My project : Zero-gravity, 4dof

very good job

Hi stowaway,

I usually do not take notes in my programs because I do not have to share the code. I will look where information is needed and post the motor class and a sample application.

Hi,

Yes I did but without satisfaction. With a new profile the start was good but after a lap motion was less and no motion at all after 3-4 laps.
What happened is that the maximum was increasing constantly and became useless.

Now I set a fixed maximum and adjust the intensity until I am satisfied. It is very easy to change it from 25 to 28 if it is too subtle, or from 40 to 35 if too harsh.
As for minimum it is always 0 since I want to feel everything that happens.

The sun gets in the room from the window in front of the simulator making it difficult to have good lighting. I will have to do it in the morning.

The movements are Roll, Heave, Pitch and Sway. Yaw has it's center but sway does not. My simulator has a pivot 1 foot in front of my feet. Rear motors are connected at about 50° to the rear of the seat and lateral g make them move the seat to the right or left.
You may consider it as a 3DOF with extra, it is up to you.
I do not think Surge is significant in a race simulator (it is just my opinion).

This is a very complex project and I do not recommend anyone doing it exactly like I did.

This is a concept simulator, just like some concept cars are not designed for mass production or marketing but are lab.

As for drawings, I can not draw since I do not have to use it my business. Yes I have a CAD but each time I want to use it (about once a year) I do not remember how it works.
I use http://www.emachineshop.com/ free software because it is very simple to use but only for 1 part.

However I am already planning the next generation that would reproduce the same movements but with a simpler system.

Hi,

4 actuators (wiper motors in a prior life) are used : 2 in front (one on each side of the seat) and 2 in rear connected in the middle at an angle that provide the sway movement

Thanks

Great looking sim, and good ideas.

I'm using a pneumatic cylinder with an expansion tank in my sim to unload the pitch axis. I'm going to install the cylinder in the next few days.

Just a suggestion if you do look for bigger motors for the sim at a later date, you can try these http://www.motiondynamics.com.au/worm-d ... orque.html
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Hi bsft

These motors are powerfull indeed but in my opinion MUCH TOO FAST. Do you realize that at 60 rpm you will switch from full right to full left in half a second ? What would it be at 180 rpm ?
I know people that built Cobras with 800hp engine and they do not use it, why ? NO DRIVEABILITY.
I want to race on my sim at will, not only 3 minutes.
The weight of the frame seat and myself is 270lbs and it is ALL supported by the air cylinder @ 86 PSI. All the motors have to do is move us and fight inertia and I think they do it pretty well. They are adequate.

Nothing above is personnal but a lot of would be X-simmers are stopped because they think they cannot find powerfull motors. All is needed is a well designed sim.

Consider that a Lotus Exige has a very small engine compared to a Dodge Viper. Would you bet on the Dodge ?

By the way the current draw at 16 amps is out of consideration, that would be like 20L/100Km

Ok, point taken, just a suggestion, thats all.

It is what I did and I am delighted with the result. My expansion tanks are heavy and a heavy base makes a stable sim. Their volume is 50X the 50mm cylinder which has a stroke of 125mm (limited to 95mm which is the stroke of the motors). Make sure you have a 12mm hose between your cylinder and tank to reduce restriction as much as possible. If you can mount the cylinder on some kind of trolley, on rollers do it so you have sway movement too not just up/down.
If you are using a microcontroller you program, have it monitor the air pressure on every loop and open/close a solenoid valve as needed to maintain the pressure even when you race.

About the castor wheels I use polyurethane because they are silent and my wife can watch TV on the next room without my door closed when I race and wear my headphone, she is not bothered by noise.

I use 25amp winches to great effect road bumps feel like road bump, teeth rattling plus jumping causes ya to nearly loss ya stomick that floating feeling then thump as the car botoms out.
By the way ya results are nice and flowing a flight sim would run very nicely on it. I used wiper for about 12months then the plastic worm gearing eventually gave out on it, balance is not an issue one a 80kg person is seated only 5kg of force is needed to push it to the extremes and back. Really just using the power of the winches to throw the sim hard and fast when needed.
The main thing i think most of the new ardunio guys would like to see is ya code mate, but understand if ya want to keep this under wraps for now.

