I have just constructed my first AL5D robotic arm (with wrist rotate). I switched it on and connected to it with lynxterm and later with flowbotics studio.
In both cases I hear a noticeable “hum” that is pretty much continuous. It does not occur if I switch on the power without being connected to a PC.
Have I tightened a horn screw too much, or are my bearings too tight? I am concerned I might be putting too much load on the servos. Or is some servo noise normal?
I haven’t done anything fancy yet, just moved each servo to show they are all working. Mostly the motion is smooth, though there is a little jumping at one extreme of the base rotation. With the springs in place, the arm rests a little below 90 degrees, as though the arm weight is a bit much for the springs.
For servos to keep their position, they need to be constantly powered, and as such, they may hum. If you hay them on the ground with no load, you’ll see that once they reach their final position, there’s no load trying to move them, and they will not need to receive much power at all (and will be silent). If it is really a loud hum and you suspect something’s wrong, can you take a video?
Thanks for the reply. I have a video I took on my iPhone, unfortunately movies with extensions of *.mov or *.m4v cannot be uploaded, so I will try again tomorrow.
Thanks for your patience.
I also noticed that I was stretching one cable alarmingly and pulling on the circuit board. So I will fix that too.
I am controlling the motion with sliders in the FlowBotics Studio sample program. I have not done anything to calibrate the arm yet. The hum starts when I move the base servo slider and continues until I switch off the arm at the circuit board.
The sound isn’t great, so you have to turn up the volume - but you can gauge the level of the hum in comparison to the other servo sounds as the arm moves. The near constant hum is the noise I am referring to. If that is normal, I am fine with it - I just don’t want to break anything.
Also, there is a definite “twitch” at 2 mins and 31 secs as the base rotates to an extreme position - the relatively smooth motion jumps significantly.
The hum is coming mostly from the large shoulder servo? Notice how when the arm is at 90 degrees the hum is greatly reduced - this is because the servos does not need to provide much torque. That hum is normal, and it looks like you have the arm setup normally. The sudden lurching at 2:31 is a bit harder to explain and depends on the signal it received.
