And now for something entirely different…

Posted on October 17, 2009


I’m sick of cars. Fed up with traffic, stress, and pollution. It makes no sense to drive a four-seater alone everyday.

This summer I’ve come to realize something: cars are the past. The future is in flexible personal mobility. And I’m not one to live in the past. 😉

I had already read a thousand times in a thousand places that the way to go is to invest in public transportation and good inter-modal terminals, but that took a long time to actually sink in. So, stopping short of buying the expensive but fantastic (and pedal-less) Yikebike or the fantastically expensive eRockit, what can I do?

I actually bought my first Hybrid Electric Vehicle: a plain chinese e-bicycle (I’ll blog about it later, in depth). With it, I can go to work every day and deliver my kid to school as well. I was incredibly lucky that my township finally implemented the bicycle paths in time of my life-altering decision, and they are actually useful to me. It is a ride we both enjoy very much, and allows us to experience the pleasures of silence, fresh air, and natural beauty while we cross the green zones of our city. I get about 30km day average out of my lithium batteries and legs while leaving the gas-guzzler in the garage, so that part of my mission is accomplished. 🙂

But just because I’ve solved my mobility problem with a ready-made human hybrid, that is not the end of this project. I’m still developing MyOwnHybrid. It’s just not a car any more.

There’s been a lot of interest recently in 3-wheeled vehicles. I was initially prodded into it by another EV project developed here in Portugal (the Veeco roadster), whose owner is contemplating a 3-wheeled version. I like the 2-wheel-in-front layout a lot, because it is fundamentally stable in curves – the weight gets thrown onto the outer wheel, enhancing traction where it is needed.

Then my friend John told me he would very much like to see his wheel motors in trikes, because he also believes profoundly in the vehicle type as a solution for urban commuters. We shared a few basic ideas, I pulled my engineering friends’ wits into it as well (NJay helped a lot), and a fantastically new and bold  innovative design was born.


This design is so bold, in fact, that it seems basically infeasible – unstable to the point of being unsafe. So, to make sure the thing can actually be built and used in everyday life, I’m doing a phased approach and building some “proof-of-concept” models before the final prototype. Whenever a concept is approved, the next one gets designed and built. Think big, start small. 🙂

The basis of my trike design is the “differential steering”. Instead of doing a mechanical steering system like everybody else does, I’m fixing the 2 front wheels in a straight position, and steering the trike by giving them different speeds. Turn left by speeding up the right wheel, and vice-versa. The rear wheel is left to turn freely (a “crazy wheel”), and that’s what makes this vehicle so special (and potentially dangerous). It’s got an enormous manoeuvrability and should be very fun to ride. If you can keep it on the road, of course. 😉

At school, the 3rd semester has started, and there is a course on “Electric Traction and Vehicles” that aims at the physics of wheel-to-ground interaction and electric traction stability and control. My teachers are quite delighted with my small project and materials and know-how are already being thrown in. I wish I had more time to work on this… it’s going too damn slow. 😦

Enough talking, let’s have some pictures. Here is my very first life-size proof-of-concept build, affectionately called the “soapbox”.


If you’re wondering where the wheels and motors came from, I’m using materials I scavenged from a couple of e-scooters that Hotrod found in the garbage (literally!). With a little machining and creativity, the “soapbox” concept was born.


It is built to prove one thing only: that a steering-less DiffTrike can actually handle real-world rides in safety (and still be fun). I’ll be developing the electronic control on this lump of boards. Right now each wheel is controlled directly by a hand accelerator, which is really fun for a test pilot but not very practical or safe for everyday life.


I’m still waiting for the machined cog wheels for the right side wheel transmission. Once I get that, it’s soapbox derby madness time! 😉

This is the left side wheel transmission I had to duplicate on the right side wheel:


And here is a close-up on the accelerator/brake levers I came up with for this contraption:


The brake levers are facing backwards because otherwise their weight stops the accelerator levers from returning to their upright position. 😉

This is crazy enough to have potential. Videos are coming, I promise. 🙂