機械手臂之加速度觀測及其應用

Acceleration Observation for a Robotic Manipulator and Its Application

陸俊瑋(Lu Chun-Wei)

指導教授 ： 呂有勝

國立臺灣師範大學/科技與工程學院/機電工程學系/碩士(2017年)

https://doi.org/10.6345/NTNU202203314

摘要

['本文主旨為雙軸機械手臂加速度的估測，並且使用線性加速度感測器來量測。由於一般在市面上角加速度感測器比較難以取得，因此在實驗中使用線性加速度規。一般常用的線性加速度規通常是電容式與壓電式加速度規兩種。由於MEMS技術的進步使的電容式加速度規變得無所不在，但是與壓電式加速度規相比，電容式加速度規在頻寬與雜訊之間存在很大的衝突，因此限制了它們在高性能運動系統的應用。另一方面，壓電式加速度規在頻寬與雜訊之間有很好的平衡，卻無法量測低頻之加速度訊號。
在本研究中，在具有兩個旋轉關節的雙軸機械手臂之末端安裝兩個壓電式加速度規，並且使用光學編碼器來測量兩個旋轉關節的角度。接著使用角度和壓電式加速度規所量測之線性加速度，估測出兩個旋轉關節的直角座標加速度。
本文實驗平台採用TI TMS320C6713 DSP與Xilinx可程式閘陣列(FPGA)結合而成之控制器硬體核心，以C語言與硬體描述語言(VHDL)作為控制器設計之發展工具。本文實現所提出的加速度觀測器設計方法，並且使用加速度干擾補償器(ADOB)，比較各種加速度訊號對於實驗平台控制性能之影響，由實驗結果可知本方法具有實用性。
']

關鍵字

加速度估測 ； 壓電式加速規 ； 機械手臂 ； 加速度干擾補償器

並列摘要

['This paper considers the estimation of angular accelerations for a two-link robotic manipulator using linear accelerometers. Since angular accelerometers are not commonly available, linear accelerometers are used in this study. Popular linear accelerometers are of capacitive and piezoelectric types. Due to tremendous advance of the MEMS technology, capacitive accelerometers have become more ubiquitous. However, compared with piezoelectric accelerometers, capacitive accelerometers suffer from serious tradeoff between noise and bandwidth, which limits their application to high-performance motion systems. Piezoelectric accelerometers are excellent in terms of noise and bandwidth. However, they are unable to measure low-frequency acceleration.
In this study, two piezoelectric accelerometers are attached to the end-effector of a two-link robotic manipulator with two revolute joints, and optical encoders are used to measure angular positions of the two revolute joints. With the information on the angular positions, accelerations of the revolute joints are then estimated using the linear accelerations provided by the piezoelectric accelerometers. An experimental study is conducted to demonstrate the feasibility of the proposed estimation scheme.
In the experimental system, the control kernel is a DSP/FPGA system, and the C language and the VHDL are utilized as developing tools for the two-link robotic manipulator system. In experiments on tracking control, an acceleration-based disturbance observer (ADOB) is used to evaluate various acceleration observer design methods for performance comparison. Experimental results proved that the observer scheme produces better transient and steady responses than conventional approaches.
']

並列關鍵字

acceleration estimation ； piezoelectric accelerometer ； robotic manipulator ； acceleration-based disturbance observer

參考文獻

[1] 盧世元，機械技術雜誌：機械手臂揮灑出自動化的願景，2009。

[2] R. J. E. Merry, M. J. G. van de Molengraft and M. Steinbuch, Velocity and acceleration estimation for optical incremental encoders, Mechatronics, 20(1) (2010) 20 -26.

[3] S. J. Ovaska and S. Valiviita. Angular acceleration measurement: A review, IEEE Trans. Instrum. Measur, 47(5) (1998) 1211–1217.

[4] 333B50 Accelerometer Datasheet, PCB Piezotronics Inc.

[5] ADXL325 Accelerometer Datasheet, Analog Devices Inc., 2004.