h bridge and servos
04-01-2009, 06:25 AM
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h bridge and servos
In this link [link]http://www.fieroaddiction.com/servo.html[/link] he uses a tecel d100 and references a d200 but that web site is not very functional. Does any one know about these boards or is that company now defunct. Looking at all possibilities here.
Drewcrew6
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04-02-2009, 12:33 AM
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RE: h bridge and servos
Very intersting read. I only read half of it, but I will definitely read the rest of it tomorrow.
As for such an electrinics arrangement, are not pretty much all of today's servos made this way? (I'm not an elctronics expert)
As for such an electrinics arrangement, are not pretty much all of today's servos made this way? (I'm not an elctronics expert)
04-02-2009, 02:25 AM
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RE: h bridge and servos
mmm i tryed accessing that page too but got a "access denied" prompt.........
they mustnt be offering that board anymore.... shame they were good boards
ive allllmost got my own circuit to work.... so far its working but hasnt been tested for durability but it isnt blowing mosfets like it was........and is pulling harder than the d-200 boards were.....
i know i was meant to have it finished ages ago but ive been too buzy
and yes pretty much all servos work like this....
a servo driver- which turns radio signals into electrical pulses to control speed,direction
a feedback pot- to tell the driver what posistion its is in
an Hbridge- uses the pulses to drive heavy loads to the motor
a motor- thur a gearbox to turn the servo horn (and feedback pot)
all we're trying to do is to make another hbridge that can handle HEAPS of current to drive a bigger motor......
they mustnt be offering that board anymore.... shame they were good boards
ive allllmost got my own circuit to work.... so far its working but hasnt been tested for durability but it isnt blowing mosfets like it was........and is pulling harder than the d-200 boards were.....
i know i was meant to have it finished ages ago but ive been too buzy
and yes pretty much all servos work like this....
a servo driver- which turns radio signals into electrical pulses to control speed,direction
a feedback pot- to tell the driver what posistion its is in
an Hbridge- uses the pulses to drive heavy loads to the motor
a motor- thur a gearbox to turn the servo horn (and feedback pot)
all we're trying to do is to make another hbridge that can handle HEAPS of current to drive a bigger motor......
04-03-2009, 06:51 AM
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RE: h bridge and servos
Hey Mad
What is the circuit you are using? FET or transistor. What # on em. Or better yet you got a schematic?
I have about 10 different schematics and all have a slight variance. But that is based on components. Are you using a bought servo or did you do your own controller and everything. I am planning on using a modified bought servo to drive my h-bridge. My biggest concern right now is shootthrough of my circuit. Not sure if a bought servo will have enough delay in it to prevent that.
Drewcrew6
What is the circuit you are using? FET or transistor. What # on em. Or better yet you got a schematic?
I have about 10 different schematics and all have a slight variance. But that is based on components. Are you using a bought servo or did you do your own controller and everything. I am planning on using a modified bought servo to drive my h-bridge. My biggest concern right now is shootthrough of my circuit. Not sure if a bought servo will have enough delay in it to prevent that.
Drewcrew6
04-03-2009, 07:36 PM
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RE: h bridge and servos
hey drew im using fets...
a buddy and i have slightly modified a schem to suit what we are doing... honestly once its all working well i WILL submit a schem.. just not now, i dont want to post a circuit which has a fault we didnt see
whilst testing all the schems on the net, we found most of them worked perfectly on 6 , 7.2 and 9volts..... but as soon as you connect 12 volts, "pop"
i found a brought servo im using now is a key part of it working... its a digital hitec board... being digital there is no logical way both sides of the bridge can be on at the same time...
and it has the ability to "tune" it self to the motor you use so it "may" stop shoot through.... is there anyway you can adjust the deadzone on your driver??
a buddy and i have slightly modified a schem to suit what we are doing... honestly once its all working well i WILL submit a schem.. just not now, i dont want to post a circuit which has a fault we didnt see
whilst testing all the schems on the net, we found most of them worked perfectly on 6 , 7.2 and 9volts..... but as soon as you connect 12 volts, "pop"
i found a brought servo im using now is a key part of it working... its a digital hitec board... being digital there is no logical way both sides of the bridge can be on at the same time...
and it has the ability to "tune" it self to the motor you use so it "may" stop shoot through.... is there anyway you can adjust the deadzone on your driver??
04-04-2009, 05:59 AM
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RE: h bridge and servos
Hey Mad
No way to adjust "deadzone" Using a bought servo and modding it to get the h bridge signals. I keep looking at premade boards but I am not happy that none will interface directly to a modded servo or directly to a reciever. Even the bought hbridge chips won't. I figured at this point there would be someone that has close to a 1 chip solution.
What kind / size motor are you running? I do plan on 12volt for mine. Also what is the on/off time for your fet's as that is where my biggest concern with shootthrough is.
When you are ready to submit let me know I just might be the first "test subject".
Drewcrew6
No way to adjust "deadzone" Using a bought servo and modding it to get the h bridge signals. I keep looking at premade boards but I am not happy that none will interface directly to a modded servo or directly to a reciever. Even the bought hbridge chips won't. I figured at this point there would be someone that has close to a 1 chip solution.
What kind / size motor are you running? I do plan on 12volt for mine. Also what is the on/off time for your fet's as that is where my biggest concern with shootthrough is.
When you are ready to submit let me know I just might be the first "test subject".
Drewcrew6
