This Fall was a productive semester for RoboNav. The team made great progress on Swervi, the newest IGVC robot, since plans for it started in the Spring of 2020.  As the manufacturing and assembly are nearing completion, the team has also made great progress on the electrical components for the diagnostic system. With the new drive train (swerve drive instead of differential drive), the software and electrical teams have been busy working together on the new controls system.  The team is currently on track for IGVC 2022 with big plans in the works for the new University Rover Challenge (URC).

The primary goal for Fall 2021 was to complete the manufacturing and assembly of Swervi. Despite starting on the designs and prototypes in the previous year, the CAD for Swervi was finalized during the summer of 2021. The mechanical team was finally able to start the bulk of production this semester. The hardest part of the job was building the frame. While the general design principles stayed the same with a main cabin for the electronics and separate spots for batteries and a payload, Swervi required a much different frame than Jessiii. It also required a new case to be made by Protocase, who has sponsored RoboJackets in the past.  Due to previous prototype work, the team already had the swerve modules ready (which is made up of the wheels, steering motors, and brackets to hold it all together). The team was able to assemble all the major components (the frame, swerve modules, sensor tower, and electronics case) together in December.  

On the electrical side of Swervi, the team was able to start implementing many design changes that have been in the works for the past year. One of the biggest changes to come was a new battery. If you are familar with the IGVC team’s past, you may remember the massive yellow lead-acid batteries previous robots used.  Since the old batteries were starting to fail, the team finally decided to switch to a much smaller 24V lithium ion battery to save weight and space. The other significant change was the motor controls. Jessiii only had two motors for driving, but Swervi has eight (one to drive and another to steer each wheel independently). This required more robust motor controllers, so the team got some off-the-shelf controllers designed specifically for robotics applications (ODrive controllers). While there is still work to be done to finish the firmware and logic board coordinating Swervi’s behavior, the team’s been able to get everything to move. 

Besides the motor controls, the electrical team has also been involved in a number of smaller PCB projects that improve Swervi’s performance and facilitate future development. Over the past year, the team has been developing a system of boards which the team was able to solder and assemble this semester. Here’s the highlights of each board and what they do:

1. Fan Control: This board runs fans in the electrical compartment automatically based on the temperatures inside.
2. Error Lights: Using some NeoPixels (addressable LEDs), the logic board can display error codes to make debugging easier.
3. Current Sensing: This board can read the battery’s current for monitoring power consumption.
4. Remote Display: This board exists outside of Swervi and displays important diagnostic information for the team.
5. Power Hotswap: This board is an important addition to the power distribution of Swervi. Someone can switch power from the on-board battery to a wall outlet, which makes working on the computer and other components easier without depending on a fully charged battery.

The last PCB the team is currently working on is a redesigned logic board for the Mbed, which bridges the computer and motor controllers together. The electrical team was able to make great progress on each board and is ready to put it all together next semester.

While Swervi is not entirely complete for testing, the software team has had their fair share of things to work on this semester since the new control system poses many challenges. Primarily, the ROS nodes used for path planning needed to be redone to account for the ability to move laterally. With the changes to path planning, the team has also been working on using the GTSAM library for SLAM (simultaneos localization and mapping). The GTSAM library is a robotics library developed by GT professors and students that uses factor graphs for various robotics uses. On top of this, the vision system needed a refresh to account for the new cameras.  Since Swervi can move in any direction, it needs more camera coverage to see the lines and barrels around it. The team shifted to using three cameras with 130 degree wide angle lenses to cover the full 360 around the robot. The software team has been fine-tuning a pre-trained neural network model to support multiclass segmentation for these new cameras. The new members of the software team have been working on a new project: a new testing framework, including new unit tests, that the team can use to check different parts of the software stack without relying on the simulation.

Of course the work towards URC has not stopped. Following the 2021 IGVC, the team decided that they would work on both competitions as there would still be a lot of work to do before competing at URC. The mechanical team has been designing the mechanical arm necessary for the future rover during this semester too. They plan on having a design review for it this coming semester. The software team has also been laying the groundwork. A new GitHub repository has been made and the basic ROS framework has been set up. For URC, the team is using ROS 2, the newer version of ROS. One of the biggest challenges for URC currently is the science challenge. During the competition, the rover will need to take a soil sample and perform various tests on it. To do that, the team will need to create mechanisms to perform the tests, which is something a RoboJackets team has not done before.  The team is currently looking for new members that have experience in this area to form a new subteam, the science team.

