2DOF Compact Seat Mover Using Winch Motors and Steering Boxes

Yeah, the first time it is really like you have described. There's still a lot to be done, but there is a way to get them less noisy.

The MMs can handle the peaks without any issues. The PSU is too weak or has a protection short circuit built in IMO

That is great. Please keep in mind: better slower winches and longer levers than faster winches and shorter levers (noise reduction). I assume you have watched my videos, the winches are audible but not so loud that it would destroy any fun factor.

PS: I advise you NEVER stick a winch on a wooden plate or on something which has a resonance. The better the winch is isolated the quieter it is. The best results I got on a heavy stone plate, the screws must not touch the winch, nothing should touch the winch directly at least (all has to be isolated). You will sort it out, I am sure

Yes, as you can see in the video I placed a noise reduction mat below it and then placed an insulated box (which I used for external harddisks some years ago) above it and it was already a lot better.
Still not nice but better. But putting the motor in a box can cause heat problems... leaving a whole for a fan will lead the noise to the outside again. Some rubber washers will help for mounting.

@xytras with the way my winch testing has been going so far, I don't think power will be an issue anyways.

The noise was an issue for me as well on the winch motors. It's the biggest reason that I ditched the entire gear train that comes with the winch and instead used the steering boxes for gear reduction.

What kind of power supply are you using for your testing? I haven't really looked into how I'm going to power my simulator yet; I've just been testing off a car battery.

A superb idea, would you kindly share which steering boxes you have used?

@Pit the steering boxes I picked up are from late '80s Chevrolet S10 pickup trucks. I think most of the 2WD trucks with 4 cylinder engines came with manual steering boxes that were a lower ratio than the power steering boxes.

It looks like it should be fairly easy to splice them onto the motor shaft. The motor output is a 6 spline shaft, so I'm figuring a pipe with three set screws drilled and tapped into the pipe 120 degrees apart with some Loctite should be sufficient. Hopefully I can center it well enough with the set screws that vibration is not an issue. There will also be a rubber flex coupler between the motor and the steering box that came with the intermediate shaft to take care of any minor misalignment.

I'm hoping to get these couplers made up this weekend, so I'll post some pictures of them once complete.

@Ben V I used a Server Power Supply 1300 W / 105A. Actually that one could handle 2 motors but it might be wise to use two units instead because they quickly do a safety shutdown at peaks.
Steering Boxes sound like a good idea but hard to find specs for them. There are many on ebay, I think I will silence the winches instead.

Realizing that my frame dimensions could effect how long my couplers would be, I decided I'd better start on the frame first.

Here is the layout I'm figuring on for my base frame. The steel underneath is 3/16" mild steel plate, bent to be the same height as a 1" square tubing. I'm sure 3/16" is overkill for the application, but the next size down we had in stock at work was 12 ga. At least flex shouldn't be an issue!


I plan to remove the pitman arm from the gear box in the foreground and turn it 180 degrees to match the one in the background, just need to find someone to borrow a puller from. After that, I'll be making a perimeter for the base out of 1" square steel tubing and starting some welding. The pitman arms will be cut down to just under half their current size to increase force.

Also, I purchased hall effect potentiometers that have a range of measurement of 90 degrees, so they should match my steering boxes 93 degrees of travel with no gearing necessary.

I'm hoping that by building a sturdy, separate unit for the 2DOF seat mover part, I could easily reuse the whole assembly in a rig with more degrees of freedom down the road. Alternatively, I may just build an aluminum shell around it to house all the electronics and call it complete.

Im curious @Ben V , just how compact are you looking at. My desk racer is 630mm wide allowing for bolts sticking out and 600mm long. How much thinner are you hoping to go?

@bsft as it sits now, I could potentially keep it at only 500 mm wide, though I'm not sure if that would be stable enough.

Since I don't have a dedicated room for my simulator, and I'd like to be able to use it either with my TV or an Oculus Rift, I wanted the simulator to be somewhat portable. What I've got in mind is to do a long, narrow frame with 2 wheels mounted behind the seat (heavy end) and a handle behind the pedals so that I could pick up one end and roll the simulator around the room by myself.

Yeah I said that at first too but slowly the sim is now taking over a room.

500m wide is not going to be stable. I think mine is around 550mm and if I have a hard crash I have to get out of the sim and re align it to my table. You will also have to re align it every time it starts up because of the force and speed when the sim zeros itself. During racing it will be fine but once the sim starts to bounce around on rough surfaces like the dirt runoffs that's where you will run into trouble.

