Showroom **RIP** - 6DOF project using 12v DC Motors, Sabertooth 2x60's (was MM's) and Arduinos + OSW

Well the rig is in bits again lol

I'm increasing the angle of the actuators and I think it will help just by feeling the weight of the load with 1 actuator disconnected from the rig I can tell that it feels lighter which deffo should help my cause. I have also drilled holes in the motors to let some air in because they are totally sealed there is no chance of any air to get in and circulate. Also taken the opportunity to make some proper base plates to weld the UV joints to on the bottom of the actuators with 4mm sheet steel this also gives me an extra 35mm to play with whilst raising the angle. I reused my old brackets and bolted them to the top of the platform which gives me an extra 120mm so with the greater angle the platform is actually at the same height

Pictures to follow

Well the rig is back together new angles and holes in motors




Excuse the welding never had to weld in a circle before

Just need to get cleaned up and get testing ............... again

Why are you making your motors fight the weight of you and your seat when you can add vertical support with little to no hit in performance? Gas springs are a great start. I believe they should not be left out.
I have been thinking about a design that uses constant force springs. Should be very little drag and a nice constant force that takes gravity out of the motors work load.

Also I would think you would want to keep the bigger actuator angle. It seems your most prominent motions are sway, surge, and heave. The motions from sway and surge dont utilize all 6 motors fully. So I would think those motions would need the most mechanical advantage(bigger angle from verticle). Heave uses all 6 motors nearly equally so it can stand to loose some mechanical advantage to sway and surge. Of course as mentioned above gravity really needs to be removed from the work load so you can just worry about inertia.

Here is a video you all have probably seen. Even though it uses crank arms the utilization of each motor will be very similar. Check out what moves on sway, surge, and heave.








Loving the progress so far. Keep it up!

I know all about gas springs/struts I had them on mine. The way this is designed it shouldn't really need any springs. Its looking good at the moment. The way actuators work, so I have found out, is completely different to crank arms the angles of them and everything perform in totally different ways.

I'm afraid you are wrong about Surge it uses the same amount of axis on all 6 actuators, where did you get that misinformation ? Sway use 4 axis the same and a little of the other 2

Edit: I may be completely wrong with Surge if your using proper 6DOF math but the way I have to do it I use all 6 axis

Sorry for the confusion. I did not mean that all 6 motors are not working. Just that there are some motors working harder than others(moving faster and farther). Therefore not all the energy to move the system comes from all 6 motors equally, as it does in heave. The video above really does a good job of showing this. Look how far the cranks move on each motor during the different motions.

Unfortunately in reality Springs/Gas dampeners are not the panacea that you may think, just like in a car they can introduce unwanted oscillations (springs) or under/over dampening (Gas dampeners) of the rig all which can effect the movement of the rig. Ideally you would use none. My rig will operate without them, but I have connected just 3 x 10Kg (100n) Gas dampeners to reduce the load a small bit and hopefully increase the life of the motors etc without over-dampening the movement of the actuators.

That's interesting that you would say ideally you would use none. Do you have any further reading on that idea? I would like to learn more.

When your been around long enough, just basic engineering common sense - but to ease your mind, just Google 'Car spring oscillation' - which will show how a spring will oscillate and why we used matched dampeners to reduce this - a car is no different to a simulator rig if you support it with springs and dampeners, although in our case we actually do not want to dampen the movement, as the sim may have difficulty tracking what is being sent from the simulation software. Free world, you can take my advice or ignore it - no need for the passive aggressive statement.

Can you feel the difference in the motion with 100N gas struts or without?

I can only say from my old design that they did make you lose the tiny movements, with the rig the way I have it now I can feel everything im sure with 100n you wouldnt lose so much as the actuators work very different to the wormgear motors. The feeling is how can I put it, is just different, in a better way.

Yes, but it is only very slight with 100n struts and I'm happy to live with it, as the rig is still very reactive with none of the settings on maximum - as it becomes just too stupid rough for me (maybe not @SilentChill ).

Thanks for the answers @SeatTime @SilentChill. i should go for strong motors right from the beginning

Could you test your rig already @SilentChill ? How hot do the motors become with the holes and the different arrangement?

Its definitely better with the increased angles and holes in the motors. Testing going really well and I am getting more and more happy with it, I just need to tweak all the tuning centre settings now I have the PID somewhere near where I want it to be.

Little video of NoLimits2 wind is working great although you can't tell from the video



More DirtRally soon as that will break it or make it

@SeatTime me bothering you again Could you have a look at these Axis settings do you have something similar or am I way out lol

Think I've got the rotation in the right spot and it feels pretty good. Yaw is actually traction loss just easier to test it using Yaw

EDIT: Axis % is purely for testing I don't use that amount in games

Depends how you have your actuators numbered/placed in relation to the outputs in simtools, Might be telling you to such eggs, but just do one DOF at a time and it should be obvious if something needs adjusting. Your been down this road before just linear actuators this time.

Yeah I did setup one at a time took me ages as usual, i did have a few totally wrong. just wondered if you had similar values. I think and I feel like it's nearly spot on

Party time at my house and the rig has had 4 hours straight is in one piece. One guy snapped off my handbrake so had to screw that back down and then someone else snapped both brackets off the G27 lol Had to use cable ties for a quick fix got it through the night.

All in all no nausea from anyone which is good and most were pretty pissed

Quite a few heavier people than myself on it so happy days

That's always a tough test. Also lost my G27 brackets long ago to someone who panicked when they ran into a wall. Bolted it into the frame with the available screw holes under the G27 and it has not been an issue since. Did the same with the shifter.

good idea