Speed Buggy

Sometimes the best way to test an idea is to just go ahead and build it!

Attached are some photos (and a link to a short video) of a failed project I called “Speed Buggy.” The idea was to link 6 motors into an AWD / power-sharing configuration using 8 differentials. In the video, you can see that power can be diverted forward and backward along each side as well as across the chassis. If one wheel stalls, the others take over. That aspect works great.

I used a gear ratio of 2:1 from the motor to the differentials, which gives the drive train plenty of speed, (see end of video) but not much torque. :frowning:

Sadly, after just a few minutes of powering 6 motors simultaneously, the battery becomes quite drained and often overheats. So, the 8 differentials worked fine for combining power for raw speed, but were not very powerful or practical. In the end, I was not very happy with the final outcome.

To improve this design, I would isolate the motors on each side and program them to spin at different speeds based on the buggy’s turning radius, which could be derived from the position of the steering motor.

Of all the things I tried, I like the idea that the motors can be turned slightly to accommodate the cables and still keep them tightly packed. Definitely going to use that idea again! To turn the motors, I simply applied the concept of the isoceles triangle and used the axle shaft of the motor as one triangle vertex. Then I shifted one of the motor’s outside pins (i.e. not a center-aligned pin) from its expected hole to the one across from it. Because both are the same distance from the motor shaft, the pin lines up perfectly. With different configurations of gears, this method of adjusting the motor from the standard 90-degree positioning should allow for many other intetesting design modifications.

Video link:

Thanks for looking!


An interesting model, I would like to see it in motion.

Movement crab, in the 8 minute of this video, tried to realize something like that?