Welcome to the official 4253 Raid Zero build thread. Located in Taipei, Taiwan. We are the first FRC team in East Asia, and this is our 9th season of competition. This is our first official build thread.
We realised that it is probably unusual for a build thread this late into the season. However, due to the recent outbreak of the Wuhan Coronavirus in Taiwan, the government has suspended all school and school-related activities until the 25th of February. As such, we decided we would like to publicise our ideas and design processes to those who find themselves in our current situation.
We are deeply saddened by the impact of the Coronavirus around the world, and we send our heartfelt condolences to those affected by the pandemic.
If time permits, I will write a Mandarin version of this build thread for our Taiwanese and Chinese friends.
I plan on sharing the CAD of the robot after the conclusion of the 2020 official season.
Our lab hours are as follows (Tentatively):
Monday-Friday: 3:30~7:00 PM
Saturday: 9:00 AM~7:00 PM
In addition to the allotted hours, members of the team also work on the robot during their robotics or engineering classes.
We will be attending three regionals this year: Science Park Taichung (Taichung, Taiwan), Southern Cross Regional (Sydney, NSW, Australia) and Hawaii Regional (Honolulu, Hawaii, US)
With the regionals being back to back, we have decided to pack our robot in Pelican cases through checked-in luggage. We do not have enough time to ship our robot since we are an international team.
During kickoff night, our team gathered in our 3-story robotics facility dedicated to STEM education at 11 PM local time.
After the conclusion of the twitch stream, we split into small groups to analyse the game manual, each group led by one of the heads of the team. Each group was responsible for their respective section of the manual (EG: robot rules, game rules, etc.).
We then regrouped in our lounge area, and each head summarised their respective section.
Following the game manual analysis, we dived back into our groups to discuss game strategies.
At 3 AM, we decided to head back home for the night and rest for the following day.
This concluded our kickoff night.
In the morning after kickoff, we decided to dedicate the start of week 1 to game strategies and overall season workflow.
Our overall goal was to develop a robust and consistent robot which could see hours of practice well in advance of our first regional. Thus, we have decided to stick with our regular 6-week build season, as seen in traditional bag&tag seasons.
Our design mindset is as follows: the ability to obtain all 4 Ranking Points (RPs) without the aid of others. This design philosophy allows us to potentially get all the RPs by winning the match, 3-stages RP and end game RP. In the worst-case scenario going against three god-tier teams, we would still like to obtain as many RP if the odds of winning were against us. Ultimately, we will design our robot based on our analysis instead of forming a game strategy based on our robot design.
Here were our crucial findings:
- The odds of completing the 3-stage RP were less favourable than endgame RP.
- To obtain the end game RP, it could be achieved by either three robots hanged or two robots plus a balanced switch.
We also prioritised the robot mechanisms into three categories: Need, Want, Wish. The “Need” category is what we absolutely must need to be competitive. “Want” category is what would greatly benefit us, but is not a priority. “Wish” is what would be a reach in designing, but we dream of having that on our robot. Below is the list we made
Wheel of Fortune (WOF) manipulator
- Switch-centring Climb
- Trench Run capabilities
- Buddy Climb
After planning the priority level of subsystems, we moved on to the topic of the drive train, the most crucial subsystem of all. Before we begin brainstorming, our drive train has to meet the following conditions:
- Fit inside our largest suitcase of 65cm x 80cm x 30cm (25.5" x 31" x 12")
- Weigh under 15kg (33lbs) to obey airline regulations
- Easily detachable to allow ease in packaging other subsystems into multiple suitcases
Our first conclusion was to have a West Coast style cantilevering drive train. This style of drive train has proven to be effective ever since our first adaption of it back in 2017. With 2020 being a highly interactive game, we expect to encounter rough defence and more repairs than previous games.
The drive train will be constructed with 2" by 1" (2mm walls) box tubes, powered by 4 Falcons. The gearbox we decided to use was WCP DS Flipped gearbox.
There were multiple debates in regards to the ratios and wheel sizes. Ideally, we want a low gear for accelerating and point turning paired with a high gear to quickly traverse across the field in seconds. We also dived into the decision of using 4", 6", or 8" wheel. However, the verdict was quickly settled upon 6" wheel. The reasons being 4" wheels were not ideal to cross over the generator bumps. This was found through a quick CAD sketch along with proof of concept testing with our off-season bases. 8" wheel was discarded as the base will not physically fit inside our suitcase.
The wheel configuration was then debated upon. From 4WD to 6WD drop centred, corner omnis, etc. Our first concern was whether omni wheels could take the impact from going over the bumps. After abusement tests of our off-season base, we concluded omni wheels were prone to destruction over time. A 6WD was not ideal without omnis, so the configuration was down to 4WD or 6WD drop centred. We ultimately went with 4WD for the weight savings of the base and size constraints of the suitcase.
We then tested multiple types of wheels: Nitrile tread, Pneumatics, Colsons, etc. A 4WD with nitrile drew too much current, and to maintain the consistency of the robot’s performance throughout the match, this was out of the box. We ended up choosing WCP Pneumatic wheels. Those did not draw as much current during point turns and offered an extra level of protection going over the bump.
Attached is the image of the drive train CAD.
The drive train was fabricated in-house with our waterjet and welding station.
(More information will be written tomorrow, it is currently 2 AM in Taiwan)