RiftFlyers G-Seat

[spyderwash]

I had no problems of jitter and I have not changed the pid perhaps also depends on the components used maybe smaller engines the mine.
however my project to a halt for lack of time now I have to build a base to put the seat 6DOF

[BrassEm]

I have pure proportional control now (as seen in the last video) and hope it can work ok. I was unable to remove the hunting when using integral and derivative values in the PID.

What value of P do you have?

End to end travel of 90° is around 0.9 seconds. Maybe too slow a response??

At 3906hz and a PWM power offset of 0. A PID of 1.0,0,0 would give me no overshoot as seen with an oscilloscope. Any higher and I got overshoot. As per the XPID setup instruction upping the P till it breaks into oscillation - I went up to max P and it did not oscillate? So I could not up the Derivative to critically damp out that oscillation. I've only ever got the integral up to 0.4 before it breaks into a slow half second oscillation.

[RiftFlyer]

I got a chance to return to this project. I have progressed a little bit and now have the mechanical arrangement of the rear seat flaps and tensioners finalized.

I need to secure the pots and the brackets on the rear of the flaps.

[RacingMat]

Excellent news!!

[RiftFlyer]

I have moved out of the garage and back to the PC to start on the electronics wiring. I really need to find time to visit the local car breaker and source two more motors for the seat base!

I'm now planning my wiring for the two HP power supplies. They can be connected in parallel but I am debating keeping a separate circuit for the seat back and base.

I'm not 100% happy with the toothed belts and pulleys to the pots. Even when tensioned as best as I could there seems to be the chance of the belt skipping. I may have to add an idler pulley to maintain tension.

[RiftFlyer]

Edit: question removed. Issue resolved.

[RiftFlyer]

I have finalized the power system for the actuators. I am using separate 12volt supplies for the base and back of the chair. Power is being provided by the trusty HP DPS600pb server power supplies. Each is rated for 47amps.

I made up a switch box to keep the wiring tidy. Each supply has its own switch. Power is passed through a fuse to a relay to the motor monster shields. The relays are connected to a kill switch which is mounted within easy reach

Internals of the power box



Power supply switches



Here you see the proposed mounting location.

[LukeV]

Looking great mate! I am about to build one also.

Has anybody considered hinging the front of the seat (seating area only), and adding 2 linear actuators to the back part (pivoting from the front) so that the seat can sink during g maneuvers? I mean in addition to the force applying flaps..

I've pulled 5g in real life flying, and in addition to feeling the weight something else very noticeable is the fact that you sink in your seat. It would only need to sink 40-50mm at most right beneath your back side. I've seen fairly cheap 12V 900N linear actuators from China that would easily handle the task I would imagine.

Couldn't pressure plus sink work for a even more realistic g feeling?

[RiftFlyer]

I've considered a few different ideas. The effect you describe should work with the traditional flap setup. If positioned correctly as the flaps raise you feel pressure at the sides and also sink on the inbound section of the flap. Positioning is crucial.

Another guy I know is considering making the seat base out of canvas to achieve the effect you're looking for. Consider a folding camping chair. As the outsides rotate the centre of the canvas sinks.

[LukeV]

I hadn't thought too in depth about the positioning of the flaps to also create sink. Sounds as though that method could work.

The canvas base also sounds like a great concept to imitate g-force sink, but seems it would lack the weight force sensation beneath the thighs and buttocks. It also lacks lateral force simulation - which how much of that is felt in a fighter anyhow? Most would be felt in the back wouldn't it? Like during a snappy roll maybe..