How does a force feedback steering wheel work?

[berlincam86]

Can someone please explain in detail how this works?  know there is a motor in there but how does it simulate hitting another car or wall. Does it pulse the voltage to the motor? How many volts does it pulse? how come it doesnt pull the steering wheel out of your hands when it activates?

[SavannahLion]

I've only dabbled on the PC side of things. I had a passing interest in it for about... six months, I guess about ten years ago, when it was all the rage. I figure arcade systems are similar in function but not design. The principle remains the same though.

It's part of the game code. So it's not like you can simply plug in a force feedback steering wheel into just about any game and expect it to work. Sadly, modern PC games tend to lack feedback support because of some inane patents held by a patent holding company. ---smurfing--- technology have been around for yonkers and they manage to get some key patents. 

I digress. Code supports it, hardware supports it, motor receives a signal and responds accordingly. I can't recall if it's just a simple motor or a stepper motor though. I want to say there are systems that use both, but I'm just recalling some vague designs. Never researched the voltage. For safety reasons most steering wheels don't rip out of your hands. Technically I think it's more to do with the available torque of the motor, but that doesn't say high torque steering wheels don't exist. I've played a few games that literally snap your wrists and shake the fillings lose from your teeth from the force feedback.

How detailed do you want to get? What are you trying to do? Rebuild a steering wheel? Build your own wheel from scratch? Write a new game? What?

[berlincam86]

Well that helped a little. This is what im doing. I have a old sega rally championship sitdown driving cabinet. I got it empty for $50 so I couldnt pass it up. I put a monitor in it and a steering control panel that has the force feedback stuff in it. I also got a couple of game boards. I got cruisin world and offroad challange both games are force feedback games that use a steering wheel feedback control board. The problem that I have is the steering setup I have now is differant from the one that was in the games originally. So im wondering how to hook it up. In the setup I have now there are two things there is the motor which runs at 100 volts. then there is a clutch that runs at 24 volts DC. In the setup that was for those games that I have there is only one motor that I think runs at 90 volts. The motor in my cabinet now Is directly connected to the steering wheel by a belt. when there is no power applied to the clutch the motor can run and not move the steering wheel. But when power is applied to the clutch then the motor can move the wheel. It is not a stepper motor. So im guessing that the control board pulses the voltage to the motor in the games that I have. But I have seen these motors and there is some slip between the motor and the wheel. Mine does not have any slip. I dont know if I confused you  but I sure am. Im just trying to figure a way to hook this up. If I hook up the motor to 100 volts  and the clutch to the control board the motor will run all the time. I was thinking of putting a relay or something in so that when the board gives the signal it will activate the motor and the clutch at the same time. As much info I can get would be great. I hope someone can understand this.

[D_Zoot]

I've seen various methods used over the years, but usually it's setup like this-

The game board provides some manner of digital signal to a driver board.  The driver board interprets the signal and supplies the feedback motor with pulse width modulated voltage.  By varying the length of the pulse, the amount of torque the motor generates can be varied.

Pulse width modulated schemes seem to be the most efficient in these types of applicationss due to the ability to control the motors torque while keeping heat in the motor down.  Supplying straight AC or DC current to the motor (depending on it's requirements) would quickly heat the windings (and brushes if it's a brush motor) since the motor doesn't actually spin around.

I'm not familiar with the setup in your Sega machine, so I can't offer any advise as to how to utilize it in any other application.  I suspect however, that simply turning it on/off by shooting 90v to the motor with a relay will result in a rather harsh/abrupt and potentially violent feel to the feedback system.


D

[berlincam86]

ok that makes sense.

[SavannahLion]

Ok, I understand now. I was thinking you were building your own cab, not refurb an existing one with existing boards.

I don't have Cruisin, but I did just recently obtain a board I know to be an Off Road game. Don't quite recall if it's Midway's Challenge or Leland's Ironman (Did Super Off Road even have feedback ). I would probably start by pulling the instructions/schematics and see what I can learn there. Have you done that yet?

[berlincam86]

Yes I am trying to resurect this cabinet. The  ivan stewarts ironman super offroad did not have force feedback. They had 3-360 wheels and thats it.  I have the schematics and all it has is an output for the motor off the steering control board. I wouldnt be able to wire that just to the motor. The clutch is my problem. I dont think i want it on all the time. it might burn it out. Im trying to figure out how i could do it so that when the motor is activated it activates the clutch at the same time.

[SavannahLion]

Im trying to figure out how i could do it so that when the motor is activated it activates the clutch at the same time.

If I'm following this well enough....

What about losing the clutch. Then you can shorten the belt...

or move the motor to apply the appropriate tension to the belt

or add a spring loaded tensioner in place of the clutch?

It would all depend on how the steering wheel you have is currently constructed.

[berlincam86]

Now there is an idea Wish i would of thought of it. Im gonna take this control panel off and see if i can get a picture.

[berlincam86]

Here is one.

[berlincam86]

Here is another. The motor on the left is the feedback motor. the thing on the right is the clutch.

[SavannahLion]

Hhmm.... isn't quite like how I visualized it. How does that clutch work?

[berlincam86]

The belt from the motor goes to the clutch so if the motors on it just spins ant the clutch. when the clutch is activated it moves the belt to the wheel.

[SavannahLion]

The belt from the motor goes to the clutch so if the motors on it just spins ant the clutch. when the clutch is activated it moves the belt to the wheel.

So what you're saying is.... It's a solenoid which pulls the small gear in towards the larger gear?

Hhmm... It's really hard to offer suggestions without having the assembly in my grubby hands.

Might be some way to permanently set the solenoid in the "closed" position. Like a place for a cobble pin or adjust the small gear accordingly. You might even be able to Macgyver it a bit with a suitable washer and a carefully placed blob of solder. That might ruin the solenoid if you ever desire to reverse the modifications or the solder might not be strong to hold to the abuse. Maybe one of those locking collars with a drop of loc-tite instead of solder? Would be a PITA to find a fitting collar though. Might find something that would fit in a well equipped store that sells steel cable.

Another way, but it might be a little more work, would be to see if you can adjust the big main gear on the steering wheel along the shaft so the teeth fall in line with the belt between motor and clutch. Can't tell if the bolts would get in the way of this though. If you can do that, then you might be able to remove the large belt and use the belt for the clutch/steering instead, bypassing the clutch entirely. The motor looks like you can adjust tension on the belt and there might be enough play there to get the right tension on the small belt. The immediate problem that I can see is that you've effectively doubled the speed of the motor by bypassing the reduction gears of the clutch.

I'm kind of running out of suggestions that don't require fabricating whole new asssemblies.

I'll chew it over a little while longer.

Is it possible to snap a photo of the clutch in the engaged position? I think I know what it does, but I just want to be certain.