2DOF Joyrider Flight/Race Sim Build

As always @noorbeast that is extremely helpful! I'll need to go back and read the FAQ's to see what else I missed the first time

Here is my old "simulator" which had to be disassembled to make room for the new one. Less a simulator than a static playhouse themed like a spaceship. Working knobs, buttons, lights, sounds, night vision camera, etc. But the kids outgrew it and it didn't move, so time to upgrade!

Made just a little bit of progress. Welded up the lower half of the inside frame, and got a few of the other parts on order.

Received two hall effect potentiometers today. $15 USD each plus shipping from DigiKey. That is really expensive for a pot, but not if they work better and avoid problems down the road. They are 180 degree sensing, but allow for 360 degree movement with no end stops. That is nice so I won't break anything in case my motors run away. Really smooth movement compared to a normal pot.

The first odd thing is there is no zero mark. And then there is the question of what happens after it reaches 180 degrees? Does it just peg at 0 or 5V for the other 180? The only thing I can do is hook them up and run a few tests to see how this thing works. The datasheet provides no help at all.

The question for the group is where do I mount these on a Joyrider? I can put them at the pivot points on the frame, which should provide the most accurate positioning for the rider. But if there is a lot of slop (backlash) in my drive levers, that could cause the motors to oscillate trying to hit or hold a position. Placing them right at the motor shaft probably means more consistent control of the motors, but lack of accuracy for the rider. Pots at the motor means my lever assembly needs to work symmetrically, especially on the roll axis to make sure it rolls the same amount left and right.

My motors have a tiny pilot hole (maybe 3mm) which a could use. My other option I'm considering is connecting to the ridged coupling instead of the shaft itself with some kind of flexible connection to the pot. It sounds like reading directly at the motor is better than downstream, which now has me second guessing whether the pitch motor should move with the roll axis instead of being stationary on the ground. If the motor rolls, that means I'll get an accurate pitch regardless of bank angle. It also means I won't need to use ball joints. The downside is adding maybe 10kg to the weight that has to be moved, plus a much longer wire run.

I ran some tests on the hall effect potentiometers, and got those sorted out.

Pot: TT Electronics 6127V1A180L.5FS - http://www.digikey.com/product-search/en?keywords=987-1392-ND

What I'm calling the 0 degree position is the flat on the shaft facing directly opposite the anti-rotation pin and Vout pin. I'm working with a clockwise rotation.

0-90 degrees = Constant low voltage 0.21 V
90-270 degrees = Voltage increases with clockwise rotation to 4.88 V
270-360 degrees = Constant high voltage of 4.88 V
Once the pot hits the 360/0 degree mark, it makes a sudden drop from 4.88 to 0.21 V

This is a nice setup, since it means if you overrun your 180 degree range of motion, you have an extra 90 degrees before something ugly happens.

My second hall effect pot was just a tiny bit different, with a 0.21 to 4.84 V range.

Just received my G27! I need to resist the temptation to play with it instead of working on the sim . I'm surprised by the weight (18 pounds / 8 kg). I'm getting more and more concerned my sim is going to weigh too much to move! My motors only have 26 ft-lbs or 35 Nm of torque.

This may become obvious once I start using the G27, but why do most sim's tilt the pedals forward so far? The G27 already have what looks like a reasonable angle on the pedals, but maybe the pedals are setup with the assumption you are using a desk chair? In my sim, my seat mounting is only 1" above the bottom floor - just like my Mini Cooper.

Not much of an update today. Just 3D printed some guides so the sliding cover for my enclosed cockpit will stay centered. These are small - about 1/2" square. I could have made these by hand, but a nice excuse to use the 3D printer for something useful.

I had to play with the G27. My first FFB wheel and it is amazing how much that adds to the experience by itself.

The problem is those plastic mounting clamps on the bottom of the wheel! My knees hit them even with the wheel mounted higher than I would like. I had assumed they just pop off, but apparently it is a significant warranty voiding process to get rid of them. I'm not quite ready to do that to my brand new, $250 wheel. I'll have to mess with my cockpit geometry to see what I can do without a major rebuild.

Maybe your pedals are too close?

Very slow progress recently, but I'm finally getting back to it. Got my new gaming PC, got JRK's on order, and purchased enough steel to finish the middle and outer frames over the next few weeks. I've sorted out the positions of the seat, monitor, and various controls. The balance point is pretty far back, but that shouldn't be an issue. Not sure where it balances vertically yet, but I'm planning on rigging up a test this weekend.

Finally got the time to weld up the middle and outer frames. Right now it balances out really well, and takes surprisingly little effort to move with a person in it. But a lot of the components aren't mounted on it yet. Just sitting in it and having it roll and pitch with slight body movements is already a lot of fun! There are nothing that limits the range of motion yet, so I've been lucky not to flip it upside down and smash my head on the ground yet - something that would be really easy to do.

Now I'm working on the motor mounts. That is a big step, since once those are done I'll finally be able to tell if motors can actually move this thing.

I decided not to wait to see if my 1/2" acrylic motor lever was strong enough. Once I got the frames assembled are realizing how much weight has to get thrown around, my gut was telling me that even a thick piece of acrylic was likely to crack right away.

Following a tip from @noorbeast I got a ridged coupling, cut it in half, and welded those to some 1" x 1/8" steel. No question these will be strong enough. I'll be cutting at least 1" off one of these for the roll axis so both motors can make a complete rotation and not hit each other.

I had been thinking I was overbuilding my rig and making it too heavy. I was also concerned my 42 RPM motors would be too slow. But I got my pitch motor hooked up and ran it with no driver to see what would happen. Without a person in the rig (and some of heavy stuff like the screen removed), the speed and range of movement is pretty ridiculous. It was violent enough that it almost immediately pulled apart my motor mount assembly and twisted the upper lever assembly mounting bracket. I'm going to have to reinforce some things, and start with the levers connected in the holes with the shortest CTC (center to center) distance for the least extreme movement and work my way up from there. I would be afraid of getting in this thing running full speed unless it slows down a lot with a person in it!

I wish I got a video, but it tore itself apart too quickly for that.

Here is a very short video of the pitch motor in action. Once I reinforced the motor mount and a couple other things, it seems to be holding together okay - at least with an empty sim where the moving mass is maybe only 20% of the final version. Once the JRK's and feedback pots are in place, the motor won't make a complete revolution like it does now. The motor is surprisingly loud, but hopefully I'll be able to get rid of the loud bang that happens as it reverses direction when hit reaches full-down pitch.

these are pretty strong motors. long sessions leave me sore.