Servo Compact Design Problems!!!

[Dominator_Legen]

Hello,

The Links Of The Image That Descrype The Problem, Please See It To Understand My Problem
http://www50.brinkster.com/dominatorii/


I'm not in FIRST competition, And I'm new in robotics, So please be patient with
me, and use a simple words, cause my English is not so good, Thanks.

The Problem:
I'm building my graduate project it's a rover robot that move on 6 wheels as
shown on the above figure, this figure is a basic design for my BlackBot,
as you can see, Wheels number 1,2 and 3 are connected together with Track-1,
while Wheels number 4,5 and 6 are connected together with Track-2,

Each wheels from 6 wheels are connected to its servo motors, So we have 6
Servo here,

Now assume that we want to compact the design of this robot, can we
connect the servo number 1,2 and 3 together in parallel connection, Called Con-1
And connect servo number 4,5 and 6 together in parallel connection, Called Con-2

I think its ok, if we connect the first 3 servo together in parallel so the volt
is constant but the current will distributed on each servo,
For example: if we connect the 3 servo in parallel, and apply 5 volt and 300 mA
to this connection, So each servo will take 5 volt and 100 mA, Cause volt is
constant and the current is variable.

The question is:- Is there a way (Circuit) That deliver to each servo a 5 volt and 300 mA.

If you see the above figure I supposed that I have an 2 amplification circuit that will
amplification the power and signal that came from the main board and distribute
it to each servo, so each servo take 5 volt and 300 mA,

--------

Please if you can help me on design, (I mean a PCB) or any other things that help
me, making it, this will be appreciated, also I need confirmation if this method have disadvantage (Such as I will not control the speed), cause the servos in
any ways will take 300 mA, There are something I don't get it, Can I control the speed of the servo (make it slow down or move fast), and how is this done,
I read many notes about modification of servo and how its work but I'm didn't
get it, So please if any body, can explain it to me more simply, (The reason my English is not so good), This will be appreciated, and please the confirmation on this design and its disadvantage

[Dominator_Legen]

Please Any Help

[Rickertsen2]

You shouldn't need any fancy circuitry. You should be able to connect all 3 servos in parallel and it should work

[Dominator_Legen]

The current will divide (if i apply 300 mA) to connection, then every one take, only 100 mA, So How its going to work.

[SteveO]

I would like to help you, but I need to know more about what you are working with. Obviously you are using the servos to drive your robot, what are you using as a power supply? Also, in the picture you have a "main board," what does this main board consist of?

[Dominator_Legen]

I'm didn't specify this information cause i'm didn't set its spicification until now, but i think this is not the problem (assume a convenient motherboard and battry), Is this connection logic, is there drawback(limited speed) or somthing,

I know that must be specification But i'm working in this part right now, So please help me on it, Help me to decide if this optimization is correct and what i need, and also, There is somthing i didn't get it, (I think all the mainboard are the same, they diff. in its capapilites, # of I/O, I didn't know if they diff on the volt applyed to the servos? Its Diff?),

The main board will recive a signal from a tranceiver then it will activate a function inside the chip,(According to the signal coming from operator through the transceiver), the power supply used is a battry, (i'm working on this project and i'm new so i'm didn't decide until now what is the requred volt),

But i asked my question, cause i'm thing that if we assume the ideal power supply and mainboard, What is the drawback of this design, what i need to build it, please try to imagin what i'm need,

Please help me out,

Thanks

[SteveO]

I think it will work, if you are worried about the current drop can you use a larger power source? If you are getting your servo power source from your motherboard I don't think you will have a problem, but it depends on the motherboard. I would decide on a power source and motherboard to use, then think about this problem. Have you started building anything?

[Dominator_Legen]

Here is my robot design,
It's move on 6 wheels, so we have 6 servo, and 2 another servo to mount camera, and another 2 servo to mount the gun, or the laser-beam, so we have until now 10 or 11 servo,

And we have a camera, mic, GPS, Compass and Transcever,

This is the components, i counted now, so assume if the total current requred to keep the above device work good, is 15 or 20 Am, and the Power supply deliver 25 or 30 Am, So i think there is no problem, But if the the Battry, can deliver more than 14 or 16 Am, So we need to amplificate the current goining to each device, But I'm now talking about these servos (The 6),
I think that The power supply will connected to mother and the mother distribute it,

I'm Didn't Start yet i'm collecting info. right now, And think...??

[Dominator_Legen]

Any Suggestion Please.

[Andy A.]

Dom-

A solution to this problem could be easy, or could be difficult. We can not be very helpful with out more information from you. I would like to know more about the servos you plan on using to power the wheels. Do you have a website that provides information about them?

There may be a simple misunderstanding. A servo to me is a small device, containing an electric motor, gear reduction, and some electronics that allows it to move the motor to a position and maintain that position. They are used in making remote controlled model airplanes and cars. Usually they can only rotate a fixed amount, maybe 300 degrees. It sounds like your servos can rotate continually. This makes me think that your servo is different then what I consider a servo. You may mean an electric motor.

Does your servo look like this? http://www2.towerhobbies.com/cgi-bin...&I=LXVW07&P=ML

This is important because making a simple electric motor move and making a servo move are very different.

Also, you're English is very good. It is not an easy language, and you manage to communicate your self better then some English speakers do! Keep up!

-Andy A.

[Dominator_Legen]

I sound a problem here, Do you mean that the servo can't be used to move a rover to any distance I want,

If the servo isn't the correct choice, then what is best motor that I may used to deliver to me fast and strong rover, also I hared that the servo can be modified to move continually, so how you said that its maximum degree is 300,
Please if I'm wrong correct my info,

Thanks, I know that servo is small electronic device, BUT the thing that I don't got it, is the time frame that I apply to servo to work!!!

I sawed a lot of robotics project (rovers) that use servo, so how they make it continually,

I Think That There Are Something Called Servo Modification That Allow Servo TO Operate Continually (Did you here about it), Or The Servo After Modification Operate 300 Degree,

you make me feel that there are problem using servo, So Please Tell me if I'm wrong or what is the problem

[thoughtful]

Here is a link that tells you how to modify a servo for continuous rotation.
(i have never tried it myself)

http://www.acroname.com/robotics/inf...ontinuous.html

[sanddrag]

Sorry I don't have time to be of more assistance but these links may help you out.

Modifying servos to rotate continuously:
http://www.seattlerobotics.org/guide/servohack.html

Lots of (bigger) robot parts:
www.robotmarketplace.com

Good place to buy servos (smaller ones and bigger ones too):
www.towerhobbies.com

Lots of good small robotics parts and kits:
http://www.parallax.com

[Dominator_Legen]

Thanks,

But i already know how to modify the servo, i have 5 or 8 tutorial on servo modification, My question, Is the servo are correct choice in my project?

If true then (What is the drawback of the above design? and how can i build it?)
Else (What is choice here? (The Motor that will work.))

Thanks,

[SteveO]

I think the servo will work for you. I can't say if it is the best choice because I don't know the specifications of the servo you are using and the size of your robot. Instead of using the modified servos you could use DC motors, which I think for your purposes will be pretty much the same thing.

The drawback to your design is that turning will be difficult, but if your motors are powerful enough it should not be too big of a problem. There may be an issue depending on your power supply, if you have enough for the motors. Other than that, I'm fairly sure you will be able to accomplish what you have in mind using your current setup.