PT-Actuators 3DOF system?

Hi, the IGBT part is this big white part with the many through hole pins:







As you can see on the board I also had to replace some high voltage capacitors ( red part) and add a few pieces red wire to replace the burried traces that were burned out as well...

Like I said, it's not simple repair unless you are electronics engineer. You need to trace surrounding parts to make sure the IGBT failure didn't bring them down as well.

Thanks
Thanos

Thanks for your help Thanos. How's the noise level on the PT actuators?

Noise level? If you mean the 10khz noise that was annoying for some in the past, its not present in the new AASD-15A Plus drives. They have new IGBT with 16khz switching now, that is not audible.

http://www.pt-actuator.com/products/p5/58.html

Thanks Thanos

I've always found the 'squeal' from the controllers to be quite annoying, to the point I keep meaning to make a little sound reducing enclosure. Having recently had my ears tested, I can hear above 16KHz. Do you know if there are any dB levels of the new and old AASD-15's available?

I don't have any of the new PLUS drivers to check DB levels, but here is a screenshot of measuring the 10khz from the old drivers:

Try this audio test to find out above which frequency your ears cut off:




I couldn't hear anything at above 15Khz....

Thanks Thanos,

Well, Im not a dog, but I can hear to about 16-17KHz on that vid using headphones. There are a lot of harmonics in that tone probably down to Youtube compression artefacts on the audio. If you have a decent tone generator you don't get any of that. Saying that I still don't hear my wife most of the time she is telling me something important

From your picture above thats a big old 10KHz spike but also stuff above! It sounds like the new drives would be a big improvement on the noise front as our ears are less sensitive up there. The older drives are not terrible though neither are they silent.

Sorry for the necro/revive on this thread, but this question seems to fit here the best: Would the PT Scorpion Ultimate actuators in 300mm length be safe/effective for a 3DOF setup? I haven't seen many 3DOF setups with actuator travel longer than 150mm, and I find 100mm actuators to be great for heave, but lacking in roll/pitch. For driving sims, there are a lot of tracks with pretty aggressive grades whether it be hills or banks.

Ha, no worries - I think most of us are happy for an excuse to discuss this stuff!

I think there is good reason why you don't see long travel actuators on motion systems, and its not just down to cost. I personally hardly use any of the travel of my 100mm PT's. Mine are usually set between 30-50% of max. IMO, in 3DOF with driving SIM's, its all about the heave. I think main issue is latency - actuators simply cant react fast enough to give fully convincing pitch under breaking. Pretty sure this shortfall would be accentuated with longer travel. Its the quality, not quantity of the movement and why the horrendously expensive D-box systems are so revered with their seemingly pathetic travel. Tbh, I would halve the travel of my 100mm units if it meant they were twice as fast. That in theory would be possible with reduced gearing from the same motors. In fact I think I'm going to send an email to Shao now

From what I can tell, you would be far better investing in a seatbelt tensioner to complement a 100mm actuator system to enhance immersion. That's what I would have done had my seat been compatible with one.

Thanks for the response. When it comes to pitch/roll, I am actually just trying to recreate the position of the car due to track gradient changes, so not trying to emphasize pitch due to acceleration or deceleration, nor emphasize roll due to cornering/lateral g-forces. For example: Eau Rouge is approximately 18 degrees uphill at its steepest part, so in my ideal world, I would pitch back 18 degrees. I realize that in real life, due to g-forces, it doesn't seem exactly feel like 18 degrees static pitch since the body is pressed aggressively towards the bottom of the seat, and not just into the seat back, but I guess having a rig that could better approximate track gradient changes is my goal. In VR, I find this to be very immersive, especially since the actuators can typically keep up with this sort of change. I would be interested to hear if you manage to reduce the gearing though!

Fair enough. I use SRS so AFAIK when you increase pitch for say gradient, you will also be increasing it when you have a crash - so i've tended to err on the side of caution to avoid the inveitable 'bucking bronco' scenario. You can have accel+decel effects independently set from the maximum pitch, but its the former aspect that stops me from using the full travel. Not sure if there is a way of controlling this other than the spike filter?

Big travel totally makes sense in a flying sim where your not going to have frequent crashing events. Maybe I just need to drive better



Regarding the actuator 'speed up' I had a look at this old video from Barry, and remembered there is no gearbox in these actuators - so the only way would be to either change the lead on the actuator ballscrew and nut (1605 to 1610?) or get a motor with a faster nominal RPM. I assume doubling the lead would halve the weight capacity rating, while increasing the RPM while retaining the same torque would require more power - so a more powerful motor and driver combo would be needed?

I've emailed PT - so I'll see what they think and let you know the outcome. Probably a non-starter for a commercial actuator, but it did get me thinking someone on the SFX-100 forum must have investigated this as an option?

I and many others moved from a 5mm to 10mm ball screw pitch and it is really worth the effort. I run 1.8KW servos so plenty of torque, although others with 750W servos seemed to also work well. Since moving to big triple screens I am not moving my sim as much as I use to in heave and also keep any surge and sway movement to the bare minimum for gear changes etc. Did have big heave setup in DCS with VR and motion cancellation and it is very convincing (800mm screws). Note sim has changed greatly since that video.

but unfortunately for some unknown reason most other sims do not really support big heave movements very well - even had a chat with the SRS developer about it.
It can also move fast if it needs to note reset after crash at 0.58 in video below. I do use a spike filter to stop it hurting my neck/spine.

Wow, 800mm ballscrews! Thats mega. If it threw you out that could really do some damage!

Can you please elaborate on what the difference was like before and after when you changed from the 5 to 10mm versions?

With a 5mm pitch it would often max out speed wise during a large motion change causing tracking issues. The 10mm screws tracked way better and is also now used in most 6 DOF Stewart platform Setups on this site for the same reason.

For anyone finding this thread in October 2024. Sim dash Motion dot com has the (4) Actuator PT Champion GT for 3299 w/ free CONUS shipping. Limited time. (regularly 3999USD)

Great deal for someone in the US who's looking to go full motion 3DOF for the holidays !

Pff.. why anyone would trust PT after what Shoe pulled?

I'd suggest instead for another vendor that uses official Thanos parts and offers great quality and support... and $300 less after shipping...

Apologies if I stirred the pot.

I wasn’t aware of any issues and don’t have the context.

I am not a big fan of someone stealing another’s work and profiting from it, so I absolutely appreciate your reply.

I had already decided on the 3dof RS Mega myself, before posting the above. Mainly because the actuators are more consistent with off the shelf parts (for future repair or enhancement) .

It helps that they’re using legitimate Thanos controllers which is a no brainer for all the aforementioned reasons.