12 dof biped powered by 4xAA batteries

I printed another set of plastic parts with some minor corrections and added ball bearings to the joints for frictionless rotation. I've also added some rubber bands to have less cable clutter from the servos to the servo shield.

The main improvement is the use of a 4xAA battery pack (rechargeable Energizer, 2300 mAh each) to power the Arduino Nano and the servo shield, soldered to an on/off switch to power the robot. It's contained in a 3D printed enclosure for the body to secure the batteries and the servo connections.

It's now 24 cm high and weights 344 grams.

My fear of the SG90 servos not being able to provide enough torque was unfounded since the robot can easily stand and crouch. But there is a lot of slack in the joints and with the added weight of the batteries it makes the robot very unstable and basically unusable.

The problem seems to come from the horns that are not secured firmly enough wrt to the axis, probably because it's all made of plastic. For a set angle the horn doesn't stay firmly in place and there can be some degrees of slack, which adds up to make the robot very unstable.

I guess the best option would be to try with servos that use metal joints, like the MG90 or MG90S for a not too expensive solution or the MG995R that seem to be often used for robots. But with that many servos the total price will skyrocket.

Another option would be to compensate in software and adapt the torque continuously to maintain balance, but it doesn't look really optimal in terms of energy consumption.

Sad.

Видео 12 dof biped powered by 4xAA batteries канала Frédéric Lopez