Motion system with FSBus and servos

[Guest Ceawlin BSX029]

Here's another for you guys and gals out there to scratch your heads over....Having trawled through the FSBus stuff, it would appear feasible to implement some form of motion platform using either servos or steppers. The questions I now want to ask are as follows:Are servo motors actuated in a similar way to stepper motors, and if not, how does one know how far the motor has turned before it is required to stop?Are there any decently powerful stepper motors that are relatively cheap that can be used in place of a servo motor if the servo motor is not deemed accurate enough for specific rotations?What's the best way to increase the voltage output from an FSBus board to the motor? We're talking somewhere along the lines of 9-12v to something like 220-240v, although 110v may well suffice. I'd like to be careful here as I do not want to suddenly end up with a piece of toast as a circuit board :-doh And is there a function in FSBus that reports the up/down motion of the aircraft? I noticed there is a pitch/bank that can be scaled down for motion platform suitability.....Anything else I've forgotten I'll ask later on, got too much of a headache from all this sim planning stuff!

[Guest dakenskys]

Hi,Actually, the reverse is true...Servos are better suited than stepper motors. Servo motors are basically a geared down motor with enough torque to move a control surface. These servos have a feedback circuit that allows it to move and "know" it's relative position at any time. You would run the servos with it's own power supply and control it with what is called a pulse width modulation. Take a look at this site: www.fursuit.org/faq/servo.htmwhich has a good explanation of servo operation.Stepper motors usually don't have a feedback circuit unless added separately, but they rely on counting pulses. If the stepper is stalled for inadequate torque or other reasons, you would lose your reference point.Check these other sites for more detailed explanations of servos:www.brookshiresoftware.com/how_sscs_work.htmwww.cpg1.freeserve.co.uk/servos/servos.htmwww.rentron.com/serialservo.htmBest regards,Kenwww.DakenSkys.com

[Guest rolandvanroy]

convert FSbus servo drive to PWM seems best choice. see the other post in motion chair. A power servo amp with feedback from potmeter connected to platform will close the loop. But first we need to know whether FSbus can deliver the right parameters with the required speed. Roland

[tigert]

>convert FSbus servo drive to PWM seems best choice. see the>other post in motion chair. A power servo amp with feedback>from potmeter connected to platform will close the loop. >But first we need to know whether FSbus can deliver the right>parameters with the required speed. >>Roland I would guess one needs to do a custom software solution for this since FSBUS doesnt do any washout stuff for the motion. Just tilting the platform according to the plane attitude makes you feel like the artificial horizon instead of feeling the motion forces - there are mainly senses of acceleration and deceleration that are important and which are not taken into account if one just simply translates the plane attitude to the motion platform tilt.Tuomas