Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Foo Off-Topic chit chat with no general subject.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 11-17-09, 05:48 PM   #1
Bikernator
Below Par
Thread Starter
 
Bikernator's Avatar
 
Join Date: Jan 2009
Location: Tulsa, OK
Bikes: '13 Trek Stache 8; '08 Giant Rincon
Posts: 188
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Engineers/controls people...

I am doing a senior design project right now and I've hit a bit of a snag. I'm a mechanical engineering student who hasn't taken controls in a while and need some refreshing. I've tried professors in the electrical engineering department but they were not interested and people in industry aren't as willing to help as I was hoping. Any help for this is not cheating or banned, this website as well as contributing members will be cited and listed under the references in my final report.

Materials:
2 electric linear actuators with limit switches which just stop the rod at the determined distance (i dont believe its an actual feedback signal)
1 remote control and receiver
Means of processing signal from remote receiver and delivering it to actuators (PLC or series of relays, i would think)

What i need it to do is this:
Press button on remote (prefer remote with only one button, but will use one with 2 buttons if necessary), actuator 1 extends, then retracts. Press button again and actuator 2 extends and retracts, repeat. The actuator will have a stroke of just around 2 inches, with required force of less than one pound. It doesn't seem hard but I have minimal experience with PLCs and i just can't get everything straight with the relays. And I know pretty much nothing about remote controls.

Any help with this will appreciated. If you can refer me to particular products or part numbers I will be eternally grateful. Thanks again.

-Brett
Bikernator is offline   Reply With Quote
Old 11-17-09, 06:05 PM   #2
Tom Stormcrowe
Out fishing with Annie on his lap, a cigar in one hand and a ginger ale in the other, watching the sunset.
 
Tom Stormcrowe's Avatar
 
Join Date: Mar 2006
Location: South Florida
Bikes: Techna Wheelchair and a Sun EZ 3 Recumbent Trike
Posts: 16,118
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
You need to shoot Phantomcow2 a PM. Not kidding.....this sounds right up his alley.

Quote:
Originally Posted by Bikernator View Post
I am doing a senior design project right now and I've hit a bit of a snag. I'm a mechanical engineering student who hasn't taken controls in a while and need some refreshing. I've tried professors in the electrical engineering department but they were not interested and people in industry aren't as willing to help as I was hoping. Any help for this is not cheating or banned, this website as well as contributing members will be cited and listed under the references in my final report.

Materials:
2 electric linear actuators with limit switches which just stop the rod at the determined distance (i dont believe its an actual feedback signal)
1 remote control and receiver
Means of processing signal from remote receiver and delivering it to actuators (PLC or series of relays, i would think)

What i need it to do is this:
Press button on remote (prefer remote with only one button, but will use one with 2 buttons if necessary), actuator 1 extends, then retracts. Press button again and actuator 2 extends and retracts, repeat. The actuator will have a stroke of just around 2 inches, with required force of less than one pound. It doesn't seem hard but I have minimal experience with PLCs and i just can't get everything straight with the relays. And I know pretty much nothing about remote controls.

Any help with this will appreciated. If you can refer me to particular products or part numbers I will be eternally grateful. Thanks again.

-Brett
__________________
. “He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you.”- Fredrick Nietzsche

"We can judge the heart of a man by his treatment of animals." - Immanuel Kant
Tom Stormcrowe is offline   Reply With Quote
Old 11-17-09, 11:14 PM   #3
iamlucky13
Footballus vita est
 
iamlucky13's Avatar
 
Join Date: Jun 2002
Location: Portland, OR
Bikes: Trek 4500, Kona Dawg
Posts: 2,118
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
First of all, have you talked to your mechanical professors? I'd be very surprised if none of them knew enough about controls to point you in the right direction, and very disappointed in the school if you don't have a project advisor to give you a little more in depth help.

A PLC is the most versatile way to accomplish this, although it can be done with relays. I think a couple of the relays will need to be the latching type, unless I'm just not being clever enough in my head. The ladder logic for a PLC won't need to be very complex. A couple hours learning from a decent ladder logic introduction should cover enough material for your needs. In the spirit of this being a student project and because I'm lazy right now, I will let you figure out the logic.

Hobby stores are a great place to look for parts if your remote needs to be wireless. You just need a receiver that can either close contact to a PLC input directly, or be used to trigger an additional switch to close contact on the PLC input.

