Rocky 2

born about January 2009

Rocky 2 (still known as "Rocky" for short) is my second robot in this family.  After almost five years of work on my original Rocky,  I wanted to try a new mechanical design.  Mostly, I wanted a robot with more stability.  Ever since I moved my new and heavy laptop to Rocky's top, he just wasn't as stable as I wanted.  You can tell by the pictures of Rocky that the laptop used to be mounted much lower.  The robot ran fine that way.  But when I bought a new HP laptop, the screen would not open up to 180 degrees like my old Dell, so I had to move the laptop up. Anyway, Rocky had fallen a few times and I wanted a robot that would be almost impossible to tip over.  This robot design is loosely based on the Stanford S.T.A.I.R robot.

Rocky 2 seems to meet that requirement.  While he is as tall as Rocky 1, the weight is mounted lower with only a few relatively light sensors mounted high up. Also, the drive wheels and casters are located to give much more stability even though the robot is still 18 inches wide, same as Rocky 1.

Of course, the benefits of a circular differential drive base are now gone.  Rocky 2 can't pivot around within his own radius.  Hence, navigation around walls and obstacles is going to take a lot more intelligence.  But, I'm trying to build more intelligent robots, so this is a logical next step.

Features of the new Rocky include:

    New drive motors which direct mount to 10 inch wheels for a top speed of about 500 mm/sec.  And tons of torque.

    Using RC based motor drivers rather than direct H-bridge.  Both modes are supported by the microcontroller board.

    Finally added some bumpers that I'm almost happy with.

    Hmmm, and since it may not be obvious, the drive wheels are on the BACK.

    Added a new I/O board (SD84 Servo Control Module, available from  It has 84 I/O ports which can each control an RC servo or be a discrete input port (1 bit), or a discrete output port, or 36 of the ports can be used for analog inputs.  This board is controlled by USB directly from the laptop.  This will free up the 7 RCservo/Sonar ports on the microcontroller to be used for up to 7 sonars.

    The sensor complement is pretty much the same as Rocky 1.
        URG04 Laser scanner
        USB microphone
        CMPS03 compass
        Rumblepad wireless Game Controller receiver  (soon to be implemented in next Nav & Control distribution).
        And the usual sensors supported by the micro board:  IR range, sonar, etc.  Which I haven't installed yet.

    You may notice that the laptop screen points backwards, hence I can't use it for an animated face as I did on Rocky 1.  Rocky 2 is going to have an animated character (like the Elmo Live) sitting on the front between the speakers.  He'll have his hands on two control sticks so that it looks as if he is driving the robot around.

All the following photos are thumbnails and you can click to enlarge them.

rocky2.jpg (124107 bytes)Rocky2front1.JPG (81027 bytes)Rocky2back.JPG (70707 bytes)Rocky2left.JPG (79891 bytes)Rocky2rtside.JPG (137954 bytes)Rocky2bot.JPG (129718 bytes)