Final Report Alpha Squad Seven

1
Final ReportAlpha Squad Seven

• Members
• Erik Bass
• Benjamin Carter
• Rahul Kapoor
• Steven Koegler
• Jared Schlicher
• Matthew Werner
• Coach
• Alex Hsieh
• Date
• 3/15/07

2
Software Architecture
3
Camera

• Controlling used ptzProxy()
• Creating Image

captureframe undefined jpeg Headerfile not accessible
cameraproxy undefined jpeg
framgrabber Undefined inbuilt function Downloaded header not compiling
4
Point Translation and Boundaries

• Use Direction and Robot relative points to find
  global points
• Robot relative points come from the lidar
• Robot direction based on ?x and ?y
• Global points checked to with boundary conditions
• Boundaries are the G.P.S. coordinates of the walls

5
LIDAR Function

• ID 1 Object Avoidance
• Filters out objects out of the box
• Returns y-distance (R) of closest object
• Y-dimension is a variable
• X-dimension hardcoded at .7 m

6
LIDAR Function

• ID 2 Intersection
• Scans 180 degrees
• Translates points of objects detected
• Compare with intersection coordinates
• Wait/Go

7
Way-point Following

• The Initial Problem
• The Solution (Look-Up Table)
• The Implementation
• The Calibration

8
The Initial Problem

• The way-point program initially had problems when
  the robot was not aligned properly with the first
  way-points.
• Swerve back and forth on the ideal line from one
  way-point to the next.
• However if the robot was aligned properly to the
  first way-point, the robot could navigate the
  given seven way-points with some what of a smooth
  line.

9
The Solution

• Create a look up table based on two values the
  angle and distance to the way-point.
• The look up tables angle was incremented in units
  of fifteen degrees until it reached seventy five
  degrees.
• The distance started at 0.5 m and was incremented
  by a full meter until the distance reached 4.5 m.
• With five distance states and six angle states
  the table gives a total combination of thirty
  steering inputs.

10
The Implementation

• The look-up table was implemented in C.
• Six stacked if-else conditional statements for
  the angle check.
• Nested if-else statement for the distance check.
• With in the appropriate if-else statement the
  steering angle is assigned.

11
The Calibration

• First every steering input was set at the maximum
  steering.
• Adjusted the steering for the table by
  multiplying the maximum steering by a value from
  zero to one, basically to take a percentage of
  the maximum steering available depending on the
  state.
• Then entered a guess for each state, through
  trial and error for way-point following, tuned
  the steering.
• Applied the table to the intersection problem,
  the lane change problem, and then to object
  avoidance problem and made adjustments where they
  were needed.

12
Object Avoidance

• Use Lidar to scan for object
• When object is found check distance
• Ignore large distances
• If distance too small stop
• If distance in between then
• If link has 1 lane then stop
• If link has 2 lanes then switch lanes

13
Lane Switch Logic

• Find current lane position
• Create line based on opposite lane points
• Found using two closest opposite lane points
• Once line is found create a new waypoint in the
  other lane.
• Once past the object switch back into original
  lane.

14
Intersection Problem

• How to determine if we are at an intersection
• How to determine if there is a stop sign for the
  intersection

15
Reading the Network File

• The Intersection Problem is solved by reading the
  Network File
• The Network file contains node and stop sign
  information
• The code reads this information to determine if
  the robot is at the end of a link
• Then the code determines if there is a node at
  the end of the link the robot is located at
• Finally, the code determines if the node contains
  a stop sign

16
Navigating an Intersection

• If stop sign, then stop for set time
• During stop use lidar data to determine if an
  object is within defined intersection
• If object is, pause for more time than initial
  stop
• If object is not, proceed after initial pause
• If node has no stop sign, continue driving

17
Conclusion

• Control Issues
• Point Translation and Boundary Conditions
• Driving Control
• LiDAR Function
• Obstacle Avoidance
• Intersection Navigation

18
Questions