Controlling motor/need of an encored?

[simasa]

I have a simple problem related to control of a dc motor

I am planned to develop a system consist of a motor and a camera. the camera monitors and controls the motor output motion. The camera keeps sending a position signal to controller until motor is at desired position (and goes on).
Now I am doing position confirmation of motor by external image processing. There is also an adjacent encored with the motor that can give position confirmation information. So now I will have 2 position control signal for the motor.

How 2 readings should be of a same parameter should be handled?

Should the encored connection be disconnected?

Can I achieve some additional benefit having two readings of a same parameter (of course there will not be completely identical)?

Could there is come control strategy like cascade control/switching control loops/optimization that may be considered to achieve something (optimize accuracy)?

I will be thankful for any suggestion
Simasa

 

[simasa]

there is typing mistake
the write word is ---- Encoder

 

[itsmoked]

The word is encoder.

Typically you would have the camera generate a desired position that it wants the camera to go to. Then your control algorithm would act to move the camera smoothly to this new position 'fed back' via the camera's encoder.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[simasa]

thanks for the reply
The camera also moves. Because of this movement, the image processing is able to control motor to incorporate it with the motion of camera.
Now I am interested to know, how about motors’s encoder ?
is there any function now left for motors’s encoder? Should I switch its connection off ? or can I use it in some intelligent for some betterment.

 

[itsmoked]

You do not understand my answer?

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[simasa]

yes, i did not understand completely, if you could please write in some more details. I will be thankful
simasa

 

[guiglielmo]

Dear Simasa,
You will have two different response times for the position measurement from the two sensors. They are delayed in time one from the other. I would use the fastest signal of them two for a faster response of the control system.
You could use the second one as a backup for operational reliability or safety, but the problem now if one fails, how would you know which is the failed one? you should have a third one and a voting system in order to have a 1 against 2 voting system. I wouldn't recommend duplicating unless there is a functional justification to use it.
Good luck with your circuit,
Guiglielmo

 

[ozmosis]

Interesting article:

http://drives.co.uk/fullstory.asp?id=2150

that may be of use.

 

[itsmoked]

simasa; To control the pointing of ANYTHING you usually want a system where you tell it go to X and it can go to X by stepping so many times or better by going there while having something that provides feedback. (An encoder!) So first you should set up your camera to go to some coordinate, you ask it to, using its own encoder and motion motors.

Once that works well, an smoothly, then you can use the camera's position command to tell your already working camera moving system WHERE to go.

This way you break apart your tasks and the system to allow you to get each part running well and as best it can then combining them.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com