SB 2021 Patreon Report

We hadn't had much activity on social media lately, and we're terribly sorry for this.

However it doesn't mean we sat back and did nothing all that time, though some things went pretty tough. No matter what, we continue our work on the Sweetie Bot Project!

And the first thing we should mention - we’re done with consumer grade servos. Of course, nowadays Proto2 and Proto3 include them - Dongbu Herkulex, to be precise.

What seemed to be a nice decision back in 2017, now presents a whole lot of  problems. They have large response time, insufficient control capabilities, high price and they are hard to find. The same also applies for third-party components of Proto2 – brackets, specifically. Originally taken from Hovis robot kit, they had been out of stock for a long time, and only recently reappeared on the market for higher price. We just can't rely on such a supply if we plan to manufacture the robot in the long term.

Since servo characteristics are critical to robot dynamics, we came to the decision of making our own servo motors. And currently we are working on two servo models simultaneously - KonServo and KonServochka.

1. KonServochka

Also known as “the easy way”. We took a cheap simple drive without feedback capabilities, but with good mechanical specs, and replaced its electronics with our custom controller board. That will allow us to implement all the necessary features the way we want it to be (current feedback, point-to-multipoint network and so on, which are only present in high-end servos).There are similar projects like OpenServo and OpenServoCAN, but they are abandoned. Thus the servo we’ve chosen for modification can be significantly improved without its price (and hence the robot’s price) rocketing. Currently we’re working on its control firmware.

2. KonServo

But "the easy way" doesn't provide much flexibility, since we're bound to its motor and mechanical specs, so it's time to delve deeper. In order to achieve the full potential of motion abilities, we need to build almost all the hardware from scratch. This one will be bigger, stronger, BLDC based servo with custom reduction gear. It can be used for better and bigger robots. Here’s the first 3d printed prototype:

The early version of the reduction gear is on the following picture.

The type of gear we've chosen provides the best fit to small dimensions that we need, however, it is very demanding of the gearing parts manufacturing accuracy. Their implementation is possible with the use of durable plastics, such as PA-6, POM or PEEK, and CNC machining, which we've decided to try.

More details on both servo models will appear later next year. So, stay tuned!

3. That's not all, folks! Meet Sweetie Bot Proto v2.5.

The next image is one of her test render. As you can see, we're also experimenting with optional panels to cover all the internals for a more appealing look and basic protection:

This robot will be made using our KonServochka servos we mentioned earlier. As for the bracket material, we decided to go with aluminium, due to its lightweightness and durability.

4. Tail & Ears movement

5. Mane for Proto3

And finally, Sweetie's hair is going through another iteration of its development. Currently our new couturier completed the mane, and now the tail is on its way.

Happy new year everypny! Thanks for the support.