2DOF Compact Seat Mover Using Winch Motors and Steering Boxes

For my first motion simulator project, I've decided to keep it simple with a 2DOF seat mover. I've drawn inspiration from many of the builds on this site over the last few weeks, and I'm now ready to begin my own racing simulator project.

As I do not have a dedicated room for the simulator, I'd like to keep it fairly compact and easy to move. Here is my first concept drawing for a layout.


So far, the parts I've collected are:
- 2 Superwinch LT2000s for motors
- 2 Steering boxes from '85 Chevrolet S10 for gearing (28:1 ratio)
- Rear driveshaft from '00 Dodge Dakota for universal joint

I've ordered:
- Kangaroo x2 Motion Controller
- Sabertooth 2x60 Motor Driver

I plan to use:
- Fiberglass or plastic racing seat (Still looking for a supplier that isn't too expensive to ship to Canada, I only budgeted $300 for the seat)
- 4 Point harness attached with springs similar to the CXC simulators
- Heim links to connect steering boxes to seat frame
- Hall effect potentiometers
- Oculus Rift (Waiting for the consumer version)
- Buttkicker Gamer 2 or Buttkicker mini LFE

I'm planning to complete the build in 3 stages:
1. Build a working full-scale prototype to learn how to use SimTools and the various hardware
2. Refine the prototype trying to condense everything into the smallest package possible and build a more aesthetically pleasing version
3. Add another frame to hold the steering wheel/pedals/shifter that is adjustable for drivers of different heights

http://www.xsimulator.net/community/threads/desk-racer-2dof.5326/

http://www.xsimulator.net/community/faq/adjustable-draw-slide-pedals.93/

That's a nice, compact simulator @bsft. I saw in your build thread that you used 40mm center-to-center arms on your gearboxes. Do you use a full 180 degrees of travel when you're running the simulator (80mm total movement)? I'm trying to use short arms and run my motors at a higher speed to maximize efficiency, but I'm not sure how far my seat needs to move for a good racing simulation.

From memory, I think I only use 65mm of travel up and down, so thats not 180 deg, maybe 130? I dont know. I use 40mm CTC levers. It seems to be enough. The desk racer has 17 deg total angle surge, but 7 deg sway, so I adjust the profiles to compensate so it feels the same.
You dont need big movements for simulation, once you have a good solid profile set, you will get the immersion.
Its like that stupid video of the guy on the force dynamics 401 playing F1, with maximum throw, people think thats realistic. Wrong!
Even force dynamics themselves have that amount of throw on the sim, but its for flight. A good race sim is short and sharp.

@bsft my steering boxes max out at 93 degrees total travel on the output shaft, so I'm thinking if I drill some new holes in the pitman arms 50mm from the center of the shaft, that should give me 72 mm of total travel.

Just tested the mechanical output of the winch motor/steering box combo using a breaker bar and a fish scale. I feel like this rig needs a bit of duct tape to complete the look lol.


Results are 19.2 kg at 0.393 m from the center of the shaft.

After a little math, that means my output torque is 73.9 Nm. My output force on a 50mm arm would be 151 kg for each actuator. I'm pretty happy with that!

@noorbeast the specifications on the Superwinch website state that it is a 750W motor. I tried to work backwards from their output specifications based on rated line pull, rated speed, gear ratio, and drum diameter to figure out the motor torque and speed, but the numbers just weren't working out for me. Instead, I disassembled the winch and took some measurements of my own.

By my own measurements, the stall torque is 3.5 Nm and the free speed is 4420 rpm. I measured output torque with one of those bending beam style torque wrenches (I have a nice little 1/4" one that worked perfectly), and I measured the output speed at no load with a photo tachometer. Both measurements were done using jumper cables from my truck battery as the power source and a 12V contactor I had laying around.


Putting 3.5 Nm of torque into a 28:1 gearbox and getting 74 Nm out at the other end, I figure these steering boxes are about 75% efficient at transferring torque. Replacing the lubricant in the steering boxes might improve that number somewhat too.

@noorbeast since the steering box is a ball screw assembly, the output shaft can only move in a range of 93 degrees. It moves so quickly from lock to lock that I'm not sure I can accurately measure the speed.

I checked the ratio by counting revolutions of the input shaft and using a magnetic angle gauge on the output arm. Input moved 7.25 turns or 2600 degrees; output moved 93 degrees. That gave me a ratio of 28:1.


Inspiration to use winch motors came from @Pit 's build. They cost me $90 CAD each brand new, and they are available at many local stores. The steering boxes cost $60 CAD each from a local auto wrecker.

hi all thank you very much for your efforts. At the moment I can't dissamble my winches for testing with. IMO this type of winches seems to be all the same.

