where vxG is the velocity in the direction of xG, vyG is the
velocity in the direction of yG. ωL and ωR are the rotational
speeds of the left and right wheels. The angular velocity of the
robot according to the earth coordinates is equal to u as shown
in (2).
The wheeled base of the robot has five locomotion behaviors:
go forward, go backward, turn left, turn right, and stop. The
moving direction of the robot is decided by the velocities of
the left and right wheels. The rotation velocity of the DC
motors can be controlled by using the PWM (pulse width
modulation) technology