Coming soon: Full motion simulator writeup
This project has been in the works for about 4 years. It’s a single seat, full motion flight simulator. I’ve just got a webcam setup so I can capture it in action. Unfortunately I captured a fairly unsuccessful flight from Heathrow to London City that ends up overshooting the runway.
The actuators and motion control software are all DIY and I plan to open source the design.
Frame
The frame is all welded up from steel box section in multiple sections so that it’s somewhat portable. The lovely red powdercoat was done by PowderPlus. The control mount section at the front is still a wooden mock-up that I will re-make out of steel at some point.
Actuators
The actuators are built around a chassis made from laser cut and CNC folded sheet steel (by Ceandess) and steel tubing. The power comes from a cheap 24V DC brushed motor (as used in Chinese electric scooters) which drives a 16mm ball screw via a chain. An incremental optical encoder tracks the position of the ball screw. The electronics are all custom: a motor driver and an STM32 microcontroller. The motor driver is a discrete power MOSFET H-bridge and has current/voltage monitoring and a braking resistor to dump regen current. The STM32 has a CAN transceiver and all of the actuators sit on a CAN bus which is used for position, status updates and programming PID coefficients, current limits etc. This design means only four wires are needed for all the actuators: VCC, GND, CANH and CANL. I had to put a lot of work into making the actuator robust as the motor is powerful enough to tear the thing apart and the currents/voltages flying around can easily blow up the electronics.
VR
The VR setup is a stock HTC Vive. I have one of the Vive controllers fixed to the seat behind my head which is used to subtract movements of the platform with the OpenVR Input Emulator software. Availability of motion cancellation was my main reason for choosing the Vive setup.
Simulator
The simulator software is unmodified XPlane 11. XPlane has great VR integration and provides the data I need to drive the motion platform via UDP.
Motion control
I ended up writing my own software that implements the classical Reed/Nahon motion cueing. It also has a fairly crude graphical display that shows the position/health of each actuator and the position of the platform. The Reed/Nahon algorithm has lots of coefficients that need to be tuned and I still have some work to do on this.