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A project log for DeltaWalker

Quadruped robot with legs in delta configuration.

Martin Vincent BloedornMartin Vincent Bloedorn 02/25/2018 at 20:100 Comments

Before I go into detail on the design, assembly and firmware of the DeltaWalker, allow me to briefly outline the current state of the project.

Although I've started it some months ago, I probably worked on it for less than two weeks on total. I started out by taking a close look at Simon Kalouche's work (mentioned in the project description), and then getting a lot of those 9g servos from China. 

Once o had the components, I prototyped the first leg (no photos of it, unfortunately).  As you probably see in the pictures, I used 3d-printed flex parts as joints. They work suprisingly well on that scale, and I'll get into more detail on that in further posts. After a successful leg prototype, I went on to design the body and the home-milled PCB (also, more on those later). 

The PCB essentially connects a Teensy 3.1 to a 16-channel servo multiplexer, breaks out some connections for a planned ESP8266 (and/or a bluetooth module), and allows everything to be neatly powered by a 2S LiPo battery being fed through a LM2596 buck-converter.

Once the hardware was in place, I scraped the internet for a good implementation for delta inverse kinematics. Again, more detail on that later, but if you're in a hurry, this is gold. With those in place, I started working on a simple firmware and prototyping the gait algorithm (still wonky, as you'll see). 

Last, but not least,  I used a IR diode/receiver pair to build a simple joystick for the robot. I'll dump IR in favor of bluetooth anytime soon, but in the meantime, it's what I had lying around.

So, finallly, there goes a quick demo video of me playing around with some body translations and showing the (still fairly drunk) gait: 

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