RoboNav members have a lot to look forward in the coming year and semester.  Completing Swervi, the tenth IGVC robot, is the ultimate goal. With the 2022 IGVC quickly approaching, the team will begin testing the diagnostics system and wiring up the completed Swervi chassis. In addition to the motor controllers changing, the e-stop circuitry needs to change to compensate for the additional motors. The software team also hopes to revamp their simulation for Swervi until it’s ready to drive. The new drive train posed some challenges during this semester, but the new testing framework should help resolve those issues.  And once Swervi is ready to go, the team can turn its attention to preparing a design and presentation for the URC acceptance process.

RoboCup 2022 is 7 months away, and the team is hard at work tuning gameplay and building their second fleet. 

Having achieved a stable platform for the software team to test on, the electrical and mechatronics subteams are making good progress on the second fleet, with the intent of using the new bots to test improvements on the electrical and mechanical side. On the topic of the electrical improvements, Project Manager Bernardo Perez said: “We decided to do revisions to some of our most important boards, which largely entailed replacing obsolete/out of stock components and fixing some lingering issues with our previous design.” The subteam is ordering a new set of boards with the aforementioned revisions, which they plan to assemble in the spring. Aside from the board revisions, a robot shell ID board is also being added, which will allow the bots to “automatically determine their IDs at the start of a match based on the color code of their shell”, instead of team members having to manually set the IDs before every match and testing session.

The mechatronics team spent the fall designing a number of small mechanical improvements that they plan to test on the new fleet, which they will begin assembling in the spring. “Everything is electrically compatible… so we’ll be testing these alongside our old robots to compare and make changes as needed,” said Dan Lam, the RoboCup mechatronics lead. Regarding specific changes, the team plans to increase the width of the dribbler, and change its pivot geometry and damping materials to improve the bots’ ability to receive passes. The solenoid’s attachment has been simplified to allow for easier removal, now only attaching to the baseplate as opposed to multiple other parts like it was before. 

For the chassis and drivetrain, the midplate and baseplate attachment “is now independent of motor stands, allowing for easier disassembly and access to solenoids for troubleshooting / replacement,” Dan said. The subteam is also adding dedicated wiring channels to reduce the likelihood of “wires getting caught on the shell and and being plugged into the wrong places.” Finally, the shell design was overhauled – instead of having a top half that constantly got caught on wires and a bottom half that was fixed to the baseplate and restricted access to solenoids and motors, the new design is a single piece that attaches to the midplate. This not only alleviates the previously mentioned issues, but will also make it easier to swap out color plates.

The software team continues to make progress on their overhaul of the team’s gameplay, implementing a number of new features since the 2021 competition. The most important of these features is the fleet’s ability to pass the ball to each other. In the past, the team was unable to implement passing due to their role assignment algorithm, which constrained bots to three levels of priority and was not dynamic enough to reassign roles at the speed required to determine effective plays. Having now overhauled this process, the team was able to implement passing, which opens up a number of gameplay strategies that weren’t available to the team in previous years. Said Bernardo: “This feature is still in its early stages, but has been tested and shown to be functional through simulation.”

Congratulations to the entire team for all of the progress they’ve made, and we’re excited to see what they accomplish in the upcoming semester!

The team has been preparing to enter evGrand Prix Autonomous, the go-kart scale autonomous racing competition, starting all the way back in 2019 after the conclusion of Sparkfun AVC. This two year time frame gave the team a unique opportunity to thoroughly flesh out vehicle designs. However, as most in RoboJackets know, the real test of designs are at competitions. This past September at the Purdue University Track, the team was able to finally do just that at evGrand Prix 2021! You can read more about the competition and the results here.

The team was incredibly proud of the second place result (especially considering this was the first ever team entry into the competition), but running the robot all week made clear some places for improvement on all subteams, which inspired many of the projects the teams have been working on post-competition. 