One suggestion that will keep your sim compact (and not re invent the frame) is to make extender arms like on a crane

@Alexey that's a good point about the high acceleration when the sim zeros itself at startup. I hadn't considered that. At the moment, my favorite racing sim is Dirt Rally, so there will be a great deal of bouncing around.

For prototyping, I think I'll bolt that frame to a couple of wooden boards to stabilize it. Once I've got it moving properly, I'll start on a larger, aluminum frame to enclose that steel one and to hold the steering wheel, pedals, and shifter in place.

@noorbeast looks like a very elegant solution to the portable/stable dilemma that @mazak515 has come up with. I'm not sure I'm feeling up for building something that fancy though.

How big of rubber feet are you using now for your simulator? We've got some 75mm round by 25 mm thick rubber door bumpers at work that I was thinking of using for feet. The rubber isn't particularly grippy, but I was hoping 6 of them would do the trick.

Interesting idea using those steering boxes! What about heat buildup, with fairly low efficiency of about 70% and small lubricant volume? Of course it's not 24/7 application, so I quess that won't be any sort of problem.
Winch speed at full load is rated at 0.8MPM, so motor rpm would be 4320rpm/3.75, about 1150rpm. Divided by your steering box ratio 28:1 gives 41rpm, or 0.68r/s. It should take less than 0.4sec for your 93 degrees of movement at same load.
But torque? Calculating based on winch specs, 33.8mm diameter means 16.9mm leverage for wire, 907kg rated pulling force is about 8900N. So 8900N x 0.0169m = 150Nm at drum. Divided by winch ratio i=153 and quessing 0.8 efficiency gives a bit over 1.2Nm of motor torque. That might be too little! BUT, 1.2Nm at 1150rpm is under 150W of power and winch is rated at 750W.
I'm confused. I quess something doesn't add up regarding those winch specs, as you said earlier. Or my math could be way off...

@Agosky my math came out about the same as yours, so I think the manufacturer just has some confusing specifications. Using the formula Power = Force x Distance / Time (Power = 8900 N x 0.8 m / 60 s) the given full load seems to be 118 W of mechanical output. The winch drum didn't have any bearings, just metal on metal sliding with a bit of grease, so that may contribute to low efficiency. However, I can't see losing that much power as just mechanical losses.

Though the steering boxes don't have very much fluid, they do have a lot of cast iron (They weigh about 8 kg each). I'm hoping that's enough of a heatsink to keep heat buildup from becoming an issue, but I haven't done any loaded testing on them yet.

I've been waiting for a Procar Drifter seat that's been on backorder since June 4, and it's holding up my progress. The seat is supposed to ship to me on Monday, so hopefully I can get back on this project soon. Once it's moving, I'll monitor the temperature of the motors, gearboxes, and motor driver under load and post the results.

Well, my seat has finally arrived, so I'm running short on excuses not to have this thing put together. I got a Procar Drifter seat in grey velour. Here it is pictured with my test pilot and a 5 point Racequip harness.


I welded the frame together using 1" x 1" square steel tubing and 3/16" steel plate bent 90 degrees on each side to stiffen things up.


I think the rubber couplers from the intermediate steering shafts will work out well to join the motors and steering boxes. The steering boxes are mounted on 7/16" threaded rod with nuts on both sides of the 3/16" steel plate so I can adjust the height and angle to align them with the winch motors.


The heim links are size 3/8", and I attached them to the pitman arms by welding bolts into the pitman arms. I drilled a 3/8" hole in each pitman arm, cut the head off a bolt, and plug welded it in place. When plug welding, I had the end of the bolt recessed about halfway through the pitman arm to ensure the weld penetrated sufficiently. I used stover nuts on both sides of the heim link with the beveled side facing inwards to improve the range of motion. To thread the stover nuts on more easily, I first cut the locking part of the threads out with a tap.


For the seat platform, I've got a sheet of 1/8" aluminum bent to form most of a box for stiffening. Under the box, I've got 1 1/2" x 1 1/2" aluminum angle 1/8" thick to carry the weight to the u-joint. Inside the box, I've got 2 pieces of 3/16" thick aluminum angle to bolt the heim links through. Once I get it all welded together, I'm planning to cut some rubber isolators out of 3/16" thick rubber matting to go between the aluminum frame and the fiberglass seat.



The fiberglass seat has a little more flex to it than I expected. The other compact simulators I've looked appear to have the seat only attached by the four bolts at the bottom, but I'm concerned about damaging the fiberglass.

@bsft have you had any problems with your seats flexing too much or any worry of seat damage?

no, seat have been fine and hundreds of people play on them

Thanks @bsft, I'll proceed with that aluminum frame for the seat as planned.