Any H-Bridge Circuit schematics for motor control?

[Guest]

Guys, It took me months and months to find out on the exactly answer for creating the interfaced circuit for DC motor control. I thought Stepper motor would be the solution, but apparently they do cause a few troubles, I could not be able to solve the circuit interface when running EPIC or FS2002. I have went through phone-calling, internet source, and e-mails to many kinds of robotics manufacturer and they seem don't quite get what I am looking for *sign... There are somedays I've been thinking about giving up on what I'm looking for but No, because giving up my hope would have got me becoming sad for not getting something in successful. What I am looking for is interfaced circuit that can control both polarity using DC motor. AND... Finally, I got the answer... when Ralph Robinson replied e mail back to me ,He said I could use H Bridge with 4 NPNs Transistors, Or H-Bridge IC and maybe adding few capacitor for charging or filtering. But he probablly doesnt know any schematics, So Hopefully anyone has any schematic that would drive DC motor in both polarity as it can be used for Autothrottle control, maybe Auto yoke in additional if its not too much trouble... Let me know. I

[Guest MikePowell]

Arthur,Allegro Micro is a company that makes a wide range of power control semiconductors, including H-bridge motor drivers. This spec sheet from them is pretty informative: http://www.allegromicro.com/techpub2/stp/stp98-9.pdf There is also a book that discusses motor drivers that may be of interest to you: Building Robot Drive Trains by Clark and Owings.Also, I just got a snail mail catalog from Electronics Goldmine www.goldmine-elec.com that lists a Dual full-bridge driver with a heat sink for only $1.99. It's an L298. (Their part number G13491) It's on their web site. search for "L298". I haven't used this one but it looks like a possibility.Mikewww.mikesflightdeck.comInfo for simpit builders.

[Guest dirkan]

Hello,why don't you use a simple relay. If you want to control movement of throttle, the motor will need some Amperes. The L293 and L298 are limited to 1.5A an 3A (afaik). A relay is much easier to handle with high current supply.Dirk

[Guest]

Mike, Thank you for the website or any sources on the issue that I've been looking for. You have been helpful :-) Now, I have already found myself a schematic of H Bridge circuit.Dirk. Instead of using relay, I'd much prefer to use L298 with diode, resistor, capacitor, and 5 volts regulator. because I will have it connected up with EPIC output module which can only allow limit up to 2 amps of current flow. Thanks anyways...

[Guest]

Hi Arthur, Just a note: Building discrete H-bridge with transistors or MOSFET's for DC motor control is not that easy. I did a lot of experiments with all kind of H-bridges for my motion platform drive and force feedback power buffer. I needed lots of power, and for moving things like trottle levers, you might reach 4 Amps surges due to friction. Class A is still OK if you stay around those levels with some proper heatsinking and good control of motor torque. If you need more power (like my platform ~ 20A peaks) you need class D: PWM (Pulse Width Modulation motor control) and it needs to be fast >18kHz to make it work w/o the audible noise. After burning out numorous MOSFETs, I opted for half-bridge, driven by the IR2110 IC. Do a search and you'll find the data sheet. This works very well for the platform drive, but it needs +/- 12V 12Ah batteries for operation, and I haven't documented that circuit yet. The class A bridge for FF buffer circuit was posted in an earlier message. If you need me to post it again, let me know. (Extra note: I see now you are asking for ONLY motor polarity control. My above story assumed both speed and polarity control, which is necessary for motion servo control. Only polarity may be much easier, and could be done most easily with relays, as long as you keep the inductive spikes under control. however, I'm not sure you will be able to get realistic auto throttle with only on/off motor control. in most cases some position feedback is required, which brings you back to my original story)RgdsRoland

[Guest]

Hi Ronald, Yes, you are right-- I think buidling discrete H-bridge with transistor or such other components would be too compicated. However, I've done some research, e-mailing Ralph Robinson (EPIC CREATOR) regarding to Auto-Throttle. He recommend me to get H-Bridge IC which appears to be L298. And I thought it would be much easier to have it connected up along with Two 10 nF Capacitor, Two 10K Ohms Resistor, Four Diodes and Voltage regulator. Take a look at the attachment picture on diagram of circuit at below. To say this, this circuit must only allow up to 2 amps of current limit because I am going have it connected up to EPIC Output module. I know 2 amps would not give enough torque to move the throttle leveler, might as well only solution is to find motor that has more than 30 oz of torque, have the leveler weight much lighter than the expection, or adding gears train which will increase torque as far I know. About on and off (disengage or engage A/T) that is the issue I am concerned about. I am not famailar with servo motor but if the A/T is disengage and I manually move the leveler, I wonder would it just be a problem with motor since it's moving and if I get it engaged would it just get in proper position following by indicated airspeed from FS2002 program? Let me know more details.

[Guest]

Arthur,Let me to put my two cents here.What I am doing , related to your last paragraph , is using a RC servo and relays with FT 639 chip ( see www.ferrettronics.com )and a soft to drive the servo as per throtle position in FS2002.When I disengage the A/T , I remove the power for the servo, when I engage the A/T the servo is powered and it will go to the position of throtle extracted from the FS thru the soft, does not matter in what position is the lever after same have been used manually. The servo will switch the motor,thru the relays, the feedback will came from the servo's pot, and the lever will be positioned matching the lever in FS.Please note that I don't have EPIC.Regards.Alberto Kunzel

[Guest]

Alberto, Disregard to the question I asked earlier on other topic... You just have already answered my question. Okay now duly noted about how the servo work when the A/T is engaged or disengaged. Yes even if you don't get to use EPIC it still will work same with EPIC.