trunk position

Since the stability of biped robot is intrinsically low, for improving the walking robustness to the irregular terrain and modeling error, a robust reactive force control and trunk's position/ attitude control with optimal force distribution are also considered in the course of system design.

为提高机器人对不平整路面的鲁棒性和克服系统建模误差，行走控制系统中采用了鲁棒地面反力控制器和基于地面反力最优规划的姿态控制策略。

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Action: Lean the trunk forward slowly and you will feel stretching on lower back ( Fig6), keep breathing and holding the position for30 seconds.

动作：身体慢慢向前弯曲，你会感觉到背部被拉伸的感觉（图6）。

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