I’ve previously built several robot dogs which used a variety of servos and brushless motors. The most agile robot dogs are the ones with back-drivable low-ratio reducers which allows the motor to be back-driven so we get some natural spring in the legs – which can be controlled on the fly with software. So it’s time for openDog V3 – this version uses my Cycloidal Drives which I’ve developed over the last few months. I will eventually publish the CAD and code as open source when it works.