I did get 2 winch motors as well, they just arrived today so I had no time yet to inspect them but they were kinda cheap:

http://www.ebay.de/itm/141458997453?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT

I did get two for 105,98 EUR

Now the price is little higher though. With my calculations these should do about 50rpm but I may be wrong.
Anyone ever tried to run one of these above 12V ?

Weird, can´t see noorbeasts reply here but in mail... anyway I thought I read somewhere the winch does 5m/per minute so thats why I calced the 50rpm.
The truth is probably somewhere below. Plus you have to calc the width of the rope that increases the diameter of the drum. So yes, 30 rpm sound more realistic but I will test tomorrow.

Hi @xytras my winches do ~3m/min and ~23 rpm. There exist faster winches - but most of them need more power - too much for the PSUs, motor drivers etc.

Hmm yes true, that would require some Vyper motor driver or comparable... bit too expensive. With that cost it would probably a better choice to switch to AC motors.
The MotoMonster goes up to 16V but is limited to 30A peak, I see you did a lot of experiments with it already. Question is if 16V vs 12V do much difference.
It probably just increases the heat produced.

It is like a bulb - more V = lighter (= faster) = blowing
You could stick 6 MMs in a row - if needed (180A current, 360A peak) to drive any Godzilla monster winches...

@noorbeast the drum diameter for my winch is 31.8 mm and the wire rope diameter is 4 mm. The rated speed at 0 load is 3.0 MPM. Figuring on the effective diameter being the drum plus half the wire rope on each side, that would give 33.8 mm. Multiplying by pi then gives a circumference of 106.2 mm. If each revolution pulls in 106.2 mm and it moves 3 meters in one minute, that gives a rotational speed of 28.2 rpm. Multiply that by the gear ratio of 153:1, and the motor speed should be 4320 rpm.

I disassembled my winches before measuring the output speed accurately, but I think the manufacturer's specifications reinforce that my measured rpm of the motor was fairly accurate at 4420 rpm. I would have had somewhat less load because the gear train and drum was completely removed when I was testing.

@xytras I haven't tried to run a winch motor at higher than 12V, but I expect you could get away with being somewhat overvoltage.

In normal applications, applying 24V to a 12V permanent magnet (PM) dc motor will: Increase your starting torque (stronger magnetic field generated); about double your starting current (Voltage / Resistance = Current); and, nearly double your top speed (the greatest speed limiting factor in a PM motor is counter-EMF produced by the motor acting as a generator. When the counter-EMF reaches the applied Voltage, the motor stops accelerating).

The additional current through the motor produces more heat, but you also get more power output. You may be able to increase airflow enough to cool the motor, but keep in mind that it's the windings in the middle of the motor that need the cooling more so than the magnets on the outside attached to the case.

The part I would be most concerned about is the increase in top speed. If you run a motor designed for 4400 rpm at 8000 rpm, there's a good chance that either the motor will vibrate itself apart, or the centripetal acceleration will pull the armature apart.


However, in a simulator application, you're not really running your motor at 12V, 24V, or 16V. You're running the motor on a variable voltage between 0 and source voltage (0-12V or 0-24V) and constantly inverting the voltage to reverse the motor. The motor has short periods of high current flow, then has a little time to cool off before the next quick burst of current.

For this reason, I imagine you could get away with running higher voltages to a 12V motor to get a little more power out of it. You don't need the power very long, so the armature can cool off in between bursts of current and the motor would not be accelerated way above it's designed top speed.

I haven't played with SimTools yet, but someone more experienced could probably help you tune it so that your motor driver never applies full voltage to the motor. That way you could use a 24V supply and test your 12V motor at 14V, 16V, or 18V.

@Ben V yes but on the other hand DC motors don´t like the instant direction switching. With a $60 motor it is a minor risk to test this but as the motors are stressed anyway I wouldn´t go above 15 or 16V also because MotoMonsters limit is at 16V.

Usually these motors are not constructed at their limits, the question is if it is worth risking it. Some cooling fins and airflow and it might work but for 2 or 3 more rpm it isn´t worth the attempt.

Okay here we go with some first impressions of my winch motors

1. In continuous motion the winches are loud as f***! I wouldn´t use them without ear protection or without putting them into noise isolation.
2. Instant direction change knocks out the power supply. I am not quite sure how @Pit solved this but probably the MotoMonster got a good Back EMF protection? Otherwise I´d add a Back EMF protection circuit.
3. It runs at 32 rpm in neutral. (Check out the video if you want to count for yourself, I made a marker on the drum )