Real Time Biped Walking Gait Pattern Generator for a Real Robot

The design of a real time and dynamic balanced biped walking gait pattern generator is not trivial due to high control space and inherently unstable motion. Moreover, in the Robocup domain, robots that are able to achieve the goal footstep in a short duration have a great advantage when playing soccer. In this paper, we present a new technique to realize a real time biped walking gait pattern generator on a real robot named Nao. A Zero Moment Point (ZMP) trajectory represented by a cubic polynomial is introduced to connect the goal state (the position and the velocity of the CoG) to the previous one in only one step. To apply the generator on the real robot Nao, we calculate the compensation for two HipRoll joints in a theoretical way by modeling them as elastic joints. The nao of version 3.3 is used in the experiments. The walk is intrinsically omnidirectional. When walking with step duration 180ms, the robot can respond to the high level command in 180ms. The maximum forward speed is around 0.33m/s. The maximum backward speed is around 0.2m/s. The maximum sideways speed is around 0.11m/s. The maximum rotational speed is around 90°/s.