Robot Inspiration Series #3: Self-Balancing Wheeled Robots - Part 2

Kirk Backstrom did an excellent post on Saturday about self balancing robots.

One of Kirk's points was that there are a lot of types of robots that can be made with this technology that hasn't been done yet with the NXT - so most people design robots that only balance or move (front / back and turn).

But for me personally, after spending days working on my self balancing bike for the new Idea book, spending a whole weekend tuning the control system of a self-balancing robot is not my idea of fun:

There are many ways you can achieve a self balancing robots even if you dont want to get your hands dirty with low level language programming and heavy control engineering theory. Here are some suggestions on how to achieve a self balancing robots without the complexity of having to implement a balancing algorithm in NXT:

(1) For Segway type vehciles, Make the diameter of the wheel so big that it behaves more like the Hailfire Droid tank wheel. The secret here is to lower the centre of the gravity of what is in between the large wheels - so all the weight is below the wheel axle. Check out my NXT Hailfire post last month

(2) For bike type vehicles, Make the wheels really thick. The secret here is to make the contact surface wider so it no longer behaves like a bike - but more like the Bat pod from the new Batman movie.

LinearActuator has created a pretty good NXT version of the Bat pod. So I got him to do a Guest post about his creation:

NXT BatPod: Guest Blog from LinearActuator

To celebrate the release of Batman’s latest film, “The Dark Knight”, the NXT BatCycle was created! Armed and dangerous, the BatCycle can handle any opponents it may encounter with its’ hidden rocket launcher that expands from the body of the bike. With its’ large wheel area, the NXT BatCycle can also stand and move unaided!

The BatCycle (BatPod) has been designed in terms of style to be as similar to Batman’s other vehicles (Batmobile, Batwing, Batboat, etc) as possible (
Black TECHNIC panels)

For more information on the NXT BatCycle, please check out its' NXTLog page

The BatCycle’s documentation has been split up into four main modules, as well as a small section on the NXT BatCycle’s weapon, and how to construct the black TECHNIC panels from the
TECHNIC Tow Truck (Set No. 8285). An .LXF file of the basic construction of the BatCycle as well as a basic program, have also been provided on the NXTLog page for this model.

Edit: Video as requested:

NXT BatPod:

The real BatPod from the new Batman movie, Black Knight:


Anonymous said…
Aren't you linearactuator? Why is this a guest blog?
Anonymous said…
This comment has been removed by a blog administrator.
BlueToothKiwi said…

No, I am not LinearActuator. LinearActuator is my 14 year old son.

If you got something interesting to say, and you think it is worthwhile having its own post (as opposed to a thread in a NXT forum) then fee free to approach the bloggers here to do a Guest post for you.

If you are lucky, and if your contributions are good, you might get invited to be a regular contributor.

Tim [BlueToothKiwi]
Anonymous said…
That will never be able to balance itself once it starts moving - Do you have a video?
BlueToothKiwi said…

Video posted as requested.

The trick is to limit the steering to 10 degrees either side of middle - and reduce the speed while turning - and the vehicle wont fall over.

The video does show it falling over when it went over a bump.
Anonymous said…
Nice video.

My favourite bit is the bit where it fires the missile!!
hassenplug said…
Maybe I missed it, but I don't see it doing any turning in the video. Do you have any video where it actually turns?

BlueToothKiwi said…
You are right Steve - it does not show any video clicks of it turning - but it is a bit late to add that to the YouTube video.

Watch this space - for a link to a new video.
LinearActuator said…
Steve, a video of the NXT Batpod being autonomous and turning has just been uploaded and can be found here:


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