Planning a 2DOF Joyrider rig, need some help

Hello Everyone!

I've been putting time into planning a 2DOF rig, and came up with some questions. First an overview:

Rig will be used for flight/space sims, some racing as well
Total budget of about $800-$1000 USD (current estimate is $726)
Rig will follow joyrider design, and probably Tronic's additions
Rig won't be built for awhile, eventually used with Oculus Rift (or Vive) assuming offset issues get solved.
As a poor American college student, cost is a leading consideration for this build.
Screenshots of 3D model are attached (rough work, probably not suitable to make measurements)
Spreadsheet of parts, costs, and sources of parts attached.


Build specs:
2DOF Joyrider design (18 degree pitch and 45 degree roll in each direction)
Oculus Rift or HTC vive for display
Server PSU's for motor power
Arduino + monster moto or JRKs for motor driver
Hall effect potentiometers for feedback
Emergency stop button

So now for some questions:

1. Should I use wiper motors or worm gear motors? I know worm gears are preferred here, but wiper motors are so much cheaper. Will I still get a decent experience with wiper motors? Will they last nearly as long?

1b. How do I choose good wiper motors? I can find a ton on ebay for under $35 each, but how do I know if they'll be good enough for my sim?

2. Should I drive the sim with a belt system as tronic did, or go with a DIY actuator, such as the BFF actuator? I'm leaning towards belt for ease of construction and cost.

2b. If I do go for the belt system, will 1/16th inch thick aluminum angle be strong enough for the belt and pulleys? I know tronic used pre slotted angle, but that stuff is expensive! I'm planning on using regular aluminum angle and cutting holes myself.

2c. Does anyone have an estimate on how much aluminum angle I should get? It's quite difficult to estimate based off of tronic's website.

3. My current plan is to use an arduino and a couple monster motos. Should I use JRK's instead? Again, I know a lot of people recommend JRKs for their ease of use, but I can get the arduino setup for a fraction of the price ($8 for arduino and $11 for each monster moto vs $100 for JRKs). I am comfortable with coding and arduinos in general, so that doesn't scare me too much. Basically, is the ease of use really worth the extra $70?

4. Can anyone recommend a good and large electronics enclosure? Ideally I'd like to mount the PSU's in there, as well as a power strip, usb hub, and the other electronics. PSU's could be moved though.

5. Is it better to position the hall effect sensors directly on the gimbal for the frame, or (if I use a belt system) should I mount it on a pulley so it has more travel?

6. For anyone familiar with the joyrider design, I noticed something strange. The original design has a joystick built in which tronic then removes. That's fine, but he doesn't lengthen the base tubes to accommodate for the space that would have been taken up by the extra Tee connector. Doesn't this mean that his base should be about 5 inches too short for his gimbal? See attached image for details.

7. Finally, is there any easy way to add a button to the sim that makes it go to a predetermined angle? The goal would be to press a button on the dash and the sim would go all the way to one side and all the way back in order to accommodate shorter riders trying to get in. I'm guessing I could add this to the arduino code, but is there an easier way?


If you can answer any of these, or just want to comment on my project in general, that would be very welcome! Obviously I'm still in early planning stages, so anything can change. If you think something would work better, let me know!

And a final thanks to everyone on this forum! There is so much information here, and so many helpful people. It's great to have a place like this to come to for answers and shared knowledge.

Hi @YoruMusha and welcome
There's maybe some inspiration here from my project:
http://www.xsimulator.net/community/threads/my-joyrider-project-comes-to-a-life.3513/

Thanks for the replies!

I think I'm going to go with wiper motors and the arduino/Monster Moto for their cost. I can always upgrade the motors in a year or two if they wear out or if I want something more powerful. Building the electronics enclosure out of wood or MDF also sounds like a decent cheap option.

value1: I have gone through your thread before. That's a nice sim you have there! I especially like the idea of using a lever system to drive each axis. Would that still work for wiper motors though? I don't think they have nearly the torque of the winch motors you are using.

I also plan to build a joyrider but for the moment the project is on hold, I have to fix my house first. So I will follow your build with great attention.

Unfortunately petrus, it's gonna be awhile for me as well. I'm waiting for the Oculus rift or Vive to flesh out. Who knows though, maybe one of these days I'll get impatient and just go out and start building.

Thanks for the links noorbeast. The question I have now is, how much torque is needed to achieve desirable results on the sim?

I went through the calculations using rough numbers (exact figures are hard to find for wiper motors.) Using a wiper motor with 13.5 nm of torque at 70 RPM and a 4 inch (101 mm) lever, I calculated a force of 130 N could be applied at a speed of 0.372 m/s. Using my max pitch and roll angles, I figured out that the lever could be placed 12.94 inches (32.86 cm) from the pitch axis and 10.45 inches (26.54 cm) from the roll axis of the sim. At those angles, the torque produced would be about 40nm at 72 degrees and 43nm at 90 degrees on the pitch axis and 24nm at 45 degrees and 34 nm at 90 degrees on the roll axis. Is this enough torque to move a well balanced sim?

I'm a little confused here. The CTC is in millimeters, correct? So a 101mm would be .101 m CTC, not 1.01 as you have. That would give newtons of 133.7, linear velocity .74 m/s as you have. Then the rest is as you have it, with the exception of the new force of 133.7 N instead of 13.37 N, giving a final torque of 43.93 Nm, not 4.393 Nm.

I have the same problem when I run the numbers in the post you originally had linked. For a 40mm CTC at 180 rpm the force would be 500 newtons, correct? Because T=20 Nm /CTC=.04 m for a force of 500 Newtons. In the original post you had 50 Newtons.

Just to confirm, the CTC distance is the distance from the center of the motor to the end of the first lever, correct? As shown in the illustration attached, it would be the center of the motor to the end of lever 1. Or am I misunderstanding the CTC?

Your best bet is to find out the stall current of the motor and what what weight actually stalls the motor whilst using your desired leaver length. From this you will be able to determine what effective weight the motor can handle at a sufficient speed. One simple method would be to tie a rope the the end of the lever and on the other end put a measured weight.

Thanks for the help everyone.

It sounds like this is something that I'm just going to have to build and find out. Hopefully the lever idea works, as it would save me quite a bit in material costs.

Thanks again for the help!