Mechanical had multiple projects inspired by pain-points at competition, with one being a new component mounting system. An initial goal of the robot was to be able to handle light rain (partially from competition rules and partially from convenience of not needing to rush for cover if rain starts). However, competition crunch came around and the electrical subteam had more parts to mount. This led to components to be mounted in three different containers across the robot and a few outside of the containers. After further reassessment from competition, the team decided to consolidate all of the components into one large container. They are actively capturing the parts that needed to be added in the CAD and designing new mounts where needed.

Another issue at competition was that the brakes were not very easily controlled and the motors had a risk of burning out. This led the team to pursue a lead-screw motor design to actuate the brakes, to both more finely control the braking for use in speed control along with reducing the likelihood of motor burnout. They are working on force calculations and CAD design to prepare for manufacturing in coming months. Additionally, the mechanical team has been working on other projects like a revised steering system, new mounting for cameras, and battery covers. 

Electrical, also inspired by the problems faced at competition, have many active projects. Almost all of the new projects now utilize a STM32H7 based microcontroller board, with the team opting to use existing Nucleo boards with daughterboards instead of complete custom boards due to the chip shortage. 

One of these projects involves developing a new Ethernet vehicle protocol.The entirety of the car’s electronics (barring some cameras and IMUs) communicates over Ethernet. This includes all of the existing custom boards, the Intel NUC, GPS, and LIDAR. Occasionally the custom boards would lock up and no longer communicate, often bringing other boards down with them. The team suspected the combination of TCP and use of under-specced WizNet chips combined with the simpler Atmega microcontrollers. This led to the team transitioning to using UDP and STM32 with built-in Ethernet support and multithreading. Current smaller scale testing indicates great performance improvement, but larger scale testing and full system integration are still required. 

Electrical and mechanical are collaborating on improving aspects of the steering system. Originally a stepper motor with a custom board, it was decided that a brushless motor with feedback control would better handle the power requirements along with being much faster. The team decided to utilize an ODrive board. This, coupled with absolute encoder and new steering models controlled by a new STM32 board, will allow for more accurate and faster motor control. Electrical is also working on an enhanced remote control system and battery monitoring system. Design of the daughterboards for all of these boards along with firmware will continue into the spring.  

The software team has taken on a new daunting task: transition to ROS 2. For many years, the software has been written for ROS 1. Due to major architectural changes, ROS 2 requires a redesign or conversion of many aspects of the software stack. As RoboJackets software training has now shifted to ROS 2, now was a good time to transition as ever! The difficult part of the ROS 2 migration was laying out all of the dependencies of the ROS 1 codebase and determining which already had ROS 2 and which would have to be written by the team or substituted. The major issue that the team has been working on is updating the sensor drivers to communicate with ROS 2 since many have not been updated for years, with the RTK GPS and IMU being the main focuses. 

The path planner (which determines how the robot should drive) utilized standard ROS libraries, so updates for ROS 2 had been made. However, competition indicated that some aspects were not as customizable or true to real-world contestants as the team would hope. Now served as a good time as any to re-architect the planner, largely in part due to the bloated feature support for by-gone platforms such as Macaroni and Bigoli (discontinued in ~2018 and ~2019, respectively). The team looked into using teb_local_planner because of the support and built-in functionality, but the need for a specific target destination didn’t work well for not knowing the track or multiple laps. The team settled on writing a brand new planner with heavy inspiration from the old planner, which progress will be carried on into the spring. The new members have also just finished training and are hopping on new member projects going into the spring as well!

The next evGrand Prix competition is going to be April 2022, so the team will certainly be busy going into the Spring!  

RoboWrestling has been busy the last semester designing their newest generation of 3 kg Sumo Bot, dubbed Spici. The biggest change with this new robot is that the plow is hinged. RoboJackets has iterated on a few plow designs throughout their history, beginning with a compound plow with a rigid aluminum section at a steeper angle and a flexible spring steel tip at a low angle. More recent plows have reduced the difference between these two angles, and replaced the flexible spring steel with a rigid steel tip. What Spici adds to that is a hinge on the plow that prevents enemy robots from using our own plow against us. 

