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  • Author Author: mohanedessam
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Book Carrying Robot #8 Trials and future development

mohanedessam

I described all aspects of my software and hardware design in my previous post.

 

in this post I will just show some of my trials, comment on them, and suggest possible future development.

the path is made to be a bit noisy (not so straight) to show that the robot is still able to accommodate for some path glitches.

 

the Robot was able to follow its miniaturized path correctly for some trials:

 

 

 

 


However, other trials had some errors:

 

 

 

Of course the design has a lot of possible enhancements and room for development:

1- replacing the Relay circuits with motor drivers to decrease the response time

2- using Raspberry PI PWM pin, and software PWM to control the motor speeds independently from each other, this allows modification of movement direction using the two motors differential speeds; this gives much more accuracy and much better response time compared to the ON/OFF approach. 

3- make use of MATLAB control systems to control the motors speeds and the robot direction for better response and accuracy; such as PID controllers.

4- enhance the main function code processing time by:

     1- using mex functions (C-language)

     2- vectorization of the code

     3- use more toolbox functions as opposed to written scripts

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  • Nice project.

     

    I noticed of it yesterday but until this morning there was no way to see the videos image

     

    I have an hypothesis about the errors. Maybe that the image processing the path works faster (simplified cases of the algorithm) when there is a straight line to follow instead of a curve. As the path start coming more complex the processing part for movements feedback comes slow generating a sort of progressive derivative behaviour. Maybe the solution is to work with a variable speed, based on the complexity of the algorithm ?

     

    Enrico

  • in reply to balearicdynamics

    exactly as you said, it's a common problem caused by the delay in processing and movement response, because you can see that the robot responds to the images a bit later; so as you said we should try to increase the speed of the image processing part, and also increase the motor response by continuously changing the motor speeds to avoid this overshoot that we see in the errors; of course if we can implement a PID or PI controller we can improve a lot but this still needs a good manipulated variable (motor speeds) which I don't currently control.

     

    for the straight parts of the path I have increased the tolerance of the image processing response, so it won't respond to small variations in the path position, however if I decrease the tolerance it will still have this oscillatory behaviour noticed in the curves.

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  • in reply to balearicdynamics

    exactly as you said, it's a common problem caused by the delay in processing and movement response, because you can see that the robot responds to the images a bit later; so as you said we should try to increase the speed of the image processing part, and also increase the motor response by continuously changing the motor speeds to avoid this overshoot that we see in the errors; of course if we can implement a PID or PI controller we can improve a lot but this still needs a good manipulated variable (motor speeds) which I don't currently control.

     

    for the straight parts of the path I have increased the tolerance of the image processing response, so it won't respond to small variations in the path position, however if I decrease the tolerance it will still have this oscillatory behaviour noticed in the curves.

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