hi there first of all hi to every one i am new hear.
I have been trying to build my self a biped robot but i am alarmed by the cost of servos especially ones that are powerfully up to the job well i should say the final cost after buying the huge number needed for such a project, also i have found that servos do not model real muscles that well (please ref to the Lucy robot).
so what i have done is obtained an old PC CD ROM removed one of the motors and attached it to a piece of m5 threaded bar via a home made coupling and a set of grub screws. then made a small block out of aluminium that is threaded m5 all the way through of which is threaded on to the m5 rod ( making a worm screw)
So as the motor turns it turns the threaded rod which moves the Alu block down its shaft. this block pushes against a spring which in turn presses against the joint making it move. On the joint there is a pot to provide feed back. the main reason for the spring is that it makes it possible for the limb to sense when it hits something.
so far i have tested the straight lifting capability of the device at 300g lifting just straight from the Alu block vertically at a speed of 40mm/sec using a 7.6v battery. the Assembly is roughly about 60mm long and 20mm in diameter. the best thing is you can use and motor as it is all directly driven. And the whole thing took about 1hour to make with the aid of a pillar drill
has anyone else tried this??