get the same power as two motors).
Beyond electrical efficiency you are putting less strain on each belt and the rest of the drive assembly and have more gripping friction with the two motors pushing… would be good to get some real world results to verify this but all makes sense in my head
Inside the enclosure there isnt any moving air usually and I was thinking more an electrical fire from a shorted wire or whatever. And LiPo’s will obviously keep heating and venting electrolyte even with a CO2 suppression system, though the ideas is to hopefully keep the vapors from igniting which is a lot worse than the vapors themself, at least to the board physically.
Eh mine is drafty you must have a tight box (twhs). Either way though just saying detecting heat is typically simpler than detecting changes in the air. Also with shorts in wires usually from my experience the wire pretty much instantly vaporizes anyhow so time it has to transfer the energy to light other stuff on fire is relatively small, once the cells go up think that’s when you have real problems.
What about attaching batteries and other electronics at top of drop through decks? Like loaded tan tien you have a lot of space for your foot. And with this you wont have any problems with deck flex and clearance.
Also attaching an ultracapacitor between battery and driver. Since ultracapacitors can be charged faster and does not have any charge-cycle limit driver can maximize the amount of electrical charge you can get from braking. And when you need extra power for a short time you can deplete the capacitor, and protect the battery from sudden power surge.