Comment by gene-h

It's unfortunate that we still don't have cheap torque controlled robot actuators. Controlling force rather than position led to a drastic improvement in walking robots. I would also highly recommend using something beefier than an arduino to control a walking robot as most approaches to walking robots today rely on performing fast optimization. MIT's minicheetah has used a control approach that involves simulating the robot about 0.5 seconds into the future 50 times a second.