3 dof inspired by h3

hi
i am starting a project inspired by "DOF Reality Motion Simulator H3"
i am waiting for the delivery of a wheelchair motor 24v 220w which i hope have couple.

for the electronic part i am thinking of starting with itb-2,Arduino Uno r3,smc3 and see if the project works and maybe deserves a sabertooh.

this simulator is delivered with optional steering dumpers
I do not quite understand the usefulness apart from adding a constraint, this type of shock absorber does not return to this position like a spring.

Thank you for your reply.

What do you find marginal in the specs?
Speed 50 cm/s (86 °/s)
Torque 25 n/m

On some diy simulators I regularly see springs to "help" the engine.

I don't quite understand how it works because it will be help to go up but will add additional force to go down?

The dampeners on the DOFReality H3 are to provide smoothing to mask the effects of backlash on the gears of the gearbox attached to the motor. The H3 uses a universal joint as a pivot point and there is a bit of freeplay when you move past the tipping point. Carefully balancing the weight on the rig apparently helps quite a bit to mitigate this. They have a new gearbox system now that uses a short ball screw moving the lever instead of the current arm on the gearbox design. It apparently works quite well and looks like a clever solution, though presumably you lose some fidelity compared to a more traditional linear actuator.

As a side note, the mentioned freeplay in the gearing can be a considerable problem. It's not such a big deal for racing sims using small, fast movements as you often won't notice a bit of a wobble, but with flight simulations using a larger and slower motion, it can be very obvious and immersion breaking if the rig doesn't move correctly and smoothly through the whole motion.

DOFReality also has a 6 DOF version that uses gas struts to provide smoothing and additional lift to help the motors push against gravity.

Springs are often used for the same purposes - i.e. providing a bit of preload or assisting an underpowered motor.

Thank you very much for all these explanations, I hope to succeed in having the minimum of Backlash in my assembly.

the springs seem to me a good solution remains to draw and test I have different springs in stock that can help (bad in calculation)

hello thank you all for your help.

currently i waiting for my engines (returned to sender for an unknown reason).
i continue to analyze the model and make diagrams, i have noticed that the distance between the gimbal and the connecting rod is greater in width than in length.
I imagine the torque will be greater to move from right to left compared to front to back? Does that seem logical to you compared to a square?

Insert image IS possible only by URL?

Thanks

ok i understand better thank you.
I will install simcalc as soon as possible and test the difference in torque between a rectangle and a square
(a photo would have helped to understand this sentence)

my question was more to understand if one movement needed more torque than the other

in the example (rectangle h3) the movement right left is wider so more torque (I suppose)
I will check this with the software.
I hope to be able to illustrate my remarks soon.

concerning the ibt-2 or sabertooh I have heard of the risk of overvoltage or intensité by Dynamo effect of the motor I have great difficulty imagining that even a sudden movement of 120 degrees can provide so much intensity or voltage it IS a guess or a real problem?

for sabertooh some are installing resistors and on ibt-2 diodes ... do you think it would be better to install diodes?

ok so the left right axis is wider in order to relieve the engines
it may seem logical that the constraint is greater on this axis compared to front rear the weight is perhaps better distributed

hello

I come back after having finished my first engine.
(If you have any questions about the modification ask.)
I tested it with a weight after one meter and an ampermeter.

Your predictions what is the torque of this engine? (24v 220w 150rpm)

hello,
I'll put an end to the suspense...
I was very shocked at the weight that this motor lifted and so easily.

I started the test at 12v, it lifted 5.5 kg at 75 rpm and 11 kg at 150 rpm at 24 v...
before buy second-hand motors I looked at the motors sold for simulator from 35nm to 65nm and a speed around 50 rpm. (24v)

Is it better to use it in 12v so that it is closer to the parameters of engines sold for simulator (75rpm 55nm) or the fact that it is very strong and fast is better?

Hi
I heard that the torque is never too much.
but that the speed (150rpm at 24v) can be a difficulty in setting (pid, setpoint overrun)

I am looking for information on this subject
I still have to learn the software part, I don't haven't started the chassis yet, I'm gathering the parts and preparing the future engines

I can confirm this.

I am using very similar wheel chair motors and definitely recommend using 24V.
Some time ago one of my two 12V power supplies stopped working, so that the motors were running with only 12V. The result was that they were much less responsive.

I don't see a speed of 150rpm as an issue. A high speed just means that the rig is responsive. If you encounter too hard movements, you can still apply smoothing filters.

hello,
thank you very much, that's reassuring.
have you shared your work here?
I started to make a model of the 2dof part (cooperative engine) based on existing diagrams.
The idea being to find the placement before welding the chassis.

the radius of the circle is 30 cm and the middle between the motor shaft and the crank (between 4.5 cm and 6 cm) is placed at 45 degrees.
the gimbal is at the center of the circle.

Yes, here is my build thread:
My 3 DOF motion-enhanced G-Seat