# Quasi-Direct Drive for Low-Cost Compliant Robotic Manipulation

## TL;DR

This paper introduces Quasi-Direct Drive actuation for low-cost, force-controlled robotic manipulation, presenting a prototype that balances affordability, dynamic performance, and usability for human environments.

## Contribution

The paper presents a novel Quasi-Direct Drive actuation paradigm and a low-cost, human-scale robotic arm with demonstrated force control and VR-based telepresence capabilities.

## Key findings

- Robot costs less than $5000
- Position-control bandwidth of 7.5Hz
- Repeatability within 4mm

## Abstract

Robots must cost less and be force-controlled to enable widespread, safe deployment in unconstrained human environments. We propose Quasi-Direct Drive actuation as a capable paradigm for robotic force-controlled manipulation in human environments at low-cost. Our prototype - Blue - is a human scale 7 Degree of Freedom arm with 2kg payload. Blue can cost less than $5000. We show that Blue has dynamic properties that meet or exceed the needs of human operators: the robot has a nominal position-control bandwidth of 7.5Hz and repeatability within 4mm. We demonstrate a Virtual Reality based interface that can be used as a method for telepresence and collecting robot training demonstrations. Manufacturability, scaling, and potential use-cases for the Blue system are also addressed. Videos and additional information can be found online at berkeleyopenarms.github.io