June 2nd 2010Line Tracking & Mission to Mars

Embedded Motion Control

Group 1Rene ThijssenLuke LathouwersMaarten van StuijvenbergRoel ten HaveBastian Eenink

Line Tracking – Hardware DesignOverview functionality (I/O per RCX):

• Two light sensors are used to track the line• Both light sensors are positioned above the line

• Encoders for steering and distance measurement

A 1B RCX1 2 C 3A 1B RCX2 2 C 3

Light sensor left

Light sensor right

Steering encoder

Distance encoder

IR

Distance motor

Steering motor

Line Tracking – Software• Callibration

• Measure the intensity of light and dark between the surface and the line.

• The treshold is the average between the two measurements.

• Performance• If one light-sensor goes of the line, the Mars Rover steers back in

opposite direction.• When both light-sensors are back on the line, the Mars Rover steers

straigth forward. This minimizes the number of corrections.

• Steering-angle • Controlled by a P-controller to be able to steer in different angles.

• Distance measurement• The motor-encoder measures the number of encoder increments.• The measured increments are converted to millimeters after the

end of the line is reached.

Line Tracking – Software

Mission to Mars – Strategy

• Scan the area for lakes• Raw data of the light sensors is used to achieve a

higher accuracy.• Calibration and measurement of the light sensors every

250 ms.• A driving pattern is designed to scan the area of Mars

effectivly.

Mission to Mars – Strategy

• Overall progress• Edge detection and driving pattern is working• The earth computer can read coördinates from the camera • Approaching lakes by received coördinates (work in

progress)• Motion control for driving, steering and temperature

• To do:• Finishing approaching lakes by received coördinates• Link sub-programms• Testing and debugging