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Author Topic: advice needed for linear actuator control  (Read 2654 times)
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hi

i am currently researching a few different options for a project i am working on, which invloves controlling 12 linear actuators using an arduino Mega, I have a load of these half h-bridge drivers :

http://uk.farnell.com/jsp/search/productdetail.jsp?sku=9592997

and I am hoping to use them to control the following 12v linear actuators:

http://www.ebay.co.uk/itm/12-volt-linear-actuator-with-electromechanical-clutch-/280986828141?

is this possible or should i be looking at some different h-bridge motor drivers?

i am hoping to be able to control the electromagnetic clutch on these actuators and was wondering if there was a way to do that with the EN pins on the above mentioned h-bridge driver..

any help would be greatly appreciated

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You don't need an H-Bridge to drive this unit.
If you read the specs that the seller gives it will answer most of your questions -

Electrical - six wires exit the unit through the rubber grommet and have the following functions:-

Yellow  - drives motor to pull shaft in (with 12 volts on Yellow and earth on Orange)
use a transistor or MOSFET controlled by 1 Arduino output to retract the shaft

Orange - drives motor to push shaft out (with 12 volts on Orange and earth on Yellow)
use a transistor or MOSFET controlled by 1 Arduino output to extend the shaft

Blue      - activates electromechanical clutch
use a transistor or MOSFET controlled by 1 Arduino output to activate the clutch

Green   - earth- or ground

Red) -Probably one end of the position feadback pot Try +5 V here

White)   - either end of resistance wiper circuit - probably the wiper of the feedback pot. To an Arduino Analog Input.

NOW - if you were to replace the internal circuitry with an H-Bridge you would still need the transistor or MOSFET to control the clutch. It would be much simpler to use a couple transistors/MOSFETS to control it than investing in an H-Bridge.
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You don't need an H-Bridge to drive this unit.
If you read the specs that the seller gives it will answer most of your questions -

Electrical - six wires exit the unit through the rubber grommet and have the following functions:-

Yellow  - drives motor to pull shaft in (with 12 volts on Yellow and earth on Orange)
use a transistor or MOSFET controlled by 1 Arduino output to retract the shaft

Orange - drives motor to push shaft out (with 12 volts on Orange and earth on Yellow)
use a transistor or MOSFET controlled by 1 Arduino output to extend the shaft

Blue      - activates electromechanical clutch
use a transistor or MOSFET controlled by 1 Arduino output to activate the clutch

Green   - earth- or ground

Red) -Probably one end of the position feadback pot Try +5 V here

White)   - either end of resistance wiper circuit - probably the wiper of the feedback pot. To an Arduino Analog Input.

NOW - if you were to replace the internal circuitry with an H-Bridge you would still need the transistor or MOSFET to control the clutch. It would be much simpler to use a couple transistors/MOSFETS to control it than investing in an H-Bridge.

I guess you and I just read those specs differently:  smiley-wink

Quote
Yellow  - drives motor to pull shaft in (with 12 volts on Yellow and earth on Orange)
Orange - drives motor to push shaft out (with 12 volts on Orange and earth on Yellow)

I read that as the polarity of the applied voltage on the yellow and orange wires determines the direction the motor will move/turn. So that means you can't have a permanent ground wired to either the yellow or orange wires, so that spells H-drive required where I hang out.

Lefty
« Last Edit: October 19, 2012, 12:00:30 pm by retrolefty » Logged

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A tle5206 might could be used for the h-bridge.

http://www.ebay.com/sch/i.html?_trksid=p5197.m570.l1313&_nkw=tle5206&_sacat=0&_from=R40
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Consider the daffodil. And while you're doing that, I'll be over here, looking through your stuff.   smiley-cool

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apologies for late reply, was away for the weekend.

zoomkat: with the suggested h-bridge (TLE5206) I am not sure how I would be able to activate the electromagnetic clutch.. other than that it seems a well priced H-bridge and more than capable of driving the actuator in question.

retrolefty: I was also confused by the description regarding the polarity of the yellow / orange and is why I thought an H-bridge was required, having used them in the past to reverse the direction of simple little DC motors it seemed like the solution. However, what confused me was the electromagnetic clutch and how to activave it through the h bridge, reading your comments and also kf2qd it seems that using a separate arduino output to activate the clutch (via a MOSFET) would achieve the desired effect.

the actuator should be here tomorrow, so will try out the different suggestions and see what works, getting a potentiometer working as per kf2qd's instructions would be great..

thanks again
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linear actuator arrived today, and seems to work great with the h-bridge setup, as retrolefty pointed out the direction of the actuator is controlled via the flip in polarity, with the clutch needing a separate 12v (via mosfet) control cable running from the arduino. I also needed to connect the earth from the actuator to the gnd coming out of the mosfet..
overall seems to work well, next step is to get the whole thing working over OSC..

