RaguTom's Build - 6DOF on a budget!

Hello Everyone,

I'm new to the DIY motion scene, but not necessarily new to motion simulation. I have worked on a few arcade machines that utilized motion simulation in some way, but haven't searched as deep as I plan to now.

I'm interested in starting small and working my way up. I am an electronics engineer/technician by trade and very used to working with many different types of circuits. I am an OK MicroC coder, and very interested to see if I can interface a PIC with SimTools. I know, some of you are saying....why not just use an Arduino....there's already sample code for it and many built-in interface options. That's too easy! This isn't just a fun project, this is a learning step as well. There are always ways to take what someone else has done and refine it for yourself; but, there is another level of satisfaction knowing you started from scratch.

I'm not planning to have a full motion simulator by tomorrow. I plan to take this on over a few months or so. I can't wait to talk to everyone here! I can see there is a wealth of information floating around here, and everyone seems eager to help.

I am located near Harrisburg, Pennsylvania and if anyone else is near by, I'd love to network!

Tom

'Too easy' . Welcome, good luck with your project.

Already made good headway today!

No doubts here that you can interface a PIC with Simtools. Code is or was available here already for use with Picaxe chips. Their basic interface makes them to slow for anything other than PI motor control though. However, the Pololu Jrk motor controller that some here use are based on the PIC18F14K50 and have full PID control. If you could emulate what Pololu has done with their code, and would be willing to sell programmed chips for $5 to $10 (considering you can purchase them for around $2), it would for sure be a big hit with some members here that would just prefer to make their own and save some $.

ps It would also be awesome to make your own "Jrks" capable of 30-60amps or more!

Thanks for the support guys!
Any time I work on a project from scratch, I don't design it for just myself, even if it ends up just being for myself. I think about the numerous ways it could be utilized by the public, and design it around that. As an example, my last project didn't need to have user configurable names on the 4dgl lcd panel, but it did.... just in case.

Alright everyone!!! Hit the ground running. Looking for the best thread to move this into now that it has become a serious project. The board design we went with is a 6 motor driver with full H-bridge for each motor, and instantaneous braking. Everything is optically isolated. It also has WiFi and USB for connecting to SimTools and for updates. Each H-bridge has it's own power supply input, meaning grab 6 cheap computer power supplies (assuming 12 volts in this case) and you have yourself a serious amperage mover. Keep in mind, a 600 watt PSU can push 50 amps at 12 volts The board has 24 FETS on it!! Best part....JRK be damned....This board can be produced for under $100....that's right....6 drivers for under $100 It has analog inputs for feedback, digital inputs for buttons and optical feedback, and digital outputs for driving LED, fans, etc. This board can also be used for robotics (which is the final goal for this board) or anything else that needs precision drive with high amps. the H-bridges can also be used as high amp digital outputs (full on, full off)

So... how's that for awesomeness???

Where should I post to next?

Any suggestions for features

Tom

I'll also add that the analogs can also be used for gradient type optical feedback. We are also working out a remote 9 axis gyroscope that can be mounted to the platform to ELIMINATE direct feedback. No more pots, no more optical feedback, if you wish! The sensing is so accurate, it can reliably be used as "limit switches" and precision feedback to the controller.

Hi RaguTom. This could be great solution for an easy to implement 6dof motor driver once you get a gyro working!

You didn’t mention anything about its PID controller(s) though. Most people here that use JRK’s like them because they say they have excellent PID control. Simtools itself does not do PID control.

PID is taken care of on the processor on the board. It is a PIC micro. We have a PID program that is currently used on many Onan generators around the world for throttle control. We have tested this on a breadboard for this application with one motor so far and had excellent results. We utilized a wiper motor for motion and SimTools to generate the numbers for us.
I cant wait!!! i'm really excited about this coming together!

Tom

Done

How about an interface that will allow the PID perimeters to be adjusted?

If we could program a PIC ourselves from a computer like we can an Arduino we could just hard code changes and reprogram if necessary. But since most people won't have a PIC programmer, the PID settings need to be user adjustable to allow for different rig configurations, etc.

Thanks!

Thank you for moving this!

Adjustments will be done from the PC, either over USB or WiFi (dependent on how you are using the controller) It would be nice to throw a CrystalFontz character LCD on it for adjustment right on the board, but i'm thinking of final cost, amount on pins on the processor, and the final installation locations of these boards. It is still a possibility, and there is a good chance we will give the option.

The PID program that is already written has the ability to have on the fly adjustment for the PID values. I have a list of 28 registers that can be read or written to for all different parameters, such as calculated RPM, calculated load, position of drives, temperature input, and temperature alarm.

We will be refining the existing program PID routine to accommodate Sim motion and robotics. The PC program for this application will most likely be written in .NET with simulation in mind. We already have a PC program to adjust the registers, but it is written in flash and geared towards throttle control.

Tom

what about the costs??? a jrk card to control one motor cost around 100 usds... what do you think it would cost doing it using the pics?

best regards
fer

All parts on the board, the production of the board itself, and the wifi module is under $100. Hard to believe because of what things like this cost, but trust me... all consumer electronics are severely marked up.

The FETS are dirt cheap, the optos are cheap, the resistors are fractions of a cent each, the connectors might be the most expensive parts, the board manufacturing itself is $40 for a prototype under a certain size, which means its even cheaper in production.

Tom

Is there any possibility to control ESC/brushless motors also? Would be great...
Thanks!

The H-Bridges are variable duty cycle, so technically full speed control should be available in its current state.

If direction control is not needed, the 6 H-Bridges can actually be used to drive 12 motors in one direction only with full speed control. Not extremely useful for your main drive motors in Sim world, but some use could be conceived. Obviously, at that point, SimTools would not be the interface program anymore and you would need a different program to write to the registers. This info will all be available for free, once fully documented.

Used in a different application, the instantaneous braking through the H Bridge could be useful for something as well. Haven't really thought of a great purpose for it yet, but it is there should it be needed!

Hope this helps!

Thanks
So @RaguTom is not easy to implement brushless support? Just to know, because there are great brushless motors and they are easy to get also.