Two days left before depature. We may consider finishing our climber and pack everything together. But first of all we need some clothing for the freezing cold japanese winter (technically its warmer in Mito than in Munich). So we got ourselves some sweaters from C&A and foil (yes black, as always) and manufactured them.
Since we now don’t have to freeze anymore, we can get to the more important things like logos and stickers on the climber, the suitcase and everything else lying around.
And we still had some time left to lasercut the foam of the suitcase to fit the shape of the climber. (Pro tip: don’t smell the foam after lasercutting it. Is smells horrible!)
5 Days left until the first day of the competition: Since we are professional eningeners we developed our electronic way ahead of the competition to have enought room for failiure. Just kidding: Time to finish our new PCB for the electronics we ordered 3 days ago.
After houres of combing and sorting cables we finished the wiring (All cables are grey because we ran out of black wire, so Bürlin, please give us some of the awesome LIFY wires you have, but we don’t want to pay them). To make it durable against dirt, weather and mostly us we need a case for it. Its a 3d printed, well overengineered PLA box, black of course.
You may wonder where we put all these cables. Thats the reason why there is no picture with all wires inside the box.
Another paragraph of the SPEC Rulebook says: „Cover up moving parts and sharp edges“ as well as „the climber should not land on the batteries when falling“. Apart from the other, slightly bigger problems when the climber falls off the rope, we will cover up the whole upper part with a big canopy made out of vacuum formed ABS. The shape was stolen from the Siemens Taurus locomotive due to time issues (sorry Siemens, no time to ask for permission). Since we couldn’t find a better way to produce a heat resistent positive mold, we just made ours out of wood.
After we recieved the ABS and PS sheets with one week delay because the supplyer wasn’t able to tell us they sold stuff they don’t have we finally were able to form the canopy.
This was the second attemp, the first one last is some kind of modern art because the plate slipped out of the frame.
For covering the motor as the biggest rotating part we had to chosse between IKEA ORDNING, a cutlery case and the Zeller „Mesh Style“ pen cup. The pen cup won, because its black, and we only work in black (it’s acutally dark grey, but who cares)
With the new RADAR optimized bumpers and the full enclosure it now looks kind of ugly less sexy than before. The cover is fixed on the payload mounting points and will be slided on top if everything is mounted and connected.
not so sexy vs. sexy climber
With all these new covers you an not touch any rotating parts on the climber. But we still don’t know how to touch rotating parts if your not allowed to stand next to the climber while driving.
To participate at SPEC in Japan the rulebook says: „You are not allowed to touch your climber when starting“ (freely translated), so our common technique to give it a little push over the blind commuting of the speed controller would not work.
We had several ideas of a spring loaded pushing thing, a second motor tor startup, a clutch… but we didn’t even try all settings of the Kontronik ESC which can be changed via an Android app (would rate it 0 stars) and be stored permanently until the next powerup. (If you work for Kontronik and can tell us why it does not store the PWM values set in the app, that would be great)
For faster testing, we used a RC remote this time- quite dangerous at an acceleration of ~40m/s² – but the ESC kept its PWM ranges most of the time. After 30+ failed start attemps on our tally chart we finally got the right settings. The climber pushes itself on a nearly vertical rope. For simulation of the canopy and IMU cube we added some weight with a professional mounting system. And it is still working.
List of other tiny problems to solve:
– ensure stopping before the top bumper is behind the climber
– finding a logo for the tshirts
Detecting the end of the rope / balloon at high speeds is difficult. A marking on the rope isn’t safe, endswitch not possible, laser rangig can be blocked by the rope. So why not try RADAR? This technology allows you to get high resolution distance readings and the doppler speed of (metallic) objects. We started looking for different ready-made sensors with a wide beam angle and medium to high range in june 2017 and found mostly automotive parts from Bosch, Continental and of course Autoliv. As Autoliv is around the corner of TUM, we contacted them and asked for their help. After a short impression of what we need they provided us two sensors with a cusom firmware which gives us a list of tracked objects over the CAN interface.
This week Autoliv finished the software and we were invited to their office. We presented our Space Elevators and they introduced us into the black magic of RADAR sensing.
Back at the WARR SE Lab (actually we work at home a lot in the past weeks because you can leave you stuff laying there, but „Lab“ sounds cooler than „livingroom“) we connectet the sensor to the microcontroller for testing and implementing.
We are going to participate SPEC2017, Mito, Japan, form 30.11.2017-04.12.2017 !
And because we want to share our journey and the last weeks before the competition we will write small articles about what we do.
We will try to write as entertaining as possible and include all experience we made. Not only the good ones.
So lean back, enjoy and grab a beer/coffee* and popcorn.
*we are not responsible for people dinking beer during their worktime