2DOF wiper motor sim, continuing.

Hi there all!
Firstly, thanks to DERIY for his sim setup. I will be using some of his design setup.
I will be modifying my current sim as per my avatar pic.

I have two wiper motors $30 bought second hand, 5 old stock tie rod ends and two big arse ball joints bought for $30 from my brother's auto parts shop.
My plan is to use a plastic chair seat to begin ( for weight reasons ), cut and modify the base of the current sim, build a motion base for it to balance on with one of the ball joints. I have a large piece of 30mm thick board which I will use as a base to figure out the pivot/balance point for the seat-wheel-pedals frame and motor placement. I will build a steel frame base later (looks better, I think). From this I plan to get the balance point, then run the motors with on/off switches to get an idea as to how much weight they can swing. I would like to setup the surround sound speakers , ( the sub will sit on the floor ) and 24 LCD monitor. I would like to build a DERIY seat with speakers attached at the head rest and the front speakers on a aluminium frame at the front for the monitor to sit on.
Electronics side will have to wait till late April, as I have rego on a car soon. Unless I can scrounge a spare $200 from somewhere. I am still evaluating and with the assistance of eaorobbie in Australia, the best board control option. I know the famous pololu 12v12 works, however, I am interesting in the K8055 - relay setup as well. The K8055 is a cheaper option, but it may be more headache to setup.
The current PC should handle gaming and sim control. It runs an AMD 965 quad core 3.4 gig, 880 chipset motherboard, 4 gig 1600mhz ram, gigabyte GTX 460 1 gig OC VGA, 600 watt power supply, Antec 902 case.
So it begins! I will work on the base modification and motor setup this and next week. The wife and kids are sick, so they are keeping me busy. I will post new photos of progress each week.
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Re: 2DOF wiper motor sim, the beginning.

I'll pretty much be building the samething as you... Waiting for the Polu to come instock.

Re: 2DOF wiper motor sim, the beginning.

Next step, today I cut a board at 1200mm x 700mm and put 3 castor wheels on the bottom (couldn't find the 4th ;P ) that I had in the garage cupboard. I had some aluminium round brackets that I drilled out more and bolted the ball joints to. One ball joint I mounted on a piece of wood as the pivot point. It wasn't till I cleaned up that I realised that I had it 50mm off centre. Fetim! I will re-drill and mount it tomorrow. The screws holding the wood down have a breaking strain of 100kg per screw, so they should hold. I may bolt it in place later. This is the development board.Also in the photos are the tie rod ends and wiper motors. The tie rod ends just need threaded rod to connect them. The motors will be mounted on brackets bought from the local hardware store.

All done in 30 mins, including looking for the stuff!

Re: 2DOF wiper motor sim, the beginning.

OK, I had some time today so I stripped the current sim frame bare, fitted a plastic seat off a school chair (for weight savings,as the original car seat may be too heavy), fitted a cross brace underneath at about the cemtre point of weight distribution. Oh, and I moved the ball joint to centre as it was 50mm off. I sat on it and it withstands my weight with ease and swings around well - so far. Although I am only 80kg.

I now need to find some threaded rod to connect the tie rod ends. I bought some L brackets today for the motor and frame pivot mounts.
My plan is to setup the surround sound speakers and monitor on the frame. I was thinking of hanging some springs via brackets off the front to allow some weight support without affecting the motion of the wiper motors. This will take a few spring tests.

Re: 2DOF wiper motor sim, the beginning.

You guys work so fast
Have to decided pololu 12v12 or K805 ??

Re: 2DOF wiper motor sim, the beginning.

I have landed a week off work, and had time yesterday, but will have no time the rest of the week. Other stuff to deal with. I have not yet decided as to Pololu JRK 12v12 or K8055. The pololu looks easier to set up, however the K8055 may be up to $100 cheaper, but require more work. The electronics will have to wait till late April regardless of stock or not. I have a car to register first. All other fiddly bits I can squeeze though.
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Re: 2DOF wiper motor sim, the beginning.

Damn camera is not working! :freu: Hopefully I can get pics tomorrow .Today I mounted the motors on L brackets and had the tie rods ends welded together at opposite ends to each other. I quickly fitted brackets under the frame, applied power......Damn! The frame hits the motors stopping the motion! This also fried an old power supply I had as it overloaded . Rats! Time to use the car battery for test I think. : So, tomorrow I will mount the motors out of the way, raise the frame a bit, put on some longer brackets for the tie rods ends to attach, and give it a spin. I am a bit lost with fulcrum points, but I think I may have it right. As the motors will not be doing 360 deg motion, as long as I can get a smoothish movement for up and down, I should be right.

Re: 2DOF wiper motor sim, the beginning.

Today, I raised the frame another 50mm with two more blocks of timber, fitted a timber under the steering mount and mounted the motors in , I hope, a good position and attached them with brackets to the frame. The tie rod ends I welded together.


The frame will need a pivot pint at the front to stop movement around , like the DERIY setup.
I gave the motors a quick spin with a small 12v source. They moved, be it a bit slow. But it works! So far so good.

Re: 2DOF wiper motor sim, the beginning.

look great.

Re: 2DOF wiper motor sim, the beginning.

Getting there.....

