具力回饋及阻抗控制之機器人手臂研究

The Development of Force Reflective Impedance Control for a Humanoid Robot Arm

易春億(Chun-Yi Yi)

指導教授 ： 羅仁權

共同指導教授 ： 黃漢邦

國立臺灣大學/工學院/機械工程學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.10936

摘要

在任何一個環境之中，與機器人有所交流的不外乎人與物。就類人形機器人整體架構而言，與人和物接觸最頻繁的就屬其四肢。本篇論文重點為發展力回饋補償控制與阻抗控制(Force Reflective Control and Impedance Control)並透過模擬與實驗測試驗證此控制方法兼具精準定位以及順應環境之效果，以作為類人形機器人四肢底層控制架構。
以六個自由度之類人型機器手臂做為實驗的研究對象、以運動控制卡做為運算核心，將演算法燒錄至運動控制卡，確保運算時脈的穩定性，並利用數位轉類比的訊號來實現扭矩控制的演算法。在演算法中，結合發展出的力回饋補償控制與阻抗控制使手臂達到順應性的現象。而在各個演算法中，各自擁有相對應的應用。
力回饋補償包含手臂多軸的重力補償與輔助力等補償控制，在重力補償部分，利用機器人座標轉換與三度空間向量投影找出其通解，簡化重力補償的難度，而輔助力上則提高了手臂的順應性，此外，補償器除了提升控制的性能，亦擴展到許多應用層面，提昇機器手臂與人的接觸式互動，如順應控制、教學(Teach & Play)、力量的反平衡控制(Force Counterbalance Control)等。
在阻抗控制上，由基本PD控制器，拓展到阻抗控制，並探討阻抗控制的相關延伸與相關手臂的研發，如：Cartesian Impedance Control of DLR與Barrett 的輕巧設計。一開始為了避免重力的影響，利用單軸為實驗平台作水平運動來驗證阻抗控制，進而發展出適應性等速阻抗控制。在補償器的加入後，將阻抗控制沿用到多軸手臂控制。
最後，結合力回饋補償器與阻抗控制，應用到按摩機器人上，讓按摩機器人達到順應性按摩，此外亦可利用教學(Teach & Play)的方式來提升按摩的重覆性與軌跡規劃速度。

關鍵字

扭矩控制 ； 力回饋補償 ； 重力補償 ； 阻抗控制 ； 適應性 ； FCC

並列摘要

Since the based concept of impedance control law and force control are similar to the control method that a human uses for motion and locomotion. Therefore, this thesis attempts to study Force reflective compensator and impedance control for physical environment and humanoid robot interaction, and construct the bottom layer control algorithm for the robot manipulator.
The experimental plant is 6 axes DOF humanoid robot arm, and the operative kernel is manipulated by motion control card. Because of motion control card, the ISR (Interrupt Service Routine) is stable and fixed while the algorithms is worked in motion control chip. Furthermore, the torque control algorithms are implemented by Digital-to-Analog converter that control card provides. In control algorithms, the robot arm achieves the phenomenon of compliance by combining force reflective compensator control and impedance control. In each control algorithm, they have respective control applications.
Force reflective compensator includes gravity compensator of multi DOF and auxiliary force/torque compensator, and so on. In gravity compensator, there is a general solution that is computed by robot coordinate transform (Denavit-Hartenberg) and vector projection of three dimension space can simplify the level of difficulty of gravity compensator. The algorithm of auxiliary force/torque can provide compliance of robot arm, while robot arm is moved by user. Therefore, besides the compensator can improve system performance of controller, the algorithms are also extended to some applications and solve the interaction between robot arm and human, such as compliance control, Teach & Play, Force counterbalance control and so on. By the way, the result of experiment is also discussed and analysis.
In impedance control, we start to use one DOF robot that just moves in horizontal plane to avoid the effect of gravity compensator. Thus, we develop the algorithm from PD control to impedance control and finally extend to the adaptive impedance control with constant velocity. After the force reflective compensator is added in control loop, the impedance control can stretch to multi DOF robot arm.
Finally, these control algorithms impedance control and force reflective compensator are combined to implement on massage robot arm, and take advantage of compliance massage. Furthermore, we also demonstrate a method of “Teach & Play” to enhance the repeatability of massage and the efficient trajectory planning.

並列關鍵字

Torque control ； force reflective compensator ； gravity compensator ； impedance control ； adaptive ； Force Counterbalance Control

參考文獻

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