affine visual servoing directly at the control level。 This is obtained without losing the advantages of the image-based control formulation, since we show that all control parameters can be estimated in the im-age plane without requiring camera calibration。 An-other important contribution arises from using non-linear control theory [12,19] to synthesize a control law ensuring global asymptotic stability using the Lya-punov direct method。 We also show that the control law fulfills robustness requirements, since in the pres-ence of bounded modeling and measurement uncer-tainties the tracking error is also bounded。

The paper is organized as follows。 In Section 2, visual modeling issues are addressed。 In Section 3。1 we derive a state space representation of robot camera–object interaction; in Section 3。2, the control system is synthesized, and stability and robustness analysis are carried out; in Section 3。3, it is shown how to estimate 3D state variables from image plane measurements。 Section 4。1 presents results of simula-tions, while experimental results with an eye-in-hand robotic system are presented in Section 4。2。 Finally, in Section 5 the major contribution of the paper is summarized and future work is outlined。

2。 Models and measurements

Assume that the visible object's surface is a smooth manifold of equation 。x; y/ D z in terms of the camera frame hci D fic ; j c ; kc g。 The region of the visible surface is mapped into a patch & of the image plane in which visual analysis is carried out。 Let c Pc D [xc ; yc ; zc ]T be the point belonging to the

Fig。 2。 Ambiguity of weak perspective projection。

visible surface whose projection in the image plane sentation of orientation commonly used in computer

is the centroid of & 。 We consider a local approxima- vision [6]。

tion ofaround c Pc , resulting in the tangent plane Eq。 (3) provides two different solutions for   (and

equation: '), which differ by   。 This results in a pose ambigu-论文网

。x; y/   px C qy C c; (1) ity which is typical of any perspective linearization:

there are two distinct object poses sharing the same

where p  D  。@  。x; y/=@ x/jxc ;yc , q  D 。@  。x; y/= visual appearance [6]。 In the case of weak perspec-

tive, such ambiguity can be written as T 。 ;  ;  ; '/ D

@y/ xc ;yc , and c D 。xc ; yc / pxc qyc 。 The plane

j T 。 ;  C  ; ; ' C / (see also Fig。 2)。 Given two ob-

coefficients determine, up to a degree of freedom, the 1 2 object point, and

relative pose between the camera and the visible sur- ject views  p g and fp g of the same

上一篇:薄壁矩形混凝土填充管(RCFT)柱英文文献和中文翻译
下一篇:气动系统中的冷凝英文文献和中文翻译

超精密自由抛光的混合机...

旋转式伺服电机的柔性电...

ZigBee-RFID混合网络的节电英文文献和中文翻译

模糊PLC系统的伺服机构英文文献和中文翻译

人工神经网络的电液比例...

H∞滤波器视觉伺服系统英文文献和中文翻译

机器视觉维护检测与跟踪...

基于Joomla平台的计算机学院网站设计与开发

浅论职工思想政治工作茬...

上海居民的社会参与研究

浅谈高校行政管理人员的...

STC89C52单片机NRF24L01的无线病房呼叫系统设计

酵母菌发酵生产天然香料...

AES算法GPU协处理下分组加...

压疮高危人群的标准化中...

提高教育质量,构建大學生...

从政策角度谈黑龙江對俄...