Sample Robot #1-B

• Summary:
• Modified from Sample Robot #1 design.
• same: Large drive wheels on center axis, under RCX body.
• same: Motors behind RCX body drive each wheel via a medium gear pressed against the tire!
• changed: Rearidler wheel (without tire) on center line.  [front wheel removed]
• changed: Front facing ball arm, with a flipping motion, directly connected to a motor axle.
• Light sensor at rear, facing down.
• Rotation sensor connected to the right wheel axle (turned via a small drive belt).
• Touch sensor at front, facing forward, with a wide push bar attached.
• Good features:
• Good traction on smooth or carpet surfaces.
• Medium fast motion.
• Works forward and backwards.
• Excellent turning ability (can turn in place).
• Wheel drive is simple and reliable on flat surfaces (direct "rim" drive).
• Ball arm is simple and reliable (direct drive, no gears or belts).
• Light sensor can detect black floor line, to determine when to turn left (or for other uses).
• Rotation sensor can record distances for navigation / backtracking.
• Touch sensor can detect when container is reached, to activate the ball arm.
• Small compact design.
• The redesigned ball arm can deposit the ball a few inches or more from the robot, adjustable via motor power.
• It is almost always successful at dropping a ball in a properly positioned container (mission 2).
• Not so good features:
• Sometimes this robot does not go very straight.  It originally tended to pull to the left, especially going backwards.
• By adjusting the wheels, which apparently were rubbing, this problem was greatly reduced.
• Forward facing ball arm requires the robot to turn for mission 2.
• Could be redesigned to face the side.
• Using sensors makes the programming more complex (but more reliable).
• Distance travelled might depend on battery condition, surface, etc.
• Moderate to poor climbing ability, caused by drive gear slippage.
• Sometimes the turns (controlled by timing) are slightly more or less than 90 degrees, causing the robot to go off course.
• Note: using the rotation sensor for controlling turns seems even less accurate, due to the small number of rotations.
• Some parts of the robot are not strongly attached.  Parts may fall off if bumped hard.