NINA
The Robot
Nina is a large scale robotics project I undertook around 2003. As a young child, I always dreamed of building my own robot. As I grew older, I eventually forgot my obsession with robots and moved onto other interests.
However, toward late high school it suddenly struck me...
"Hey...I could read books about how to build robots and build my own robot!"
So I headed on over to the library to check out some books on robotics, electronics, computers, mechanics and other things. I knew it was going to be long process and a journey in itself to learn. But I like challenges, and I the journey was a fun part. After months and months of reading I designed a simple project and...well, okay I could read, but I didn't have any experience. I bought a few things at a local surplus store but the project never came close to working out.
I then decided to fiddle around with a VEX robotics kit, which I was given as a graduation present. The VEX robotics kit comes with mechanical building materials, electronics and microcontroller (the computer part the robot), sensors and fasteners. The rest is up to your imagination. I built two robots with the VEX kit: the first being a quadruped and got around fairly nicely. The legs were a little wobbly on this robot, however, so I called it "Bambi" for fun. The next robot was a rover (a wheeled robot) with a rudimentary mechanical arm. I called this robot Banzai. Both robots were remote controlled and had minimal autonomous features (meaning they couldn't really do anything on their own). After getting some experience under me, I decided it was time to move on to building a robot completely from off the self parts--what some might call building a robot from "scratch."
NINA was the robotics project I undertook. NINA's original design provided for tank-track differential drive, a monocular webcam for vision, a laptop computer for logic, one articulated arm, a load of sensors, and.....
LASERS!!!!!!
Her original function and abilities were to be able to navigate around the house by identifying landmarks with his vision system, respond to voice commands, speak via text-to-speech software, night guard the house, put out fires, detect noxious fumes, and maybe fetch soda pop from the fridge.
Why did I need a robot to do all this, you ask? Well, I didn't, but I wasn't building this robot to do everything around the house for me. I wanted to see what I could accomplish, what problems I could solve, how far I could go, and what I could achieve if I put my mind to it. So NINA's top most goal for me was to serve as an educational experience and a test of my abilities.
The NINA project has taken me about seven years to full accomplish, from study to building, programming and testing. Until finally, toward October of 2009, I had a (more or less) fully functional NINA robot. So, without further adue, I give you...(drum roll please)...NINA Version 0.7!
------ "Hello, everyone!"
NINA is still a prototype, but she's growing up, so to speak and she's come a long way.
I had NINA demonstrate for Halloween in front of the house, and fortunately that was a great success. Only a few minor bugs in her programming showed up and her batteries held out longer than I thought they would.
Mobile Base
NINA is driven by two heavy duty wheelchair motors, which out powered by two 12 Volt, 10 Amp-hour battery packs wired in parallel for longer lasting operation. The Motor Drive circuitry is a Sabertooth 2x25 differential motor driver (which is not mounted in this picture). The Sabertooth 2x25 is a heavy-duty circuit board sold by Dimension Engineering that can deliver up to 25 amps of continuous electrical power to each of two motors from a heavy duty power source (like NINA's 12 volt 20 amp hour battery pack). Her rubber tracks are 3 inches wide and are sold by Lynxmotion. The sprockets for these tracks are attached to the wheelchair motor shafts via an aluminum hub with a 5/8 of an inch wide bore. I requested these aluminum hubs as a special made item from AndyMark Inc, and they were generous enough to make it a mainstream item on their store. The frame of NINA's Mobile base is made from heavy duty steel and thick aluminum.
Some problems with the base are that the motors are too powerful and the base is too heavy. That's why I currently don't have NINA roam around the house. What I plan to do to fix that problem is mount lighter weight motors, such as these two electric bicycle motors I bought from allelectronics.com.
They weigh a little less than half the weight of the wheelchair motors and are still powerful enough to push the weight of the robot.
I also intend to replace NINA's heavy duty steel frame with moderately strong aluminum instead.
Also, NINA's original power source was a 12V 35 Amp-hour Sealed Lead Acid battery that weight about 30 pounds. The new Nickel Metal Hydride Batteries weight only about 16 pounds together, which is why I switched to them.
NINA's arm, torso, and neck "joints" are mobilized by Hitec servos and ServoCity power servos. A servo is just a motor that only turns to a certain angle and doesn't spin around round like a conventional motor, making them ideal for robot joints. The servos are powered by a 6V 10 amp hour battery pack wired to a Lynxmotion Serial Servo Controller sold by lynxmtion.
Part of upgrading NINA from version 0.7 to version 1.0 will involve the addition of sensors. NINA is already equipped with an onboard microphone for speech recognition and two webcams for stereoscopic computer vision. Additional sensors will include things like:
Ultrasonic Range Finders:
NINA will be decked with about six to eight of these round around her mobile base. These sensors detect obstacles by shooting a very small, inaudible ultrasonic noise. When the sound wave bounce off a wall or obstacle, the sensor receives it and processes it into logic through transduction. It then sends a signal to NINA's Central Sensor Board to tell the robot that an obstacle is in the way. It can also tell the robot how far away the object is through proper timing and programming.
Infrared Beam Sensors
In addition to Ultrasound, NINA will also be equipped with LASERS!!!
.......
Well, okay, this isn't exactly a laser beam, but its close. This sensor shoots a narrow beam of infrared light. When the IR light hits a wall or an object, it reflects off of it and bounces back into the sensors receptor. The sensor's circuitry then converts the light energy to logic data through transduction. The robot can also tell how far away the object is through the amount of light energy being converted in this sensor's receptor component.
This is going to be NINA's Central Sensor Board.
This board is usually used as a servo controller, but I'm using it mainly for the amount of analogue data it can read from sensors. This piece of circuitry can handle up to 84 servo motors, and it can read up to 36 channels of 10-bit analogue input from sensors.
As of now, NINA has little ability to manipulate her environment. Therefore, I'm going to mount a robotic hand (which is also called a "gripper") to her right arm.
It's a three fingered hand and simply opens and closes. It was designed by Karl Williams in his book "Build Your Own Humanoid Robots." I intend to incorporate an IR sensor in the palm of the hand so the robot can check to see if anything is in grasping range when the machine is reaching out for something. I may also add pressure sensors in the fingers.
Videos
Here's a short video of NINA version 0.1 responding to my voice commands and moving around the house.
(I apologize for the poor quality here. I'll try to upload better quality videos soon.)
Here's a video of me demonstrating NINA's Artificial Intelligence for conversation. This program
NINA will run is what I'm dubbing a "Social Machine" program. The idea is to use Robots (or computer characters) to help those with Autism or Asperger Syndrome learn to communicate with all their fellow human beings without worrying about the robot being judgemental of mistakes. It's a daunting task, but an wonderful idea I'm exploring.
(Sorry about the strange clicking in the background...I'm working on getting better videos up in time).
More videos to come soon.