This robot differs from other spring-mass-based bipeds in the type of actuators used -- specifically, quasi-direct-drive rather than series-elastic. This allows the "springs" to be implemented in software rather than hardware, simplifying the design and reducing cost.
This is the actuator I designed for use in this project: OpenTorque Actuator
Blackbird stands 1.2 meters tall and weighs roughly 15 kg. Its estimated operation time is 4 hours with a 400 Wh battery. The total BoM cost is less than $3000.
Once the prototype Blackbird is built and walking (estimated February 2019), I'll open-source the design so anyone can build or modify it. I believe that hobbyists and researchers can hugely benefit from access to a low-cost, highly capable biped platform like the Blackbird.
Some reference materials I'm using:
- Walking and Running with Passive Compliance: Lessons from Engineering a Live Demonstration of the ATRIAS Biped
- Performance Analysis and Feedback Control of ATRIAS, A 3D Bipedal Robot
- Control of Forward Velocity for a Simplified Planar Hopping Robot
- Embedding of SLIP Dynamics on Underactuated Bipedal Robots through Multi-Objective Quadratic Program based Control
- A low cost modular actuator for dynamic robots
- Design for 3d agility and virtual compliance using proprioceptive force control in dynamic legged robots
- MIT Underactuated Robotics Lectures
- RI Seminar: Jonathan Hurst : Designing Robots to Walk and Run
- Studywolf blog