[POC] Electronic differential with Powered Up app

[ord]

Using the controller GUI in the Powered Up app, it is possible to remote control a vehicle with electronic differential.
 

 

w = wheelbase
t = track
v = velocity (of virtual motor in centre of vehicle)
a = steering angle (+/- 30°)
r = turning radius

A = steering motor
C = left drive motor
D = right drive motor
 

The theory:
https://www.researchgate.net/publication/224184352_Ackermann_mobile_robot_chassis_with_independent_rear_wheel_drives

Edited January 13, 2020 by ord

[Didumos69]

Nice proof of concept! Thanks for sharing.

Edited January 13, 2020 by Didumos69

[TeamThrifty]

Brilliant. The uses for this are endless... I'm already thinking about Fendt tractors that use separate hydrostatic motors for front and rear axles. Its analogous to using two motors with the speeds corrected for the wheel sizes, but more interesting is that they use 'pull in turn' to get the front axles to run faster and tighten the turning circle. All possible with the Powered Up app.. Awesome concept.

[sirslayer]

Some tutoring on using the Powered Up app was bad enough but what you shared @ord was very important.. Good job!! 

[ord]

Thank you all for the kind words. It should be noted that the steering requires a ~0.2 second delay to function properly is buggy in this version of the app (3.0.0), making it impractical to operate. Hopefully something that gets fixed in a future update.

Edited January 14, 2020 by ord
Correction

[kbalage]

@ord about the steering - whenever I use the block you used for steering with the PU L motor and try to control it with the slider interface, there's a constant left-right trembling of the shaft. Depending on the speed set in the block the frequency of the trembling changes but I cannot eliminate it. I tested this with both the iOS and Android versions of the app and on 2 different hub/motor combinations but it's always there. Did you experience this?

[ord]

@kbalage I experience that when controlling the motor directly with the slider but with a variable in between, as above, it seems less pronounced and can even stabalise. Still, it is far from usable. 

[kbalage]

@ord I also tried to use a variable, even tried to round the position of the value to 10s but that did not change the constant trembling. If the motor position controller block is in a loop then it immediately starts the trembling, even if it has a constant value set.