Content Comparison

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Design	Generated MAP (Isometric View)	Example of GML file

4. Path Planning

5. Simulation and Results

Mobile Platform Model (used in the simulation)

Generalized Coordinates
where:
x and y are the two coordinates of the origin P of the moving frame θ is the orientation angle of the mobile robot is the rotation angle of the right driving wheel is the rotation angle of the left driving wheel The vehicle velocity v can be found in equation in the equation: is the angular velocity of the right wheel is the angular velocity of the left wheel

Kinematic Constraints

Algorithm

A* Algorithm	Time Enhanced A* Algorithm
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5. Simulation and Results

Simulation Using

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VREP

	Multimedia name sim_vrep_01.mp4

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Analysis

• Temporal Analysis
  
  Test 1: Example of an overtaking. Two robots, 1 and 2, follow in the same direction with the same speed. Vehicle 2 overtakes the vehicle 1.

  Test2: Example of two paths without intersections.

  Test3: Example of the intersection of two Robots, followed by the passage and overtake of vehicle 2 by the vehicle 1.

  
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• The implemented algorithms handles these problems in different ways. The Time enhanced A* Algorithm considers path planning and coordination simultaneously.
• The path of each vehicle is calculated according to the paths of the other vehicles. In this sense, the coordination between robots is ensured.
• The vehicles’ path is restricted to the predefined segments, while the Time enhanced A* gives the vehicle the flexibility to navigate in all free cells.
• Considering that the Time enhanced A* Algorithm includes time and movements of the other vehicles on their paths’ calculation, overtaking is allowed.
• It’s possible to conclude that the Time enhanced A* Algorithm is more flexible in the generation of paths, because the calculated paths can be adjusted according to their cost, obstacles and the other Robot movements

References

1 U.S. Government. National Space-Based Positioning, Navigation, and Timing Coordination Office’s GPS information, 2010.

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5 OpenStreetMap. OpenStreetMap, 2010.

6 DuToit, N. (2010). Robotic Motion Planning in Dynamic, Cluttered, Uncertain Environments. In Proceedings of the IEEE International Conference on Robotics and Automation (ICRA)

7  Knepper, R. A. and Kelly, A. (2006). High Performance State Lattice Planning Using Heuristic Look-Up Tables. In Proceedings of the IEEE-RSJ International Conference on Intelligent Robots and Systems (IROS)