Steering Circuit

Discussion in 'The Projects Forum' started by Jure George, May 24, 2010.

  1. Jure George

    Thread Starter Active Member

    Dec 28, 2008
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    Hello to All

    I am looking for a circuit that can be built by anyone using standard I.C and Transistors, resistors,capacitors etc.

    I am involved with R.C Submarines, 75mHz, FM. The submarine runs off of 6v to a max. of 12v main battery power.

    I would like to build a steering circuit since my sub has no rudder. It has Two small thruster motors,on on each side, 1A max. current draw. I would like this circuit to be plugged into One channel of the receiver and get its power from the receiver. Since the receiver works off of the 6v main battery, i suspect thats what the receiver sends out to a servo, if that was on the rudder channel instead of this future steering circuit.

    I would like the steering to be " proportional " when you want to turn right, the right motor runs in one direction and the left motor runs in the opposite direction and with the increase demand for a harder turn then the motor would run faster in that turn and the other would run faster in the opposite direction to help make the turn go faster. when going strait then both steering motors face forward and are off. The main rear motor is for forward/Reverse.

    I hope that someone can give me a working circuit that will do this as well remember please, its going into a small submarine so circuit board size is important. Also can this been done without its own speed control and I don`t link mechanical relays, solid state relays, I could live with.

    Thanks In Advance to All for Your Time and Help.

    George
     
  2. SgtWookie

    Expert

    Jul 17, 2007
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    Hello again George.

    I know it's difficult getting used to the protocols on new boards. Trust me, I was new on here a few years back.

    If I understand you correctly from your other thread that was posted here:
    http://forum.allaboutcircuits.com/showthread.php?t=38496
    you have a multichannel remote control, of which you wish to dedicate only one of them to control the motors.

    If I understand you correctly, the input signal would be of the type of a typical servomotor; which is a signal that varies from nearly 0% PWM to nearly 100% PWM at a 20mS interval.

    If anything I've said so far is not correct, you need to speak up.

    If I am not mistaken, you also have a throttle control. Is that correct?

    If so, the throttle control needs to be somehow integrated into the rudder control, as one will affect the other.

    I hope that you appreciate that this is not a simple task that you are asking about, and that a decent solution may be several days in the making.
     
  3. Jure George

    Thread Starter Active Member

    Dec 28, 2008
    51
    0
    Hello again

    Yes One channel of the Two channel transmitter is for the Rudder ( steering ). I hope to use a circuit on that channel. That will control Two small thrust motors. As the steering demand is activated via the transmitter stick Left or Right, then through the receiver and the circuit plugged into that channel of the receiver, the appropriate thrust motor operates in the proper direction and the other thrust motor operates in the opposite direction. The speed of the motors depends on how hard of a turn is called for. Slow turn, less power to the thrusters, hard turn and max. power to the thrusters etc.

    The other channel would be the Forward / Reverse speed controlling the motor. Just like on a surface boat, one channel controls the drive motor forward/reverse and the other channel the rudder( steering ) but in my case, Two thruster motors provide the steering.

    The receiver is a standard FM 75mHz Transmitter/receiver set.The main power is either 6v upto 12v max. And the thrust motors would draw a 1A Max. each. I am not sure as to the actual signal specs. so I will defer to your knowledge on that field. I understand that this circuit will take time to develop and I appreciate your willingness to help me.

    Thanks Again for your Help, I will check in here nightly to see if there is any progress or further questions of me.

    George
     
    Last edited: May 24, 2010
  4. SgtWookie

    Expert

    Jul 17, 2007
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    You are not answering my question.

    You say that you have a rudder (steering) input, but say nothing about the throttle control.

    Is the throttle running wide open (fast as it can go) all of the time? Or do you have control over the throttle?
     
  5. Jure George

    Thread Starter Active Member

    Dec 28, 2008
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    0
    Sorry, Yes I have control over the throttle, from stop to full speed as I move the transmitter stick from centre forward then from centre downward I have reverse just not as fast as forward of course.

    George
     
  6. SgtWookie

    Expert

    Jul 17, 2007
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    OK.
    Did you get the circuit working that I posted in the other thread yet?

