Drifting Turbo Trike
After seeing RatBots cool drifting moves I wanted to try caster wheels. I had a Ducted fan lying about from an experiment gone wrong (prior to joining LMR) and thought that it might make for an interesting combination with the casters. I was going to remote control this but have had trouble catching up with my brother to borrow some radio gear. If I get a chance I'll post a video of it being radio controlled.
The first video is just an engine test. Alternating between 0 and 100% thrust. It definately has enough thrust to pick up a respectable speed.
The second video shows the trike under radio control. This is no longer a robot since it has proven too uncontrollable to be autonomous.
The third video isn't as exciting, just a different camera angle.
This is what I've got so far: A meccano chassis although it could easily have been paint sticks, lego etc.
The electronic speed controller (yellow) is mount at the base close to the fan. The battery fits neatly on top.
Because the motor / controller can draw in excess of 20A I'm using a pair of FETs in parallel to switch main power. This is a bit of overkill as one FET would do. The switch was originally buit for BoozeBot. When I turn on the low power circuit for the 28X1 a signal then turns on the FETs. In effect they are a solid state relay.
The ducted fan did not come with any specifications but when run off a car battery at less than full power, the blades streched enough due to centrifugal force to gouge out the ducting. At full power it probably would have destroyed itself. The 7.4V battery seems about right.
My caster wheels are a bit heavy being solid rubber. I will probably change them later to a lighter plastic caster wheel as the reduced momentum will improve responsiveness.
I've attached the speed control instruction sheet. It can be a little bit confusing at first as it has many programable options. I've had problems reprogramming it via the 28X1 and get many error codes. Last time I used it with a dedicated circuit to imitate radio control gear with no problems. It seems the twitchy servo outputs of the picaxe processors confuse it as the most common error message is "throttle signal is irregular".