Thread

1. phugoid · 1789567102 · focus · HN ↗

   This really made my day! I was a flight simulator engineer for 20 years and it brings back fond memories of a project I worked on.

   Simulating the passenger cabin is important for crew evacuation trainers. Those are large, lifelike fuselage sections that you put on a hydraulic motion platform and run flight/crash/evac training scenarios.

   To get a realistic out-the-window view, the trainers I worked on had a PC monitor behind each window opening. We used FlightGear in a master-slave setup: the master node simulates physics and feeds accelerations to the hydraulic platform, and the slave nodes generate out-the-window visuals for each window.

   1. RobRivera · 1789569899 · focus · HN ↗

      [Desire to know more intensifies]

      So if I wanted to create something that could reliably jostle and move in response to a master physics node, like a racetrack simulator, cabin simulator etc. What kind of distributed controller scheme we looking at? Master node with strong compute, hydraulics with microcontrollers type set up?

      1. phugoid · 1789572199 · focus · HN ↗

         Hardware-wise, the industry has moved from hydraulic to electric motion jacks. It's great if you can avoid pumping high pressure hydraulic fluid. You want to think about capacity to handle the mass you'll put on top. Also, number of degrees of freedom and dynamic response (can it give you twitchy movements, can it also give you large accelerations by massively tilting the platform).

         You have a layer that translates the desired accelerations from a physics model (say at 60 Hz) into filtered motion jack length commands (say 400 Hz or more). You don't need massive compute, just keep the latency down and ensure a steady stream of commands to the jacks.

         The experience you get from the simulator comes from multiple systems hitting your senses at the same time. You yank a joystick and expect to feel a motion cue and see something in the visual system. For flight sims used in pilot training, you need a response within 150 msec and you want the motion and visual to be in sync to avoid motion sickness.

         A car simulator would be a lot more twitchy than passenger aircraft, 150 msec may be too slow.

      2. DANmode · 1789602431 · focus · HN ↗

         <a href="https:&#x2F;&#x2F;dofreality.com" rel="nofollow">https:&#x2F;&#x2F;dofreality.com

         Not to keep you from making a DIY version, but

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