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I need a help and guide in this case
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Rookie

Joined: Sun Jul 20, 2014 10:14 pm
Posts: 11
I need a help and guide in this case
Hello all ,
I've been working on my two-wheeled mobile robot I've been trying to perfect my obstacle avoidance algorithm which is Artificial Potential Field method . Also i use Arduino Uno kit . The basic concept of the potential field approach is to compute a artificial potential field in which the robot is attracted to the target and repulsed from the obstacles . The artificial potential field is used due to its computational simplicity . the mobile robot applies a force generated by the artificial potential field as the control input to its driving system . the Artificial Potential Field method in its computations depends on the distance between robot and goal or target and the distance between robot and obstacles that effected the robot (which could easily get for ultrasonic senors)

I applied the Artificial potential field method in Matlab environment / simulation and it is done successfully , really what I need in the simulation is to get the current position of mobile robot and position of goal as x , y coordinates (to compute the distance between robot and goal) and the obstacles positions ,

The output of the Artificial potential field is the desired angle to avoid obstacle and reach to the goal , the method give the robot the angle the pointed to the goal then the robot goes toward that angle and if the robot face an obstacle in his way ( got from sensor reading) the Artificial potential field will update the angle to avoid the obstacle and then re-give the robot the angle that pointed to the goal and so on.

The question is how could I apply the Artificial potential field method in real would ? what should I get ? is it easy to do that or it is impossible ?

I had Rover 5 with two normal DC motors and two encoders (incremental rotary encoder) per each wheel .

Any Help or suggestion on the topic will be highly appreciated please.

Wed Aug 06, 2014 9:22 am
Professor

Joined: Sat Aug 31, 2013 9:15 am
Posts: 256
Re: I need a help and guide in this case
I would highly recommend a gyro sensor to help you track robot orientation. That will certainly be a lot easier and more accurate than trying to track orientation with the encoders.

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Wed Aug 06, 2014 9:38 am
Rookie

Joined: Sun Jul 20, 2014 10:14 pm
Posts: 11
Re: I need a help and guide in this case
 BurningLights wrote:I would highly recommend a gyro sensor to help you track robot orientation. That will certainly be a lot easier and more accurate than trying to track orientation with the encoders.

Dear BurningLights many thanks to you
I really appreciated that for you

Dear the case is very simple , but first , there is something to know that I constrained with some limitations that I couldn't overstep them , one of them is that the real world should be exactly as simulation for example in the simulation I consisted that robot started with (0,0) on coordinates x , y axis and I should put the goal point for example (10,20) and feed this point in the Artificial potential field method and then compute distance between robot and goal (so I don’t need any technique to determine the position of goal) and I don’t know if I could applied that.
the second constrain is that I should use the encoders of wheels to determine the current position of mobile robot and its orientation depending on a calculation formula (something like this http://rossum.sourceforge.net/papers/DiffSteer/) even if that will be inaccurate .
I had a Rover 5 with two normal DC motors and two encoders (incremental rotary encoder) per each wheel , each encoder has four wires I don't know how to deal with them yet, and how could I translate the pulses of encoders or how to work out the x.y position of your robot based on the shaft encoder data..
I am still searching for ….

thanks a lot .

Wed Aug 06, 2014 3:23 pm
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