Wish to find out more on how 2 dof 15V Dc motors work

[boons4]

Hi Guys,
I am lucky to have my first 2DOF DIY motion rig custom built by MotionDave here. Had been enjoying the rig to the fullest for past three weeks! so much so that all my other hobbies shelve...Now i finally have time to seat down and reflect on how actually this 2 dof works.. Love to ask questions here so that other folks may benefit as well when they read the words of the builders and experts here. Pardon for my ignorence question as I am not mechanical or electrical trained. All along i race alone so i can't see the motors in action as well. Until now i still wondering how come two small black motors can lift up 90kg of weight with such speed and force!.....??????

Q - Is 15V dc golf cart motors considered as same mechanism as wiper motors which many bros used here? Where are better? I really love the earlier one as of *

Q - Is it true that the 2dof motors only needs to do the below action to have realistic car racing motion?
- left motors push up the rod and right motors pull down so then we have lateral seat movement to tilt right? same goes the other way for left tilt.
- both rear L n R motors push up or pull down so we have the longitudinal or pitch force motion for forward and backward movement?
So with the above, how can we get the vertical up and down movement of road feels? Is it not possible? But Yet i felt the road un and down feel perfectly... This is where puzzle me how 2dof can do it?

Q - So what is a 3rd dof for? For what movement?

Thanks.

[motiondave]

Do I have to answer everything?...........

The motors are a worm gear like a car wiper but much stronger inside. They are very strong and even surprised the supplier as to how strong they are.
Car wipers run at about 6nm torque, yours run at 20nm torque. Thats rated, not stall. Sim motors are always under stall torque which is higher. That and a good balance point helps to support the weight of the driver. Get the balance good, and even a hamster on a wheel will move you.

Motors going left or right is based on frame design and nothing more. My motors go opposite to yours with the same effect.

A 2DOF (2 degrees of freedom) is a basic sim design. Even though it only goes back and forth and side to side, it tricks you brains otherwise. Sure you lean forward under brakes, but your mind thinks your body is being forced forward , opposite applied to acceleration. Same thing with side to side, it tricks your brain into thinking you have body roll of a car. Even playing dirt and drifting around a long corner, you will find your self leaning in the seat to counteract the drift motion, even though your frame does not have a drift. All a mind trick.
If you wanted actual heave in a frame, you would need a complete redesign and a winch motor underneath to create lift. However, a good vertical motion profile tricks the brain into thinking the sim is lifting.
3DOF is usually heave or lift, you would feel the bumps by it pushing you up and down under you. a 3rd DOF could be a "yaw" or drift frame where the frame swings at the rear creating drift. Once again, a redesign of frame.
Hopefully that helps.
Cheers, David.