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Manchester (England England)
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Can you say how noisy they are when they operate and what sort of speed they go at please.
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noisier than I planned for but as they are being used in a capacity where there is a lot of other sound design I don't think it will pose an issue, their main attraction for me was the price and the electromechanical clutch, which works really well. As for speed, it takes about 1.2 seconds to fully extend..
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Thanks, I am looking for something for the next 10 strings of my harp so it look like that will not do.
Cheers
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re: mike, glad i could be of help.

just had another quick question regarding this thread, hoping someone might be able to shed some light.
After getting the linear actuator working with the H-bridge driver SN754410 I had lying around (http://uk.farnell.com/jsp/search/productdetail.jsp?sku=9592997), I wanted to find a more suitable driver that could produce the 2A required for the linear actuator in question (the one i had tested with could only output 1.2A.. and I want to be able to get the maximum out of these motors).

I ordered the following component : http://uk.farnell.com/jsp/search/productdetail.jsp?SKU=403295 - which appears to be able to output 2A (per channel), however I cannot seem to get it to work, should it behave the same way as the other h bridge adapter?
I have wired it up as follows:

output 1 & 2 => motor pins
supply voltage => 12v external supply
input 1 & 2 => arduino pins 2, 3
enable a => arduino
gnd => gnd
logic supply voltage => arduino + 5v

the code i have (same as the one tested succesfully on the SN754410) is real simple :

Code:
  const int motor1Pin = 2;    // H-bridge leg 1 (pin 2, 1A)
  const int motor2Pin = 3;    // H-bridge leg 2 (pin 7, 2A)
  const int enablePin = 4;    // H-bridge enable pin
  const int clutchPin = 8;

void setup() {


    // set all the other pins you're using as outputs:
    pinMode(motor1Pin, OUTPUT);
    pinMode(motor2Pin, OUTPUT);
    pinMode(enablePin, OUTPUT);
    pinMode(clutchPin, OUTPUT);


    // set enablePin high so that motor can turn on:
   
    digitalWrite(clutchPin, HIGH);
   
    Serial.begin(9600); 
  }
 
 
  void loop() {
    // if the switch is high, motor will turn on one direction:
       if (Serial.available()) {

    char ser = Serial.read();

     if(ser == 'a'){
      digitalWrite(enablePin, HIGH);
      digitalWrite(motor1Pin, LOW);   // set leg 1 of the H-bridge low
      digitalWrite(motor2Pin, HIGH);  // set leg 2 of the H-bridge high
      delay(1200);
      digitalWrite(enablePin, LOW);
     }
     if(ser == 'b'){
       digitalWrite(enablePin, HIGH);
      digitalWrite(motor1Pin, HIGH);  // set leg 1 of the H-bridge high
      digitalWrite(motor2Pin, LOW);   // set leg 2 of the H-bridge low
      delay(1200);
      digitalWrite(enablePin, LOW);
     }
     if (ser == 'c'){
       digitalWrite(clutchPin, LOW);
       delay(100);
       digitalWrite(clutchPin, HIGH);
     }
     if (ser == 'd'){
       digitalWrite(clutchPin, LOW);
     }
  }
  }

but i cannot get any response out of the motor, is there a difference in the two h-bridge adapters that i have missed? should i wire this up differently?

any help would be greatly appreciated

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Have you paralleled up the signals on both bridges. That is enable to pin 6 & 11, In1 are pins 5 & 12 and In2 are pins7 & 10?
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just tried it.. no response as yet.. looking online it seems that the setup requires some more components than i had not anticipated, a number of capacitors etc. I have ordered a simple motor shield from ebay that uses the same L298 driver, so will see how i get on with that..
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