Embedded Motion Control 2014/Goal

The goal of the assignment is to get the real-time concepts in embedded software design operational.

The concrete task that has to be solved is to let the PICO robot find his way out of a maze. The final demonstration by each participating group of 4-5 students will be performed during a contest, the winner of which is the group that exits the maze in the shortest amount of time. To prepare for this competition the following guidelines have to be considered:

• to test with PICO and to prepare for the final contest, a simulator will be made available that mimics the in and outputs to the real robot. Specifics of this simulator will be presented in the first lecture on September 4th
• the maze of the final competition will be constructed just before the competition. The maze presented in the simulator is therefore different from the real one used in the final contest.
• both on the real and simulated PICO robot, three sources of sensor information will be available to perceive the environment and to derive the state of the robot:
  • laserdata provided by the forward pointing laser scanner,
  • images captured by the monocular camera,
  • odometry provided by the base controller
• the robot can be actuated by sending information to the base controller
• during the final contest, it is highly imperative that the PICO robot refrains from colliding with the walls in the maze. Colliding with the walls will result in severe time-penalties.
• the walls of the maze will contain several types of pointers to the exit, which can potentially help PICO to speed up execution of the task Click here for a pdf file containing the arrow we will use. We also captured PICO's camera topics in a bag file while the robot was looking at the arrow. You can play this bag-file as follows:

  rosbag play 2013-10-08-15-35-04.bag

  The topics /pico/camera and /pico/camera_info should then become available. For example, while playing the bag file, use

  rosrun image_view image_view image:=/pico/asusxtion/rgb/image_color

  to view the camera images. If your laptop becomes to slow to handle the stream of images, you can also play the bag-file at a lower rate. For example, use

  rosbag play 2013-10-08-15-35-04.bag -r 0.5

  to play it at half the recorded speed.

Corridor Competition

An intermediate review will be held on May 16th, 13.45h at the RoboCup soccer field. During this challenge, called the corridor competition the students have to let the robot drive through a corridor and then take the first exit. The precise location of this exit will not be given in advance. Some facts:

The exit can be either left or right It is not known beforehand how far the exit is located from the start (somewhere between 1 and 10 meters) It is not known beforehand if the opposing end wall (on the far end) will be open or closed The walls are approximately parallel to each other Note: the walls might not be perfectly straight The distance between the walls is not known in advance, but will be reasonable (somewhere between 0.5 and 1.5 meters). The distance between the walls will be fairly constant throughout the corridor, 'fairly' meaning that we build the corridor by hand, and the distance may change a little along the corridor. PICO will start with its laser range finder between the walls PICO will be approximately facing the end of the corridor. (Notice: approximately, so don't just drive forward for n seconds!) At the exit, the finish line is located approximately 30 cm from the side of the corridor (Notice: approximately, so don't just drive forward for 30 cm!). The walls that can be used to align PICO will be a little bit longer. You have finished the assignment if PICO did not drive into walls, took the correct turn and the entire rear wheel is across the finish line. Hitting the wall will result in 0 points!

Maze Competition

The final competition will be held on June 27th, 13.45h at the RoboCup soccer field. The goal of this competition is to let PICO autonomously drive through a maze and find the exit. Some facts:

• Where and when:
  • Fri June 27, 13.45h - 15.30h
  • Location: RoboCup Soccer field, GEM-N
• Maze characteristics:
  • Exact location of the entrance and exit are unknown, but they will be on the boundaries of the maze
  • walls are approximately parallel to each other
  • distance between walls is approximately constant throughout the maze, and large enough for the robot to perform complete rotation without hitting the walls
  • There may be corners, T-junctions and crossings (+)
  • There will NOT be any loops in the maze
• Arrows:
  • On some T-junctions there is an arrow pointing to the side that leads to the exit (either left or right, and the arrow will never point in wrong direction)
  • Arrows are located on the highest point of the wall, i.e., clearly visible for the camera
• Start, goal and limits:
  • PICO will start with its laser range finder within the boundaries of the maze
  • You have finished the assignment if PICO did not drive into walls, found the exit and the entire rear wheel is across the finish line.
  • There will be a maximum translational velocity of 0.2 m/s (X and Y combined!) and maximum rotational velocity of 1.0 rad/s
• Scoring:
  • You have 2 attempts (= maximum one restart)
  • restart means:
    • PICO restarts at beginning of maze
    • MAZE time (= time used for scoring) is reset, BUT
    • TOTAL time keeps running
  • You have a total of 7 minutes for both attempts
  • Hit wall = that attempt fails
  • PICO standing still for 30 seconds = that attempt fails
  • No second attempt if first attempt was successful