This small 8 inch circular
      robot will be the test bed for experimenting with indoor navigation,
      starting with wheel encoders. From there, more sophisticated
      sensors will be added to allow the robot to place itself in its
      environment accurately, and perform simple house hold tasks using
      this new capability.

 
 This update shows the big
      changes Ive made in the past two months to the Navbot which is
      now close to attempting its first primary task of navigation
      the entire length of the house from a pre determined starting
      and ending points. Here Ive added the new frontal sonar sensor,
      and second the magnetic compass sensor on a mast forming the
      beginnings of a "head" for the robot.

CLICK ON THUMBNAILS FOR A 1024 X 768 VIEW
 
 Shown
      here is a frontal view with the sonar unit on the bottom of the
      bumper pointing forward to measure distances to targets and non
      contact obstacle avoidance. It will be primarily used to home
      in on the target positions. The compass, a Devantech CMPS03 provides
      PWM outputs to indicate 0 - 359 degrees forward direction. It
      was adapted from the Geobot, and a full write up on its function
      and mathematics I used for its operation can be found there.
      This magnetometer is mounted on a wooden non ferrous pole to
      space it from the robots motor drives and no metal screws are
      used in the head unit.

 

      
Movie
      1
Left: this small mpg movie shows the robot
      moving in a straight line within the house hold environment.
      The robot takes an initial bearing upon turn on and follows it
      until it reaches within 1 foot of the distant wall. The robot
      would be easily several feet off if it had not used the compass
      from the slippage on the floor and differential wheel speed.


 

      
Here are the past updates on the robots progress:
Update 3/11/11       New hall effect magnetic stasis sensor
Update 2/27/11      New Wheel Encoder Sensor
Update 1/2/11         First stab at a home made wheel encoder
Update 12/27/10    Removal of servo motors with standard DC gear motors
Update 11/25/10     First try with servo motors was not good


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