[Segway] Parts and links

This a list of basic part needed for building:

Motors

24 Volts, 0.9hp, 40A, comes with gearbox (1:20)

Link: http://www.robotmarketplace.com/products/NPC-T64.html

This is most optimal choice, as can be setup without any extra headache (like gearbox building, figuring out how to mount, etc...)

Wheel Hubs

LInk: http://www.robotmarketplace.com/products/NPC-PH448.html

This hub is fastened to the motor shaft with four inner holes and to wheels, with outer four. Made for our motors and wheels specifically. Made from 0.5" 

Wheels

Wheel diameter - 14", rim diameter - 6"m flat-proof tire

Link: http://www.robotmarketplace.com/products/NPC-PT5306.html

Motor Speed Controllers

6-30V, 60A

Link: http://www.robotmarketplace.com/products/IFI-V883.html

Speed controllers are needed to control motor speed and direction. They are controlled by PWM signal generated by microcontroller.

Microcontroller

32bit ARM STM32F103RB Processor, 72Mhz clock speed, 39 digital input/outputs and 16 analog inputs. Programmable with Arduino compatible Programming Environment.

Link: http://www.robotshop.com/world/leaflabs-maple-32-bit-arduino-compatible-microcontroller-1.html

Microcontroller is our Segway's brain. All sensors and speed controllers are connected to it and built in software (developed by us) will make a vehicle to balance and move.

Sensors:

Accelerometer

Link: http://www.robotshop.com/world/dimension-engineering-de-accm3d.html

We will use two accelerometers: one for forward-reverse tilt detection, brains will command motors with respective acceleration forward or reverse; and other - for steering stick tilt (left/right) detection, which will give motors a command to change acceleration speeds respectively to the desired turn.

Gyroscope

Link: http://www.robotshop.com/world/sfe-gyro-breakout-board-adxrs614-1.html

Gyro is used to detect forward/reverse angular acceleration of the vehicle. This will hep to sense inertia and prevent vehicle not to drift forward-reverse.

Voltage Sensors

Link: http://www.robotshop.com/phidgets-precision-volt-sensor.html

Each of our motors have separate batteries. During the operation motors often work on different speeds (e.g. on turns), which causes batteries to be discharged on different levels. This can cause improper movements, when driving strait forward, as motors will have different speeds supplied by different voltages. These sensors will give additional information to the software to balance "voltage difference" of batteries.

Powering:

Batteries

For motors we will use battery packs made from a123 LiFePo4 26650 cells in 8 Serial/4Parallel configuration

Link: http://www.osnpower.com/productID/product_detail-9005972_26650.html

For microcontroller, sensors and speed controller PWM power we will use 3S2P configuration pack from  LiFePo4 26650 cells

Link: http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10310

3,3V and 5V Voltage Regulator

Link: http://www.cutedigi.com/product_info.php?cPath=289&products_id=4263

This voltage regulator will power our accelerometers with 3.3V, gyro and PWM with 5V. It will powered up from 3S2P battery pack.

Next post will about mechanical parts..

[Segway] Start

Commercial Segway is very spectacular, convenient and fun vehicle. Seeing it, everybody want to try, after tying - to to have. Those who can afford it and have a need - have it, those who can not, sometimes satisfying their demand by renting :) So we decided to build our own "segway".

It's possible to virtually "take apart" this vehicle on known parts, means it's possible to build similar. Google gives many DIY projects on search words "DIY segway". There are some notable projects, like MIT's segway project. also Trevor Blackwel's Balancing Scooter. Although these projects are already old, still looking through them it's possible to define main ideas and parts and sources for the project. Also at the beginning we rented an original Segway to see how they behave. For 3 hour we tortured a poor Segway to define shapes, sizes and some basic behavior of our DIY Segway.

Brain Ring

As I remember, Brain Ring is a name of game invented in Russia (during Soviet time). This is a trivia style game, with two player teams and a person who asks questions and sets the answering time. Each team has to answer to the question by pushing a button (which flashs the light) faster than another team.
We have been asked to help a bunch of dudes, playing Brain Ring here, in Tbilisi. They wanted this automated time setter/flashing/button system.  We made it in two days using Arduino, red, green and yellow LED strips. Here is some video on this project:

Self-balancing Personal Transporter (Segway Project)

We named a project "Segway", as we are making a Segway-like personal transporter. What is self-balancing personal transporter? This is one manned electric motor vehicle, that automatically balances itself not to fall. Likewise bicycle can also be called a personal transporter and also operates by means of balancing however in this case by human.

It's a pretty interesting software challenge, to achieve balancing. There are many projects addressing this challenge - robots, transporters, and flying models made by students and enthusiasts. One of the most recognizable commercial product is Segway.

The principal idea of balancing is coming from human's ability to balance, for example - if you are standing, with your both feet put together and somebody unexpectedly pushes you from the back, you will step your leg forward in order to avoid falling and maintain your vertical (balanced position). Another example is, when you are trying to hold a stick vertically on you palm: wherever a stick leans to, you are moving the bottom edge to the same direction to bring it back to the vertical position. This is like Segway is behaving: if you lean the machine forward, it "thinks" it's falling and "makes a step forward" - it turns motors forward and brings itself back to balanced position. Same is when leaning backwards – it turns motors backwards. Unlike human, Segway needs only to react on forward-backward leaning. As a result if we want to move Segway forward, we constantly lean forward (not letting it to bring itself vertical) and as it "thinks" it's falling forward, it turns motors forward and keeps so, like a donkey running to a carrot hanged in front of him.