| 摘要: | 先前計劃提出單自由度或雙自由度的三維複合式運動平台，對於該等新穎構想的空間機構，已完成初步的合成與測試，可執行路徑演生及物體導引等三維運動。並且將樞點位置或桿長設計為可調整，讓機構能於各相間切換，達到多相及多功能的目標。先前計畫的精確點或精確姿勢的指定，其個數皆少於或等於理論的最大值。本計畫將跨越此限制，著重於過多的精確點指定或精確姿勢指定時，配合最佳設計的數值搜尋方法，提出合成策略，並探討誤差等相關問題。應用最佳設計時的最主要議題為目標函數的規畫。空間機構有數組支撐腿，其接頭多為球形接頭及圓柱接頭。目標函數的標的為在各個精確點或精確姿勢的指定下，對應的移動樞點能盡量在一球面或圓柱面上。應用的技術如三點決定一圓及四點決定一球面等幾何基礎。使用投影技術可將空間關聯轉為較易處理的平面問題。對於多相的應用，可於目標函數中加上如半徑相等和球心重合等考量。另外，先前提出的”共球面曲面”及”共球面曲線”，可當作最佳設計時的等式限制式。將數組支撐腿加以組合時，所得到的空間機構可能有次序缺陷和分支缺陷，該等問題可利用構型分析以協助釐清；開發的程式須設法篩除有缺陷疑慮的機構。由於本計畫針對過多的指定，機構運轉時必有誤差。誤差值的定義除了移動樞點的理想位置與實際位置的距離外，將嘗試其他合理的定義。低自由度機構具有成本低、構造簡單、易維修及易改裝等優點。本計畫將增加可指定的精確點或姿勢的數目，使機構能大幅增廣其應用功能。藉此計畫的發展，如生產線的末端器及戽斗等，得以因需求而進行三維的運動。人們使用的健身器材或復健器材，不再侷限於呆滯的二維動作，而可如舞者進行三維且曼妙得擺動。
Hybrid platforms with one or two DOF were proposed in previous projects. These novel mechanisms have been designed, synthesized and tested, and they can execute the tasks of 3D single-phase path generation or body guidance. They can also be used to execute the tasks of multi-phase path generation or body guidance by adjusting the position of ground pivots and link lengths. In previous research, the number of assigned precision points or poses is less than the maximum theoretical values. The goal of this project is to synthesize the mechanism with the aid of optimization while the number of assigned precision points or poses is larger than the maximum theoretical values. The strategy of synthesis and the problems related to error are to be developed and investigated.Planning the objective functions is the primary concern in using optimization technique. Spatial mechanisms are equipped with several supporting legs that have mostly spherical or cylindrical joints at both ends. The goal is that all points of any moving pivots corresponding to the precision poses or precision points can lie on the surface of a sphere or a cylinder. Three points defining a circle and four points defining a sphere are the basis techniques to be used. The concept of projection can be used to convert spatial problems into planar ones. The condition of coincidence of center or equivalence of radii has to be satisfied for the application of multi-phase. Furthermore, “sphere-point surface” and “sphere-point curves”, being proposed in previous research, can become the equality constraints in optimization search.The spatial mechanisms that are equipped with several supporting legs may have the problems of order-defect and branch-defect. These problems can be clarified with the aid of configuration analysis. The programs to be developed should be able to get rid of the mechanisms that may have any defects. When the synthesized mechanisms are used to execute body guidance or path generation, the existence of error is expected since the number of assignment is larger than the theoretical maximum value. The error can be defined as the distance between the ideal positions of moving pivots and their actual positions. Defining error in other ways will be tried as well. Low DOF spatial mechanisms inherently own the advantages of being low-cost, simple to design, and easy in maintenance as well as modification. The execution of this project results in that more number of precision points or poses can be prescribed. The advantages of using mechanism with low DOF are thus enhanced. With the achievements of this project, the end-effectors and scoops used in various industries can carry out three-dimensional movements. The health, fitness, and rehabilitation facilities currently in use are confined to dull planar motion, and they can be modified so that users can move gracefully, three dimensionally, and as dancers. |
