What I am experianceing is very weird but I will try to explane it as best as I can.
I have a simple robot arm with 4 Degrees Of Freedom (DOF). This is not a robotics problem but thought it would be better to write what I am doing. I am using a Turnigy TGY-S901D servo motor at each DOF. Each motor has an encoder that you send a command (via RS-485).
So look what happened a few days ago. I plugged it in my computer and send a command to the base motor (first DOF) one time and it worked find. Then did the same thing to the second DOF, again everything was fine. I did this for all the motors (all the DOF).
Then tried to move the first DOF again but it moved slower and not to the correct position, it needed a few degrees more. Send the same command (after I put the motor to its origin position) and it moved even slower and was even more far from the end goal. After 3-4 commands, it ended up not being able to move at all. I can hear it trying to move but with no success.
The same thing happened, after, with all the other motors. With each new command they moved slower and with a bigger error.
After that, I left the robot arm for a few days. Today I tried again to use and the first DOF does not work at all but all the others acted they way I discribed above. The first time everything worked fine and every new command made them slower.
Important NOTE: In the past I was able to use it just fine. Never had this problem. This problem appeared last week for the first time.
It is like it gets tired. Does anybody know why this is happening?