雙足機器人之控制與自然步態

Abstract

中文摘要 本論文主要是研究人類的走路姿態並且應用在本實驗室開發的人型機器人。研究主要是建立可應用的零力矩點的軌跡、重心在垂直方向的軌跡、以及動量補償器。 一般應用於人型機器人的零力矩點軌跡集中在腳底板中央，並且在換支撐腳時軌跡瞬間移動到此支撐腳，因此容易造成速度和加速度不連續；所以我們提出改善此零力矩點軌跡。藉由改善過後的軌跡可以讓人型機器人行走時更加穩定。利用Preview Control 生成的重心軌跡可以自由地調整重心在垂直方向的位置，使人型機器人不必總是彎著膝蓋走路，減少能量的消耗。人型機器人的自然步態規劃綜合了上述的控制器，再對逆運動學的演算法改善。本論文提出兩個方法來達到腳趾彎曲和腳跟著地，再將兩個方法做模擬和比較。 在物理環境模擬方面我們利用ADAMS進行，而所有的控制程式皆在MATLAB上撰寫，兩者的連接是用MATLAB上的 Simulink。實作方面，我們也自行開發人型機器人，搭配新設計的腳底板結構。所有機構皆由SolidWorks和CATIA 來設計並作應力分析。

This thesis examines the walking motion of human beings and applies its findings to a humanoid robot developed by our laboratory. Our goal is to construct the usable Zero Moment Point (ZMP) trajectory, a Center of Gravity (COG) trajectory in the vertical direction, and momentum compensation. Conventional ZMP trajectories applied to humanoid robots are usually located at the center of each foot pad, shifting instantaneously to the new supporting leg as support changes from one foot to another. Velocity and acceleration become unsmooth. We used Preview Control to generate a COG trajectory with the ability to arbitrarily adjust position in the vertical direction. Observations of human walking motion enabled us to plan COG trajectory with continuous smooth change of velocity and acceleration. The robot now has no need to keep its knee joints constantly bent, and therefore consumes less power. Its natural walk is a result of integrating the adjusting ZMP and COG trajectory controls by using the modified inverse kinematics algorithm. This thesis proposes two methods to derive the toe-off and heel-contact motions necessary for a natural walk. The proposed algorithms are justified through simulation and experiments. Our simulation physical environment was constructed on MSC ADAMS, and all controlling functions were built in MathWorks MATLAB. The two software environments were connected by Simulink in MATLAB. We also developed a humanoid robot with new foot pads to generate a natural walk. All mechanisms were designed in Dassault Systems SolidWorks, and stress analysis performed using Dassult Systems CATIA.