Supersonic Flight Simulator

[AndiMe]

The aim of my project was to build a two-seat 2 DOF motion flight simulator. There were some tries using DC-motors but the power is to low and the needed current to high for the weight of two persons. So I decided to go for much more powerful AC servo motors. The further advantage of these motors is, that they has plenty of power to build a fully equipped cockpit and simulate also stormy weather. You can see the basic electronic/electrical setup in the first picture. The numbers in the description written in brackets (for example (1) ) refer to the numbers in the first setup-picture.



1. Mechanical Setup and the Platform

Due to finanical considerations the base of the flight simulator was built by wooden plates. A hook’s joint from a commercial street car was used to allow the tilt motions of the platform in each direction. Due to a lack of knowledge in welding the whole platform (1) and cockpit construction where built by commercially available metal rods which were fixed by a lot of screws. This might not be the best solution in term of weight consideration but has the big adventage to make the construction easily expandable and removable. It turned out that the additional weight is no problem for the motors.



In a next step the cockpit construction was encapsulated with white lacquered compressed wood to avoid the view to the surrounding. This allows a really good simulation of forces because there is no reference of the tilt motions to the surrounding. So tilt motions could be forces as well.



For the cockpit setup commercial office chairs where used as pilot seats. These chairs are easily to mount by 6mm screws through the metal part of the platform. A Saitek Pro Flight Yoke System was mounted to a wooden plate under the three monitors (9). On the pilot’s side a special platform was built for the CHPro pedals. As wideview monitoring system three LG FLATRON L1942T monitors where plugged to a TripleHead2Go box (11). So far I was not able to get 3x HD resolution using the TrippleHead box. I will further work on that.



A stereo sound system was placed over the monitors behind a foam material coerage (12). The subwoofer was placed below the motion platform. In order to have a Cabin-indoor illumination a neon light was mounted at the upper end of the backplane. In this position the light is not reflecting in the monitor during the simulation.

2. Motors, Transmission Unit and Servo Controller.

As Servo Controller a Danaher Motion SERVOSTAR 446M-S was used (5). The motors are two Danaher DBL3H00250-0R2-000-540 AC Servo motors (3): 400V operating voltage, max. 6000 rmp, 1.8 Nm, 1.13 kW or 1.53 hp. In order to get a turning speed of about 1 rmp (what makes sense for flight simulators) a gear reduction was needed. The gear reduction was specially produced for these motors by the company HILBA Antriebstechnik AG in Villmergen (Switzerland) (HILBA gear, Type: P85 / 3, reduction).



Onto the axis of the gearbox self-made aluminium lever was mounted. It only holds by the contact pressure between the axis and the aluminium lever. Therefore it is important to have a very smooth surface in the aluminium hole where the axis is placed into.



To connect the lever with the platform a commercial car steering Hook’s joint was used. This kind of hook’s joints are available in every car garage and pretty cheap.
To avoid damage on the motor and platform it is of great importance to have emergency stop switches (4) on both end of the lever motion range. To make this more professional will be one of the next steps in my project. So far the light switches are working pretty well Two switches per motor are used and a further switch is mounted in the cockpit. The circuit which leads through these five switches is directly connected do the servo controller. There is a separate input for an emergency circuit. If one of these switches interrupt the circuit the servo controller stops the motors at the position they are. The switch inside of the cockpit allows the pilot to stop the motion every time manually and is further very convenient while testing and adjusting the motion values.



3. Voltage Conversion and the Velleman Module

The position value from the steering Software (X-Sim2) is sent to the Velleman Module (7) (Fig. 3.1) which is connected to the USB port of the computer.



This Module converts the digital value to an analogue voltage between 0 and 5V. This voltage tells the Servo Controller how fast to turn the motors and in which direction. Since the input of the Servo Controller is an SPS input which works with a voltage range between -11 and +11 V, the voltage range from the Velleman Module has to be adjusted to the new range by using the circuit (8) in Fig. 3.2.



In conclusion, the motor turns on the one side if the value is negative, on the other side if the value is positive and stops if the value is zero. This value is a dynamic speed value and therefor lets the motors do fast motions as well as slow motions.

I hope I can show you a video of my simulator soon.

If you have questions please feel free to contact me.

Greetings
Andi