本文選題：可變剛度 + 非線性�。� 參考：《哈爾濱工業(yè)大學》2017年碩士論文

【摘要】：可變剛度的柔性關節(jié),因其剛度可調的特性,相比傳統(tǒng)的剛性關節(jié)和單純柔性關節(jié)有更強的環(huán)境適應性,特別在人機交互較多的場合擁有極高的應用價值。但是剛度可變也帶來了結構復雜,剛度穩(wěn)定性差等問題,而且,當前已有的變剛度機構中,剛度同多個參數(shù)間皆為非線性關系,使得關節(jié)剛度辨識困難,控制器難以準確實現(xiàn)剛度動態(tài)調節(jié)。本文針對上述問題,設計了一種利用機構間幾何關系實現(xiàn)剛度變化的新型變剛度機構,并在此基礎上完成了剛度動態(tài)可調的給定值控制系統(tǒng)的研究與設計。首先,針對變剛度原理中存在的非線性問題,本文提出了一種類曲柄滑塊機構,利用支點運動時機構間的幾何關系預壓縮彈簧,實現(xiàn)了剛度關于支點偏移量的近似線性變化。該原理中引入的支點-滑塊-滑動軸承的壓縮形式解決了現(xiàn)有的支點-滑槽結構中的摩擦間隙,運行不夠穩(wěn)定等問題,同時,支點依靠行星輪機構驅動,也使得關節(jié)整體結構更為緊湊。在此基礎上,課題對各功能模塊進行分割,設計了包括剛度調節(jié),剛調傳動,主傳動以及關節(jié)附屬測量等功能模塊的結構。其次,針對關節(jié)系統(tǒng)剛度模型中仍存在的非線性特性,利用剛度同支點偏移量之間的線性關系,對剛度模型進行了參數(shù)解耦合和泰勒展開處理,完成了剛度曲線的擬合。在此基礎上,考慮到關節(jié)運行中輸出剛度動態(tài)調整的需求,設計了基于軌跡發(fā)生器的給定值控制模式,實現(xiàn)了需求剛度、位置同電機軌跡之間的映射。之后,對控制算法的軟硬件實現(xiàn)進行了研究,針對系統(tǒng)通訊、供電、電路集成化等要求,設計了具有命令處理、CAN通訊、RS485通訊、電壓轉換、狀態(tài)指示等功能的硬件電路,并依據(jù)算法對其軟件實現(xiàn)進行了編寫和優(yōu)化,完成了控制命令從上位機到下位機再到運動調節(jié)模塊的傳輸與反饋,實現(xiàn)了控制系統(tǒng)的總體設計。最后,基于上述結構和控制系統(tǒng),搭建了單關節(jié)實驗平臺,設計了靜態(tài)剛度辨識、動態(tài)剛度跟隨實驗以及多種負載、剛度、需求信號下的位置跟隨實驗,對關節(jié)剛度特性和位置特性進行了實驗驗證,證實了課題設計的控制器在一定范圍內實現(xiàn)剛度和位置連續(xù)調整的可行性。
[Abstract]:Because of its adjustable stiffness, flexible joints with variable stiffness have stronger environmental adaptability than traditional rigid joints and simple flexible joints, especially in the case of more man-machine interaction. However, the variable stiffness also brings about the problems of complex structure and poor stiffness stability. Moreover, in the existing variable stiffness mechanisms, the stiffness and several parameters are nonlinear, which makes it difficult to identify the stiffness of joints. It is difficult for the controller to realize the dynamic adjustment of stiffness accurately. In order to solve the above problems, a new type of variable stiffness mechanism is designed, which utilizes the geometric relationship between the mechanisms to realize the stiffness change. On the basis of this, the research and design of the dynamic and adjustable stiffness control system with given values are completed. Firstly, aiming at the nonlinear problem in the principle of variable stiffness, a kind of crank slider mechanism is proposed in this paper. By using the geometrical relation between the mechanisms when the fulcrum is moving, the precompressed spring is used to realize the approximate linear variation of stiffness with respect to the offset of the fulcrum. The compression form of fulcrum-slider-sliding bearing introduced in this principle solves the problems of friction clearance in the existing fulcrum-chute structure and its operation is not stable. At the same time, the fulcrum is driven by the planetary wheel mechanism. It also makes the whole structure of the joint more compact. On the basis of this, the thesis divides the functional modules and designs the structure of the modules including stiffness adjustment, rigid transmission, main transmission and joint accessory measurement. Secondly, according to the nonlinear characteristics of the stiffness model of the joint system, using the linear relationship between the stiffness and the offset of the fulcrum, the parametric decoupling and Taylor expansion of the stiffness model are carried out, and the fitting of the stiffness curve is completed. On this basis, considering the need of dynamic adjustment of output stiffness in joint operation, a given value control mode based on trajectory generator is designed, and the mapping between required stiffness, position and motor trajectory is realized. After that, the hardware and software realization of the control algorithm is studied. According to the requirements of system communication, power supply and circuit integration, the hardware circuit with command processing can communication and RS485 communication, voltage conversion, state indication and other functions is designed. According to the algorithm, the software implementation is programmed and optimized, and the control command is transmitted and feedback from the upper computer to the lower computer to the motion adjustment module, and the overall design of the control system is realized. Finally, based on the above structure and control system, a single joint experiment platform is built, and static stiffness identification, dynamic stiffness following experiment and position following experiment under various loads, stiffness and demand signals are designed. The stiffness and position characteristics of joints are verified by experiments, and the feasibility of continuous adjustment of stiffness and position is verified by the controller designed in this paper.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TP242

【參考文獻】

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1 王偉;劉立冬;魏來;劉斐;，

本文編號：1906862