    There is no point in continuing until you get that one working.
     
  7. Jure George

    Thread Starter Active Member

    Dec 28, 2008
    51
    0
    Hello again,

    I guess you didn`t read that reply in that post to your question. I ordered parts, b/o waiting for a call to p.u all at one time, about a week for the parts to come. Then will breadboard and test with my futaba radio/receiver and let you know back.

    If all o.k, I have a few subs for that circuit to work on in my fleet. As well as a few on the planning / building list for this new circuit.

    Thanks Again for All Your Help.

    George
     
  8. Markd77

    Senior Member

    Sep 7, 2009
    2,803
    594
    Would a normal ESC (electronic speed control) work? Connect one motor backwards in parallel with the other.
    (You would need to find one with reverse and no fancy features like double tap for reverse).
     
  9. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    An esc might work, as suggested. I was thinking of something similar, since the steering motors are low power and not described in detail. Namely, two servos modified to run continuously with the same null point could be used on one channel for steering power. One servo would have to be reversed is all.

    John
     
  10. Jure George

    Thread Starter Active Member

    Dec 28, 2008
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    Hi

    If a pair of modified servos were used to drive the thrust motors, would the speed of each thrust motor be variable or when activated, are the thrusters at full speed ?

    George
     
  11. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    Whats wrong with the receivers you already have with a speed controller ESC(if it is not already equipped)? The electronics is already done for you in your transmitter/receiver set.. The mechanical linkages can be the hard part. Hook 1 servo up to the receiver to steer and another to the speed controller which is hooked up to the thruster motors.
     
  12. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    I mentioned servos, because of the very low (compared to propulsion) power requirements of the thrusters and your apparent concern over cost. Otherwise, why use just a two channel system? As I understand it, the modified servos would be full on or off, as model servos are not variable speed. The esc, of course, will give you proportional control. However, pulsing full on or off to get what you want done is not that hard. All model RC was like that in early 1950's when I started.

    John
     
  13. Jure George

    Thread Starter Active Member

    Dec 28, 2008
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    Hello All

    I used the Two channel radio as an example. It would be a waist of a channel from a larger Transmitter to use each channel for each servo esc for each thruster plus the main ESC for the main motor driving the sub in Forward / Reverse.

    What I am hopping for is something from one channel that drives both thrusters in the direction of the turn required and to either run the thruster motor slowly for a slow turn OR fast for a hard / fast turn. Since we normally have Two hands, One controls the main motor drive speed and the other the steering.

    Size does matter as well, subs do not have lots or internal room.

    Hope this helps with what I need.

    George
     
  14. Jure George

    Thread Starter Active Member

    Dec 28, 2008
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    Anyone still working on this ?

    George
     
  15. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Apparently not.

    The answer (an esc with one motor reversed) was given a few times. What have you done to test that idea?

    John
     
  16. Jure George

    Thread Starter Active Member

    Dec 28, 2008
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    The one motor reversed with one ESC for the pair is new to me. I am not sure about it. Would the one ESC be able to control the speed of both motors? I don`t want to try and fry the speed control.

    Also someone mentioned converting Servos to run continuously BUT does that mean you would still have control over the speed of the servo OR would it just be at Full speed from the start, varying speed is what I want and I guess I could wire both modified servos with one reversed so that they could both be plugged into the same channel on the receiver IF the modified servo has varying speed control ?

    George
     
  17. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Most aircraft would use two esc's and two channels to allow trimming. The suggestion here was to use just one esc. I suspect it would work. Otherwise, just use two esc's and "Y" then to one channel. That is done all the time and will definitely work.
    That was addressed in post #12. Please read the answers people have suggested before asking the same question again. Some transmitters (e.g., JR9303) do offer a degree of servo speed adjustment, and ways to do that with other drivers or transmitters have been discussed on this Forum before. For all intents, just assume the servo solution would be full on or full off. The servo suggestion was a COST saving measure based on a false assumption that cost mattered to you. But, considering the speed your submarines are traveling (I assume substantially less than 30 knots), full on and full off may not be so bad for positioning.

    John
     
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