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Closed loop stabilization control - integrator circuit

  1. Feb 27, 2012 #1
    Hello all.

    I have a platform that is controlled by two electric motors (one for elevation, one for rotation). During the application, I would like to have the platform maintain it's current position. I'm imagining a system where you set the position manually, and then press a button that will tell the platform to hold its current position. This is a relatively large platform with large external forces acting on it, so the motors will need to be driven to correct for changes in the platform's position.

    I have an angular rate of rotation sensor (gyro) mounted on the platform. I would like to use this gyro as the feedback sensor for the system. Since the gyro outputs the angular rate of rotation (dθ/dt), if I take the integral of the gyro signal over time, and set the integral to zero, the final position will be equal to the initial position:

    ∫dθ/dt (from 0 to t) = θ(t)-θ(0)
    If ∫dθ/dt=0, θ(t)=θ(0) (Hence, final position equal to initial position)

    This is where I'm hoping some electrical engineers can help out. I seem to remember designing integrator circuits in college, but that was some time ago. Are there components I can use to take the integral of the gyro signal? Is there a way to hold the value of the integral at 0 over time?

    I'm looking for any feedback. This concept seems simple to me, but if it would be difficult to implement I'm open to suggestions of another path to explore. Thanks for any and all feedback!
  2. jcsd
  3. Feb 27, 2012 #2
    Analog integrators can be made using reactive components. It might have been better if you searched the internet for "integrator circuit" before posting.

    As for designing the entire close loop control system, perhaps this would be better accomplished by someone who better understands how to design a control system, especially considering the mass, cost, and potential danger that I associate with your equipment. I think the entire system should be modeled mathematically before implementation.
  4. Feb 27, 2012 #3


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    A proportional–integral–derivative controller (PID controller) may be something to look into. What are your motor specs?
  5. Feb 28, 2012 #4

    jim hardy

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    would just a locking brake do?
  6. Mar 1, 2012 #5
    you have a platform to be fitted with a gyro,and want to control 2 motors to change x-y direction.

    what you need a controller with two individual outputs (suitable for the drive of the motor) it is little tricky - as drives for ordinary DC motor to specilized Variable frequency drives are possible with positiner.

    And the Gyro sensor to be connected to controller as process variable.

    you can make your own P only controller out of opamp with a resitor slider for giving Set point to the inverting input to opamp.and another slider in feedback for gainchanging.

    The output circuit should be a converter to drive the motor.

    But this is ameaturist approach.

    There is a better approach as professinal.but I will tell you more if you give me the details of your existing platform motors and gyro.and your intended project.
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