Derek: 2007 05 22

Progress Update

Actuator Subsystem

1. The PIC16F76 microcontroller units arrived a few days back after placing order from the previous week. We programmed them accordingly and fitted them onto the slave controllers. The subsystem is later tested and all actuators are working properly.

2. Things to be done: Calibration of the terrain controlled by the actuators (hardware) with the virtual terrain (software). Checked with Roger on the rough procedure. We will have to look into the codes and adjust the mathematical equations accordingly to map the hardware to software.

Mechanical Arm Subsystem

1. Tested the existing master and slave controllers. Found out that the master controller could not work as it was burnt the last time. Had to solder a new master controller using the schematic diagram from the documentation. Tested the new master controller and it works.

2. Also, one of the slave controller did not work when it came to rotate the motor. Since the I2C connection works, we suspected that certain components which were controlling the motor could have been damaged. Upon checking these components, we realised that the L297 (stepper controller) was damaged. This was replaced and the slave controller tested again. It is working properly now.

3. We had to wait for the manufacturers of the mechanical arm to come down to fix the arm to the Metazoa Ludens system. After that, we proceeded to secure the master and slave controllers on the arm such that the wires are organised properly and do not interfere much with the camera tracking subsystem and the moving arms. Some of the wires would need to be painted black or covered with a black cloth so that they do not interfere with the tracking devices. See figures below for the fitted mechanical arm.

DSC00364.jpg DSC00366.jpg

4. We began to test the motors to ensure that the arms are working properly. The z-arm was working properly but the x- and y- arms were giving problems. The motors will not spin back and give out a sound similar to the one we encountered before when we were working on the actuator subsystem.

5. Like the actuators, we thought that that the couplers could have dislodged. But this wasn't the case upon initial inspection. We later suspected that either the worm axel or the coupler could have gotten stuck somewhere and we decided to take the structure apart to try to fix the problem. However, after removing the structure, we realised that nothing was blocking the worm axel or the couplers.

6. With the structure dismantled, we could easier identify the problem and it was with the couplers specifically as they constantly dislodge (due to gravity) whenever the motor spins the arm back to initial position. We tried to secure the couplers firmly together but it didn't work. We decided to call the manufacturer to work on it as they might have a better insight of what is wrong. See diagram below for an image of the coupler.



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