Humanoid robot motions have been rapidly improving over the past two years. Regular readers of Robots Dreams have seen quite a few videos that illustrate the smooth motions that the new Kyosho MANOI AT01 can achieve.
It turns out that the AT01's close "cousin under-the-skin", the Kondo KHR-2HV is also able to produce very human like motions, as you can see from the video clip below.
While they use different servo models with different torques and a slightly different controller board, both the AT01 and the KHR-2HV take advantage of Kondo's second generation technology to make it possible to create more realistic movement.
With first generation designs, like the KHR-1 and the Hitec Robonova-1, the operator would define the desired position of any given servo in roughly one degree increments. Newer designs, that we arbitrarily refer to as 'second generation', allow the operator to define the desired servo position with much finer control - down to small fractions of a degree. This results in much better posture and positioning, as well as more stable walking and movement in general.
That doesn't imply that the servos can consistently be moved in tiny increments - physical limitations like inertia, gear train hysteresis, slack, and friction can never be ignored. However, if the servo is moving over a range of degrees, it is possible to control it's final position much more accurately and finer than any first generation controller/servo combination.
Here's a good example taken during a Kondo KHR-2HV demonstration at the ROBO-ONE 10 competition in Nagai: