New Motion Sim Project Using AMC

Hi Chris,

I really don't understand what do you mean. DIY doesn't necessary mean that you should have access to the source code of a software or a microcontroller also... Take a look around and you will see that most DIY projects work the same way. Its probably the only way to prevent large corporations from stealing all the hard work we have done, and shared for free with all you.

Another reason for not just giving the source code is that most people here doesn't have the compiler needed or the knowledge to even alter the code without disastrous results to their simulators...! The compiled firmware, on the other hand, is tested and can be loaded using simple programmers (like ponyprog) or even more professional ones, like the STK500 AVRISP...

About steppers... The only stepper actuator I ever seen to actually work as it should, is the SCN5! But yet only 10kgf max out of it!!! Go ahead and waste your money trying to make it work, but I doubt. Hey, here is another one: Try to make a stepper to accelerate!! :brows:

AC motors with VFD servo amplifiers are the best choice for motion simulators. There are several ways to drive them, Voltage -10 to +10v, PWM signals, or even serial RS485 with several protocols. And many have inverters that produce 3phase from just 1phase so it can be used in most home enviroment too. Too bad that we cannot afford them yet!

About ready commercial solutions that fit for motion control... They just not exist! I was looking for something cheap to use instead of making the AMC and had found nothing at that time. When we had to search for commercial motor driver solution, the 24V motors was not supported by the cheap ones, so I designed my DSMhb mosfet h-bridge... Its all made from necessity for something better and cheap in same time. Otherwise I could have stop when I had made the commercial BS2 board and commercial HB-25 work for my motion simulator.

Don't get me wrong. we have spend years of research and testing so we know what works and what doesn't...

Regards, Thanos


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Great reply Thanos, I agree with you 100%
That is why I am trying to follow all the expert 'instructions' from this website.. if I wanted a commercial solution I would go to Frex.com and buy their products ready to be used.

I think that there are a lot of complex issues to follow while you build your sim with Thanos boards, so why bring more complex issues to the project??

On my forum post, someone wrote have you tried to stop your car wipers with your hand?, I am just imagining that the 24V will be even stronger, I am sure they will do the job.

I will keep researching on this website, next step will be getting the motor to work and learning a little more about the pot, while my boards are not ready.

Lamealot, do you have your structure layout already built (Seat, wheel and pedal support)?
I am paying around 300US$ for all three boards (AVR, H-Bridge and LCD), I think it will be worth in the end.
Aloha
Caue

Jsut going back to the 'off the shelf idea' for a moment, here is a project board based on the ATMEGA8 16PI as is the AMC board. http://www.futurlec.com/ATMega8_Educational_Technical.shtml

Surely Thanos' firmware would run on this for the logic? (chop the crystal). It is $35!!!!! :yippiee:

Chris

ATmega8 chip is not the same as ATmega8535.

Also ATmega8535L-8PU is not the same as ATmega8535-16PU...!

And those boards you link to, have very small crystal on them, 4Mhz or 8Mhz in best case, that is cannot synchronize to the 115200bps serial speed without large error ratio. The perfect crystal for 115200bps serial speed with zero errors is 22.1184Mhz !!!

My firmware can run only on ATmega8535-16PU and ATmega644-20PU and only with the pin designations that exist only on the AMC1.5 board...


Regards, Thanos

has anyone ever thought about using an accelerometer setup to feedback position data instead of potentiometers? My gps tracker board that i showed off earlier in the thread is currently being modified to include x/y position sensors so that my display software can be used in real aircraft ,but i have a theory that the x/y data reported over serial could also be used for position feedback in a motion simulator. Look how small an accelerometer circuit can be and easy to implement! Is this fresh thinking or dumb?

Chris

It could be use only on 2DOF, but what i know its allways better have senzor closer to motors (in mechanical way (less backslah )).

It doesn't work with accelerometers... These devices measure with great precision static angles, but not during the actual rotation action!!! During the rotation their sensor thinks that is free falling, and outputs just zero's...

Since all motion simulators do perform rotation in order to simulate a axis movement, the proper measurement device is the Gyroscope. But these are drifting after a while, so they work in conjunction with accelerometers to recalibrate when in level position again.

Generally accelerometers and gyroscopes aren't supposed to be used as primary position detection method cause they are kind of unstable from their nature.A better job for them is to used a secondary sensors over the main one's to do some statistical calculation or automate calibration of the motors, etc...




Regards, Thanos