AX-12 Problems

[JavaRN]

I am curently turning my bioloid into a soccer bot, and I made some stractural changes - bigger head to fit a cmucam and larger feet (1cm wider). However after some days working with this bot, servos 15 and 16 it is as if they cannot withstand the robot weight and the robot starts falling backwards during walk (before it didn't fall backwards), and if you force the servos they are not as stiff as the others while the robot is on. Are both servos fried? or is it a gear problem?

Thanks for your feedback.

[StuartL]

Thermal shutdown on the servos, they're working too hard. Restructure the gait so those servos are working less hard and the problem should go away.

[JavaRN]

Thanks StuartL, what I did was to add an accellerometer and sense the vertical position of the robot and I am titlting the head forward a little, and moving servos 11 and 12 1 step forward everytime the robot goes "backwards", and it seems to have worked somehow, but I am facing another problem, which is the battery - It is wearing out after a couple of minutes, in fact I am thinking of replacing it with a Lipo and I am a little reluctant to do so as from what I read, if mishandled they can blow up and beleive me the last thing I want is to blow up my bot!

[StuartL]

I've made my opinions on the standard battery and charging circuit well known in another thread somewhere...

We made a Robotis battery catch fire trying to use the standard charging circuit to get charge into it. You don't want to use the onboard charger, and if you're using an off-board charger and have the money get a decent 3-cell (3S) LiPo battery and a decent charger.

I STRONGLY recommend the CellPro 4S charger from FMA direct. It'll even happily charge the battery from the Robotis power brick if you make up an appropriate cable.