Modifiable walking pattern generation using real-time ZMP manipulation for humanoid robots

Complex navigational commands require a walking pattern generator that is able to modify the pattern at any point in the walking gait. This paper utilizes the 3D-LIPM (linear inverted pendulum model) for generating a walking pattern, but introduces a method that allows for manipulation of the ZMP over the convex hull of the foot polygon whilst in single support phase. This permits a range of dynamic walking states that are not achievable using the conventional 3D-LIPM. These walking states are defined as a feasible region. A real-time algorithm is then developed, which follows the cue from a complex navigational command exactly when the desired walking state is in the feasible region and chooses the nearest feasible motion when it lies outside the feasible region. The proposed scheme is both simulated and implemented on the humanoid robot HanSaRam-VII developed at RIT laboratory, KAIST.