Embedded Motion Control 2014 Group 10

Members of group 10

Bas Houben	0651942
Marouschka Majoor	0660462
Eric de Mooij	0734166
Nico de Mooij	0716343

Planning

Week 1

• Introduction
• Install Ubuntu

Week 2

• Determine the course goals
• Brainstorm about the robot control architecture
• Start with the tutorials

Week 3

• Continue with the tutorials
• Install ROS/QT
• Finish robot control architecture
• Brainstorm about collision principle
• Brainstorm about navigation

Week 4

• Meet with the tutor
• Finish installation
• Finish tutorials
• Write collision detection
• Write corridor navigation
• Test the written code on Pico
• Corridor challenge (Recorded performance)

Concepts

Robot program architecture

The idea of our architecture is to create different process layers. By splitting the incoming signals and combining them later, the tasks can be divided and the different processes can run in parallel. Layers are based on the available sensors as much as possible.

Wall detector

The wall detector determines whether the robot is close to a wall or not by determining the unblocked distances at its two sides. When either side is too close (within 30cm) it turns parallel to that side, taking a distance of 30cm from the wall.

Intersection detection

When driving forward, Pico uses the measured distances at different angles from the laser data in order to detect corridors. These distances are visualized in the figure on the left. The red circle part covers 72 degree with a radius of 0.5m, the green circle part covers 35 degree with a radius of 1.0m and the blue circle part covers 25 degree and a distance of 1.5m. The circle part tips outside of pico are on two parallel lines 60cm apart. When each of this circle parts doesn't detect any obstacles inside, this is considered to be the corridor.

All holes smaller than 0.30m will never be detected as corridor because the slimmest part of the laser range bundle outside pico is 0.30m. (Just outside the part covered by the red circle part, inside the blue circle part). The smallest hole that always will be determined as corridor is 0.60m; the laser covers a with of 0.6m. Holes within 0.30m and 0.60m might be determined as corridor, dependent on the length of the exit and pico's positioning. |}
Intersection determination

Depending on the results from the intersection detection part, Pico will determine which situation he is in. In the maze, these situations could be 4-way intersection, corners and T-junctions. The image below shows how each situation is determined depending on the presence of a wall or corridor in the forward, left or right detectors. At this point, arrows can not yet be detected, so that part of the protocol is skipped. Once arrow recognition is implemented, the arrows will be used to determine the correct corridor to take at T-junctions, or to move towards a T-junction at the end of a corridor, if an arrow is detected in the distance.

Moving through intersections and corners

Once Pico has detected a situation and determined if he want to turn, he will rotate + or - 90 degrees. After the rotation, Pico will drive forward a small distance to position himself fully into the next corridor and will look around once more.