Embedded Motion Control 2013 Group 3

Contact info

Vissers, Yorrick	0619897	y.vissers@student.tue.nl
Wanders, Matthijs	0620608	m.wanders@student.tue.nl
Gruntjens, Koen	0760934	k.g.j.gruntjens@student.tue.nl
Bouazzaoui, Hicham	0831797	h.e.bouazzaoui@student.tue.nl
Zhu ,Yifan	0828010	y.zhu@student.tue.nl

Meeting hours

Mondays 11:00 --> 17:00
Wednesdays 8:45 --> 10:30

Meet with tutor: Mondays at 14:00

Planning

Ma 09 sept:

• Finish installation of everything
• Go through ROS (beginner) and C++ manual

Wo 11 sept:

• Finish ROS, C++ manuals
• Start thinking about function architecture

Ma 16 sept:

• Design architecture
• Functionality division
• Divide programming tasks

Do 19 sept:

• Finish "state stop" (Koen)
• Finish "drive_parallel" (Matthijs, Yorrick)
• Creating a new "maze/corridor" in Gazebo (Yifan)
• Simulate and build the total code using Gazebo (Hicham)
• Testing with robot at 13:00-14:00

Vr 20 sept:

• Finish "crash_avoidance"
• Coding "gap_detection" (Yifan)
• Coding "dead_end_detection" (Matthijs, Yorrick)
• Coding "maze_finished" (Koen, Hicham)

Ma 23 sept:

• Finish "drive_parallel"
• Putting things together
• Testing with robot at 12:00-13:00 (Failed due to network down)

Unfortunately we encountered some major problems with the Pico robot due to a failing network. We discussed the approach for the corridor competition. At this point the robot is able to drive parallel through the corridor and can look for gaps either left or right. We a gap is reached the robot will make a smooth circle through the gap. This is all tested and simulated. For the corridor competition we will not check for death ends. There isn't enough time to implement this function before Wednesday 25 September. The corresponding actions such as "turn around" won't be finished either. Without these functions we should be alble to pass the corridor competition successfully.

Di 24 sept:

• Testing with robot at 13:00-14:00
• Finding proper parameters for each condition and state

Wo 25 sept:

• Finish clean_rotation
• Finish gap_handling
• Putting things together
• Corridor Challenge

PICO usefull info

• minimal angle = 2,35739
• maximal angle = -2,35739
• angle increment = 0,00436554
• scan.range.size() = 1081

Strategy

For navigating through the maze we use a "wall follower" strategy. This means that the robot will always stick to the right wall and always find it's way to the exit. At a later stage we will extend this base strategy with extra features such as the camera to detect instructions. The main robot controller can be in six states according to the conditions. The conditions are:

• Dead_end_detection
  • Input(s): (sensor_msg) LaserScan_data
  • Output(s): (Bool) dead_end_detect
  • The flag "dead_end_detect" is set when the robot measures a death end in front.
• Gap_detection
  • Input(s): (sensor_msg) LaserScan_data
  • Output(s): (Bool) gap_detect
  • The flag "gap_detect" is set to true when the robot is located at the center of the gap. Only gaps on the right-hand side will be noticed.
• Crash_avoidance
  • Input(s): (sensor_msg) LaserScan_data
  • Output(s): (Bool) chrash_detect
  • The flag "chrash_detect" is set when the robot measures an object closer then 30 centimeters over the entire laser range.
• Maze_finished
  • Input(s): (sensor_msg) LaserScan_data
  • Output(s): (Bool) finalize
  • This flag will be set to true when the robot exits the maze and detect no object closer then 2 meters around it.

Within these functions a flag is set when the robot is in a certain condition. All based on the data of the laser scanner. Based on the flag which is set the robot encounters a certain condition and will be in the corresponding state. The six states are:

• state_drive_parallel: Keep the robot at a fixed distance (setpoint) from the right wall while driving.
• state_gap_handling: When arriving at the center of a gap (to the right). Rotate in place untill parallel with new right wall.
• state_stop: Stops the robot when necessary.
• state_finalize: When no longer between two walls and no maze in front, abort.
• state_turn_around: when at a dead end, turn around.

The state functions will be called according to the flag and determines the linear and rotational velocities. We will use one node that "spins" and subscribes to the laser data, and publishes the velocities.

The figure below depicts the simplified architecture of the program at this point.

Design approach & conventions

• datastructures.h: put all global variables and datastructures here.
• states: each contains the functionality of a state.
• conditions: each checks a certain condition to determine the next state.

• theseus is name of the package/node to execute
• theseus_controller is the controller that is iterated and runs:

   Gather conditions e.g.: crash_avoidance, gap_detection.
   Based on the information a state will be chosen and executed.
   Publish velocities.

Corridor Competition

"Theseus corridor competition"