Visual Servoing

Visual Servoing, also known as Vision Based Robot Control and abbreviated VS, is a technique which uses feedback information extracted from a vision sensor to control the motion of a robot. One of the earliest papers that talks about visual servoing was from the SRI International LabsAgin, G.J., "Real Time Control of a Robot with a Mobile Camera". Technical Note 179, SRI International, Feb. 1979.] . The most noted tutorial on Visual Servoing was published in 1996 by A. Hutchinson, G. D. Hager, and P. I. CorkeS. A. Hutchinson, G. D. Hager, and P. I. Corke. [http://citeseer.ist.psu.edu/76215.html A tutorial on visual servo control.] IEEE Trans. Robot. Automat., 12(5):651--670, Oct. 1996.] .

Visual Servoing Methodology

Visual Servoing techniques are broadly classified into the following types

*Image Based (IBVS)
*Position Based (PBVS)
*Hybrid Approach

IBVS is also referred to as a feature based technique. This is because the VS algorithm uses features extracted from the image to directly provide a command to the robot. Typically, all the information extracted, from the image features, and used in control happens in 2D. In most cases it is in the image space (image co-ordinates). A point to be noted is that the robot may still move in 3D.

PBVS is sometimes referred to as Pose Based VS and is a model based technique. This due to the fact that the pose of the object of interest is estimated with respect to the camera and then a command is issued to the robot controller, which in turn controls the robot. In this case the image features are extracted as well. But the feature information is used to estimated 3D information (pose of the object in Cartesian space). Hence servoing in 3D.

Hybrid approaches use some combination of the 2D and 3D servoing. There have been a few different approaches to hybrid servoing
* 2-1/2-D Servoing
* Motion Partition Based
* Partitioned DOF Based

ee also

*Robotics
*Robot
*Computer Vision
*Machine Vision
*Robot control

References

Relevant Articles

Chaumette, S. Hutchinson. [http://www.irisa.fr/lagadic/publi/publi/Chaumette06a-eng.html Visual Servo Control, Part I: Basic Approaches.] IEEE Robotics and Automation Magazine, 13(4):82-90, December 2006.

Chaumette, S. Hutchinson. [http://www.irisa.fr/lagadic/publi/publi/Chaumette07a-eng.html Visual Servo Control, Part II: Advanced Approaches.] IEEE Robotics and Automation Magazine, 14(1):109-118, March 2007.

External links

* [http://www.cat.csiro.au/ict/staff/pic/vservo.htm CSIRO Visual Servoing Homepage] .
* [http://robotics.engr.wisc.edu/ UW Madison Robotics and Intelligent Systems Homepage] .