This is a senior design project in Mechanical Engineering at San Jose State University. Check the “Who We Are” tab above for more information about the team.
Our goal is to build a 6 degree-of-freedom motion platform for racing simulation. We believe the most elegant way to achieve this is through the use of a robotic configuration called a Stewart platform, first used by Eric Gough in 1954 and later published by D Stewart in 1965. A Stewart platform consists of six independently controlled linear actuators, all mounted to a fixed base and the movable platform. By independently controlling the length of each actuator based on some very complex math, the platform can precisely move with 6 degrees of freedom (forward/back, left/right, up/down, and rotation about each axis). This is ideal for motion simulation as it provides a much more realistic experience of using different sizes of roller screw actuators than the typical 2 or 3 DOF simulator. Watch the video below for an idea of what a 6 DOF Stewart platform can do:
Our project is based on a variation of the Stewart platform that uses rotary actuators rather than linear actuators. We built a small Arduino-powered prototype to help us better understand the geometry and mathematics involved in making it the platform move where we want (check the home page for a video of it in action!). Aside from the physical construction of the platform and the complex mathemathics involved with driving the actuators, the other key step is to setup an interface between the control electronics and the software used for simulation which we use the best application development tools to work it out. To accomplish this we are using an open source program call X-sim that was created by the DIY motion simulation community for just this purpose. It will extract the acceleration data coming from the racing game and interpret it to determine what position the platform should be in to accurately simulate the current g-forces. That position then gets fed into our controller which determines the position each of the six actuators needs to be in to locate the platform as dictated by X-sim. And all of this happens 50 times a second!
What this means is that whoever is driving on top of that platform is going to FEEL like they’re in the car. This is what motion simulation is all about and why we can’t wait to experience it!