Relays are simple. They're a switch that requires power. As long as there is power to the relay coil, it will hold the switch open. If you go the relay route, you will probably also need a couple latching relays. These close the switch the first time you feed them power, hold the switch closed when power is taken away, then open it again the next time you feed them power. You just need to know which terminals are for the coil, and which one's lead to switch contacts.
__________________
"The internet is a place where absolutely nothing happens. You need to take advantage of that." ~ Strong Bad
iamlucky13 is offline   Reply With Quote
Old 11-17-09, 11:17 PM   #4
gitarzan
Lost Again
 
gitarzan's Avatar
 
Join Date: Jul 2009
Location: Columbus, Oh!
Bikes: Soma Saga, 1991 Sirrus, Specialized Secteur Elite, Miele Umbria Elite.
Posts: 1,041
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Bikernator View Post
What i need it to do is this:
Press button on remote (prefer remote with only one button, but will use one with 2 buttons if necessary), actuator 1 extends, then retracts. Press button again and actuator 2 extends and retracts, repeat. The actuator will have a stroke of just around 2 inches, with required force of less than one pound. It doesn't seem hard but I have minimal experience with PLCs and i just can't get everything straight with the relays..

sounds like a door bell to me...
gitarzan is offline   Reply With Quote
Old 11-18-09, 02:22 AM   #5
busted knuckles
Senior Member
 
Join Date: Dec 2007
Location: wa
Bikes:
Posts: 411
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
doorbells sound more like "ding dong"
busted knuckles is offline   Reply With Quote
Old 11-22-09, 05:06 PM   #6
phantomcow2
la vache fantôme
 
phantomcow2's Avatar
 
Join Date: Aug 2004
Location: NH
Bikes:
Posts: 6,266
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
What are you using to control the linear actuators? Step motors? AC motors? DC motors? Are they linear motors?

I made a very similar thing to what you're doing for a play my college produced using a VFD. See if your drive has some external control mechanism (a response to a switch). For example, the VFD I used for the college responded to an opening and closing of the continuity between two terminals; opening the connection reversed the motor; opening another connection made it run forward; having no connections open stopped all operation. The opening and closing could easily be accomplished by use of a wireless relay, which you can find schematics for online and solder yourself.
__________________
C://dos
C://dos.run
run.dos.run
phantomcow2 is offline   Reply With Quote
Old 11-22-09, 05:17 PM   #7
Engyo
getting bent
 
Engyo's Avatar
 
Join Date: Nov 2008
Location: Houston, TX
Bikes: 2008 Rans V3, 1984 Trek 620
Posts: 241
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
A PLC would be easier, just because you can reprogram much more quickly than rewiring relays. That said, you just need to set up some latching circuits. Latch in the first one on the first button push, or even on first rod retract, and don't clear it until the second rod has retracted. Use this one to lock out the first rod from moving once it has retracted. Use the same thing in reverse for the second rod. With a PLC you could also use a counter setup instead of latching circuits if you prefer.
Engyo is offline   Reply With Quote
Old 11-22-09, 05:19 PM   #8
phantomcow2
la vache fantôme
 
phantomcow2's Avatar
 
Join Date: Aug 2004
Location: NH
Bikes:
Posts: 6,266
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Yea, PLC is out of my area of expertise. I can see why people would say it's easier, but depending on what his control mechanism is, a discrete component setup is pretty darn simple. Wire the limit switches in series with the terminals of the controller (if applicable).

What is your budget?
__________________
C://dos
C://dos.run
run.dos.run

Last edited by phantomcow2; 11-22-09 at 05:29 PM.
phantomcow2 is offline   Reply With Quote
Old 11-23-09, 02:38 PM   #9
Bikernator
Below Par
Thread Starter
 
Bikernator's Avatar
 
Join Date: Jan 2009
Location: Tulsa, OK
Bikes: '13 Trek Stache 8; '08 Giant Rincon
Posts: 188
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Quote:
Originally Posted by phantomcow2 View Post
Yea, PLC is out of my area of expertise. I can see why people would say it's easier, but depending on what his control mechanism is, a discrete component setup is pretty darn simple. Wire the limit switches in series with the terminals of the controller (if applicable).

What is your budget?
As it turns out, by simplifying the circuit to where one actuator extends while the other one retracts, it can be done simply using a relay. More simply, I found a transmitter that can operate two one-channel receivers with built in relays at the same time, by just staggering the receivers I get exactly what I want.... for $41

Thanks for the offered advice, everyone..
Bikernator is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 07:09 AM.