無外力感測之順應性機械臂控制

本研究目標在實踐無外力感測的順應性機械臂控制理論。一般順應控制需要外力感測器量測作用於機器上的外力並加以控制，優點是外力可知，缺點是價格昂貴。本研究使用加速規與編碼器作為回傳值，並藉由改變系統質量(加速度)-阻尼(速度)特性，增大外力(干擾)對系統運動(位移)的影響，達到順應控制的目的。加速規的好處是反應等效於作用的外力，但價格便宜，可大量採用。缺點是加速度量測值受重力、量測偏移量、系統運動等因素影響，訊號需要經過處理才能代表外力造成之加速度。本研究的次要目標是將順應控制與定位控制結合。定位控制常應用於重複性的工作，同時機器可以提供強大的驅動力，執行搬運重物到定位有相當好的性能。但定位控制的缺點是發生碰撞時，對環境與人會造成很大的傷害。因此順應控制，可以彌補此缺點。順應控制的目的是藉由控制，增大外力(干擾)對系統運動(位移)的影響，此目的與定位控制正好相反。所以碰撞發生時，放大的外力會防止機器造成破壞。定位控制方式使用RST設計理論。並利用加速度信號，判別控制器的切換時機。為驗證控制理論的正確性，我們建立一單自由度的手臂系統，作為控制的實驗平台。

關鍵字

無外力感測器；加速度；順應控制；定位控制

並列摘要

The primary goal of this research is to implement compliance control for robot arm without force sensor. A traditional compliance control need force sensor to detect the force that human or environment applied to manipulator. Its advantage is that we can know the external force exactly. But force sensor is very expensive. At our work, we use accelerometer and encoder to replace force sensor. By changing the mass(acceleration) and damping(velocity) character of a system, we can accomplish the compliance effect. The response of the accelerometer is also an indication of the force and the cost is low. But accelerometer has some problems of gravity, bias and motion of system. We will deal with those problems. The secondary goal is to combine position and compliance control by switching control mode. Position control can provide very high driving force and execute repetition task. But a position controlled manipulator impacts with human or environment, it may cause severe damage to human and environment. To overcome the drawback of position control, we introduce compliance control. A manipulator with compliance control is sensitive to external disturbance. It can reduce damage of human and environment during the collision. We use RST method to design position control. And we use acceleration signal to decide when to switch. We establish a single degree of freedom arm system to verify the control result.

並列關鍵字

force sensor-less ； acceleration ； compliance control ； position control

參考文獻

[ 1 ]. T. Morita and S. Sugano, “Development and evaluation of seven-D.O.F. MIA ARM,” IEEE International Conference on Robotics and Automation 1, pp. 462-467, 1997

[ 2 ]. C.J. Walsh, K. Endo, H.. Herr “A quasi-passive leg exoskeleton for load-carrying”, International Journal of Humanoid Robotics 4 (3), pp. 487-506, 2007

[ 3 ]. L.M. Aksman, “Force estimation based compliance control of harmonically driven manipulators ,” IEEE International Conference on Robotics and Automation, no. 4209744, pp. 4208-4213, 2006

[ 4 ]. R. Steger and H. Kazerooni, “Control scheme and networked control architecture for the Berkeley lower extremity exoskeleton (BLEEX),” IEEE International Conference on Robotics and Automation, no. 1642232, pp. 3469-3476, 2006

[ 5 ]. S. Hara and Y. Yamada, “Positioning of a cart by means of a smooth switching from servo access control to impedance control (realization of force sensorless control), “ Transactions of the Japan Society of Mechanical Engineers, Part C 73 (6), pp. 1618-1624, 2007

國際替代計量

無外力感測之順應性機械臂控制

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