Signal follower robot with obstacle avoidance and fuzzy logic

  1. I have problem in building my mini-project as stated in the topic.I am actually confused how the robot will follow a signal like micro wave or radio wave, this kind of wave just spreads and the robot will get confused where to go.I just want opinion what shall i do that the robot will come to the station from where signal is being transmitted.
    Does sonar signal work for it.
  2. jcsd
  3. berkeman

    Staff: Mentor

    Welcome to the PF.

    Do you get to pick the signal that you want to follow, or is it already given by the project definition? You mention microwaves, radio waves and ultrasound. What exactly is the project definition? Can you post the exact text?
  4. I don't know know much about this stuff but I know the antenna you use to receive the signal will have to be "directional" rather than "omnidirectional" so that the power it receives will be strongest when the antenna is facing in the direction of the oncoming signal and weakest when facing away.

    Your robot can spin in place to determine which direction it should be going and then move. It will need to spin in place every so often to make sure it is on the correct path to the signal source, or you could implement PID control to travel toward the source more smoothly.
  5. In regards to following Radio/microwave. We do this all the time in radio repairs. Using a spectrum analyzer and a directional antena. We sweep the area with the directional antenna and look for the highest DB value. taking the measure from several points one can triangulate the position of the originating signal. the key is the signal strength whether your measuring it in dbm or in watts. Keep in mind the radio/microwave signal must be one that conforms with signal regulations. After all you don't want to use a frequency that will cause interferance with other radio's garage door openers etc.

    The fuzzy logic portion would be incorperated in the PID controls and would be simply a matter of how often you wish to re-track the strongest signal strength. Keep in mind all the above mentioned Radio microwave etc can reflect off nearby objects which can throw off the direction IE a reflected signal from a building etc may be stronger than the source signal.
  6. You might look into RF ID tags used in shipping applications. They utilize 3 or more RF antenna in a room that triangluate the source RF Id tags to triangulate position. They also have shipping robots that follow predetermined (RF tracks to follow). Similar tecks may provide you the tools you need with modification.

    edit: something similar to this method may also work for you.
    Last edited: Jan 22, 2013
  7. it is not specified that we have to use the radio or micro wave. I am just confused about which signal or wave to use.
  8. berkeman

    Staff: Mentor

    Please post the exact text of the project statement, or I will lock this thread. You are being way too vague, and this borders on wasting our time.
  9. @berkeman I am sorry for not giving the exact topic of my mini project. Actually i am new in the physicsforum. I am suppose to submit mini project as an electronic project and its free to choose your own project. So, i have decided to make a robot(car) which has following characteristics:
    1)Signal Following application: It will move towards the transmitter.
    2)Obstacle avoidance: If any objects come in front, it just change its direction and again move towards the signal
    3)And i am using a fuzzy logic to control the speed of the motor.

    I had a doubt as i explained earlier that how actually can a robot detect the direction of the signal, radio wave and micro wave spreads and the intensity is not essential that is high for the direction it is coming. Many suggested me to use, directional antenna and PID for the signal following characteristics. I am thinking of SONAR system. It would be a great help if you suggest me about what to do exactly in this transmission and reception of signal with direction detection.
  10. berkeman

    Staff: Mentor

    Thank you for more clarification. It still sounds like you are choosing a more ambitious project than you can do on your own with your current level of knowledge and experience. We will not do your project for you here. That's part of the PF rules and the theme of why we are here.

    Can you explain more about what fuzzy logic is, and when it is appropriate to use it? That would help us to understand your level of training so far and whether you should make that a design goal for your project.

    Can you explain your experience so far with RF technology, and with spatial diversity in antenna systems to help with RF direction finding? Alternately, you could tell us about your experience with the directional antennas that were mentioned earlier in the thread.

    What reading have you done for this project so far? If you can provide links to websites and articles that you have read for this project, that would help us to help you...
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