COMS 4733 - Team Lab 1, due 2/6/07 before class

MoverGUI

Preliminaries

Download and read the PER robot documentation. It can be found at http://www.cs.cmu.edu/~personalrover/PER/
Install the PER API and the Java 2 SDK on your machine. The PER documentation has details. Compile the PERFilesystem.

when compiling PER/basicGUI/TestSuite.java, if you get an "incompatible types" error on line 1700 try this: go into the file at line 1665 and change the declaration from float to double

Download and compile MoverGUI.java and PERController.java.

Description

(100 pts) We would like you to implement the robot control logic for MoverGUI, displayed below:

The interface should function as follows:

when the user clicks within the window, waypoints are added to the path for the PER to follow
when the Reset button is clicked, the path is removed
when the Follow Path button is clicked the PER will drive along the path. In driving along the path, the PER must first rotate towards the proper direction, and then drive directly forward.
after the user has followed a path, the display of the PER (as represented by the red arrow) will be updated correctly, relative to its starting position and orientation.
when the Close Path checkbox is checked, the path will be closed, meaning at the end of following the waypoints, the PER will drive from the final waypoint back to the starting position.
when the Take Images checkbox is checked, the PER will take an image (using the onboard webcam), at each waypoint, as it traverses the path.
Note: You should have a scaling factor in your code that makes the conversion from distances on the screen (expressed in pixels) to real-world distances. Experiment to find something reasonable.

API Suggestions: Use TurnToAction to first rotate the PER to the correct direction, and then use DriveToAction to drive the appriopriate distance. Do not use the DriveToAction's theta arguement (set it to 0); certain values seem to crash the PER's onboard software. Also, when calculating the angle to travel, it is recommended to use java.lang.Math.atan2, not java.lang.Math.atan. The difference is that atan accepts only the final angle (limiting the range to -pi/2 to pi/2), whereas atan2 accepts both the numerator and denominator. This way the actual angle is correct, relative to the signs of the two expressions. For example, calculating the angle between the origin and (1,1) would return the same angle as (-1,-1) using atan ((1/1) = (-1/-1)).

Odometry error and calibration: when your interface is completed, define a closed path and ask the robot to drive along multiple times. Notice how positioning error accumulates each time around the circuit. After a couple of times around the circuit, the robot might end up in a completely different position relative to the starting position, due to the accumulating odometry error. This might be partly corrected by carefully calibrating the robot. Read the PER Calibration documentation and check your robot's calibration.

Physical access to the robots: we are in the process of setting up the environment where you can run your programs on the PER robots. While we will try to provide as much access to the robots as possible, we still encourage you to develop and test off-line as much of your code as you can, and move on to running the robots once your code is stable and in good condition.

Extra Credit

Use the PER's infra-red range sensor to check for obstacles. While the PER is following the path, if an obstacle is detected in front of the robot, the PER must stop and the MoverGUI must inform the user that an obstacle was detected.
After an obstacle has been detected the PER must find a way around it and than continue on its path. Assume the obstacle is cylindrical and of known radius (which you can measure), and use range sensor readings to determine its location. For example, while panning the range sensor left to right, store three readings: the leftmost reading of the obstacle, the one that is closest to the robot, and the rightmost reading. You can than fit a circle to these points to determine the location and size of the obstacle.
Once you have determined which direction the PER will take around the obstacle, add one (or more) new waypoint(s) on the path so that the PER will navigate around the obstacle and then continue along the previously defined waypoints. Be sure to leave enough space for the body of the robot to clear the obstacle. See the figures for an example:

An obstacle is detected while the robot is driving along the specified path.

We know the obstacle has a cylindrical shape; by panning the range sensor the robot acquires the range readings of multiple points on the object.

A circular shape is fitted to the points described above, giving the robot a description of the obstacle. A new waypoint is added to the path taking the robot around the obstacle.

Note: Full extra credit is given when the the program can successfully locate the cylindrical object. Partial extra credit will still be given if the PER is able to at least avoid and drive around the object, if it cannot be precisely located.

Submission

Deadline: 2/6/07 before class starts
What to submit: all your source code. Also attach a README file with detailed compilation instructions, and your custom Makefile (if any). Please put all your files into an archive bearing your group's name (RedTerror_hw1.zip for example). If you use eclipse, feel free to just export an archive file of your workspace.
How to submit: via email with "[CS4733]-HW1" in the subject line to dal2103@columbia.edu.