Arsip Blog

problem with visual servoing

So I met this girl, Mawadya. I hate facebook for showing me her account and offering me to add her as friend. I don’t know how statistic works in real life. But at least I have some experiences relate to this case.

Ok let’s forget this new student first. I have a more serious problem right here. I have signed to work on some kinda final project on Visual Servoing, for precise Image Based Visual servoing. A semester is left; it means I have at least six months to accomplish this final project. And what happen today is that I don’t have any access to the lab yet. I can’t completely touch the plant to start the research and neither my team mate.

This visual servoing is dealing with closed loop control system in which the feedback signal is represented by visual data, so we use a typical video camera as the measurement instrument. Perhaps you don’t agree with my poor explanation, but it’s ok; all I want is your help maybe you have alotta experiences in this field.

Image based visual servoing is related to the visual sevoing in 2D space. The other one is Position Based visual servoing which is related to 3D space working area.

Here is the common problem comes with this visual servoing. We are to design a control system of a planar robot with some degrees of freedom or maybe a typical Cartesian robot in order to pick and place an object in a bounded area or space. This is not the only problem of course. Generally visual servoing always relates its work with robotic closed loop control system.

My final project is dealing with a Mitsubishi PLC controlled Cartesian robot. I was aiming to mount a video camera on its hand and the mission of the robot is to track a certain object position. The object is of course captured first by the camera and then the camera will lead the robot hand to find that object.

This is actually just like how an eye robot works. A typical pan tilt camera that tracks a determined object movement.  I found lots of videos on this project. They look really easy to realize, but in fact its not!! Well the problem arises when the plant you work with comes in different size and structure. I mean it may come up with the same name “cartesian robot” but a really different structure of components.

Well at least I haven’t found any problem with the algorithm of image processing either the control system. It always easier to build a complete algorithm with any kinda programming language you love than accomplish the electronic devices.

In fact I need to make sure that I can communicate my PC as the image processor with the input of the PLC. I have really little experience work with PLC, or perhaps this is my first time. Here I used GX developer to upload ladder program to the PLC. But I don’t know if I can realtime-communicate the PC with PLC.

One more thing; here I use DSpack of Borland Delphi 7 to process the image. I don’t know yet how output the signal from PC and input it to PLC. Can I use that GXdeveloper to input the control signal to the PLC?