In the event that an enemy robot’s plow is able to get under our plow, instead of the plow being used as a longer moment arm, the new hinged plow design will simply rotate out of the way, preventing Spici from being flipped as easily from the front. To ensure the plow remains flush with the steel dohyo floor otherwise, weaker magnets are attached and maintain a downward force.

The team plans to begin manufacturing Spici in the spring semester. Aside from Spici, the team has also made small adjustments to Guccii and Kirbii, including addressing mechanical issues with the plows and making changes to the sensor arrays on the robots. Like Spici, both Guccii and Kirbii will use 6 TF Minis (miniature single-beam LIDARs) in an array to detect and track their opponents.

Unfortunately, because of COVID considerations, including the travel restrictions in Japan, the All-Japan Robot Sumo Tournament (our typical competition for Sumo) has been put on indefinite hiatus. RoboJackets is continuing development on our robots and will be keeping our eyes out for other competitions where we can bring our robots. Additionally, because we have multiple functional robots, the team is able to test them against each other to practice for when competitions present themselves again. The team has plans to build a full size dohyo for this exact purpose, which will enable accelerated iteration even in the absence of competitions.

If you’ve been reading the newsletter, you’d know that the 3lbers in BattleBots have been hard at work this past semester working on their 3lb robots and getting them ready for Motorama 2022 in February. These are not the only robots that BattleBots makes and have been working on. We’d like to take this time to give an update on all the other larger robots that the experienced members of BattleBots have been working on this semester.

First is Anarchi. Anarchi is a 30 lb modular combat robot that can be switched between two combat configurations, pictured above. Modular robots present the advantage of being able to change their weapon based on their opponent, and can also enable replacement of the entire weapon system if one is rendered inoperable in combat. The team has spent a great deal of time designing the robot and ensuring the strength of the connection points, and have moved on to manufacturing. The team has made good progress on manufacturing chassis pieces this semester, shown below, and plans to dedicate the majority of the spring semester for weapon system manufacturing. The team is planning to reuse the weapon from Valkyri, an earlier horizontal spinner, to ease manufacturing.

Next up is Bucki. Bucki is a 12 lb pneumatically actuated flipper. Bucki is expecting to make its debut at Motorama 2022. Pneumatics (and flipbots) are both relatively new for BattleBots, so it will be a learning experience to run this robot. Over this semester, they’ve been able to complete the chassis, pictured below. The team plans to hit the ground running next year to get the weapon system and electronics working in time for competition. The team has seen some delays in shipping for parts, which has put them slightly behind.

The next robot is Binari. Binari is a 30 lb horizontal spinner with two independently powered weapons that uses shuffler modules used for locomotion instead of the more typical wheels. Binari’s shuffler modules were designed taking into account our experience with shuffler modules for Apachi. The team has suffered from part delays, but recently received the shuffler module parts, which will enable faster progress on those essential components. The team has begun manufacturing chassis pieces, including the side plates emblazoned with binary.

The penultimate robot is Chonkii. Chonkii is a second iteration of Chonki and is a 30 lb shell spinner with shuffler modules. The chassis and electronics are finalized and the shuffler system appears to be working well. The team is expecting to spend most of the time next semester on putting together the weapon shell. Chonkii will be competing at Motorama 2022.

The last robot is Hocki. Hocki is a 12 lb “melty brain,” a robot that is constantly spinning and moves across the arena by adjusting the relative motion of the two wheels. Hocki will be competing at Motorama 2022. The robot is now fully assembled, but the team has been working on debugging software and hardware to enable it to compete. The team has also been working on a custom “black box sensor” board. The black box sensor uses a gyroscope, accelerometer, and measurements of weapon motor curent to better understand what happens when a robot weapon makes contact with an opponent, which will enable better modeling in the design process.

The robots that aren’t going to Motorama (Anarchi and Binari) were planned to compete at a competition later in the year, but due to rules changes will not be able to compete. BattleBots is still looking for a competition for them to compete in, but the team is overall excited about the new and experimental robots they’ve been working on. We look forward to reporting on how the robots fare in competition at Motorama 2022 and beyond.