本研究旨在透過階層化控制架構與步態規劃使雙足機器人可以達成穩定行走。透過階層化控制架構可將機器人控制分為和上層質心軌跡追蹤控制器與下層機器人全身控制器（Full-Body Controller），使用此控制架構的目的是為了能利用更具成本效益的硬體設計，機器人的髖、膝關節致動器皆使用速度伺服控制，踝關節則使用串聯彈性致動器做力矩伺服控制。具體地說，下層全身控制器利用速度伺服控制來穩定機器人姿態與質心高度，所以機器人動態才可以定錨為一簡單的雙質量倒單擺物理模板；上層控制器則利用腳踝力矩讓機器人質心可以追蹤基於此模板產生的參考軌跡。為了減少擺動腳動態對行走穩定的影響，我們使用雙質量倒單擺的另外一個形式－雙質量滑車模型來規劃擺動腳軌跡使得零力矩點（Zero Moment Point, ZMP）可以在整個行走週期都存在於穩定區域內。我們將此控制架構實現在實驗室所開發之雙足機器人原型機，並利用一系列實驗包含：雙足平衡、單腳站立、原地踏步和向前步行來驗證控制性能。

　　This thesis aims to achieve stable walking of the bipedal robot by a hierarchical control structure and walking pattern planning. The hierarchical control structure is composed of a high-level Center of Mass (COM) trajectory tracking controller and a low-level full-body controller. Such a control structure is meant to exploit a cost-effective hardware design which uses velocity servos for knee and hip actuation but uses SEA (serial elastic actuator)-based torque servos for ankle actuation. Specifically, the low-level full-body controller applies the velocity servos to stabilize the robot posture and the COM height so that the robot dynamics can be anchored to a simplified template of a two-mass inverted pendulum. The high-level controller applies the torque servos to make the COM track a reference trajectory generated by the template. To reduce the influence of the swing leg motion on the stability, a cart-table model with an augmented mass, which is an alternative form of the two-mass inverted pendulum model, is used to plan a swing-leg trajectory so that zero moment point (ZMP) of the robot can remain within the stability region throughout the walking cycle. The controllers are implemented on a prototype bipedal robot developed in the laboratory and experiments including balancing, standing on one foot, stepping in place, and walking forward are conducted to validate the control performance.

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