  This study presents the design of a six-wheeled outdoor autonomous mobile
robot. The main design goal of our robot is to increase its adaptability and
flexibility when moving outdoors. This six-wheeled robot platform was equipped
with some sensors, such as a global positioning system (GPS), high definition
(HD) webcam, light detection and ranging (LiDAR), and rotary encoders. A
personal mobile computer and 86Duino ONE microcontroller were used as the
algorithm computing platform. In terms of control, the lateral offset and head
angle offset of the robot were calculated using a differential GPS or a camera
to detect structured and unstructured road boundaries. The lateral offset and
head angle offset were fed to a fuzzy controller. The control input was
designed by Q-learning of the differential speed between the left and right
wheels. This made the robot track a reference route so that it could stay in
its own lane. 2D LiDAR was also used to measure the relative distance from the
front obstacle. The robot would immediately stop to avoid a collision when the
distance between the robot and obstacle was less than a specific safety
distance. A custom-designed rocker arm gave the robot the ability to climb a
low step. Body balance could be maintained by controlling the angle of the
rocker arm when the robot changed its pose. The autonomous mobile robot has
been used for delivery service on our campus road by integrating the above
system functionality.
