48 SERVO 09.2013
A second omniwheel robot was also built using the
recently released VEX IQ system. This system is similar to
the VEX Robotics Design System except in plastic. This
system comes with a selection of 30, 45, 60, and 90
degree connectors. The octagonal base was easily
constructed from stock parts.
The construction process was much faster. There are no
nuts and bolts; the plastic beams are quickly joined
together with plastic pins that snap into both beams.
The wiring was also simpler. Motors connect to the
brain with cables containing a modified style of the jacks
used with telephones. The rechargeable battery slides into
the base of the brain.
The VEX IQ motors are really neat. They have
integrated high resolution encoders (960 counts per wheel
revolution). An embedded CPU in the motor is used to
provide precise speed and position control of the motor.
This CPU uses feedback from the motor to precisely
regulate the motor’s speed. Our simple application here
didn’t need this functionality, but it will be used in an
upcoming article covering dead-reckoning navigation.