progress of a cheap diy 6dof moving platform for a soaring flightsim

[douwe]

Hi,
Reporting some progres on the HI6SIM as shown at the FSWEEKEND
Updated mij site with some pictures, sw and a video.
And how to use a mini rolcentimeter to report the length of the platform legs.

[wannabeaflyer]

Hi Just to say great work you have done and like the design you have used for your actuator .. have to say like most wannabe Simulator pilots making a cost effective actuator for the home DIY user is always a problem but have to say that your concept looks like something that can be done within the cost parameter so good for you guys do you have any specs regarding the Load carrying Capacity for each of your actuators ... I have built a 2 DOF platform but would ideally like to go initially for 3 DOF as i said great work and Nice Project you have just gained another very interested in you concept regular site visitor Cheers..

[fweinrebe]

Nice work there on the HI6SIM.

I was wondering, are there any good resources/websites that explains the difference between the DOF platforms?

[Roland]

Having build both 2doF and 3doF here are some of my findings:

2doF normally concern pitch and roll. The platform normally pivots on a centerpost, that takes all the platform weight, hence it can take bigger , heavier constructions.

The pitch cue is a great help in making convincing acceleration/decelleration experience. It is really realistic feeling the aircraft accelerate during take-off, or decellerate in the air when extending flaps.

Roll is great when mimicking the lateral acceleration during turns on the taxiway or runway. I also find it feels natural to add a little platform roll during slow banking in the air.
BTW, when the pilot sits high wrt the pivot point, fast lateral turbulence can also achieve believable lateral motion when the platform is quickly exited with short roll pulses.
One fun item : when doing engine start at small single prop GA like cessna: I added some decaying sinewaves to the platform roll based on low engine rpm; This mimicks the prop and engine start-up / shutdown back-lash. I got good comments about this effect from people during the Fsweekend demo.

So 2doF already can add a lot to the sim experience, and it’s relatively easy to build and drive.

Adding the third DoF is normally heave. (vertical movement).
This is mechanically more challenging, as you need some sort of balancing system to take the platform weight off the servo motors. Some use springs, or air-pressure chamber, I used bungee cords.
Heave is a very dynamic motion. Additional cues include runway wheel bumps, positive / negative G-feeling when pitching up / down. What I like best are the short bursts of vertical turbulence during flight and the touchdown bumps.

Jim has added a 4th DoF, yaw. (rotation around vertical axis) I can’t comment on that, as I did not add this. Jim was very positive about this addition.

More DoF normally means a hexapod system like Douwe has build.
This system is both hardware wise and software wise quite a challenge, but is has been done hardware wise by Douwe, and Nicola has shown that it is possible to build the hardware and software in DIY fashion. Though I have to admit Nicola’s software skills are way above average.
6DoF solves a lot of the compromises that lesser DoF have. The fact that you can mix the various motions (surge with pitch / sway with roll, ect) means that you can accurately simulate the onset of a certain acceleration (surge) and make it fluently into a sustained acceleration (pitch). Also the fact that you can make pure lateral movements and mix them with yaw, makes it perfect for simulation uncoordinated flight. Lateral motion is what felt really great when I took a ride in a commercial airline simulator.

Hope this helps.

[douwe]

The maximum weight should be about 150 Kg with air pressure balancing installed by means of 3 bicycle pumps with a expansion bottle at the 3 corners of the platform.
See the following picture when testing by pushing on a scales:
http://www.mijnalbum.nl/GroteFoto-TAROFKGG.jpg

[douwe]

Weight compensation bij means of bicycle pumps installed.
Ideas about MK IV.
And other updates, todo list., see website.
Hoop to have something working again before the FSweekend.
See some of you there.
Douwe

[meo_udon]

Look great. How many watts of motor?

[Goldmember]

Great explanation. What you and Douwe are doing is great work. Speaking about software, I think this is the most challenging part for most builders. My feeling is that most people who can do construction work can build a platform for well under the huge prices of commercial motion platforms. On your site I read you use this software. Is it capable of doing 6dof? Or would you know if anybody has 6dof motion drivers that they want to share?

[Goldmember]

Great work. We met a few times at FSWEEKEND and it's nice to see the proceedings. I wondered, have you ever considered this concept:



True, the servo motors are more expensive than your vacuum cleaner motors but would you recommend it to somebody with a slightly higher budget?

[douwe]

Look great. How many watts of motor?

In this setup the power spend on 1 motor maximum to about 200 W.