Mini Bi-Ped construction

On this page I try to explain how the Mini Bi-Ped was built. In order to understand why only one motor is needed to create a walking movement (the other motor mentioned is used for steering), we look at the walking function of biped increment #2. Here, the upper and lower leg oscillate at the same frequency, and the phase is shifted with respect to each other. When this phase is chosen constant and the amplitudes are kept constant as well, the only variable left is the oscillation itself. This oscillation of legs can be achieved by a rotating crankshaft, powered by just one (geared) motor. We just have to add some levers in order to connect the legs to the crankshaft. See picture below.

Working principle of the leg mechanism. Red colored are the lower leg parts, the upper leg parts are colored blue. Each dot represents a rotation point.

The legs are constructed as parallelograms in order to let the biped stand during the whole phase of a step. Also a fork-like foot construction is used to prevent the Biped form falling sideward. I used Aluminum plate (0.5 mm thick) for the construction, and some copper wire for the joints.