Praktikum Autonome Agenten

Project4: Acceleration sensor package

Function:
The package has to provide methods for sensor calibration and queries on distance, speed, acceleration, tilt and roll, which can be directly measured ore indirectly be calculated from the sensor. Furthermore the package has to provide methods for a visualization of the sensor data. Finally the sensor's abilities have to be evaluated with the odometry measurements of the robot and the position estimate of the Laser Range Finder (LRF).

Getting started:
Use the CS Freiburg software package for measuring the robot’s odometry and accurate position with the implemented line matching algorithm that matches lines extracted from scans taken by a Laser Range Finder (LRF). You can get the package from a CVS repository by the following commands:

$>cvs co accSensor
$>cvs co csfreiburg_libs
$>cd accSensor
$>make depend
$>make

This will build the code for controlling a robot which you do not need at the beginning of the project. To just get an idea about the localization and control, simply copy the executable to the laptop mounted on the robot, type:

$>make distprak C=NAME ,where NAME is the name of the laptop you mounted on the robot (e.g. vaio4).

Then you can execute the code on the robot by exporting the laptops display to the computer you are working on. Suppose you are working at 'fernando' and on the robot we have mounted 'vaio3', then type the following:

fernando>xhost +vaio3
vaio3>setenv DISPLAY fernando:0
vaio3>accSensor/praktikum/praktikum

You can now add a new directory for your project files to the hierarchy (e.g. accSensor/accSensor). By this, it will be later easy to integrate your code to the CS-Freiburg package. This directory should contain all files for accessing the sensor and a main.cpp for testing the sensor in a standalone mode. For using the sensor with the CSFreiburg software, please modify the main.cpp in accSensor/praktikum. For a documentation of the sensor and the CS Freiburg software see:

ADXL202 Evaluation Board with RS-232 Interface,manual

Crystal, the interface for the CS Freiburg Robots, manual

Part I - Implementation of the library

The library has to execute a thread that continuously updates the internal data structure by communication with the sensor.
The following methods have to be provided:

double getTilt() returns the sensors current tilt angle in degrees.
double getRoll() returns the sensors current roll angle in degrees.
double getAccelerationX(), double getAccelerationY() returns the current acceleration in X and Y respectively.
double getVelocityX(), double getVelocityY() returns the current velocity in X and Y respectively.
double getPositionX(), double getPositionY() returns the current position in X and Y respectively.
struct timeval getTimeStamp(void) returns the time of the lastest update.
void init() starts the communication thread
void exit() closes the communication thread

Additionally a Graphical User Interface (GUI) has to be developed, that allows to calibrate the sensor and to visualize the output of the above values over time.

Part II - Integration with the CS Freiburg software

For a later evaluation of the sensor it is necessary to make the sensors output available in the CS Freiburg software. Therefore implement the appropriate functions in sensors.cpp for accessing the sensor from user applications. Test the interface by modifying paraktikum/main.cpp so that it draws the measurements inside the crystal window.

Part III - Evaluation

We want to know how accurate the sensors measurements are compared to the robot's position estimates. Thus perform the following evaluations:

Position comparison of odometry, LRF and acceleration sensor.
Velocity comparison of odometry, LRF and acceleration sensor.
Error of tilt/roll measurements.