Showroom Senior Design 6DOF platform

I would like to give some background on the project in the first post and following posts will contain details on the project as we proceed. Our school, Montana Tech, requires seniors to create a senior design project over two semesters. Our three man group decided on building a racing simulator. One of the team members used to race outlaw carts, but following his 5th concussion, he agreed to not strap in again. In his time at college and away from racing he got into racing simulation. The desire to take that simulation to the next level is the foundation of this project.
All three of us are mechanical engineering students and so the programming was going to be the part that was beyond out reach. After finding XSimulator, we decided that we could move forward with the project. I have spent a lot of time lurking on the forums and learning all I could. I appreciate the community that this forum has created and hope to make useful contributions. I am sure that we will duplicate many of your efforts to meet course requirements for showing work.
Our project will be broken down into several stages. I hope that these stages can act as a good pathway for people just getting familiar with SimTools. I will be maintaining this blog, a github repository and will be building relevant walk-throughs on instructables.
Right now the basic steps we will go through are:
1: Building an arduino controlled 6DOF platform to learn about XSimulator software and act as a proof of concept.
2: Performing calculations for both the relevant physics and economics.
3: Creating a scale model based on the model from step 1 to validate calculations and practice control systems.
4: Building the full scale simulator and tuning the motion.
5: Writing a report to present for a comity of engineering professors.

@noorbeast
Thank you for the information. We understand that 6DOF is not cheap. Unfortunately we do not know our budget yet because fundraising is part of our assignment. We hope to raise between $2000 and $5000. We may turn in as little as a scale model with PID control and full calculations but our plan is to build a full rig or as much as funding allows. Discounting the parts we already have it seems like the typical arduino/mm build would be around $2000~3000. (If I am off base on that estimate please let me know, I still have a lot to learn and you have clearly been around a while.) We already have the computer, oculus, pedals, shifter, seat and harness. The materials for the frame and shop space have already been donated. We also have access to "free" carbon fiber and carbon fiber winding equipment as well as a full machine shop with lathe, mill, cnc router, cnc plasma cutter, tubing bender and a teammate who knows how to use it all. That leaves power supply, controllers, dampers, and actuators that we need to choose the correct type and size. We will be leaving off sound and air movement for now. The other teammate and I will be using our mechanical component design class to size motors and assess frame geometries. From there we will size everything else.

Thank you for the SketchUp idea. We will implement that for our presentation and for some easy geometry testing. It is unbelievably beneficial to have a free way of testing things. The thread for the servo models is also very helpful.

Regardless of our funding we will continue working on the project. We will fund as much as we can ourselves if we can not fund raise, but progress would be slower. Since this is one of my teammates hobbies and is quickly becoming mine, I expect to spend a lot of time on this forum in the future to maintain this project. Thanks again.

Currently we are working on the arduino/servo test platform. Thanks to @eaorobbie and @aarondc for their awesome work on the arduino sketch to implement serial communication. Once my other teammate returns from vacation I will post the stl files we used to print our model.
Our model was printed on a 3d printer that prints water soluble support material. This allowed us to print holes for the servo retention screws. For that reason, our design will need to be modified before someone else attempts to print it. We are using TowerPro 9g servos and an ArduinoUno R3. Our school lent us a powered breadboard to prototype on.
This is my inexperience showing, while working on the model we experienced an issue with the servos going to their max position when plugged into an external power supply. The power supply, Arduino, and servos must all be connected to a common ground. Adding a jumper from the breadboard's negative node to the Arduino's ground fixed the issue. It is amazing how mental knowledge transfer's so poorly to application. This is why I am glad to have partners to point our my silly mistakes. I hope that nobody else that is jumping straight to 6DOF is that inept.

Sorry to be off the forum for so long. We are currently wrapping up the semester. Our senior design class spent the semester giving us busy work instead of helping us work on our design so we mostly have presentations and timelines to show for all of our work. The other two team members worked up a CAD model of the platform for analysis in one of their classes that I will post once the instructor goes over it. I so far we haven't really learned anything that isn't already somewhere on this forum. I will update again December 12th once our CAD model has been analyzed and will also post videos of the scale model once I pass the minimum post requirement. Right now it looks like we will have enough money for what we intended so a full build will be possible.
The biggest change we have experienced is the move away from a strictly budget build to a build requiring fairly high load capacity because of the weight of the pilot. Next semester we will be purchasing and constructing which will lend itself to incremental updates.

I have attached the 1/8 scale model that we 3d printed. The model was printed on a printer that prints support material, so these files should be edited if anyone else wants to try to print them.
I am still waiting for my teammate to send me the SolidWorks assembly of the model that was tested. I don't think this assembly will be the final design because they were created to be easy to analyze and not to optimize movement. I am still working on understanding the kinematics of a Stewart platform so that I can make a decision about the optimum layout.
A video of one of the teammates running Pikes Peak with the original model can be found here. This video shows that I need to recalibrate the movement profile. The adjustment will be made for the new platform.
If you have any questions about the model, please let me know.

Here is a link to our build video. Sorry to be gone for so long. School deadlines were pretty fiendish this year. I am still working on getting together the spec sheet, cad models, git repository, and some documentation, but I will post them as they are completed. The platform is built and we are in the debugging phase. It works and runs with simtools, but I am still not convinced it is safe to strap into. The beast weighs something like 700 lb, and a glitch made it jump an inch off the ground.

We did not optimize the geometry very well but the range of motion seems to be acceptable. We ended up needing a finalized layout before we could become familiar enough with Stewart platforms to understand how motor positioning effected the ROM. The motors and drivers we chose have encoders built in so we are relying on the divers PID to position the platfom based on a position and direction pulse form the Arduino.

Any questions are welcome. If there is anything you want to know specifically about the platform that I don't get posted with the documentation, I will happily add it. We are planning on continuing this project for several years and probably building more than one platform based on everything we learn.

Great project - congratulations! I am a newbie that is seriously considering building one much like yours. I have watched your videos on Youtube as well.

I had two quick questions and was hoping you could answer them-

1. Did you figure out the glitch that caused this 700 lb machine to leap an inch? As part of my design, I had factored in the need to install a "Panic" emergency shutoff/cutoff button. I'd be curious to know if you figured out what caused the jump, as well as any other issues that may be causing you concern (since it sounds like no one has actually strapped himself in yet).

2. In reference to your comment "...We did not optimize the geometry very well...," given that you've posted Solidworks files, I was wondering if by any chance you built a SolidWorks Simulation (or SimMechanics or Sketchup model)? Essentially I am still trying to figure out how to get to an optimal design. The easiest option is of course to follow blueprints posted on these forums from others' builds. Just wondering what your approach was.

Thanks in advance.

wow.. amazing work!!! look forward to seeing you play your games on ur beast!