Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/8055
標題: 雙手臂輪式自走機器人之動態建模與追蹤控制
Dynamic Modeling and Tracking Control of a Nonholonomic Wheeled Mobile Manipulator with Two Robotic Arms
作者: 鄭孟筆
Cheng, Meng-Pi
關鍵字: Nonholonomic system;非完整拘束系統;Backstepping Control;Mobile Manipulator;Lagrage's equation;倒逆步控制;自走機械手臂;拉格蘭吉方程式
出版社: 電機工程學系
摘要: 
摘 要
本文探討輪式自走機器人的動態建模方法學與追蹤控制器設計問題。系統由輪式自走車與兩具三軸剛性機械手臂所組成,相較於一般機械手臂及自走車,更能廣泛應用在各種領域。但由於系統的輪式結構,引發非完整拘束(Nonholonomic constraint)特性,限制其側向移動的能力,導致一般平滑狀態回授控制法則的不適用性;再加上系統結構複雜以及機械手臂與自走車之間相互動力學藕合影響,更造成系統正確模式化與控制器設計的困難。
本文首先利用具有乘子(Multiplier)的拉格蘭吉方程式(Lagrange's equation)以及符號運算數學軟體,有系統的推導出完整動態模式與拘束方程式。並將系統解藕合成三個子系統,探討彼此相互關係。進而分析系統的結構特性如矩陣反對稱性(Skew-symmetricity)等,並將其充分應用在追蹤控制器的設計。同時簡化系統模式與其他研究成果比較,以證明模式之正確性與廣義性。
接著利用所提出完整動態模式,並拓展倒逆步技術(Backstepping technique)與過濾誤差方法(Filtered error method)的觀點,藉由李阿普諾夫定理(Lyapunov' theory)設計出全域漸近穩定路徑追蹤非線性控制器,其控制法則能夠完全處理系統的非完整拘束特性以及完全補償各子系統間的藕合效應,同時證明系統的閉迴路穩定特性。
最後,利用MATLAB程式模擬驗證,分別探討系統在直線、圓形及任意軌跡等任務下響應,結果顯示車體與機械手臂均能同時作動,達到位置與速度的路徑追蹤要求,而且各子系統之間交互動力學影響亦能被完全補償,故證明本文所提系統模式的正確性與控制法則的優異性。同時顯現在計算負荷、嚮應時間、追蹤誤差等指標上似乎較其他控制法則如類神經網路、回授線性化等策略,更具潛能。

Abstract
This thesis develops methodologies and design techniques for modeling and tracking control of a wheeled mobile manipulator (WMM). This mobile manipulator system is typically composed of two rigid manipulators with three links mounted on a wheeled mobile robot. Compared to mobile robots and traditionally fix-based manipulators, this system is able to perform versatile missions in various applications. Owing to the wheeled structure, the nonholonomic constraints are introduced into system models to limit lateral mobility, thereby resulting in infeasibility of the smooth static feedback control laws. Meanwhile, exact modeling and controller synthesis of the WMM are nontrivial due to not only the complex system structure, but also coupled dynamics between mobile platform and manipulators.
The exact dynamic models and constraint equations of the vehicle are derived based on the Lagrange's equation with multiplier and the commercial symbolic software packages. In order to understand the effects of the coupled dynamics, the system is decomposed into three subsystems. Structural properties (e.g., skew-symmetry) of the WMM are well analyzed, which are very useful in synthesizing tracking controllers for the type of vehicle. To insure the correctness of the proposed models, the models can be reduced to match some well-known models.
Using the backstepping technique and the filter-error method, the globally asymptotically stable tracking controller based on the Lyapunov theory is proposed to make the vehicle follow any smooth desirable trajectories. This control law is capable of dealing with nonholonomic constraints and fully dynamic interactions between mobile vehicle and manipulators.
Several path following tasks including linear, circular and arbitrary trajectories are well explored in computer simulation utilizing MATLAB. These results show that both the mobile base and arms asymptotically track any smooth desired position and velocity trajectories simultaneously, and the coupled dynamics between each subsystem is fully compensated. Four simulation results also illustrate the effectiveness of the proposed models as well as the feasibility of the proposed control scheme. Especially, considering computation loads, transient system responses and tracking errors, the proposed control laws seem to outperform others control strategies, such as neural networks and feedback linearization.
URI: http://hdl.handle.net/11455/8055
Appears in Collections:電機工程學系所

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