View Full Version : Transmission simulating gizmo

16 April 2012, 1308
While on the "throne of elevated thought" I got a idea and wondered if you peeps might be interrested.

Basicly you have your average throttle pot, a microcontroller and a two pole switch for switching "gears" up and down.
What the microcontroller does is to simulate a transmission via a amount of restriction of the pot signal from the throttle unit depending on the selected "gear" and settings for that gear.
Basicly when in first, the microcontroller limits your pot signal to match a certain setting and or speed, spacing the signal needed to reach that point over the full turn of your throttle. When "up shifting" to second the limit shifts up as well to simulate the transsition to a higher "gear."

This should give you greater fine controll over your speed at any given point and make certain that you don't "blow your budget" ;) (..depending on the selected amount of gears and the setting of these.)
A few desirables might be a speed censor to match a desired speed in a gear and or the option to select the amount of gears and the settings of those to suite personal taste.

Via variable current limit of the controller (I vaguely remember some having this feature) you might even approach the full feel of a transmission, potentially upping your range. This is however just a theory.

Obviosuly a bypass switch would be mandatory no matter what so you could gun it without being restricted at any point ;)

What do you think, a nice gadget or vaporware?

ARC EV Racing
16 April 2012, 1410
Sounds interesting as a project, although I'm not sure of the practical benefits. It wouldn't be difficult to program a Curtis running VCL to behave the way you describe - I can help if you like.

17 April 2012, 0312
Sounds like a waste of time trying to merely simulate the feel of a gearbox. You'd be better off developing a box that sits between the throttle and controller which controls and limits the throttle signal into the controller. The controller would be set up to run at whatever maximum voltage/current/acceleration you need. The box between throttle and controller would then control the speed at which the throttle opens and the amount.

For example, you could have a 'learner' mode which scales the throttle input down so that when the throttle is fully open the controller only 'sees' 50% throttle. You could also control the speed that the throttle appears to open so if you bang the throttle wide open the control box would translate this into a more gentle acceleration curve. You could even create a simple traction control system if you had ABS sensors on both wheels. If the speed difference between the wheels rapidly changed this could indicate loss of traction so the control box would cut power briefly.

The advantage of this system is that it would be compatible with all controllers as you wouldn't need to communicate over RS232/CAN bus/whatever. It would simply sit between throttle and controller, and only control the throttle input.

A real gearbox on an electric bike allows you to select a gear to suit the riding conditions, and therefore give your batteries an easier life. For example, if you have an electric bike with a gearbox that has a max. top speed of around 80mph but you were riding around town at no more than 30mph in stop/start traffic then you'd use the lower gears. This would give you good acceleration from standstill, you'd still have reasonable top speed, and the load on your battery pack would be lower. If you then take the bike on the motorway/freeway you'd work your way up through the gears until you achieve top speed.

17 April 2012, 1235
Simulating the feel of a transmission was not meant to be a main goal, as much as a "feature." Bad translation on my part.

The main idea is excactly as you described Mark. Traction control could be really cool to implement, although potentiallly complicated. Building on the idea of custom acceleration curves, the ability to vary the aggresiveness of said curve could be desirable.

Learners modes with custom acceleration curves, traction control and potential maximum speed matching for each mode.. sounds cool to me. :)

11 March 2013, 1943
I also thought that simulating the feel of transmission within the throttle cable, could give a lot more precision for each speed.
Without said transmission simulator, I figure that when the vehicle is cruising at a given speed, the throttle is always in the same position. Which implies that if your gear ratio is set for top speed (throttle @ 100%) your vehicle is doing 200mph. I would have thought that even if you had a powerful engine to give some measure of city driving (slower speeds), the throttle would be so sensitive down at those slower speeds. Hence why a simulated throttle response of 1st or second gear would be nice, as the throttle wouldn't need to be as sensitive, as you know you don't need to go past city-limits speed.

I tried to be as succinct as possible, and as I haven't ridden an electric motorcycle/vehicle, I am just giving my suggestions.

I figure throttle response for each simulated gear, the throttle has more resolution and henceforth much greater control.