Hello, I'm an HVAC guy with a ho 1

[ROCHESTER]

Hello,

I'm an HVAC guy with a hobby of flight simulators. I'm working on some projects for force cueing hardware.

I use pneumatic cylinders pressurized by an I/P to apply a proportional force. This works great, but others don't have the option of compressed air. And, there are the hazards of working with pneumatics.

Question: Is there a electric actuator that can be driven to provide a proportional force?

Thanks

 

[advidana]

I Think i saw flight simulators operated with electric actuators as part of a kit in a soft ware flight magazine. I keep my flight sim magazines at my office I will check went I go to work.

 

[ROCHESTER]

Is this the Co.?

http://www.q3000.com/

 

[jbartos]

Suggestion: Visit

http://www.thomasregister.com

and type Actuators: Electrical under Product or Service, which returns 171 companies to approach to.

It appears to be feasible: Visit

http://www.bray.com/docs/Brochures/cd-act-NR090.pdf

for a sample

 

[ROCHESTER]

Thanks for the links.

Sorry, I wasn't clear in my first post. I use a pneumatic actuator as a force transducer. Votage to Force. I use an E/P(electronic pressure regulator) to supply a proprtional air pressure to the pneumatic cylinder. I drive the E/P with 0-10VDC. The rig applies a constant force regardless of position(within cylinder stroke.

I use this to apply force feedback to things like rudder pedals and joystick. I'm looking to apply forces in the 200-300lb. ballpark.

Thanks,

Craig

 

[jraef]

That is quite a "hobby"!

The problem you are going to have in directly replacing a hydraulic or pneumatic cylinder is that for the time being, electric acuators convert rotary motion to linear for the purpose of movement. You are not really wanting a linear actuator as much as a force actuator. A linear motor would possibly do it, but I'm not sure if they are marketed yet for that purpose. Do a google search on that term and see what you find.

A different approach however would be to change from your cylinder method to a rotary motor type of system where your pedal connects to a rotaing shaft. Then you can use a servo motor to apply a precise force to the shaft and maintain it at whatever level you want.

Quando Omni Flunkus Moritati

 

[ROCHESTER]

Hi jraef,

Thanks for the feedback. I'll search "linear motor".

You wrote:

"A different approach however would be to change from your cylinder method to a rotary motor type of system where your pedal connects to a rotaing shaft."

I don't know what a "rotary motor" is. Can you drive this to a torque value???

 

[jraef]

Just happened across this when searching for something else, thought you would be interested.

http://www.manufacturing.net/ctl/article/CA194009

Quando Omni Flunkus Moritati

 

[jraef]

This is very similar to what I had in mind about doing it with a rotary motor (as opposed to linear).

thread237-76060



Quando Omni Flunkus Moritati

 

[ROCHESTER]

jraef,

Thanks a bunch. I've been very intrigued by the suggestion in you're first post. If I understand it correctly, you apply enough power to a motor to output a desired torque.

You can stall a motor like this continuously? If so, does it take a certain type(i.e. 3 ph, DC, etc.)

It'd be great if I could take a single phase motor and drive it w/ a VFD. Refresh my memory please, can you reverse a single phase motor?

Thanks,

 

[jraef]

Yes, you can do this with AC motors using vector control VFDs, and yes they can give you 100% torque at zero speed continuously. You will need to be concerned with keeping it cool using external methods since the motor fan will not be functional. It would not be practical to do this with a 1 phase motor, there are too many different types, most of which cannot be accurately controlled for your application.

True Vector AC drives capable of torque control as you need are for 3 phase motors. However, most VFDs will accept 1 phase input, some even 120V, and give you a 230V 3 phase output anyway. So if you do not already have the motors it should be a moot point. Assuming that you do not need much power, the trick will be to find a smallish VFD with vector control. Several are available that are "Open Loop" vector, meaning that they calulate the required output based on current feedback signals, but those are not accurate at zero speed. You will need Closed Loop, where you have an encoder on the rotor or load shaft feeding rotor position into the drive. If your load is small, it might actually be more cost effective to go with a servo drive and motor. The position fedback is built-in.

Quando Omni Flunkus Moritati

 

[jraef]

I just re-read your earlier post.

"I use this to apply force feedback to things like rudder pedals and joystick. I'm looking to apply forces in the 200-300lb. ballpark."

Did you mean inch-pounds or foot-pounds?

Quando Omni Flunkus Moritati

 

[ROCHESTER]

jraef,

Thanks so much for your time, really appreciate the help.

What do you think of this hair-brained idea?

http://mysite.verizon.net/vze323mw/sitebuildercontent/sitebuilderpictures/elec_force_acuat.jpg

Calc the force from the compression/extension of the spring and control the rod position with closed loop.

 

[jraef]

I suppose, although at first glance it looks like there a lot of places for error, i.e. spring tension, gear slap etc. etc.
I suppose I don't really grasp what you are trying to accomplish. Are you trying to simulate the force required to push a pedal against a control cable going to a rudder or flap in an aircraft?

Quando Omni Flunkus Moritati

 

[jbartos]

Comment on the previous link: It appears to be too mechanical concept. The electromagnetic principle would have the following advantages:
1. Less friction
2. Less lubrication
3. Could be magnetically levitated
4. Less wear
5. Higher accuracy
6. Etc.

 

[ROCHESTER]

Hi jraef,

Sorry not to get back sooner, been real busy.

I'll try to explain better the concept. I have several places in my simulator where I'll need these "force transducers". I need to apply a force over a range of motion. Here's a sketch of the pedals:

http://mysite.verizon.net/vze323mw/sitebuildercontent/sitebuilderpictures/pedal_actuator.jpg

This is my interpretation of your motor idea. The pedals need to rotate +/- 45 deg. The application of the force need to held constant while the pedals rotate.(NOT like pushing against a spring).

 

[ROCHESTER]

Hi jbartos,

I feel like you EE's are ganging up on my mech. design. :-D

One of my main design criteria is price. I'm looking to do this with cheap consumer products or components bought on eBay. I've been watching 1 phase to 3 phase speed controllers on eBay and it seems they can be had for a reasonable amount (~$100US).

I need to pull out my text books and size the motor for the torque I need. I'll post this for you to critique.

Thanks,

 

[ROCHESTER]

jraef,

I just noticed I didn't answer this:

"I use this to apply force feedback to things like rudder pedals and joystick. I'm looking to apply forces in the 200-300lb. ballpark."

Did you mean inch-pounds or foot-pounds?

Yes, 200 -300 lbs force. WWII fighter plane develope tremendous forces on the rudder pedals and stick. When I'm done I'll have a fun way to get some aerobic excersize.

 

[ROCHESTER]

Found this on the web:

http://www.wittenstein.aero/e/pdf/WITT-100_activerudder.pdf

The "force transducer" is called "control loading". Seems they also like the EE approach. :-D

 

[jbartos]

Comment on bricklayer (Mechanical) Feb 5, 2004 marked ///\\I feel like you EE's are ganging up on my mech. design.
///Not really, I just provided options, which is normal in this Forum.\\One of my main design criteria is price. I'm looking to do this with cheap consumer products or components bought on eBay. I've been watching 1 phase to 3 phase speed controllers on eBay and it seems they can be had for a reasonable amount (~$100US).
///The linear electromechanical actuators are probably less expensive and will have lower operational and maintenance cost than various gears, and special mechanical and structural constructions.\\I need to pull out my text books and size the motor for the torque I need. I'll post this for you to critique.
///This is just a matter of aligning couple of curves, motor Torque-speed and Load-torque speed. I noticed that even some secretary girls can do that.\\