Last post was about wheel encoders calibration. Following the Parallax instructions, I got 64 bytes of data and 3 constants which are specific to my robot.
Today, I tried the provided "proactive" navigation. The "Wheel_Motion.bs2" demo program has been modified to meet the configuration of my Boe-Bot :
- Calibration data bytes and constants
- Pin assignment
This routine works quite well ! The program starts with a 1 meter square motion, each side being achieved with speed ramping, a angular correction. The robot finishes its path with a constant error : a 3 cm gap and always in the same direction. This value could probably be improved with a better calibration. I could change the rubber bands on the wheels or execute the calibration procedure on the floor (instead of the desk) to get the same friction...
Please note that to get this constant level of accuracy, the start position has to be constant either, and the wheels have to be at the same angle relatively to their sensor.
Then I ran the complete demo sequence : square, octagon, 2 spins. The final position and azimuth are still constant. Of course, errors keep adding at each path, like always on a robot.
By reusing this program I will be able to have the robot to come back to its mission starting location. Example of behavior : leave the base to find a labeled obstacle, push it down, come back to base". To do that, it will have to monitor/record its path during the beginning of the mission.
This should the next step in this encoders training...
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