Flip gait synthesis of a biped based on Poincare map

A novel manner of one-legged bipedal locomotion (i.e., ballistic flip) is proposed in this paper. A flip is composed of three sequential stages: stance phase, flight phase and touchdown. During the stance phase, the two objectives of control, constant locomotive speed and taking off at the end of stance phase, are achieved via a control algorithm based on nonlinear feedback linearization. The flight phase needs no active control. Combining dynamics of the three stages, we construct the Poincare map numerically for a complete flip gait, and then use a gain-tuning strategy to stabilise the fixed point of the Poincare map corresponding to an unstable cyclic flip gait One simulation result is given to verify the effectiveness of this strategy.