Relationship between end of crank arm & mounting point on platform

Hello,

does the mounting point on the platform always have to be a certain distance accross from the end of the motor shaft?



Is it that the motor shaft is directly below the platform mounting point when the platform is level? Or does it not matter?

I hope you understand the question lol??

90 degrees is in reference to the two arms. This means that there is equal travel in either direction. The two arms should be at right angles to one another.

Great thanks, can you see the new picture I have uploaded above? I mean the actual rod that connects the motor to the platform, does the top mounting point always have to be at a certain point compared to the motor shaft?

When the platform is level the actuator arm should be halfway through its arc of travel.

Exactly what I needed, thanks! So the position of the vertical rod is not really relevant as long as it can move all the way along its arc of travel?

thanks

Another note as you will see in picture it is not recommended to have the connecting rod at 90 deg when motor arm and platform is level, try to avoid this as when it goes to 90 deg ,the connecting rod can tip past 90 deg , plus the angle actual helps to lessen the force on a motor, basic physics of levers.

with a picture!


Nice work, mitchellmoxo!

I would disagree with that, not good a method you are losing a lot of motion range by doing that.
Sorry.

eaorobbie,
I have started my framework for a platform, ac unit like in the first pic...IF I understand you correctly, with the crankarms , either at top / or / bottom of stroke - 180 or VERTICAL, then the
rods connecting at frame should be somewhat offset - not vertical with crank? Hope this makes sense.
Thanks,
cthiggin

Tell me more as I don't understand

here is my tought

yours

Simple physics of leverage at 90 deg you are supporting 100% of the weight on the lever. at 45deg you are only have 50% of the weight leaning on the motor arm. This allowing for better speeds as the motors have to work less, a bonus on any sim. Plus at 90 deg like the picture above you are inviting radial movements as the lever will not stay dead vertical, it will always try to fall over which in turn will stress the pivot point. I completed 3 years of a Mechanical Engineering degree but left it in the final year to support a growing family plus I really do enjoy building things then dealing with the politics of an office.

Back to the question. Yes please aviod the arm being vertical at rest and max movements even layed over at 80deg will be fine, the frame above is a copy of the CKAS unit which they fail badly at the motors are way too slow to be used in a race scene as they advertise. Their software doesn't help either. 26rpm way to slow for motion cues always lagging behind missing a lot of the feeling.

How about having motors/actuators further towards the edge of the frame. And away from the pivot. Granted you may not get the giant angle , but actual leverage would help to lessen the strain on motors.
And yes , having to use really powerful motors to overcome bad design is a CKAS idea.

bsft,
That's what I had planned to do - motors /cranks / arms at the edges of frame, middle left/right for roll, one at middle rear on edge for pitch, all three for heave. I have and will be using 1 hp motors with
a ratio of 30 rpm gearheads (which are high torque) AT 60 hz. If I need more speed, I can increase the hz up to 100....I have several videos that I have saved from other ac setups and they are quick -
much quicker than the CKAS. At least this is what I have in my mind to do.
Love this particular thread.
Have a blessed one folks

For good racing motion cues a min of about 60rpm is needed to get the best feeling for road vibrations etc, Some vfd's allow up to 400Hz which then brings the motion cues close to a dc motor speeds, as in we use 150-180 rpm motors on our rigs but nowhere near the torque of a AC motor, please be careful with 240/110v systems, I would advise the involvement of a qualified electrician in that part of the build, hate to see you get fried or burn out electrics in your house mate.

@eaorobbie : Hello!
I wish I could see a sketch about angles! as I don't see what you mean

Have you actually measured 150 rpm under load? or it's the datasheet specification?

obviously a 150prm motor is going to be faster than a 60 rpm wiper motor. Duh!

Yes the motors are rated at 180rpm under 100kg load they slow to 150rpm tested with a meter, I dont stuff around when I quote stuff mate, all tested and proved. Built 9 units with my technique and never had a complaint even modded peoples sims from wipers and scn5 to big worm gear units plus removed amcs and ards to people surprise the little jrk kicks arse with the right motor on it.
A sketch sorry not my post and I think i clearly explained myself.
I appoligize to mitchellmoxo if you require more information mate happy to give.

Thanks,
150 rpm under load, it's really great! what was the lever length? as load matters in N.m (torque=force x distance)

it's a pity for the sketch... sorry to bother you if I'm the last one who hasn't understood

Its all about balance of weight not lever length.
Well Winches I ran 180mm centres and big worm on a seat mover is only 45 mm as any longer still work just fine but results in way too much motion for a seat mover, ie 10 deg is ample or you end up being pulled away from the wheel and pedals. This is the basics of sim build shame you dont even understand the basics -Mat.

eaorobbie,
Thanks for the info on ac/ and speeds....absolutely will have involvement on wiring the 230V circuit.
Have a blessed one.