線性倒單擺模型為雙足機器人步態生成方法之一，其特色為運算量較低且能提供即時步態生成，因此普遍應用於雙足機器人步行產生。線性倒單擺模型以機器人操作質心高度為主要系統參數。然而對於結構複雜之雙足機器人，操作質心高度之預估並不容易；不恰當的操作質心高度設定將影響到機器人步行時之穩定度與左右晃動程度。因此，機器人操作質心高度之自我調整將對於步行穩定度有著重要的影響。有鑑於此，本研究以一裝置於機器人髖部中心之陀螺儀量測髖部平面之角速度變化，並定義基於步態週期之陀螺儀穩定度指標（Cycle-based Gyro Stability Index；CBGSI）。此一CBGSI除了用來評估每一步態週期之穩定性外，並可以此一指標實現一閉回路比例控制器作為調整操作質心高度參數之依據。最後基於此一自調適操作質心高度演算法實現於一高52公分具19自由度之小型人形機器人平台之步態生成，達成機器人自調適找尋適合之操作質心高度參數，並且實作全向步行。

Linear inverted pendulum model (LPIM) is usually used to generate real-time bipedal locomotion of a humanoid robot because of considering lower computational loads. LIPM uses the operational height of center of mass (CoM) of a biped robot as a primary parameter to generate locomotion trajectory. However, the operational height of CoM is hardly determined because of complicated mechanical structures of biped humanoid robots. Improper operational CoM height setting would induce locomotion stability problems. In addition, extra masses applied on the robot will also alter the operational CoM height setting. Therefore, self-adjustment of the operational CoM height is necessary to the study of bipedal locomotion stability. In this study, a gyro sensor is placed at the center of hips to measure the variation of angular velocities of the robot’s hip plane. The angular velocities in a cycle are further used to define the cycle-based gyro stability index (CBGSI). In addition to evaluate the stability of bipedal locomotion, the CBGSI is also capable of realizing a closed-loop proportional controller to automatically adjust the operational CoM height setting to improve the stability of bipedal locomotion. Finally, a 19-degrees-of-freedom biped humanoid robot with 52 cm in height is developed in this study to evaluate the performance of the proposed operational CoM height adjustment approach based on an omni-locomotion controller.

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