Embedded Motion Control 2014 Group 9

Team members

Name	E-mail	Student #	Remark
Koos Elferink	k.elferink@student.tue.nl	0716494
Joost Potma	j.potma@student.tue.nl	0864146
Jasper Spanjaards	j.j.a.spanjaards@student.tue.nl	0746039
Jordi van Dijk	j.v.dijk@student.tue.nl	0805981
René Bruintjes	r.f.bruintjes@student.tue.nl	0877139

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Planning

Week 1

• Installing Ubuntu
• Installing ROS
• Installing SVN
• Follow tutorial C++

Week 2

• Install Qt-creator (IDE)
• Group meeting to make a start on the project
• Test robot with standard script
• Test robot with added self made script parts

Week 3

• Group meeting (goal: finish corridor script)
• Second test on robot (test script)
• Corridor contest (16 May)

Week 4

• Group meeting (goal: maze solving strategy)
• Function to make Pico drive straight through the maze. (Koos)
• Make proper software architecture with nodes/topics (Joost/René)
• Start writing arrow detection algorithm (Jordi/Jasper)
• Measure laser distances during pico test

Future

• 20 June: Maze contest

progress week 2

-progress and format was discussed. Tasks were divided. For the corridor competition we need a set of four functions, all with input the laser data,(first increment starts at the left), output and type given, extra output possible for future extensions (as separate function)

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Corridor detection: CL, CR (type bool) true if a corridor is at ~90deg left/right of pico. Laserpoints on left and right are scanned and when value becomes large, this implies corridor. -> Jordi

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Driving: Vx, Vy, Vz (etc) -> straight, safe, and aligned driving. Also steering towards corners/endstops -> Koos

Result: library implemented, have not been able to test yet. 2 function created for area reconnaissance. One for translating laser data into coordinates, another to relate that data to straight driving objective of pico

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Corner: Vx, Vy, Vz (etc), override -> action when CL or CR is true, overrides driving function -> Rene

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end: Vx, Vy, Vz (etc), exit -> for stopping after finish -> Jasper

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Combining in main() -> Joost

progress week 3

The code written for the corridor competition was written and tested. Even though the code functioned very well in the simulator, it did not function on the real pico. Corridors on the left were taken without problems but right corners were ignored. Pico detected the right corridors well, and also took the decision to turn right. However the right turn command was not executed properly. After reordering the code, the right turns were taken fine.

Simple parallel wall driving

A simple way is implemented to drive parallel next to the wall.

The distance to the wall is measured in at an angle of 45deg left (a) and right (b). If the distance become below a threshold than pico will rotate in opposite direction as long as there is the wall (or other obstacle) within it's range.

Simple corner (corridor) detect

A simple corner (corridor) detect is impmlemented in a seperate function. On the left and right side side corridors are detected by scanning an angle of -95 -> -85 and 85 -> 95 of pico. If 95% or more laserdata points within a range is higher than a treashold, than a corridor is detected. A detected corridor, left and/or right, is send a boolean the the navigation script as a return value.

Script overview for corridor contest

to be done

progress week 4

This week we started with designing the proper framework for the different Ros Nodes and Ros Messages. Each node has a specific function and a predefined interface.

Nodes

As shown as ellipses in the figure above, the framework consists of several Ros nodes. Some of these nodes are already implemented in Pico such as the laser node and the camera node. The other nodes are described below.

Dead end

The Dead end node looks in three directions (left, right and front), to determine if one of these directions is a dead end. This information is send to the navigation node so that it won't drive in to a corridor with a dead end.

Corridor

The Corridor node looks in three directions to see if there is a corridor to drive in to. It will signal the navigation node at the point that Pico is in the middle of a corridor so that a 90 degree turn is sufficient.

Arrow

The Arrow node processes the camera date to look for an arrow in the image, and if there is an arrow, in which direction it is turing. This information is also send to the navigation node.

Navigation

The Navigation node determine the direction in which to drive to. To make a decision based on the data from the Dead end, Corridor, and Arrow node. It is a rule based navigation based on the principal to always go left. In this case the exit of the maze is always found. If there is a possibility to go left it always will go left unless it is overruled by a right pointing arrow. If it can go straight and right it will always go straight. If the only option is right it will go right. And if all the three directions are a dead end if will turn 180 degrees.

Drive

The Drive node will execute the commands given by the Navigation node. The default option is to drive straight unless there is a command to make a turn.

scanxy and straightdetect

For the detection of the world and the desired direction, two scripts have been implemented. These two are visualised in the figure.

Scanxy; (purple lines)

This function reviews the laserdata and tranlates them to a structure with their x and y distance with respect to pico.

Straightdetect; (other lines)

This function uses the result of scanxy, a struct of type Sxy of x and y coordinates. It analyzes the direction of the corridor with respect to the orientation of pico. It does this by looking at 2 laser points and comparing the dx and dy to calculate an angle. For robustness this process is repeated for multiple pairs of dots, the results are filtered and averaged. This results in a good and robust measurement of the angle which pico could rotate to be located straight in the corridor.

=> updated version: linedetect;

input: (Sxy xy,double x1, double x2, double y1, double y2, double angle, double Tol) Here the square where the function searched within is defined bij x1<x<x2 and y1<y<y2, by the user, and so is the desired search angle with certain tolerance angle.

Middledetect;

Middledetect uses the structure Sxy xy to determine the middle of the hallway. It returns the distance in which it could drive to find the middle of the corridor, but does not steer of the wall for more than 0.75m