俱即時軌跡產生功能之雙足機器人應用於不平地行走

Biped Robot with Online Trajectory Generation Walking on Uneven Terrain

林哲毅(Che-I Lin)

指導教授 ： 羅仁權

國立臺灣大學/電機資訊學院/電機工程學研究所/碩士(2014年)

https://doi.org/10.6342/NTU.2014.00040

摘要

雙足機器人與輪型機器人皆為移動平台，然而雙足機器人相對於現今常見的輪型機器人來說有許多的優點，例如，現今常見的輪型機器人僅適用於在室內較為平坦的地形行走，如果遇到地上有電源線或是小障礙物勢必需要繞路閃避，然而雙足機器人卻可以直接跨越不受地上的阻饒物影響；此外，室內環境樓層間必定有樓梯但卻未必有電梯，輪型機器人無法行走於樓梯，而雙足機器人卻可以，這也是其優勢之一。另外，如果是地形較為顛簸的室外環境，當地面凹凸不平的情況，輪型機器人更是難以克服，因此本論文致力發展俱即時行走軌跡產生功能之雙足機器人應用於不平地面行走的研究，期望將結合雙足機器人上述的優點，使其廣泛應用。
本篇論文所提出的俱即時行走軌跡產生器使用到前饋控制以及回饋控制的結合，文中將分析模擬只採用回饋控制時雙足機器人在追蹤預先規畫好的零力矩點軌跡時將發生負面效應: Initial undershoot，因此加入前饋控制採用極零對消的方式將不適任的零點消除，使其昇華成為輸出穩定軌跡的軌跡產生器，而此處的前饋控制則是使用有限項泰勒級數精準展開。
本篇論文下半部分所提出的不平穩地面行走策略首先提出了腳掌落地力控制，雙足機器人在行走時擺動腳落地時產生的衝擊力會造成機器人的傾倒，此控制系統則是盡量消除此衝擊力的影響。落地力控制之後，為了達到適應不平地面之環境，在腳踝兩個軸的部分補償了啟動電壓克服個軸之中的摩擦力，接著結合了腳底板底下的力感測器回饋以及陀螺儀感測器回饋，並且依此即時修正落地腳的行走軌跡(包含擺動腳掌落地時的位置修正、擺動腳掌落地時的方位修正)以達到克服不平地面之行走狀況。
在實驗部分也詳細且有條理地證實所提出的不平穩地面即時軌跡產生器結合前饋控制器以及回饋控制器其功能有所作用，此方法有其穩定性。

關鍵字

雙足機器人 ； 前饋控制 ； 回饋控制 ； 軌跡產生器 ； 不平穩地面

並列摘要

Biped robot is definitely a more powerful moving platform, because it can not only move indoor but also overcome some uneven ground in outdoor environments. Compared with wheeled robot in indoor environment, biped robot has greater advantagesofmoving capabilities, such as going upstairs and downstairs, stepping over obstacles, and so on. Moreover, wheeled robot can only move in flat ground. If there is a cable line or small obstacle on the ground, wheeled robot has to change its path to pass it. However, biped robot don’t need to change its walking path, it can overcome the uneven terrain by the adaptation method.
The objective of this research is to develop an online trajectory generator with foot adaptation method and pole-zero cancellation using series approximation method to generate walking patterns for walking on uneven terrain. By the use of pole-zero cancellation using series approximation method, it can overcome the sudden change of ZMP reference.
Furthermore, the pole-zero cancellation method is designed to reduce the undesirable effect which is the initial-undershoot response of ZMP output by cancelling the unstable zeros in the control system. In addition, the proposed landing control reduces the contact force effect and enhances the stability of biped walking. Besides, the online sensory feedback control system with proposed online foot adaptation method can adapt to unknown walking surface instantly. The proposed control system and adaptation method are verified and successfully demonstrated.

並列關鍵字

biped robot ； uneven terrain ； feedback control ； feedforward control ； trajectory generator ； pole-zero cancellation

參考文獻

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