Transcript GPS Guided Autonomous Vehicle Navigational System

GPS Guided Autonomous Vehicle Navigational System
Startup
Authors:
Navik Agrawal
Greg Kuperman
Bashar Saleh
Straight Path Navigation
Maintain Straight Line
End
Point
Advisors:
Mr. Phil Farnum
Mr. Sid Deliwala
Perpendicular Boundary Lines
Because of the innate inaccuracy of GPS, the vehicle cannot move from a
start point to end point in a perfectly straight line. Each subsequent GPS
reading has the potential of varying from the previous reading by up to 3
meters. To remedy this problem, the system waits till the machine is
moving at operating speed. At this speed, the heading angle with respect to
north is computed and is compared to the angle of the intended path with
respect to north. Based on slight deviations (shown in brown), the vehicle
turns left or right.
ABSTRACT
Deviation from
Path
The lawnmower is a vehicle that naturally lends itself for a GPS
application. One can assume, quite realistically, that a lawnmower will
operate outdoors in a large open field. Such an area is an ideal location
for GPS to function at its best. The question remains whether or not
the accuracy of GPS, which is up to three meters 95% of the time,
would allow GPS to successfully navigate a lawnmower.
Results indicate that the non error corrected GPS measurements
will be able to navigate an RC vehicle with a decent degree of accuracy.
The average deviation from the path is approximately one meter. The
navigational system is implemented on an RC vehicle (TXT-1) obtained
form the GRASP Laboratory from the University of Pennsylvania.
Eventually, the navigational system will be adapted to a full scale
lawnmower in a future senior design project.
Demonstration:
April 21st, Thursday
9:00 am, 1:00 pm, 1:30 pm, 2:00 pm
Start point
Vehicle Trajectory
Continue along
Path
Initial Path-finding Algorithm
With this algorithm, the vehicle can be placed in any direction within the boundaries. With
the four corners of the region, four perpendicular boundary lines (shown in teal) are created. Once
the car accelerates to operating speed, the system obtains the heading of the vehicle with respect to
north and the GPS coordinates. With these two values, the vehicle’s projected trajectory (shown in
brown) can be computed. Then, the system computes the intersections of the projected trajectory
and perpendicular boundary lines (shown in red). From these intersections, the system determines
which intersection points are in the direction of movement and which point is closest. Once the
vehicle arrives at the closest intersection point, the vehicle will turn onto the path. Thus, the
system can put the vehicle onto the correct path regardless of the starting conditions.
University of Pennsylvania, Department of Electrical and Systems Engineering
Complete Traversing Entire Region