Titania design begins

[Michael Wimble]

The follow-on to Sigyn is Titania. It’s largely a complete redesign incorporating a lot of features/ideas from Sigyn.

Sigyn’s original, achieved goals included:

• Recognize the charging station
• Autonomously move to pose in front of the refrigerator that would allow opening of the door and viewing/recognizing objects in the refrigerator
• Move to the charging station, start charging, disengage from charging, all autonomously.
• Demonstrate dynamic obstacle avoidance while moving.
• Demonstrate reliable localization while traveling throughout the house.
• Create tools to map WiFi strength throughout the house.
• Create good WiFi field strength throughout the house, generally providing a few hundred megabits/second everywhere.
• Create behavior trees, with reactive safety handling for:
• Fetch me a beer demo.
• Go to charging when battery charge approaches a critical level.
• Patrol the house.
• Complete rewrite of the safety system.
• Create a human-in-the-loop communication system as part of the safety system, where when presented with a safety issue, a message is sent to a human with a choice of responses the human can indicate the robot should take. The human-in-loop system must work when the human is far away from the robot (thousands of miles).
• Demonstrate reliable movement between rooms with narrow passageways.

Extra credit goals not achieved (because the gripper needs a redesign):

• Open/close the refrigerator door.
• Recognize objects in the refrigerator.
• Remove/place objects in the refrigerator.

I’m working on Titania’s various specs for the overall goals, goals for redesign of all of the subsystems, and so on. I’m generally using design-by-spec even more than before. Titania will have:

• A new arm system and gripper
• New sensors—more kinds, more of the older ones, upgrades to better sensor hardware
• Brushless motors that are more powerful and pretty quiet
• Bigger wheels with more clearance
• Better mechanicals modeled better so I can do more design verification. 

Titania will build on the existing “patrol the house” behavior tree that already allowed Sigyn to roam the house; the new behavior tree will include more “look for something being wrong and react to it” behaviors. I’m doing a fairly big research into safety, looking at standards and practice examples demonstrated by other robots, and I’ll continue to improve on how safety is achieved. Part of that is a new power-on electronic design that includes:

• Precharge circuit. This prevents frying the main, power-on circuitry by precharging the voltages on both sides of the contactor relay.
• Bigger power allowance. The main circuits should now handle about 100 Amps at 36 volts.
• Big, honking “system power” disconnect switch. Different from power-on and e-stop switches.
• Always-on circuitry. This monitors battery charge and performs the power on/off sequence, like managing the precharge circuit.
• Power On and E-Stop are physically big but electrically small switches that signal the always-on circuitry to do the right thing. E-stop also physically disconnects the contactor relay. Power-on can also signal the various systems to shut down in a controlled way.
• Switch to turn off the always-on circuitry so it won’t drain the battery when the robot is in long-term storage.
• Power reset and software reset switches for all of the 3 or 4 Teensy subsystems. Needed because the software used for uploading new firmware requires a human button press.
• E-Ink (probably) status display that the always-on circuitry can show the state of various things.
• I may move to an independent micro-SD card system to record the somewhat voluminous data logs from all of the Teensy subsystems. Currently, each Teensy has its own SD logger.
• Moving the whole control panel to a more accessible area.

There is lots more. Sigyn went from a box-shaped in the Raven ancestor that had a hard time moving reliably around the house to a robot that frequently patrolled the house and, occasionally, fetched me that beer (or soda, in my case). As I work towards that personal assistant to help me as I age, each iteration adds features and design improvements.

Here is a short video showing the simulation of the design of the carcass with just enough detail to ensure the new ODrive motors and motor controllers and the new battery and power converters will all fit on the new chassis. The 3D model has been sent to JLCCNC for fabrication as they can laser-cut, bend, drill, and tap the chassis for less cost than I can buy the plain aluminum disk itself (if you don’t count shipping costs). And their metal finishing is much better than I can achieve.

[Karim Virani]

The next all new chassis that I design will prioritize an automated battery swap (with no interruption) for a much higher duty cycle.  I know that's a tough challenge. Is that a goal for Uriel/Uma/Una/Ursula/Umbra? Not sure of your naming scheme's rules...

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[Thomas Messerschmidt]

You’ve been working hard!

Thomas Messerschmidt

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Need something prototyped, built or coded? I’ve been building prototypes for companies for 15 years. I am now incorporating generative AI into products.

Contact me directly or through LinkedIn:   

https://www.linkedin.com/in/ai-robotics/

On Aug 24, 2026, at 1:00 PM, Karim Virani <ponder...@gmail.com> wrote:



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[Michael Wimble]

Not currently. I don’t have a scenario where my robot needs to work continuously beyond 6 hours at a time, which is my current estimated time budget based on the new battery power and historic power draw. My battery is also pretty big and weighs 30 pounds. The weight is part of the design to keep the robot from tipping over and it will be enclosed in metal with specialized venting to deal with a battery fire. I’ll be interested to see how you achieve your design. 

On Aug 24, 2026, at 1:00 PM, Karim Virani <ponder...@gmail.com> wrote:



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[Chris Albertson]

Do you really need a battery swap? You could charge the robot the way people charge electric cars. No one waits for the battery to get low and then charges it all the way up. No. They usually simply plug it in when they are not driving. With a home robot, I assume most of the time it has nothing to do, so why not go find a charger? Maybe the robot could do what people do, opportunistic charging.

They make standard wall outlets that also have USB ports for charging. I wonder if a robot could be designed to find a USB-C port and plug the cable in? In time, people will have dozens of these all over their house.

If you use USB-C then the robot can even find times when it can work and charge at the same time. Say it is cooking dinner and sees a USB-C outlet on the kitchen counter and figures it can top off while working.

I can imagine an evil robot unplugging your phone so it can use the charger.

[Karim Virani]

My application is an outdoor property roaming sentry bot, so I'd like a high uptime. I also don't want battery mass to go above 25% of total system weight. It has to be agile over non-paved terrain. The bot should be able to do rounds at unpredictable intervals, but likely 80-90% duty cycle. The continuous compute requirement keeps going up as we put more AI workload locally on the bot. My preferred method is to keep AI in the cloud, but when networking goes down (and it always does) local models help keep things running.

Thanks Michael, I now understand the rationale of your battery strategy. Is the big blue cubeoid in your fusion model just the battery?

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[Michael Wimble]

Yes. Here is the battery I decided to get. I tried to get a custom battery but the response was too slow and wanted too many exchanges before we got to the nub of it.

Dyness 36V 55Ah LiFePO4 Lithium... https://www.amazon.com/dp/B0FSL689V3

> On Aug 24, 2026, at 4:31 PM, Karim Virani <ponder...@gmail.com> wrote:
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