As everyone is waiting for the answer of how we did in the competition. We’ll get to point: WE WON!! At least one of the three first matches ;-). Which meant we couldn’t compete in the next round.
This isn’t because the competition was too good, it’s just that Fanny wasn’t what it could and should be. We have all the hardware to make a “killer” robot but we didn’t had the time to get everything working as it should. Before this competition we have participated in the same competition already two times and ended in the top 3 each time. We started this when we were students and had a lot of time. But everyone graduated and got a job and we just underestimated how much time we had left after work.
We lost lots of time by trying and learning new things: 1. We tried to 3D print our own gearboxes (will be continued for sure) 2. Programming a new processor we had no prior experience with 3. Working with a new kind of motor drive 4. Adding our own sensors to the motors for closed loop control (which costed the most of our time) 5. Working with new sensors
Instead of adding features and improving the robot we were stuck in a loop of fixing things and troubleshooting. We did learn a lot from this project. And you can definitely expect a comeback from us!
And a big thank you to all our sponsors and partners who supported us through this!! See you in two years!!
If you’d like to pay a visit at the robot competition you could find more information here: https://www.makerfairegent.be/robotcompetitie?rq=robot The robot competition takes place at the first ever Belgian makerfaire.
The base of our robot isn’t the most impressive part from our robot but without the base plate we would just have a bunch of lose parts. With our Shapeoko XL from Carbide 3D we were able to machine our base plate from a 3mm aluminum sheet.
The previous wheels had the problem that the wheel hub was able to slip inside the silicone cast. If this would happen while the robot is pushing this means we won’t be able to utilize the full pushing force of the robot. With this in mind we designed new wheels in FreeCAD. Fortunately we had some silicone left over that we got from VOSSCHEMIE.
During our first test run we discovered that the hot glue was not sufficient to keep the hall sensors in place. When the motors get hot (this happens when they stall) the hot glue easily melts and the sensors get loose.
We dismantled the whole robot and the motors. After separating the rotor and stater it was easy to glue the hall sensors back in, but this time using epoxy. The epoxy glue should have a higher melting temperature.
After soldering wires to the hall sensors the motors are put back together. Using our scope we could see they are working normally again! Hopefully they won’t come loose this time! ^.^
Today we tested for the first time the BLDC motors driven by the ODrive together with our VL53L0X ToF sensors. This simple demo program shows how the motors spin faster when something approaches the sensors.
Now that we have a small working setup we can build it all into an enclosure and start working on a program for the STM32F7. Hopefully we will soon have something that can drive around the house 🙂
As we mentioned before one of the most important parts of the robot are the wheels. The wheels are needed to transfer the motor power into pushing power. Without good wheels the wheels will slip and the motor power will be useless.For this reason we will make our own custom wheels with silicone rubber from VOSSCHEMIE.
It all starts by designing the wheel in 3D, for this we use FreeCAD.
To cast the wheel we need to have a mold for this we also use FreeCAD.
Next step is to 3D print everything.
Now we can finally start casting the wheels. For this we use 2 part silicone: SICOVOSS from our sponsor VOSSCHEMIE. Part A and B need to be mixed in a 1:1 ratio by weight. First we calculated the needed volume to fill the mold and calculated the desired mass we needed to fill the mold.
And then the mess could begin!
And here is the result after waiting a long time, the de-molding time would be between 6-7 hours but for this cast the time needed before be-molding took much longer. Probably because of the pigment used.
Final result !!
Thanks again VOSSCHEMIE for being our sponsor for the second time in a row!!!
For previous robots we relied on Arduino for the controlling unit. But this time we wanted to go to the next level and use a really advanced and capable microcontroller. Fast robots require fast brains, so we need a fast microcontroller. Last year I was a volunteer at The Things Conference from The Things Network. At the conference I was lucky enough to meet Benjamin Guilloud one of the Technical Marketing Engineers from STMicroelectronics.
STMicroelectronics is the only European microcontroller manufacturer and they have a big range of products, from microcontrollers to sensors.
I contacted Benjamin and asked if ST would like to support us by giving a development board and maybe a few of their Time Of Flight sensors. And yes they did, they send us a few development boards, a few Time Of Flight sensors and even some of their high-end microcontrollers. This sponsorship will not only give our robot the brains we need but also the eyes to find our opponents.
Thank you very much Benjamin and STMicroelectronics, your support is truly appreciated.
You may have a fast, smart and powerful robot. But none of this makes sense if your robot doesn’t have good grip on the arena. For this purpose many sumo robot builders cast custom rubber wheels or buy special wheels from the internet.
We wanted to make our own custom wheels and for this we teamed up with Vosschemie Benelux.
Vosschemie was already a sponsor for our previous robot, the wheels of the previous robot didn’t had any slip and they were even able to stall the motor. Because they offered so much grip we adhere to the silicone of Vosschemie Benelux.
The wheel making process for the wheels from the previous robot.
Today I went to Vosschemie Benelux in Lier to pick up the new sponsorship. We even got some green pigment to color the wheels.
Thank you very much Vosschemie Benelux for willing to be our sponsor again!!