Re: 2DOF wiper motor sim, change of plan

I am re-designing the set up to something like a joyrider, but the frame made of steel box 20 and 25mm . This will allow me to put on the screen and speakers and not worry about the wiper motors struggling to shift them as the weight will be on pivot points. Hoping to weld up something this weekend and during the week. Stay tuned :hi:

Re: 2DOF wiper motor sim, change of plan.



Ok, the new plan is to build a joyrider style frame with two pivot points. The steel used for the outside frame (roll) is 2 x 20mm box welded together on top of each other to support the weight (yes I know I need practise welding ;P )
. The existing aluminium frame will be the inside pitch frame. I cut another piece of board 750mm x 1700mm with the castor wheels underneath. This still needs to get in the front door of my house. The outside is 1600mm x 600mm , the inside is 1150mm x 480mm. I will set up height and pivot points later this week. I have some big castor wheels to use. I am looking at about 300mm height of the board to give room for electronics, motors, swing of inside frame. I am also still planning to put the speakers, a better seat, and 24 monitor on , as well as the current driving force gt wheel and pedals.
I may build a frex design later if I have enough leftover steel. I got an old truck load gate for nothing! It gave me a quantity of 20mm and 25mm box mild steel.
Thanks.

Today, I set up the frame to get an idea of height. I will need to cut it down to 250mm to 300mm overall height from the base. Currently at 500mm high at the base. I found some great bearing and housings that will hold the weight no problems.They cost me $30 each x 4. A bit costly but well worth it. I still need to work out a correct pivot point for the seat as I am placing a screen and speakers on it, that and the seat is on rails for smaller individuals to adjust and use (7 year old son). It sits well so far. The frame should swing 100mm up or down at the ends from motor mount. Not enough to toss me out, but enough to create some motion. The motors on their brackets and the tie rod ends have a total height of 260mm. I may put some blocks of wood under the frame as well to create a bump stop. Its going well so far. I should have the frame all set up by end of next week. Then to save some cash for electronics. I would like to get pololu's if money allows. I am about to spend $750 + on registration for a car due middle of April.

;D

Finally got the motors in place and tested them, all is good, but a bit sluggish under my weight. That would be due to testing with a car battery. A proper power supply will be built-bought in time. At this stage, I am leaving a reasonable amount of clearance under the frame to house the sub for the speakers, power supply and anything else that may need to go under. After that I may cut it down height wise.
I have yet to fit the speakers and screen mount. Will do that at a later date.


Please ignore the bad welding. I am going to re-weld later.
And videos of motion

http://www.youtube.com/watch?v=kvoth1mzuPQ

http://www.youtube.com/watch?v=Eyt1NGzyo4M

Any comments, thoughts or advice would be greatly appreciated. :happy:

Looking good :thbup:

One thing I would like to add,
I'm afraid that the construction is a little bit too high.
When you add the monitor, and your weight to it, left-right movement could flip the whole thing.
Maybe you could lower it or make the bottom wider or the tripods (front and back) more robust or wider at the base.

ok looks like ya got the concept.
Except the centre of your body weight should be no higher that the centre of the outside gimbal, with the joyrider design fully weighted sim with you in it should find its centre balance point at rest, therefore less power is needed to roll or tip the gimbals off their balance points, thus taking away alot of load(amps needed) to drive the sim to its extreme points. Quickens the reaction time aswell.
So i recommend spending some time to find the right point as it will help later once setting the electrics up,

A little off subject, still sims, pricing components for tronics amc and h bridge here in Australia, pcb is easy to etch but sourcing components is a little tricky here in Westrern Australia. Plus have another company pricing 240v gearhead motors and varible speed drives that will hookup to the k8055 expect pricing in 2 days (just gunna keep the price away from the wife already in trouble for the money I've spent developing the 12v sim) It works why keep stuffing with?? she asks, But its fun.
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Thanks for the tips. I can make the seat frame sit lower. Just a matter of welding up some side frames to drop the centre of gravity. I can lower it but not much unless I raise the frame. Some more playing around I think! I will drop the middle by 200mm and see how that goes. Purely for reference, the current setup is quite stable as I have swung myself on it with no tipping over movement. Still, time to drop it. By the way, judging from the pictures, should i move the pivot point bearing? With me on the frame , it seems to be right. Any thoughts?
Thanks again for all the advice.

If batteries don't get you moving, no power supply will.

I agree, you have to move the pivot points to the center of gravity, otherwise the wipers are going struggle and you will only have slow movements.

With such a frame I would also avoid pushrods, and go with a chain/belt drive system like in many other joyride designs.

Thanks for the advice Frakk. I suppose I could use bicycle chains and gears. Would they be strong enough though.

However, purely for reference, heres what I did today.


I lowered the middle frame by 260mm, and hey presto, a lot easier to swing with me in it, at least twice as good! And the balance is a lot better.I know lower would be better, however, I am trying to avoid buying materials (cheap bastard I am!). It would mean raising the outside and constructing a new side bracket for the inside. Do you have any further thoughts on this? All help is greatly appreciated!
Cheers, David.
Also , I forgot to mention, when I tested the wiper motors, I used light duty speaker wire, so this would have reduced the power flow. I will give it another go with fatter wire before looking to the bike shop!

By the way, could you please advise on centre of gravity, would it mean the motors on the outside edge away from the centre bearings? Or closer to the centre bearings? I find it easier to swing from the furthest edge possible from the bearing centres.
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