Here it is

this is the class for motors
motor.h
motor.cpp

this file has to be renamed MotorDemo.ino since ino extension is not allowed to upload
The demo will allow you to try it with a pot as controller
MotorDemo.cpp

I will also make a demo to use with the test plugin

These xls/ods files will help you visualize the result AFTER you have read 8232
NoPID.xls
NoPID.ods

About a flight sim, I did not show it but I have already a handle bar and pedals rack with my Logitech G940. It is a matter of 2 minutes to change it. I do not fly because I find there is not enough action (read adrenalin) and it is too complicated.

And you are right the plastic gear is the Achilles heel of my simulator.

My motors have plastic gears, but I'd say they are of good quality. No problems here.

Hi bsft,

Thanks for sharing this. It is good to read that.

How long have you been racing with those (in hours) ? Where do they come from ? I read you like your sim to give you a ride like a roller coaster and that 30 minutes will give you a sore back and you feel they will last, right ? I do not know how eaorobbie uses his and why they lasted only 1 year.

I like my ride to be smooth and what counts to me is having the feeling of the handling and that includes the track surface condition.

My motors come from '03 GMC trucks and when I tested them by bolting them to a bracket held in a vise, I was happy to compare what I saw with the specs of SCN5. I used a pail with 25lbs of material in it and it would raise it without problems just a bit slower than with 15lbs. I could not test with more weight because I would have to make a sturdier bracket. I was satisfied enough with the result.

By the way I use them on the slow speed for 2 reasons : they are the same speed cw/ccw to 1rpm close and more torque than high speed. I think I made a pretty good choice but I also think their weakest point is the plastic gear even by protecting them with damper bushings.

Hello, FernVeilleux, my motors are apparently 12 volt golf buggy motors. They may be rated at on 20nm, but by golly they have some kick! Granted they are 180w though.
The plastic internals are very strong, even with smashing direction changes like I do. I even surprised the supplier of these motors with the abuse I am giving them and that they have lasted no problems. I used to have wiper motors and I only chopped out 2 , mainly on the side of my old joyrider frame.

I solved it with a extension spring on one side to create a constant load against the motor, just enough to put a bit of a load so the gears were more constantly meshed together,despite direction change. This stopped worm gear destruction for me. After the springs were fitted on, I had no more problems with chopping out wiper motors.
As for my back being sore after 30 mins, let me define that, I get off my simulator and I can feel the tension in my back from the shaking I have been getting during gameplay. It is not cannot walksore, but tender and I do feel it later. I am probably getting old . :rofl:
I can game happily for as long as I can, but lucky to be up to 2 hrs once a week.
As for your ride, please do not get me wrong, it looks great the way it moves, and you have said you like a certain style of motion for your sim, not so many bumps. You have developed a real nice motion there. :thbup: You have taken the load off your motors via the airbag spring. This would stop wiper destruction.
Everyone has had success and failures with wipers. All part of design and testing. I like wipers, they are cheap and survived me. I went to bigger motors for durability and boot.
Finally, yes my motors are 180rpm unloaded, and probably 100rpm loaded, havent checked. However, I can slow down that further with the PID settings.
Cheers and go hard. :

Hi bsft,

Nice on your part to share your experience and views.
It was a clever to use the spring like you do. Yes I think those motors are designed mainly for golf cart which are heavier and faster than wheelchair ones. IMHO 60rpm/8NM is about the kind of motors that are suited for the kind of sims we have. It does not hurt to have faster and more powerfull ones as long as you are not trying to push them to the limits... Our limits are much lower I think.

Finally I do not think racing your sim will make you older but keep you young longer. Maybe you should see your doctor about your back ;D

Thanks for the advice about seeing a doctor, my main concern is that if I turn up at work with a stiff back, I have to be cautious about telling them how I got it! :rofl:

Thats looking awesome! That side to side movement is what i thinking in my little head but i newer could think that the air is the answer. Good to know that someone thinking same way :clap: