The heart of all tests – our cRIO

It is the heart of every single test, actuation or launch within DARE. Our compact RIO. This device, which was sponsored to us by National Instruments, helps us to control, check and measure everything that we need to know from the system at hand; And it is in need of an upgrade.

The minor of 2017-2018, also known as Project Hummingbird, is currently working on developing a thrust vectoring control mechanism. In order to properly test this system, as well as to take measurements, an upgrade for the cRIO is needed.

Me, taking measurements on the current cRIO.

For the trust vectoring minor we need to do a few adjustments to the cRIO box. The current setup only allows actuation of solenoids to completely open and close valves. Until now no other type of actuators was needed. To do trust vectoring we will need servo motors. The cRio needs to generate signals for these servo motors to go to the rotation of our control output. To do this an extra module is needed for the cRIO that can generate so-called PWM signals. Also, we need an additional external power supply at the correct voltage to power those servo motors. And last we need to make connectors and do the wiring inside our cRIO box to connect the new servo motors.

The cryo team needs different solenoids to actuate their valves. These new solenoids operate at 24V instead of 12V. This means that an extra power supply is needed and the relays in the box have to be connected to this new higher voltage power supply. Because we have multiple teams working with their own solenoids a solution has to be found to that not every time the box has to be rewired and also that other teams don’t accidentally destroy their solenoids by connecting it to the wrong voltage. The safest and easiest way to do this is having a different connector size for the two different voltages and have added more relays to the box to accommodate the extra connectors. Unfortunately, there is not enough space left in the box to do this so we have to be a bit more creative with the wiring. By adding one extra large relay to switch between 12V and 24V it is possible to switch between voltages. To make sure 12V solenoids are not connected to 24V volt the off mode of the relay sets it into the 12V mode. To set the relay to the other mode both a digital output in our software must be set and also a physical switch must be flipped to go into 24V mode. Redundant security measures are always good practice when it comes to human errors!