The design of the autonomous golf cart is a
multi-year endeavor. In order to provide a platform
for further development, a 2005 Yamaha G22E golf cart
needed to be modified to be controlled remotely. To
do so the vehicle required heavy modification of the
steering and braking systems as well as electrical
integration with the on-board controller. With these
modifications multiple safety mechanisms had to be
added to the golf cart to protect the passengers and
those in the near vicinity.
In order to properly steer the golf cart remotely, the Yamaha’s rack-and-pinion system had to be modified. Multiple solutions were presented such as using a motor and belt system, drive by wire directly connected to steering column, and a pre-built power steering system. Through feasibility analysis the pre-built power steering system was decided upon. The power steering system was donated by Wicked Bilt and consists of a torque sensor and motor.
In order to install the Wicked device a mounting bracket had to be designed and installed. Additionally the steering column had to be shortened and a spline provided by Wicked was used to interface with the Yamaha rack and pinion steering. To sense the position of the steering column a multi-turn potentiometer was determined to be the most economical option. A multi-turn encoder was considered but rejected due to cost. To mount the potentiometer a small l-bracket was used.
The braking system of the golf cart also had to be
modified, however not as significantly as the
steering. To implement remote braking an actuator was
used to pull a steel cable that was connected to the
brake petal. Due to the size of the actuator it
required a pulley to make a 90° turn before
connecting to the brake petal.
The actuator and the pulley were mounted to the golf cart frame. This method allows for the passenger in the driver’s seat to still be able to hit the brake in an emergency situation. For feedback the internal potentiometer of the actuator was used as well as a magnetic field sensor.