The gimbal measurement system

Hej everyone, this is Jack !

At the end of april me and a group of six other students started to help B2D2 with the three axis measurement system, henceforth referred to as the gimbal.

The gimbal is a tool used to test various movements in 3D space, since it is able to determine the angle of all three axes. In our case it was designed to test the ADCS used to rotate our FFUs camera away from the sun during the experiment.

The first version was just a frame and worked as a reference to understand how it would look as a finished product.

First version of the gimbal

The measurement system itself started with two similar ideas.

The first one was using prefabricated codewheels/decoders placed on each of the frames.This kind of device reads the angle of the shaft connected to the frame it sits on.

Codewheel/decoder

The second idea went through more trial and tribulation. There was nothing prefabricated available online which was both more exciting but also made it more difficult to deal with.

The idea was that a distance sensor would be pointed at a spiral on the shaft. When the spiral rotates, the distance between the sensor and the spiral changes depending on how much it has turned. By reading the distance, we are thus able to read the angle.

First version of the distance sensor/spiral

The first version above was crudely made with a 3D printer and wooden spiral and worked as a very basic prototype to do further testing. After plenty of testing with both of these systems we were ready to make a first draft of the final version of both.

First draft of the final system

Our first version was 3D printed and only the distance sensor/spiral could fit on it. For our final version, the part that holds everything together was made in a CNC machine and both the codewheel/encoder and spiral/distance sensor fit on the same part.

With what we learnt from making that part, we were finally able to make an actual final version that we put on each frame of the gimbal.

Final version mounted on one of the frames

Now it is wired up and ready to be used to measure angles on the gimbal!

Jack