• CN：11-2187/TH
• ISSN：0577-6686

›› 2007, Vol. 43 ›› Issue (12): 212-216.

• 论文 •

### 改进的链码特征识别方法及在抽油系统阻尼系数辨识中的应用

1. 西安理工大学机械与精密仪器工程学院;中国地质大学(武汉)机电工程学院
• 发布日期:2007-12-15

### AMELIORATIVE CHARACTERISTIC RECOGNITION METHOD BASED ON MODIFIED CHAIN CODE AND ITS APPLICATION IN DAMPING COEFFICIENTS IDENTIFICATION FOR ROD PUMPING SYSTEM

LIU Baixi;LIU Hongzhao;RAO Jianhua;YUAN Daning

1. School of Mechanical Instrumental Engineering, Xi’an University of Technology Faculty of Electromechanical Engineering, China University of Geosciences
• Published:2007-12-15

Abstract: Aimed at the shortcomings of the eight-directional Freeman chain code method, a new 24-directional chain code is put forward to encode the closed boundary curve of an image. The parametric equation of the closed boundary curve is transformed into Fourier series whose coefficients can be computed according to curve’s chain codes. By means of these coefficients, shape characteristics of the boundary curve are extracted. The Euclidean distance based on shape characteristics is introduced as the measurement of similar degree between two different closed boundary curves. Changing the value of viscous damping coefficient and Coulomb friction coefficient in the simulation program, different simulated dynamometer cards are obtained. Substituting their shape characteristics to the Euclidean distance, respectively, a series of distances are acquired. When the distance is less than the given error, the corresponding values of the damping coefficients in the simulation program are regarded as real damping coefficients of the sucker-rod pumping system of directional well. In the end, an example is given to show the correctness and effectiveness of the presented method.