Big Friendly Robot Dog V1

Overview

At 2.5-ft tall and 26 lbs, the BFRD V1 is roughly the size of an average mid-sized house dog. Heavily inspired by Boston Dynamics’ Big Dog and Spot Mini line of quadrupedal robots, the Big Friendly Robot Dog V1 is an exploration of four-legged walking dynamics.

The four legs are articulated like a mammalian animal’s, with heavy-duty RC servo motors combined with automotive gas springs acting as semi-compliant elements to absorb shock and recycle energy from one step to the next.

Onboard Computer & Control

The BFRD V1’s onboard computer is an NVIDIA Jetson TX2 coupled with an Arduino Mega 2560, controlling locomotion, processes, sensors, and communications with the user. The control system is designed to keep the robot dog balanced and manage locomotion on a wide variety of terrain with real-time navigation.

Physics Simulator

A real-time quadrupedal physics-enabled simulation was built in Unity to accurately model the dynamics of walking, joint motion, and their effects on the robot dog’s position, rotation, and inertia. A simple machine learning model was trained to calculate the optimal walking gait and timing to maximize stability and forward motion, which can be played back in real time on the physical robot.

Walking Robots Are Hard

Balance and stability became difficult to control as soon as one leg lifted off the ground. The conclusion: while the current servo motors were strong enough, they were not fast enough to achieve an active walking motion without falling over.

At full load, the robot takes in 48–60 amps of continuous power at 5 volts. Achieving a truly active walk like Boston Dynamics or MIT’s Cheetah would require a leg redesign with faster, more powerful, and more precise motors.

Planned further development:

• Advanced simultaneous localization and mapping (SLAM) with LIDAR sensors
• Significantly improved motor setup for active dynamic walking